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Effect of replacing soybean meal by extruded chickpeas in the diets of growing–finishing pigs on meat quality
MEAT SCIENCE Meat Science 73 (2006) 529–535 www.elsevier.com/locate/meatsci
Effect of replacing soybean meal by extruded chickpeas in the diets of growing–finishing pigs on meat quality Vladimiros Christodoulou a, John Ambrosiadis b,*, Evangelia Sossidou a, Vasileios Bampidis a, John Arkoudilos c, Borris Hucko d, Constantin Iliadis b
e
a National Agricultural Research Foundation (N.AG.RE.F.), Animal Research Institute, 58100 Giannitsa, Greece Aristotle University of Thessaloniki, Faculty of Veterinary Medicine, Laboratory of Technology of Animal Origin Food, 54124 Thessaloniki, Greece c N.AG.RE.F., Institute of Technology of Agricultural Products, 14123 Athens, Greece d University of Agriculture, Agronomic Faculty, Department of Animal Nutrition, 16521 Prague 6-Suchdol, Czech Republic e N.AG.RE.F., Fodder Crops and Pasture Institute, 41335 Larissa, Greece
Received 1 August 2005; received in revised form 8 February 2006; accepted 8 February 2006
Abstract The main objective of this study was to evaluate the effect of the replacement of soybean meal by extruded chickpeas in diets of growing–finishing pigs on meat quality. In a 17 wk study 48 growing–finishing crossbred pigs were fed ad libitum. The experimental design included four treatments, each one of 12 pigs; the ECKP0 treatment was fed with diet containing soybean meal and no chickpeas (control), while treatments ECKP100, ECKP200 and ECKP300 were fed with diets containing 100, 200 and 300 kg/t of extruded chickpeas, respectively. The lean meat quality of the longissimus lumborum et thoracis muscle was evaluated by chemical analysis (moisture, protein, fat and ash), fatty acid profile, pH measurement, cooking loss, color evaluation, and sensory evaluation. Odor and taste, tenderness, juiciness, and overall acceptability were scored on 1–10 scales by a group of 10 experienced assessors after a standard cooking regime. Small differences were observed between control and experimental groups in chemical composition (P > 0.05). Fatty acid profiles, pH measurements and color evaluation did not differ among treatments (P > 0.05), while cooking loss was significantly lower in the control group (P < 0.05). The taste panel gave slightly higher scores for the tenderness and juiciness for the control group compared with the chickpea treatments (P < 0.05). No differences were observed between control and experimental groups in taste scores (P > 0.05). It is concluded that the replacement of soybean meal by extruded chickpeas, when substituted isonitrogenously and isoenergetically at inclusion levels up to 300 kg/t of pig, does not influence significantly meat quality. 2006 Elsevier Ltd. All rights reserved. Keywords: Chickpeas; Extrusion; Pigs; Meat quality
1. Introduction Recently, research on the replacement of soybean meal (SBM) with other protein and energy sources in farm animals’ diets became of major financial importance in most European countries. The reason is that the majority of raw soy supplies in Europe are imported from non-European countries. The chickpea (Cicer arietinum L.) is one of the world’s most important grain legumes (FAO, 1993). In *
Corresponding author. Tel.: +30 2310 999814; fax: +30 2310 999812. E-mail address: [email protected] (J. Ambrosiadis).
0309-1740/$ - see front matter 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.meatsci.2006.02.008
Mediterranean countries, it is cultivated principally as a legume crop, since it is well adapted to semi-arid conditions, with some irrigated varieties yielding as much as 3.5 t/ha of seed in autumn seedings (Iliadis, 2001). Although most chickpeas are produced for human consumption, they provide the livestock industry with an alternative protein and energy feedstuff. Shimada and Brambila (1967), in a series of three experiments, studied the chickpea as a source of both protein and energy for the growing pig indicating that the raw chickpea supplied adequate protein, energy, and amino acids to support satisfactory growth and efficiency of feed utilization, even when chickpea meal supplied the
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major portion of the diet. Zamora, Aguirre, Shimada, and Martinez (1975) Cazarin, Bravo, de Uriarte, and Shimada (1976) have shown that chickpeas can completely replace SBM in practical sorghum–SBM diets for growing–finishing pigs without affecting pig performance or carcass quality. Friedman (1996) described chickpea protein quality as being equivalent to that of SBM and chickpeas have been reported to be suitable as a protein concentrate for pigs (Batterham, Saini, Andersen, & Baigent, 1993; Mustafa, Thacker, McKinnon, Christensen, & Racz, 2000). More recently, Christodoulou et al. (accepted) showed that partial and total replacement of SBM with extruded chickpeas, at inclusion levels up to 300 kg/t of concentrate mixture, as the main protein source in growing pig diets resulted in similar productive traits for the full growing/finishing period. Although the effect of chickpea inclusion in pig diets on growth performance is well established, there is little information about the meat quality produced by its use. The aim of the present study was to investigate the effect of the replacement of SBM by chickpeas in diets of growing–finishing pigs on the pork quality. 2. Materials and methods
(Cheeke, 1999). In preparation for extrusion, chickpeas were ground to pass a 2 mm screen using a hammer mill. Ground chickpeas were extruded at 120 C (i.e., barrel temperature near exit) for 20 s using a Berga model ME-103 extruder (Berga, Impianti Cereali S.p.A., Treviso, Italy). The extruded chickpeas were reground to pass a 2 mm screen before mixing into the diets. The combination of process temperature and heating time used was based on reports of Van der Poel (1989) and Vooijs et al. (1993). 2.2. Evaluation of the meat quality of pigs Samples of the longissimus lumborum et thoracis muscle from the right half of the carcass of all pigs (12 from each treatment) were removed for analysis. Starting at the posterior end of the longissimus, chops of 25 mm thick, were taken in the following order: 3 chops for chemical composition, 2 chops for pH value, 5 chops for cooking loss and sensory evaluation and 3 chops for color evaluation. All chops were individually vacuum-packed, frozen at 45 C and stored at 25 C until examination. In addition, fat taken from the back of animals’ neck was frozen and stored until examination at 75 C to be used for the fatty acid analysis.
2.1. Experimental design Partial and total replacement of SBM with extruded chickpeas in the meat quality of pigs was studied with 48 weaned crossbred (Landrace · Large White) pigs (53 ± 4 d of age) in a 17 wk study conducted at the National Agricultural Research Foundation (N.AG.RE.F.), Animal Research Institute, in Giannitsa (Greece). On arrival, pigs were individually weighed and randomly allocated to four dietary treatments (ECKP0, ECKP100, ECKP200 and ECKP300) of 12 pigs/treatment and accommodated in 2floor pens/treatment of 6 pigs. All 8 pens were identical, with the same covered area (2 m2/pig), and were equipped with similar troughs for feed concentrates and water. During the experiment, all pigs in the four treatments received two diets (i.e., a grower diet or finisher diet; Table 1) ad libitum; a grower diet from 53 to 94 d of age (growing period), and a finisher diet from 95 to 171 d of age (finishing period), according to NRC (1998) nutrient requirements of pigs. Both diets for ECKP0 treatment had no chickpeas (control), while those for treatments ECKP100, ECKP200 and ECKP300 included 100, 200 and 300 kg/t of extruded chickpeas, respectively. At the end of the experiment, all pigs were fasted for 18 h (water was allowed), weighed and slaughtered. After dressing and storing for 24 h at 3 C, carcasses were weighed according to European Union guidelines (EC, 1993). All pigs used in the experiment were cared for according to applicable recommendations of US National Research Council (NRC, 1996). The chickpeas (variety ‘Serifos’) used in the experiment were obtained from the Fodder Crops and Pasture Institute (N.AG.RE.F.) in Larissa (Greece), and were heat treated to reduce anti-nutritional factors (ANF) by extrusion
2.2.1. Chemical composition of lean meat and pH values Lean meat content evaluation by chemical analysis for moisture, protein, fat and ash was made according to methods 950.46, 981.10, 960.39, and 920.153, respectively, of AOAC (1990). Thirty-six samples (3 chops · 12 pigs) from each treatment were used and mean values were recorded. The measurements of pH were taken with a WTW microprocessor pH-meter (WTW GmbH, Weilheim, Germany). Twenty-four samples (2 chops · 12 pigs) from each treatment were used and mean values were recorded. 2.2.2. Cooking loss Sixty samples (5 chops · 12 pigs) from each treatment were taken from the freezer approximately 24 h before cooking and placed at 4 C for 22–24 h. The day of cooking, chops were unpacked; dried on the surface with cloth towels and weighed; placed on a plastic tray; covered with a plastic bag to prevent surface drying; and held at room temperature up to 20 min prior to cooking. The samples were grilled at 175 C to an internal temperature of 70– 71 C. Internal temperature was monitored using constant copper thermocouples connected to a strip chart recorder (Honeywell Inc., Fort Washington, PA). Samples were turned once at 40 C. The cooked chops were cooled to room temperature, blotted dry and weighed. Percentage cooking loss was determined by dividing the difference in blotted uncooked and cooked weights by the 1/100 of the weight of the blotted sample (uncooked). 2.2.3. Color evaluation Color determination was carried out on the surface of raw thawed samples using a HunterLab Chroma Meter
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Table 1 Concentrate composition of growing (20–50 kg body weight, BW) and finishing (50–120 kg BW) pig diets (as fed basis) Treatmentsa ECKP0
ECKP100
ECKP200
ECKP300
Ingredient composition of growing pig diets (kg/t) Corn grain, ground Barley grain, ground Wheat grain, ground Wheat bran Corn gluten meal (620 g/kg CP) Soybean meal (424 g/kg CP) Chickpeas extruded (239 g/kg CP) Sunflower meal (290 g/kg CP) Vegetable fat L-Lysine monohydrochloride DL-Methionine 990 g/kg Limestone Monocalcium phosphate Salt Vitamin–mineral premixb
250 219.9 100 150 45 160 0 10 25 2 0.1 16 14 4 4
250 175.4 100 150 63 80 100 20 21 2.5 0.1 16 14 4 4
250 120 100 150 78 0 200 40 20 3 0 15 16 4 4
250 51.3 100 150 55 0 300 36 17 1.4 0.3 15 16 4 4
Ingredient composition of finishing pig diets (kg/t) Corn grain, ground Barley grain, ground Wheat grain, ground Wheat bran Com gluten meal (620 g/kg CP) Soybean meal (424 g/kg CP) Chickpeas extruded (239 g/kg CP) Sunflower meal (290 g/kg CP) Vegetable fat L-Lysine monohydrochloride DL-Methionine 990 g/kg Limestone Monocalcium phosphate Salt Vitamin-mineral premixb
250 284.4 100 150 21 120 0 10 26 1.6 0 15 14 4 4
250 241.9 100 140 30 60 100 17 22 1.6 0 14.5 15 4 4
250 197.3 100 120 34 0 200 39 20 1.6 0.1 13.5 16.5 4 4
250 143.2 100 100 11 0 300 40 17 0 0.3 13 17.5 4 4
a
ECKP0, control treatment; ECKP100, treatment with 100 kg/t extruded chickpea; ECKP200, treatment with 200 kg/t extruded chickpea; ECKP300, treatment with 300 kg/t extruded chickpea. b Premix supplied per kg of concentrate: 15,000 I.U. vitamin A; 1 mg vitamin B1; 5 mg vitamin B2; 25 mg niacin; 11 mg pantothenic acid; 0.5 mg vitamin B6; 0.05 mg biotin; 1 mg folic acid; 500 mg choline; 0.015 mg vitamin B12; 10 mg vitamin C; 2,400 I.U. vitamin D3; 15 mg vitamin E; 2 mg vitamin K3; 0.5 mg Co; 15 mg Cu; 3 mg I; 80 mg Fe; 100 mg Mn; 0.3 mg Se; 100 mg Zn, and 60 mg Salinomycin.
(DP-9000 RESTON VIRGINIA USA) equipped with an optical sensor D25. Values of lightness (L*), redness (a*) and yellowness (b*) were measured. Based on a* and b* values, the h value (hue angle: the ratio b*/a*) and the C* value (chroma: (a*2 + b*2)1/2) were calculated as indicators of the intensity of color (Clydesdale, 1998). The means of five measurements made on the upper surface of the three chops of each pig were recorded for each color indicator. Twelve samples from each treatment were used and mean values were recorded for each color indicator. 2.2.4. Sensory evaluation Sensory evaluation was carried out with the chops used for cooking loss determination. A 10 member trained sensory panel was used to evaluate meat for odor and taste, tenderness and juiciness. The number of samples tasted by each ‘‘trained taste panel’’ was four, e.g., one of each treatment and the examination was repeated five times. A preparatory session was held before each panel to discuss
and clarify the attributes to be evaluated. Testing was initiated after the panelists agreed on the specifications. The chops of each treatment were cooked according to the protocol described in cooking loss determination (Section 2.2.2.). They were well done and presented to the panelists in random order after they have been cut into 2 · 2 cm pieces. Water was provided for rinsing of the mouth between samples. Panelists were asked to rate each sample on a scale of 1 through 10 based on odor and taste, tenderness and juiciness. A ‘10’ was considered ‘very pleasant odor and taste’, ‘very tender’, and ‘very juicy’, respectively. A‘1’ was considered ‘weak odor and taste’, ‘very tough’, and ‘very dry’, respectively. Furthermore, an untrained panel of 20 members evaluated cooked meat for overall acceptability on a 10-point hedonic scale (1 = dislike extremely, 10 = like extremely). Panel members were selected from students and staff of the Faculty of Veterinary Medicine. The panelists were instructed to express their evaluation for overall acceptability of cooked pork chops after
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considering the consistency, juiciness and odor and taste of the product. Samples were prepared and offered to the panelists as described for trained panel evaluation. 2.2.5. Fatty acid profile Gas liquid chromatography (GLC) was used to measure the fatty acid composition of the samples. The myristic, palmitic, palmitoleic, stearic, oleic, linoleic, linolenic and arachidonic acids were measured as their corresponding methyl esters following the method of Christie (1989). The GLC operated under the following conditions: 25 m wall coated open tubular (WCOT) column 0.32 mm internal diameter coated with CP-TM-SIL88; helium as the gas carrier (split injection). Initial temperature of the column was 145 C maintained for 4 min followed by a ramp rate of 3 C per min to 160 C. This temperature was maintained for 5 min followed by a ramp rate of 5 C per min to the final temperature of 170 C. The detection temperature was performed by the JCL 6000 Chromatography data system (Maw, Fowler, Hamilton, & Petchey, 2003). Moreover, fatty acid ratios such as ratio of polyunsaturated fatty acids (PUFA) to saturated fatty acids (P:S ratio) were calculated for their potential significance in human nutrition (Enser, Hallet, Hewitt, Fursey, & Wood, 1996, 1998). 2.2.6. Statistical analysis Data collected for chemical composition, pH value, cooking loss, color evaluation, sensory evaluation and fatty acid profile were analyzed by analysis of variance. When the analysis showed significant treatment effects, Fisher’s least significant difference test (LSD0.05) was used to determine mean differences between treatments (Steel & Torrie,
1980). The Kruskal–Wallis non-parametric test was used for the analysis of ordinary levels of the sensory evaluation measurements. All cases from the groups (control and treatments) were combined and ranked and mean ranks were assigned (Siegel, 1956). Data analysis was performed using the SPSS software and all decisions about the acceptance or rejection of a statistical hypothesis were made at the 0.05 level of significance. 3. Results and discussion The slaughter weight of pigs is presented in Table 2. No differences were observed (P > 0.05) among treatments. The replacement of SBM by extruded chickpeas caused a slight increase (P > 0.05) in moisture content of the longissimus lumborum et thoracis muscle; the moisture content being 74.3% for the control group, and ranged between 74.9% and 75.1% for the extruded chickpea groups (Table 2). Results for protein, fat and ash contents of the same muscle indicated no significant differences among treatments (P > 0.05). All the extruded chickpea samples had almost the same protein and fat contents which were about 23.0% and 1.0%, respectively. The control group had a protein content of 23.2% and a fat content of 1.1%. The fat content seems to be low in comparison to measurements taken in other studies (Mason et al., 2005), although some studies gave similar to results (Fernandez, Monin, Talmann, Mourot, & Lebret, 1999). In addition, the replacement of SBM by chickpeas indicated no statistically significant effect on the pH value of the pork meat (P > 0.05, Table 2). The highest mean pH value (5.61) was observed for the control group and the
Table 2 Effect of replacing soybean meal by extruded chickpeas on slaughter weight, chemical composition, physico-chemical properties and color of pork meat Parameters
Slaughter weight, kg
TreatmentsA,B ECKP0
ECKP100
ECKP200
ECKP300
120.9 ± 2.96
116.7 ± 2.75
120.6 ± 1.65
117.9 ± 2.96
Chemical composition Moisture (%) Protein (%) Fat (%) Ash (%)
74.3 ± 0.39a 23.2 ± 0.47a 1.1 ± 0.13a 1.1 ± 0.04a
75.1 ± 0.34a 22.6 ± 0.34a 1.0 ± 0.21a 1.1 ± 0.03a
74.9 ± 0.25a 22.9 ± 0.27a 0.9 ± 0.10a 1.1 ± 0.05a
75.0 ± 0.34a 22.9 ± 0.31a 1.0 ± 0.13a 1.0 ± 0.06a
Physico-chemical properties pH Cooking loss
5.61 ± 0.03a 26.4 ± 0.32a
5.49 ± 0.08a 28.9 ± 0.73b
5.52 ± 0.01a 29.1 ± 0.31b
5.51 ± 0.02a 27.3 ± 0.40b
55.17 ± 0.41a 7.22 ± 0.43a 13.03 ± 0.40a 0.55 ± 0.02a 111.97 ± 8.48a
60.68 ± 1.58b 6.85 ± 0.46a 11.09 ± 0.13b 0.61 ± 0.03ab 85.58 ± 4.12b
58.73(1.22)b 7.03 ± 0.22a 10.28 ± 0.18c 0.68 ± 0.03b 77.80 ± 0.94b
58.50 ± 0.24b 6.67 ± 0.36a 10.18 ± 0.19c 0.65 ± 0.03b 75.58 ± 3.51b
Color Lightness (L*) Yellowness (b*) Redness (a*) Hue Chroma
a–c Means within the same row with different superscript letters are significantly different (P < 0.05) according to Fisher’s least significant difference test (LSD0.05). A ECKP0, control treatment; ECKP100, treatment with 100 kg/t extruded chickpea; ECKP200, treatment with 200 kg/t extruded chickpea; ECKP300, treatment with 300 kg/t extruded chickpea. B Values represent means ± standard error of mean (SE).
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lowest (5.49) for the ECKP100 treatment. The ECKP200 and the ECKP300 treatments resulted in the same pH values of 5.51 (P > 0.05). These ultimate pH values are considered to be relatively low and approaching the pH of PSE meat. However, many authors refer to these values as being normal (Santos-Silva, Bessa, & Santos-Silva, 2002; Wood et al., 2004). Percentages of cooking loss of the ECKP100, ECKP200 and ECKP300 groups were 28.9%, 29.1% and 27.3%, respectively, but these differences were not significant (P > 0.05, Table 2). The control group had a cooking loss of 26.4% which was statistically different from all the experimental groups (P < 0.05, Table 2). This is probably due to some substances in chickpea having a negative effect on water holding capacity (WHC) of lean meat. There is no information regarding the above substances and this could be a subject for further research. Low meat pH is often associated with low WHC and has a high influence on the ability of meat to retain its water during processing, storage and cooking. A low WHC results in high drip and cooking loss and poor eating quality (dryer and tougher in the cooked state). In the present study, a significant negative correlation (P < 0.05) was observed between pH and cooking loss. Furthermore, the ultimate pH value of the control group was slightly higher than those of the extruded chickpea groups and this could explain the cooking loss differences. All color parameters were affected significantly (P < 0.05, Table 2) by treatment except yellowness (b*). The lightness (L*) of the control group was 55.17, while that for the chickpea groups ranged between 58.50 and 60.68. Thus, the replacement of SBM by extruded chickpeas had a significantly increased effect on lean meat lightness. In contrast, no differences were observed in meat lightness between ECKP100, ECKP200 and ECKP300 treatments.
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Furthermore, the redness (a*) was reduced (P < 0.05) when extruded chickpeas were incorporated into the diet. The higher a* values and lower L* values measured in the control samples may be due to the WHC of the meat. The water is blocked and no myoglobin is lost through drip and the proteins are unreflective and so the meat appears darker due to absorption of light (Young & West, 2001). Moreover, the statistically significant higher C* values (P < 0.05) of the control samples indicated that they had a more intensive color than the experimental samples (more distant to the L* axis of the CIELAB system). The lower h* value of the control samples indicated that they were redder than the experimental samples (more distant to the a* axis of the CIE color space). All chickpea samples had the same C* and h* values which indicated that their color has the same redness. The taste panel gave high scores for meat odor and taste, tenderness, and juiciness irrespective of the diet. The odor and taste scores were slightly higher in the control samples, but statistically not significant (P > 0.05, Table 3). No differences were recorded for tenderness, except ECKP200, which was less tender than all the other treatments. ECKP200 and ECKP100 were less juicy than the control and the ECKP300 treatment, which had a slightly lower evaluation for overall acceptability by the untrained panel (P < 0.05, Table 3). Although some studies indicate a positive effect of intramuscular fat level on the sensory attributes of pork (Eikelenboom, Hoving-Bolink, & Van der Wall, 1996; Touraille, Monin, & Legault, 1989), in our experiment the sensory quality of all samples was very good in spite of their low fat content. The quality of fat tissue is known to be an important aspect of carcass quality, both in terms of processing and consumer acceptability (Whittington, Prescott, Wood, & Enser, 1986). Santos-Silva et al. (2002) and Wood et al.
Table 3 Effect of replacing soybean meal by extruded chickpeas on sensory attitudes of pork meat (results of Kruskal–Wallis non-parametric test) Sensory attributes
TreatmentsA ECKP0
ECKP100
ECKP200
ECKP300
Odor and taste Mean ± SEB Mean rank
8.58 ± 0.08a 132.66
8.38 ± 0.08a 112.03
8.46 ± 0.09a 120.16
8.41 ± 0.04a 117.15
Tenderness Mean ± SE Mean rank
8.31 ± 0.11a 139.54
8.11 ± 0.12a 120.88
7.65 ± 0.09b 85.81
8.26 ± 0.08a 135.77
Juiciness Mean ± SE Mean rank
8.41 ± 0.10a 144.21
8.05 ± 0.10b 115.21
7.81 ± 0.81c 96.65
8.18 ± 0.65ab 125.93
Overall acceptability Mean ± SE Mean rank
8.50 ± 0.09a 146.48
8.18 ± 0.09b 117.93
7.86 ± 0.08c 90.45
8.30 ± 0.08ab 127.15
a–c
Means within the same row with different superscript letters are significantly different (P < 0.05) according to Fisher’s least significant difference test (LSD0.05). A ECKP0, control treatment; ECKP100, treatment with 100 kg/t extruded chickpea; ECKP200, treatment with 200 kg/t extruded chickpea; ECKP300, treatment with 300 kg/t extruded chickpea. B SE, standard error of mean.
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Table 4 Effect of replacing soybean meal by extruded chickpeas on fatty acid profile of pork meat (percentage by weight of total fatty acids) Parameters
Treatmentsa,b ECKP0
ECKP100
ECKP200
ECKP300
Fatty acid C14:0 SFA Myristic C16:0 SFA Palmitic C16:1 MUFA Palmitoleic C18:0 SFA Stearic C18:1 MUFA Oleic C18:2 PUFA n 6 Linoleic C18:3 PUFA n 3 Linolenic C20.4 PUFA Arachidonic
2.03 ± 0.47 23.63 ± 1.87 1.80 ± 0.51 18.08 ± 1.52 37.48 ± 1.94 11.98 ± 0.41 0.58 ± 0.14 0.74 ± 0.20
2.80 ± 0.95 24.70 ± 2.55 1.90 ± 0.70 16.33 ± 1.23 37.06 ± 2.64 12.78 ± 1.10 0.72 ± 0.08 0.70 ± 0.12
1.76 ± 0.32 22.75 ± 1.98 1.03 ± 0.08 19.35 ± 2.22 37.31 ± 1.62 13.61 ± 0.66 0.85 ± 0.08 0.88 ± 0.11
1.75 ± 0.31 21.78 ± 1.76 4.01 ± 2.35 16.55 ± 1.13 37.58 ± 2.16 13.21 ± 0.87 1.18 ± 0.38 0.46 ± 0.30
Fatty acid ratios related to human nutrition Total SFA Total MUFA Total PUFA P:Sc
43.74 39.28 13.30 0.287
43.83 38.96 14.20 0.314
43.86 38.34 15.34 0.330
40.08 41.59 14.85 0.359
a ECKP0, control treatment; ECKP100, treatment with 100 kg/t extruded chickpea; ECKP200, treatment with 200 kg/t extruded chickpea; ECKP300, treatment with 300 kg/t extruded chickpea. b Values represent means ± standard error of mean (SE). c P:S is C18:2n6þC18:3n3 C12:0þC14:0þC16:0 .
(2003) found that the fatty acid composition is related to differences in organoleptic attributes, especially in the flavor of lamb meat. Previous studies also indicated that the fatty acid composition of longisimus luborum muscle was related to the eating quality of pork with saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) being positively correlated with pork flavor and polyunsaturated fatty acids (PUFA) being negatively correlated (Cameron & Enser, 1991). In addition, it is well known that the fatty acid profile of pork fat can be changed by feeding diets high in particular fatty acids (Wood et al., 2004). In our experiments the feeding of pigs with chickpeas did not significantly affect (P > 0.05) the fatty acid profile of the pork (Table 4). More specifically, the total percentage of SFAs, MUFAs and PUFAs of the control group were 43.74%, 39.28% and 13.30%, respectively. The corresponding percentages of the experimental groups were 43.83%, 38.96% and 14.20% (ECKPIOO), 43.86%, 38.34% and 15.34% (ECKP200), and 40.08%, 41.59% and 14.85% (ECKP300). Moreover, the ratios of importance to human nutrition indicated a decrease in SFAs and an increase in MUFAs in the ECKP300 group, although these differences were not statistically significant and did not influence the taste. In addition, the P:S level of the chickpea samples almost reached the level of 0.45, recommended from earlier studies (Department of Health & Social Security, 1984). Similar figures regarding the fatty acid profile of the pork was also found by other researchers (Corino et al., 2002; Piedrafita, Christian, & Lonergan, 2001; Wood et al., 2004).
as odor and taste, tenderness and juiciness, indicated some small differences between dietary treatments containing extruded chickpeas up to 300 kg/t compared to a control group containing soybean meal. The replacement of soybean meal by extruded chickpeas in the diets of growing– finishing pigs reduced the redness of the lean meat, increased loss during cooking and had a negative effect on the juiciness and overall acceptability of the meat in the ECKP100 and ECKP200 treatments. However, the fact that the ECKP300 had the same sensory attributes as the control, indicate that the small differences in color and WHC, are of less importance and are not necessarily caused by chickpea inclusion in the diets of the pigs. Since pig performance, carcass classification, slaughter weight and other important meat quality attributes like odor and taste, fatty acid composition remained the same in all experimental groups; extruded chickpeas could be an alternative protein source to soybean meal in the diets of growing–finishing pigs.
4. Conclusions
AOAC (Association of Official Analytical Chemists). (1990). Official Methods of Analysis of the AOAC. In K. Helrich (Ed.), (15th ed.). Arlington, VA, USA. Batterham, E. S., Saini, H. S., Andersen, L. M., & Baigent, R. D. (1993). Tolerance of growing pigs to trypsin and chymotrypsin inhibitors in
Physical characteristics of the pork, such as pH, color and cooking loss, as well as sensory characteristics, such
Acknowledgements This research was funded by a Greek and Czech Government bilateral exchange program. The authors thank the staff of Animal Research Institute, N.AG.RE.F. (Giannitsa, Greece), and especially Mr. P. Mitrentzis, for help he provided during this study, and ELVIZ S.A. (Plati Imathias, Greece) for extrusion of chickpeas. References
V. Christodoulou et al. / Meat Science 73 (2006) 529–535 chickpeas (Cicer arietinum) and pigeonpeas (Cajanus cajari). Journal of the Science of Food and Agriculture, 61, 211–216. Cameron, D. N., & Enser, M. (1991). Fatty acid composition of lipid in longissimus dorsi muscle of Duroc and British Landrasse pigs and its relationship with eating quality. Meat Science, 29, 295–307. Cazarin, A., Bravo, F., de Uriarte, L. A., & Shimada, A. (1976). Tecnologia Pecuaria Mexicana, 31, 27. Cheeke, P. R. (1999). Applied animal nutrition: Feeds and feeding (2nd ed.). NJ, USA: Prentice Hall. Christie, W. W. (1989). Gas chromatography and lipids. A practical guide. Ayr, UK: The oily Press. Christodoulou, V., Bampidis, V. A., Sossidou, E., Ambrosiadis, J., Hucˇko, B., Iliadis, C., et al. (accepted). The use of extruded chickpeas in diets for growing–finishing pigs. Szech Journal of Animal Science. Clydesdale, M. F. (1998). Color: origin, stability, measurement and quality. In A. T. Irwin & R. P. Singh (Eds.), Food storage stability (pp. 175–190). Boca Raton/Boston/London/NY/Washington DC, USA: CRC Press. Corino, C., Magni, S., Pagliarini, E., Rossi, R., Pastorelli, G., & Chiesa, L. M. (2002). Effect of dietary fats on meat quality and characteristics of heavy pig loins. Meat Science, 60, 1–8. Department of Health and Social Security. (1984). Report on Health and Social Subjects No. 46. Nutritional aspects of cardiovascular disease. London, UK: HMSO. EC. (1993). Council Regulation (EC) No. 3513/93 of 14 December 1993 amending Regulation (EEC) No. 3220/84 determining the Community scale for grading pig carcases (pp. 5–6). Official Journal L 320, 22.12.1993. Eikelenboom, G., Hoving-Bolink, A. H., & Van der Wall, P. G. (1996). The eating quality of pork. 2. The influence of intramuscular fat. Fleischwirtschaft, 76, 559–560. Enser, M., Hallet, K., Hewitt, B., Fursey, G. A. J., & Wood, J. D. (1996). Fatty acid content and composition of English beef, lamb and pork in retail. Meat Science, 42, 443–456. Enser, M., Hallett, K. G., Hewett, B., Fursey, A. J., Wood, J. D., & Harrington, G. (1998). Fatty acid content and composition of UK beef and lamb muscle in relation to production system and implications for human nutrition. Meat Science, 49, 329–341. FAO (Food and Agriculture Organization) (1993) (pp. 105–115). FAO yearbook. Production 1992 (Vol. 46). Rome, Italy: FAO. Fernandez, X., Monin, G., Talmann, A., Mourot, J., & Lebret, B. (1999). Influence of intramuscular fat content on the quality of pig meat-I. Composition of the lipid traction and sensory characteristics of m. longissimus luborum. Meat Science, 53, 59–65. Friedman, M. (1996). Nutritional value of proteins from different food sources. A review. Journal of Agricultural and Food Chemistry, 44, 6–29. Iliadis, C. (2001). Evaluation of six chickpea varieties for seed yield under autumn and spring sowing. Journal of Agricultural Science, Cambridge, 137, 439–444. Mason, L. M., Hogan, S. A., Lynch, A., Sullivan, K. O., Lawlor, P. G., & Kerry, J. D. (2005). Effect of restricted feeding and antioxidant supplementation on pig performance and quality characteristics of longisimus dorsi muscle from Landrasse and Duroc pigs. Meat Science, 70, 307–317.
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Maw, S. J., Fowler, V. L., Hamilton, M., & Petchey, A. M. (2003). Physical characteristics of pig fat and their relation to fatty acid composition. Meat Science, 63, 185–190. Mustafa, A. F., Thacker, P. A., McKinnon, J. J., Christensen, D. A., & Racz, V. J. (2000). Nutritional value of feed grade chickpeas for ruminants and pigs. Journal of the Science of Food and Agriculture, 80, 1581–1588. National Research Council (1996). Guide for the care and use of laboratory animals. Washington, DC, USA: National Academy Press. National Research Council (1998). Nutrient Requirements of Swine (10th rev. ed.). Washington, DC, USA: National Academy Press. Piedrafita, J., Christian, L. L., & Lonergan, S. M. (2001). Fatty acid profiles in three stress genotypes of swine and relationships with performance, carcass and meat quality traits. Meat Science, 57, 71–77. Santos-Silva, J., Bessa, R. J. B., & Santos-Silva, F. (2002). Effect of genotype, feeding system slaughter weight on quality of light lambs. II Fatty acid composition of meat. Livestock Production Science, 77, 187–194. Siegel, S. (1956). Non-pararametric statistics for the behavioral sciences. Tokyo, Japan: McGraw-Hill Kogakusha. Shimada, A. S., & Brambila, S. (1967). Tecnologia Pecuaria Mexicana 9, 27; 10, 5, 19. Steel, R. G. D., & Torrie, J. H. (1980). Principles and procedures of Statistics. A biometrical approach (2nd ed.). New York, NY, USA: McGraw-Hill Book Co.. Touraille, C., Monin, G., & Legault, C. (1989). Eating quality of meat from European · Chinese crossbred pigs. Meat Science, 25, 177–186. Van der Poel, A. F. B. (1989). Effects of processing on antinutritional factors (ANF) and nutritional value of legume seeds for non-ruminant feeding. In J. Huisman, T. F. B. Van der Poel, & I. E. Liener (Eds.), Recent advances of research in antinutritional factors in legume seeds (pp. 213–229). Wageningen, The Netherlands: Pudoc. Vooijs, A. J., Beumer, H., & Van der Poel, A. F. B. (1993). Evaluation of heat treatments to improve the protein digestibility of Phaseolus vulgaris beans in pigs. In A. F. B. Van der Poel, J. Huisman, & H. S. Saini (Eds.), Recent advances of research in antinutritional factors in legume seeds (pp. 473–476). Wageningen, The Netherlands: Wageningen Pers. Whittington, F. M., Prescott, N. J., Wood, J. D., & Enser, M. (1986). The effect of dietary linoleic-acid on the firmness of backfat in pigs of 85 kg live weight. Journal of the Science of Food and Agriculture, 37, 753–761. Wood, J. D., Nute, G. R., Richarson, R. I., Whittington, F. M., Southwood, O., Plastow, G., et al. (2004). Effects of breed, diet and muscle on fat deposition and eating quality in pigs. Meat Science, 67, 651–667. Wood, J. D., Richarson, R. I., Nute, G. R., Fisher, A. V., Campo, M. M., Kasapidou, E., et al. (2003). Effects of fatty acids on meat quality. Meat Science, 66, 21–32. Young, O. A., & West, J. (2001). Meat color. In Y. H. Hui, Wai-Kit Nip, R. W. Rogers, & O. A. Young (Eds.), Meat science and applications (pp. 63). New York/Basel: Marcel Decker Inc.. Zamora, J. M., Aguirre, A., Shimada, A., & Martinez, L. (1975). Tecnologia Pecuaria Mexicana, 28, 40.
Effect of replacing soybean meal by extruded chickpeas in the diets of growing–finishing pigs on meat quality Vladimiros Christodoulou a, John Ambrosiadis b,*, Evangelia Sossidou a, Vasileios Bampidis a, John Arkoudilos c, Borris Hucko d, Constantin Iliadis b
e
a National Agricultural Research Foundation (N.AG.RE.F.), Animal Research Institute, 58100 Giannitsa, Greece Aristotle University of Thessaloniki, Faculty of Veterinary Medicine, Laboratory of Technology of Animal Origin Food, 54124 Thessaloniki, Greece c N.AG.RE.F., Institute of Technology of Agricultural Products, 14123 Athens, Greece d University of Agriculture, Agronomic Faculty, Department of Animal Nutrition, 16521 Prague 6-Suchdol, Czech Republic e N.AG.RE.F., Fodder Crops and Pasture Institute, 41335 Larissa, Greece
Received 1 August 2005; received in revised form 8 February 2006; accepted 8 February 2006
Abstract The main objective of this study was to evaluate the effect of the replacement of soybean meal by extruded chickpeas in diets of growing–finishing pigs on meat quality. In a 17 wk study 48 growing–finishing crossbred pigs were fed ad libitum. The experimental design included four treatments, each one of 12 pigs; the ECKP0 treatment was fed with diet containing soybean meal and no chickpeas (control), while treatments ECKP100, ECKP200 and ECKP300 were fed with diets containing 100, 200 and 300 kg/t of extruded chickpeas, respectively. The lean meat quality of the longissimus lumborum et thoracis muscle was evaluated by chemical analysis (moisture, protein, fat and ash), fatty acid profile, pH measurement, cooking loss, color evaluation, and sensory evaluation. Odor and taste, tenderness, juiciness, and overall acceptability were scored on 1–10 scales by a group of 10 experienced assessors after a standard cooking regime. Small differences were observed between control and experimental groups in chemical composition (P > 0.05). Fatty acid profiles, pH measurements and color evaluation did not differ among treatments (P > 0.05), while cooking loss was significantly lower in the control group (P < 0.05). The taste panel gave slightly higher scores for the tenderness and juiciness for the control group compared with the chickpea treatments (P < 0.05). No differences were observed between control and experimental groups in taste scores (P > 0.05). It is concluded that the replacement of soybean meal by extruded chickpeas, when substituted isonitrogenously and isoenergetically at inclusion levels up to 300 kg/t of pig, does not influence significantly meat quality. 2006 Elsevier Ltd. All rights reserved. Keywords: Chickpeas; Extrusion; Pigs; Meat quality
1. Introduction Recently, research on the replacement of soybean meal (SBM) with other protein and energy sources in farm animals’ diets became of major financial importance in most European countries. The reason is that the majority of raw soy supplies in Europe are imported from non-European countries. The chickpea (Cicer arietinum L.) is one of the world’s most important grain legumes (FAO, 1993). In *
Corresponding author. Tel.: +30 2310 999814; fax: +30 2310 999812. E-mail address: [email protected] (J. Ambrosiadis).
0309-1740/$ - see front matter 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.meatsci.2006.02.008
Mediterranean countries, it is cultivated principally as a legume crop, since it is well adapted to semi-arid conditions, with some irrigated varieties yielding as much as 3.5 t/ha of seed in autumn seedings (Iliadis, 2001). Although most chickpeas are produced for human consumption, they provide the livestock industry with an alternative protein and energy feedstuff. Shimada and Brambila (1967), in a series of three experiments, studied the chickpea as a source of both protein and energy for the growing pig indicating that the raw chickpea supplied adequate protein, energy, and amino acids to support satisfactory growth and efficiency of feed utilization, even when chickpea meal supplied the
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major portion of the diet. Zamora, Aguirre, Shimada, and Martinez (1975) Cazarin, Bravo, de Uriarte, and Shimada (1976) have shown that chickpeas can completely replace SBM in practical sorghum–SBM diets for growing–finishing pigs without affecting pig performance or carcass quality. Friedman (1996) described chickpea protein quality as being equivalent to that of SBM and chickpeas have been reported to be suitable as a protein concentrate for pigs (Batterham, Saini, Andersen, & Baigent, 1993; Mustafa, Thacker, McKinnon, Christensen, & Racz, 2000). More recently, Christodoulou et al. (accepted) showed that partial and total replacement of SBM with extruded chickpeas, at inclusion levels up to 300 kg/t of concentrate mixture, as the main protein source in growing pig diets resulted in similar productive traits for the full growing/finishing period. Although the effect of chickpea inclusion in pig diets on growth performance is well established, there is little information about the meat quality produced by its use. The aim of the present study was to investigate the effect of the replacement of SBM by chickpeas in diets of growing–finishing pigs on the pork quality. 2. Materials and methods
(Cheeke, 1999). In preparation for extrusion, chickpeas were ground to pass a 2 mm screen using a hammer mill. Ground chickpeas were extruded at 120 C (i.e., barrel temperature near exit) for 20 s using a Berga model ME-103 extruder (Berga, Impianti Cereali S.p.A., Treviso, Italy). The extruded chickpeas were reground to pass a 2 mm screen before mixing into the diets. The combination of process temperature and heating time used was based on reports of Van der Poel (1989) and Vooijs et al. (1993). 2.2. Evaluation of the meat quality of pigs Samples of the longissimus lumborum et thoracis muscle from the right half of the carcass of all pigs (12 from each treatment) were removed for analysis. Starting at the posterior end of the longissimus, chops of 25 mm thick, were taken in the following order: 3 chops for chemical composition, 2 chops for pH value, 5 chops for cooking loss and sensory evaluation and 3 chops for color evaluation. All chops were individually vacuum-packed, frozen at 45 C and stored at 25 C until examination. In addition, fat taken from the back of animals’ neck was frozen and stored until examination at 75 C to be used for the fatty acid analysis.
2.1. Experimental design Partial and total replacement of SBM with extruded chickpeas in the meat quality of pigs was studied with 48 weaned crossbred (Landrace · Large White) pigs (53 ± 4 d of age) in a 17 wk study conducted at the National Agricultural Research Foundation (N.AG.RE.F.), Animal Research Institute, in Giannitsa (Greece). On arrival, pigs were individually weighed and randomly allocated to four dietary treatments (ECKP0, ECKP100, ECKP200 and ECKP300) of 12 pigs/treatment and accommodated in 2floor pens/treatment of 6 pigs. All 8 pens were identical, with the same covered area (2 m2/pig), and were equipped with similar troughs for feed concentrates and water. During the experiment, all pigs in the four treatments received two diets (i.e., a grower diet or finisher diet; Table 1) ad libitum; a grower diet from 53 to 94 d of age (growing period), and a finisher diet from 95 to 171 d of age (finishing period), according to NRC (1998) nutrient requirements of pigs. Both diets for ECKP0 treatment had no chickpeas (control), while those for treatments ECKP100, ECKP200 and ECKP300 included 100, 200 and 300 kg/t of extruded chickpeas, respectively. At the end of the experiment, all pigs were fasted for 18 h (water was allowed), weighed and slaughtered. After dressing and storing for 24 h at 3 C, carcasses were weighed according to European Union guidelines (EC, 1993). All pigs used in the experiment were cared for according to applicable recommendations of US National Research Council (NRC, 1996). The chickpeas (variety ‘Serifos’) used in the experiment were obtained from the Fodder Crops and Pasture Institute (N.AG.RE.F.) in Larissa (Greece), and were heat treated to reduce anti-nutritional factors (ANF) by extrusion
2.2.1. Chemical composition of lean meat and pH values Lean meat content evaluation by chemical analysis for moisture, protein, fat and ash was made according to methods 950.46, 981.10, 960.39, and 920.153, respectively, of AOAC (1990). Thirty-six samples (3 chops · 12 pigs) from each treatment were used and mean values were recorded. The measurements of pH were taken with a WTW microprocessor pH-meter (WTW GmbH, Weilheim, Germany). Twenty-four samples (2 chops · 12 pigs) from each treatment were used and mean values were recorded. 2.2.2. Cooking loss Sixty samples (5 chops · 12 pigs) from each treatment were taken from the freezer approximately 24 h before cooking and placed at 4 C for 22–24 h. The day of cooking, chops were unpacked; dried on the surface with cloth towels and weighed; placed on a plastic tray; covered with a plastic bag to prevent surface drying; and held at room temperature up to 20 min prior to cooking. The samples were grilled at 175 C to an internal temperature of 70– 71 C. Internal temperature was monitored using constant copper thermocouples connected to a strip chart recorder (Honeywell Inc., Fort Washington, PA). Samples were turned once at 40 C. The cooked chops were cooled to room temperature, blotted dry and weighed. Percentage cooking loss was determined by dividing the difference in blotted uncooked and cooked weights by the 1/100 of the weight of the blotted sample (uncooked). 2.2.3. Color evaluation Color determination was carried out on the surface of raw thawed samples using a HunterLab Chroma Meter
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Table 1 Concentrate composition of growing (20–50 kg body weight, BW) and finishing (50–120 kg BW) pig diets (as fed basis) Treatmentsa ECKP0
ECKP100
ECKP200
ECKP300
Ingredient composition of growing pig diets (kg/t) Corn grain, ground Barley grain, ground Wheat grain, ground Wheat bran Corn gluten meal (620 g/kg CP) Soybean meal (424 g/kg CP) Chickpeas extruded (239 g/kg CP) Sunflower meal (290 g/kg CP) Vegetable fat L-Lysine monohydrochloride DL-Methionine 990 g/kg Limestone Monocalcium phosphate Salt Vitamin–mineral premixb
250 219.9 100 150 45 160 0 10 25 2 0.1 16 14 4 4
250 175.4 100 150 63 80 100 20 21 2.5 0.1 16 14 4 4
250 120 100 150 78 0 200 40 20 3 0 15 16 4 4
250 51.3 100 150 55 0 300 36 17 1.4 0.3 15 16 4 4
Ingredient composition of finishing pig diets (kg/t) Corn grain, ground Barley grain, ground Wheat grain, ground Wheat bran Com gluten meal (620 g/kg CP) Soybean meal (424 g/kg CP) Chickpeas extruded (239 g/kg CP) Sunflower meal (290 g/kg CP) Vegetable fat L-Lysine monohydrochloride DL-Methionine 990 g/kg Limestone Monocalcium phosphate Salt Vitamin-mineral premixb
250 284.4 100 150 21 120 0 10 26 1.6 0 15 14 4 4
250 241.9 100 140 30 60 100 17 22 1.6 0 14.5 15 4 4
250 197.3 100 120 34 0 200 39 20 1.6 0.1 13.5 16.5 4 4
250 143.2 100 100 11 0 300 40 17 0 0.3 13 17.5 4 4
a
ECKP0, control treatment; ECKP100, treatment with 100 kg/t extruded chickpea; ECKP200, treatment with 200 kg/t extruded chickpea; ECKP300, treatment with 300 kg/t extruded chickpea. b Premix supplied per kg of concentrate: 15,000 I.U. vitamin A; 1 mg vitamin B1; 5 mg vitamin B2; 25 mg niacin; 11 mg pantothenic acid; 0.5 mg vitamin B6; 0.05 mg biotin; 1 mg folic acid; 500 mg choline; 0.015 mg vitamin B12; 10 mg vitamin C; 2,400 I.U. vitamin D3; 15 mg vitamin E; 2 mg vitamin K3; 0.5 mg Co; 15 mg Cu; 3 mg I; 80 mg Fe; 100 mg Mn; 0.3 mg Se; 100 mg Zn, and 60 mg Salinomycin.
(DP-9000 RESTON VIRGINIA USA) equipped with an optical sensor D25. Values of lightness (L*), redness (a*) and yellowness (b*) were measured. Based on a* and b* values, the h value (hue angle: the ratio b*/a*) and the C* value (chroma: (a*2 + b*2)1/2) were calculated as indicators of the intensity of color (Clydesdale, 1998). The means of five measurements made on the upper surface of the three chops of each pig were recorded for each color indicator. Twelve samples from each treatment were used and mean values were recorded for each color indicator. 2.2.4. Sensory evaluation Sensory evaluation was carried out with the chops used for cooking loss determination. A 10 member trained sensory panel was used to evaluate meat for odor and taste, tenderness and juiciness. The number of samples tasted by each ‘‘trained taste panel’’ was four, e.g., one of each treatment and the examination was repeated five times. A preparatory session was held before each panel to discuss
and clarify the attributes to be evaluated. Testing was initiated after the panelists agreed on the specifications. The chops of each treatment were cooked according to the protocol described in cooking loss determination (Section 2.2.2.). They were well done and presented to the panelists in random order after they have been cut into 2 · 2 cm pieces. Water was provided for rinsing of the mouth between samples. Panelists were asked to rate each sample on a scale of 1 through 10 based on odor and taste, tenderness and juiciness. A ‘10’ was considered ‘very pleasant odor and taste’, ‘very tender’, and ‘very juicy’, respectively. A‘1’ was considered ‘weak odor and taste’, ‘very tough’, and ‘very dry’, respectively. Furthermore, an untrained panel of 20 members evaluated cooked meat for overall acceptability on a 10-point hedonic scale (1 = dislike extremely, 10 = like extremely). Panel members were selected from students and staff of the Faculty of Veterinary Medicine. The panelists were instructed to express their evaluation for overall acceptability of cooked pork chops after
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considering the consistency, juiciness and odor and taste of the product. Samples were prepared and offered to the panelists as described for trained panel evaluation. 2.2.5. Fatty acid profile Gas liquid chromatography (GLC) was used to measure the fatty acid composition of the samples. The myristic, palmitic, palmitoleic, stearic, oleic, linoleic, linolenic and arachidonic acids were measured as their corresponding methyl esters following the method of Christie (1989). The GLC operated under the following conditions: 25 m wall coated open tubular (WCOT) column 0.32 mm internal diameter coated with CP-TM-SIL88; helium as the gas carrier (split injection). Initial temperature of the column was 145 C maintained for 4 min followed by a ramp rate of 3 C per min to 160 C. This temperature was maintained for 5 min followed by a ramp rate of 5 C per min to the final temperature of 170 C. The detection temperature was performed by the JCL 6000 Chromatography data system (Maw, Fowler, Hamilton, & Petchey, 2003). Moreover, fatty acid ratios such as ratio of polyunsaturated fatty acids (PUFA) to saturated fatty acids (P:S ratio) were calculated for their potential significance in human nutrition (Enser, Hallet, Hewitt, Fursey, & Wood, 1996, 1998). 2.2.6. Statistical analysis Data collected for chemical composition, pH value, cooking loss, color evaluation, sensory evaluation and fatty acid profile were analyzed by analysis of variance. When the analysis showed significant treatment effects, Fisher’s least significant difference test (LSD0.05) was used to determine mean differences between treatments (Steel & Torrie,
1980). The Kruskal–Wallis non-parametric test was used for the analysis of ordinary levels of the sensory evaluation measurements. All cases from the groups (control and treatments) were combined and ranked and mean ranks were assigned (Siegel, 1956). Data analysis was performed using the SPSS software and all decisions about the acceptance or rejection of a statistical hypothesis were made at the 0.05 level of significance. 3. Results and discussion The slaughter weight of pigs is presented in Table 2. No differences were observed (P > 0.05) among treatments. The replacement of SBM by extruded chickpeas caused a slight increase (P > 0.05) in moisture content of the longissimus lumborum et thoracis muscle; the moisture content being 74.3% for the control group, and ranged between 74.9% and 75.1% for the extruded chickpea groups (Table 2). Results for protein, fat and ash contents of the same muscle indicated no significant differences among treatments (P > 0.05). All the extruded chickpea samples had almost the same protein and fat contents which were about 23.0% and 1.0%, respectively. The control group had a protein content of 23.2% and a fat content of 1.1%. The fat content seems to be low in comparison to measurements taken in other studies (Mason et al., 2005), although some studies gave similar to results (Fernandez, Monin, Talmann, Mourot, & Lebret, 1999). In addition, the replacement of SBM by chickpeas indicated no statistically significant effect on the pH value of the pork meat (P > 0.05, Table 2). The highest mean pH value (5.61) was observed for the control group and the
Table 2 Effect of replacing soybean meal by extruded chickpeas on slaughter weight, chemical composition, physico-chemical properties and color of pork meat Parameters
Slaughter weight, kg
TreatmentsA,B ECKP0
ECKP100
ECKP200
ECKP300
120.9 ± 2.96
116.7 ± 2.75
120.6 ± 1.65
117.9 ± 2.96
Chemical composition Moisture (%) Protein (%) Fat (%) Ash (%)
74.3 ± 0.39a 23.2 ± 0.47a 1.1 ± 0.13a 1.1 ± 0.04a
75.1 ± 0.34a 22.6 ± 0.34a 1.0 ± 0.21a 1.1 ± 0.03a
74.9 ± 0.25a 22.9 ± 0.27a 0.9 ± 0.10a 1.1 ± 0.05a
75.0 ± 0.34a 22.9 ± 0.31a 1.0 ± 0.13a 1.0 ± 0.06a
Physico-chemical properties pH Cooking loss
5.61 ± 0.03a 26.4 ± 0.32a
5.49 ± 0.08a 28.9 ± 0.73b
5.52 ± 0.01a 29.1 ± 0.31b
5.51 ± 0.02a 27.3 ± 0.40b
55.17 ± 0.41a 7.22 ± 0.43a 13.03 ± 0.40a 0.55 ± 0.02a 111.97 ± 8.48a
60.68 ± 1.58b 6.85 ± 0.46a 11.09 ± 0.13b 0.61 ± 0.03ab 85.58 ± 4.12b
58.73(1.22)b 7.03 ± 0.22a 10.28 ± 0.18c 0.68 ± 0.03b 77.80 ± 0.94b
58.50 ± 0.24b 6.67 ± 0.36a 10.18 ± 0.19c 0.65 ± 0.03b 75.58 ± 3.51b
Color Lightness (L*) Yellowness (b*) Redness (a*) Hue Chroma
a–c Means within the same row with different superscript letters are significantly different (P < 0.05) according to Fisher’s least significant difference test (LSD0.05). A ECKP0, control treatment; ECKP100, treatment with 100 kg/t extruded chickpea; ECKP200, treatment with 200 kg/t extruded chickpea; ECKP300, treatment with 300 kg/t extruded chickpea. B Values represent means ± standard error of mean (SE).
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lowest (5.49) for the ECKP100 treatment. The ECKP200 and the ECKP300 treatments resulted in the same pH values of 5.51 (P > 0.05). These ultimate pH values are considered to be relatively low and approaching the pH of PSE meat. However, many authors refer to these values as being normal (Santos-Silva, Bessa, & Santos-Silva, 2002; Wood et al., 2004). Percentages of cooking loss of the ECKP100, ECKP200 and ECKP300 groups were 28.9%, 29.1% and 27.3%, respectively, but these differences were not significant (P > 0.05, Table 2). The control group had a cooking loss of 26.4% which was statistically different from all the experimental groups (P < 0.05, Table 2). This is probably due to some substances in chickpea having a negative effect on water holding capacity (WHC) of lean meat. There is no information regarding the above substances and this could be a subject for further research. Low meat pH is often associated with low WHC and has a high influence on the ability of meat to retain its water during processing, storage and cooking. A low WHC results in high drip and cooking loss and poor eating quality (dryer and tougher in the cooked state). In the present study, a significant negative correlation (P < 0.05) was observed between pH and cooking loss. Furthermore, the ultimate pH value of the control group was slightly higher than those of the extruded chickpea groups and this could explain the cooking loss differences. All color parameters were affected significantly (P < 0.05, Table 2) by treatment except yellowness (b*). The lightness (L*) of the control group was 55.17, while that for the chickpea groups ranged between 58.50 and 60.68. Thus, the replacement of SBM by extruded chickpeas had a significantly increased effect on lean meat lightness. In contrast, no differences were observed in meat lightness between ECKP100, ECKP200 and ECKP300 treatments.
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Furthermore, the redness (a*) was reduced (P < 0.05) when extruded chickpeas were incorporated into the diet. The higher a* values and lower L* values measured in the control samples may be due to the WHC of the meat. The water is blocked and no myoglobin is lost through drip and the proteins are unreflective and so the meat appears darker due to absorption of light (Young & West, 2001). Moreover, the statistically significant higher C* values (P < 0.05) of the control samples indicated that they had a more intensive color than the experimental samples (more distant to the L* axis of the CIELAB system). The lower h* value of the control samples indicated that they were redder than the experimental samples (more distant to the a* axis of the CIE color space). All chickpea samples had the same C* and h* values which indicated that their color has the same redness. The taste panel gave high scores for meat odor and taste, tenderness, and juiciness irrespective of the diet. The odor and taste scores were slightly higher in the control samples, but statistically not significant (P > 0.05, Table 3). No differences were recorded for tenderness, except ECKP200, which was less tender than all the other treatments. ECKP200 and ECKP100 were less juicy than the control and the ECKP300 treatment, which had a slightly lower evaluation for overall acceptability by the untrained panel (P < 0.05, Table 3). Although some studies indicate a positive effect of intramuscular fat level on the sensory attributes of pork (Eikelenboom, Hoving-Bolink, & Van der Wall, 1996; Touraille, Monin, & Legault, 1989), in our experiment the sensory quality of all samples was very good in spite of their low fat content. The quality of fat tissue is known to be an important aspect of carcass quality, both in terms of processing and consumer acceptability (Whittington, Prescott, Wood, & Enser, 1986). Santos-Silva et al. (2002) and Wood et al.
Table 3 Effect of replacing soybean meal by extruded chickpeas on sensory attitudes of pork meat (results of Kruskal–Wallis non-parametric test) Sensory attributes
TreatmentsA ECKP0
ECKP100
ECKP200
ECKP300
Odor and taste Mean ± SEB Mean rank
8.58 ± 0.08a 132.66
8.38 ± 0.08a 112.03
8.46 ± 0.09a 120.16
8.41 ± 0.04a 117.15
Tenderness Mean ± SE Mean rank
8.31 ± 0.11a 139.54
8.11 ± 0.12a 120.88
7.65 ± 0.09b 85.81
8.26 ± 0.08a 135.77
Juiciness Mean ± SE Mean rank
8.41 ± 0.10a 144.21
8.05 ± 0.10b 115.21
7.81 ± 0.81c 96.65
8.18 ± 0.65ab 125.93
Overall acceptability Mean ± SE Mean rank
8.50 ± 0.09a 146.48
8.18 ± 0.09b 117.93
7.86 ± 0.08c 90.45
8.30 ± 0.08ab 127.15
a–c
Means within the same row with different superscript letters are significantly different (P < 0.05) according to Fisher’s least significant difference test (LSD0.05). A ECKP0, control treatment; ECKP100, treatment with 100 kg/t extruded chickpea; ECKP200, treatment with 200 kg/t extruded chickpea; ECKP300, treatment with 300 kg/t extruded chickpea. B SE, standard error of mean.
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Table 4 Effect of replacing soybean meal by extruded chickpeas on fatty acid profile of pork meat (percentage by weight of total fatty acids) Parameters
Treatmentsa,b ECKP0
ECKP100
ECKP200
ECKP300
Fatty acid C14:0 SFA Myristic C16:0 SFA Palmitic C16:1 MUFA Palmitoleic C18:0 SFA Stearic C18:1 MUFA Oleic C18:2 PUFA n 6 Linoleic C18:3 PUFA n 3 Linolenic C20.4 PUFA Arachidonic
2.03 ± 0.47 23.63 ± 1.87 1.80 ± 0.51 18.08 ± 1.52 37.48 ± 1.94 11.98 ± 0.41 0.58 ± 0.14 0.74 ± 0.20
2.80 ± 0.95 24.70 ± 2.55 1.90 ± 0.70 16.33 ± 1.23 37.06 ± 2.64 12.78 ± 1.10 0.72 ± 0.08 0.70 ± 0.12
1.76 ± 0.32 22.75 ± 1.98 1.03 ± 0.08 19.35 ± 2.22 37.31 ± 1.62 13.61 ± 0.66 0.85 ± 0.08 0.88 ± 0.11
1.75 ± 0.31 21.78 ± 1.76 4.01 ± 2.35 16.55 ± 1.13 37.58 ± 2.16 13.21 ± 0.87 1.18 ± 0.38 0.46 ± 0.30
Fatty acid ratios related to human nutrition Total SFA Total MUFA Total PUFA P:Sc
43.74 39.28 13.30 0.287
43.83 38.96 14.20 0.314
43.86 38.34 15.34 0.330
40.08 41.59 14.85 0.359
a ECKP0, control treatment; ECKP100, treatment with 100 kg/t extruded chickpea; ECKP200, treatment with 200 kg/t extruded chickpea; ECKP300, treatment with 300 kg/t extruded chickpea. b Values represent means ± standard error of mean (SE). c P:S is C18:2n6þC18:3n3 C12:0þC14:0þC16:0 .
(2003) found that the fatty acid composition is related to differences in organoleptic attributes, especially in the flavor of lamb meat. Previous studies also indicated that the fatty acid composition of longisimus luborum muscle was related to the eating quality of pork with saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) being positively correlated with pork flavor and polyunsaturated fatty acids (PUFA) being negatively correlated (Cameron & Enser, 1991). In addition, it is well known that the fatty acid profile of pork fat can be changed by feeding diets high in particular fatty acids (Wood et al., 2004). In our experiments the feeding of pigs with chickpeas did not significantly affect (P > 0.05) the fatty acid profile of the pork (Table 4). More specifically, the total percentage of SFAs, MUFAs and PUFAs of the control group were 43.74%, 39.28% and 13.30%, respectively. The corresponding percentages of the experimental groups were 43.83%, 38.96% and 14.20% (ECKPIOO), 43.86%, 38.34% and 15.34% (ECKP200), and 40.08%, 41.59% and 14.85% (ECKP300). Moreover, the ratios of importance to human nutrition indicated a decrease in SFAs and an increase in MUFAs in the ECKP300 group, although these differences were not statistically significant and did not influence the taste. In addition, the P:S level of the chickpea samples almost reached the level of 0.45, recommended from earlier studies (Department of Health & Social Security, 1984). Similar figures regarding the fatty acid profile of the pork was also found by other researchers (Corino et al., 2002; Piedrafita, Christian, & Lonergan, 2001; Wood et al., 2004).
as odor and taste, tenderness and juiciness, indicated some small differences between dietary treatments containing extruded chickpeas up to 300 kg/t compared to a control group containing soybean meal. The replacement of soybean meal by extruded chickpeas in the diets of growing– finishing pigs reduced the redness of the lean meat, increased loss during cooking and had a negative effect on the juiciness and overall acceptability of the meat in the ECKP100 and ECKP200 treatments. However, the fact that the ECKP300 had the same sensory attributes as the control, indicate that the small differences in color and WHC, are of less importance and are not necessarily caused by chickpea inclusion in the diets of the pigs. Since pig performance, carcass classification, slaughter weight and other important meat quality attributes like odor and taste, fatty acid composition remained the same in all experimental groups; extruded chickpeas could be an alternative protein source to soybean meal in the diets of growing–finishing pigs.
4. Conclusions
AOAC (Association of Official Analytical Chemists). (1990). Official Methods of Analysis of the AOAC. In K. Helrich (Ed.), (15th ed.). Arlington, VA, USA. Batterham, E. S., Saini, H. S., Andersen, L. M., & Baigent, R. D. (1993). Tolerance of growing pigs to trypsin and chymotrypsin inhibitors in
Physical characteristics of the pork, such as pH, color and cooking loss, as well as sensory characteristics, such
Acknowledgements This research was funded by a Greek and Czech Government bilateral exchange program. The authors thank the staff of Animal Research Institute, N.AG.RE.F. (Giannitsa, Greece), and especially Mr. P. Mitrentzis, for help he provided during this study, and ELVIZ S.A. (Plati Imathias, Greece) for extrusion of chickpeas. References
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