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Sensory attributes and texture profile of beef burgers with gari
Meat Science 92 (2012) 745–748
Contents lists available at SciVerse ScienceDirect
Meat Science journal homepage: www.elsevier.com/locate/meatsci
Sensory attributes and texture profile of beef burgers with gari W.Y. Akwetey ⁎, C.L. Knipe The Ohio State University, Columbus, OH, USA
a r t i c l e
i n f o
Article history: Received 16 August 2011 Received in revised form 18 June 2012 Accepted 19 June 2012 Keywords: Gari Beef burger Springiness Gumminess Chewiness Comminuted meat
a b s t r a c t Beef burgers were produced using gari to substitute beef in the product formulations at 0% (control), 10%, 15% and 20% respectively. Cooking yield increased significantly (p b 0.05) with increasing use of gari. Sensory evaluation of the products revealed significant (p b 0.05) differences for acceptability and texture attributes. The acceptability score for burgers produced with 15% gari was not significantly different (p > 0.05) from the control without gari. Using gari had no significant (p > 0.05) effect on flavor and odor attributes of beef burgers. Texture profile analysis of burgers showed significant (p b 0.05) reductions in hardness, springiness, gumminess and chewiness at all levels of substituting beef with gari. Production cost of burgers reduced by 9%, 14% and 18% respectively using 10%, 15% and 20% gari in burgers. The results suggest that gari has promising potential for use in comminuted meat products. © 2012 Elsevier Ltd. All rights reserved.
1. Introduction The consumption of processed meats including beef burgers is the preserve of “the minority few” in Ghana who are considered “well to do” because the vast majority are unable to afford the relatively high prices of such products in Ghana as well as in many other developing countries. Meat processors should therefore be encouraged to provide a wider variety of products which meet consumer acceptance at affordable prices in order to increase the consumption of processed meats in developing nations. This necessitates a search for reduced formulation cost procedures while not compromising the quality and sensory attributes of the products. Several non-meat ingredients are currently used as extenders in processed meats in different parts of the world, at regulated levels to provide variety, improve sensory characteristics, enhance shelf stability, reduce production costs and enhance profitability. Meat extenders have been defined as non-meat ingredients which are added to low quality meat products for economic reasons (FAO, 1990). The list of ingredients investigated as meat extenders and or substitutes includes cereal grains (Beggs, Bowers, & Brown, 1997; Skrede, 1989), dairy sources (Atughonu, Zayas, Herald, & Harbers, 1998), fruits and vegetables (Aleson-Carbonell, Fernandez-Lopez, Sayas-Barbera, & Perez-Alvarez, 2003; Revilla & Quintana, 2005), legumes (Dzudie, Scher,
& Hardy, 2002; Hinds, 2001; Lin, Huff, & Hsieh, 2000; Lin & Mei, 2000; Muguerza, Ansorena, & Astiasaran, 2003; Rossi, 1988), roots and tubers (Annor-Frempong, Annang-Prah, & Wiredu, 1996; Kao & Lin, 2006), and single-cell sources (Bruna, Fernandez, Hierro, De La Hoz, & Ordonez, 1999; Bruna et al., 2003; Lin & Lin, 2004). Annor-Frempong et al. (1996) used cassava flour as a substitute to fat in comminuted pork sausages and reported that 9% of cassava flour could be used in place of fat without any compromise on organoleptic quality. Gari is a precooked product obtained from cassava root processing in most West African countries, including Ghana. It has a relatively high water-binding capability and forms a consistent mass when hydrated and subjected to heat. Its potential for use as a meat extender or substitute is however yet to be elucidated. Therefore the objective of this study was to assess the potential of using gari as partial substitute to ground beef. The specific objectives were to determine: • an optimum level of hydrated gari as a meat extender in beef burgers • effects of using hydrated gari on product yields and costs of production, • texture profile and consumer acceptability of the resultant beef burgers. 2. Materials and methods 2.1. Raw materials and production of beef burgers
⁎ Corresponding author at: College of Agriculture and Natural Resources, Department of Animal Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. Tel.: +233 273 854 766; fax: +233 322 060 137. E-mail addresses: [email protected] (W.Y. Akwetey), [email protected] (C.L. Knipe). 0309-1740/$ – see front matter © 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.meatsci.2012.06.032
Frozen beef (24.21% fat) was obtained from the Meat Laboratory at The Ohio State University, and gari was obtained from Ghana through the Berekum Market (Columbus, Ohio). Four treatments, namely control (0%, i.e. no gari), 10%, 15% and 20% each of hydrated gari replaced ground beef (w/w) in the formulations for the beef
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burgers. The beef was ground through 8 mm plate using a Hobart grinder (Troy, OH). The gari used was pre-hydrated with distilled water in a ratio of 1:3 (w/w) because a preliminary investigation to assess the water binding potential of gari indicated that this is the ideal ratio. Mixing was done 15 min after water was added to the gari. A commercial food mixer (Holly 100 mixer, Hollymatic Corporation, Countryside, IL) was used and the mixing for each treatment lasted 3 min. The resulting mix of gari and ground beef was finally ground through a 5 mm plate and formed into patties. A mechanized patty former (Hollymatic 8/65 Multiflow Pattie Maker, Countryside, IL) was used to ensure uniform sizing of the burgers. Beef burgers were stored in a freezer at − 18 °C overnight, and vacuum packaged for frozen storage and further analysis. A roll stock vacuum machine (Ulma Packaging Machine, Guipuzcoa, Spain) was used for packaging. The four treatments were replicated three times. 2.2. Parameters measured 2.2.1. Cooking yield and costs of production Beef burgers were weighed before and after final cooking to an internal temperature of 73.8 °C, and cooking yield was determined as a percentage of final to initial weight. Cooking Yield ð% Þ ¼ ðfinal weight 100Þ=ðinitial weightÞ: The costs of producing beef burgers with and without using gari were calculated based on the prevailing market retail prices of gari and ground beef at Columbus, OH. 2.2.2. Texture profile analysis (TPA) After cooking the beef burgers to an internal temperature of 73.8 °C, cylindrical samples measuring 9 mm in height×19 mm in diameter were taken from the center and used for the TPA. An Instron 5542 Texture Analyzer, (Instron Co., Canton, MA, USA) was used at a double compression rate of 0.5 mm/s. The equipment measured hardness, springiness, gumminess, chewiness, adhesiveness and cohesiveness of the products as defined by Bourne (1978). 2.3. Sensory evaluation A 9-point Hedonic scale was used to assess the acceptability of the cooked beef burgers at the OSU Sensory Laboratory. In all, one hundred and fifty consumers assessed the beef burgers. The criteria used were: overall acceptability, flavor, texture and odor desirability on a scale of 1 to 9, where 9 represented “like extremely” and 1 represented “dislike extremely.” Samples were blind coded with random three-digit numbers and the order of serving samples was randomized so that each sample occurred equally. Fifty panelists participated in each of three sessions of the evaluation process. Panelists comprised students and staff of the Departments of Food Science and Technology and Animal Sciences, OSU. Beef burgers were grilled at a temperature of 176 °C using George Foreman Grilling Machine (Lake Forest, IL) to achieve cooked internal temperatures of 73.8 °C, and randomly served to the panelists. The internal temperature of the burgers was monitored using a 12-channel thermocouple scanning thermometer (model 92000-00) (Eutech Instruments Pte Ltd., Singapore). Water and crackers were served to rinse and eat between tasting samples. Approval to use human subjects for the sensory panel evaluation was granted by the Office of Responsible Research Practices (ORRP), OSU. 2.4. Statistical analysis A one-factor, Completely Randomized Design (CRD), involving four different levels of hydrated gari in beef burgers, was used. These resulted in four experimental units comprising 0% (control, no gari added), 10%, 15% and 20% of hydrated gari, respectively coded as GT0, GT10, GT15
and GT20. Preliminary statistical analysis of the data showed no significant differences (p>0.05) among the treatment replicates. All data generated from the study were therefore pooled, and subjected to Analysis of Variance (ANOVA) using SPSS (2006) version 15.0.1 for Windows. Significant differences between means (p b 0.05) were determined using Scheffé Multiple Comparison. 3. Results and discussion 3.1. Cooking yield, sensory attributes and costs of producing beef burgers The cooking yield, sensory attributes and production costs for using gari as partial substitute to ground beef in beef burgers are shown in Table 1. Substituting ground beef with hydrated gari improved the cooking yields of beef burgers at all levels of use. These yields were significantly different (p b 0.05) with increasing level of hydrated gari in the burger formulations compared to the control. The yields of both GT 15 and GT 20 were significantly higher (p b 0.05) than the yields for GT 0 and GT 10. The presence of gari in the product formulations resulted in increased moisture absorption during production. Consequently, higher moisture was retained in the beef burgers containing hydrated gari due to improved water holding capacity during cooking, and thus the observed higher yields, since the control treatment without gari resulted in significantly (p b 0.5) lower yields, compared to all the other treatments. These findings are in agreement with those of Annor-Frempong et al. (1996) and Dzudie et al. (2002). Annor-Frempong et al. (1996) reported that the carbohydrate in cassava aided moisture retention when cassava flour was used in pork sausages leading to higher cooking yields. Sensory evaluation of the beef burgers revealed significantly different (p b 0.05) values for overall product acceptability and texture (Table 1). The control product, GT 10 and GT 15 were equally acceptable to the panel members. Although a higher overall acceptability score was attributed for GT 10, this score was not significantly different (p > 0.05) from the control and GT 15. Also the acceptability for GT 20 was significantly (p b 0.05) lower compared to GT 10. The GT 20 burgers became too soft (at the 20% level of using hydrated gari). In fact the TPA revealed that hardness of the beef burgers was significantly lower (p b 0.05) at 20% gari inclusion level (Table 2). The use of hydrated gari in the beef burger formulations influenced product texture significantly (p b 0.05). Texture attribute scores improved from 5.86 (control) to 6.51 at the 10% level of gari usage, and reduced thereafter to 5.41 when 20% of beef was replaced with hydrated gari (Table 1). It would seem that the threshold level for using gari to improve the texture attribute of beef burgers was exceeded after 10% beef was replaced with hydrated gari. Consequently, the overall product acceptability was lower for GT20 compared to GT10 (Table 1). Although some panelists commented about “rancid flavor” in GT 20, generally, no significant differences (p > 0.05) were obtained for product flavor (Table 1). The similarity in flavor attributes scored by the consumers was due to the fact that no salts were added to the Table 1 Cooking yield, acceptability attributes and production cost of beef burgers (±standard error). Parameter
Treatment GT0
Cooking yield (%) Overall liking Texture Flavor Odor Production cost ($/kg)
GT10 a
67.86 ±1.13 6.08ab ±0.17 5.86ab ± 0.22 5.95a ± 0.17 5.88a ± 0.16 4.40
GT15 b
72.23 ± 0.96 6.57b ± 0.14 6.51b ± 0.16 6.35a ± 0.16 6.17a ± 0.14 4.00
GT20 c
76.10 ± 0.76 6.12ab ± 0.17 6.17ab ± 0.20 6.05a ± 0.17 6.03a ± 0.15 3.81
77.61c ± 0.48 5.57a ± 0.18 5.41a ± 0.20 5.70a ± 0.18 5.84a ± 0.15 3.61
Values are means of triplicates; abcmeans in same row with different superscripts are significantly different (p b 0.05). Sensory attributes were scored for “like extremely” = 9 to “dislike extremely” = 1; GT0 (control, no gari added); GT10, GT15 and GT20 respectively, had 10%, 15% and 20% hydrated gari substituted for ground beef.
W.Y. Akwetey, C.L. Knipe / Meat Science 92 (2012) 745–748
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Table 2 Texture profile analysis of cooked beef burgers (±standard error). Treatment
Texture profile Har (N)
0
GT GT10 GT15 GT20
d
2.38 ± 0.13 1.59c ± 0.11 1.13b ± 0.05 0.63a ± 0.04
Spr (mm) c
3.32 ± 0.02 2.99b ± 0.02 2.80a ± 0.02 2.71a ± 0.03
Gum (N) d
14.57 ± 0.61 8.15c ± 0.44 5.09b ± 0.15 3.15a ± 0.15
Che (J) d
65.38 ± 2.72 36.57c ± 1.98 22.84b ± 0.68 14.13a ± 0.65
Adh (Ns × −10−5) abc
4.0 ± 0.00 8.0ab ± 0.00 8.0ab ± 0.00 2.0c ± 0.00
Coh 0.65c ± 0.01 0.54b ± 0.01 0.48a ± 0.02 0.52ab ± 0.01
abcd Means with different superscripts in the same column are significantly different (p > 0.05); GT0 (control, no added gari); GT10, GT15 and GT20 respectively, had 10%, 15% and 20% hydrated gari substituted for beef. Har = hardness; Spr = springiness; Gum = gumminess; Che = chewiness; Adh = adhesiveness; Coh = cohesiveness.
beef burger formulations to influence flavor intensities. A protein– carbohydrate interaction probably during cooking was perhaps mistaken by some panel members for a “rancid flavor” in GT 20. According to Rodriguez-Saona, (personal communication) protein and carbohydrates react during heat treatment to produce flavors that could be mistaken for rancid flavor. The odor of beef burgers was also not significantly influenced (p > 0.05) by the use of gari in the formulations. In fact, the general observation among the panel members suggested a slight improvement in flavor and odor desirability up to 10% of added hydrated gari though these differences were not significantly different (p > 0.05) compared to the control (Table 2). Economic analysis of ingredients used, and output of burgers resulted in $4.40, $4.00, $3.81 and $3.61 per kg respectively for beef burgers produced with 0%, 10%, 15% and 20% of hydrated gari in place of beef (Table 1). Thus 9%, 14% and 18% of production costs per kg were saved respectively using gari in burger formulations. These savings on cost of production could be shared with consumers by reducing the sale price of the beef burgers in order to encourage their consumption. 3.2. Texture profile analyses (TPA) of beef burgers Hardness, springiness, gumminess, chewiness, and cohesiveness of the beef burgers reduced significantly (p b 0.05) with increasing use of gari in the formulations (Table 2). The control treatment was significantly (p b 0.05) harder, springier, gummier, more chewy and cohesive compared to all the formulations with added hydrated gari. This is an indication that compared to the control, the use of gari in the burgers aided in moisture absorption and retention in the products during cooking. Hence, water holding capacity of burgers containing hydrated gari will increase with increasing levels of gari. Annor-Frempong et al. (1996) reported that the carbohydrate in cassava aided moisture retention in sausages formulated with cassava flour. Consumers nowadays prefer beef burgers that are less gummy, not hard, less springy and cohesive, and easy to chew because harder, gummier and chewy burgers mean more time wasted in masticating and completing a beef burger meal. Hardness reduced significantly (p b 0.05) from 2.38 (GT 0) to 0.63 (GT 20) while springiness ranged from 3.32 (GT 0) to 2.71 (GT 20). Gumminess and chewiness were reduced from 14.57 to 3.15 and 65.38 to 14.13 for GT 0 and GT 20, respectively. The adhesiveness of the beef burgers ranged from 2.0 × 10 − 5 (GT 20) to 8.0 × 10 − 5 (GT 10 and GT 15) when 10% and 15%, respectively, of beef were replaced with gari; but the control product, GT 10 and GT 15 were not significantly different (p > 0.05). However, replacing ground beef in burgers with more than 15% gari resulted in a significant increase (p b 0.05) in adhesiveness. Thus, the minimum work necessary to pull the compressing plunger on the Instron equipment away from the sample tended to reduce initially with the use of gari as an extender in beef burgers. But above 15% gari substitution for beef in the formulations, this force increased considerably. However the adhesiveness of GT 0 (control) and GT 20 were not significantly different (p > 0.05) compared to GT 10 and GT 20. Since the
cooking yields of the burgers were higher above 15% of inclusion, it is deduced that more water was retained in the burgers with more than 15% gari compared to all other levels of gari substitution, and this resulted in very soft beef burgers (Table 2).
4. Conclusions and recommendations The cooking yields of beef burgers increased with increasing usage of gari as an extender. Furthermore, using gari in beef burgers led to significant improvements in the overall consumer acceptability of the products and there were significant improvements in the texture profile as well. The flavor and odor acceptability of all the cooked products were however not statistically affected by the use of gari in the formulations. Adding gari resulted in reduced hardness, springiness, gumminess, chewiness and cohesiveness of beef burgers. Thus, gari has promise for use in meat products. It is concluded that hydrated gari could be used in beef burger formulations at the 10% level of beef substitution without compromising overall product acceptability. It is recommended that further investigations be conducted to ascertain the effect of using gari in other types of comminuted meats, including sausages. Shelf life studies and nutrient composition (protein, fat, ash and moisture) of such products should be established in future studies.
References Aleson-Carbonell, L., Fernandez-Lopez, J., Sayas-Barbera, E., & Perez-Alvarez, J. A. (2003). Utilisation of lemon albedo in dry-cured sausages. Journal of Food Science, 68, 1826–1830. Annor-Frempong, I. E., Annang-Prah, A., & Wiredu, R. (1996). Cassava as non-conventional filler in comminuted meat products. Meat Science, 44, 193–202. Atughonu, A. G., Zayas, J. F., Herald, T. J., & Harbers, L. H. (1998). Thermo-rheology, quality characteristics, and microstructure of frankfurters prepared with selected plant and milk additives. Journal of Food Quality, 21, 223–238. Beggs, K. L. H., Bowers, J. A., & Brown, D. (1997). Sensory and physical characteristics of reduced-fat turkey frankfurters with modified corn starch and water. Journal of Food Science, 62, 1240–1244. Bourne, M. C. (1978). Texture profile analysis. Food Technology, 32, 62–72. Bruna, J. M., Fernandez, M., Hierro, E., De La Hoz, L., & Ordonez, J. A. (1999). Effect of the combined use of Pronase E and Fungal Extract (Mucor racemosus forma sphaerosporus) on the ripening of dry fermented sausages. Food Science and Technology International, 5, 327–337. Bruna, J. M., Hierro, E. M., De La Hoz, L., Mottram, D. S., Fernandez, M., & Ordonez, J. A. (2003). Changes in selected biochemical and sensory parameters as affected by the superficial inoculation of Penicillium camemberti on dry fermented sausages. International Journal of Food Microbiology, 85, 111–125. Dzudie, T., Scher, J., & Hardy, J. (2002). Common bean flour as an extender in beef sausages. Journal of Food Engineering, 52, 143–147. FAO (1990). Manual on simple methods of meat preservation. Animal Production and Health Paper No. 79 (pp. 25–61). Rome. Hinds, M. J. (2001). Sensory and physical quality of soy-based patties. Poster presented at 62nd IFT annual meeting, 23–27 June, 2001, New Orleans, USA. Kao, W. T., & Lin, K. W. (2006). Quality of reduced-fat frankfurter modified by konjac–starch mixed gels. Journal of Food Science, 71, 326–332. Lin, S., Huff, H. E., & Hsieh, F. (2000). Texture and chemical characteristics of soy protein meat analog extruded at high moisture. Journal of Food Science, 65, 264–269. Lin, K. W., & Lin, H. Y. (2004). Quality characteristics of Chinese-style meatball containing bacterial cellulose (Nata). Journal of Food Science, 69, 107–111. Lin, K. -W., & Mei, M. -Y. (2000). Influences of gums, soy protein isolate, and heating temperatures on reduced-fat meat batters in a model system. Journal of Food Science, 65, 48–52.
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Muguerza, E., Ansorena, D., & Astiasaran, I. (2003). Improvement of nutritional properties of chorizo de Pamplona by replacement of pork backfat with soy oil. Meat Science, 65, 1361–1367. Revilla, I., & Quintana, A. M. V. (2005). The effect of different paprika types on the ripening process and quality of dry sausages. International Journal of Food Science and Technology, 40, 411–417. Rossi, M. (1988). Textured sunflower protein for use as meat extender. Labensmittel-Wssen-Schaft-Und-Technologie, 21, 267–270.
Skrede, G. (1989). Characteristics of cooked sausages influenced by potato flour, corn and wheat starches and tapioca. Meat Science, 25, 21–25. SPSS (2006). Statistical Package for Social Sciences, version 15.0.1 for Windows. USA: Microsoft Inc.
Contents lists available at SciVerse ScienceDirect
Meat Science journal homepage: www.elsevier.com/locate/meatsci
Sensory attributes and texture profile of beef burgers with gari W.Y. Akwetey ⁎, C.L. Knipe The Ohio State University, Columbus, OH, USA
a r t i c l e
i n f o
Article history: Received 16 August 2011 Received in revised form 18 June 2012 Accepted 19 June 2012 Keywords: Gari Beef burger Springiness Gumminess Chewiness Comminuted meat
a b s t r a c t Beef burgers were produced using gari to substitute beef in the product formulations at 0% (control), 10%, 15% and 20% respectively. Cooking yield increased significantly (p b 0.05) with increasing use of gari. Sensory evaluation of the products revealed significant (p b 0.05) differences for acceptability and texture attributes. The acceptability score for burgers produced with 15% gari was not significantly different (p > 0.05) from the control without gari. Using gari had no significant (p > 0.05) effect on flavor and odor attributes of beef burgers. Texture profile analysis of burgers showed significant (p b 0.05) reductions in hardness, springiness, gumminess and chewiness at all levels of substituting beef with gari. Production cost of burgers reduced by 9%, 14% and 18% respectively using 10%, 15% and 20% gari in burgers. The results suggest that gari has promising potential for use in comminuted meat products. © 2012 Elsevier Ltd. All rights reserved.
1. Introduction The consumption of processed meats including beef burgers is the preserve of “the minority few” in Ghana who are considered “well to do” because the vast majority are unable to afford the relatively high prices of such products in Ghana as well as in many other developing countries. Meat processors should therefore be encouraged to provide a wider variety of products which meet consumer acceptance at affordable prices in order to increase the consumption of processed meats in developing nations. This necessitates a search for reduced formulation cost procedures while not compromising the quality and sensory attributes of the products. Several non-meat ingredients are currently used as extenders in processed meats in different parts of the world, at regulated levels to provide variety, improve sensory characteristics, enhance shelf stability, reduce production costs and enhance profitability. Meat extenders have been defined as non-meat ingredients which are added to low quality meat products for economic reasons (FAO, 1990). The list of ingredients investigated as meat extenders and or substitutes includes cereal grains (Beggs, Bowers, & Brown, 1997; Skrede, 1989), dairy sources (Atughonu, Zayas, Herald, & Harbers, 1998), fruits and vegetables (Aleson-Carbonell, Fernandez-Lopez, Sayas-Barbera, & Perez-Alvarez, 2003; Revilla & Quintana, 2005), legumes (Dzudie, Scher,
& Hardy, 2002; Hinds, 2001; Lin, Huff, & Hsieh, 2000; Lin & Mei, 2000; Muguerza, Ansorena, & Astiasaran, 2003; Rossi, 1988), roots and tubers (Annor-Frempong, Annang-Prah, & Wiredu, 1996; Kao & Lin, 2006), and single-cell sources (Bruna, Fernandez, Hierro, De La Hoz, & Ordonez, 1999; Bruna et al., 2003; Lin & Lin, 2004). Annor-Frempong et al. (1996) used cassava flour as a substitute to fat in comminuted pork sausages and reported that 9% of cassava flour could be used in place of fat without any compromise on organoleptic quality. Gari is a precooked product obtained from cassava root processing in most West African countries, including Ghana. It has a relatively high water-binding capability and forms a consistent mass when hydrated and subjected to heat. Its potential for use as a meat extender or substitute is however yet to be elucidated. Therefore the objective of this study was to assess the potential of using gari as partial substitute to ground beef. The specific objectives were to determine: • an optimum level of hydrated gari as a meat extender in beef burgers • effects of using hydrated gari on product yields and costs of production, • texture profile and consumer acceptability of the resultant beef burgers. 2. Materials and methods 2.1. Raw materials and production of beef burgers
⁎ Corresponding author at: College of Agriculture and Natural Resources, Department of Animal Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. Tel.: +233 273 854 766; fax: +233 322 060 137. E-mail addresses: [email protected] (W.Y. Akwetey), [email protected] (C.L. Knipe). 0309-1740/$ – see front matter © 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.meatsci.2012.06.032
Frozen beef (24.21% fat) was obtained from the Meat Laboratory at The Ohio State University, and gari was obtained from Ghana through the Berekum Market (Columbus, Ohio). Four treatments, namely control (0%, i.e. no gari), 10%, 15% and 20% each of hydrated gari replaced ground beef (w/w) in the formulations for the beef
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burgers. The beef was ground through 8 mm plate using a Hobart grinder (Troy, OH). The gari used was pre-hydrated with distilled water in a ratio of 1:3 (w/w) because a preliminary investigation to assess the water binding potential of gari indicated that this is the ideal ratio. Mixing was done 15 min after water was added to the gari. A commercial food mixer (Holly 100 mixer, Hollymatic Corporation, Countryside, IL) was used and the mixing for each treatment lasted 3 min. The resulting mix of gari and ground beef was finally ground through a 5 mm plate and formed into patties. A mechanized patty former (Hollymatic 8/65 Multiflow Pattie Maker, Countryside, IL) was used to ensure uniform sizing of the burgers. Beef burgers were stored in a freezer at − 18 °C overnight, and vacuum packaged for frozen storage and further analysis. A roll stock vacuum machine (Ulma Packaging Machine, Guipuzcoa, Spain) was used for packaging. The four treatments were replicated three times. 2.2. Parameters measured 2.2.1. Cooking yield and costs of production Beef burgers were weighed before and after final cooking to an internal temperature of 73.8 °C, and cooking yield was determined as a percentage of final to initial weight. Cooking Yield ð% Þ ¼ ðfinal weight 100Þ=ðinitial weightÞ: The costs of producing beef burgers with and without using gari were calculated based on the prevailing market retail prices of gari and ground beef at Columbus, OH. 2.2.2. Texture profile analysis (TPA) After cooking the beef burgers to an internal temperature of 73.8 °C, cylindrical samples measuring 9 mm in height×19 mm in diameter were taken from the center and used for the TPA. An Instron 5542 Texture Analyzer, (Instron Co., Canton, MA, USA) was used at a double compression rate of 0.5 mm/s. The equipment measured hardness, springiness, gumminess, chewiness, adhesiveness and cohesiveness of the products as defined by Bourne (1978). 2.3. Sensory evaluation A 9-point Hedonic scale was used to assess the acceptability of the cooked beef burgers at the OSU Sensory Laboratory. In all, one hundred and fifty consumers assessed the beef burgers. The criteria used were: overall acceptability, flavor, texture and odor desirability on a scale of 1 to 9, where 9 represented “like extremely” and 1 represented “dislike extremely.” Samples were blind coded with random three-digit numbers and the order of serving samples was randomized so that each sample occurred equally. Fifty panelists participated in each of three sessions of the evaluation process. Panelists comprised students and staff of the Departments of Food Science and Technology and Animal Sciences, OSU. Beef burgers were grilled at a temperature of 176 °C using George Foreman Grilling Machine (Lake Forest, IL) to achieve cooked internal temperatures of 73.8 °C, and randomly served to the panelists. The internal temperature of the burgers was monitored using a 12-channel thermocouple scanning thermometer (model 92000-00) (Eutech Instruments Pte Ltd., Singapore). Water and crackers were served to rinse and eat between tasting samples. Approval to use human subjects for the sensory panel evaluation was granted by the Office of Responsible Research Practices (ORRP), OSU. 2.4. Statistical analysis A one-factor, Completely Randomized Design (CRD), involving four different levels of hydrated gari in beef burgers, was used. These resulted in four experimental units comprising 0% (control, no gari added), 10%, 15% and 20% of hydrated gari, respectively coded as GT0, GT10, GT15
and GT20. Preliminary statistical analysis of the data showed no significant differences (p>0.05) among the treatment replicates. All data generated from the study were therefore pooled, and subjected to Analysis of Variance (ANOVA) using SPSS (2006) version 15.0.1 for Windows. Significant differences between means (p b 0.05) were determined using Scheffé Multiple Comparison. 3. Results and discussion 3.1. Cooking yield, sensory attributes and costs of producing beef burgers The cooking yield, sensory attributes and production costs for using gari as partial substitute to ground beef in beef burgers are shown in Table 1. Substituting ground beef with hydrated gari improved the cooking yields of beef burgers at all levels of use. These yields were significantly different (p b 0.05) with increasing level of hydrated gari in the burger formulations compared to the control. The yields of both GT 15 and GT 20 were significantly higher (p b 0.05) than the yields for GT 0 and GT 10. The presence of gari in the product formulations resulted in increased moisture absorption during production. Consequently, higher moisture was retained in the beef burgers containing hydrated gari due to improved water holding capacity during cooking, and thus the observed higher yields, since the control treatment without gari resulted in significantly (p b 0.5) lower yields, compared to all the other treatments. These findings are in agreement with those of Annor-Frempong et al. (1996) and Dzudie et al. (2002). Annor-Frempong et al. (1996) reported that the carbohydrate in cassava aided moisture retention when cassava flour was used in pork sausages leading to higher cooking yields. Sensory evaluation of the beef burgers revealed significantly different (p b 0.05) values for overall product acceptability and texture (Table 1). The control product, GT 10 and GT 15 were equally acceptable to the panel members. Although a higher overall acceptability score was attributed for GT 10, this score was not significantly different (p > 0.05) from the control and GT 15. Also the acceptability for GT 20 was significantly (p b 0.05) lower compared to GT 10. The GT 20 burgers became too soft (at the 20% level of using hydrated gari). In fact the TPA revealed that hardness of the beef burgers was significantly lower (p b 0.05) at 20% gari inclusion level (Table 2). The use of hydrated gari in the beef burger formulations influenced product texture significantly (p b 0.05). Texture attribute scores improved from 5.86 (control) to 6.51 at the 10% level of gari usage, and reduced thereafter to 5.41 when 20% of beef was replaced with hydrated gari (Table 1). It would seem that the threshold level for using gari to improve the texture attribute of beef burgers was exceeded after 10% beef was replaced with hydrated gari. Consequently, the overall product acceptability was lower for GT20 compared to GT10 (Table 1). Although some panelists commented about “rancid flavor” in GT 20, generally, no significant differences (p > 0.05) were obtained for product flavor (Table 1). The similarity in flavor attributes scored by the consumers was due to the fact that no salts were added to the Table 1 Cooking yield, acceptability attributes and production cost of beef burgers (±standard error). Parameter
Treatment GT0
Cooking yield (%) Overall liking Texture Flavor Odor Production cost ($/kg)
GT10 a
67.86 ±1.13 6.08ab ±0.17 5.86ab ± 0.22 5.95a ± 0.17 5.88a ± 0.16 4.40
GT15 b
72.23 ± 0.96 6.57b ± 0.14 6.51b ± 0.16 6.35a ± 0.16 6.17a ± 0.14 4.00
GT20 c
76.10 ± 0.76 6.12ab ± 0.17 6.17ab ± 0.20 6.05a ± 0.17 6.03a ± 0.15 3.81
77.61c ± 0.48 5.57a ± 0.18 5.41a ± 0.20 5.70a ± 0.18 5.84a ± 0.15 3.61
Values are means of triplicates; abcmeans in same row with different superscripts are significantly different (p b 0.05). Sensory attributes were scored for “like extremely” = 9 to “dislike extremely” = 1; GT0 (control, no gari added); GT10, GT15 and GT20 respectively, had 10%, 15% and 20% hydrated gari substituted for ground beef.
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Table 2 Texture profile analysis of cooked beef burgers (±standard error). Treatment
Texture profile Har (N)
0
GT GT10 GT15 GT20
d
2.38 ± 0.13 1.59c ± 0.11 1.13b ± 0.05 0.63a ± 0.04
Spr (mm) c
3.32 ± 0.02 2.99b ± 0.02 2.80a ± 0.02 2.71a ± 0.03
Gum (N) d
14.57 ± 0.61 8.15c ± 0.44 5.09b ± 0.15 3.15a ± 0.15
Che (J) d
65.38 ± 2.72 36.57c ± 1.98 22.84b ± 0.68 14.13a ± 0.65
Adh (Ns × −10−5) abc
4.0 ± 0.00 8.0ab ± 0.00 8.0ab ± 0.00 2.0c ± 0.00
Coh 0.65c ± 0.01 0.54b ± 0.01 0.48a ± 0.02 0.52ab ± 0.01
abcd Means with different superscripts in the same column are significantly different (p > 0.05); GT0 (control, no added gari); GT10, GT15 and GT20 respectively, had 10%, 15% and 20% hydrated gari substituted for beef. Har = hardness; Spr = springiness; Gum = gumminess; Che = chewiness; Adh = adhesiveness; Coh = cohesiveness.
beef burger formulations to influence flavor intensities. A protein– carbohydrate interaction probably during cooking was perhaps mistaken by some panel members for a “rancid flavor” in GT 20. According to Rodriguez-Saona, (personal communication) protein and carbohydrates react during heat treatment to produce flavors that could be mistaken for rancid flavor. The odor of beef burgers was also not significantly influenced (p > 0.05) by the use of gari in the formulations. In fact, the general observation among the panel members suggested a slight improvement in flavor and odor desirability up to 10% of added hydrated gari though these differences were not significantly different (p > 0.05) compared to the control (Table 2). Economic analysis of ingredients used, and output of burgers resulted in $4.40, $4.00, $3.81 and $3.61 per kg respectively for beef burgers produced with 0%, 10%, 15% and 20% of hydrated gari in place of beef (Table 1). Thus 9%, 14% and 18% of production costs per kg were saved respectively using gari in burger formulations. These savings on cost of production could be shared with consumers by reducing the sale price of the beef burgers in order to encourage their consumption. 3.2. Texture profile analyses (TPA) of beef burgers Hardness, springiness, gumminess, chewiness, and cohesiveness of the beef burgers reduced significantly (p b 0.05) with increasing use of gari in the formulations (Table 2). The control treatment was significantly (p b 0.05) harder, springier, gummier, more chewy and cohesive compared to all the formulations with added hydrated gari. This is an indication that compared to the control, the use of gari in the burgers aided in moisture absorption and retention in the products during cooking. Hence, water holding capacity of burgers containing hydrated gari will increase with increasing levels of gari. Annor-Frempong et al. (1996) reported that the carbohydrate in cassava aided moisture retention in sausages formulated with cassava flour. Consumers nowadays prefer beef burgers that are less gummy, not hard, less springy and cohesive, and easy to chew because harder, gummier and chewy burgers mean more time wasted in masticating and completing a beef burger meal. Hardness reduced significantly (p b 0.05) from 2.38 (GT 0) to 0.63 (GT 20) while springiness ranged from 3.32 (GT 0) to 2.71 (GT 20). Gumminess and chewiness were reduced from 14.57 to 3.15 and 65.38 to 14.13 for GT 0 and GT 20, respectively. The adhesiveness of the beef burgers ranged from 2.0 × 10 − 5 (GT 20) to 8.0 × 10 − 5 (GT 10 and GT 15) when 10% and 15%, respectively, of beef were replaced with gari; but the control product, GT 10 and GT 15 were not significantly different (p > 0.05). However, replacing ground beef in burgers with more than 15% gari resulted in a significant increase (p b 0.05) in adhesiveness. Thus, the minimum work necessary to pull the compressing plunger on the Instron equipment away from the sample tended to reduce initially with the use of gari as an extender in beef burgers. But above 15% gari substitution for beef in the formulations, this force increased considerably. However the adhesiveness of GT 0 (control) and GT 20 were not significantly different (p > 0.05) compared to GT 10 and GT 20. Since the
cooking yields of the burgers were higher above 15% of inclusion, it is deduced that more water was retained in the burgers with more than 15% gari compared to all other levels of gari substitution, and this resulted in very soft beef burgers (Table 2).
4. Conclusions and recommendations The cooking yields of beef burgers increased with increasing usage of gari as an extender. Furthermore, using gari in beef burgers led to significant improvements in the overall consumer acceptability of the products and there were significant improvements in the texture profile as well. The flavor and odor acceptability of all the cooked products were however not statistically affected by the use of gari in the formulations. Adding gari resulted in reduced hardness, springiness, gumminess, chewiness and cohesiveness of beef burgers. Thus, gari has promise for use in meat products. It is concluded that hydrated gari could be used in beef burger formulations at the 10% level of beef substitution without compromising overall product acceptability. It is recommended that further investigations be conducted to ascertain the effect of using gari in other types of comminuted meats, including sausages. Shelf life studies and nutrient composition (protein, fat, ash and moisture) of such products should be established in future studies.
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