Effect of enhancement and ageing on flavor and volatile compounds in various beef muscles

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MEAT SCIENCE Meat Science 79 (2008) 13–19 www.elsevier.com/locate/meatsci

Effect of enhancement and ageing on flavor and volatile compounds in various beef muscles A.J. Stetzer a, K. Cadwallader a, T.K. Singh a, F.K. Mckeith b, M.S. Brewer

a,*

a

b

Department of Food Science and Human Nutrition, University of Illinois, 202 Agricultural Bioprocess Laboratory, 1302 West Pennsylvania Avenue, Urbana, IL 61801, United States Department of Animal Science, 205 Meat Science Laboratory, 1503 South Maryland Drive, Urbana, IL 61801, United States Received 27 April 2007; received in revised form 18 July 2007; accepted 20 July 2007

Abstract To identify and quantify selected flavor-active volatile compounds and relate them to sensory characteristics, the gluteus medius (round), rectus femoris (round), vastus lateralis (round), vatsus medialis (round), teres major (chuck), infraspinatus (chuck), complexus (chuck), serratus ventralis (chuck), psoas major (loin) and longissimus dorsi (loin) were removed from heifer carcasses, enhanced, vacuum packaged, aged for 7 or 14 days, steaks were cut, vacuum packaged and frozen (48 h). Flavor-active volatiles affected by enhancement and ageing in the various muscles included nonanal, 2,3-octanedione, pentanal, 3-hydroxy-2-butanone, 2-pentyl furan, 1-octen-3-ol, butanoic acid, pentanal and hexanoic acid, compounds often associated with lipid oxidation. Enhancement decreased hexanal and hexanoic acid. Ageing decreased butanoic acid. Pentanal content varied among muscles depending on enhancement and ageing. Livery offflavor was positively correlated with pentanal, hexanal, 3-hydroxy-2-butanone and hexanoic acid. Rancid off-flavor was correlated with pentanal and with 2-pentyl furan but not with hexanal.  2007 Elsevier Ltd. All rights reserved. Keywords: Beef muscles; Volatiles; Flavor; Enhancement; Ageing

1. Introduction Consumers continue to demand high quality, consistent meat products at a reasonable price. The sensory traits that most affect consumer acceptability of beef and, therefore, repeat purchases, are tenderness and flavor (Robbins et al., 2003a, 2003b). Historically, ageing of meat products has been used to improve quality (Mottram, 1998). Beef flavor results from the combination of basic tastes (sweet, sour, bitter, salt, umami) and odor derived from volatile compounds (MacLeod, 1994). Raw, it has little aroma and only a blood-like taste. It is, however, a reservoir of aroma and flavor precursor compounds (Shahidi, 1998). Amino acids, peptides and nucleotides generated from proteins, DNA and RNA, can contribute to taste plus *

Corresponding author. Tel.: +1 217 244 2867; fax: +1 217 333 3585. E-mail address: [email protected] (M.S. Brewer).

0309-1740/$ - see front matter  2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.meatsci.2007.07.025

they can interact with other components to produce aromatic volatiles (Shahidi, 1998). Unsaturated fatty acids oxidize producing a variety of compounds some of which give characteristic species-specific odors to meat. However, other compounds may contribute noticeable off-flavors. Lipid oxidation produces a variety of aldehydes (hexanal, heptenal, pentanal, 2,4-decadienal) from phospholipids and polyunsaturated fatty acids, some of which have unpleasant odors at very low concentrations (Melton, 1990). The postmortem biochemical changes which occur during ageing have dramatic effects on tenderness (Wicklund, Stetzer, Tucker, Nicolalde, & Brewer, 2005). However, ageing also results in flavor changes (Kato & Nishimura, 1987). It increases liver-like aroma, bloody, bitter and sour off-flavors, and decreases desirable beefy, brothy, brownedcaramel and sweet flavors (Gorraiz, Beriain, Chasco, & Insausti, 2002; Spanier, Flores, McMillin, & Bidner,

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A.J. Stetzer et al. / Meat Science 79 (2008) 13–19

1997). Ageing increases carbonyls derived from lipid oxidation, some of which may contribute noticeable off-flavors. Ageing for >21 days has been shown to decrease flavor identity; ageing for 35 days increases metallic flavor (Yancey et al., 2006). Livery flavor appears to be related to heme iron and/or myoglobin levels (Calkins & Cuppett, 2006; Yancey et al., 2006). However, volatile compounds impact these flavor notes as well. Beef from bulls has a strong liver-like odor/flavor, and bloody flavor that appear to be related to higher 2-propanone and ethanal contents, while that from heifers has stronger beef flavor (Gorraiz et al., 2002). Carcass maturity can affect iron content increasing metallic, sour, rancid, bloody, salty and bitter flavor notes (Calkins, 2006). The enhancement of poultry and pork has been used to ensure that a consistently tender product reaches the consumer (Brewer, Jensen, Prestat, Zhu, & McKeith, 2002). This same technology has recently been applied to beef in order to ensure consumers receive consistent, quality products (Vote et al., 2000). The components used in enhancement solutions for meat products could alter the volatile flavor compounds found in different muscles. Sodium salts of tripolyphosphate, hexametaphosphate and/or pyrophosphate, often used during enhancement, increase meaty flavor and decrease stale and rancid flavor/aroma and hexanal during storage, however they can produce a soapy aftertaste (Vote et al., 2000). By gaining a better understanding of which muscles would benefit most from enhancement and ageing, the beef industry will benefit economically. The objectives of this project were to identify and quantify the volatile compounds in the gluteus medius (round), rectus femoris (round), vastus lateralis (round), vatsus medialis (round), teres major (chuck), infraspinatus (chuck), complexus (chuck), serratus ventralis (chuck), psoas major (loin) and longissimus dorsi (loin) enhanced prior to ageing and relate them to sensory characteristics. 2. Materials and methods 2.1. Sample manufacture Twenty USDA Select heifer carcasses from cattle with commercial genetic backgrounds were obtained from a commercial supplier. Slaughter weights ranged from 270 to 320 kg. The gluteus medius (round), rectus femoris (round), vastus lateralis (round), vatsus medialis (round), teres major (chuck), infraspinatus (chuck), complexus (chuck), serratus ventralis (chuck), psoas major (loin) and longissimus dorsi (loin) were removed 48 h after slaughter at the University of Illinois Meat Science Laboratory. Carcass identity was maintained throughout the study. The muscles from one side of each carcass were used as the non-enhanced control. The muscles from the remaining side were enhanced to a target of 108% of original weight to target final concentrations of 0.4% phosphate (Curavis

250, Innophos, Cranbury, NJ, USA) and 0.3% salt for comparison with non-enhanced samples. Enhancement solution, pH 7.2, was injected at 0 C, 150 kPa and 52 strokes/min through injection needles spaced 2.5 cm apart using a multi-injector system (Model N50, Wolf-tec Inc., Kingston, NY). Each muscle was divided into two sections (1/ageing period), individually vacuum-packaged (Multivac C500, Koch Supplies, Inc., Kansas City, MO), then aged at 4 C for 7 or 14 days. Sections were removed from vacuum bags, sliced into 2.5 cm steaks, vacuum-packaged, and held at 4 C until evaluation (24–48 h). 2.2. Flavor evaluation The 10-member sensory panel consisted of graduate students and staff at the University of Illinois experienced in meat product evaluation by virtue of having participated in a minimum of 3 beef sensory panels over the last year. The panel was trained over a 2 week period to evaluate tenderness, juiciness, saltiness, beef flavor and oily mouth-feel (Prestat, Jensen, McKeith, & Brewer, 2002; Moskowitz, 1988) using reference standards shown in Table 1. Sample attributes were evaluated on a semi-structured 15 cm line scale where 0 = none and 15 = intense. Standards were provided during both training and testing sessions. Flavor evaluation was conducted under controlled (dim) light conditions with one panelist per table. Samples were presented within 2 min of cooking. The flavor panel evaluated two sets of five samples per session allowing 3 min between samples and 1 h between sets. Four sessions were conducted daily, two in the morning, two in the afternoon. Steaks were cooked to 70 C on Farberware Open Hearth grills (Model 455N, Walter Kidde, Bronx, NY), turned approximately half way through the cooking period. Internal temperature was monitored using copper constantin fine-wire thermocouples (Model 5SC-TT-T30-36, Omega Engineering, Inc., Stamford, CT) connected to a 12-channel scanning thermocouple thermometer (Model 92000-00, Cole-Parmer Instrument Company, Vernon Hills, IL). Cooked samples were trimmed of edges then cut into serving pieces (1.3 · 1.3 · 2.5 cm), coded with three-digit random numbers and presented to panelists on white paper plates with apple juice and distilled water (23 C) to cleanse the palate. The sensory panel evaluated two sets of five samples per session. Both enhanced and non-enhanced samples were evaluated in random order across a session. Sensory data are reported in centimeters from the left end of the line scale. 2.3. Composition The pH of steaks was determined using a PH-STAR probe (SFK Technologies, Cedar Rapids, IA). Moisture and fat content were determined following each ageing period (AOAC, 1990). Samples (10 g) were trimmed of fat and

A.J. Stetzer et al. / Meat Science 79 (2008) 13–19

15

Table 1 Standards used for flavor profiling of enhanced, aged beef muscles Characteristic

Standard

Scale value1

Saltiness Beef flavor Livery flavor Rancid flavor Oiliness

0.25% NaCl solution 0.25% Natural roast beef flavor, Innova, Griffiths Lab., Oak Brook, IL + 0.125% NaCl solution Fresh calf liver, cooked to 70 C on open hearth grills Melted, Land O’Lakes, unsalted, sweet cream butter (Land O’Lakes, Inc., Arden Hills, MN), stored at 22 C for 4 week Old Wisconsin Premium Bratwurst, fully cooked, 33% fat, Old WI Food Prod. Co., Inc., Sheboygan, WI. Steamed to 65C internal All-beef Ball Park Franks [65 C], Ball Park Brands, Southfield, MI Bob Evans Ham steaks [10% water added], 96% fat free, Bob Evans Farms, Columbus, OH

8 10 13 10 10

Tenderness Juiciness 1

13 8

Scale: 0 = none and 15 = intense.

connective tissue, homogenized (KitchenAid food processor, St. Joseph, MI), and oven dried to a constant weight (48 h). Moisture content was determined by weight difference. Fat content was determined by extraction with an azeotropic mixture of warm chloroform and methanol (4:1; Novakofski, Park, Betchel, & McKeith, 1989). 2.4. Analysis of volatile compounds Cooked steaks were cut into six 1.5 cm cubes, frozen by immersion in liquid nitrogen for 5 min and ground to a fine powder in a blender jar. Powder was immediately transferred to triplicate 22-mL headspace vials (1.0 g per vial), sealed with a Teflon-lined septum and stored at 70 C until analysis (up to 48 h). Selected volatile constituents were analyzed by solidphase microextraction–gas chromatography–mass spectrometry (SPME–GC–MS) using an HP5890 Series II GC/HP5970B mass selective detector (Agilent Technologies, Inc., Palo Alto, CA) equipped with an MPS2 multipurpose autosampler (Gerstel, Germany). Prior to analysis the sample vial was spiked with 1 lL of an internal solution (containing 0.50 mg/mL of 2-methyl-3-heptanone in methanol). The vial was equilibrated at 60 C for 20 min with agitation (300 rpm, 5 s on, 2 s off), then an SPME fiber Carboxen/polydimethylsiloxane fiber; Supelco, Bellefonte, PA was exposed to the vial headspace for an additional 20 min. Immediately after sampling the fiber was desorbed by splitless injection (injector temperature 260 C; splitless time 1 min; vent flow 50 mL/min) into a DB-FFAP (30 m · 0.25 mm i.d. · 0.25 lm film; J&W Scientific, Folsom, CA) column. Helium was the carrier gas at 1 mL/min. The GC oven temperature was programmed from 35 to 225 C at a rate of 4 C/min with initial and final hold times of 5 and 30 min, respectively. MSD conditions were as follows: capillary direct interface temperature, 250 C; ionization energy, 70 eV; mass range, 35– 300 amu; electron multiplier voltage (Autotune + 200 V); scan rate, 2.2 scans/s. Compounds were identified by comparison of their mass spectra and retention indices (van den Dool & Kratz, 1963) to those of authentic standards. Quantitative analysis was performed using internal standard methodology as described by Zhou, Wintersteen, and Cadwallader (2002).

2.5. Statistical analyses Data were analyzed as a 10 (muscles) by 2 (enhancement treatments) by 2 (ageing periods) factorial design treating carcass as a repeated measure using PROC MIXED (SAS, 2002). The model included muscle, ageing time, enhancement and appropriate interactions. Carcass was treated as a repeated measure to reduce the impact of carcass-to-carcass variation and because all treatment combinations (muscle/enhancement/ageing time) were contained within each carcass. For flavor evaluations, the means of the panelist’s scores were calculated for each carcass/muscle/enhancement/ageing combination. Effects were considered significant at P < 0.05. Least squares means were separated using probability of difference. Pearson correlation coefficients were calculated among sensory characteristics and volatiles. 3. Results and discussion 3.1. Characteristics of various muscles When averaged over enhancement and ageing time, clear differences emerged in fat content among the various muscles (Table 2). The infraspinatus and the serratus ventralis, both derived from the chuck, contained more than 8% fat while gluteus medius, rectus femoris, and vastus lateralis, all derived from the round, contained less than 5% fat. These fat content differences may be the source of flavor and volatile differences. The complexus (chuck) had the highest beef flavor intensity score, and the rectus femoris (chuck) had the lowest, however the range was narrow (6.9–7.7 on a 15-point scale). These flavor differences mirror the trends in fat content among the muscles. The gluteus medius (round) had the highest livery off-flavor score and the longissimus dorsi (loin) had the lowest, however all scores were very low and the range was small (0.5–0.9). Calkins and Cuppett (2006) reported that livery flavor increases and beef flavor decreases in some muscles as iron content increases. Muscles often exhibiting liver-like flavor, such as the psoas major (loin) and gluteus medius (round) generally have higher levels of heme iron and/or myoglobin (Yancey et al., 2006).

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Table 2 Characteristics of various enhanced, aged beef muscles Characteristic

Gluteus medius (round)

Rectus femoris (round)

Vastus lateralis (round)

Vastus medialis (round)

Serratus ventralis (chuck)

Infra spinatus (chuck)

Teres major (chuck)

Complexus (chuck)

Psoas major (loin)

Longissiumus dorsi (loin)

SEM

Moisture, % Fat, % 3-Hydroxy-2butanone, lg/g Beef flavor1 Livery offflavor1

73.26ab 4.57c 0.30a

74.23a 4.07c 0.17ab

74.23a 3.46d 0.18ab

Na Na 0.09b

72.01bc 8.50a 0.28a

71.27c 8.18a 0.16ab

Na Na 0.19ab

73.74ab 5.96b 0.17ab

72.27bc 6.11b 0.20ab

72.68abc 4.44c 0.12b

0.39 0.29 0.04

6.89d 0.77ab

6.97cd 0.77ab

7.53ab 0.55ab

7.65a 0.53b

7.43ab 0.69ab

7.23bcd 0.52b

0.12 0.09

7.23bcd 0.90a

7.38abc 0.77ab

7.46ab 0.63ab

7.29abc 0.69ab

abcd 1

Means with like superscripts do not differ (P < 0.05). Scale: 0 = none, 15 = intense.

3.2. Effect of enhancement Enhancement (averaged over muscle and ageing time) increased moisture content by about 1.5% (Table 3). It decreased pentanal and 3-hydroxy-2-butanone content by nearly 50%. The former contributes a pungent aroma and is often correlated with lipid oxidation (TBARS; Ahn et al., 1998). It decreased rancid and livery off-flavors, both by about one third, although the latter two were less than one before and after enhancement. It is possible that enhancement decreased 2,3-octanedione and nonanal content via dilution, however enhancement to 8% over initial weight seems insufficient to account for a 50% reduction in these compounds. The decrease in lipid oxidation products was not unexpected as the polyphosphates contained in the enhancement solution can chelate iron decreasing its prooxidative impact. Enhancement increased beef flavor intensity by about 1 unit on the 15-point sensory scale (7%); this was not unexpected given that the enhancement solution contained salt which serves as a flavor enhancer. 3.3. Effect of enhancement on various muscles The hexanal content of the non-enhanced complexus (chuck) was higher than that in the muscles from the round (gluteus medius, rectus femoris, vastus lateralis, vastus medialis; Table 4). After enhancement, the hexanal content of Table 3 Effects of enhancement on characteristics of aged beef Characteristic

Moisture, % Fat, % Pentanal 3-Hydroxy-2-butanone, lg/g Beef flavor1 Rancidity1 Livery off-flavor1 ab 1

Enhancement

SEM

Control

Enhanced

72.19b 5.97a 0.19a 0.25a 6.79b 0.43a 0.83a

73.73a 5.35b 0.10b 0.13b 7.84a 0.27b 0.53b

Means with like superscripts do not differ (P < 0.05). Scale: 0 = none, 15 = intense.

0.20 0.15 0.01 0.02 0.04 0.02 0.03

psoas major (chuck) was higher than that of any of the other muscles. Hexanal contributes a ‘‘fatty’’ sometimes ‘‘grassy’’ aroma (Elmore, Mottram, & Enser, 1999). This may be, in part, a function of the fat content of the complexus compared to muscles from the round. Nonenhanced muscles from the chuck (complexus, teres major, serratus ventralis, infraspinatus) contained more 1-octen-3ol than other non-enhanced muscles (Table 3). This compound (1-octen-3-ol ) can contribute a mushroomy, mossy, nutty odor which may be characteristic of the muscles from the chuck whether or not these muscles are enhanced. No significant differences existed after enhancement. The non-enhanced serratus ventralis and infraspinatus, both derived from the chuck, had the highest scores for oily mouthfeel, however after enhancement, these same muscles as well as the complexus, also from the chuck, all had significantly higher scores than the other muscles evaluated. Prior to enhancement, no differences in saltiness existed due to muscle. This was expected. After enhancement, the complexus (chuck) was more salty than the rectus femoris and vastus lateralis, both from the round, with all other muscles falling in between. The reason why some muscles became more salty when enhanced while others did not, given they did not differ initially, is unclear. 3.4. Effects of ageing and enhancement on various muscles Significant enhancement by ageing · muscle interactions existed for 2-pentyl furan, 2,3-octanedione, nonanal, butanoic acid and hexanoic acid (Table 5). 2-Pentyl furan has a green, earthy, beany flavor note. No difference existed in 2pentyl furan content among non-enhanced muscles (p < 0.05). Enhancement nearly doubled the content of this compound in the psoas major (loin) between 7 and 14 days. Neither affected 2-pentyl furan content in other muscles. The 2,3-octanedione and nonanal contents of the nonenhanced complexus (chuck) were significantly higher than those of the enhanced complexus. 2,3-Octanedione has a warmed over, oxidized fat flavor. Nonanal has a soapy, tallowy flavor. Nonanal content did not differ among other enhanced muscles after 7 days of ageing however, after

0.69e 0.01ef 2.57ghij 7.28ab 1.44bcde 0.03cdef 4.74ab 7.20ab 0.83de 0.02def 4.94a 7.56ab 0.92de 0.02cdef 3.55def 7.87ab

0.62e 0.02cdef 4.54abc 8.49a

3.5. Correlations between volatiles and sensory attributes

1

abcdefghij

Means with like superscripts do not differ (P < 0.05). Scale: 0 = none, 15 = intense.

0.77de 0.02cdef 3.61def 7.89ab 0.71e 0.01def 2.74fgh 6.90b 1.02cde 0.03cdef 2.80fghi 6.38b 0.86de 0.02cdef 2.56ghij 7.25ab Enhanced Hexanal, lg/g 1-Octen-3-ol, lg/g Oily mouthfeel Saltiness

17

14 days, it was significantly higher in the enhanced psoas major (loin) compared with all other muscles. Butanoic acid increased with ageing time in non-enhanced complexus (chuck) and in enhanced rectus femoris (round) and psoas major (loin).Butanoic acid has a rancid odor. No difference existed among non-enhanced muscles, regardless of ageing time, in hexanoic acid content. Enhanced psoas major (loin) had a higher content of hexanoic acid than did other enhanced muscles after 7 days. The concentration of this compound nearly doubled after 14 days of ageing. Hexanoic acid has a ‘‘sweaty’’ odor (Spanier, Vercellotti, & James, 1992). Ageing up to 14 days has been shown to increase fatty flavor and positive flavor notes such as ‘‘beefy’’, ‘‘brothy’’, ‘‘sweet’’ and ‘‘browned caramel’’ as well as some negative attributes like ‘‘painty’’, ‘‘cardboard’’, ‘‘bitter’’ and ‘‘sour’’ (Bruce, Beilken, & Leppard, 2005; Gorraiz et al., 2002; Qian & Reineccius, 2003; Spanier et al., 1997).

2.57a 0.01f 2.98fgh 7.15ab

2.03abcde 0.04bcde 1.96j 3.03c 1.18bcde 0.02def 2.98fgh 3.34c 2.46abc 0.04bcd 4.16bcd 3.61c 2.30abcd 0.05bc 3.80cde 3.61c 1.21bcde 0.03cdef 2.02ij 3.08c 0.93 de 0.02cdef 2.30hij 2.98c Control Hexanal, lg/g 1-Octen-3-ol, lg/g Oily mouthfeel1 Saltiness1

1.25bcde 0.02cdef 2.32hij 3.14c

1.42bcde 0.04bcdef 2.55ghij 3.11c

2.13abcde 0.07ab 2.82fghi 3.96c

3.42a 0.10a 3.27efg 3.12c

Infra spinatus (chuck) Vastus lateralis (round) Rectus femoris (round) Gluteus medius (round)

Muscle

Table 4 Effects of enhancement on characteristics of aged beef muscles

Vastus medialis (round)

Teres major (chuck)

Complexus (chuck)

Serratus ventralis (chuck)

Psoas major (loin)

Longissiumus dorsi (loin)

A.J. Stetzer et al. / Meat Science 79 (2008) 13–19

Beef flavor was negatively correlated with pentanal (Table 6). This inverse relationship may indicate a loss of beef flavor as by-products of lipid oxidation accumulated. Higher levels of this volatile may have overpowered this sensory attribute as it has a pungent odor. Liver off-flavor was positively correlated with pentanal, hexanal, 3hydroxy-2-butanone and hexanoic acid, compounds which can contribute pungent, grassy or fatty, buttery, and sweaty odors, respectively (MacLeod, 1994; MacLeod & Ames, 1986; Mottram, 1998; Rowe, 2002; Shahidi, 1998; Spanier & Miller, 1993, chap. 6; Spanier et al., 1992). Aldehydes often have tallowy, meaty odors (Rowe, 2002). Rancid off-flavor was correlated with pentanal and with 2pentyl furan (metallic, green, earthy, beany) but not with hexanal (grassy, fatty). Beef flavor was highly correlated with saltiness (Table 6) and negatively correlated with rancid and liver off-flavors. As previously mentioned, presence of lipid oxidation products may have masked beef flavor. Yancey et al. (2006) and Hodgen et al. (2006) have correlated livery flavor with 16-, 17-, 18- and 20-carbon chain fatty acids (2-decenal, 2undecenal, propanoic acid; vaccenic acid, cis-11,14-eicosadienoic acid, 5,8,11,14,17-eicosapentaenoic acid). Oily mouth-feel was correlated with beef flavor and with saltiness. 3.6. Correlations between volatiles A number of the break down products of lipid oxidation were correlated with each other. Nonanal was highly correlated with 2,3-octanedione (R2 = 0.75) and 1-octen-3-ol (R2 = 0.79; data not shown). Pentanal was correlated with hexanal (R2 = 0.67), 2-pentyl furan (R2 = 0.44), 3-hydroxy2-butanone (R2 = 0.58), 2,3-octanedione (R2 = 0.48), nonanal (R2 = 0.21), 1-octen-3-ol (R2 = 0.23), butanoic acid (R2 = 0.39) and hexanoic acid (R2 = 0.60). Hexanal was

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A.J. Stetzer et al. / Meat Science 79 (2008) 13–19

Table 5 Effects of enhancement and ageing on volatiles (lg/g) in various beef muscles Aged 7 days 2-Pentyl furan

2,3-Octane dione

Nonanal

Butanoic acid

Hexanoic acid

2-Pentyl furan

2,3-Octane dione

Nonanal

Butanoic acid

Hexanoic acid

0.044b 0.048b 0.057b 0.069b 0.098b 0.108b 0.131a 0.081b 0.040b 0.060b

0.044defg 0.050defg 0.057defg 0.069bcdefg 0.098bcde 0.108abcde 0.131ab 0.081bcdefg 0.040efg 0.061cdefg

0.024def 0.015f 0.023ef 0.018ef 0.025def 0.026def 0.046cde 0.033def 0.032def 0.022ef

0.016c 0.029c 0.022c 0.017c 0.033c 0.025c 0.042bc 0.032c 0.034bc 0.027c

0.008c 0.008c 0.018c 0.020c 0.022c 0.023c 0.036c 0.020c 0.007c 0.020c

0.030b 0.033b 0.060b 0.081b 0.089b 0.119b 0.173a 0.097b 0.026b 0.084b

0.031efg 0.033efg 0.060defg 0.081bcdefg 0.089bcdef 0.119abcd 0.173a 0.097bcde 0.026g 0.084bcdefg

0.024def 0.017f 0.029def 0.032def 0.023ef 0.034def 0.052cd 0.040cdef 0.031def 0.033def

0.021c 0.021c 0.026c 0.023c 0.044bc 0.032c 0.035bc 0.031c 0.021c 0.032c

0.015c 0.017c 0.010c 0.007c 0.012c 0.014c 0.013c 0.009c 0.024c 0.083b 0.013c 0.015c

0.060b 0.051b 0.038b 0.029b 0.035b 0.040b 0.046b 0.040b 0.033b 0.085b 0.033b 0.060b

0.061cdefg 0.051defg 0.038efg 0.029fg 0.035efg 0.040efg 0.046defg 0.040efg 0.033efg 0.085bcdefg 0.033efg 0.061cdefg

0.022ef 0.023ef 0.017ef 0.013f 0.010f 0.016f 0.016f 0.022ef 0.026def 0.065c 0.020ef 0.022ef

0.027c 0.024c 0.020c 0.017c 0.015c 0.026c 0.021c 0.014c 0.027c 0.076b 0.019c 0.027c

0.013c 0.011c 0.007c 0.003c 0.014c 0.008c 0.008c 0.009c 0.146a 0.004c 0.013c 0.011c

0.058b 0.045b 0.025b 0.025b 0.050b 0.028b 0.029b 0.025b 0.125b 0.025b 0.058b 0.045b

0.058defg 0.045defg 0.025g 0.025g 0.050defg 0.028fg 0.029fg 0.025g 0.125abc 0.025g 0.058defg 0.045defg

0.019ef 0.191a 0.013f 0.011f 0.016f 0.019ef 0.025def 0.035def 0.102b 0.014f 0.019ef 0.191a

0.019c 0.024c 0.023c 0.014c 0.023c 0.017c 0.024c 0.033c 0.123a 0.016c 0.019c 0.024c

0.001

0.011

0.050

0.008

0.007

0.001

0.011

0.050

0.008

0.007

Control (non-enhanced) Gluteus medius (R) 0.010c Rectus femoris (R) 0.017c Vastus lateralis (R) 0.015c Vastus medialis (R) 0.019c Infraspinatus (C) 0.027c Teres major (C) 0.023c Complexus (C) 0.036c Serratus ventralis (C) 0.019c Psoas major (L) 0.021c Longissiumus dorsi 0.015c (L) Enhanced Gluteus medius (R) Rectus femoris (R) Vastus lateralis (R) Vastus medialis (R) Infraspinatus (C) Teres major (C) Complexus (C) Serratus ventralis (C) Psoas major (L) Gluteus medius (R) Rectus femoris (R) Longissiumus dorsi (L) Standard Error of the Mean

Aged 14 days

R = round, C = chuck , L = loin. Means within a column for a compound with like superscripts do not differ (P < 0.05).

abcdefg

Table 6 Correlations between flavor-active volatiles and sensory attributes in enhanced, aged beef Beef flavor Pentanal Hexanal 2-Pentyl furan 3-Hydroxy-2-butanone Hexanoic acid Beef flavor Rancid off-flavor Saltiness Liver off-flavor

0.20

Rancid offflavor

Oily mouth feel

Saltiness

0.20

Liver off-flavor

P-value

0.31 0.23

<0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001

0.26 0.34 0.22 – 0.27 0.74 0.30

0.30 – 0.45 0.25

0.22 – 0.28

–

Correlation coefficients (R2) presented are significant at P < 0.05.

correlated with 2,3-octanedione (R2 = 0.67), nonanal (R2 = 0.60), 1-octen-3-ol (R2 = 0.60), butanoic acid (R2 = 0.45) and hexanoic acid (R2 = 0.67). These correlations were not unexpected as they are all reflective of lipid oxidation of the unsaturated fatty acids found in beef. 4. Conclusions Enhancement increased positive sensory attributes (beef flavor, saltiness, pH and moisture content) and decreased

negative attributes (off-flavors). The salt in the enhancement solution would be expected to impact flavor by increasing saltiness and beef flavor which in turn may have masked low levels of off-flavors originally present or after ageing. Flavor-active volatiles affected by enhancement and ageing in the various muscles included primarily those indicative of lipid oxidation (nonanal, 2,3-octanedione, pentanal, 3-hydroxy-2-butanone, 2-pentyl furan, 1-octen3-ol, butanioc acid, pentanal and hexanoic acid), however differences were small. Enhancement decreased hexanal

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and hexanoic acid. This was likely due to some suppression of lipid oxidation. It also reduced rancidy. Ageing decreased butanoic acid. Some variation in responses may be explained by the original variation in the 10 muscles. Enhancement increased quality characteristics of muscles however some benefited more than others. Ageing had smaller effects. The complexus appeared to benefit the most from enhancement followed by the teres major and the serratus ventralis. Acknowledgements This material is based upon work supported by the National Cattlemen’s Beef Association Beef Checkoff. The authors would also like to thank Mr. Charles Stites, University of Illinois Meat Science Laboratory, for sample manufacture, and Mr. John Jarrell, University of Illinois, Department of Food Science and Human Nutrition, for gas chromatographic analysis of samples. References Ahn, D. U., Olson, D. G., Lee, J. I., Jo, C., Wu, C., & Chen, S. (1998). Packaging and irradiation effects on lipid oxidation and volatiles in pork patties. Journal of Food Science, 63(1), 15–19. AOAC (1990). Official methods of analysis (15th ed.). Washington, DC: Association of Official Analytical Chemists. Brewer, M. S., Jensen, J., Prestat, C., Zhu, L. G., & McKeith, F. K. (2002). Visual acceptability and consumer purchase intent of enhanced pork loin roasts. Journal of Muscle Foods, 13(1), 53–68. Bruce, H. L., Beilken, S. L., & Leppard, P. (2005). Textural descriptions of cooked steaks from bovine M. longissimus thoracis et lumborum from different production and ageing regimes. Journal of Food Science, 70, S309–S316. Calkins, C. R. (2006). Mitigation of flavor in fed and non fed cow beef. Final report to the National Cattlemens Beef Association. Centennial, CO. Calkins, C. R., & Cuppett, S. (2006). Volatile compounds in beef and their contribution to off-flavors. Final report to the National Cattlemens Beef Association. Centennial, CO. Elmore, J. S., Mottram, D. S., & Enser, M. (1999). Effect of the polyunsaturated fatty acid composition of beef muscle on the profile of aroma volatiles. Journal of Agricultural Food Chemistry, 47(4), 1619–1625. Gorraiz, C., Beriain, M. J., Chasco, J., & Insausti, K. (2002). Effect of ageing time on volatile compounds, odor, and flavor of cooked beef from Pirenaica and Friesian bulls and heifers. Journal of Food Science, 67, 916–922. Hodgen, J. M., Calkins, C. R., & Cuppett, S. L. (2006). Identification of off-flavored compounds in beef. In Proceedings, reciprocal meat conference (pp. 1). Urbana, IL: American Meat Science Association. Kato, H., & Nishimura, T. (1987). Taste components and conditioning of beef, pork and chicken. In Y. Kawarmura & M. R. Kare (Eds.), Umami: One of the basic tastes. New York: Marcel Dekker. MacLeod, G. (1994). The flavor of beef. In F. Shahidi (Ed.), Flavor of meat and meat products (pp. 4–37). London: Blackie Academic and Professional.

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