Volatile flavor constituents of ovine adipose tissue

Abstract

In an effort to enhance the utilization of sheep (Ovis dries) meat, this study was designed to isolate and identify compounds from ovine subcutaneous adipose tissue (Panniculus adiposus) which contribute to the characteristic flavor of the meat. Samples were taken from three Suffolk wether lambs and subsequently steam deodorized, extracted, fractionated, and analyzed. Olfactory and gas chromatographic (GC) analyses confirmed that the bulk of the flavor volatile compounds were in the neutral fraction, some in the acidic fraction, but little or none were detected in the basic fraction. Gas chromatographic-mass spectrometric (GC-MS) analysis of the neutral fraction resulted in the identification of 51 compounds: 26 aldehydes, 12 ketones, 6 lactones, 4 alcohols, and 3 cyclics. Thirty-nine of these compounds are being reported for the first time as constituents (some tentative) of ovine fat volatiles. Although no single neutral fraction compound identified could be shown to be primarily responsible for lamb/mutton flavor, 14 (10 aldehydes, 3 ketones, and 1 lactone) are suggested as important contributors to the overall flavor quality.Generally, animal meat products are well-balanced nutritionally in energy, protein, minerals, and vitamins, and their palatability makes them a desirable food source for man. Thus, the decreasing trend in the utilization of sheep meat as a foodstuff deserves immediate attention in this age of critical world food supplies (USDA, 1976). From all reports, it appears that the distinctive flavor of sheep meat (Wasserman and Talley, 1968), especially that from older animals, is somewhat less acceptable and thus responsible for its low consumption rate by U.S. consumers (Ziegler and Daly, 1968).Generally, the lipid-soluble flavor components are the most important (Sink, 1973) and many factors contribute to their expression (Sink and Caporaso, 1977). Although the lipid-soluble compounds responsible for the characteristic sheep meat (lamb or mutton) flavor are yet to be completely inventoried, current interest has focused attention on the acid fraction volatiles (Wong et al., 1975a,b).It was the purpose of this study to identify the volatile neutral fraction flavor components from ovine adipose tissue. EXPERIMENTAL PROCEDURESSampling. Following standard exsanguination and chilling (3 °C) procedures, subcutaneous fat (Panniculus adiposus) samples (300 g) were taken from three castrate-male (wether) Suffolks (Ovis aries) raised under similar management conditions and nutritional regimes.Each sample was subsequently ground through a 3-mm plate, placed under nitrogen in an impermeable container, and frozen at -29 °C. The frozen samples were then gently melted (50 °C) and filtered through several layers of cheesecloth to separate the liquid fat from the tissue residue. Olfactory evaluation indicated the liquid fat did possess the distinctive sheep meat (lamb/mutton) character.Steam Deodorization. One hundred grams of liquid fat was transferred into the 500-mL round-bottom flask

Flavor of Meat and Meat Products

“…As expected, many of the compounds identified had been previously described by Caporaso et al (1977), but Nixon et al observed that the formation of aldehydes and ketones comprising the 'muttony' shortlist of Caporaso et al depended on the cooking method. But irrespective of method, the volatiles always smelt 'sheepy' to quote Nixon et al Moreover, Dwivedi (1975) had shown that the 'muttony' volatiles also occurred in beef volatiles.…”

“…More recent studies have extended their observations. Caporaso et al (1977) rendered mutton fat (at 50°C) and judged it to have the characteristic odour even after this minimal heating. The rendered fat was then heated to simulate oven temperatures and steam extracted.…”

Quality Control of Mutton by Using Volatile Compound Fingerprinting Techniques and Chemometric Methods

“…Among the compounds mentioned in Table 1, three have been determined as the decisive characteristic flavor compounds of mutton: 4-ethyloctanoic acid (cheese, boiled mutton), 4-methylnonanoic acid (tallow, roasted, mutton), and hexanoic acid (lamb, oily) [6]. Moreover, some aliphatic aldehydes, especially some short-chain aliphatic aldehydes (C 5 -C 9 ), were also reported in sheep meat; these aldehydes are as follows: hexanal (fruity, fatty, and green), heptanal (nutty, oily, and fruity), octanal (fruity, floral, and fatty), nonanal (oily, fatty), and 2-octenal (fruity) [17]. Furthermore, 6-methyl-5-hepten-2-one, 3-methylbutanal, 2-methyl-5-(methylthio) furan, 2-undecenal, and 2,3,5,6-tetramethyl pyrazine were related to emitting meaty odors, and all of these components influence the overall mutton flavor to a certain extent.…”

S

“…Noting the importance of fat or adipose tissue in the generation of the characteristic sheepmeat flavor (Hornstein, 1963), F. Caporaso and a team at the Meats Laooratory of The Pennsylvania State University (University Park, Pennsylvania) undertook a study to determine those compounds responsible for the distinctive lamb/mutton flavor. Although the fatty acids, especially the branched chain and unsaturated C S -10 acids, have been identified as flavor constitutents (Wong, 1975), the carbonyls are the most numerous and perhaps the most important of all the various classes of compounds identified in meat flavor studies (Herz, 1970;Caporaso, 1977). Although there are both water-and fat-soluble carbonyls, Sanderson (1966) indicated those involved in meat flavor are primarily lipid-soluble.…”