http://www2.kobe-u.ac.jp/~toyoda/beef/BEEF/Ref/beef%20production_fat.pdf

Innovations in beef production systems that enhance the nutritional and health value of beef lipids and their relationship with meat quality.

A fresh look at meat flavor

Grass feeding has been reported to affect several meat quality characteristics, in particular colour and flavour. In this paper we have reviewed some differences in meat colour and flavour between ruminants fed concentrates and animals allowed to graze pasture. The possible factors influ- encing the differences have been also examined. We have examined a total of 35 experiments which report the effect of pasture vs concentrate finishing systems on beef meat colour. Meat from cattle raised on pasture is reported to be darker than meat from animals raised on concentrates if measured by objec- tive (P < 0.001) as well as subjective ( P < 0.05) methods. Several factors, not a specific one are responsible for this difference, variations in ultimate-pH and in intramuscular fat content between ani- mals finished at pasture and those finished on concentrates, seem to play a major role. Diet also affects meat flavour in both sheep and cattle but the components involved seem to be different. In sheep pastoral flavour is mostly determined by the branched-chain fatty acids and 3-methylindole (ska- tole). An important role seems to be played also by some products of oxidation of linolenic acid and its derivates. In cattle the role of skatole seems to be less important than sheep because of the lack of the branched-chain fatty acids. The pastoral flavour seems to be mostly determined by products of oxidation of linolenic acid and its derivates which derives substantially from grass. grass feeding / meat colour / meat flavour / ruminants

https://hal.archives-ouvertes.fr/hal-00889868/document

Effects of grass feeding systems on ruminant meat colour and flavour. A review

Meat quality describes the attractiveness of meat to consumers. The present paper focuses on two major aspects of meat quality, tenderness and flavour. Both aspects of quality can be influenced by nutrition, principally through its effects on the amount and type of fat in meat. In several countries, high levels of intramuscular fat (marbling fat), i.e. above 30 g/kg muscle weight in longissimus, are deemed necessary for optimum tenderness, although poor relationships between fat content and tenderness have generally been found in European studies, where fat levels are often very low, e.g. below 10 g/kg in UK pigs. Muscle lipid may be a marker for red oxidative (type 1) muscle fibres which are found at higher concentrations in tender muscles and carcasses. Nutritional treatment can be used to manipulate the fatty acid content of muscle to improve nutritional balance, i.e. increase the polyunsaturated (PUFA): saturated fatty acid value and reduce the n-6:n-3 PUFA value. Increasing PUFA levels may also change flavour because of their greater susceptibility to oxidative breakdown and the generation of abnormal volatile compounds during cooking. This situation particularly applies to the n-3 PUFA which are the most unsaturated meat lipids. In pigs, a concentration of 3 mg alpha-linolenic acid (18:3)/100 mg in muscle and fat tissue fatty acids can easily be achieved by including whole linseed in the diet. This level has led to abnormal odours and flavours in some studies, but not in others. In cattle and sheep, feeding whole linseed raised 18:3 concentrations in muscle fatty acids from about 0.7 mg/100 mg to > 1 mg/100 mg. As with pigs, this diet also increased levels of long-chain n-3 PUFA formed from 18:3, including eicosapentaenoic acid (20:5). Although this increase led to greater oxidative breakdown of lipids during storage and the generation of large quantities of lipid-derived volatile compounds during cooking, there were no deleterious effects on odour or flavour. When 18:3 levels are raised in lamb and beef because of grass feeding, the intensity of the flavours increases in comparison with grain-fed animals which consume and deposit relatively more linoleic acid (18:2). In ruminants, very high levels of 18:2 produced by feeding protected oil supplements cause the cooked beef to be described as oily, bland or pork-like.

/pdf/manipulating-meat-quality-and-composition-398ut9gdpg.pdf

Manipulating meat quality and composition.

Effect of a grass-based and a concentrate feeding system on meat quality characteristics and fatty acid composition of longissimus muscle in different cattle breeds

Hereford yearling steers (N= 144) were alloted to one of three pasture systems: tall fescue, smooth bromegrass-red clover or orchardgrass-red clover. After the grazing period, steers were finished in drylot and then serially slaughtered at 0, 56, 84 and 112 days. Carcass quality grades and yield grade numbers increased when steers were fed grain up to 112 days. Tenderness of loin steaks increased up to 84 days, after which no improvements were observed. Sensory panel scores for grassy flavor of steaks and ground beef decreased up to 112 days. Fifty-three compounds were identified in the volatiles of melted subcutaneous fat by direct sampling-gas chromatography/mass spectro-metry. The major differences between volatiles from fat of forage-fed compared to grain-fed steers were the higher concentrations of 2,3-octanedione and various diterpenoids present in the samples of the forage-fed animals.

Flavor Constituents of Beef as Influenced by Forage‐ and Grain‐Feeding

A2 x 3 factorial experiment was conducted to evaluate chemical treatments (three) and storage methods (two) on maintaining qualiy of large round bales of fescue hay. Bale treatments were with anhydrous ammonia, sodium diacetate and a control. Bales were stored either inside or outside for 120 days prior to feeding. Dry matter losses were significant in all the bales, with the greatest loss in the outer layer of the bales stored outside. Bales treated with anhydrous ammonia had the least dry matter loss. In vitro dry matter disappearance was significantly higher for the anhydrous ammonia treated hay than for other treatments. Microbial damage was more severe in the bales stored outside than in those stored inside with the greatest amount of mold occurring in the bales treated with sodium diacetate. In a feeding trial cows showed no significant difference in average daily gain when fed hay from the various treatments..

J. E. Williams

Papers

Flavor Constituents of Beef as Influenced by Forage‐ and Grain‐Feeding

Quality Evaluation of Large Round Bales Treated with Sodium Diacetate or Anhydrous Ammonia