牛至精油对平凉红牛半腱肌肉品质、脂肪酸及挥发性风味物质的影响

Effects of Oregano Essential Oil on Meat Quality,Fatty Acids and Volatile Flavor Compounds in Semitendinosus of Pingliang Red Cattle

本试验旨在研究牛至精油对平凉红牛半腱肌肉品质、脂肪酸和挥发性风味物质的影响。选取27头初始体重为(270.47±16.26)kg的平凉红牛阉牛,随机分为3组(每组9头),在饲喂基础饲粮的同时分别补饲0(Con组)、130(L组)和260 mg/d(H组)的牛至精油。饲喂404 d后屠宰,其中预试期14 d,正试期390 d,每30 d为1个阶段。结果显示:1)H组半腱肌的亮度值显著低于Con组(P<0.05);L组半腱肌的pH和熟肉率显著高于Con组(P<0.05),而失水率和剪切力显著低于Con组(P<0.05)。2)L组和H组半腱肌中饱和脂肪酸的含量显著低于Con组(P<0.05),而不饱和脂肪酸的含量显著高于Con组(P<0.05);L组和H组半腱肌中肉豆蔻酸和十七烷酸的含量显著低于Con组(P<0.05),而油酸的含量显著高于Con组(P<0.05);L组半腱肌中二十三烷酸的含量显著低于Con组(P<0.05),而α-亚麻酸和共轭亚油酸的含量显著高于Con组(P<0.05)。3)在平凉红牛半腱肌中共检测到50种挥发性风味物质,其中醛类11种,醇类4种,酮类3种,酯类5种,酸类2种,烃类22种,其他类3种。L组半腱肌中庚醛和戊醛的相对含量显著高于Con组(P<0.05),1-辛烯-3-醇的相对含量显著高于Con组和H组(P<0.05),2-戊基呋喃的相对含量显著高于H组(P<0.05),乙酸乙酯仅在L组和H组中检测到。根据相对气味活度值(ROAV)判断得出,壬醛为平凉红牛肉的关键风味物质(ROAV=100),在3个组中分别找到了9、10、7个关键风味物质,其中乙酸乙酯为L组的特有关键风味物质。综上所述,牛至精油降低了平凉红牛半腱肌的嫩度,提高了半腱肌的多汁性和适口性,并可提供理想的脂肪酸组成和含量以及丰富的挥发性风味物质,且当补饲量为130 mg/d时,牛肉的品质最佳。

This study investigated the oregano essential oil(OEO)on meat quality,fatty acids and volatile flavor compounds in the semitendinosus of Pingliang red cattle.Twenty-seven castrated Pingliang red cattle with an initial body weight of(270.47±16.26)kg were randomly divided into 3 groups with 9 cattle per group,they were fed a basal diet and extra provided 0(Con group),130 mg/d(L group)and 260 mg/d(H group)OEO,respectively.The experimental period was 404 d prior to harvest during which time 14 d for pre-experiment period and 390 d for formal experiment period,and each 30 days was a stage.The results showed as follows:1)the lightness value of semitendinosus of the H group was significantly decreased compared with the Con group(P<0.05);the pH and cooked meat rate of semitendinosus of the L group were significantly increased(P<0.05),while the water lose rate and shear force were significantly decreased compared with the Con group(P<0.05).2)Saturated fatty acid content in semitendinosus of the L and H groups was significantly lower than that of the Con group(P<0.05),while the unsaturated fatty acid content was significantly higher than that of the Con group(P<0.05);the contents of myristic and margaric acids in semitendinosus of the L and H groups were significantly lower than those of the Con group(P<0.05),while the oleic acid content was significantly higher than that of the Con group(P<0.05);tricosanoic acid content in semitendinosus of the L group was significantly lower than that of the Con group(P<0.05),while the contents ofɑ-linolenic acid and conjugate linoleic acid were significantly lower than those of the Con group(P<0.05).3)A total of 50 volatile flavor compounds were detected in semitendinosus of Pingliang red cattle,including 11 aldehydes,4 alcohols,3 ketones,5 esters,2 acids,22 hydrocarbons and 3 others.The relative contents of heptanal and pentanal in semitendinosus of the L group were significantly higher than those of the Con group(P<0.05);the oct-1-en-3-ol relative content in semitendinosus of the L group was significantly higher than that in the Con and H groups(P<0.05),and the 2-pentyl furan relative content was significantly higher than that in the H group(P<0.05);ethyl acetate was detected only in L and H groups.Nonanal was eventually determined the key volatile flavor compounds of Pingliang red cattle by relative odor activity value(ROAV),and 9,10 and 7 key flavor compounds were found in the three groups,respectively,among which ethyl acetate was the unique key flavor compound of L group.In conclusion,OEO decreases meat tenderness,improves the juiciness and palatability,provides ideal fatty acid composition and contents as well as rich volatile flavor compounds of semitendinosus.The beef quality is the best when the supplemental level is 130 mg/d.