A comparison of fat composition of Japanese and long-term grain-fed Australian steers
A comparison of fat composition of Japanese and long-term grain-fed Australian steers
复制标题
DOI：
10.1016/s0309-1740(98)00065-5
复制
发表时间：
1999-01-01
期刊：
影响因子：
7.1
通讯作者：
Tume, RK
中科院分区：
文献类型：
--
作者：
Yang, A;Larsen, TW;Tume, RK
从日本四个主要品种的肉牛身上采集了皮下和肌间脂肪样本：和牛、和牛×安格斯牛、乳牛和墨累灰牛。为了进行比较，我们还收集了长期饲喂谷物(350-455天)的安格斯、泽西和安格斯×赫里福德牛以及澳大利亚短期饲喂谷物(70-100天)的墨雷青牛的屠体皮下脂肪样本。所有样品都测定了脂肪酸组成，代表性样品测定了三酰甘油组成、热性质、脂肪细胞大小以及脂肪和结缔组织含量。与主观评估时从软到非常软的日本样品相比，澳大利亚的脂肪样品一般是硬的，表面上有一些纤维。日本牛肉和澳大利亚牛肉皮下脂肪的硬度在触觉和视觉上的差异被所测定的物理和化学特性所证实。澳大利亚和日本的脂肪样品的熔化模式明显不同。与澳大利亚的样品(1.0)相比，日本脂肪的饱和脂肪酸含量低得多，而不饱和脂肪酸多得多，导致不饱和/饱和比(1.9)高得多。这主要是由于日本样品中油酸和棕榈油酸含量较高，硬脂酸含量较低所致。日本脂肪中的三酰甘油含有较少的三饱和和双饱和脂肪酸，结构中含有较多的二单不饱和和三单不饱和脂肪酸。当日本皮下脂肪样本按其肉类质量等级进行分组时，观察到了差异。从5级到2级，大理石花纹评分显著降低(9.3~2.5)，棕榈油/硬脂酸比值显著降低(1.7~1.2)，结缔组织含量增加(1.5~2.1%)。与皮下脂肪相比，肌间脂肪的饱和脂肪酸含量较高，不饱和脂肪酸含量较低，导致不饱和脂肪酸与饱和脂肪酸、棕榈油酸与硬脂酸的比值较低。结果表明，脂肪的脂肪酸组成和三酰甘油结构在决定日本市场所需脂肪的光泽、质地和性质方面起着主导作用：日本牛脂肪柔软的主要原因是硬脂酸含量低，因此熔融温度较低。脂肪细胞的大小以及脂肪的脂肪和结缔组织含量似乎不那么重要。(C)1998爱思唯尔科学有限公司。保留所有权利。
Subcutaneous and intermuscular fat samples were collected from carcases of four major breeds of steers in Japan: Wagyu, Wagyu x Angus, Dairy and Murray Grey. For comparison, we also collected subcutaneous fat samples from carcases of long-term grain-fed (350-455 days) Angus, Jersey and Angus x Hereford steers, and short-term grain-fed (70-100 days) Murray Grey steers in Australia. Fatty acid profiles were determined on all samples and triacylglycerol composition, thermal properties, fat cell size and lipid and connective tissue contents were determined on representative samples. Compared with the Japanese samples which were soft to very soft when assessed subjectively, samples of Australian fat were generally hard and somewhat fibrous in appearance. These tactile and visual differences in the hardness of the subcutaneous fat between the Japanese and Australian beef were confirmed by the physical and chemical properties determined. Markedly different melting patterns were observed for the Australian and Japanese fat samples. The Japanese fat had considerably less saturated and more unsaturated fatty acids resulting in much higher unsaturated/saturated ratios (1.9) compared with the Australian samples (1.0). This resulted primarily from the high contents of oleic and palmitoleic acids and the low content of stearic acid of the Japanese samples. The triacylglycerols from the Japanese fat had considerably less tri-saturated and di-saturated fatty acids and more di-monounsaturated and tri-monounsaturated fatty acids in their structure. Differences were observed when the Japanese subcutaneous fat samples were grouped by their meat quality grades. From Grade 5 to Grade 2, there was a significant decrease in marbling score (9.3 to 2.5) and in the ratio of palmitoleic to stearic acid (1.7 to 1.2) and an increase in the connective tissue content (1.5 to 2.1%). Compared with subcutaneous fat, intermuscular fat had a higher content of saturated and a lower content of unsaturated fatty acids resulting in a lower ratio of unsaturated to saturated fatty acids and of palmitoleic to stearic acid. It was concluded that the fatty acid composition and the triacylglycerol structure of fat plays the predominant role in determining the lustre, texture and properties of fat desired by the Japanese market: the soft character of fat from Japanese cattle results primarily from its low content of stearic acid and consequent lower melting temperatures. Fat cell size and the lipid and connective tissue contents of fat appear to be less important. (C) 1998 Elsevier Science Ltd. All rights reserved.