Massey Institute of Food Science and Technology.
Riddet Institute, Massey University, Palmerston North, New Zealand.
J Nutr. 2018 Oct 1;148(10):1564-1569. doi: 10.1093/jn/nxy153.
Cooking processes affect the physical, chemical, and structural properties of meat proteins. Cooking may also affect the protein quality of meat, as indicated by the true ileal digestibility of individual amino acids, the content of each truly digestible amino acid, and the digestible indispensable amino acid score (DIAAS).
The study aimed to determine the effect of the cooking process (raw, not cooked; boiled; grilled; pan-fried; roasted) of beef on true (standardized) ileal amino acid digestibility, true ileal digestible amino acid content, and DIAAS.
Beef topside steak was subjected to one of the following conditions: raw, boiled, grilled, pan-fried, or roasted, followed by mincing. The growing pig was used as an animal model for the adult human. Diets containing the raw or cooked meats (10% crude protein content) were fed to growing pigs (n = 6 per diet; mean ± SEM bodyweight, 23.6 ± 0.48 kg) and samples of terminal ileal digesta were collected under anesthesia. True ileal amino acid digestibility of the beef was determined and DIAAS values were calculated.
There were only minor differences in true ileal amino acid digestibility across cooking conditions with all amino acids having true ileal amino acid digestibility in the range of 90-100%. In general, boiled meat had the highest true ileal digestible amino acid content (total of 724 g/kg dry matter), and roasted meat the lowest (total of 641 g/kg dry matter; P < 0.001). The DIAAS was greater (P < 0.001) for the raw, boiled, and pan-fried meat treatments (97-99%) than for roasted meat (91%) or grilled meat (80%). The high DIAAS (range 80-99%) across cooking conditions confirms that bovine meat is a high-quality protein source.
Cooking conditions affect the true ileal digestible amino acid content and DIAAS of beef, as determined with the use of the pig model.
烹饪过程会影响肉蛋白的物理、化学和结构特性。烹饪还可能影响肉的蛋白质质量，这可以通过个别氨基酸的回肠真消化率、每种真正可消化氨基酸的含量以及可消化必需氨基酸评分（DIAAS）来衡量。
本研究旨在确定牛肉的烹饪过程（生的、未煮的；煮的；烤的；煎的；烤的）对回肠真（标准化）氨基酸消化率、回肠真可消化氨基酸含量和 DIAAS 的影响。
将牛臀肉置于以下一种条件下：生的、煮的、烤的、煎的或烤的，然后切碎。生长猪被用作成人的动物模型。含有生肉或熟肉（10%粗蛋白含量）的饮食被喂食给生长猪（每组 6 只；平均体重 ± SEM，23.6 ± 0.48 kg），并在麻醉下收集末端回肠食糜样本。测定牛肉的回肠真氨基酸消化率，并计算 DIAAS 值。
在所有氨基酸的回肠真氨基酸消化率均在 90-100%范围内，烹饪条件对回肠真氨基酸消化率的差异很小。一般来说，煮肉的回肠真可消化氨基酸含量最高（总含量为 724 g/kg 干物质），烤肉的含量最低（总含量为 641 g/kg 干物质；P < 0.001）。生肉、煮肉和煎肉处理的 DIAAS 更高（P < 0.001）（97-99%），烤肉（91%）或烤肉（80%）。不同烹饪条件下的高 DIAAS（范围 80-99%）证实了牛肉是一种高质量的蛋白质来源。
使用猪模型，烹饪条件会影响牛肉的回肠真可消化氨基酸含量和 DIAAS。
