Jwa Seung-Hoon, Kim Yong-An, Hoa Van-Ba, Hwang In-Ho
Department of Animal Science, Chonbuk National University, Jeonju 54896, Korea.
National Institute of Animal Science, Rural Development Administration, Wanju 55365, Korea.
Asian-Australas J Anim Sci. 2020 Aug;33(8):1339-1351. doi: 10.5713/ajas.19.0667. Epub 2019 Nov 12.
It is well recognized that beef cuts from a low quality grade are usually associated with tougher, drier and less flavorful. Thus, the present study aimed at investigating the combined effects of postmortem ageing and sous vide (SV) cooking followed by oven roasting or blowtorching on the eating quality of low quality grade Hanwoo beef striploins.
Hanwoo beef striploins (quality grade 3) obtained from 36 month-old Hanwoo steers were used, and the samples were chiller aged for 0 and 14 d at 4°C. After ageing, the samples were prepared into 2.5-cm steaks which were then SV cooked at 55°C for 5 h and then raised to 60°C for 1 h, and thereafter the SV-cooked the steaks were further roasted in oven for 20 min (SV+OV) or blowtorched (SV+TC) for 2 min. The cooked samples were analyzed for microbiological quality, browning index, Wanrner-Bratzler shear force (WBSF), aroma flavor compounds and sensory properties.
The SV cooking significantly reduced the WBSF values in beef samples (p<0.05). Blowtorching after SV cooking led to a browner surface of the beef steaks (p<0.05). The samples treated with SV+OV or SV+TC exhibited higher levels of Maillard reaction-derived aroma flavor compounds such as; pyrazines and sulfur-containing compounds compared to those just SV cooked. More especially, the SV+OV- or SV+TC- treated samples presented significantly higher flavor and overall acceptability scores compared to those just SV cooked (p<0.05). Ageing beef for 14 d significantly improved the tenderness by reducing the WBSF and increasing the tenderness scores.
Thus, the combination of postmortem ageing and SV cooking followed by additional treatments (blowtorching or oven roasting) could be used to improve the eating quality especially tenderness and flavor as well as overall acceptability of low grade Hanwoo beef.
众所周知，低质量等级的牛肉切块通常质地更硬、更干，风味也较差。因此，本研究旨在探究宰后成熟以及真空低温烹饪（SV）后再进行烤箱烘烤或喷火处理对低质量等级韩牛里脊的食用品质的综合影响。
使用从36月龄韩牛阉牛获取的韩牛里脊（质量等级3），将样品在4℃下冷藏成熟0天和14天。成熟后，将样品切成2.5厘米厚的牛排，然后在55℃下进行5小时的真空低温烹饪，接着升温至60℃烹饪1小时，之后将经过真空低温烹饪的牛排进一步在烤箱中烘烤20分钟（SV+OV）或喷火（SV+TC）2分钟。对烹饪后的样品进行微生物质量、褐变指数、沃纳-布拉茨勒剪切力（WBSF）、香气风味化合物和感官特性分析。
真空低温烹饪显著降低了牛肉样品的WBSF值（p<0.05）。真空低温烹饪后喷火使牛排表面颜色更深（p<0.05）。与仅经过真空低温烹饪的样品相比，经过SV+OV或SV+TC处理的样品表现出更高水平的美拉德反应衍生的香气风味化合物，如吡嗪和含硫化合物。更特别的是，与仅经过真空低温烹饪的样品相比，经过SV+OV或SV+TC处理的样品的风味和总体可接受性得分显著更高（p<0.05）。将牛肉成熟14天通过降低WBSF值和提高嫩度得分显著改善了嫩度。
因此，宰后成熟与真空低温烹饪相结合，再进行额外处理（喷火或烤箱烘烤）可用于改善低等级韩牛的食用品质，尤其是嫩度、风味以及总体可接受性。
