Studying an effect of thermal treatment methods on physico-chemical properties of beef depending on aging technology

Modern methods for aging and thermal treatment facilitate an improvement in beef sensory properties. The aim of the research was to study an effect of different types of thermal treatment on quality of steaks from dry-aged beef. Steaks were obtained from the rib cut from carcasses of grain-fed young bulls; aging duration was 35 days (temperature 0–1 ºС, air relative humidity 74–75%). Aging duration in the control sample was five days (temperature 0–4 ºС, air relative humidity 80–85%). The methods for thermal treatment were as follows: sous vide cooking at 58 ºС, grill heating at 250 ºС, sous vide cooking in combination with grill treatment. During processing, the following parameters were controlled: weight loss by the direct method, hydrophobicity of myofibrillar proteins by the reaction with bromophenol blue, soluble collagen by the method of acid hydrolysis with determination of oxyproline, mass fraction of moisture and fat by the method from one analytical unit, sensory properties by the reference method. According to the data obtained, minimal losses (6.8%) were noticed upon sous vide cooking of dry-aged beef steaks. In combined heating and dry heating on grill, they increased by 6.1% and 12%. More significant weight losses were observed in beef steaks with aging time of five days upon any tested treatment types. For dry-aged beef steaks treated by sous vide and combined heating, a higher content of soluble collagen compared to other samples was established. The results of measuring mass fraction of moisture and fat indicate an increase in the nutritional value of dry-aged beef steaks. According to the total data obtained with consideration for the results of sensory evaluation, dry-aged beef steaks subjected to sous vide cooking with the following short-term dry heating on grill have higher quality.