Study On Quality Variation Of Retailed Fresh Beef At Different Seasons In Hot And Humid Areas And Composite Modifier Based On Fruit And Vegetable Juice

The Retailed fresh meat is rich in nutrients,high in water content,fresh in appearance,soft and juicy,which is the mainstream of consumption in the fresh meat market in China.The consumption of beef in our country is mainly the management mode of current slaughtering and selling,and it is directly sold in farm products and wholesale markets without adequate cooling after slaughter,which accounts for about 70% of market consumption.Seasonal temperature and humidity are the main factors that affect the deterioration of the quality of fresh meat.At present,there are few reports about the research on the changes of the fresh meat quality in different seasons in hot and humid regions.This study refers to the average annual temperature in hot and humid areas of 5°C(December~February),15°C(February,April and November),25°C(May,June and October)and 35°C(July~September)in hot and humid areas.The annual average humidity(80%)was set to analyze the effects of different seasons on the quality changes of fresh beef in the hot and humid regions of the South;single-factor experiments and response surface analysis methods were used to optimize the use of composite modifiers for fruits and vegetables,and beef fruits and vegetables were selected.The optimum ratio of juice composite modifier.It provides reference for the best time for edible fresh meat in different seasons in hot and humid regions,and provides an operating method for extending beef preservation period and improving tenderness.The results of the study as follows:(1)Taking fresh meat from Jinjiang Yellow Cattle as research object,study the total number of colonies and coliform bacteria of fresh meat sold at different storage temperatures(5,15,25,and 35°C)and relative humidity of 80%.The content of TBARS and TVB-N varies with storage time.The results showed that with the extension of storage time,the total number of colonies,coliforms,TBARS and TVB-N content of fresh meat at different storage temperatures showed an upward trend.The higher the storage temperature,the faster the rate of change of each indicator.To ensure the freshness and food safety of commercially available fresh beef,5°C(December-February),15°C(February,April and November),25°C(May,June and October)and 35°C(July-September)in hot and humid areas.The shelf life of retailed fresh meat in the environment cannot exceed 144,72,24 and 12 h after slaughter,respectively.(2)To study the changes of edible quality,muscle glycogen content and ultrastructure during the storage of fresh beef in different seasons in humid and hot areas,and to determine the best edible period of fresh meat quality in different seasons in humid and hot areas.The results showed that with the prolongation of storage time,the pH of fresh meat at different storage temperatures first decreased,and then increased,water loss rate and MFI content increased,and muscle glycogen content and sensory score decreased.The ultrastructure of muscle was destroyed gradually.The fresh meat stored at 35,25,15,5℃ was decreased to the lowest pH value,the highest shear force and the highest water loss rate at 12,24,48 and 72 h after slaughter,respectively.and reached the maximum stiffness stage.Combined with the comprehensive analysis of the quality change and shelf life of fresh meat sold in the market,The best edible time of fresh meat quality in the environment of 35℃(July-September)and 25℃(May,June and October)was 12 and 24 h ago.5℃(December-February)and 15℃(February,April and November)the market was 72~144 h and 48~72 h after slaughter,respectively,The best consumption period for retailed fresh meat.(3)The optimum ratio of fruit and vegetable composite modifiers was 32.9% tomato,22.86% ginger,17.35% kiwi fruit and 26.89% papaya juice,and the best added amount was 9.45%.The sensory score was 94.87.The validation experiment resulted in a sensory score of 95.85 for beef,which is close to the predicted value.Compared with the control group,the shelf life of beef treated with the composite improving agent for fruits and vegetables was prolonged by 2 days at 4°C,and the tenderness was increased by 51.82%.