Studies On Development Of A Long-Shelf-Life Organic Drinking Yoghurt

People ’s pursuit of health is increasing day.Organic foods characterized by health,environmental protection and no use of chemical pesticides and fertilizers have attracted wide attention,and the direction of yogurt market has also changed.The emergence of organic drinking yogurt with long shelf life not only meets consumers ’ demand for nutritional function and high-end,but also solves the problems of inconvenient storage and inconvenient drinking of conventional yogurt.Because of its long-shelf-life,stable quality,refreshing taste and other excellent characteristics,it can meet the needs of different consumer groups in various consumption scenarios.This article explores how to produce high-quality,safe and reliable organic drinking yoghurt with long shelf life was discussed from the aspects of formula research,process optimization and quality maintenance.The effects of different additives and different processing conditions on the quality of drinking yoghurt were explored,as well as the quality changes of drinking yoghurt at different temperatures during storage.In the study,the process characteristics of yogurt were evaluated by stability kinetic index,water holding capacity and acidity,and the stability index of storage period was evaluated by physical and chemical indexes,rheology and microbial changes.The main contents of this thesis are as follows :(1)In this study,organic raw milk and organic white sugar were selected as raw materials to carry out the research and development of organic drinking yogurt with long shelf life.It was found that different stabilizers had different effects on the stability of yoghurt.The optimum stabilizer formula was obtained by orthogonal experiment and verification : physical starch 1.53 %,pectin 0.13 %,agar 0.14 %,whey protein powder1 %.(2)Based on the above formula,the production process steps were optimized to ensure the stability of the product system by using the difference of production process and storage method between normal temperature yogurt and low temperature yogurt.It was found that different process conditions had different effects on the stability of yogurt.The optimum process parameters were obtained by orthogonal experiment and verification : the inoculation amount of strain was 40 DCU / 100 L,the homogenization pressure after fermentation was 40 bar,and the secondary sterilization condition was75 °C / 25 seconds.Such a combination of process parameters can effectively improve the quality indicators and various functional characteristics of the product,which is conducive to product development and market sales.(3)The storage period of organic drinking yogurt was monitored,covering the quantitative and qualitative analysis of microbial,chemical and sensory quality indicators.The results showed that different storage temperature and time had different effects on the stability and quality of yogurt products.The stability at 25 °C was the best,and the storage at low temperature and high temperature would affect the stability of yogurt.After 120 days of storage at 4 °C,the viscosity of yogurt began to decrease,and whey precipitation occurred.At the storage temperature of 37 °C,the viscosity of yogurt began to decrease after 60 days,and the problem of whey precipitation also appeared.During the storage period of 180 days,under the temperature conditions of 4 °C,25 °C and 37 °C,the detection amount of microorganisms such as Escherichia coli,mold and yeast was less than 1 CFU / m L,which met the requirements of national standard GB 19302.