Browning Mechanism And Process Optimization Of Brown Yoghurt

Yogurt,which has a very high nutritional value and a variety of health functions,is a consumer favorite dairy product.In recent years,brown yoghurt has been gradually favored by consumers.Compared with traditional yoghurt,there are a lot of problems in brown yoghurt process,for example poor coagulability,whey precipitation,rough taste,lack of charred sweet flavor,batch color inconsistency and other issues.Therefore,we systematically studies and discusses the effects of browning reaction conditions,the proportion of total solids and solids in raw milk on brown yoghurt index and storage quality,and the combination of brown yoghurt stabilizers.The technological parameters and formula of brown yoghurt were determined to provide theoretical reference for the actual production of brown yoghurt.The main contents of this study are as follows:Glucose,fructose and fructose syrup were selected as reducing sugars,and browning reaction was carried out with milk at different temperatures and additions.Single factor analysis was carried out with chromaticity value as index.The results showed that the browning reaction of glucose in different concentrations was better,and the faster the browning reaction was,the higher the temperature was,and the browning reaction efficiency was the highest when the glucose content was 4%~6%.Through the analysis of orthogonal experiment,it was determined that the sensory quality of browned milk was better when the concentration of glucose was 6%,the browning temperature was 95 ℃ and the browning time was 120 min.The total solids content of raw milk with 12% total solids was 13%,14%,15% and 16% respectively by adding whey protein and adding degreasing powder and whole milk powder in different combinations.Through the study of the relationship between different total solids,protein content,protein/total solids ratio,whey protein/casein ratio and yoghurt viscosity,water holding capacity,sensory evaluation,and the influence on yoghurt,viscosity and water holding capacity during storage,the strengthening technology of yoghurt protein was determined.The ratio of protein to total solids and the ratio of whey protein to casein are only four numerical levels,and there is a one-to-one correspondence among the four numerical levels.The order of influence on viscosity was protein content > total solids content > whey protein/casein ratio.Under the same total solids and proteins,increasing the ratio of whey protein to casein can improve the water holding capacity and viscosity of yoghurt,but the water holding capacity will be greater.Based on the changes of viscosity,water holding capacity,sensory evaluation and storage quality of yoghurt after fortified protein,and considering the actual production and production cost,if high quality yoghurt is obtained,2% whey protein in the raw material of 12% total solids milk,1% defatted powder should be fortified,and the total solids of yoghurt should be contained.The volume is increased to 15%.The final yoghurt has high sensory score,good viscosity and water holding capacity.Application technology of compound stabilizer.Acetylated starch phosphate,propylene glycol alginate(PGA)and agar with synergistic effect were used as composite stabilizers.The single factor analysis was carried out to determine the usage range of three stabilizers,and the optimum proportion of stabilizers for brown yoghurt was obtained as follows: acetylated di-dian phosphate 0.98% The sensory score of yoghurt was 86.4 under the conditions of 0.15% propylene glycol alginate and 0.065% agar.The hardness and viscidity of the tested samples are better than those of the same kind on the market.