Foam Separation Of Whey Protein, Preparation Ofantioxidant Products And Improvement Of Functional Properties

Whey protein is the generalization of a kind of protein in milk whey.It is a natural natural amphiphilic mixture.It has been widely used in food,health products,cosmetics and drugs because of its high nutritional and functional properties.Yak whey water is a by-product of dairy products such as casein and butter by the by Qinghai-Tibet nomads,and is a natural scarce resource possessing a great deal of whey protein and lactose at the same time.The whey protein in yak milk was rarely utilized and was usually directly discharged as whey wastewater under the condition of lower technical,which resulted in a large amount of waste resources and pasture pollution.It was difficult to separate and extract yak whey protein from whey water with the conventional technology on whey protein separation in the life and production of Qinghai-Tibet Plateau nomads,and we have provided a simple and effective method for the separation and recovery of whey protein in yak whey water,the technology prossese the characteristics of simple equipment and strong environmental adaptability.The antioxidant products are prepared directly from the skim yak whey water and the preparation process was optimized by response surface process considering that whey waste water contains a large amount of whey protein and lactose,and lactose is a reducing sugar.A new idea was developed for the preparation of the antioxidant products from water resources.In addition,a natural and green method was proved for improving some functional properties of whey protein,suah as low antioxidant activity,solubility and poor foaming ability.The specific research content and experimental results were as follows.(1)Based on the single factor experiments,the response surface software was adopted to optimize and to investigate conditions of foam separation for whey protein,and the optimal conditions were found to be protein concentration of 120 ?g/mL,gas velocity of 310 mL/min,temperature of 41 ? and pH of 3.8,respectively.Under these conditions,the maximum recovey and maximum enrichment ratio reached 88.3% and 9.25,respectively.(2)Based on the single factor experiments,the optimum conditions for improving the solubility of whey protein were established as the ratio of 1:6,temperature of 100 ?,time of 0.5 h,pH value of 11.0,the solubility of whey protein was increased by 45.2% compared with unmodified whey protein.The optimum conditions for improving the foam characteristics were established as the ratio of 1:1,temperature of 60 ?,time of 1.0 h,pH value of 12.0,the solubility of whey protein was increased by 45.2%,the foaming property was increased by 108.65% and the foam stability was increased by 300% compared with the unmodified whey protein.(3)Based on the single factor experiments,the response surface software was adopted to optimize and to investigate conditions of preparation for antioxidant products from whey water,and the optimal reaction conditions were found to be time of 1.9 h,temperature of 111 ?,pH value of 11.5.Under these conditions,the DPPH· clearance rate of mallard reaction product was 76.12%,compared with the unmodified whey water,the DPPH· clearance rate was increased by 31.39%.Based on these processes,the formation of antioxidant products was confirmed by FIR chromatogram and gel electrophoresis.The antioxidant products of 10 ~ 20 KD,purified by the dialysis bag,found that the antioxidant activity was improved by 26.94% by comparing with unmodified whey protein from the foam separation.