乳清分离蛋白对鲜榨黄冠梨汁澄清效果的研究
Effect of whey protein isolate on clarification of fresh Pyrus bretschneideri ‘Huangguan'pear juice
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摘要: 为了探究乳清分离蛋白（whey protein isolate,WPI）对鲜榨黄冠梨汁的澄清效果,在单因素实验的基础上应用响应面法对鲜榨梨汁的澄清条件进行优化,并对比研究WPI、果胶酶、WPI+果胶酶3种处理方法对梨汁澄清度和褐变度的影响。优化的澄清条件为WPI添加量0.69%,处理时间90 min,处理温度60℃,该条件下梨汁透光率为87.9%。3种方法处理后梨汁澄清度的大小顺序为WPI+果胶酶>WPI>果胶酶,褐变度的大小顺序为果胶酶>WPI>WPI+果胶酶。这表明WPI对鲜榨黄冠梨汁具有澄清和抑制褐变的双重作用,效果优于果胶酶,与果胶酶联合处理,效果更佳。Abstract: The effect of whey protein isolate( WPI) on clarification of fresh‘Huangguan'pear juice was evaluated.Based on the single factor experiments,the response surface methodology was employed to optimize the clarification conditions of pear juice and the effects of WPI and pectinase treatments alone and combined on clarity and browning degree of pear juice were also studied.The optimum conditions for clarification of pear juice were as follows: the concentration of WPI 0.69%,treatment time 90 min and treatment temperature 60 ℃.Under the conditions,the transmittance of pear juice was 87.9%.The order of clarity of pear juice treated by the three methods was WPI- pectinase > WPI > pectinase. The order of browning degree of pear juice treated by the three methods was pectinase > WPI > WPI- pectinase. The results suggested that WPI had dual effects of clarification and inhibition of browning on fresh‘Huangguan'pear juice.Moreover,WPI acted more effectively than pectinase.In addition,the effect of WPI combined with pectinase treatment was better than the effect of WPI treatment alone.
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