通过静置法、离心法、低温法、超声法及低温-超声法制备了酱油二次沉淀样品,对比研究了其溶解性能、常规指标和氨基酸组成,通过聚类分析法对5种样品的氨基酸组成进行了分析。实验结果表明:5种方法制备的酱油二次沉淀中的蛋白质均不溶解于酸性缓冲溶液(pH<7.0),低温-超声法制备样品的蛋白质含量明显高于其他4种方法制备样品的蛋白质含量,且其相应的氨基酸组成也与其他4种方法制备样品的氨基酸组成存在明显差异。以上结果说明采用低温-超声法制备酱油二次沉淀样品更为科学和快速。

In this paper,the secondary precipitates of soy sauce were prepared by natural precipitation,centrifugation,cooling,ultrasonic,and cooling-ultrasonic coupling methods.Their solubilities,proximate indices and amino acids composition were studied comparatively.Meanwhile,hierarchical cluster analysis was conducted to analyze the differences of amino acids composition in the above secondary precipitates.Results showed that proteins in the above precipitates could not be re-dissolved in acidic buffers(pH<7.0).The content of protein in precipitate prepared by cooling-ultrasonic coupling method was higher than that in precipitates prepared by other methods.Meanwhile,its amino acids composition was obviously different from those of the other precipitates.The cooling-ultrasonic coupling method was more scientific and quick for secondary precipitate preparation.