分别以新鲜羊乳为原料、直投式混合干酪发酵剂为主发酵剂、费氏丙酸杆菌为次级发酵剂,添加不同质量比(2%、4%、6%、8%、10%)的大豆分离蛋白(Soy Protein Isolation,SPI)制作混合干酪。在干酪成熟过程中,跟踪测定硬度、咀嚼性、凝聚性、弹性、水分含量等指标,待完全成熟后,结合感官分析以确定SPI添加量对干酪品质的影响。研究结果表明:随SPI添加比例的增大,混合干酪持水性增强,硬度、咀嚼性均下降,而凝聚性、弹性无明显变化趋势。感官分析结果显示,添加4%SPI的混合干酪硬度适中,质地细腻,咀嚼感良好,色泽均,奶香味浓郁,综合评价确定4%SPI为佳添加比例。

To make mixed cheese of goat milk and soy protein isolate( SPI),fresh goat milk supplied with SPI aqueous solution in ratio of 2,4,6,8 and 10%( w/w) were used as the raw materials.Highly concentrated direct-set lactic bacteria was used as main culture.Propionibacterium freudenreichii ssp.Shermanii was used as secondary culture.Hardness,chewiness,cohesiveness,springiness and moisture of the cheese were detected during a ripening period of 70 days.It was found that the addition of SPI could enhance the water binding capacity of the mixed cheese, while decrease the hardness and chewiness.As shown in the results of sensory evaluation,the mixed cheese with 4 % SPI was described as hard and exquisite texture,high chewiness,glossy appearance,homogeneous golden color,and fuller milky flavor.Based on the results from physical and chemical analysis combined with sensory evaluation,the mixed cheese with 4% SPI was most favorable.