聚合乳清浓缩蛋白对凝固型酸奶品质特性的影响

Effect of polymerized whey protein concentrate on quality of set yogurt

以凝固型酸奶为研究对象,研究了添加聚合乳清浓缩蛋白(PWPC)和聚合热稳定型乳清浓缩蛋白(PHSWPC)对凝固型酸奶品质特性的影响。分析了不同添加量的PWPC和PHSWPC对酸奶发酵终点和后熟后酸奶的滴定酸度、黏度、持水力(WHC)、脱水收缩敏感性(STS)、硬度和微观结构的影响。结果表明,PWPC和PHSWPC的添加量对凝固型酸奶发酵终点无显著影响;后熟后酸奶的滴定酸度、黏度、硬度随着聚合乳清浓缩蛋白(PWP)的增加而增加;当PWPC和PHSWPC的添加量为16%时,酸奶的WHC显著提高(P<0.05),分别为84.16%±2.35%和85.90%±2.04%,而STS显著降低(P<0.05),分别为17.51%±0.73%和16.95%±0.38%。扫描电镜结果表明添加了PWPC和PHSWPC的酸奶的微观结构更加致密均匀。外源添加PWPC和PHSWPC可以改善凝固型酸奶的理化特性和酸奶的质构。

The objective of this study was to investigate the effect of different amounts of polymerized whey protein concentrate （PWPC） and polymerized heat stable whey protein concentrate （PHSWPC） on the quality of set yogurt. The effect of different additions of two differ- ent polymerized whey protein concentrate on the titratable acidity, viscosity, firmness, STS, WHC and microstructure of set yogurt were determined. The results revealed that the change of the dtratable acidity on fermentation end point was not significant （P~〉 0.05）. With the increase of the amount of PWPC and PHSWPC, the titratable acidity after post fermentation, viscosity and firmness of set yogurt increased. The WHC was significantly increased （to 84.16 ± 2.35% and 85.90 ± 2.04%, respectively）（P〈0.05） with addition of PWPC and PHSWPC （16%, w/v）, however the STS was significantly decreased （to 17.51 ± 0.73% and 16.95 ±0.38%, respecdvely）（P〈0.05）. Results of scanning electron microscopy indicated gel of set yogurt with PWPC and PHSWPC showed denser microstructure with smaller size of pores. These results indicated that adding appropriate PWPC and PHSWPC are conducive to physicochemical properties and quality of set yogurt.