Gyawali Rabin, Ibrahim Salam A
Food Microbiology and Biotechnology Laboratory,Food and Nutritional Science Program,North Carolina A&T State University,Greensboro,NC 27411-1064.
J Dairy Res. 2018 May;85(2):238-242. doi: 10.1017/S0022029918000109.
The objective of the study reported in this Research Communication was to investigate the effects of pectin and whey protein concentrate (WPC) on the generation of acid whey during Greek-style yogurt (GSY) processing. Yogurt samples were prepared using pectin (0·05%, w/v) and whey protein concentrate (WPC-80) (1%, w/v) as possible ingredients that reduce the acid whey production. Control yogurt sample was prepared without addition of these ingredients. The results showed that yogurt made with pectin plus WPC had significantly higher water holding capacity (~56%) than the control (33%). Similarly, yogurt supplemented with pectin plus WPC exhibited 15% less susceptibility to syneresis compared to the control (P < 0·05). Viability of L. bulgaricus and S. thermophilus in all yogurts remained ≥7·0 and ≥8·0 log CFU/g respectively. Native PAGE analysis showed an interaction between pectin and WPC. Pectin hinders the formation of large oligomeric aggregates of whey protein which correlates with an increase in WHC and a decrease in syneresis. Our results demonstrated that a combination of pectin and WPC have the potential to limit the quantity of acid whey generation in GSY manufacturing. Thus, these ingredients have positive implications for dairy industry in the production of GSY.
本研究通讯中报道的研究目的是调查果胶和浓缩乳清蛋白（WPC）对希腊式酸奶（GSY）加工过程中酸性乳清生成的影响。使用果胶（0.05%，w/v）和浓缩乳清蛋白（WPC - 80）（1%，w/v）作为可能减少酸性乳清产生的成分制备酸奶样品。对照酸奶样品在不添加这些成分的情况下制备。结果表明，用果胶加WPC制成的酸奶持水能力显著更高（约56%），高于对照（33%）。同样，与对照相比，添加果胶加WPC的酸奶脱水收缩敏感性降低了15%（P < 0.05）。所有酸奶中保加利亚乳杆菌和嗜热链球菌的活力分别保持≥7.0和≥8.0 log CFU/g。天然聚丙烯酰胺凝胶电泳分析表明果胶和WPC之间存在相互作用。果胶阻碍了乳清蛋白大寡聚体聚集体的形成，这与持水能力增加和脱水收缩减少相关。我们的结果表明，果胶和WPC的组合有可能限制GSY生产中酸性乳清的生成量。因此，这些成分对GSY生产中的乳制品行业具有积极意义。
