Sakkas Lambros, Tzevdou Maria, Zoidou Evangelia, Gkotzia Evangelia, Karvounis Anastasis, Samara Antonia, Taoukis Petros, Moatsou Golfo
Laboratory of Dairy Research, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 118 55 Athens, Greece.
Laboratory of Food Chemistry and Technology, School of Chemical Engineering, National Technical University of Athens (NTUA), Laboratory of Food Chemistry and Technology, 5 Heroon Polytechniou Str., Zografos, 15780 Athens, Greece.
Foods. 2019 Aug 12;8(8):342. doi: 10.3390/foods8080342.
An objective of the present study was the enrichment of skim sheep yoghurt milk base with hydrolysates (WPHs) of whey protein concentrate (WP80) derived from Feta cheesemaking. Moreover, the use of high hydrostatic pressure (HP) treatment at 600 MPa/55 C/10 min as an alternative for heat treatment of milk bases, was studied. In brief, lyophilized trypsin and protamex hydrolysates of WP80 produced under laboratory conditions were added in skim sheep milk. The composition and heat treatment conditions were set after the assessment of the heat stability of various mixtures; trisodium citrate was used as a chelating agent, when needed. According to the results, the conditions of heat treatment were more important for the physical properties of the gel than the type of enrichment. High pressure treatment resulted in inferior gel properties, irrespective of the type of enrichment. Supplementation of skim sheep milk with whey protein hydrolysates at >0.5% had a detrimental effect on gel properties. Finally, skim sheep milk base inoculated with fresh traditional yoghurt, resulted in yoghurt-type gels with high counts of subsp. and -close to the ideal 1:1- and with a high ACE inhibitory activity >65% that were not essentially affected by the experimental factors.
本研究的一个目标是用源自菲达奶酪制作的浓缩乳清蛋白（WP80）的水解产物（WPHs）来强化脱脂绵羊酸奶乳基。此外，还研究了在600兆帕/55℃/10分钟的条件下使用高静水压（HP）处理作为乳基热处理的替代方法。简而言之，将实验室条件下生产的WP80的冻干胰蛋白酶和Protamex水解产物添加到脱脂绵羊奶中。在评估各种混合物的热稳定性后设定成分和热处理条件；必要时使用柠檬酸三钠作为螯合剂。根据结果，热处理条件对凝胶的物理性质比强化类型更为重要。无论强化类型如何，高压处理都会导致凝胶性能较差。向脱脂绵羊奶中添加超过0.5%的乳清蛋白水解产物对凝胶性能有不利影响。最后，接种新鲜传统酸奶的脱脂绵羊奶基产生了具有高计数的亚种和-接近理想的1:1-且具有大于65%的高ACE抑制活性的酸奶型凝胶，这些凝胶基本上不受实验因素的影响。
