Brodziak Aneta, Król Jolanta, Barłowska Joanna, Teter Anna, Florek Mariusz
Institute of Quality Assessment and Processing of Animal Products, University of Life Sciences in Lublin, Akademicka 13, 20-950 Lublin, Poland.
Animals (Basel). 2020 Aug 4;10(8):1350. doi: 10.3390/ani10081350.
The stability of the physicochemical characteristics of yoghurts during refrigerated storage is important for industry and the consumer. In this study we produced plain yoghurts with the addition of health-promoting whey protein concentrate (WPC), using two different starter cultures based on and subsp. . Physicochemical changes (acidity, nutritional value, water activity, water-holding capacity, texture, and colour, including whitening and yellowing indices) as well as sensory changes occurring during 28-day refrigerated storage were determined. Starter cultures were found to significantly ( ≤ 0.05 and ≤ 0.01) influence the water-holding capacity, firmness, consistency, cohesive strength and colour parameters of the curd. Use of whey protein concentrate affected both the physicochemical and sensory quality of the yoghurts. The additive had a significant effect on potential acidity, inhibiting the increase in lactic acid in the yoghurts during storage, and also reduced syneresis. However, it decreased the lightness of curd and negatively affected its sensory characteristics, primarily flavour. Moreover, nearly all parameters changed significantly with the passage of storage time (in most cases negatively). The exceptions were total protein and fat content. The changes, however, were not severe and remained at a level acceptable to tasters. Addition of 1% or 2% whey protein to yoghurt may be a good solution that can be routinely applied in the dairy industry to offer consumers a new functional product. A comprehensive assessment of the physicochemical and sensory changes occurring during refrigerated storage of yoghurts manufactured with the addition of WPC and using different cultures is crucial for modelling such a product.
酸奶在冷藏储存期间的物理化学特性稳定性对食品工业和消费者而言都很重要。在本研究中，我们添加了具有促进健康作用的乳清蛋白浓缩物（WPC）来制作原味酸奶，使用了基于嗜热链球菌和德氏乳杆菌保加利亚亚种的两种不同发酵剂。测定了在28天冷藏储存期间发生的物理化学变化（酸度、营养价值、水分活度、持水能力、质地和颜色，包括美白和变黄指数）以及感官变化。发现发酵剂对凝乳的持水能力、硬度、稠度、内聚强度和颜色参数有显著影响（P≤0.05和P≤0.01）。使用乳清蛋白浓缩物会影响酸奶的物理化学和感官品质。该添加剂对潜在酸度有显著影响，抑制了酸奶在储存期间乳酸的增加，还减少了乳清分离。然而，它降低了凝乳的亮度，并对其感官特性产生负面影响，主要是风味方面。此外，几乎所有参数都随储存时间的推移而发生显著变化（在大多数情况下是负面的）。例外的是总蛋白和脂肪含量。不过，这些变化并不严重，仍处于品尝者可接受的水平。在酸奶中添加1%或2%的乳清蛋白可能是一种很好的解决方案，可在乳制品行业常规应用，为消费者提供一种新的功能性产品。对添加WPC并使用不同发酵剂生产的酸奶在冷藏储存期间发生的物理化学和感官变化进行全面评估，对于模拟此类产品至关重要。
