Seth Dibyakanta, Mishra Hari Niwas, Deka Sankar Chandra
Department of Food Engineering & Technology, Tezpur University, Napaam, Tezpur, Assam, India.
Department of Agricultural & Food Engineering, Indian Institute of Technology, Kharagpur, (WB), India.
J Sci Food Agric. 2018 Mar;98(5):1696-1702. doi: 10.1002/jsfa.8641. Epub 2017 Sep 25.
The consistency of sweetened yoghurt (misti dahi) is a desired characteristic which is attributed to the casein protein network formation during fermentation. Unfortunately, this property is lost in reconstituted sweetened yoghurt (RSY) due to the irreversible nature of protein denaturation during spray drying. Therefore, this study aimed to increase the consistency of RSY using different hydrocolloids.
The effects addition of guar gum, pectin, κ-carrageenan and gelatin (0.1%w/v each) on the physico-chemical, microbial, rheological and sensory properties of RSY were investigated. RSY with 40% total solids demonstrated the rheological properties which are very similar to those of fresh sweetened yoghurt. RSY containing different hydrocolloids further increased the rheological properties. The dynamic rheological study revealed that the magnitude of storage modulus (G'), loss modulus (G″), and loss tangent (tan δ) were significantly influenced by the addition of hydrocolloids and gelatin exhibited highest dynamic moduli in RSY. However, κ-carrageenan added RSY was preferred sensorially as the rheological properties were very close to gelatin added RSY. Addition of hydrocolloids significantly increased the starter bacteria count and pH and reduced water expulsion rate (P < 0.05).
Addition of hydrocolloids can improve the rheological properties of reconstituted yoghurt. The study concluded that the addition of κ-carrageenan showed better results in terms of rheological and sensory properties of RSY. © 2017 Society of Chemical Industry.
加糖酸奶（米斯蒂达希）的稠度是一种理想特性，这归因于发酵过程中酪蛋白蛋白质网络的形成。不幸的是，由于喷雾干燥过程中蛋白质变性的不可逆性，这种特性在复配加糖酸奶（RSY）中丧失。因此，本研究旨在使用不同的水胶体提高RSY的稠度。
研究了添加瓜尔豆胶、果胶、κ-卡拉胶和明胶（各0.1%w/v）对RSY的物理化学、微生物、流变学和感官特性的影响。总固形物含量为40%的RSY表现出与新鲜加糖酸奶非常相似的流变学特性。含有不同水胶体的RSY进一步提高了流变学特性。动态流变学研究表明，储能模量（G'）、损耗模量（G″）和损耗角正切（tan δ）的大小受水胶体添加的显著影响，明胶在RSY中表现出最高的动态模量。然而，添加κ-卡拉胶的RSY在感官上更受青睐，因为其流变学特性与添加明胶的RSY非常接近。添加水胶体显著增加了发酵剂细菌数量和pH值，并降低了排水率（P < 0.05）。
添加水胶体可以改善复配酸奶的流变学特性。该研究得出结论，就RSY的流变学和感官特性而言，添加κ-卡拉胶显示出更好的效果。© 2017化学工业协会。
