Effects of polymerized goat milk whey protein on physicochemical properties and microstructure of recombined goat milk yogurt

Abstract

Goat milk whey protein concentrates were manufactured by microfiltration (MF) and ultrafiltration (UF). When MF retentate blended with cream, which could be used as a starting material in yogurt making. The objective of this study was to prepare goat milk whey protein concentrates by membrane separation technology and to investigate the effects of polymerized goat milk whey protein (PGWP) on the physicochemical properties and microstructure of recombined goat milk yogurt. A 3-stage MF study was conducted to separate whey protein from casein in skim milk with 0.1-µm ceramic membrane. The MF permeate was ultrafiltered using a 10 kDa cut-off membrane to 10-fold, followed by 3 step diafiltration. The ultrafiltration-diafiltrationtreated whey was electrodialyzed to remove 85% of salt, and to obtain goat milk whey protein concentrates with 80.99% protein content (wt/wt, dry basis). Recombined goat milk yogurt was prepared by mixing cream and MF retentate, and PGWP was used as main thickening agent. Compared with the recombined goat milk yogurt without PGWP, the yogurt with 0.50% PGWP had desirable viscosity and low level of syneresis. There was no significant difference in chemical composition and pH between the recombined goat milk yogurt with PGWP and control (without PGWP). Viscosity of all the yogurt samples decreased during the study. There was a slight but not significant decrease in pH during storage. Bifidobacterium and Lactobacillus acidophilus in yogurt samples remained above 10 6 cfu/g during 8-wk storage. Scanning electron microscopy of the recombined goat milk yogurt with PGWP displayed a compact protein network. Results indicated that PGWP prepared directly from raw milk may be a novel protein-based thickening agent for authentic goat milk yogurt making.

Technological challenges in production of goat milk products and strategies to overcome them: a review

“…The desirable textural attributes of yogurt are high viscosity, smoothness, and thickness. Yogurt prepared from goat milk possesses a soft body, lower viscosity, and reduced water‐holding capacity (Tian et al ., 2022). This is majorly due to differences in casein content of goat milk (Tian et al ., 2022).…”

“…Yogurt prepared from goat milk possesses a soft body, lower viscosity, and reduced water‐holding capacity (Tian et al ., 2022). This is majorly due to differences in casein content of goat milk (Tian et al ., 2022). Goat milk has a lower concentration of α s1 ‐casein, which plays a pivotal role in the formation of firm gel, coagulum, and denser network of fermented dairy products, resulting in weak texture of goat milk yogurt.…”

“…The most sensorially acceptable yogurt was obtained by the addition of skim milk powder into an admixture of goat and cow milk (50:50) (Gursel et al ., 2016). The addition of polymerised whey proteins, singly, or with pectin as a co‐gelling agent enhances the viscosity as well as water holding capacity of goat milk gel (Wang et al ., 2012; Tian et al ., 2022). This was attributed to the interactions between casein and whey proteins thereby, forming a denser and highly connected network.…”

Production of yogurt from goat and sheep milk with a fruit and berry concentrate

“…Organoleptic evaluation showed that encapsulation in general can increase customer satisfaction. It can be argued that masking the color and taste of microalgae by microencapsulation can be used to enrich dairy products with microalgae [10].…”

A study of the physico-chemical composition and technological properties of sheep and goat milk (ShGM) depending on the breed of the animal

“…So, for example, an interesting direction is the preparation of whey protein concentrates from goat's milk. The concentrates were produced by membrane separation and the study of the effect of polymerized whey protein of goat milk on the physicochemical properties and microstructure of recombined goat milk yogurt [16]. The results indicated that polymerized whey protein made directly from raw milk could be a novel protein-based thickener for natural goat milk yogurt.…”