Improving effect of soy whey‐derived peptide on the quality characteristics of functional yogurt

Abstract

The purpose of this research was to investigate the effect of bioactive peptides isolated from soy whey on the physicochemical, sensory, and microbiological characteristics of yogurt during storage. Trypsin was utilized to hydrolyze soy whey protein at 45°C for 4 h. Then, the resulting protein hydrolysate was fractionated using reversed phase‐high performance liquid chromatography (RP‐HPLC). Since the F7 fraction showed the best antioxidant and antibacterial capabilities, different levels (6.5, 13, and 17 mg/mL) of this peptide fraction were added to yogurt. A control sample (without the bioactive peptide) was also prepared. Yogurt samples were stored for 3 weeks. With the increase in peptide concentration, the antioxidant activity of yogurt increased while viscosity and syneresis decreased (p < .05). During storage, yogurt acidity, syneresis, and viscosity increased while pH and antioxidant activity declined (p < .05). The addition of bioactive peptide reduced the quantity of Escherichia coli and Staphylococcus aureus bacteria in yogurt during storage (p < .05), and the reduction in bacterial quantity was stronger as the peptide content was increased. The sample containing the largest concentration of peptide (17 mg/mL) got the lowest overall acceptability score. The level of 13 mg/mL of the peptide was chosen as the best concentration for yogurt fortification in terms of overall acceptance and functional properties. Therefore, soy whey‐derived peptide can be utilized as a functional component as well as a natural preservative in yogurt.

Enhancement of yogurt functionality by adding Mentha piprita phenolic extract and evaluation of its quality during cold storage

“…This decrease in AA is probably caused by a loss of AA of the bioactive peptides, affected by variations in amino acid content and/or changes in their sequences as a result of lower pH levels in the yogurt, which persists even during the post‐acidification period (Mashayekh et al., 2023 ). A further possible explanation might be the intensified interactions between milk proteins and the phenolic compounds contained in the incorporated extract (Vital et al., 2015 ).…”

Recent advances in exploring and exploiting soybean functional peptides—a review

“…The incorporation of 13 mg/mL of peptide showed a maximum decline in Escherichia coli (0.25 CFU/mL) and Staphylococcus aureus (0.79 CFU/mL) levels. Therefore, we conclude that soy whey-derived peptides can be used as a natural preservative of yogurt ( 124 ).…”