Plant protein enrichment effect on the physical, chemical, microbiological, and sensory characteristics of yogurt

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

New functional food products with health benefits are currently in high demand among health-conscious consumers. The present research aims to improve the functional properties of yogurt by adding peppermint hydroethanolic extract (PHE) at different doses. The impact of PHE (0%, 2%, 4%, and 6%) on yogurt was studied for acidity, pH, organoleptic quality, antioxidant activity, lipid peroxidation, and fatty acid profile. The results revealed that PHE is rich in phenolic compounds, of which rosmarinic acid was the main one (339.88 mg/g lyophilized extract) and has considerable antioxidant potential, which remarkably (p < .01) increased antioxidant capacity in yogurt by over 39.51%, even at a low dose of 2%, giving the product better protection against lipid peroxidation and preserving its physicochemical and sensory quality. At 4%, PHE increased significantly (p < .01) the content of omega-3 fatty acids, notably alpha-linolenic acid, in fortified yogurt compared with the control, and reduced (p < .01) the ratio of omega-6/omega-3, which dropped from 5.21 to 4.11. It looks feasible to prepare a yogurt with health-giving properties by adding Mentha piperita hydroethanolic extract at a concentration of up to 4% as an alternative to synthetic antioxidants, which would also extend its shelf life.

Application of plant-based proteins for fortification of oat yogurt storage stability and bioactivity

The purpose of this study was to evaluate the addition of plant-based peanut protein isolate (PNP) and commercial pea protein (CPP) on the quality of oat yogurt (OY). PNP and CPP were partially characterized for techno-functional properties. PNP had higher solubility (acidic and basic regions) and emulsifying activity than CPP. The water absorption capacity of CPP is significantly (p < 0.05) higher than PNP. Amino acid profiles of PNP and CPP were promising for the nutritional enhancement of OYs. OYs with PNP or CPP (0.5, 1, 2% w/v) were stored for 21 days and compared to the control group with no protein. On the 21st day of storage, (i) PNP- or CPP-added OYs were found to be comparable to the control with respect to post-acidification and viscosity, (ii) syneresis was more evident in PNP-added OYs than in CPP-added ones, (iii) total color change of 1% CPP-added OY was equal to the control, and (iv) hardnesses of control, 2% PNP, and 2% CPP-added OYs were 0.29 ± 0.00, 0.39 ± 0.01, and 0.45 ± 0.00 N, respectively. No adverse sensory effects were detected for CPP or PNP addition. Both proteins increased the total phenolic, soluble protein, antioxidant, antihypertensive, and α-glucosidase inhibition activity of oat milk and OYs, with PNP superior to CPP overall. Compared to oat milk, the fermentation process increased ACE inhibition activity in in vitro digested samples, whereas it reduced digested yogurts' antioxidant activity. Utilization of PNP in OY can solve the waste problem of peanut producers and the texture problem of the OY producers while formulating a functional product. PRACTICAL APPLICATION: Plant-based (PB) yogurts have a growing consumer demand. The low-protein content of PB yogurts results in low acceptance with respect to their undesirable textural and sensorial attributes. This study provided a technical basis for the PB yogurt manufacturers focusing on the addition of commercial pea protein and isolated peanut protein into oat yogurt formulation without any thickeners or flavors. In vitro digestion of protein-added oat milk and oat yogurts showed the benefits of fermentation on bioactivity to the consumers.