Improving anti-hypertensive properties of plant-based alternatives to yogurt fortified with rice protein hydrolysate

In recent years, an increasing demand of plant-based yogurt-like products for partially replacing milk products was related to both health and ethical needs. The objective of this study was to improve the functionality of yogurt-like products relevant for hypertension, using fortification with protein hydrolysate and lactic acid bacteria (LAB) fermentation of soy and Job’s tears beverages. Broken rice was hydrolysed by protease enzymes. Plant-based beverages and yogurt-like products with and without rice protein hydrolysate were prepared by LAB fermentation and evaluated by in-vitro assays for inhibition of free radical scavenging and angiotensin-converting enzyme (ACE) activity. Biochemical changes caused by lactic acid bacteria metabolism were characterized using chemical analysis and (1)H NMR. The rice protein hydrolysate obtained using Alcalase® at pH 7.0 for 2 h at 60 °C showed the highest antioxidant activity and ACE inhibition. The ACE inhibition increased by 19.52% and 34.13% in Job’s tears and soy yogurt-like products with hydrolysate, respectively. A strongly significant correlation (R(2) = 0.84) between o-phthalic dicarboxaldehyde (OPA) peptides and ACE inhibition was observed. These results indicated the promise of hydrolysate and LAB fermentation as a functional ingredient and process, respectively, for the food industry.