Abstract: The objective of this paper is to produce a new yogurt containing purple sweet potato extract (PSPE) rich in anthocyanins (PSPE-A) and casein hydrolysate rich in angiotensin converting enzyme (ACE) inhibitory peptides (CH-A) based on ordinary yoghurt processing, and to evaluate its anti-hypertensive and hepatoprotective effects using animal model. Spontaneously hypertensive rats (SHR) were orally administered with yogurts containing 3.0 g of CH-A and 1.5 g of PSPE-A (treatment 1) or 3.0 g of CH-A and 3.0 g of PSPE-A (treatment 2) at a dosage of 3.33 g/kg. Results showed that at 4 h after administration, systolic blood pressure (SBP) of SHR in treatments 1 and 2 was decreased by (23.13 ± 2.41) and (26.23 ± 1.44) mm Hg, respectively. The SHR were orally administered with the yoghurts at a dose of 3.33 g/kg for 30 days to evaluate their hepatoprotective effect against alcoholic liver damage. Results showed that among five tested indexes, namely aspartate transaminase (AST), alanine transaminase (ALT), triglyceride (TG), malondialdehyde (MDA) and reduced glutathione (GSH), at least three indexes such as AST, ALT and MDA were improved significantly (P < 0.05). Both yogurts improved the hepatic cells and fat metabolism as evidenced by histopathological examination. Therefore, yoghurt containing purple sweet potato extract rich in anthocyanins and casein hydrolysate rich in ACE exerts antihypertensive and hepatoprotective effects in the experimental dosage range.

Key words: purple sweet potato extract, anthocyanins, casein hydrolysate, angiotensin converting enzyme inhibitory peptides, yogurt, antihypertensive effect, hepatoprotective activity