In vitro bioaccessibility of phenolic compounds and alpha-glucosidase inhibition activity in yoghurts enriched with mango peel powder

This study investigated the potential health benefits and functional properties of mango peel powder(MPP)as a source of antioxidants and alpha-glucosidase inhibitors in yoghurts with probiotic bacteria.The study involved plain yoghurt(PY,control),yoghurt fortified with 2%mango peel powder(MY),and yoghurt fortified with 2%MPP and 1%of each probiotic culture of L.casei,L.rhamnosus,B.lactis(MPY).Bioactive potential and individual polyphenols in the products were analysed before and after in vitro gastrointestinal digestion.Results showed that both MY(0.26±0.02 mg/g GAE)and MPY(0.28±0.04 mg/g GAE)had significantly(p≤0.05)higher phenolic contents than PY(0.17±0.02 mg/g GAE).Among the 15 quantified phenolic compounds,quercetin-3-rhamnoside was highest in MPP(432.86±11.02 mg/100g dry wt.),followed by MPY(47.97±1.20)and MY(34.44±2.76 mg/100g fresh wt.).The quantities of the major individual phenolic compounds declined significantly(p<0.05)in MPP only after gastric digestion,while remained stable in MY and MPY.There were significant(p≤0.05)increments inα-glucosidase inhibition activity(6.06%and 8.47%,in MY and MPY,respectively)post intestinal digestion.The LC-ESI-QTOF-MS/MS analysis of all the sample extracts(undigested and digested)identified a total of 108 phenolic metabolites including 33 phenolic acids,42 flavonoids,11 lignans,3 alkylphenols,4 coumarins,3 tyrosols,1 stilbene,2 xanthones,4 phenolic terpene,and 3 tyrosols,2 hydroxybenzoketones,1 hydroxybenzaldehyde and 2 other phenolic metabolites.This study provides scientific evidence for the utilization of MPP fortified yoghurts as functional food products.