Influence of processing on the phenolic compounds of feijoa pulp (Feijoa sellowiana)

Abstract

Herbal teas are globally popular among health conscious consumers. In this study the phenolic content and potential antioxidant activities of bael fruit herbal tea prepared with dried immature bael fruit cuts (Aegle marmelos), traditionally used in the Asia, were determined. Phenolic compounds of the herbal extracts were identified using liquid chromatography-tandem mass spectrometry. The total phenolic content (TPC) and antioxidant activities of the tested herbal extract was determined. The amount of herbal material to be used in the tea preparation was established based on the sensory evaluation conducted with 50 untrained adult panelists. The single dose efficacy of the bael fruit herbal tea on postprandial glycemic response and plasma antioxidant capacity (PAC) of healthy adults were investigated. A randomized crossover study was carried out with 16 healthy adults who consumed 250 mL bael fruit tea with 50 g glucose challenge and the control (50 g glucose in 250 mL water) randomly within two visits. Blood samples were collected at the baseline and postprandial at 30, 45, 60, 90, and 120 min using microcapillary tubes. The plasma was analyzed for glucose concentration (PGC) and PAC. The TPC of bael fruit tea extract was 108.3 μmol gallic acid equivalents/g of extract. There was a reduction trend in mean PGC of those subjects who consumed bael fruit tea compared to the glucose added water (control) at each time point. Furthermore, the bael fruit tea significantly increased PAC at the end of 120 min post ingestion. Further research is warranted to examine the long-term efficacy of multiple dose ingestion of bael fruit herbal tea in the control and management of diseases associated with oxidative stress.