The present investigation was designed to evaluate the mineral element bio-accessibility and antioxidant indices of blanched Basella rubra at different phases of simulated in vitro digestion (oral, gastric, and intestinal). The phenolic composition of processed vegetable was determined using high-performance liquid chromatography (HPLC)-diode-array detection method. Mineral composition, total phenolic content (TPC), total flavonoid content (TFC), ferric reducing antioxidant power (FRAP), and total antioxidant activity (TAA) of the in vitro digested blanched and raw vegetable were also determined. HPLC analysis revealed the presence of some phenolic compounds, with higher levels (mg/g) of polyphenols in raw B. rubra (catechin, 1.12; p-coumaric acid, 6.17; caffeic acid, 2.05) compared with the blanched counterpart, with exeption of chlorogenic acid (2.84), that was higher in blanched vegetable. The mineral content (mg/100 g) showed a higher value in enzyme treated raw vegetable compared to their blanched counterparts, with few exceptions. The results revealed a higher level of some of the evaluated minerals at the intestinal phase of digestion (Zn, 6.36/5.31; Mg, 5.29/8.97; Ca, 2,307.69/1,565.38; Na, 5,128/4,128.21) for raw and blanched respectively, with the exception of Fe, K, and P. The results of the antioxidant indices of in vitro digested B. rubra revealed a higher value at the intestinal phase of in vitro digestion, with raw vegetal matter ranking higher (TPC, 553.56 mg/g; TFC, 518.88 mg/g; FRAP, 8.15 mg/g; TAA, 5,043.16 μM Trolox equivalent/g) than the blanched counterpart. The studied vegetable contains important minerals and antioxidant molecules that would be readily available after passing through the gastrointestinal tract and could be harnessed as functional foods.
Keywords: Basella rubra; antioxidant indices; bio-accessibility; mineral content; phenolic compounds.