Effect of high hydrostatic pressure on antioxidant capacity, mineral and starch bioaccessibility of a non conventional food: Prosopis chilensis seed

The aim of this work was to assess the influence of high hydrostatic pressure on antioxidant capacity, mineral and starch bioaccessibility of a non conventional food: "algarrobo" Prosopis chilensis seed. The algarrobo seed was pressurized at 500 MPa during 2, 4, 8 and 10 min. The antioxidant activity, mineral and starch content and bioaccessibility of algarrobo samples were significantly affected by the processing and digestion conditions. All treatments increased the bioaccessibility of the antioxidant activity (IC50), minerals (dialysis and solubility) and starch (resistant and digestible) compared to the untreated sample. Bioaccessibility of calcium, iron and zinc in the treated sample for 500 MPA at 10 min, expressed as percentage solubility, was several-fold higher (three, three and five times, respectively) than in the untreated sample. Similar effect was observed in IC50 value, algarrobo seed untreated sample exhibited the lowest antioxidant activity (0.11 +/- 0.005 mg/ml), and followed by all treated samples (500 MPa at 2, 4, Sand 10 min) which showed the strongest activity. In summary, the antioxidant capacity, mineral and starch content of the seed may be underestimated in the literature because the extraction solvents usually used do not allow a complete release of antioxidant compounds and, additionally, non-extractable polyphenols with a high antioxidant capacity are ignored. This correspondingly applies to the starch and mineral content. On the other hand, the analysis of in vitro digestive enzymatic extracts suggests that the antioxidant activity, minerals and starch of seed in the human gut may be higher than what might be expected from literature data based on measurements of aqueous-organic extracts. (C) 2011 Elsevier Ltd. All rights reserved.