Effect of Thermal Processing on the <em>In Vitro</em> Bioavailability of Minerals and Anti-Nutritional Factors in Indian Almond (<em>Terminalia catappa</em>) Nut

Abstract

Terminalia catappa L. (Indian almond) is an underutilized crop rich in minerals, but investigation and information on the bioavailability of minerals and the presence of anti-nutritional factors in the nut are lacking. Several traditional foodprocessing methods are used domestically to enhance the bioavailability of micronutrients and decrease the effects of anti-nutrients in plant-based diets. This study was carried out to determine the effect of thermal processing on antinutritional factors and in vitro digestibility of minerals of Terminalia catappa nuts. The mineral concentration (Na, Ca, P, Mg, Cu, Fe, and Zn) of raw and processed T. catappa seed were determined. The mineral concentration of the raw T. catappa nut was significantly higher (p<0.05) than those of processed nuts. The pressure cooking led to the highest loss in mineral content, followed by boiling, drying, and roasting in descending order. A similar pattern was observed in the digested sample except for Ca and P, which occurred the least in boiled nuts. Mineral digestibility was generally low in the raw T. catappa nut. The various processing methods employed had different effects on the digestibility of the different minerals. There was a reduction in the concentration of the anti-nutrients in the processed samples. The highest reduction in tannin and phytic acid occurred in boiled samples, followed by pressurecooked and roasted ones. The thermal processing methods which enhanced the digestibility of minerals of T. catappa nut were those that showed the greatest significant reduction of the anti-nutrients in the nuts of Terminalia catappa.