Effects of Food Processing on Antinutrients HCI Extractable Minerals And In Bioaccessibility of Some Micronutients In Indiginious Leafy Vegatables

Abstract

This study was undertaken to determine the effects of blanching and fermenting on phytic acid, polyphenols and HCI-extractability of Fe, Ca, Mg and P in Amaranthus hybridus (pigweed) and Solanum nigmm (black nightshade). The effects of food processes such as cooking, oven drying, sun drying and shade drying on concentration and in vitro bioaccesibility of iron, carotenoids and flavonoids in Solammz scabrum and Solanum villosum were also studied. Blanching of the leaves in steam for 90 seconds and spontaneous fermentation of the blanched and unblanched leaves was undertaken. Blanching and fermentation caused a significant reduction (P<0.05) in polyphenols and phytic acid contents in Amaranthus hybridus and Solanum nigrum leaves. There was no significant difference (P<0.05) in the amount of polyphenols and phytic acid reduced among the blanched, unblanched fermented, and blanched fermentated samples. Blanching reduced the polyphenol contents by 13.6 % and the fermentated samples reduced by 34.9% in Amaramhus hybridus and Solarmm nigrum leaves. The phytates content in Solanum nigrum was reduced by 40.4% in the blanched leaves while in Amaranthus hybridus fermentation had a reduction of 53.8%. Blanching and femientation showed significant reduction (P<0.05) in the mineral contents but significantly increased (P<0.05) the HC1-extractability of minerals in Amaranthus hybridus and Solanum nigrum. Blanching reduced the mineral contents by 20% in Solanum nigrum and 20% in Amaranthus hybridus. Fermentation reduced the mineral content by 40% in Amaranlhus hybridus and 44% in Solanum nigrum. The HCl-extractability of minerals was increased by 46% and 41% in the blanched and fermented samples of Amaranthus hybridus and Solanum nigrum. When drying in direct sun and under shade reduced the concentrations of carotenoids and flavonoids oven drying and cooking showed minimal effects on the concentrations of these micronutrients in Solanum scabrum and Solamrm villosum, In vitro bioaccessibility of carotenoids, flavonoids and iron were significantly increased by cooking of Salanum scabrum and Salanum villosum leaves. The data was subjected to Analysis of Variance by General Linear Model of the SPSS (Version l 1.5). Means separation was done by Duncan’s Multiple Range Test and the level of significance was determined at or = 0.05. Therefore fermentation, blanching and cooking processes play important roles in increasing the bioaccessibility of micronutrients in leafy vegetables and these techniques could be instrumental in alleviating the disease states associated with micronutrient deficienciecy