THE EFFECTS OF ROASTING AND BOILING ONPHYTOCHEMICAL COMPOSITION OF ONION (Allium cepaL.) AND GARLIC(Allium sativum L.) BULBS

Abstract

The identification of specific compounds in onion and garlic bulbs and agronomic practices would lead to a better understanding of the physiological responses to onion consumption. Phytochemicals are biologically active compounds in plants that have some beneficial importance in industrial and medicinal sciences. The present study was undertaken to investigate the role of roasting and cooking on phytochemical compositions of onion (Allium cepa L) and garlic (Allium sativum L.) bulbs. Qualitative analysis of phytochemical screening of onion and garlic bulbs during postharvest processing using methanol and hexane extract indicated the presence of major phytochemicals including alkaloids, tannins, saponins, terpenoids, flavonoids and phenols. It was found that methanol extraction was better than hexane for phyhtochmical screening of onion and garlic bulbs. Mean comparison for quantitative analysis of crude aqueous extracts of major phytochemicals during postharvest processing of red onion and garlic bulbs have shown significant differences between raw and processed (roasted and cooked) bulb samples. However, from mean values no significant differences were found between roasted and cooked onion and garlic bulb samples. It was indicated that mean values of aqueous extracts of all measured phytochemicals were found to be decreasing during postharvest roasting and cooking. That is ANOVAfor quantitative determination of aqueous extracts of major phytochemicals during post-harvest processing of onion and garlic bulbs has shown highly significant differences among raw, roasted and boiled garlic bulbs.