Why greening in garlic and pinking in onion occur after processing?
Jung-Eun Cho, Eun-Jin Lee, Kil-Sun Yoo, and Seung-Koo Lee
Abstracts of 27th International Horticultural Congress & Exhibition (IHC 2006), August 13-19, 2006, COEX (Convention & Exhibition), Seoul, Korea. 494 pages.
2006
บทคัดย่อ
Why greening in garlic and pinking in onion occur after processing?
Garlic (Allium sativum L.) and onion (Allium cepaL.) develop green and pink discoloration after processing. This discolorations is known to originate from reactions of the enzyme (alliinase) with the flavor precursor compounds alk(en)yl cysteine sulfoxides (ACSOs), especially 1-propenyl cysteine sulfoxide (1-PeCSO, isoallin). Despite having a similar structure, generated pigments are green in garlic and pink in onion. In an attempt to understand differences in the mechanism of color formation, model solutions were made by mixing heated onion extracts and crude garlic enzyme (alliinase) in different ratios. When crude garlic enzyme concentration was high, green pigment was formed, but when the concentration of heated onion extracts was high, a pink color was formed. Color variation was assumed to be caused by the rations of enzyme concentrations incooked onion extracts. We postulate that green discoloration occurred in garlic containing trace amount of 1-PeCSO and high amounts of alliinase, while pink coloration occurred in onion with high amounts of 1-PeCSO and low amount of alliinase.