Biochemical studies with garlic (Allium sativum) cell cultures showing different flavour levels

Garlic (Allium sativum L) cell cultures, unorganised white as well as organised green callus, revealed a total of five amino acid precursors (methyl, propyl, allyl, cysteine sulphoxides) and two unidentified ninhydrin‐positive compounds. All the five compounds were hydrolysable by alliin lyase to yield pyruvic acid. Their relative concentration varied in the cultured systems and the explant. The total flavour substrate index in globular white callus and semi‐differentiated green callus was 4 and 13% respectively of the original explant. In contrast to the substrate levels, the specific activity of alliin lyase enzyme showed half the original activity of the garlic bulb explant. The relationship between intermediary metabolism and flavour formation was studied in these cultures with the help of 14 C‐glucose and 14 C‐methionine. The incorporation of 14 C label was lower in the protein, carbohydrate and lipid fractions with a concomitant higher incorporation in the volatile fraction of semi‐differentiated cultures, whereas this trend was reversed in the white globular callus. 14 C Conversion to the flavour fraction was much lower in the in‐vitro cultures when compared with the garlic bulb. The activity of some enzymes such as amino transferase, malate dehydrogenase, polyphenol oxidase, peroxidase, and alkaline phosphatase was higher in the cultured cells than in garlic bulb. There were differences also in the protein, free amino acid profiles and peroxidase isozymes of garlic cell cultures and the original explant.