|UEDA, YOSHINORI - Osaka Prefecture University|
|IHARA, HIDESHI - Osaka Prefecture University|
|IMAHORI, YOSHIHIRO - Osaka Prefecture University|
|WENDAKOON, SUMITHRA - Ryukoku University|
|TSANTILI, ELENI - Agricultural University Of Athens|
|CHAMBER, ALAN - University Of Florida|
Submitted to: Foods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2022
Publication Date: 1/26/2022
Citation: Ueda, Y., Bai, J., Ihara, H., Imahori, Y., Wendakoon, S., Zhao, W., Tsantili, E., Chamber, A. 2022. Functional characteristics of aldehyde dehydrogenase and its involvement in aromatic volatile biosynthesis in postharvest banana ripening.. Foods. https://doi.org/10.3390/foods11030347.
Interpretive Summary: This is the first report on aldehyde dehydrogenase (ALDH) function involved in aroma volatile metabolism in ripe bananas. ALDH converts aldehydes to carboxylic acids and may play a key role in the conversions between alcohols, aldehydes, carboxylic acids and esters, and formation of fruit aromas. Crude ALDH tests showed that the enzyme required NAD+ as a cofactor, and the optimum pH was 8.8. Lower molecular weight straight chain aldehydes, except ethanal, had high affinity to ALDH, while poor affinity was detected to blanched chain aldehydes. The results revealed parts of the mechanisms of flavor formation in fruit world.
Technical Abstract: Butanol vapor feeding to ripe banana pulp slices produced abundant butyl butanoate, indicating that a portion of butanol molecules was converted to butanoate/butanoyl-CoA via butanal, and further biosynthesized to ester. A similar phenomenon was observed when feeding propanol and pentanol, but was much weaker when feeding hexanol, 2-methylpropanol and 3-methylbutanol. Enzymes which catalyze the cascade reactions, such as alcohol dehydrogenase (ADH), acetyl-CoA synthetase (ACS), and alcohol acetyl transferase (AAT), have been well documented. However, aldehyde dehydrogenase (ALDH), which is presumed to play a key role in the pathway to convert aldehydes to carboxylic acids, has not been reported yet. Crude ALDH from banana pulps was extracted, the enzyme required NAD+ as a cofactor, and the optimum pH was 8.8. High affinity of the enzyme was straight chain of lower aldehydes except ethanal, while poor affinity was branched chain aldehydes.