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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Citrus and Other Subtropical Products Research » Research » Publications at this Location » Publication #406475
Research Project: Determination of Flavor and Healthful Benefits of Florida-Grown Fruits and Vegetables and Development of Postharvest Treatments to Optimize Shelf Life an Quality for Their Fresh and Processed Products

Location: Citrus and Other Subtropical Products Research

Title: Functional characteristics of aldehyde dehydrogenase and its involvement in aroma volatile biosynthesis in banana fruit

Author
item UEDA, YOSHINORI - Osaka Prefecture University
item Zhao, Wei
item IHARA, HIDESHI - Osaka Prefecture University
item IMAHORI, YOSHIHIRO - Osaka Prefecture University
item TSANTILI, ELENI - Agricultural University Of Athens
item WENDAKOON, SUMITHRA - Osaka Prefecture University
item CHAMBERS, ALAN - University Of Florida
item Bai, Jinhe

Submitted to: Proceedings of Florida State Horticultural Society
Publication Type: Proceedings
Publication Acceptance Date: 12/1/2023
Publication Date: 12/31/2023
Citation: Ueda, Y., Zhao, W., Ihara, H., Imahori, Y., Tsantili, E., Wendakoon, S., Chambers, A., Bai, J. Functional characteristics of aldehyde dehydrogenase and its involvement in aroma volatile biosynthesis in banana fruit. Proceedings of Florida State Horticultural Society. 136:153. 2023.

Interpretive Summary:

Technical Abstract: Many enzymes regarding the conversions between volatile alcohols, aldehydes/ketones, acids, and esters have been studied extensively in fruits and plants, and/or adapted from microorganism studies. In banana fruit ripening, gene expression and enzyme activity of alcohol dehydrogenase (ADH, short and medium chains) which facilitates the interconversion between alcohols to aldehydes, acyl-CoA synthetase (ACS) which activates carboxylic acids to acyl-CoAs thus can be used to biosynthesize esters, and alcohol acetyl transferase (AAT) which catalyzes ester biosynthesis, have been intensively studied. Aldehyde dehydrogenase (ALDH) dehydrogenizes aldehydes to carboxylic acids in different plant tissues. Our group first reported the function of aromatic volatile biosynthesis in bananas. Straight and branched chain C2-C6 aldehyde vapor feeding to ripe banana pulp produced their corresponding carboxylic acids. Hexanal had the highest conversion rate, followed by C3-C5 aldehydes, and ethanal had the lowest conversion rate. Generally, straight chain aldehydes had higher conversion rate than the branched chain ones when the total carbon number was the same in the molecule. The conversion is an oxygen-independent metabolic pathway and is enzyme-catalyzed with NAD+ as the cofactor. Crude ALDH was extracted from ripe banana pulps, and the interference from ADH was removed by two procedures: 1) washing off elutable proteins which contain 95% of ADH, but only about 40% of ALDH activity, with the remaining ALDH extracted from the pellet residues at the crude ALDH extraction stage; 2) adding an ADH inhibitor in the reaction mixture. The optimum pH of the ALDH was 8.8, and the optimum phosphate buffer concentration was higher than 100 mM. Further research is needed to confirm if ALDH is an enzyme in the routine pathway for volatile production associated with fruit ripening or just a consequence of aldehyde scavenging. Plants encompass a total of fourteen ALDH protein families. Nevertheless, the existing data on published superfamily genes and enzymes do not indicate any functions related to the dehydrogenization of carbon 2-6 straight and branched-chain aldehydes or their subsequent synthesis into esters in bananas and other fruits.