Effect of Furan Fatty Acids and 3-Methyl-2,4-nonanedione on Light-Induced Off-Odor in Soybean Oil

Accelerated oxygenation for the production of fortified (mystelle-type) sweet wines: effects on the chemical and flavor profile

BACKGROUND

Fortified wine is an important category in the wine world with very famous wines such as Porto or Jerez-wine type. The quality of fortified wines increased significantly with barrel aging not only because of a long oxidation process, but also because, in Porto wines such as Ruby or Vintage styles, the long period in bottle permits their fining. Reducing the time of oxidation can favor the development of this technique even for less known sweet wines, making them good quality and less expensive. In the present study, we have used Gamay red variety subjected to postharvest controlled dehydration at 20-22 °C and 70-75% relative humidity with an airflow of 1 m s-1. Then the grapes were pressed, and alcohol was added to the must up to an alcohol content of 15.85% (mystelle-type wine). The mass was split into six glass jars, three were oxygenated (OX) and three not (Control), and the oxygenation lasted 62 days.

RESULTS

Wine that was oxygenated had a slightly higher volatile acidity, lower alcohol content (13.00%), and lower anthocyanins and polyphenols content. In term of volatile organic compounds (VOCs), the Control wine had a higher content of alcohols, whereas the OX sample had a higher content of lactones, furans and esters. Sensory evaluation confirmed the VOCs analysis; the two wines had a statistically different profile depending on the oxidation treatment. In general, OX wine was more appreciated in terms of visual attractiveness, taste and olfactory pleasantness.

CONCLUSION

In conclusion, the technique described in the present study could be a valid alternative to traditional aging of fortified sweet wines, reducing time and costs. © 2024 Society of Chemical Industry.

Mutations in the genes responsible for the synthesis of furan fatty acids resolve the light-induced off-odor in soybean oil

Soybean oil is the second most produced edible vegetable oil and is used for many edible and industrial materials. Unfortunately, it has the disadvantage of 'reversion flavor' under photooxidative conditions, which produces an off-odor and decreases the quality of edible oil. Reversion flavor and off-odor are caused by minor fatty acids in the triacylglycerol of soybean oil known as furan fatty acids, which produce 3-methyl-2,4-nonanedione (3-MND) upon photooxidation. As a solution to this problem, a reduction in furan fatty acids leads to a decrease in 3-MND, resulting in a reduction in the off-odor induced by light exposure. However, there are no reports on the genes related to the biosynthesis of furan fatty acids in soybean oil. In this study, four mutant lines showing low or no furan fatty acid levels in soybean seeds were isolated from a soybean mutant library. Positional cloning experiments and homology search analysis identified two genes responsible for furan fatty acid biosynthesis in soybean: Glyma.20G201400 and Glyma.04G054100. Ectopic expression of both genes produced furan fatty acids in transgenic soybean hairy roots. The structure of these genes is different from that of the furan fatty acid biosynthetic genes in photosynthetic bacteria. Homologs of these two group of genes are widely conserved in the plant kingdom. The purified oil from the furan fatty acid mutant lines had lower amounts of 3-MND and reduced off-odor after light exposure, compared with oil from the wild-type.