Study of volatile compound formation in oxidized lipids and volatile compound retention in processed orange juice.

摘要

The production of volatile off-flavor compounds by lipid autoxidation is one of the most widely recognized quality concerns in foods.; Soybean oil, peanut oil and lard containing 0 to 10 ppm chlorophyll was stored under light for 7 to 10 days at 4, 20 and/or 40°C. Headspace volatile compounds were collected by solid phase microextraction and analyzed by gas chromatography and mass spectroscopy. Volatile compounds in soybean oil, peanut oil and lard with or without added chlorophyll were qualitatively similar after 7 to 10 days of light exposure. The presence of 5 and 10 ppm chlorophyll in soybean oil, peanut oil and lard significantly increased the production of approximately half of the volatile compounds in the soybean oil and lard after only 1 to 2 days of light exposure. The amounts of pentane, pentanal, 1-pentenol, 2-pentanal, hexane, 1-hexane, 2-hepanal, heptanal, 2-heptanal, 2-pentyl furan, 2,4,-heptadienal, 2,4-nonadienal, 1-octen-3-ol and 2-octenal in the lipids were significantly affected by chlorophyll concentration and are likely primary products of singlet oxygen oxidation. The presence of chlorophyll was the most significant factor to the amount of chlorophyll sensitive compounds produced in soybean oil during the first 2 days of light exposure; however, temperature was the most significant factor after 2 days of light exposure. Fatty acid composition was a significant factor in the amounts of volatiles produced in lipids containing chlorophyll indicating that autoxidation reactions are an important contributor to the production of volatile compounds imitated by photosensitized reactions.; Orange juice is the most predominant fruit juice in the U.S. market today. Commercial orange juice is thermally processed to inactivate pectinmethylesterase (PME) and spoilage organisms. However, thermal processing can be detrimental to the organoleptic and nutritional qualities of the juice.{09}Previous research showed that the addition of CO₂ to orange juice prior to high pressure processing (HPP) resulted in decreased volatiles after processing relative to the HPP alone. HPP in combination with added CO_2(g) was examined for efficacy in inactivating Valencia orange juice PME. Post-process chemical changes in ascorbic acid and headspace volatiles were evaluated in HPP treated samples, with and without added CO_2(g). (Abstract shortened by UMI.)