Sensory characterization of two California-grown avocado varieties (Persea americana Mill.) over the harvest season by descriptive analysis and consumer tests.

In this work, descriptive analysis (DA) and consumer panels were conducted on "Hass" and "3-29-5" (GEM® ) avocados, grown in southern California. Both panels encompassed at least five time points across the 2019 harvest season. The DA panel identified and evaluated overall richness, creamy, smooth, watery, oily, sweet, bitter, umami, salty, astringent, buttery, nutty, and green. The texture attributes received the highest scores in both "Hass" and "3-29-5." Both varieties increased in richness, creaminess, and oiliness at harvests 5 and 6. The consumer panel found that "3-29-5" showed more changes in its eating experience over the season than "Hass," which agreed with dry weight data collected in a simultaneous analytical study. Correspondence analysis indicated that "Hass" samples had a consistent sensory profile over the harvest season, whereas "3-29-5" changed substantially, becoming more closely associated with a positive eating experience late in the harvest season. This is the first work to characterize avocado flavor over the harvest season using both trained and consumer sensory panels. PRACTICAL APPLICATION: Many aspects of avocado were found to have some impact on flavor, but textural properties were by far the most important in determining how well the fruit was liked. This information will be useful in future taste evaluations of avocado and the ongoing development of new avocado varieties.

Nectarine promotes longevity in Drosophila melanogaster.

Fruits containing high antioxidant capacities and other bioactivities are ideal for promoting longevity and health span. However, few fruits are known to improve the survival and health span in animals, let alone the underlying mechanisms. Here we investigate the effects of nectarine, a globally consumed fruit, on life span and health span in Drosophila melanogaster. Wild-type flies were fed standard, dietary restriction (DR), or high-fat diet supplemented with 0-4% nectarine extract. We measured life span, food intake, locomotor activity, fecundity, gene expression changes, and oxidative damage indicated by the level of 4-hydroxynonenal-protein adduct in these flies. We also measured life span, locomotor activity, and oxidative damage in sod1 mutant flies on the standard diet supplemented with 0-4% nectarine. Supplementation with 4% nectarine extended life span, increased fecundity, and decreased expression of some metabolic genes, including a key gluconeogenesis gene, PEPCK, and oxidative stress-response genes, including peroxiredoxins, in female wild-type flies fed the standard, DR, or high-fat diet. Nectarine reduced oxidative damage in wild-type females fed the high-fat diet. Moreover, nectarine improved the survival of and reduced oxidative damage in female sod1 mutant flies. Together, these findings suggest that nectarine promotes longevity and health span partly by modulating glucose metabolism and reducing oxidative damage.

Volatile emissions of navel oranges as predictors of freeze damage.

Volatile emissions of navel orange (Citrus sinensis L. Osbeck cv. Washington) fruit were evaluated as a means for predicting and gauging freeze damage. The fruits were subjected to -5 or -7 degrees C treatments in a laboratory freezer for various time periods of 2-9.5 h and stored at 23 degrees C for 1, 2, or 7 days, after which time the emission of volatiles from the fruit was measured. Following the final day of volatile measurements the fruits were stored at 5 degrees C for an additional 2-3 weeks and then evaluated for fruit quality characteristics. Peel injury in the form of brown lesions, drying of the juice vesicles, a decline in acidity, and a loss of flavor were observed to occur as a result of freezing. Corresponding to the loss in fruit quality were large increases in the emissions of ethanol, ethyl butanoate, methyl hexanoate, and ethyl octanoate. With the exception of methyl hexanoate, for which volatile emissions decreased during storage for 7 days at 23 degrees C, all of the other volatiles were relatively unchanged in amount by storage. Treatment at -7 degrees C caused greater injury, quality loss, and more volatile emanation than did freezing at -5 degrees C. The measurement of volatile emissions appears to be a useful approach to identify freeze-damaged navel oranges.