SENSORY AND AROMA PROFILING OF FRESH AND STORED 'OR' MANDARINS

‘Or’ is considered the best mandarin cultivar in Israel, and redeems exceptional high profits in export markets due to its excellent taste and flavor. In the current study, we evaluated the sensory preferences of ‘Or’ mandarins by a trained taste panel and correspondingly evaluated the biochemical composition of its juice vesicles, including sugars, acids, and aroma volatile contents at the day of harvest and following a 6-week storage period at 5°C of control untreated and wax coated fruit. Sensory evaluations rated fruit flavor as “good” to “excellent”, “good” and “fair” at the day of harvest and after 6 weeks of cold storage of control (unwaxed) and waxed fruit, respectively. The “excellent” flavor at harvest was associated with high sweetness, moderate acidity, high typical mandarin aroma and minimum off flavors. In contrast, the “fair” flavor detected after prolonged storage of waxed fruit was characterized by having lower acidity levels, less mandarin aroma and accumulation of off-flavors. Aroma profiling analysis conducted by GC-MS revealed that the contents of four aroma volatiles decreased by at least 2.5-fold during postharvest storage whereas levels of 16 aroma volatiles increased by at least 2.5-folds. Among the volatiles that decreased during postharvest storage, especially worth notice is the remarkable decrease in hexanal levels, whose aroma is characterized by contribution of a green fresh note. The volatiles that remarkably increased during storage belong to several metabolic pathways, including ethanol fermentation metabolism (acetaldehyde, ethanol, ethyl acetate), fatty acid catabolism (ethyl propanoate, ethyl octanoate, ethyl hexanoate, ethyl 2-hexanoate, ethyl 3-hydroxyhexanoate), amino acid catabolism (ethyl 2-methylpropanoate, ethyl 2-methylbutanoate, ethyl butanoate, ethyl 2-butenoate), and terpene biosynthetic pathways (eremophilene, α-thujene, sabinen).