2011 Annual Report 1a.Objectives (from AD-416) 1) Assess sensory quality and aroma profile compositions of commercial and new mandarin varieties currently under investigation in breeding programs in the U.S. and Israel. 2) Characterize the effects of postharvest handling procedures (degreening and coating with waxes) and storage conditions (temperature and duration) on sensory quality and aroma profile compositions of various mandarin cultivars. 3) Identify key aroma compounds involved in determining unique mandarin flavor and off-flavors by gas chromatography-olfactometry (GC-O) coupled with a human nose smelling device. 1b.Approach (from AD-416) Experiments will be conducted with two commercial tangerine cultivars, Fallglo and Murcott, as well as selected new tangerines in the ARS breeding program close to release. Optimum harvest maturity will be determined for new varieties. Degreening and wax treatments will be applied on commercial varieties. Sensory evaluation and volatile analysis will be performed under objectives 1 and 2. Sensory evaluation, GC and GC-olfactometry will be performed under objective 3. 3.Progress Report This project is related to Objective 1 of this in-house project: Evaluate the effect of genetics on microbial stability and composition of flavor and healthful compounds – sugars, acids, volatiles, carotenoids, total phenolics, pectin and fiber – in citrus, tomato, and subtropical-bred small fruit breeding lines. Mandarin hybrids and commercial cultivars were harvested at 3 to 4 week intervals and subjected to descriptive sensory evaluation. A taste panel could perceive the increase in sweetness and juiciness and decrease in sourness and bitterness with maturity. The possibility of processing two complex citrus hybrids comprising of 1/2 sweet orange, 3/8 mandarin and 1/8 grapefruit for a unique citrus juice beverage was investigated. One of the two hybrids tended to develop bitterness after a week in storage or if frozen, while the other hybrid had outstanding quality.