A 3-Year Sensory Fruit Quality Study in a Group of New Tangerine Hybrids

Florida tangerine (Citrus reticulata Blanco) production accounts for 40-50 % of the US production, and is the third largest of all citrus fruit, following oranges and grapefruits.  A number of tangerine selections from the University of Florida CREC breeding program were evaluated for fruit juice quality over three consecutive harvest seasons.  In the first year, 45 tangerine hybrids and 10 named commercial cultivars were sampled from November 2006 to March 2007.  Some samples were harvested multiple times over the season.   Fruit were washed, sanitized, and carefully juiced by hand to avoid incorporating peel oil volatiles into the samples.  Juice was frozen for later analysis of volatiles, titratable acidity (TA), soluble solid concentration (SSC), sugars and acids analyses as well as for sensory evaluation.  In the second year (2007-2008 harvesting season), 12 of the 45 tangerine hybrids evaluated previously were selected for re-evaluation, along with five named commercial cultivars as references, and eight new hybrids.  In the third year (2008-2009), many of the same hybrids and named cultivars as in the first and/or second year were re-evaluated.  A 15-member taste panel was trained for 24+ hours to describe aroma and flavor of tangerine juice, and a core of nine panelists participated during the full 3-year study.  Flavor profiles varied widely among all hybrids, and also within individual hybrids harvested at varying points within the maturity season, and between years. Hybrids with sweet orange in their background were specifically described with orange and floral aroma/flavor (‘Ortanique’ tangor), or sour with grapefruit-like or “fresh” aroma and flavor (‘Temple’ tangor, ‘Sanguinelli’ blood orange, ‘8-9’ × ‘Val4x’).  Other hybrids exhibited high sweetness and a characteristic “fruity-non-citrus” or “pumpkin” and “cooked” aroma/flavor (‘Fallglo’, crosses from ‘Robinson’× ‘Fairchild’, ‘Fallglo’ × ‘Faichild’, and one hybrid of unknown parentage).  Some selections had “sulfury”, “fatty” and “bitter” aroma and flavor, possibly due to delayed bitterness that is developed after juicing and in storage (‘Murcott LS’, ‘8-9’ × ‘Murcott’).  For some hybrids, flavor and aroma greatly varied with harvesting season and/or maturity at harvest (crosses from ‘8-9’ × ‘Murcott’ and ‘8-9’ × ‘Orlando’).  There was no typical “tangerine” aroma or flavor detected in the juice by panelists. As it is peel oil that gives a typical tangerine aroma to whole fruit, and hand juicing carefully excluded oil from the juice, this was not unexpected.