Understanding Tree Fruit Consumer Acceptance C.H. Crisosto, G.M. Crisosto and D. Garner Department of Pomology University of California Davis California 95616 USA Keywords: peach, plum, nectarine, consumer, sensory, quality, SSC, TA, RSSC:RTA, organoleptic, perception Abstract The role of ripe soluble solids concentration (RSSC), and its relationship with ripe titratable acidity (RTA) in peach, plum, and nectarine consumer acceptance was studied as a part of our program to develop minimum quality indexes. Results of our adulterated peach juice sensory analysis indicated that liking is well related to the perception of sweetness, but titratable acidity (TA) plays an important role at low soluble solids concentration (SSC) levels (<10%). In cases where SSC and TA were low with a high sugar-to-acid ratio (SSC:TA), perception of sweetness was low. Thus, perception of fruit juice sweetness appears to be dependent on the absolute quality attribute levels. Similar responses were found on whole fruit using “in-store” consumer acceptance tests. We found three types of relationships between consumer acceptance and tree fruit cultivars. In one group of cultivars, the degree of liking and percentage consumer acceptance rapidly increased as RSSC increased, reaching 70-75% consumer acceptance. After that point, consumer acceptance reached a plateau and became insensitive to additional increases in RSSC. The saturation points ranged from 10-12% SSC according to cultivar. In another group of cultivars, the degree of liking and percentage consumer acceptance increased as RSSC increased, reaching very high levels (90-100% consumer acceptance). In a third group of cultivars, consumer acceptance was low (70%) and related to RTA within a given RSSC range. This data corroborates our trained panel results, and suggests that cultivars should be clustered in organoleptic groups prior to proposing a unique minimum quality index based on RSSC. INTRODUCTION New peach cultivars are being planted that have markedly different flavor qualities (low acid, high acid, high soluble solids concentration, highly aromatic, non-melting, etc.), and we are also reaching new markets with different consumer groups (Liverani et al., 2002; Crisosto, 2003). For this reason, we believe that it is important to understand the role of soluble solids concentration (SSC), titratable acidity (TA) and other flavor components in consumer acceptance in order to develop a quality index (Byrne, 2003; Crisosto, 2002, 2003). Early studies have associated high consumer acceptance with high SSC in peaches (Parker et al., 1991; INFOS-CTFL, 1999; Ravaglia et al., 1966). In France, with a large diversity of flavors available in the peach genotype (white/yellow flesh and low/high acidity) a minimum of 10% SSC for peaches with a low TA, and 11% SSC for peaches with a high TA is being evaluated as part of a quality standard (Hilaire, 2003). In Italy, with an industry that has a high proportion of yellow flesh cultivars, a minimum SSC of 10% for early season, 11% for mid season and 12% for late season cultivars was previously proposed (Testolini, 1995; Ventura et al., 2000). In this work we report preliminary results on the relationship between SSC and TA on consumer acceptance as a part of our full program to develop minimum quality indexes for stone fruit. 865 Proc. 5 th Int. Postharvest Symp. Eds. F. Mencarelli and P. Tonutti Acta Hort. 682, ISHS 2005