2017 ASHS Annual Conference

Peaches grown in the Southeast are valued for their acidic, sweet flavor. A complex mixture of various sugars and acids at different ratios play a key role in determining these unique peach flavor attributes. To understand the flavor profile of fresh market peaches, individual sugar and acid components were investigated in 14 commonly grown cultivars from the southeastern U.S. over three seasons (2013-2015), and in 43 selections and cultivars from the Clemson University peach germplasm collection over two seasons (2014-2015). Fruits were harvested at the commercially ripe stage as determined by flesh firmness and by the chlorophyll content (IAD index). A composite flesh sample from 5 fruits for each genotype was analyzed using HPLC to quantify four sugars: sucrose, fructose, glucose and sugar alcohol sorbitol, and five acids: malic, citric, quinic, shikimic, and fumaric, commonly found in peach. Total sugar accumulation (sucrose, fructose, glucose and sorbitol) was highly influenced by cultivar, ripening season and environment. However, individual sugars (sucrose, fructose, glucose) were accumulated in similar levels in fruit of peach cultivars for all ripening groups except for sugar alcohol sorbitol. The significantly highest accumulation of sorbitol was detected in late ripening cultivars (August 1-15). The predominant sugar was sucrose, while the major acids were malic and citric acid. Only slight differences were observed in the individual sugar/acid ratios among the 14 commercially significant cultivars. Significant differences were discovered within the more genetically diverse breeding germplasm. These selections provide an opportunity to introduce a more diverse set of individual sugar and acid profiles within breeding programs through selective crossing, which could eventually lead to new flavor profiles for the peach market.