2017 ASHS Annual Conference

Peach trees [TropicBeauty (TB) and UFSharp (UFS)] received N fertilization rates of 0 (N0), 44 (N1), 89 (N2), 179 (N3), or 269 (N4) kg/ha since establishment in 2011. The objective of this project was to determine the effect of N on peach fruit flavor. Ripe fruit volatiles were analyzed in 2015 and 2016. A total of 35 volatiles were quantified for each N treatment, variety, and harvest season. Sensory evaluations were conducted in 2015 and 2016 using consumer taste panels. Panelists scored fruit using gLMS, hedonic, and GLMS scales. Attributes such as overall liking, texture, sweetness, sourness, and overall peach flavor intensity were scored by the panelists. Nitrogen treatments did not show significant volatile or flavor differences compared with the control. Volatiles were mainly affected by variety and season. ‘TropicBeauty’ had lower quantities of lactones than UFS. However, gamma decalactone was higher than the other lactones in both varieties regardless of N treatment. In addition, UFS in 2016 showed a significant decline in gamma-decalactone quantity compared with 2015. The abundance of the 35 volatiles was lower in 2016 than 2015 except for hexyl acetate, linalool, and cis-3 hexenyl acetate. Sensory results elucidated certain volatile data: treatments with lower gamma-decalactone and gamma-hexalactone were less liked by panelists. Contrary to the volatile data, panelists detected some subtle differences among N treatments. However, different results were obtained in the 2015 and 2016 seasons. In 2015, for TB, N1 fruit were scored lower (overall liking) and were significantly different than N4; no differences between N treatments and the control were perceived. On the contrary, in 2016 N0 was least liked by the panelists, but was significantly different from N3 only. Sweetness was also significant in both years for TB: fruit from N0 scored lower on sweetness, significant differences from N3 were observed in 2015 and, in 2016, N2, N3, and N4 were sweeter compared to N0. ‘UFSharp’ fruit from N3 had lower sourness in 2016, significantly different than N0, N2, and N4. There were no differences in overall liking for UFS in 2015. Conversely, overall peach flavor intensity was lower in fruit from the highest N rate, but it was significantly different only from N2, which had the highest score. In these two peach varieties, N fertilization rate did not greatly affect volatile synthesis. Nonetheless, our taste panel results showed that N had a positive effect on TB but not UFS taste and aroma.