Phenolic profile associated with chilling tolerance induced by the application of a hot water treatment in bell pepper fruit

Hot water treatment (HT) has proved to alleviate chilling injury (CI) in bell pepper and other Solanaceae species, this has been associated with the presence of metabolites such as sugars and polyamines, which protect the plasmatic membrane. However, it is unknown if the phenolic compounds in bell pepper play a role in the CI tolerance induced by the application of a HT. The aim of this study was to identify the specific phenolics associated with induced CI tolerance in bell pepper by HT (53 degrees C, 1 to 3 min). Fruit treated for 1 min (HT-1 min) exhibited CI tolerance (the lowest symptom development, electrolyte leakage, and vitamin C loss) and was the chosen treatment for further experiments. The phenolic composition was affected by HT-1 min and CI. Phenolics presented a strong correlation with the antioxidant activity. In fruit with CI tolerance, the concentration of seven compounds was increased, being quercetin-O-rhamnoside-O-hexoside and chlorogenic acid the most remarkable. Quercetin-3-O-rhamnoside was accumulated only in fruit with induced tolerance, meanwhile orientin was particularly sensitive to heat and cold exposure. Thus, HT-1 min (53 degrees C, 1 min) is a useful technology to induce CI tolerance in bell pepper and such tolerance is associated with the phenolic composition that may reduce the prevalence of oxidative stress during the storage under CI conditions. Practical Application Phenolics induced by CI and HT may be useful to detect early stages of heat and chilling injuries in bell pepper and prevent the negative effect of such stresses even before its harvest and during commercial storage. Additionally, the phenolics associated with CI tolerance may be used as markers in breeding programs to create new chilling resistant cultivars.