Assessing the Impact of Elevated Day and Night Temperatures on Flesh Red Coloration and Diminished Quality in Peaches

Abstract

In South Korea, the prevalence of red coloration in peach flesh has been widely documented in recent years owing to elevated temperatures triggered by climate change. This study implemented soil–fruit–daylight–system (SFDS) artificial chambers that maintained four distinct day and night temperature categories to provide an overview of the effects of high temperatures on flesh discoloration and reduced fruit quality in ‘Daewol’ peaches. The day and night temperatures in each chamber were maintained as 1; 20°C/10°C; 2; 25°C/15°C; 3; 30°C/20°C; and 4; 35°C/25°C, while all other external factors remained constant. Changes in flesh color and the physicochemical quality characteristics related to flesh were assessed under these conditions over two consecutive years, 2022 and 2023. The significantly lowest fruit weight was observed in the 30°C/20°C and 35°C/25°C chambers, where tropical night phenomena were demonstrated. A remarkably higher soluble solids content was reported from the 35°C/25°C chamber, with firmness however not showing a significant difference among the chambers. Peach flesh displayed excessive red/brown coloration in the 30°C/20°C and 35°C/25°C chambers, exhibiting higher a* values, lower hue values, and color development index (CDI) values beyond 0.5 ± 0.01, where 0.5 signifies maximum yellowness. Furthermore, the markedly highest reddish pulp index was observed in the chambers with temperatures set to 30°C/20°C and 35°C/25°C. These findings emphasize that reddish pulp disorder intensifies with elevated temperatures as a result of climate change. Hence, it is crucial to prioritize and address this issue to maintain a steady peach production process and improve peach quality levels ultimately to meet the demand for peach fruit. This requires the prompt adoption of strategies such as appropriate irrigation, shading methods to protect the fruits from intense sunlight, and choosing peach varieties that can withstand high temperatures.