Effects of Fruit Load on Sugar/Acid Quality and Puffiness of Delayed-Harvest Citrus

Abstract

Delayed harvesting technology is believed to improve the citrus fruit flavor, but improper tree fruit load under delayed harvest might cause puffiness and reduce fruit quality. In order to find out an optimum tree fruit load level to obtain better flavor quality as well as reduce puffiness in delayed-harvest citrus under protected cultivation, experiments were conducted in the present study between 2019 and 2020 to determine the effect of different fruit loads and fruit-bearing per single branch on the soluble sugars and organic acids metabolism in the peel and flesh, the anatomical structure of the matured fruit peel, and fruit texture-related indexes. The results suggested significant negative correlations between leaf N level and flesh sucrose and glucose contents, and between branch P level and flesh citric acid contents; no significant correlation between NPK levels and flesh texture; relatively lower leaf N and branch P under relatively higher load can increase flesh sucrose and glucose accumulation and slow down citric acid degradation to the greater extent, thus optimizing the sugar/acid ratio of fruits during delayed harvest. The lignification of parenchyma cells closely around peel secretory cavities due to ascorbic acid deficiency might be the primary cause for puffiness under low-load treatments.

Metabolomic analyses provide insights into the preharvest rind disorder in Satsuma Owari Mandarin

“…PPO activity increased under stressful conditions, and this resulted in the formation of chemical barriers preventing further ROS from spreading. Polyphenol oxidases appear to have a role in plant immunity, and recent evidence suggests they may also be involved in other physiological processes ( Taranto et al., 2017 ) PPO is responsible for the oxidation of antioxidants, subsequently decreasing the antioxidant activity of cold-stored fruit and leading to the induction of chilling injury and loss of membrane integrity during cold storage ( Lee et al., 2012 ; Khefifi et al., 2020 ; Xu et al., 2021 ). The polyphenol oxidase enzyme found in fruits causes the enzymatic browning reaction.…”

Physical, Organoleptic, and Phytochemical Valuation of the Promising Greek Kiwifruit Genotype Arta Kiwifruit

“…"Arta Kiwifruit" produces large fruits without the need for chemical treatments, which is a significant advantage, as both the production costs remain low, and the overall kiwifruit cultivation becomes more sustainable (less use of pesticides and plant growth regulators), while at the same time extra fruit quality is achieved (FAO Codex Alimentarius, Standard for Kiwifruit, CXS 338-2020, adopted in 2020, https://www.fao.org/fao-who-codexalimentarius/committees/ committee/related-standards/jp/ accessed on 16 November 2023). In addition to fruit size, factors such as firmness, soluble sugars (TSS), organic acids, and dry matter accumulation play crucial roles in determining fruit quality and the ability to be stored effectively [22]. In the present study, the fruit dry matter did not differ between genotypes and was beyond the lower allowable limit for harvest (15%) (FAO Codex Alimentarius, Standard for Kiwifruit, CXS 338-2020, adopted in 2020, https://www.fao.…”