Pre-storage temperature conditioning reduces cortex browning and cavity and alters organic, amino, and fatty acid metabolism in cold-stored ‘Chuhwangbae’ pears

Authors: LWIN, HNIN PHYU - Chung-Ang University; Leisso, Rachel; LEE, JINWOOK - Chung-Ang University

Submitted to: Scientia Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/8/2023
Publication Date: 3/20/2023
Citation: Lwin, H., Leisso, R.S., Lee, J. 2023. Pre-storage temperature conditioning reduces cortex browning and cavity and alters organic, amino, and fatty acid metabolism in cold-stored ‘Chuhwangbae’ pears. Scientia Horticulturae. 315. Article 111989. https://doi.org/10.1016/j.scienta.2023.111989.
DOI: https://doi.org/10.1016/j.scienta.2023.111989

Interpretive Summary: Asian pears are prone to chilling injury when cooled rapidly in storage postharvest. Four temperature conditioning treatments were evaluated to determine if a delay in cooling fruit to final storage temperature can reduce the incidence of postharvest disorders, specifically internal browning and cavity development. Of the treatments evaluated, a temperature conditioning period 1 week at 22 C prior to 0.5 C storage was optimal for reducing incidence of internal browning and cavities. Shrivel increases with temperature conditioning at 22 C beyond 1 week. Additional aspects of fruit quality (acidity, soluble solids), physiology (ethylene and CO2 production), and metabolism (targeted metabolic profiling) related to conditioning treatments and disorder incidence are discussed.

Technical Abstract: ‘Chuhwangbae’ pears are susceptible to internal disorders thought to be related to abiotic physiological chilling stress during cold storage. Pre-storage temperature conditioning (e.g. gradual or step-down of fruit temperatures) after harvest is highly recommended to control the development of postharvest storage disorders during cold storage. This study aimed to evaluate the effects of pre-storage temperature conditioning (holding fruit at ~22 °C) on ‘Chuhwangbae’ pear fruit quality including the incidence of physiological disorders, and to determine major metabolic responses related to these disorders during cold storage. Postharvest pre-storage temperature conditioning (1, 2, 3, or 4 weeks at 22 °C) reduced cortex lightness and flesh firmness, and increased fruit weight loss and shrivelling during cold storage. The incidence and severity of cortex browning and decay were reduced by pre-storage temperature conditioning. Pre-storage temperature conditioning reduced glucose, sorbitol, and fumaric acid contents in fruit evaluation following 3 months cold storage. Phenylalanine, isoleucine, and valine contents decreased with pre-storage temperature conditioning, but methionine, glutamine, and proline contents were higher in conditioned fruit. In addition, oleic acid content and the ratio of unsaturated fatty acid to saturated fatty acid were reduced by pre-storage temperature conditioning during cold storage. Results indicate that pre-storage temperature conditioning reduces incidence of cortex browning and cavity in part by altering cell wall metabolism during cold storage. Concurrently, pre-storage temperature conditioning reduces metabolites that are substrates for primary metabolism (glucose, sorbitol, and fumaric acid) and for volatile metabolism (isoleucine and valine), suggesting that other aspects of fruit quality may be negatively affected by pre-storage temperature conditioning.