Postharvest application of antibrowning chemicals modulates oxidative stress and delays pericarp browning of controlled atmosphere stored litchi fruit

Abstract

Litchi fruit were treated with methionine [(0.25%) MN] and cysteine [(025%) CN] alone or in combination, and kept under 1% O2 + 5% CO2 controlled atmosphere (CA) at 5 ± 1ºC for 28 days. Among different treatments, CN was most effective to inhibit browning, than MN and CN + MN under CA conditions. Application of 0.25% CN significantly delayed browning index, reduced disease incidence, weight loss, malondialdehyde (MDA) contents, electrolyte leakage, hydrogen peroxide (H2O2), superoxide anion (O2–•) and polyphenol oxidase (PPO) and peroxidase (POD) activities with higher contents of total anthocyanins under CA‐storage. In addition, 0.25% CN treatment showed higher contents of ascorbic acid, total phenolics (TPC), and 2,2–diphenyl–1–picrylhydrazyl–radical scavenging capacity and activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) enzymes having maintained quality attributes. Therefore, 0.25% CN pre‐treatment could be considered a promising way for managing browning, and conserving litchi fruit quality under CA‐storage. Practical applications Litchi fruit are highly perishable due to rapid pericarp browning having limited postharvest market potential. The browning takes place due to enzymatic reactions and phenolic oxidation. However, it can be delayed by exogenous antibrowning treatments and suitable storage environment. The delayed incidence of pericarp browning may help to maintain its quality with extended storage potential suitable for domestic and international markets. So, the outcomes of the current work may help to maintain overall quality and to extend its storage potential that would be helpful in extending its market life with maintained visual quality at domestic and international destinations.

Analysis of metabolomics associated with quality differences between room‐temperature‐ and low‐temperature‐stored litchi pulps

“…Water loss (Jiang & Fu, 1999), pathogen infection (Wu et al, 2017), enzymatic catalysis by PPO (Sun et al, 2008), POD (Jiang, Duan, Joyce, Zhang, & Li, 2004) and laccase (Fang et al, 2015) have been identified as the main factors inducing pericarp browning. Treatment with chemicals containing antioxidants (Ali, Khan, Malik, Nawaz, & Shahid, 2019) and acids (Shah, Khan, & Ali, 2017;Zheng & Tian, 2006), heat water and steam (Kessy, Hu, Zhao, & Zhou, 2016;Olesen, Nacey, Wiltshire, & O'Brien, 2004), coating treatment (Hojo, Durigan, & Hojo, 2011), lowtemperature storage (Khan, Ahmad, Malik, & Amjad, 2012), and controlled atmosphere storage (Ali, Khan, Malik, & Shahid, 2016) effectively retard pericarp browning. In addition to pericarp browning, pulp deterioration decreases the quality of litchi fruits after harvest.…”

Postharvest application of L‐cysteine to prevent enzymatic browning of “Stanley” plum fruit during cold storage

“…In apple juice, L-cysteine could prevent brown pigment formation by reacting with the quinone intermediates to form stable colorless compounds (Iyidogan & Bayındırlı, 2004). It has been shown that postharvest treatment of litchi fruit with 0.25% L-cysteine for 5 min was effective in reducing disease incidence and weight loss, maintaining membrane integrity, and enhancing antioxidant capacity, total anthocyanins and total phenolic contents during cold storage (Ali, Khan, & Malik, 2016a), and controlled atmosphere storage (Ali, Khan, Malik, Nawaz, & Shahid, 2019). Also, L-cysteine alleviated the activities of POD and PPO enzymes, which lead to reduced pericarp browning index (Ali et al, 2016a(Ali et al, , 2019.…”

“…It has been shown that postharvest treatment of litchi fruit with 0.25% L-cysteine for 5 min was effective in reducing disease incidence and weight loss, maintaining membrane integrity, and enhancing antioxidant capacity, total anthocyanins and total phenolic contents during cold storage (Ali, Khan, & Malik, 2016a), and controlled atmosphere storage (Ali, Khan, Malik, Nawaz, & Shahid, 2019). Also, L-cysteine alleviated the activities of POD and PPO enzymes, which lead to reduced pericarp browning index (Ali et al, 2016a(Ali et al, , 2019. Moreover, postharvest treatment of L-cysteine hydrochloride delayed senescence, maintained higher reducing state and nutritional quality, and enhanced antioxidant activity of longan fruit during storage at 25°C for 8 days (Li et al, 2018).…”

Selection and validation of reference genes for RT-qPCR analysis in Litchi chinensis Sonn. pericarp

“…Several mitigation methods have been developed, such as SO2 fumigation [20], controlled atmosphere treatments [41], radiation in combination with low temperature storage [28], and dip treatments [1,22,23]. However, a long-term and effective method remains lacking.…”