ABSTRACT
Zucchini squashes are cold-sensitive and vulnerable to chilling injury (CI) resulting from reactive oxygen species (ROS) and hot water (HW) immersing effectively reduce CI symptoms during cold storage. However, mechanism involved in reduced ROS due to HW treatment has not been characterized well. In this study, tender green zucchini fruit were treated with HW for 15 min at 45 ± 1 °C and stored for 15 d at 4 ± 1 °C and above 90 % relative humidity. Results showed substantial reduction in CI index, electrolyte leakage, malonaldehyde (MDA) contents and ROS accumulation along with increased activity of ROS-scavenging enzymes due to HW treatment. To gain insight into the molecular mechanism involved in antioxidant defense system, transcriptomic analysis revealed that heat shock factors (HSF) accumulated due to HW treatment regulated the ROS pathway during cold stress. CpHSFA4a was one of the highly expressed transcription factors (TF) due to HW treatment that regulated the transcription of ROS enzymes related genes. CpHSFA4a bind actively with heat shock element (HSE) in promoter regions of CpSOD, CpCAT, CpAPX1, CpAPX2, and CpAPX3, activated and increased the expression of these genes. In conclusion, HW treatment alleviated the CI by maintaining ROS homeostasis through CpHSFA4a mediated ROS pathway in zucchini squashes during cold storage.
Subject(s)
Antioxidants , Fruit , Plant Proteins , Reactive Oxygen Species , Antioxidants/metabolism , Fruit/metabolism , Fruit/genetics , Reactive Oxygen Species/metabolism , Plant Proteins/metabolism , Plant Proteins/genetics , Cold Temperature , Water/metabolism , Gene Expression Regulation, Plant , Cucurbita/genetics , Cucurbita/metabolism , Hot Temperature , Food Storage , Heat Shock Transcription Factors/metabolism , Heat Shock Transcription Factors/geneticsABSTRACT
The effect of cutting styles (slice, pie, and shred) on the quality characteristics and antioxidant activity of purple and yellow flesh sweet potato cultivars during six days of storage at 4 °C was investigated. The results indicated that the sliced and pie samples showed no significant difference (p > 0.05) on the firmness, weight loss, and vitamin C content compared with the whole sweet potato in both cultivars during storage. The pie sample exhibited the highest wound-induced phenolic, flavonoid, and carotenoid accumulation and DPPH radical scavenging activity among the cuts in both cultivars. Moreover, the shredded sample showed significantly (p < 0.05) higher polyphenol oxidase (PPO) activity but lower total phenolic and flavonoid content and the lowest antioxidant activity among the samples. Thus, the finding of this study revealed that pie-cut processing has potential in improving the quality and increasing the antioxidant activity of fresh-cut purple and yellow flesh sweet potato cultivars while shredding accelerated the quality deterioration of both sweet potato cultivars.
