Foliar application of salicylic acid and calcium chloride delays the loss of chlorophyll and preserves the quality of broccoli during storage

Abstract

Consumer awareness of broccoli's unusual color, rich flavor, and concentration of desired phytochemicals has led to a steady increase in consumption in recent years. However, its short shelf‐life, which is linked with quick discoloration and degeneration after harvest, limits industrial production and marketing. The effect of pre‐harvest salicylic acid (SA) and calcium chloride (Ca) and their combination on the post‐harvest quality of broccoli during storage (5 ± 1°C) was explored in this study. The foliar spray treatments reduced weight loss of broccoli head during storage. At the end of storage, Ca (2%) alone and in combination with SA (0.01%) significantly maintained the chlorophyll concentration rather than control. The total phenols, flavonoid, and antioxidant capacity of the Ca (2%) + SA (0.01%) treated samples was significantly greater than the control. SA (0.01%) alone or in conjunction with Ca (2%), showed higher catalase (CAT) activity; however, Ca (1%), alone or in combination with SA (0.01%), showed higher peroxidase (POD) activity. Generally, the marketability of the treated broccoli was significantly greater than the control at the end of storage. Based on these findings, we believe Ca (2%) + SA (0.01%) improves the antioxidant system, delays chlorophyll degradation, and extends the shelf life of broccoli heads stored at 5 ± 1°C. It is proposed that the green color, marketability, and nutrient content of broccoli during postharvest handling and storage can be retained longer by foliar application of this treatment. Practical applications Broccoli (Brassica oleracea L. Italaia) is a widely‐consumed floral green vegetable due to its high content of nutrients and bioactive compounds. However, after harvest, florets rapidly senesce and suffer from yellowing which affects the quality of broccoli. The senescence of post‐harvest broccoli is characterized by fresh weight loss, chlorophyll degradation, and a significant reduction in nutritional content. Therefore, preventing the decline in the quality of harvested broccoli is essential to maintain its economic and nutritional value. The results of this study showed that pre‐harvest foliar application of Ca (2%) + SA (0.01%) with delayed weight loss, chlorophyll degradation, preservation of antioxidant compounds, and increased enzyme activity has a positive effect in maintaining broccoli heads quality during cold storage.

Exogenous citric acid, salicylic acid, and putrescine treatments preserve the postharvest quality and physicochemical properties of broccoli (Brassica oleracea L. var. italica) during cold storage

“…In the study by Alali et al (2023), it was observed that citric acid has the ability to close stomata, decrease transpiration rates, and mitigate weight loss in fruits and vegetables. Similarly, research conducted by Eleni and Theodoros (2011), Babu et al (2014) and Rastegar et al (2022) highlighted the anti-aging properties of CA, SA, and PUT, which also proved beneficial in reducing weight loss in vegetables by scavenging reactive oxygen species and preserving membrane integrity. Mustafa et al (2018a) reported that SA treatment is important for the degree of inhibition of the metabolic activity of the fruit and that 1 mM SA treatment delayed weight loss in mangosteen after 14 days of storage.…”

“…( 2014 ) and Rastegar et al. ( 2022 ) highlighted the anti‐aging properties of CA, SA, and PUT, which also proved beneficial in reducing weight loss in vegetables by scavenging reactive oxygen species and preserving membrane integrity. Mustafa et al.…”

“…Consequently, PPO comes into contact with phenolic compounds, leading to their oxidation. The primary reason for the higher retention of phenolic and flavonoid levels in response to CA, SA, and PUT treatments is the delayed senescence and reduced PPO activity (Alali et al., 2023 ; Rastegar et al., 2022 ; Razzaq et al., 2013 ). However, more investigation is needed to illuminate these biochemical processes in different broccoli cultivars.…”

“…By treating vegetables with some low‐dose chemical solutions postharvest, quality can be maintained and an increase in storage time can be achieved. However, the activities of these compounds vary depending on many factors, such as species, variety, environmental conditions, plant development period, application method, duration, and concentration (Alali et al., 2023 ; Rastegar et al., 2022 ; Razzaq et al., 2013 ). Putrescine (PUT), one of the substances used to maintain or improve postharvest quality in products, is a low‐molecular‐weight organic compound found in almost all living organisms (Khosroshahi et al., 2007 ).…”

Effect of Exogenous Calcium on the Heat Tolerance in Rosa hybrida ‘Carolla’

“…Indicators of the heat stress response include photosynthetic responses, antioxidant enzyme activities, cell membrane integrity [19], and the content of osmotic substances. It has been shown that exogenous Ca 2+ increased the heat tolerance of Arabidopsis [20] and Rhododendron [21], which might be associated with altering carbohydrate metabolism [22], delays the loss of chlorophyll [23], higher antioxidant enzyme activities [24], and decreased electrolyte leakage [25]. However, excessive Ca 2+ concentration might be cytotoxic [24], and the optimal concentration of Ca 2+ needs further experiments.…”