Postharvest quality management of avocado (persea ameicana mill ) C V.Arka Supreme

Abstract

Avocado (Persea americana Mill) is a subtropical climacteric fruit originating from south-central Mexico and Guatemala that has gained global popularity owing to its rich nutritional composition. The fruit is valued for its high energy content, healthy monounsaturated fats that support heart health and is a good source of protein, potassium, and various vitamins. Despite its value, avocados are highly perishable due to their climacteric nature, characterised by a surge in ethylene production immediately after harvest, leading to rapid ripening and spoilage, within 5-6 days of storage, resulting in significant economic losses. The present study, entitled ‘Postharvest quality management of avocado (Persea americana Mill) cv. Arka Supreme’ was carried out at the Department of Postharvest Management, College of Agriculture, Vellanikkara, during 2023-2025 to standardise the postharvest treatments for delayed ripening and shelf life extension in avocado by the application of ethylene inhibitors and maintenance of optimum storage temperatures. The first experiment evaluated the efficacy of various ethylene inhibitors, including Salicylic acid (SA), Sodium nitroprusside (SNP), and 1- Methylcyclopropene (1-MCP) at different concentrations. The control fruits were spoiled and discarded after 6 days. SA and SNP treatments extended shelf life to 12 days, while 1-MCP treatments were superior, extending the shelf life to 15 days. Although statistical comparisons were made up to the 12th day (other treatments became unmarketable) fruits treated with 500 ppb 1-MCP remained marketable up to 15 days with highest quality attributes like lowest respiration rate (395.99 mg CO2 kg-1 h-1), ethylene production rate (88.95 μL kg-1 h-1), and physiological loss in weight (9.64 %) while maintaining the highest fruit firmness (1.86 kg cm-2), titratable acidity (0.2 %), total sugars (1.13 %), and moisture content (75.37 %) with the slowest increase in total soluble solids (7.15 °Brix) and oil content (9.91 %). Treated fruits also exhibited the highest retention of total phenolic content (75.51 mg 100 g-1), total flavonoids (32.87 mg 100 g-1), antioxidant activity (IC50 value 4.08), and peroxidase (POD) activity (1.9 U mL-1) with the lowest polyphenol oxidase (PPO) activity (3.16 U mL-1). The highest total score (60.9) in sensory evaluation also confirms 500 ppb 1-MCP as the most effective treatment. In the second experiment, the best treatment from the first experiment (500 ppb 1-MCP) was utilised to assess the effect of storage temperature on the quality and shelf life of avocado. The fruits stored under ambient temperature (30 ± 2 ℃) were discarded due to spoilage by the second week itself. Refrigerated storage (4-7 ℃) extended shelf life to 21 days, but caused severe chilling injury, negatively impacting quality. Cold storage (10 ± 2 ℃) was found to be the most effective in extending shelf life up to 37 days, retaining quality attributes like the lowest respiration rate (292.93 mg CO2 kg-1 h-1), ethylene production rate (27.25 μL kg-1 h-1), physiological loss in weight (7.57 %) and highest fruit firmness (1.98 kg cm-2). Total soluble solids (7.1 °Brix) and oil content (9.14 %) increased slowly, reaching peak values only by the 5th week. The treatment was also superior in retaining quality, with the highest titratable acidity (0.29 %), total sugars (1.21 %), moisture content (76.38 %), total phenolic content (78.52 mg 100 g-1), and total flavonoids (34.28 mg 100 g-1). It also maintained the highest antioxidant activity (IC50 value 4.09), peroxidase (POD) activity (1.97 U mL-1) and the lowest polyphenol oxidase (PPO) activity (3.09 U mL-1) along with the highest organoleptic score of 58.0 by the end of the 5th week. Pearson’s correlation analysis revealed strong relationships between ethylene production and other quality attributes of avocado. Ethylene evolution showed positive correlations with oil content, respiration rate, total soluble solids, and antioxidant activity, and negative correlations with firmness, titratable acidity, sugars, flavonoids, and moisture, indicating its key role in fruit ripening dynamics. The present study demonstrated that the combination of 1-MCP (500 ppb) and cold storage (10 ± 2 ℃) preserved the fruit’s physiological and biochemical quality by delaying the climacteric surge, successfully extending its shelf life from 6 days to 37 days. This research offers an effective strategy to mitigate postharvest losses and thereby promote a more stable and sustainable avocado supply chain.