Application of Anantmul (Hemidesmus indicus) root extract improves postharvest shelf-life of dessert banana

Abstract

Banana (Musa sp.), a climacteric fruit ripens rapidly after harvesting resulting in a very short postharvest shelf-life. Exogenous salicylic acid (SA) treatment is one of the widely adopted practices to improve postharvest shelf-life of banana. The rationale behind such chemical treatment is to slow down climacteric ripening that involves ethylene production along with boosting of defence responses against fruit pathogens. In this study, we assessed the possibility of replacing chemically synthesized SA with a plant-based natural product (PBNP), 2-hydroxy-4-methoxy benzaldehyde (MBALD), a substituted analogue to SA, sourced from roots of Hemidesmus indicus. Dessert banana fingers (cv. Kanthali and cv. Malbhog) harvested after 80 days of post-anthesis were subjected to postharvest treatment by dipping in treatment solution for 8 h. Four different experimental sets namely, water (C), 2 mM MBALD (T1), 1 mM SA (T2) and 200 g/L H. indicus root extract (T3) were employed. After treatment, the fingers were stored at 25 ± 2 °C with 90 ± 2% relative humidity (RH) for 10 days but examined at an interval of 24 h. Ripening-related physicochemical and physiological changes decreased in T1, T2 and T3 in comparison with control (C). Reduced in vitro activities of major cell wall degrading enzymes were observed in all the treatments (T1, T2, T3) when compared with control (C). Expression of candidate genes of ethylene biosynthesis namely, ACC synthase (ACS), ACC oxidase (ACO), along with chitinase (CHT) and pathogen-related protein-1 (PR1) were found to be suppressed in all the treatments with T3 to be the best performer. Furthermore, in vitro culture of latently infected fruit mycoflora when grown in the presence of T3 showed a substantial reduction in growth rate. Such observation makes T3 a promising alternative to choose in the postharvest management of banana.