Post-harvest heat treatment of bananas - Effect on shelf life and quality

Heat treatment is a potential physical treatment to eradicate or delay development of pathogens and therefore prolongs the shelf life of fruits. A study was undertaken to examine the effect of heat treatment on quality and shelf-life of bananas. A water heating chamber (20 kg/batch) with temperature controller was developed for this purpose. Banana (cv. Cavendish) bunches were treated at 40 and 45 degrees C temperature for different durations (30, 45 and 60 min). Microbial analysis just after heat treatment revealed that it is essential to heat the banana at 45 degrees C for at least 45 minutes to reduce the fungal count in banana to an acceptable level. Heat treatment resulted in slight decrease in firmness of raw bananas. However, the rate of decrease in firmness during ripening and storage was more pronounced in case of control sample, indicating quick softening of control samples due to ripening. The firmness value decreased from an Initial value of 1.37 kgf to 0.26 kgf i. e. almost by 81 % after 7 days, whereas the same for heat treated samples ranged between 26-69 %. The Higher the temperature and duration of heat treatment, the less was the rate of ripening. Heat treatment also increased the lightness value of the banana peel. The yellowness index of treated bananas increased slowly compared to control samples. Heat treatment at 45 degrees C for 60 min was found to delay the ripening process and hence increase the shelf-life of bananas by 5 days.