Hot water dip improves banana and mango fruit quality by Rita T. dela Cruz January-March 2003 Volume 5 no. 1 Source:Bar Digest The banana and the mango industries play an important role in boosting the country’s economic growth. These fruits top all other fruit crops in the country in terms of production area and demand by the domestic and foreign markets. However, problems in packaging and handling continue to hamper the development of these fruit industries. The key to good postharvest handling is careful harvesting. The quality of perishable foods is achieved from the moment they are picked or harvested. From this point, farmers should maintain postharvest conditions so that deterioration is minimized, and quality is at its best. Bananas and mangoes bruise easily and have short shelf lives. Under hot condition, fruit injuries are hard to avoid. Ripening starts at once after the picking then they become vulnerable to diseases. To extend the lives of these fruits, refrigeration becomes the only alternative. However, this results to chilling injuries such as discoloration and abnormal ripening due to the sudden change of temperature. At Leyte State University (LSU), a group of researchers developed a simple postharvest heat treatment called the Hot Water Dip or HWD to improve postharvest handling of mangoes and banana. Dr. Antonio Acedo Jr., Marilou Benitez, and Dr. Ma. Cherry Abit determined the effectiveness of this method in bananas and mangoes that have been exposed to normal, hot and cold conditions. This research won an AFMA Best R&D Paper Award in the 14th National Research Symposium (NRS) organized by the Bureau of Agricultural Research (BAR).
Employing the fruit hot bath
Previous studies show that employing postharvest treatment effectively lessens the responses of fruits to stressful conditions, controlled insects and diseases, and inhibited the ripening process. To determine the usefulness of HWD, the researchers used the latundan (Musa ABB) and saba (Musa BBB) bananas and carabao mango. They dipped the bananas and mangoes into water tanks at 47-49 oC and 51-53 oC, respectively, for 10 minutes. Meanwhile, chill treatment for the fruits were maintained at 8-10 oC for 8-10 days after the fruits were dipped into hot bath.
Healthier and better quality fruits
According to the researchers, HWD was able to reduce the incidence of disease, particularly finger rot and anthracnose infection. In terms of ripening, they noted no substantial effect on the fruits that were exposed to hot surroundings for five to six days. Under low temperature, HWD proved effective in minimizing fruit injuries. Saba bananas that were subjected to HWD turned ripe-soft two to three days later than the untreated bananas. They also had improved quality and had little or no diseases and infections. According to the researchers, HWD-treated fruits were anthracnose and finger rot free. During chill treatment the HWD-treated fruits also had less chilling injuries and only slight surface discolorations. For latundan, softening was slowed down significantly even if the bananas were exposed to high temperature. HWD also inhibited the degree of finger rot and anthracnose infection. The carabao mangoes that were immersed in hot water, had delayed ripening, 2-3 days after they were treated with HWD. Disease incidence was lower and the occurrence of anthracnose was very minimal. Also, the number of fruits infected by stem-end rot was lower compared to the untreated mangoes, and had less chill injuries.
HWD is economical
Through a cost-benefit analysis, researchers determined the economic practicability of resorting to HWD. For saba, researchers reported a gross profit of P0.54 per fruit and a net profit of P0.44 per fruit. This indicates that for every peso invested in HWD, there is an ensured net return of P4.4 (per fruit basis). Meanwhile, for fruits exposed under hyperthermal condition, farmers who used HWD would have a net profit of P0.40 and a return of investment of P4.0 for every fruit. For latundan, fruits exposed for a shorter period under hyperthermal conditions have a higher return of investment of P5.00 per fruit compared to those that were exposed longer with only P1.61 net return per fruit. HWD treatment for carabao mangoes is more profitable than in bananas. At ambient conditions, employing HWD gave a gross profit of P23.75 for every kilo of mangoes and a sure return of investment amounting to P14.83. (For more information about this study, please contact Drs. Antonio L. Acedo Jr., Marilou M. Benitez, and Ma. Cherry Abit at Leyte State University (LSU), Baybay, Leyte or you may call them through these numbers: (053) 335-2628 or 563-7113 or fax 3352752 or e-mail at acedo@philwebinc.com or junacedo@yahoo.com)