Comparative study for a potential usage of underutilized or wasted fruits for sanitizer production

Abstract

The Covid-19 pandemic situation was a recent issue that drew global concern about the use of hand sanitizer to control the spread of pathogens through personal contact. This study aimed at bioethanol production using abundant wasted fruits or underutilized fruits as a cheaper raw material source. Six species of overripe fruits: banana, mango, papaya, star fruit, sapodilla, and jackfruit were tested at three different fermentation periods. Pulps were extracted from surface sterilized fruits using KMnO4 (5% w/w) and fermentation was facilitated by inoculating Saccharomyces cerevisiae as inoculum with a calculated amount of sucrose and urea. The pulps were analyzed for proximate composition (moisture, ash, fiber analysis) and physicochemical parameters (pH, brix, acidity) and the concentration of ethanol and methanol fermented pulps were measured in three-week intervals. The highest ethanol concentration was resulted by jack fruit at the ninth week (17.3±0.416%) followed by banana at the sixth and ninth weeks (16.4±0.586% and 16.27±0.902% respectively). Jack fruit and banana showed a significantly high ethanol production even at the third week (16.1±0.265% and 15.73±0.416 respectively). During fermentation, all the fermented samples contain high amount of methanol (>15%). Therefore, the methanol production was controlled by adjusting pH (2.5-3.0) using citric acid. pH adjusted samples have recorded ethanol 14.8±0.28%, methanol 6.7±0.14%, Brix 6.15±0.07 and pH 3.65±0.01, respectively. The steam distillation method was carried out to purify the alcohol from fermented samples. The highest mean ethanol concentration was observed in jackfruit (71.33%). The methanol percentage of the samples decreased with time and the final product consisted of a negligible amount of methanol (0.002%). The highest ethanol percentage was observed in fruits that had the highest brix values. Total plate count study after sanitizing hands with 75% ethanol produced by jackfruit revealed that the produced sanitizer can be successfully used to produce hand sanitizer