An investigation into the prodution of reducing sugars from fruits and vegetables peels

Large quantities of fruit and vegetable waste are generated from agricultural processes worldwide. Fruit and vegetable waste has high levels of reducing sugar that can be fermented for production of fermentable products. The fact that the reducing sugar can be used in the production of fermentable products further increases its value. This work has focused on the potential of the peel use a zero-value waste as feedstock for production of fermentable products. The effects of grinding, alkaline pretreatment with heating, and enzymatic hydrolysis on production of reducing sugar were investigated while obtaining reducing sugar from apple, potato, melon, and orange peel. The peels were divided into two groups as ground and non-ground. Alkaline pretreatment with heating was applied at Bunsen burner for 0, 5, 7.5 and 10 minutes. The enzymatic process was performed in rotary shaker at pH 4.8 and 55 °C with cellulase enzyme as 1:50 (w/v) ratio for 3 hours. Also, the peel samples were investigated without enzymatic hydrolysis process. The amount of sugar present in each of these two groups was measured by DNS (3,5-Dinitrosalicylic acid) method. As a result of statistical analysis, grinding influenced on reducing sugar (p<0.05), while enzymatic hydrolysis and alkaline pretreatment with heating did not have any effect (p>0.05).