Abstract:
The objectives of this study were to study: 1) the ripening index on physical and chemical quality and tannin content of banana (Musa spp. ABB Namwa) peel, 2) the effect of appropriate extraction conditions on tannin content in banana peel powder, and 3) the effect of sodium alginate (AG) coating combined and crude extract from banana peel on physicochemical quality of lime fruit after harvest.
All bananas were divided into 8 ripening stages. They were analyzed for their chemical composition and tannin content. An appropriate condition of extraction was examined. After that, all lime fruits were coated with alginate coating and crude extract from banana peel at 0:100, 10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, 80:20, 90:10, and 100:0 to expand the ripening time. Then, they were compared with uncoated fruit (controlled set). After coating and drying, lime fruits were placed at room temperature (12.3±2°C and 88±4 %RH) for 30 days.
The results showed that 1) the ripening stage was defined according to the index of peel color; stage 1 (dark green), 6 (yellow), and 8 (yellow and black spot in the peel). The banana peel powder of all stages was analyzed to find its chemical composition and tannin content. The results showed ash content, fat, fiber, and carbohydrate in the range of 11.40-13.77%, 7.37-10.53%, 35.39-42.37% and 23.88-33.21% respectively. It was also found that banana peel with L*, b* values decreased, while a* values increased. The banana peel powder at ripening stage 4 showed the highest tannin content, 2) in the extraction of distilled water, acetone and distilled water: acetone (1:1) for 2, 4, and 6 hours, it was found that distilled water: acetone extraction showed the highest tannin acid of 189.19 mg Tannin acid/g. In addition, there were non-significant (P>0.05) differences in the tannin content of all the extraction time, and 3) in the crude extract from banana peel and sodium alginate coating on physicochemical quality of lime fruit, it was found that coating lime fruit with alginate and crude extract from banana peel at a ratio of 50:50 could delay the could extend the shelf life of lemons up to 24 days, while the controlled uncoated lemons could only last 18 days. In addition, there was no disease occurrence on the lime skin cv. Pan in all treatments. Coating lime fruit had no effect on the juice content, the total soluble solids (TSS), titratable acidity (TA) and TSS:TA ratio. Coating lime fruit with the mixture of AG and crude extract from banana peel at a ratio of 50:50 yielded the highest remaining chlorophyll content on the last day of storage. The highest carotenoid content was found with the uncoated lime fruit at the end of storage. Therefore, the crude extract from banana peel can be potentially developed as a new trend for biological control agent from natural and bioactive substance.