Soluble peptidoglycan production from the waste peels of pineapple Ananas comosus (L.) Merr.

Introduction – The growing area of pineapple in Taiwan has reached 9797 hectares that annually produce 410,000 tons of pineapples and roughly contributed an amount of waste peels 119,583.5 tons. Whether the reclaim of the soluble polysaccharide fractions (SPF) from these waste peels are worth for green technology, we performed this study. Materials and methods – Cultivars TN-3 and TN-17 were used for analysis. Results and discussion – SPF differs in composition depending on the pineapple cultivars regarding the ash, carbohydrate, crude fiber, sugar, carotenoids and bromelain. At average, SPF of TN-3 and TN-17 consisted of carotenoids 4652 kg/Y and bromelian 2.117×10 ¹¹ units/Y. SPF was peptidoglycan in nature having average molecular weight below 500 kDa. The monosaccharide composition of SPF covered a spectrum of rhamnose, fucose, arabinose, xylose, ribose, fructose, mannose, galactose, glucose, and myo-inositol. The amino acid composition consists of mostly essential amino acids. SPF exhibited strong DPPH-, hydroxyl radical-, and superoxide anion radical-scavenging capability, but entirely ineffective as ferrous ion chelating agent. In cell mode, TN-3-2 behaved stronger cytotoxicity than TN-17-2. Based on the average amount of pineapple peels (119,583.5 tons), the reclaimable soluble peptidoglycans reached 6433.59 tons amounting up to 5.38% of the total waste peels. Conclusion – Using the improved novel green technology, it is possible to recover much of the valuable constituents present in the waste pineapple peels, in particular, the peptidoglycans that exhibit a diversity of biomedical significance.