Comparison of cellulose nanocrystals from pineapple residues and its preliminary application for Pickering emulsions

Pineapple, as a world-famous tropical fruit, is also prone to produce by-products rich in cellulose. In this study, different sections of pineapple, including pineapple core (PC), pineapple pulp (PPu), pineapple leaf (PL) and pineapple peel (PPe) were used for production of pineapple cellulose nanocrystals (PCNCs) by sulfuric acid hydrolysis. The crystallinity of PCNCs from PC, PPu, PL and PPe were 57.81%, 55.68%, 59.19% and 53.58%, respectively, and the thermal stability of PCNCs in order was PC > PL > PPe > PPu. The prepared PCNCs from PC, PPu, PL and PPe were needle like structure at the average aspect ratios of 14.2, 5.6, 5.5, and 14.8, respectively. Additionally, the differences in the structure and properties of PCNCs affected the stability of the prepared Pickering emulsions, which ranked as PPu > PPe > PL > PC. The Pickering emulsions stabilized by PCNCs prepared from PPu could be stored stably for more than 50 d. These results show the differences of PCNCs from four sections of pineapple, and provide isolated raw material selection for the further application of PCNCs.