Production of natural nano-gel from pineapple polysaccharides complexes for controlled release of bioactive compounds

Abstract

[Excerpt] Pineapple (Ananas cosmosus) is the third most important tropical fruit in world production, seventy percent of the pineapple produced in the world is consumed as fresh fruit. In the agro-food sector, several materials are eliminated as waste throughout production and processing chain. These residues (skins, seed and pulp remnants) contain high content of bioactive compounds, but in generally not directly available, and for that reason is necessary to extract and characterize the feasible bioactive compounds (do Espírito Santo et al., 2012). Therefore, the study of the wastes and by-products generated during pineapple production and post-harvest processing is relevant and interesting to valorise them and reduce their environmental impact. The development of vehicles using these residues that deliveries the compounds as well promotes the maintenance of bioactivity, has been widely study, but lacks the search of new structures that could be easily used in food industry. Therefore, the focus of this research work was to developed nanocarriers using pineapple residues to extract pineapple polysaccharides for delivery of bioactive compounds. Frozen pineapple wastes were submitted to a milling and pressing processes, creating a pineapple juice and a solid semi-dried extract. Characterization was made for both parts comprised proteins, sugars, fibers, lipids and polyphenol contents. The soluble fraction was fractionated by centrifuge filter tubes with cut-off of 50 kDa and after by cut-off of 3 kDa, and three fractions were obtained: above 50 kDa, between 50 and 3 kDa and below 3 kDa. The insoluble part was submitted to hot aqueous extraction. The supernatant and the pellet of this extraction were separated and studied separately. Pineapple polysaccharides were identified and quantified by HPLC method and phenol-sulphuric method, respectively. [...]