Structural, physicochemical and functional properties of industrial residues of pineapple (Ananas comosus)

Pineapple residues can account for 50% of waste weight.The aim of this research was to study the structural, physicochemical and functional properties of the industrial residues of pineapple to obtain information for recommending their use as dietary fibre. The pineapple residues had a high concentration of cellulose and a low crystallinity index (21.47-30.4%; 14.90-25.86 cellulose I and II, respectively). Scanning electron microscopy (SEM) revealed helical tracheids (HT) and sclerenchymatic fibres (SF) in the shell and helical tracheids in the leaf bracts and various 'individual' fibres with a semi-helical cord (SHC) shape in the core. Additionally, the pineapple residues exhibited low concentrations of lignin, which is an advantage when they are subjected to chemical or enzymatic hydrolysis. Therefore, a new type of product based on these residues could be considered helpful for promoting the nutritional value of foods and extending the utilisation of residues.