Pineapple (Ananas comosus L. Merr.) peels as agricultural wastes represent around 35% of the whole fruit mass. By different
preparation methods, the pineapple peel fiber was analyzed and evaluated for its composition and functional properties, which would provide a clue to its physiological function. The pineapple peel contained an appreciable amount of insoluble fiber-rich fraction (FRF)
(41.8 - 48.0 g/100 g) including insoluble dietary fiber (IDF), alcohol-insoluble solids (AIS), and water-insoluble solids (WIS), which
primarily consisted of cellulose, pectic substances and hemicellulose. These fractions also contained notable proportions of lignin
(60.7 - 65.8 g/100 g). Compared with cellulose, these FRFs exhibited the greater water- and oil-holding capacities (7.94 - 12.3 mL/g and
5.84 - 8.64 g/g, respectively), swelling properties (10.6 - 18.4 mL/g), and cation-exchange capacities (102 - 120 mequiv/kg). The results
indicate that the physicochemical properties of various fibers are dependent on the preparation method and composition. Every insoluble
FRF studied possesses interesting characteristics, suggesting possible uses in the development of functional food ingredients for reduction of calories or dietary fiber enrichment.