2.1. Orange fiber
Orange (Citrus sinensis) juice extraction waste was provided by
the “Pure Juice” company, located in Porto Alegre (RS/Brazil). These
waste components consisted of the orange peel, pulp and seeds
that had been manually separated into two groups: peel, pulp
(flavedo and albedo) and seeds (F1); and peel (F2). The rawmaterial
was collected in a single week and stored at 18 C for further use.
The fiber samples were thawed at room temperature, manually
cut into pieces of approximately 1 cm2, andwashed and sanitized in
a sodium hypochlorite solution (150 mg/L) for 10 min. The samples
were dehydrated in a tray dryer at 60 C until the weight remained
constant, approximately 4 h. After cooling to room temperature
(25 C), the dried product was ground in a mill (Arbel, model
MCF55, Brazil). The milled fiber was separated using sieves for
particle size analysis (Bertel, Brazil); the separated particles were
smaller than 125 mm (mesh 115). The fiber was packed in a vacuum
sealer (Fastvac, model F200, Brazil) and stored in the dark at room
temperature (25 C).