The commercial cellulose fibers and cellulose fibers extracted from rice and oat husks were analyzed by chemical composition, morphology, functional groups, crystallinity and thermal properties. The cellulose fibers from rice and oat husks were used to produce hydrogels with poly (vinyl alcohol). The fibers presented different structural, crystallinity, and thermal properties, depending on the cellulose source. The hydrogel from rice cellulose fibers had a network structure with a similar agglomeration sponge, with more homogeneous pores compared to the hydrogel from oat cellulose fibers. The hydrogels prepared from the cellulose extracted from rice and oat husks showed water absorption capacity of 141.6-392.1% and high opacity. The highest water absorption capacity and maximum stress the compression were presented by rice cellulose hydrogel at 25°C. These results show that the use of agro-industrial residues is promising for the biomaterial field, especially in the preparation of hydrogels.

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There is a worldwide demand for environment‐friendly, biodegradable materials. The objective of this study is to develop biocomposite films using native or phosphorylated wheat starch reinforced with cellulose nanocrystals (CNCs) from three different sources, rice, oat, and eucalyptus husks. The films are evaluated by their morphology, thermal properties, relative crystallinity (RC), water vapor permeability (WVP), and mechanical properties. The high RC of the CNCs increases the RC of biocomposite films. The films produced using native and phosphorylated starches present higher WVP than those incorporated within CNCs. The films without CNCs also present low solubility, remain intact after 24 h of immersion in water under agitation, and resist water absorption. The CNCs incorporation increases the tensile strength of the films. Biocomposite films produced using native starch and oat CNCs yield the highest tensile strength (5.07 ± 0.33 MPa), showing a remarkable increase of 91.3% when compared to the film obtained using native starch (2.65 ± 0.09 MPa). The biocomposite films produced in this study show satisfactory mechanical properties, such as high resistance and flexibility, thereby presenting great potential for application in food industry.

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