Nanocellulose-based nanocomposite hydrogels are promising materials in different fields of application such as medicine, food, and agriculture.

This study aimed to characterize nanocellulose extracted from cotton (Gossypium hirsutum) linters. The nanocellulose was subjected to electronic microscopy, thermal analysis, X-ray diffractometry, light scattering, and contact angle. The properties of the nanocellulose are considerably different from the linter. The acidic hydrolyses applied to extract the nanocrystals increased the crystallinity index and the hydrophilicity and decreased the thermal stability. On average, the nanocrystals were 177 nm long and 12 nm wide, with an aspect ratio of 19 when measured by microscopy. The light scattering results were coherent with the crystal dimensions. Cotton linter is a potential source of nanocellulose crystals, particularly to be used in the production of hydrophilic nanocomposites. Extraction of nanocellulose from raw cotton linter does not require pulping.

a b s t r a c tCombinations of fruit purees with polysaccharides have been explored to produce edible films and coatings. In this study, the combination between acerola puree and alginate was reinforced with cellulose whiskers (CW) or montmorillonite (MMT) to form nanocomposite edible films (casted on glass plates) and edible coatings (applied on acerola fruit surfaces). Three film/coating dispersions were formulated, based on unfilled alginate-acerola puree (AA), CW-reinforced alginate-acerola puree (CWAA), and MMT-reinforced alginate-acerola puree (MMTAA). Both nanofillers (CW and MMT) reduced water vapor permeability (WVP) of films. When applied to fresh acerolas, the coatings decreased fruit weight loss, decay incidence, and ripening rates. Ascorbic acid retention by the fruits were favored by the coatings, especially the nanocomposite ones. The MMTAA coating was the most effective in reducing weight loss of acerolas. Moreover, it was the coating which best maintained its red color and the visual acceptance of coated acerolas.

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