During this study, fresh mangoes were packed into multilayer coatings made from chitosan containing cinnamon essential oil microcapsules and alginate solutions that were alternately deposited on the mango surfaces by electrostatic interaction. We then compared the physical and chemical indexes to examine the changes in the mangoes during 14 d of storage. The results showed that the microcapsules prepared in the experiment were of uniform size, with the sustained release of essential oil exceeding 168 h. Compared with uncoated mangoes, the mangoes coated with the coatings could effectively inhibit the decrease of the titratable acid, soluble solids, and vitamin C contents; slow down the increase of the weight loss and pH; delay the appearance of mango respiration peaks; and preserve the firmness at storage conditions of 25 °C and 50% RH. Our findings revealed that mangoes without treatment showed losses in their edible and commercial value after 14 days in storage, and the mangoes coated with five layers still retained food and commercial value. Cross-sectional scanning electron microscopy images of the coatings showed that they had distinct layers and were of good uniformity and tight binding, and they also had good adhesion to the mango surface. These findings provide important insights into the use of coatings for the packaging of fruits during storage, which is essential for promoting the application of coatings for packaging preservation without big cost and expensive equipment.

Deep eutectic solvents (DESs) is a newly developed green solvent with low cost, easy preparation and regeneration. Because of its excellent solubility and swelling effect in lignocellulose, it has received widespread attention and recognition. In this study, choline-based deep eutectic solvents (DESs)—choline chloride-urea (CC-U), choline chloride-ethylene glycol (CC-EG), choline chloride-glycerol (CC-G), choline chloride-lactic acid (CC-LA), and choline chloride-oxalic acid (CC-OA)—were used to extract and separate bagasse. The effects of hydrogen bond donors on lignin separation and the fiber and lignin structure were investigated. All five DESs could dissolve lignin from bagasse; acidic DESs exhibited higher solubility than basic DESs. CC-OA effectively separated lignin and hemicellulose. CC-LA showed weaker lignin separation ability than CC-OA. CC-G, CC-EG, and CC-U were more inclined to selectively separate lignin than hemicellulose. The crystalline cellulose II structure was retained after DES pretreatment. Acidic DESs effectively improved the crystallinity of bagasse fiber; the crystallinities for CC-OA and CC-LA pretreatment were 62.26% and 61.65%, respectively. The lignin dissolved in DES was mainly syringyl lignin. The lignin dissolved in CC-U, CC-LA, and CC-OA contained a small amount of guaiacyl lignin.

This study investigated the effectiveness of cellulose nanocrystals derived from cassava residues as a reinforcement to starch films. Thermoplastic starch films are biodegradable to a certain extent, but the scope of their applications is limited due to their strong water absorption and poor mechanical properties. Therefore, we used abandoned cassava residues to prepare cellulose nanocrystals quickly and efficiently using a mechanochemical method. Their average diameter and length were 6.281 nm and 437.232 nm, respectively, with an aspect ratio of 70; this average size is smaller than that of CNCs obtained via acid hydrolysis. Cellulose nanocrystals were ester modified using soybean oil to improve their polarity and hydrophobicity. Thermoplastic starch-based composite films were prepared using the film casting method; the mechanical and wettability properties of these films were investigated, by controlling the concentration of modified cellulose nanocrystals in the films. Scanning electron microscopy results showed that M-CNCs were evenly distributed in the composite films; thermal stability analysis showed that composite films exhibited high thermal stability; Fourier transform infrared spectroscopy results showed that the structure of cellulose nanocrystals prepared using a mechanochemical method was stable; water contact angle measurements showed promising hydrophobic effects at a contact angle of 105.7°. Moreover, mechanical tests showed that the tensile strength of the composite film increased by 73%. Therefore, soybean-oil-modified cellulose nanocrystals were excellent reinforcing agents for thermoplastic starch films, effectively improving the overall performance of the films.

Nanocellulose was prepared by a mechanochemical method using cassava residue as a raw material and phosphoric acid as the auxiliary agent. The prepared nanocellulose was hydrophobically modified with stearic acid to improve its dispersibility. This modified nanocellulose was added to polylactic acid (PLA) film-forming liquids at concentrations of 0%, 0.5%, 1.0%, 1.5% and 2.0%, and the effect of modified nanocellulose on the mechanical properties of polylactic acid (PLA) films were investigated. When at least 0.5% modified nanocellulose is added, more active groups of modified nanocellulose are adsorbed onto the PLA molecular chain. Although the tensile strength of the film is only improved by 13.59%, the flexibility of the film decreases, and the elastic modulus decreases by 28.91%. When 1% modified nanocellulose is added, the modified nanocellulose and PLA are tangled together through molecular chains and they co-crystallize to form a stable network structure. The tensile strength of the nanocomposite films is enhanced by 40.03%, the elastic modulus is enhanced by 55.65%, and the flexibility of the film decreases.

In this study, an physico-chemical method and enzymatic improvement were used to extract cassava dietary fiber from cassava residue. α-amylase, glucoamylase, lipase, and protease were added to the physically comminuted cassava residue to remove starch, fat, and protein. Then, with the aid of ultrasound, dietary fiber was bleached with hydrogen peroxide to increase its whiteness. Finally, the cassava dietary fiber was treated with cellulase to increase the amount of soluble dietary fiber. The yield of dietary fiber was 75.63%, 37.55% of which was soluble dietary fiber. Water-holding capacity, water-swelling capacity, and oil-holding capacity of cassava dietary fiber were 4.020 g/g, 2.091 mL/g, and 2.891 g/g, respectively, which were 11.14%, 52.85%, and 9.55% higher than those of raw tapioca. Thus, the physical and chemical properties of the dietary fiber were improved.