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Cellulose nanocrystals (CNCs) with a high content of polar groups were prepared via the oxidation process by controlling the amount of mixed acid, incorporating additional additive of citric acid and vitamin C as active agents, and applying ultrasonic crosslinking. Subsequently, cellulose nanocrystal–silver (CNC–Ag) nanohybrid materials were synthesized via an oxidation hydrolysis reaction, which displayed good dispersibility and high interaction, leading to the hydrogen bonding between polar groups (-OH and -COOH) on the surface of CAC–Ag nanohybrids. The positive effects of hydrogen bonding on the surface of CAC–Ag nanohybrids were confirmed by the high carboxyl group content (2.69 mmol/g) and low contact angle (53.7°) tested. In addition, CAC–Ag nanohybrids showed significant antibacterial activity against both Gram-negative E. coli and Gram-positive S. aureus. These results showed that the high-performance CNC–Ag nanohybrids prepared in this study may be highly suitable as nano-fillers for polyester materials used in antibacterial food packaging.

In order to realize the resource utilization of the Pinus koraiensis pine cone, the polysaccharides were obtained by a traditional hot water extraction process, and the optimal extraction process was confirmed. The effects of a traditional hot water, alkali, and ultrasound assisted extraction on the yield and properties of polysaccharides were studied. The structure, monosaccharide composition, and content of polysaccharides obtained by different extraction methods were analyzed by means of Fourier infrared chromatography and liquid chromatography. Effects of polysaccharides extracted by different methods on the antimicrobial activity of Staphylococcus aureus and Escherichia coli were studied. The scavenging effect of DPPH free radicals were also examined. The optimum condition of the hot water extraction was identified as an extraction temperature of 100 °C, a ratio of material to water at 1:16 (w/v), an extraction time of 4 h, and a yield of polysaccharide at 10.2%. In comparison, the yield of the pine cone polysaccharide was improved significantly to 29.1% by using NaOH solution extraction method. The FTIR spectra of polysaccharides showed that the samples possessed the typical chemical structure of a polysaccharide. [ABSTRACT FROM AUTHOR]