The effects of edible coatings based on sodium alginate with ʻBaozhuʼ pear chitinase on the quality of cherry tomatoes during refrigerated storage were evaluated. Cherry tomatoes inoculated with Fusarium oxysporum were coated and stored up to 21 days. All coatings with the chitinase significantly reduced F. oxysporum proliferation on cherry tomatoes during storage and extended the shelf life of cherry tomatoes effectively (p < .05). Results showed that alginate coatings with the chitinase could prevent weight loss, maintain firmness, and slow down the changes of titratable acidity and vitamin C (p < .05) in a dose‐dependent manner. However, no significant differences were observed between T3 (1% alginate/0.15% ʻBaozhuʼ pear chitinase/1% glycerin) and T4 (1% sodium alginate/0.3% ʻBaozhuʼ pear chitinase/1% glycerin) (p > .05). Overall, alginate coating with 0.15% ʻBaozhuʼ pear chitinase could be a promising method to maintain the quality of cherry tomatoes.

Antimicrobial active packing has demonstrated great potential in extending food shelf life. However, developing new intelligent and responsive antimicrobial strategies is still desirable. Here, a 2-hydroxy-4-methoxybenzaldehyde (HMB)-decorated chitosan film (HDCF) via surface Schiff-base coupling is designed. HDCF shows excellent storage stability and pH-responsive release, enabling a switch in antimicrobial mode from “defense” to “attack” under acid conditions. Before HMB release, HDCF exhibits broad spectrum antifungal adhesion capabilities against Penicillium citrinum, Penicillium chrysogenum and Aspergillus niger, and antibacterial adhesion capabilities against Staphylococcus aureus. Under acidic conditions, with HMB release, HDCF displays enhanced release-antifungal performance against A. niger, P. citrinum and Candida albicans and release-antibacterial performance against S. aureus. In addition, HDCF is effective in food preservation for cherry tomatoes and tomato juice and has good UV barrier properties. Therefore, this HDCF provides a new path for diversiform antimicrobial designs in the new generation of food packaging.

As global milk production continues to rise, the disposal of expired milk contributes to environmental pollution and valuable resource wastage. This study presents the development of a novel L-arabinose isomerase, designated BmAIase12, and its application in the enzymatic recycling of expired milk. BmAIase12 exhibited a specific activity of 10.7 U/mg and showed optimal performance at 50 °C and pH 7.0. Furthermore, it exhibited higher activity than most other L-arabinose isomerases. It converted D-galactose into D-tagatose with a high conversion ratio of 53.3% after 48 h at 50 °C. The conversion efficiency of expired milk to D-tagatose was recorded at 40.62%, resulting in a maximum tagatose yield of 1.625 g/L. This was accomplished through the incorporation of β-galactosidase (120 U/mL) and Saccharomyces cerevisiae (30 mg/mL) to hydrolyze lactose and metabolize glucose, followed by the addition of 3 U/mL of BmAIase12. Ultimately, following purification, the purity of tagatose was determined to be 98%, and the final yield was 29.8%. These results suggest that BmAIase12 may serve as a promising enzyme for D-tagatose production due to its high conversion yield.

A novel β-D-fructofuranosidase gene was identified via database mining from Leptothrix cholodnii. The gene was chemically synthesized and expressed in Escherichia coli, resulting in the production of a highly efficient enzyme known as LcFFase1s. The enzyme exhibited optimal activity at pH 6.5 and a temperature of 50 °C while maintaining stability at pH 5.5–8.0 and a temperature below 50 °C. Furthermore, LcFFase1s exhibited remarkable resistance to commercial proteases and various metal ions that could interfere with its activity. This study also revealed a new hydrolysis function of LcFFase1s, which could completely hydrolyze 2% raffinose and stachyose within 8 h and 24 h, respectively, effectively reducing the flatulence factor in legumes. This discovery expands the potential applications of LcFFase1s. Additionally, the incorporation of LcFFase1s significantly reduced the particle size of coagulated fermented-soymilk gel, resulting in a smoother texture while maintaining the gel hardness and viscosity formed during fermentation. This represents the first report of β-D-fructofuranosidase enhancing coagulated fermented-soymilk gel properties, highlighting promising possibilities for future applications of LcFFase1s. Overall, the exceptional enzymatic properties and unique functions of LcFFase1s render it a valuable tool for numerous applications.

A chemical gene synthesis strategy was developed in order to obtain β-D-fructofuranosidase, and a novel gene, AlFFase3, was characterized from Aspergillus luchuensis and expressed in Escherichia coli. The recombinant protein was purified, showing a molecular mass of 68.0 kDa on SDS-PAGE, and displaying a specific activity towards sucrose of up to 771.2 U mg⁻¹, indicating its exceptional enzymatic capacity. AlFFase3 exhibited stability between pH 5.5 and 7.5, with maximal activity at pH 6.5 and 40 °C. Impressively, AlFFase3, as a soluble protein, was resistant to digestion by various common proteases, including Flavourzyme, acidic protease, pepsin, neutral protease, Proteinase K, alkaline proteinase, and trypsin. AlFFase3 also demonstrated significant transfructosylation activity, with a yield of various fructooligosaccharides up to 67%, higher than almost all other reports. Furthermore, we demonstrated that the addition of AlFFase3 enhanced the growth of probiotics in yogurt, thereby increasing its nutritional value. AlFFase3 also improved the formation of yogurt gel, reducing the gel formation time and lowering the elasticity while increasing its viscosity, thereby improving the palatability of yogurt and reducing production costs.