In the present work, Pickering emulsions were fabricated using burdock RG-1-type pectic polysaccharides/zein composite particles as emulsifiers. The effects of polysaccharide concentration, pH, ionic strength, and oil phase volume fraction (φ) on the physicochemical properties of the Pickering emulsions were systematically analyzed. Besides, the efficacy of the emulsions for stabilizing and delivering curcumin were also elucidated. The results showed that the optimal conditions for the formation of Pickering emulsions were pectin concentration 10 mg/mL and pH 3–5. The emulsion was stable under NaCl concentration of 40–200 mmol/L and oil volume fraction of 0.17–0.75. Rheological results showed that low concentration of calcium ion effectively strengthened the interfacial structure of the emulsion containing curcumin, while when the concentration of calcium ion increased to 4 mmol/L, the emulsion gel shrank, reducing its viscoelasticity. The thermal stability and bioavailability of curcumin were significantly improved by high internal phase emulsion encapsulation. The bioavailability of curcumin encapsulated in the cross-linked emulsion with 1 or 2 mmol/L calcium ion was highest, more than 60%. This study is of positive significance to expand the application of RG-1-type pectic polysaccharides/zein composite nanoparticles in food delivery systems.

In order to investigate the effect of ultrasound-assisted fermentation on its flavor and quality, mackerel enzymatic hydrolysate was, fermented with Saccharomyces longosporus to enhance the flavor, and flavor and quality changes during different fermentation stages were monitored by measurement of total bacterial count and amino acid nitrogent content, sensory evaluation, and principal component analysis (PCA) of electronic nose data. Meanwhile, nutritional evaluation of the fermented product was carried out by analysis of free and essential amino acid composition, and the composition of flavor compounds was analyzed by gas chromatography-ion mobility spectrometry (GC-IMS). It was found that PCA effectively distinguished the flavor differences between the ultrasound and control groups during the fermentation process. The total bacterial count, amino acid nitrogen content and sensory score of the ultrasound group were higher than those of the control group during the whole fermentation process. On day 12 of fermentation, the ultrasound group had the best flavor quality with a total bacterial count of 8.90 (lg(CFU/mL)) and an amino acid nitrogen content of 0.78 g/100 g, and the fermented product had a rich umami taste and a fruity aroma. Moreover, the content of total free amino acids in the fermented product was 6.373 g/100 g, and the essential amino acid index (EAAI) value was 82.90, indicating a high nutritional value. GC-IMS results showed that the contents of off-flavor compounds such as, saturated straight-chain aldehydes gradually decreased, or even disappeared after 12 days of fermentation. In contrast, the contents of unsaturated alcohols and aroma-active substances (ketones and esters) significantly increased in the ultrasonic group compared with the control group. Thus, ultrasoundassisted treatment could improve the flavor quality of fermented mackerel enzymatic hydrolysate. This study may provide a theoretical basis for the application of ultrasonic technology in the development of seafood seasoning.

This study was carried out in order to investigate the effect of high-voltage electrostatic field (HVEF) treatment on the quality of fermented Engraulis japonicus. E. japonicus protein hydrolysate (EJPH) was inoculated with Lodderomyces elongisporus and fermented for different periods of time with different electric field action and intervention times. The fermentation conditions were optimized based on amino nitrogen content and sensory evaluation scores. Furthermore, the effect of HVEF treatment on the pH, total acid concentration and flavor of fermented EJPH was explored. The free amino acid composition of fermented EJPH was analyzed and its nutritional quality was evaluated based on essential amino acids. Its flavor composition was analyzed by headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The results showed that when the fermentation time was 15 days, electric field intervention time was 40 h after inoculation, and electric field treatment time was 30 min, the flavor and quality of the fermentation product were the best. Its amino nitrogen content was 0.72 g/100 mL, and the fermentation product had a strong fresh aroma along with a fruity aroma. The total amount of free amino acids was 54.798 mg/mL. The contents of umami and sweet amino acids were higher and the content of bitter amino acids was lower in the fermentation product than in the control group without HVEF treatment. The essential amino acids index (EAAI) value of the fermentation product with HVEF treatment was 71.07, indicating good nutritional quality. The HS-SPME-GC-MS results showed that compared with the control group, the HVEF group showed increased contents of aroma-active substances such as acids, alcohols and esters, and decreased contents of unpleasant flavor compounds such as straight-chain saturated aldehydes and fuel oil. Therefore, under appropriate conditions, HVEF treatment can improve the flavor quality of fermented E. japonicus.

In order to understand the microbial community composition and the evolution of volatile flavor substances during the fermentation process of grass carp with rice wine less and to explore the possibility of using rice wine mash instead of rice wine lees for the fermentation of grass carp, high-throughput sequencing technology was used for sequencing and phylogenetic analysis of the bacterial and fungal communities in unfermented grass carp and three groups of air-dried fermented grass carp (made with lees fermented for 5 days, lees fermented for 2 days and mash fermented for 2 days, respectively), and gas chromatography-ion mobility spectrometry (GC-IMS) was used to analyze their volatile flavor substances. The results showed that the contents of moisture, alcohol and amino acid nitrogen increased with fermentation time, and the pH decreased. The mash fermentation group had the best performance in smell, color, taste and texture, with good overall acceptability. The dominant bacterial genera were Weissella, Citrobacter and Aeromonas in the early stage of fermentation. In the middle and late stages, the abundance of Pediococcus and Lactococcu increased, while the abundance of Citrobacter and Aeromonas decreased significantly. For all three fermented samples, the dominant fungal genus Pichia had an absolute advantage during the fermentation process. A total of 37 volatile flavor substances were detected in all samples, among which acetic acid ethyl ester, ethyl propanoate and 2-butanone, 3-hydroxy were the characteristic flavor substances of fermented grass carp with lees. Weissella, Lactococcu, Pichia and Saccharomyces cerevisiae had a significantly positive correlation with the production of various aroma substances. This study provides the basis for the screening of dominant strains and the optimization of the fermentation process of fermented grass carp.