The aim of this study is to clarify the effects of ultrafine ground pea dietary fiber (UGPDF) on the intestinal microflora and metabolites of diabetic mice so as to reveal the mechanism of its hypoglycemic effect. A diabetic mouse model was established by intritoneal injection of streptozotocin, and the diabetic mice were gavaged with either metformin or UGPDF with high-dose (0.9 g/ (mL·d)) and low-dose (0.45 g/ (mL·d)) for four weeks. The changes in blood glucose level and liver cell morphology were measured during the experimental period. The protein expression levels of phosphatidylinositol-3-kinase (PI3K), protein kinase B (AKT) and insulin-like growth factors (IGF) were detected by Western blot. The composition of the fecal microbial flora of mice in each group was analyzed by high-throughput sequencing. The results showed that UGPDF could regulate the abundance and diversity of the intestinal microflora in diabetic mice. The number of operational taxonomic units (OTUs) in the high-dose UGPDF group was 300 ± 36, and the Shannon and Simpson indexes of this group were significantly different from those of diabetic mice. UGPDF intervention increased the abundance of beneficial bacteria such as Lactobacillus and Lachnospiraceae (P < 0.05), and decreased the abundance of pathogenic bacteria such as Helicobater, Klebsiella compared to the model group (P < 0.05). Moreover, after UGPDF intervention, the contents of six short-chain fatty acids in the feces of mice were significantly increased, and the most significant effect was observed in the high-dose group, showing an increase in the contents of acetic acid, propionic acid and butyric acid by 63.7%, 75.9% and 96.0%, respectively, reaching a level similar to that of the normal group. At the same time, the results of liver Histological examination and Western blot showed that UGPDF could regulate the PI3K/AKT/IGF signaling pathway in the liver of diabetic mice, repair liver cell injury and improve insulin sensitivity.

In this study, the effect of dynamic high pressure microfluidization at different pressures on the structural and functional properties of pea albumin and its complex with chlorogenic acid was investigated by measuring particle size, zeta potential, fluorescence spectra, infrared spectra, hydrophobicity, solubility and emulsification properties. The mechanism of the influence of chlorogenic acid on pea albumin in the binary system was explored. The results showed that after dynamic high pressure microfluidization treatment, the particle size and zeta potential of pea albumin firstly decreased and then increased. The microstructure, secondary structure and tertiary structure of pea albumin were changed. The solubility of small pea albumin particles was significantly increased by 42.37%, reaching 0.84 mg/mL under the action of shear force and other effects (P < 0.05), and the emulsification characteristics were also enhanced. The addition of chlorogenic acid changed the microenvironment of tryptophan residues in pea albumin, which led to significant changes in the structure of pea albumin. Meanwhile, it significantly increased the surface hydrophobicity and decreased the solubility of pea albumin (P < 0.05), and improved the solubility. This study provides an idea for pea albumin modification and a theoretical foundation for the development of high-value protein products.

Three-dimensional food printing (3DFP) is an efficient way of food processing in line with the future lifestyle. As a delivery system, hydrogel has become a research hotspot because of its remarkable characteristics such as directed delivery. The purpose of this study was to explore the effects of 3DFP on the structure, physical properties and functions of hydrogels containing methylcellulose (MC), chlorogenic acid (CA) and hyaluronic acid (HA) for the purpose of revealing the printability and applicability of hydrogels in 3DFP processing. Texture properties, rheological properties, microstructure, embedding rate and digestive properties of the 3D printed products were measured. The results showed that the best CA-loaded hydrogel system for 3DFP processing consisted of MC, HA and CA at a mass ratio of 8:0.5:0.5. Its printed product showed the smallest width deviation (13.40%), the highest hardness, the maximum elasticity, and the minimum adhesiveness, had compact structure and uniform porosity, was not easy to collapse, and had good supportability and the best printing moldability. 3DFP well optimized the physical structure of hydrogel without changing its chemical properties. The embedding rate of CA was 22.09 percentage points higher than that before 3D printing. In simulated gastrointestinal digestion test, the release rate of CA from the printed product was significantly higher than that of the unprinted samples, showing a good sustained release effect, and the in vitro release of CA was fitted to the Ritger-Peppas model. These results showed that the hydrogel system had good printability and applicability, and 3DFP could significantly improve the targeted release of CA loaded in hydrogel.

A composite film was developed using pea protein (PP) as the film-forming substrate, chitosan (CS) as the film-modifying material, chlorogenic acid (CA) as the functional component, tyrosinase (Tyr) as the cross-linking agent, and glycerol as the plasticizer. The physical parameters and microstructure of the PP-CA-CS film were determined. The aim was to explore the effects of PP-to-CS ratio and the concentrations of CA and Tyr on the structure and properties of the composite film and to study the interaction between its components. The results showed that the antioxidant potential and mechanical properties of the composite film were significantly improved after the addition of CA, and Tyr catalyzed the covalent cross-linking of CA with PP and CS. With the addition of CA and Tyr, the cross-linking degree and mechanical properties were improved. At a PP-to-CS ratio of 1:1, at 20 mmol/L CA concentration and at 18 U/mL Tyr concentration, the composite film had the best mechanical properties, antioxidant properties and water vapor barrier properties. In addition, the tensile strength of the film was 130.78 MPa, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity was 69.05%. Compared with pure PP-CS film, the mechanical properties of the PP-CA-CS composite film were increased by 3.6 times, the antioxidant potential was increased by 3.2 times, and the water vapor permeability was decreased by 8%. The results of scanning electron microscopy (SEM) showed that the PP-CA-CS composite film was smooth and compact, so it had high water vapor barrier performance. No new functional groups were generated in the film formation process as demonstrated by infrared spectral analysis. Therefore, this study provides a new idea for researchers in the field of new food packaging, and offers data and theoretical support for the development of edible films.

A physically cross-linked hydrogel was constructed by electrostatic interaction between chitosan (CS) and sodium hyaluronate (SH), and its texture properties, microstructure and functional properties were characterized. Meanwhile, the influence of loading with one of the probiotics Lactobacillus rhamnosus and Pediococcus acidilactici on texture characteristics and microstructure of the hydrogel was evaluated, the loading performance was analyzed, and the release mechanism of probiotic-loaded hydrogels in simulated gastroenteric fluid was explored. The results showed that CS-SH hydrogel, which was formed through electrostatic crosslinking, had good texture properties and bacteria-loading properties, and the loading capacity of 0.2 g (dry mass) of hydrogels for L. rhamnosus and P. acidilactici was 1.15 × 10⁹ and 1.25 × 10⁹ CFU, respectively. The probiotic-loaded hydrogel was continuously released in simulated intestinal fluid, and its release mechanism was through surface erosion. The maximum viable counts of L. rhamnosus and P. acidilactici in simulated intestinal fluid were 6.30 and 6.12 (lg(CFU/mL)), respectively. To sum up, CS-SH hydrogel is a potential probiotic delivery carrier that can be continuously released in simulated intestinal fluid. This study provides theoretical guidance and a research basis for the application and mechanism of action of physically crosslinked hydrogels in the field of probiotic loading.