Influence of hydrophilic polysaccharide fat replacers on the in vitro digestibility of protein in emulsion-type sausage

Insight into the digestion mechanism of proteins in silver carp (Hypophthalmichthys molitrix) surimi by different alginates

This study aimed to evaluate the impact of potassium alginate (PA), propylene glycol alginate (PGA), and calcium alginate (CA) on the gel properties of silver carp (Hypophthalmichthys molitrix) surimi (control group) throughout gastrointestinal digestion. The findings revealed that the protein digestibility of the PA/PGA and CA groups was found to be lower compared to the control group. Among these groups, the CA group had the lowest digestibility rate at 82.49 ± 3.50 %. The study revealed a reduction in the number of peptides found in the surimi group treated with alginate compared to the control group. Alginate was discovered to have inhibitory effects on proteolysis by forming a robust cross-linked network that obstructs pepsin from accessing its substrates. This research provides valuable insights into the potential application of alginate for improving the digestibility of surimi proteins and creating commercial surimi products.

Replacement of backfat with vegetable oils or their oleogels in emulsion-type sausage significantly change the digestibility of meat protein

Replacing animal fat with vegetable oil occurred extensively in the meat products, but whether these replacements will affect the nutrition of meat protein was seldom revealed. Effect of substitution of back fat (BF) by vegetable oils or their oleogels in emulsion-type sausage on the digestion process of meat protein was investigated. Replacement of BF with vegetable oils and their oleogels decreased the G'/G" values of meat paste, and oleogels largely weakened the structure of sausages. The substitution significantly reduced the liberation of -NH2 during the initial gastric and intestinal digestion, and resulted in bigger digests in CLSM images. The reduced gastric digestibility induced by substitution was shown to be related to the reduced stability of gastric digests, which can be attributed to the larger particle size and reduced viscosity of digests. These results highlighted stability of digests as a key point changing the digestion process of meat protein.

Amelioration of tiger nut insoluble dietary fiber as a partial substitute for fat in meat emulsions: Techno-functional properties and in vitro protein digestibility

The effects of tiger nut insoluble dietary fiber (TNF) (1%-3% w/w) on techno-functional properties and in vitro protein digestibility of low-fat meat emulsions were examined. The results showed that TNF (especially 2% and 3%) could improve techno-functional performances of low-fat meat emulsions in terms of water binding capacity and textural attributes, which were even preferable to the high-fat control. The improvements were associated with the attenuated fluidity of inner water within the gels, the increased storage modulus (G'), the formation of a well-joined gel network with uniformly-dispersed fat particles and the uncoiling of α-helix and the formation of β-sheet. The weakened water mobility, the heat-triggered conformational shift from α-helix to β-sheet, as well as less and evenly distributed fat particles ulteriorly led to elevated protein digestibility in meat emulsions. Therefore, TNF shows promise as a fat substitute to develop fat-reduced emulsified pork meat products with desirable quality and digestion behaviors.

Encapsulation and release of salidroside in myofibrillar protein‑sodium alginate gel: Effects of different M/G ratios of sodium alginate

Myofibrillar protein‑sodium alginate (MP-SA) gels play a pivotal role in the development of functional food gels. Salidroside (SAL) is promising component but suffers from low bioavailability, necessitating effective delivery systems. This study introduces M/G ratio factor into classical theoretical MP-based gel models, and use for the SAL delivery. The findings indicate that SA significantly enhances gel properties and functions. Scanning electron microscopy, liquid chromatography, and low-field nuclear magnetic resonance confirmed that the addition of SA improved microstructure, water retention, and thus reduced SAL loss during processing. Digestion simulations revealed the influence of SA type on SAL release kinetics. Molecular docking showed that SA with lower M/G ratio binds more readily to MP, a key determinant of gel performance. These insights provide a novel theoretical basis for MP-SA gels and offer a new perspective on the delivery of bioactive compounds in functional foods.

Starch in Emulsion-Type Sausage Reduced the Gastric Digestibility of Meat Protein by Reducing the Stability and Increasing the Viscoelasticity of Gastric Digests

The effect of the addition of native starch (S) and modified starches (distarch phosphate (SP), acetylated distarch phosphate (AP), and starch acetate (SA)) in emulsion-type sausage on the digestion process of meat protein was studied in this work. The addition of native and modified starches reduced the release of -NH2 during the simulated gastric digestion stage, whereas the addition of SA increased the total release of -NH2 after the whole digestion. Peptidomic analysis revealed that the presence of starch decreased the release of peptides in the gastric digestion. The presence of starch reduced the stability of the digests but increased the viscosity of the gastric digestive fluid, which should largely be responsible for the decreased gastric digestibility of meat protein. These results highlighted the physical properties of digests as a key factor affecting the gastric digestion process of meat protein and provided guidance for the application of starches in meat products.

Real-time monitoring of peptic and tryptic digestions of immunoglobulin G and the impact of dietary hydrocolloids on digestion

Immunoglobulin G (IgG) exhibits potent antiviral, antibacterial, and immunological activities. The digestion process and bioavailability of IgG are often a concern. Dietary hydrocolloids are crucial for regulating healthy digestion and the bioavailability of protein as functional components. Understanding the effects of dietary hydrocolloids on the digestive kinetics of IgG is requisite. Herein, the pepsin and trypsin digestion of IgG was investigated using ordered porous layer interferometry (OPLI). The real-time variation in the interference spectral shift reflected by OPLI can be converted into changes in the optical thickness (OT) to obtain a degradation kinetics curve. The impact of dietary hydrocolloids, including alginic acid sodium salt (ALG), polydextrose (PD), and konjac glucomannan (KG), on IgG degradation was evaluated using OPLI. The results demonstrated that ALG significantly inhibited the degradation of IgG by pepsin under acidic conditions, whereas the addition of PD increased the Michaelis-Menten constant for IgG degradation by trypsin. Notably, this dependence is not based on the hydrocolloid viscosity, but relies more on the electrical properties. The study enhances our understanding of how hydrocolloids affect IgG digestion and could provide valuable insights into preserving IgG activity and facilitating the development of oral drugs or health products related to IgG.

Effect of fat concentration on protein digestibility of Chinese sausage

Chinese sausage is a popular traditional Chinese meat product, but its high-fat content makes consumers hesitant. The purpose of this study is to compare the nutritional differences of Chinese sausages with different fermentation times (0, 10, 20, 30 d) and fat content (the initial content was 11.59% and 20.14%) during digestion. The comparison of digestion degree, protein structure, and peptide composition between different sausages were studied through in vitro simulated digestion. Chinese sausages with high-fat content had higher α-helix, β-turn, and random coil, making them easier to digest. The fermentation process made this phenomenon more pronounced. The high-fat sausage fermented for 10 d showed the highest release of primary amino acids (about 9.5%), which was about 3.5% higher than the low-fat sausage under the same conditions. The results of peptidomics confirmed the relevant conclusions. After gastric digestion, the types of peptides in the digestive fluid of high-fat sausages were generally more than those in low-fat sausages, while after intestinal digestion, the opposite results were observed. The type of peptide reached its peak after fermentation for 20 d. These findings are of obvious significance for selecting the appropriate fermentation time and fat content of Chinese sausages.