Comprehensive Effects of Potassium Lactate, Calcium Ascorbate and Magnesium Chloride as Alternative Salts on Physicochemical Properties, Sensory Characteristics and Volatile Compounds in Low-Sodium Marinated Beef.

The search for alternative salt formulations similar to sodium chloride and their effect on marinated meat products is of great significance to the low-sodium meat processing industry. The main purpose of this study was to investigate the effect of partially replacing sodium chloride with potassium lactate, calcium ascorbate, and magnesium chloride on the sodium content, water activity and distribution, protein solubility, microstructure, sensory characteristics and volatile flavor compounds in low-sodium marinated beef. The sodium content in the test group decreased up to 28% compared to 100% in the sodium chloride group C1. The formulation including 60% sodium chloride and a total of 40% compound alternative salts in groups F1 and F2 increased their myofibril fragmentation index and promoted the disruption of the myogenic fiber structure. Group F1 (the ratio of potassium lactate, calcium ascorbate and magnesium chloride was 2:1:1) performed higher solubility of myofibrillar proteins and lower transverse relaxation value than group F2 detected by low-field nuclear magnetic resonance, which indicated that F1 formulation was beneficial to promote the solubility of myofibrillar proteins and attenuate the water mobility of marinated beef. Moreover, group F1 had a more similar microstructure and more similar overall sensory attributes to group C1 according to the scanning electron microscopy. The sensory evaluation showed higher peak intensity and response values of volatile flavor compounds than group C1 and C2 (only 60% sodium chloride) when detected using gas chromatography-ion mobility spectrometry technology, which indicated that the compound alternative salts of group F1 can improve the lower quality of low-sodium marinated beef and perform similar attributes to the C1 sample regarding moisture distribution and microstructure and even performs better than it with regards to flavor. Therefore, the F1 formula possessed greater potential for application in low-sodium marinated meat products.

Difference in the adhesion of Bifidobacterium breve to lotus seed resistant starch is attributable to its structural performance conferred by the preparation method.

Resistant starch (RS) is a kind of important carbon source for colonic microorganisms. Its structure-function relationship is helpful to understand the mechanism of dietary nutrition in the body. In this paper, lotus seed resistant starches (LRS) prepared by microwave-power method (MP-LRS3-1 and MP-LRS3-2) and water-bath method (WB-LRS3-1 and WB-LRS3-2) were used to determine the structural changes and establish their nutritional interactions with Bifidobacterium breve. The results showed that four types all formed scale- and gully-like surface microstructures, B-type crystal structures, and lightly variable double helix structures. However, greater diffraction peak intensity was observed of MP-LRS3 at 18° and 19° compared with WB-LRS3, and higher crystallinity and tighter double helix were detected in MP-LRS3-1 than others. Meanwhile, MP-LRS3-1 showed the most effective proliferation promoting capability and highest adhesion value to B. breve. It might be related to specific surface microstructure and crystallinity differences of LRS caused by different preparing methods. There was also a positive correlation between the adhesion and the ability to promote proliferation, and it could be speculated this structural difference makes MP-LRS3-1 having highest adhesion ability and the most proliferative effect. This result can provide theoretical bases for improving the metabolism and probiotic action of RS.

Effects of oligosaccharides on particle structure, pasting and thermal properties of wheat starch granules under different freezing temperatures.

The effects of fructooligosaccharides (FOS), galactooligosaccharides (GOS), and xylooligosaccharides (XOS) on gelatinization, retrogradation, thermal properties and particle size of wheat starch at different freezing temperatures were studied. The results showed that the wheat starch porosity, particle size, peak viscosity increased with increasing freezing temperature. With the addition of 16% oligosaccharides to starch, the porosity, particle size, crystallinity, initial gelatinization temperature, peak value, breakdown and retrogradation viscosity of the starch granules significantly decreased in the order of XOS > GOS > FOS. However, the pasting temperature of the granules increased. The addition of oligosaccharides (especially XOS, which has the most significant effect in inhibiting starch retrogradation) can inhibit the formation of starch crystal structures to a certain extent, reduce the damage from ice crystals to starch granules and delay starch retrogradation. Therefore, functional oligosaccharides can be used as a potentially effective additive to increase freezing stability in frozen starch-based foods.

Lotus seed oligosaccharides at various dosages with prebiotic activity regulate gut microbiota and relieve constipation in mice.

The aim of this study was to evaluate the effects of lotus seed oligosaccharides (formulation consisting of LSO2, LSO3-1, LSO3-2 and LSO4; relative ratios are 1.107:0.554:0.183:0.443, m/m/m/m) at dosages of 0.42, 0.83 g/d/kg bw and 2.49 g/d/kg bw on the microbiota composition and the propulsion of intestinal contents in the gut of mice. The results showed that fecal water content increased in treated mice; there was less gut microbiota diversity than in other groups; and there was a large number of fauna in the cecum of the mice. At the same time, the number of short-chain fatty acid (SCFA) bacterial producers increased after feeding with oligosaccharides; Lotus seed oligosaccharides (LOS) also enhanced the concentration of SCFAs in the intestine, which also increased the concentration of cytokines in the serum of mice. In conclusion, these findings suggest that LOS or combination with resistant starch has a better effect on relieving constipation.

Phenotypic, fermentation characterization, and resistance mechanism analysis of bacteriophage-resistant mutants of Lactobacillus delbrueckii ssp. bulgaricus isolated from traditional Chinese dairy products.

Bacteriophage infection is a large factor in dairy industrial production failure on the basis of pure inoculation fermentation, and developing good commercial starter cultures from wild dairy products and improving the environmental vigor of starter cultures by enhancing their phage resistance are still the most effective solutions. Here we used a spontaneous isolation method to obtain bacteriophage-resistant mutants of Lactobacillus delbrueckii ssp. bulgaricus strains that are used in traditional Chinese fermented dairy products. We analyzed their phenotypes, fermentation characteristics, and resistance mechanisms. The results showed that bacteriophage-insensitive mutants (BIM) BIM8 and BIM12 had high bacteriophage resistance while exhibiting fermentation and coagulation attributes that were as satisfying as those of their respective parent strains KLDS1.1016 and KLDS1.1028. According to the attachment receptor detection, mutants BIM8 and BIM12 exhibited reduced absorption to bacteriophage phiLdb compared with their respective bacteriophage-sensitive parent strains because of changes to the polysaccharides or teichoic acids connected to their peptidoglycan layer. Additionally, genes, including HSDR, HSDM, and HSDS, encoding 3 subunits of a type I restriction-modification system were identified in their respective parent strains. We also discovered that HSDR and HSDM were highly conserved but that HSDS was variable because it is responsible for the DNA specificity of the complex. The late lysis that occurred only in strain KLDS1.1016 and not in strain KLDS1.1028 suggests that the former and its mutant BIM8 also may have an activatable restriction-modification mechanism. We conclude that the L. bulgaricus BIM8 and BIM12 mutants have great potential in the dairy industry as starter cultures, and their phage-resistance mechanism was effective mainly due to the adsorption interference and restriction-modification system.