Food Hydrocolloids最新文献

The capacity of four formulations of natural deep eutectic solvents (NDESs) for extraction of canola protein was compared to alkaline extractions at pH 12 and pH 9. NDESs were prepared with a 1:2:1 ratio of choline chloride/d-sorbitol, glycerol, d-glucose or urea/water. The urea formulation showed the lowest viscosity and density and highest polarity; and extracted a bright-yellow isolate with extraction efficiency of 52.89% and protein content of 84.03%. The rest of NDESs extracted light-green isolates with efficiencies of approximately 44%. Furthermore, All NDESs offered lower extraction efficiencies than pH 12 (68.34%, dark-green isolate) but higher than pH 9 (39.14%, yellow isolate). Molecular analysis via SE-HPLC and SDS-PAGE showed the presence of cruciferins and napins in all isolates, but higher napin contents for NDES isolates with cruciferin-to-napin ratios of around 60:40. NDESs also altered the secondary and tertiary structure of the protein to a lesser extent. The functionality analyses at pH range of 3–7 revealed better solubility for pH 9 (72.09%–39.35%) and glycerol formulation (68.61%–39.05%) isolates; and better foaming properties for all NDES isolates, possibly due to their higher napin contents. NDES isolates also showed better emulsifying properties at pH 5 and 7, while alkaline isolates produced more stable emulsions at pH 3, possibly due to the better solubility of their cruciferins at pH 3. Overall, NDES isolates offered higher extraction efficiencies and a close functionality compared to pH 9 isolate, better color and functionality than pH 12 isolate, and better preservation of native protein structure compared to both alkaline treatments.

This study investigated the dual enhancement effect of five yeast extracts (YE) on gel properties and saltiness perception of low-salt (1% NaCl) surimi gels. The addition of YE not only pronouncedly enhanced the gel strength, texture properties (hardness, cohesiveness and chewiness) and elasticity of low-salt surimi gel (P < 0.05), but also increased the gelation rate of surimi during kamaboko stage. When YE was added, the water holding capacity of surimi gels increased, accompanied by decreased water fluidity, and composite gels exhibited a relatively dense and ordered microstructure. Electronic tongue analysis indicated that YE addition enhanced umami and saltiness, and decreased the sour and bitterness characteristic values (P < 0.05). Besides, sensory evaluation showed that YE increased the texture, saltiness, umami and smell score of low-salt surimi gel (P < 0.05), and the saltiness perception of low-salt surimi gel added with YE1 and YE2 was similar to normal-salt surimi gel (2% NaCl), which was consistent with the result of electronic tongue. The correlation analysis result revealed that the enhancement of gel properties of surimi may be attributed to the charged amino acids (Arg, Lys, His, Glu and Asp) in YE, and the umami substances (Glu, Asp, IMP and GMP) in YE could not only improve the umami taste, but also enhance the saltiness perception of low-salt surimi gel. Overall, YE had the dual effect of remarkably improving the gel properties and enhancing saltiness perception of low-salt surimi gel, providing a salt reduction effect, with YE2 being the best.

Academics and industry have invested in creating novel and functional ice creams to meet the growing demand for frozen foods that promote human health and nutrition. This study aimed to investigate the effect of medium-chain triglyceride (MCT) oleogels that prepared by three different gelators on the development of ice creams, as a complete substitute for hydrogenated palm kernel oil (HPKO). The results showed that both beeswax (BW) and phytosterol-oryzanol (PS-GO) caused the fat crystal to grow into three-dimensional spherulites, while ethylcellulose (EC) inhibited crystal size growth. Among the three types of oleogel-based ice creams, the BW sample exhibited the highest coalescence degree, followed by PS-GO and EC. The difference was due to variations in crystal growth and rigid crystal strength. Both BW and PS-GO oleogels improved the firmness of the ice creams by enhancing the formation of crystal network structures in the emulsions. The EC oleogel did not contribute to the overrun of the ice cream. The well-structured fat with partially coalesced aggregates can stabilize the bubbles and hold the aqueous phase of ice creams, preventing the outflow during meltdown. Oleogels that form crystal networks can be employed as a preferable replacement for HPKO in the production of ice cream with superior texture.

In fermentation to produce the alcoholic liquor baijiu, sorghum starch is the main carbohydrate source, being hydrolyzed and converted into ethanol and aromatics. The mechanisms of starch hydrolysis which affect fermentation quality and efficiency are not fully understood. To investigate this, three sorghum varieties were used as fermentation material, with two fermentation methods. Changes in the amounts of various components and in starch molecular structure in lees (sediment) during fermentation were investigated. The lees from waxy sorghum had higher fermentation rates and saccharification power than those from normal sorghum in the early stage of fermentation, but decreased below those of normal sorghum in the end stage of fermentation, due to increased accumulation of acid, which inhibited enzyme activities, and even stopped fermentation. The chain-length distributions of both amylopectin and amylose in the lees did not show significant changes with fermentation, showing that starch in sorghum grain cannot be hydrolyzed directly, but only by hydrolysis of starch leached from the grain into the water; this is in accord with data from electron micrographs indicating that starch hydrolysis happened in the leachate rather than in the lees. This information can help manufacturers fine-tune their processes to improve production processes and product.

Two microcapsules of Lactiplantibacillus Plantarum DNZ-4 (DNZ-4) with shell of casein-alginate (A-CDM) and casein-alginate-chitosan (CA-CDM) were prepared by the polymeric gel and layer-by-layer (LBL) encapsulation technique. These microcapsules with an encapsulation rate of 93.17% were compared with physicochemical properties, cell viability, storage, and application. The results showed that there was no significant difference in particle size between A-CDM (2.22 mm) and CA-CDM (2.35 mm). SEM images showed that CA-CDM became more regular and smoother after chitosan coating. FTIR analysis confirmed the presence of hydrogen bonds and electrostatic interactions in CDMs. The interaction between chitosan and alginate made the swelling ratio significantly lower than A-CDM in simulated gastric and intestinal fluid. Both microcapsules significantly improved cell viability under high temperature, low acidity, bile salts, storage, and gastrointestinal digestion, and CA-CDM demonstrated a better protective effect than A-CDM. The number of viable cells in beverages reduced by only 1.74 lg CFU/mL due to the protective effect of CA-CDM after pasteurized (63 °C, 30 min). Moreover, the cell counts were all above 7 lg CFU/mL stored at 4 °C for 28 days, and the pH and viscosity of the beverages changed slightly. Therefore, multilayer-coated microcapsules with casein-alginate-chitosan have great potential in protecting probiotics, target delivery, and applications.

High-performance liquid chromatography and linear-ion trap/Orbitrap high-resolution mass spectrometry (HPLC-LTQ/Orbitrap MS/MS) was used to trace the origin of porcine gelatin under different glycation reaction times. With the extension of the glycation reaction time, the characteristic peptides of porcine gelatin gradually decreased, indicating that the glycation reaction would have an impact on the identification of porcine gelatin. In addition, compared with the porcine gelatin theoretical characteristic peptide database, it was found that the number of characteristic peptides of porcine gelatin in the glycation reaction of 0, 24, 48, 72 and 96 h were 39, 84, 82, 73 and 70, respectively. Among them, 33 characteristic peptides did not change with the extension of glycation time. Compared with our previous research, 9 characteristic peptides were found to be common to porcine gelatins under the different food processing conditions. These stable common characteristic peptides could be used as an important basis for porcine gelatin traceability with high accuracy.

Interactions between proteins and polysaccharides can be used to design food ingredients with potential functional properties. However, the effects of the products formed through different interactions on the gut microbiota remain unclear. In this study, the functional properties and gut microbiota regulation of whey protein isolate (WPI), gum Arabic (GA), their physical mixture (WPI-GA-M) and Maillard conjugates (WPI-GA-C) were investigated in vitro, aiming to understand the effects of protein-polysaccharide conjugation on gut microbiota and to promote the potential applications of conjugates in the food industry. The results showed that WPI-GA-C prepared by Maillard reaction showed improved antioxidant, emulsifying, and anti-inflammatory properties than WPI, GA and WPI-GA-M. Moreover, WPI-GA-C showed unique effects in regulating the gut microbiota by significantly increasing the relative abundances of Bacteroides eggerthii and B. ovatus and enriching the pathways of carbohydrate metabolism and other amino acids metabolism. In brief, the conjugates showed better functional properties with the potential to improve human health by promoting the growth of beneficial bacteria.

Herein, pH combined with ionic strength was employed to modulate the charge distribution around ovalbumin molecules, and the whole process (from the water phase to the interface) of film formation and stabilization of ovalbumin at the air-water interface was further analyzed. As the pH continuously rose above the isoelectric point, the molecular surface charge increased. More cations, however, reduced the surface charge through the electrostatic shielding effect. The pH and cationic strength were shown to have a remarkable effect on the aggregate size. Intrinsic fluorescence and excitation emission matrix spectroscopy indicated that the migration of tryptophan and tyrosine was accompanied by a change in the backbone structure and rearrangement of the hydrophilic/hydrophobic side chains. Interfacial adsorption kinetic analysis revealed that low pH and ionic strength generally favored the adsorption and stabilization of ovalbumin. Lissajous plots confirmed that stronger intra-interfacial interactions and viscoelastic-like solid interfaces would be generated under the above conditions. Interfacial dilatational rheology analysis illustrated that in most cases, the interfacial film formed by ovalbumin was dominated by an elastic response and produced a nonlinear viscoelastic response under strain. Overall, the combined effect of low pH (pH 5.0) and ionic strength (25 mmol/L and 50 mmol/L) on the surface charge resulted in superior foam capacity (60.00% for pH 5.0 and 50 mmol/L) and stability (97.87% for pH 5.0 and 25 mmol/L). This study detailed the mechanism by which charge influenced the molecular and interfacial properties of ovalbumin, leading the way for the development of protein-based foam systems.

The present study investigated water-soluble pectin (WSP), chelating pectin (CSP), sodium carbonate-soluble pectin (NSP), and cyanidin-3-O-glucoside (C3G). Various ultrasonic treatments (688, 1376, 2064, 2431, and 3437 W/cm², 10 min) were used to modify the three types of pectin, and the structural changes in pectin and the interaction mechanisms between pectin and cyanidin were analysed. The experimental results indicated that ultrasonic (US) modification reduced the molecular weight and degree of methylation (DE) of pectin. The DE values of WSP and CSP decreased by 24.51% and 80.12%, respectively. US modification disrupted the branched structure of pectin and reduces the ratio of rhamnose/galacturonic acid, which caused an increase in the linearity of pectin. US modification enhanced the interaction between the three pectins and anthocyanins, and the US condition of 2064 W/cm² for 10 min increased the binding rate by 15.71%–46.18%. NSP had the largest binding rate, and US modification had the greatest improvement in WSP binding rate. After US modification, the particle size of the pectin-cyanidin complex decreased, and the zeta potential increased. After heat treatment, the residual mass percentage of the pectin-C3G complex increased, which suggested that the encapsulation of C3G in pectin improved thermal stability. Therefore, US treatment is a versatile processing tool that reduces the DE of pectin and enhances its linearity, which offers a promising approach to promoting pectin-C3G complexes.

Collagen, with its most characteristic structural unit, the triple helix, has wide applications in pharmaceutical and cosmetic industries. However, the application of collagen is limited by its poor thermal stability, especially fish collagen. Fish collagen, despite its abundance and eco-friendly sourcing, faces challenges like low melting temperatures and mechanical fragility due to its distinct composition. In this study, the focus was on exploring strategies to enhance the stability of fish collagen for potential human applications. To address this, our research investigated a non-covalent binding strategy, by using heat shock protein 47 (Hsp47) from zebrafish and human to stabilize fish collagen. The co-application of Hsp47 dramatically improved the rates of folding and markedly increased the denaturation temperature of fish collagen from 31.7 °C to 37.7 °C, demonstrating promising outcomes for potential in vitro applications. Optical Nanoscopy Electron Microscopy (OpNS-EM) imaging demonstrates the complex formation between Hsp47 and collagen fibers, shedding light on their interaction dynamics, while cytotoxicity assays affirm the safety of the Collagen-Hsp47 complex on human keratinocytes. This pioneering methodology applies a viable approach to stabilize fish collagen, expanding its potential applications across human-related domains.