Gelling properties of silver carp surimi incorporated with konjac glucomannan: Effects of deacetylation degree

Regulation of glycose and lipid metabolism and application based on the colloidal nutrition science properties of konjac glucomannan: A comprehensive review

The physicochemical properties of dietary fiber in the gastrointestinal tract, such as hydration properties, adsorption properties, rheological properties, have an important influence on the physiological process of host digestion and absorption, leading to the differences in satiety and glucose and lipid metabolisms. Based on the diversified physicochemical properties of konjac glucomannan (KGM), it is meaningful to review the relationship of structural characteristics, physicochemical properties and glycose and lipid metabolism. Firstly, this paper bypassed the category of intestinal microbes, and explained the potential of dietary fiber in regulating glucose and lipid metabolism during nutrient digestion and absorption from the perspective of colloidal nutrition. Secondly, the modification methods of KGM to regulate its physicochemical properties were discussed and the relationship between KGM's molecular structure types and glycose and lipid metabolism were summarized. Finally, based on the characteristics of KGM, the application of KGM in the main material and ingredients of fat reduction food was reviewed. We hope this work could provide theoretical basis for the study of dietary fiber colloid nutrition science.

Exploring the versatility of carbohydrates in surimi and surimi products: novel applications and future perspectives

Carbohydrate is one kind of the most important additives in the production of surimi and surimi products, mainly due to its wide range of sources and superior functionality. In recent years, new carbohydrates (oligosaccharides and polysaccharides) have been gradually applied in the production of surimi and surimi products which is mainly driven by consumer requirement on nutritional and the flavors or taste quality and producer requirement on extending the shelf life, like low calorie intake, dietary fiber enrichment, rich taste and improvement of antioxidant properties. Besides anti-freezing and improvement in gelling ability, novel functionalities have been explored such as fat substitution, improving flavor, antibacterial effect, antioxidant effect and improving three-dimensional printability. With an in-depth study of the mechanism of carbohydrate improving the qualities of surimi and surimi products, the application of carbohydrates in surimi would be more effective. Therefore, this review summarizes the new carbohydrates applied in the processing of surimi and surimi products, and their novel functionalities. Additionally, progress of the research on the mechanism of carbohydrate improving the qualities of surimi is also reviewed. © 2023 Society of Chemical Industry.

Quality, Thermo-Rheology, and Microstructure Characteristics of Cubic Fat Substituted Pork Patties with Composite Emulsion Gel Composed of Konjac Glucomannan and Soy Protein Isolate

Composite emulsion gel can effectively mimic animal adipose tissue. In this study, composite emulsion gels composed of soy protein isolates and konjac glucomannan (KGM) were prepared as plant-based cubic fat substitutes (CFS). The effects of CFS on the quality and structure of pork patties were investigated in terms of the proximate composition, lipid oxidation stability, technological characteristics, color, sensory attributes, texture, thermo-rheological behavior, and microstructure. CFS samples composed of various ratios of KGM were added to lean meat patties to ascertain the optimal CFS composition for its potential replacement of pork back fat in patties. The addition of CFS containing 7.0% KGM was found to decrease the hardness of the lean meat patties by 71.98% while simultaneously improving their sensory quality. The replacement of pork back fat with CFS also reduced the fat content of the patties to as little as 3.65%. Furthermore, the addition of CFS enhanced the technological characteristics, lipid oxidation stability, and surface color of the fat-replaced patties, with no significant impact on their overall acceptability. The gel network of the patties was shown to be fine and remained compact as the fat replacement ratio increased to 75%, while the texture parameters, storage modulus, and fractal dimension all increased. Quality and structure improvements may allow the composite emulsion gels to replace fat in pork patties to support a healthy diet. This study may be beneficial for the application and development of plant-based cubic fat substitutes.

A mini review on manipulation of carbohydrate for better use in surimi and surimi products: modification and compounding

Carbohydrate is widely used in the production of surimi and surimi products to improve their qualities, such as anti-freezing capability, gelling ability, nutrition, flavor and 3D printability. More and more native carbohydrates have been modified through physical methods (e.g., ball milling, irradiation and differential sedimentation), chemical method (e.g., deacetylation, hydroxypropylation and acetic acid esterification) or enzymatic method (e.g., chitosanase) before being used in the processing of surimi and surimi products in recent years. At the same time, different carbohydrates are compounded and applied to surimi and surimi products. The modified and compounded carbohydrates in surimi have been proved to improve quality of surimi and surimi products more pronouncedly than native carbohydrates. Therefore, this review summarizes the manipulation of carbohydrate by modification and compounding to improve the qualities of surimi and surimi products. Moreover, the prospects for carbohydrate modification and compounding for use in surimi and surimi products are discussed. © 2023 Society of Chemical Industry.

Protection of Whey Polypeptide on the Lipid Oxidation, Color, and Textural Stability of Frozen-Thawed Spanish Mackerel Surimi

Repeated freeze-thaw (FT) cycles can have an impact on surimi quality. In this study, we used 0.02% BHA as a positive control group. We examined the effects of different concentrations (0%, 5%, 10%, and 15%) of whey protein hydrolysate (WPH) on surimi, focusing on alterations in color metrics (L* for brightness, a* for red-green, b* for yellow-blue, and overall whiteness), textural characteristics, and antioxidant capacity during various freeze-thaw (FT) cycles. The results showed that the lipid oxidant values of surimi, as well as its a* and b* values, rose as the number of FT cycles increased; whereas the adhesiveness, resilience, gumminess, and shear force dropped, as did L* and the whiteness values, leading to an overall darkening of color and gloss. By contrast, the study found that the addition of WPH could effectively slow down the decrease of surimi textural stability after repeated freeze-thawing, with the textural stability of the group with 15% WPH being significantly superior to those of the other groups (p < 0.05). Under the same number of cycles, adding 15% WPH to the experimental group could successfully lower total volatile basic nitrogen (TVB-N) and effectively increase the antioxidant activity of surimi. This finding suggested that 15% WPH had the greatest effect on increasing surimi FT stability. To conclude, it was proved that WPH can be added to frozen surimi and improve its quality.

Comprehensive review: by-products from surimi production and better utilization

Over 1 million MT of surimi is produced globally, which theoretically would generate approximate 2 million MT of solid by-products and more than 1 million MT of wash water. Utilization of the by-products has increasingly become interested based on their nutritional, economical, and environmental issues. Surimi by-products represent an important source of valuable compounds such as functional protein, collagen, gelatin, fish oil, peptides, minerals, and enzymes. Better utilization of the by-products would make the surimi industry sustainable and profitable. This review paper characterizes sources and composition of the solid by-products and wash water generated from the surimi production as well as factors related to extraction and processing techniques. In addition, the potential food applications are explored including specialty foods and snacks, flavor ingredients, bioactive ingredients, and functional ingredients. Moreover, an outlook summarizing the challenges and prospects on the utilization of surimi by-products is provided.

Effect of Flammulina velutipes polysaccharides on the physicochemical properties of catfish surimi and myofibrillar protein oxidation during frozen storage

This study investigated the effect of Flammulina velutipes polysaccharides (FVPs) on the myofibrillar protein (MP) oxidation protein and physicochemical properties of catfish surimi during 75 days of frozen storage at -18°C. FVP was added to surimi at 1%, 1.5%, and 2%, respectively; the degree of MP oxidation and the physicochemical properties of the surimi were investigated, and the microstructure of the surimi was observed by scanning electron microscopy (SEM). The results showed that the carbonyl content and the thiobarbituric acid reactive substances (TBARS) in the FVP groups were lower than those in the CK group (the blank surimi). In comparison, the total sulfhydryl content, solubility, and Ca2+-ATPase activity were higher than those in the CK group after 75 days of storage. The addition of FVP significantly increased the water-holding capacity (WHC), gel strength, elastic modulus (G'), and loss modulus (G") of surimi, and made the gel of surimi have stronger continuity and a denser structure. Therefore, FVP has a better cryoprotective effect on surimi. It improves the quality of surimi, decreases MP oxidation, and reduces lipid and water loss during frozen storage. The anti-freezing effect of FVP added at 2% was similar to that of commercial protectants (4% sucrose and 4% sorbitol).

Ultrasonic treatment combined with curdlan improves the gelation properties of low-salt Nemipterus virgatus surimi

In this study, the gel properties of ultrasonic alone, curdlan treatment alone, and the combination of both at low-salt surimi levels were investigated, mainly in terms of textural properties, water holding capacity, water distribution, dynamic rheology, protein secondary structure, microstructure and correlation analysis. The results showed that the springiness, gel strength, water holding capacity and energy storage modulus (G') of the low-salt surimi gels without ultrasonic or curdlan treatment were lower than those of the high-salt concentration surimi gels. Compared with the 1 % low-salt group, the ultrasonic treatment combination with curdlan resulted in a significant improvement (p < 0.05) in the texture, water holding capacity and energy storage modulus (G') of the low-salt surimi at the same salt concentration. The gel strength increased significantly from 3386.360 g·mm to 5457.203 g·mm, but there was no significant improvement in whiteness (p > 0.05). In addition, ultrasonic treatment combined with curdlan promoted the shift of the α-helix to the random coil and the β-turn angle shift, thus exposing the internal groups, enhancing protein intermolecular interactions, and promoting the orderly aggregation of proteins, resulting in a microstructure of dense, and obtained the lowest porosity of 14.534 %. The present study might be necessary for promoting the high-value use of aquatic surimi products and the development of low-salt foods.

Properties of whey protein isolation/konjac glucomannan composite gels: Effects of deacetylation degrees

The effects of konjac glucomannan (KGM) with different deacetylation degrees (DDs) on the gel properties of whey protein isolate (WPI) were investigated. The appropriately deacetylated KGM (DDs in the range of 0-53.85 %) incorporated within WPI and formed relatively uniform compound gels, while excessive deacetylated KGM (DDs = 63.46 or 71.63 %) caused macroscopic precipitation and aggregation in WPI-KGM system. The water holding capacity of WPI-KGM gels decreased with the gradual increase of DDs, and the removal of acetyl groups reduced the whiteness of the composite gels. The hardness and chewiness of the composite gel tended to increase and subsequently decrease with the enhancement of DDs, and reached the maximum (244.15 and 148.88 g, respectively) at the DDs of 53.85 %. The rheological analysis indicated that rigid structured WPI-KGM gels could be formed when incorporated with moderately deacetylated KGM. The deacetylated KGM (DDs = 53.85 %) enhanced the hydrogen bond and disulfide bond within the mixed system, resulting in a more compact network structure of the composite gels. Moreover, deacetylated KGM particles might also reinforce the gel strength by the "filling effects". Overall, the gelation characteristics of the WPI-KGM system can be regulated by controlling the DDs of KGM.

Effect of Black Tea Powder on Antioxidant Activity and Gel Characteristics of Silver Carp Fish Balls

The effect of black tea powder on the antioxidant activity and gel characteristics of fish balls from silver carp were investigated after freezing storage for 7 days. The results show that black tea powder with different concentrations of 0.1%, 0.2% and 0.3% (w/w) could significantly increase the antioxidant activity of fish balls (p < 0.05). In particular, at the concentration of 0.3%, the antioxidant activity was the strongest among these samples, where the reducing power, DPPH, ABTS and OH free radical scavenging rate were up to 0.33, 57.93%, 89.24% and 50.64%, respectively. In addition, black tea powder at the level of 0.3% significantly increased the gel strength, hardness and chewiness while greatly reducing the whiteness of the fish balls (p < 0.05). ESEM observation found that the addition of black tea powder could promote the crosslinking of proteins and reduced the pore size of the gel network structure of the fish balls. The results suggest that black tea powder could be used as a natural antioxidant and gel texture enhancer in fish balls, which we found to be much related to the phenolic compounds of black tea powder.

Thermal and Rheological Performances Evaluation of a Modified Biopolymer for Fracturing Fluid System

Developing an efficient fracturing fluid system is an enduring hot topic in the petrochemical industries, especially regarding the exploitation of limited oil. Biopolymers, especially polysaccharides (e.g., konjac gum, guar gum), are widely applied as fracturing fluids in fracturing as a result of their advantages. Herein, we propose an easy method of modifying konjac gum (KGM) using isopropanol, sodium hydroxide, and chloroacetic acid to obtain modified konjac glum (MKGM). The MKGM and KGM gels were also obtained by using the self-prepared organic titanium high-temperature stabilizer and organic borate cross-linker. The prepared MKGM was characterized by multiscale techniques, including attenuated total reflection Fourier transform infrared (ATR-FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and rheology properties. The ATR-FTIR results showed that the etherification modification reaction occurred as designed. The XRD results showed that the regularity of KGM was destroyed after modification. The TGA and DSC results showed that the thermal stability improved. Rheology measurements illustrated that the temperature and shear resistance of MKGM were better than those of KGM. The MKGM gel could be applied in fracturing fluid systems at a lower frequency through viscoelastic measurements.

Impacts of agar gum and fucoidan on gel properties of surimi products without phosphate

Phosphate is widely used in surimi products to improve the gel properties. However, excess addition of phosphate occurs, which can harm the consumer's health. This study aimed to evaluate the effects of agar gum and fucoidan on maintaining the gel properties of surimi products instead of phosphate. Interestingly, our results showed that 0.125% of agar gum and fucoidan to replace phosphate could enhance water‐holding capacity and maintain gel strength and textual properties of surimi products well. Especially at frozen storage for 1 year, 0.125% of agar gum reduced the expressible moisture content of surimi products by around 10% (p < .05). Sensory evaluation showed that 0.125% of agar gum and fucoidan instead of phosphate can improve tissue and fondness of surimi products in refrigerated storage for 24 h but not in frozen storage for 1 year. The addition of agar gum and fucoidan at a high concentration >0.50% increased the WHC, but significantly decreased gel strength and springiness of surimi products (p < .05). Particularly, 1.00% of agar gum and fucoidan reduced gel strength by around 20% (p < .05). It might be due to the destruction of the gel network structure of surimi protein following the excess addition of these polysaccharides. It can be concluded that 0.125% of agar gum and fucoidan can replace phosphate to develop high‐quality surimi products, and excessive addition of them have negative effects.

Effects of Enzymatic Konjac Glucomannan Hydrolysates on Textural Properties, Microstructure, and Water Distribution of Grass Carp Surimi Gels

This present work investigated the influence of konjac glucomannan (KGM) enzymatic hydrolysates on the textural properties, microstructure, and water distribution of surimi gel from grass carp (Ctenopharyngodon idellus). The molecular weight (M_w) of KGM enzymatic hydrolyzed by β-dextranase degraded from 149.03 kDa to 36.84 kDa with increasing enzymatic time. In the microstructure of surimi gels, KGM enzymatic hydrolysates with higher M_w showed entangled rigid-chains, while KGM enzymatic hydrolysates with lower M_w (36.84 kDa) exhibited swelled fragments. The hardness of surimi gel with a decline in KGM M_w exhibited first increasing then decreasing trends, while the whiteness of surimi gel increased. When KGM M_w decreased, the immobile water percentage of total signals decreased from 96.7% to 93.6%, and mobile water increased from 3.03% to 6.37%. In particular, the surimi gel with the addition of K2 showed better gel strength and water distributions. KGM enzymatic hydrolysates are expected to be used as a low-calorie healthy gel enhancer in surimi processing.