Surimi Products Research Articles

Effect of material temperatures on quality of fish vermicelli, a noodle-shaped surimi product.

The study investigated the effect of material temperatures (15°C, 20°C, 25°C, 30°C, 35°C, and 40°C) on the quality of fish vermicelli (FV) in terms of morphological, cooking, textural, microstructural, and water distribution properties. Results showed that as the material temperatures increased, the surface smoothness, cooking characteristics, and textural properties of FV significantly increased, followed by a decrease. Especially, when the material temperatures were 25°C and 30°C, the FV samples exhibited denser and more continuous gel networks with more embedded starch particles, resulting in decreased cooking loss and improved tensile strength. However, at material temperatures above 35°C, the continuity of the protein phase was disrupted by overswelling starch granules, leading to the worst cooking characteristics and textural properties. Especially at material temperatures of 40°C, the water holding capacity, hardness, and springiness of FV decreased by 25.59%, 73.48%, and 47.98%, respectively, compared to the samples at 25°C. Additionally, the cooking loss increased by 91.40%. In conclusion, the critical material temperature for the quality deterioration of FV was 35°C, and it was recommended to produce FV below this temperature.

Controlled release of fishy odors in soluble dietary fiber/surimi mixture by kinetic analysis of real and simulated systems

This study aimed to investigate the effects and mechanisms of soluble dietary fiber (SDF), temperature and hydrophobicity on the release of fishy compounds from surimi by the preparation of real and simulated systems. The results of gas chromatography-mass spectrometry revealed 15 fishy compounds in silver carp surimi, and adding 2 wt% SDF to surimi was found to inhibit the release of 14 fishy compounds by 2.16–43.49%. The simulated release indicated that SDF matrices with different concentrations inhibited the release of fishy compounds by different mechanisms. The resistance to the release of fishy compounds was attributed to viscosity and chemisorption in 2 and 5 wt% SDF matrices, while chemisorption and entanglement network in 8 and 10 wt% SDF matrices. Moreover, high temperature and hydrophobicity of fishy compounds could promote their release by decreasing interfacial mass transfer resistance and H-bond interaction, respectively. Additionally, adding SDF changed the release pathway of fishy compounds in surimi, and they were released through the first pathway consisting of surimi intraparticle diffusion, SDF boundary layer diffusion and gas-liquid interfacial diffusion, or through the second pathway additionally including chemisorption and desorption. This study provides new insights into controlling the release of fishy odors in surimi products.

Effect of cellulose on gel properties of heat-induced low-salt surimi gels: Physicochemical characteristics, water distribution and microstructure.

The processing of surimi products requires the addition of high levels of salt, which makes it a high-salt food that poses a risk to human health. The search for exogenous additives to reduce the salt content of surimi products while ensuring their quality characteristics is crucial. Therefore, the effect of different species of cellulose on enhancing the quality characteristics of low-salt surimi gels was investigated and the best-modified cellulose was identified. Carboxymethyl cellulose (CMC), hydroxypropyl methylcellulose (HPMC), and microcrystalline cellulose (MCC) were selected for this study to compare with high-salt control and low-salt control. The results showed that cellulose could induce conformational transitions of proteins and promote the formation of an ordered and dense surimi gel network and the minimum porosity of 15.935% was obtained in the MCC-treated group. The cellulose-treated group conferred good textural properties to the surimi gels, significantly improved gel strength and water retention capacity (p < 0.05), and reduced the amount of water lost after cooking treatment (p < 0.05). Low-field NMR results showed that cellulose reduced the release of water, converting more free water to immobile water, thus increasing the water proton density. The higher energy storage modulus G' in the presence of cellulose indicated a more stable surimi gel system dominated by springiness. In summary, cellulose could confer better quality characteristics to low-salt surimi gels and MCC performance was superior to other cellulose species. This study helps the understanding of the mechanism of cellulose-surimi action on the development of high-quality low-salt surimi gels.

Classification of Quality Characteristics of Surimi Gels from Different Species Using Images and Convolutional Neural Network

In the aspect of food quality measurement, the application of image analysis has emerged as a powerful and versatile tool, enabling a highly accurate and efficient automated recognition and the quality classification of visual data. This study examines the feasibility of employing an AI algorithm on labeled images as a non-destructive method to classify surimi gels. Gels were made with different moisture (76–82%) and corn starch (5–16%) levels from Alaska pollock and Threadfin breams. In surimi gelation, interactions among surimi, starch, and moisture caused color and quality shifts. Color changes are indicative of structural and quality variations in surimi. Traditional color measuring techniques using colorimeter showed insignificant differences (p &lt; 0.05) in color values and whiteness among treatments. This complexity hindered effective grading, especially in intricate formulations. Despite insignificant color differences, they signify structural changes. The Convolutional Neural Network (CNN) predicts the visual impact of moisture and starch on gel attributes prepared with different surimi species. Automated machine learning assesses AI algorithms; and CNN’s 70:30 training/validation ratio involves 400–700 images per category. CNN’s architecture, including input, convolutional, normalization, Rectified Linear Unit (ReLU) activation, and max-pooling layers, detects subtle structural changes in treated images. Model test accuracies exceed 95%, validating CNN’s precision in species and moisture classification. It excels in starch concentrations, yielding &gt; 90% accuracy. Average precision (&gt;0.9395), recall (&gt;0.8738), and F1-score (&gt;0.8731) highlight CNN’s high performance. This study demonstrates CNN’s value in non-destructively classifying surimi gels with varying moisture and starch contents across species, and it provides a solid foundation for advancing our understanding of surimi production processes and their optimization in the pursuit of high-quality surimi products.

Microbial transglutaminase promotes cross-linking for enhancing gelation of myofibrillar protein in frozen Litopenaeus vannamei through deamination reaction

In this paper, the effects of different microbial transglutaminase (mTGase) treatments (0–0.5% w/w) on the structural and functional characteristics of frozen shrimp (Litopenaeus vannamei) were investigated to explore the changes in myofibrillar protein (MP) during the catalytic process of mTGase, and further enhance the gel properties of shrimp surimi products. Fourier transform infrared spectroscopy showed that mTGase treatment caused a shift from α-helix to β-turn and β-sheet in the secondary structure of the protein, while chemical force results indicated that moderate addition of enzyme could promote the formation of disulfide bonds in the gel system, contributing to the formation of a stable three-dimensional spatial structure. These structural changes led to a significant increase in gel strength, WHC and storage modulus (G′) after mTGase-induced protein gelation, resulting in an increase in the solid properties of the gel; and the relaxation time T22 was significantly shortened, indicating a gradual decrease in water freedom in the protein gel network. In addition, scanning electron microscopy results showed that the gel with 0.4% mTGase had a denser network structure and more uniform pores. Simultaneously, mTGase facilitated the reduction of free amino groups through deamination reaction, resulting in an elevated cross-linking degree and a reduced hydrolysis rate of pepsin. The above results indicated that appropriate mTGase treatment could improve the structure and functional properties of shrimp, benefit the quality of shrimp surimi products, and provide some references for the highly processed frozen Litopenaeus vannamei.

Effects of the soy protein to wheat gluten ratio on the physicochemical and structural properties of Alaska pollock surimi-based meat analogs by high moisture extrusion

Surimi products have attracted much attention and are widely used in the food industry. Currently, the processing and exploitation of surimi products are mostly based on their gel characteristics. However, the abundant protein in surimi can be rearranged and integrated by high-temperature melting to generate a new surimi product with fibrous structures. In this study, meat analogs (new surimi product) were produced by high moisture extrusion (HME) using Alaska pollock surimi and plant protein (8:2), where the plant protein consisted of different ratios of soy protein and wheat gluten (9:1, 7:3, 5:5, 3:7 and 1:9). The product was marked as SSG because it was composed of Alaska pollock surimi, soy protein and wheat gluten. The structure and color results showed that the hardness and ΔE of SSG decreased, while the fibrous degree and lightness increased with increasing WG content. The observation of the macrostructure and microstructure also showed that the skeleton structure of SSG was more obvious with increasing WG addition, but the viscosity reflected a decreasing trend. Furthermore, an increase in the WG content raised the free water ratio and the total content of β-sheets, whereas the appropriate plant protein ratio reduced the SSG's thermal stability. In conclusion, Alaskan pollock surimi and the appropriate proportion of plant protein can form structurally stable meat analogs by high moisture extrusion.

High internal phase emulsions of ω-3 fatty acids stabilized by fish scale gelatin particles: Application to lipid-enhanced surimi 3D printing

This study explores the use of exogenous lipid fortification and 3D printing technologies in the production of innovative surimi products. Specifically, the study focuses on stabilizing high internal phase emulsions (HIPEs) rich in polyunsaturated fatty acids using microbial transglutaminase (MTGase) cross-linked fish scale gelatin particles (FSG). The addition of FSG significantly increased the HIPEs' thermal and freeze-thaw stability. Confocal laser scanning microscopy (CLSM) demonstrated that cross-linking between FSG particles further stabilized the network structure of the HIPEs. An attempt was made to prepare food inks for 3D printing by incorporating the obtained HIPEs into surimi to investigate the effects of HIPEs on the mechanical properties, rheological behavior, moisture distribution and printing performance of HIPEs-surimi system. The mechanical properties of surimi were enhanced by including HIPEs, which allowed for finer print nozzles (1.2 mm) and produced finer textures. The incorporation of HIPEs in surimi products resulted in an increase in the amount of healthy lipids, which is beneficial for meeting the nutritional needs of consumers and addressing the technical challenges in producing high-end surimi products.

Comparison of volatile aroma compounds in commercial surimi and their products from freshwater fish and marine fish and aroma fingerprints establishment based on metabolomics analysis methods

Understanding the differences in odors of freshwater and marine fish surimi and their products is important for the quality control of surimi products. Aroma compounds in silver carp surimi and three kinds of marine fish surimi and their products were identified by gas chromatography-mass spectrometry/olfactometry, and aroma fingerprints of them were established based on metabolomics analysis methods. Silver carp surimi and surimi products showed the highest “fresh fish” and “grassy, earthy” notes, while the marine fish surimi and their products presented a strong “sea breeze-like” odor. Five Br-containing compounds (sea breeze-like) were identified in the marine fish samples. The aroma fingerprints showed that the odor compositions of freshwater and marine surimi/surimi products were divided into two categories, and the marine fish surimi and their products also showed differences in odors. Furthermore, four commercial surimi and their products could be distinguished according to 33 and 28 differential aroma components, respectively.

Effects of AAPH on structure, allergenicity and physicochemical properties of shrimp myofibrillar protein

Lipid peroxidation has been shown to associate with meat quality by affecting physicochemical properties of myofibrillar proteins. In this work, shrimp myofibrillar protein (MP) was oxidized using 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH), which could generate peroxyl radicals in lipid peroxidation. Results showed that increasing AAPH concentration led to an increase in carbonyl groups and a decrease in free amino and sulfhydryl thiol groups in MP. Secondary structural analysis of MP revealed a conversion of α-helix to β-sheet content after AAPH treatment. SDS-PAGE showed the band intensity of tropomyosin was reduced after AAPH treatment, indicating a reduced allergenicity of tropomyosin. Moderate oxidation (1–10 mmol/L AAPH) promoted the formation of a dense network of MP gel, resulting in enhanced textural and rheological properties. However, excessive oxidation (10–20 mmol/L AAPH) weakened the MP gel strength and decreased its water-holding capacity. These findings provide theoretical guidance for developing shrimp surimi products with desirable textures.

Investigation of the relationship between gel strength and microstructure of surimi gel induced by dense phase carbon dioxide based on quantitative analysis

The microstructure of a surimi product determines its quality. Dense phase carbon dioxide (DPCD) can induce surimi gel formation, and the gel strength of the product are significantly better than that of heat-induced gels. The study analysed the changes of the surimi from golden pompano gel strength during the process of DPCD-induced gelation, and the changes of microstructure based on quantitative analysis of scanning electron microscope (SEM) image using ImageJ 1.42 software. The correlations between gel strength and microstructure was investigated. The results showed that the DPCD treatment significantly increased the cross-linking degree (CLD) and gel strength of surimi, compared with the raw surimi. The CLD and gel strength of surimi increased with the increase of DPCD treatment pressure, temperature and time. Quantitative microscopic analysis revealed that the number of pores (n) in the surimi gels increased and then decreased. The apparent porosity (ƞa), average pore area (Aa), average pore perimeter (Pa), fractal dimension (Df) and pore equivalent diameter (d) increased with the increase of DPCD treatment pressure, temperature and time. Correlation analysis showed that the CLD, ƞa, Aa, Pa, Df, d and median pore perimeter (Pc-50) were strongly positively correlated with the gel strength. In contrast, lacunarity (L) is strongly negatively correlated with the gel strength. The linear correlation coefficients between the CLD, ƞa and Df and the gel strength are 0.97, 0.95 and 0.96, respectively. These results provide a technical basis for DPCD to process high-quality surimi products. These findings also offer a novel approach for the testing and evaluating of the quality of surimi products.

Gelation characteristics of partially purified myofibrillar proteins extracted from commercially harvested Indian mackerel and threadfin bream.

Gelling behaviors of partially purified myofibrillar proteins (PPMP) extracted from Indian mackerel (IM) and threadfin bream (TB) as a function of heating temperatures (20-75°C) were comparatively studied. PPMP obtained from IM (IM-MP) showed lower turbidity and surface hydrophobicity as compared to those extracted from TB (TB-MP). Moreover, lower disulfide bond content was noticed in IM-MP (7.7-9.46mol/106 g protein) as compared to TB-MP (10.99-13.95mol/106 g protein) during the heating process. There was no major difference in the amino acid profile noticed between PPMP from both the species, except lysine and glutamine contents, which were higher in TB-MP. Structural analysis, FTIR spectra, amide I band, and fluorescence intensity substantiated those changes. The protein pattern also revealed autolysis of IM-MP. The transmission analysis also showed lower aggregation and crosslinking ability of IM-MP than TB-MP. Therefore, poorer gelling behavior of IM-MP reconfirmed the inferior gel property of surimi gel from IM to gel from TB. Potential development is still required for the improvement of the gel properties of dark-fleshed fish surimi such as IM. PRACTICAL APPLICATION: Indian mackerel (IM) is an abundant and widely captured fish species. Due to overexploitation of lean fish, pelagic fish could be explored as a potential raw material for surimi production. However, poor gelling properties of IM limit its use in the surimi industry. This study provides an insight into the gelling behavior of myofibrillar proteins from IM during the gelation process in comparison with the lean fish (threadfin bream). Overall, structural and rheological changes of myofibrillar proteins play a role in gelation, thus affecting gel properties between two species. Further improvement of the gel of IM is still required.

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.

Impact of Washing with Antioxidant-Infused Soda-Saline Solution on Gel Functionality of Mackerel (Auxis thazard) Surimi.

Mackerel (Auxis thazard), a tropical dark-fleshed fish, has the potential to be used in the production of surimi. It is necessary to identify the optimal washing method to make better use of this species since efficient washing is the most important step in surimi processing to ensure maximal gelling and high-quality surimi. The purpose of this study was to evaluate the combined effect of cold carbonated water (CW) with NaCl and antioxidants in washing media, so-called antioxidant-infused soda-saline solution, on lipid and myoglobin removal efficacy, biochemical characteristics, gelling properties, sensory features, and the oxidative stability of mackerel surimi in comparison with unwashed mince (T1) and conventional water washed surimi (T2). Mackerel mince was washed with CW in the presence of 0.6% NaCl at a medium to mince ratio of 3:1 (v/w) without antioxidant (T3) or with the addition of 1.5 mM EDTA plus 0.2% (w/v) sodium erythorbate and 0.2% sodium tripolyphosphate (T4), 100 mg/L gallic acid (T5), and 5 mM citric acid containing 8 mM calcium chloride (T6). During the first washing cycle, the antioxidants were mixed into the washing medium. The second and third washing cycles were then completed with cold water. The yields of all treatments were roughly 75-83%, based on the gross weight of the raw mince. The pH of the surimi was in a range of 5.47-6.46. All of the surimi had higher reactive sulfhydryl (SH) content and surface hydrophobicity but lower Ca2+-ATPase activity than unwashed mince (p < 0.05). After washing, lipids decreased significantly (p < 0.05), accounted for a 65-76% reduction. The T2 surimi had the highest peroxide value (PV). T1 had the lowest conjugated diene value. T1 and T4 surimi had the lowest TBARS value (p < 0.05). A lower non-heme iron level was found in all antioxidant-treated samples than in T1. Washing can increase the redox stability of myoglobin regardless of the washing media, as seen by the relatively low metmyoglobin levels. According to the dynamic viscoelastic behavior, all surimi and unwashed mince underwent the same degree of sol-gel transition following heat gelation. T1 showed the lowest breaking force, deformation, gel strength, and whiteness (p < 0.05). Surimi made from T4 or T5 had the highest gel strength when both breaking and deformation were considered, but the latter's expressible drip was noticeably higher. Surimi gel appears to be stabilized against lipid oxidation, as demonstrated by low PV and TBARS levels, when produced with T4. Because of the low level of TBARS, all 10 panelists rated rancid odor as low (~1 out of 4), with no significant variations across treatments. Only treatments with T4 and T6 tended to have a lower fishy odor score as compared to unwashed mince. Scanning electron microscope demonstrated that surimi gels washed with all washing media exhibited microstructures that were very comparable, with the exception of the T6 treatment, which had big pores and aggregates. Based on the quality features, T4 appeared to be the optimal medium to enhance the gel functionality of mackerel surimi.

Effect of pressure-shift freezing treatment on gelling and structural properties of grass carp surimi

The damage of conventional freezing (CF) to the quality of surimi products is an urgent problem in the food industry. In the study, the effect of different freezing treatments [CF, pressure shift freezing (PSF), pressure-shift freezing pretreatment (Pr-PSF), unfrozen control] on gelling properties [gel strength, texture profile analysis (TPA), color], water-holding capacity (WHC) and protein structure characteristics of the grass carp surimi gel were evaluated and compared. Compared with other freezing treatment groups, surimi gel strength was increased three to four times after PSF treatment, which was mainly caused by the change in the microstructure and the WHC of the surimi gel. The study showed that PSF treatment could significantly improve the quality of the surimi gel and overcome the negative effect of freezing on the surimi gel. This indicates that PSF technology has a wide application prospect in the surimi gel processing industry, food processing and related material fields.Industrial relevance: PSF can enhance the commodity value of low-value freshwater fish products and has potential in surimi gel new product development. The development of new products and the use of new resources are very important in addressing the global food crisis and resource shortages. In addition, PSF units with self-cooling systems offer opportunities for scale-up and commercialization.

Investigation of the changes in gelation properties of hydroxypropyl distarch phosphate-surimi gel under different gelation-freezing treatments.

Frozen storage often leads to quality deterioration of surimi-based products. At present, most of the research focuses on improving the quality of surimi products by adding cryoprotectants, and there are few studies available on preparation technology. Therefore, the effects of different gelation-freezing treatments, high temperature heating-freezing treatment (HF), low temperature heating-high temperature heating-freezing treatment (LHF) and low temperature heating-freezing-high temperature heating treatment (LFH) on the quality changes of surimi gels containing hydroxypropyl distarch phosphate (HPDSP) during frozen storage were investigated. With the extension of frozen storage time, the quality of surimi gel in all groups decreased, but the quality of surimi gel with HPDSP was better than that of surimi gel without HPDSP. Compared with HF and LHF, the change range of breaking force, hardness, gumminess, whiteness and disulfide bond content of HPDSP-surimi gel treated with LFH was the least during the frozen storage. In the reheating process of LFH, HPDSP could absorb the water lost during freezing. Therefore, the change in the transverse relaxation time of HPDSP-surimi gels treated with LFH was smaller, with more immobile water and less free water and P22 of 96.81% and P23 of 0% at 16 weeks. In addition, the breaking deformation, cohesiveness, resilience, springiness and protein composition of surimi gels with and without HPDSP treated with HF, LHF and LFH did not change significantly during frozen storage. The combination of LFH and HPDSP could effectively reduce the quality change of surimi gel during frozen storage. © 2023 Society of Chemical Industry.

L-lysine modified whey protein isolate: Mechanism on the improvement of the gel properties and its application as model fish sausage

In this study, whey protein isolate (WPI) was used as raw material to study the effects of l-lysine (Lys) on the gel properties and structure of WPI, and the application of modified WPI in fish sausage was studied. The results showed that with the increase of Lys concentration, the gel properties and water holding capacity of WPI were greatly improved, while the Lys concentration exceeding 4 mg/mL would produce adverse reactions, such as the decrease of chromaticity and gel hardness. At Lys concentration of 1.6 mg/mL, WPI showed the highest texture properties and good water holding capacity, which depended on the dense microstructure and reduced pore size. This was because WPI crosslinks with Lys through electrostatic interaction, reducing electrostatic repulsion and promoting its crosslinking and polymerization, which was manifested by the change of WPI structure and the increase of particle size. In addition, the hardness, chewiness, and cooking loss capacity of the surimi added with modified WPI were better than those of the pure fish sausage, corn starch and WPI single treatment group. This study can provide a theoretical basis for the study of WPI modified gel and provide guidance for the modified WPI used as gelling agent in surimi products.

High inner phase emulsion of fish oil stabilized with rutin-grass carp (Ctenopharyngodon idella) myofibrillar protein: Application as a fat substitute in surimi gel

This study investigated the effect of rutin-grass carp myofibrillar protein (R-GMP) co-stable fish oil high internal phase emulsion on the quality of surimi gel compared with the direct addition of soybean oil. Combined with the stability, microstructure and rheological properties, R-GMP (GMP: 3.0%, rutin: 12%,/GMP, w/w) could form a stable O/W type high internal phase Pickering emulsion with an oil-water ratio of 0.75. The L*, a*, and b* values and whiteness of silver carp surimi gel were increased significantly (P < 0.05) after fish oil-based high internal phase emulsion was added as oil. Meanwhile, compared with the direct addition of soybean oil, the hardness, chewiness, gel strength and water-holding capacity of surimi gel were significantly enhanced (P < 0.05) after the addition of R-GMP high internal phase emulsion, and more free water was bound to the gel network. The microstructure showed that the R-GMP high internal phase emulsion could be evenly distributed in the dense and ordered protein network gel in the form of small oil droplets, while the direct addition of soybean oil would produce an aggregation of oil droplets and destroy the network structure of the gel. In conclusion, R-GMP stabilized fish oil high internal phase emulsion optimizes the gel quality of oil-enhanced surimi gel, providing new ideas for healthy fat replacement and the development of functional emulsified surimi products.

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.

Yield and Technological Quality of Pirarucu Trimming Surimi According to the Number of Washing Cycles, Rice Flour Content, and Cooking Temperature.

This research aimed to optimize surimi production with innovative raw materials called pirarucu trimmings and broken rice grains, which are by-products from food industries. The effects of three independent variables (number of washing cycles, content, and cooking temperature of rice flour-RF) on surimi's physical, chemical, and technological qualities were investigated through a Box-Behnken design. The number of washing cycles affected yield (77-93%), moisture (55-67%), lipids (18-35%), protein (7.15-11.88%), whiteness (46.73-64.45), chroma (8.86-13.18), hue angle (80.79-93.12°), cohesiveness (0.40-0.61), springiness (0.51-0.99), and freeze stability after 4 weeks (85.16-96.53%). RF concentration affected moisture, lipids, cohesiveness, springiness, and freeze-thaw stability after 4 weeks. RF cooking temperature affected moisture, chroma, cohesiveness, and springiness. The optimal conditions for surimi production with high yield and overall quality were three washing cycles, 6% of RF, and RF cooking temperature at 85 °C. It reveals the promising potential of both by-products to be used as an ingredient in restructured products and contribute to improving agri-industry sustainability.

Effect of red algae powder on gel properties and in vitro hypolipidemic activity of fish balls

In this study, gel properties and in vitro hypolipidemic activity of fish balls with red algae powder including Porphyra and Bangia fusco-purpurea powder were investigated after frozen storage for 7 d. Water holding capacity and gel structure are important factors affecting the quality of minced fish products. The results showed that Porphyra powder at 0.5 % significantly increased water holding capacity of fish balls while Bangia fusco-purpurea powder not (p ≥ 0.05), and both Porphyra and Bangia fusco-purpurea powder enhanced protein interactions, the cross-linking of actin and gel network structure, but 1.0 % of them decreased water holding capacity, resulting the loose and irregular gel structure of fish balls with excessive aggregation partially (p < 0.05). Moreover, both Porphyra and Bangia fusco-purpurea powder higher than 0.5 % could significantly improve the bile salt binding ability of fish balls (p < 0.05), especially Bangia fusco-purpurea powder at 1.0 % also significantly increased the inhibition rate of pancreatic lipase of fish balls (p < 0.05), suggesting the enhanced hypolipidemic activity for fish balls with red algae powder. These findings indicated that surimi products with desirable gel and hypolipidemic activity can be designed by adding appropriate type and concentration of red algae powder.