Effect of modified washing process on water usage, composition and gelling properties of grass carp surimi

BACKGROUND

Washing is an essential process in surimi production, from which a large amount of wastewater is generated. Due to the increasing pressure of environmental protection, it is an urgent technical requirement for surimi manufacturers to reduce water usage while maintaining the quality of surimi. In this study, composition, structure and gelling properties of grass carp surimi prepared with a modified washing process (MWP) were investigated. Intermediate dehydration with various compression ratios were utilized between two washing cycles.

RESULTS

Water usage and wastewater discharge were reduced significantly by 33% and 38%, respectively, when MWP was applied. As the compression ratio increased, composition of fat, cathepsins, transglutaminase and heme proteins in surimi decreased gradually. Yield, protein content and the major protein pattern of surimi were not changed, but surface hydrophobicity gradually decreased. As the compression rate increased to 1:2.0, textural values and water holding capacity of the corresponding surimi gel decreased gradually, while whiteness increased and then remained unchanged. At a higher compression ratio (>1:1.5), aggregated network and excessive free water were observed in the surimi gel. Composition and gelling properties of the MWP surimi with a compression ratio of 1:1.2-1:1.5 were equal to those of the surimi prepared under conventional three-cycle washing.

CONCLUSION

Results indicated that MWP demonstrated its great potential in surimi production by dramatically reducing the usage of cold water and discharge of wastewater without scarifying surimi quality. © 2022 Society of Chemical Industry.

Conformational Changes in Proteins Caused by High-Pressure Homogenization Promote Nanoparticle Formation in Natural Bone Aqueous Suspension

As a natural calcium resource, animal bone needs to be miniaturized to the nanoscale to improve palatability and absorption capacity. To explore the mechanism of high-pressure homogenization (HPH) in preparing natural bone aqueous nanosuspensions, the relationships between the changes in protein conformation, solubility and quality characteristics of rabbit bone aqueous suspensions (RBAS) prepared by different HPH cycles were studied. The results showed that the improvements in particle size, stability and calcium solubility of RBASs could be mainly attributed to the improvement of protein solubility induced by the changes in protein conformation. HPH treatment led to the denaturation and degradation of protein in rabbit bone, generating soluble peptides and improving the stability of the suspensions by enhancing the surface charge of the particles. When collagen as the main protein was partially degraded, the hydroxyapatite in the bone was crushed into tiny particles. The increase in the particle-specific surface area led to the release of calcium ions, which chelated with the peptides to produce peptide calcium. However, excessive HPH treatment caused the production of protein macromolecular aggregates and affected the quality of RBASs. This study is helpful to promote the application of HPH technology in animal bone nanoprocessing.

Synthesis of nano hydroxyapatite from Hypopthalmichthys molitrix (silver carp) bone waste by two different methods: a comparative biophysical and in vitro evaluation on osteoblast MG63 cell lines

More than a thousand tonnes of fish bone wastes can be transformed into biomedical products annually. Alkaline hydrolysis and thermal calcification were used to create nanosized hydroxyapatite (HAp) crystals from Silver carp bone wastes. Biophysical tests were used to determine the nano size and chemical composition of synthesised hydroxyapatite. Alkaline hydrolysis hydroxyapatite (AH-HAp) was 58.3 nm, while Thermal calcination hydroxyapatite (TC-HAp) was 64.3 nm in size, confirmed by Atomic Force Microscopy. Energy Dispersive X-ray Analysis studies showed Ca/P (Calcium phosphate) ratio of AH-HAp to be 1.65, whereas TC-HAp as 1.45, confirming AH-HAp to be organically rich along with a similar Ca/P ratio as natural HAp. Fourier Transform Infrared Spectroscopy spectra indicated HAp formation from both procedures, however AH-HAp had superior crystallinity than TC-HAp confirmed from X-Ray Diffraction spectra. MG63 osteoblast cell lines showed 91% cell viability in cytotoxicity studies and 70.1% proliferation efficiency in Alkaline Phosphatase assay, which was higher than TC-HAp. The present study shows that HAp produced via alkaline hydrolysis has better biocompatibility which enhances its applicability as a biomaterial, than HAp synthesized through thermal calcination, which tends to incinerate organic moieties.

Effects of Catfish (Ictalurus punctatus) Bone Powder on Consumers’ Liking, Emotions, and Purchase Intent of Fried Catfish Strips

Catfish are the predominant U.S. aquacultural product. However, byproducts from filleting, including bones that are high in calcium, typically go to waste or are sold as a low-valued feed. This research evaluated the potential use of catfish bone powder (CBP; 21.07% calcium) as a food ingredient. Catfish fillet strips were dredged with a breading mix (CBPM) containing 0% (0CBPM), 10% (10CBPM), and 20% (20CBPM) CBP before frying. Consumers (N = 211) evaluated sensory liking (nine-point hedonic scale) and attribute intensity (JAR scale), emotions (check-all-that-apply), and purchase intent (PI, yes/no) of samples. Color and texture were measured instrumentally. CBP did not show any negative effects on liking scores, although crispiness was scored higher for 20CBPM (mean = 6.88) than 10CBPM (mean = 6.43). Positive emotions were most relevant to CBP-containing samples, with significantly higher rates of adventurous and understanding. Information about calcium fortification using CBP increased PI to 81.04% for the 10CBPM and 83.89% for the 20CBPM samples and showed a greater effect on Latin Americans/Hispanics than U.S. Americans. Consumers were not averse to the consumption of CBP which can contribute to sustainable nutrition through waste reduction. Successful calcium fortification of fried catfish dredged with 20% CBP did not compromise sensory liking and may be feasible in other products.

Recent developments in maintaining gel properties of surimi products under reduced salt conditions and use of additives

Salt is a necessary condition to produce a surimi product that is based on the gelation of salt-soluble myofibrillar proteins. Recently, there has been a growing concern among consumers to consume healthy foods due to the threat of several chronic diseases caused by an unhealthy diet. Methods of reducing salt content out of concern for health issues caused by excessive sodium intake may affect the gel properties of surimi, as can many health-oriented food additives. Several studies have investigated different strategies to improve the health characteristics of surimi products without decreasing gel properties. This review reports recent developments in this area and how the gel properties were successfully maintained under reduced-salt conditions and the use of additives. This review of recent studies presents a great deal of progress made in the health benefits of surimi and can be used as a reference for further development in the surimi product processing industry.

Textural, Sensory, and Chemical Characteristic of Threadfin Bream (Nemipterus sp.) Surimi Gel Fortified with Bio-Calcium from Bone of Asian Sea Bass (Lates calcarifer)

The effects of Asian sea bass (Lates calcarifer) bio-calcium (ASBB) at different levels (0, 2, 4, 6, 8, and 10%) (w/w) on properties of threadfin bream (Nemipterus sp.) surimi gel were investigated. ASBB addition increased breaking force and deformation, while reduced expressible moisture content (p < 0.05) of surimi gel. L* (lightness), a* (redness), and b* (yellowness) values were increased with augmenting ASBB levels; however, whiteness slightly decreased in surimi gel incorporated with ASBB (p < 0.05). Higher likeness scores were noticed in surimi gel containing ASBB, compared to that of the control. However, a slight decrease in the likeness score was noticed in surimi gel with 10% (w/w) ASBB (p < 0.05). Surimi gel added with 8% (w/w) ASBB possessed the increase in breaking force by 80% from the control and had the highest likeness score. Texture profile analysis of surimi gel added with ASBB showed the improved texture characteristics with coincidentally higher storage modulus of surimi paste. Surimi gel with 8% (w/w) ASBB had a denser and finer microstructure with higher ash, calcium, and phosphorous contents, compared to the control. Thus, incorporation of bio-calcium up to 8% (w/w) not only increased mineral content, but also improved textural, sensory, and microstructural properties of surimi gel.

Quality characteristics of fortified silver carp surimi with soluble dietary fiber: Effect of apple pectin and konjac glucomannan

The study focused on assessing quality parameters of the surimi incorporated with soluble dietary fibers apple pectin and konjac glucomannan at different levels. The results showed that apple pectin at 0.025% and konjac glucomannan at a 2% level exhibited improved gel-forming ability significantly (p < 0.05). SDS- PAGE revealed high molecular weight protein crosslinks in apple pectin treated surimi gels and disappearance of myosin bands in konjac glucomannan treated surimi gels. The water holding capacity of surimi was the highest when 0.075 g/100 g of apple pectin was added. Konjac glucomannan treated gels exhibited superior whiteness values. The analysis of soluble protein revealed that hydrophobic bonds increased in both the treatments. The hardness values of pectin gels enhanced as the level increased. Other TPA parameters are shown an inconsistent trend. It can be demonstrated that the incorporation of apple pectin and konjac glucomannan at a level of 0.025 and 2.0% may be a novel strategy to improve the gel strength of the surimi.

Assessing gel properties of Amur sturgeon (Acipenser schrenckii) surimi prepared by high-temperature setting (40 °C) for different durations

BACKGROUND

Setting effects are different for each fish species tested. There is no published literature on the response of Amur sturgeon (Acipenser schrenckii) to increased setting times. This study investigated the effects of high-temperature setting (40 °C) for different durations on the gel properties of A. schrenckii surimi. As A. schrenckii is a new surimi material, it is also necessary to conduct a sensory evaluation and to report the surimi yields.

RESULTS

Increasing setting durations (0.5-1.5 h) significantly improved the gel properties. The best results in terms of molecular forces, gel strength, texture profile analysis (TPA), water holding capacity (WHC), and whiteness were obtained by the gels with setting durations of 1 and 1.5 h. The protein degradation detected as a result of extended setting durations (>2 h) significantly decreased the gel properties. The most inferior gel properties were shown by the gel with setting for 3 h. Protein degradation also resulted in higher cooking loss and poor microstructures. The sensory evaluation indicated that A. schrenckii surimi was generally accepted by the panelists in terms of color, texture, and aroma. The surimi yield obtained in this study was 32.4%, which was similar to commercial surimi and higher than several surimi yields in recent studies.

CONCLUSION

Setting durations from 0.5 to 1.5 h can be implemented to improve the properties of A. schrenckii surimi. Extended durations (>2 h) must be avoided. Overall, this work provided some necessary information about setting response, gel properties, sensory evaluation, and surimi yield in A. schrenckii, which will be useful for further studies. © 2020 Society of Chemical Industry.

Effects of Vacuum Freeze-Drying and Vacuum Spray-Drying on Biochemical Properties and Functionalities of Myofibrillar Proteins from Silver Carp

Fish protein powders were produced from silver carp myofibrillar proteins using vacuum freeze-drying and vacuum spray-drying. Biochemical properties and functionalities of freeze-dried and spray-dried powders were determined. The myofibrillar proteins were partially denatured under both the drying methods which were evidenced by the increase of free sulfhydryl content, surface hydrophobicity, and intrinsic fluorescence while the decrease of the Ca2+-ATPase activity and percentage of theα-helical structure. With respect to vacuum freeze-drying, the proteins were denatured to a higher degree by vacuum spray-drying. The spray-dried fish protein powder showed a higher water retention capacity and emulsifying stability index, but the same solubility and emulsifying activity index. The micrographs indicate that vacuum freeze-dried powder formed a spongy structure, while the powder under vacuum spray-drying mostly appeared spherical in shape with hollow inside. Thus, the two drying methods can be used to manufacture fish protein powders with varied molecular structures and functionalities.

Gelling properties of silver carp surimi as affected by different comminution methods: blending and shearing

BACKGROUND

Blending and shearing, two types of comminution methods, are widely used in the manufacturing of surimi-based products. The comminution methods applied are varied to product types and manufacturers. In this study effects of different comminution methods (blending and shearing) on gelling properties of silver carp surimi were investigated.

RESULTS

Regardless of comminution methods, breaking force, penetration distance and water holding capacity of surimi gel significantly increased with comminution duration up to 10 min. As compared with blending, those values under shearing of the same duration were significantly higher. Within 3 min of comminuting whiteness values of gels by shearing were significantly higher than those by blending. Electrophoresis studies showed that comminution method had no obvious effect on protein patterns. Scanning electron microscopy images revealed that more uniform and denser network was formed in the surimi gels made by shearing. Water distribution of the gels made by shearing was obviously more uniform according to magnetic resonance imaging analysis.

CONCLUSION

Our results suggested that with respect to blending, shearing was a better choice to maximize the gelling ability of silver carp surimi, which resulted in the higher values of texture, whiteness and water holding capacity. It could be attributed to the denser three-dimensional network and more uniform water distribution of the surimi gel prepared by shearing. © 2019 Society of Chemical Industry.