Water Binding Capacity Research Articles

Low-Field NMR Analyses of Gels and Starch-Stabilized Emulsions with Modified Potato Starches

Many different biopolymers are used to stabilize emulsions, of which starch is of particular concern. To improve the characteristics and technical utility of native starch, various types of changes can be made. This article is a report describing the molecular dynamics of water by the low-field nuclear magnetic resonance (LF NMR) of chemically (E 1412 and E 1420) and physically modified starch (LU 1432) gels and the effect of their use on the stability of oil/water emulsions obtained using bovine and porcine fats. The analysis of changes in spin–spin and spin–lattice relaxation times over time showed that the presence of the type of starch modification significantly affects the values of T1 and T2 relaxation times, as well as the correlation times. Research on time-related changes in water binding in oil-in-water emulsions showed that potato starch modified by chemical methods can be used as an emulsifier. Compared to physically modified starch, chemically modified starches have a much better water-binding capacity.

Изучение органолептических и физико-химических свойств сыровяленых продуктов из мяса кролика

Aim. Study of the organoleptic, physical and chemical indicators of dry-cured snacks from rabbit meat using the Glimalask food additive. Materials and Methods. In the course of the research, standardized methods of analysis were used. The object of the study were two samples of products - dry-cured meat snacks from rabbit meat, produced according to the traditional technology of dry-cured meat products according to the developed recipes. For the development of laboratory samples, a marinade based on soy sauce, water and a complex of spices was used, while the Glimalask food additive (TС 2639-182-10514645-12) was additionally introduced into the experimental sample. To identify the indicators, standardized analysis methods were used: pH was determined according to GOST R 51478-99, water-binding capacity, water activity index, total moisture content – by drying, protein – by the Kjeldahl method and fat – by extraction method. The organoleptic evaluation of the obtained snacks was carried out using a nine-point scale in accordance with GOST 9959-2015. Results. Organoleptic evaluation: appearance, juiciness, consistency, color and taste, of the studied samples was carried out after drying. Thus, the prototype sample was rated higher than the control one, this is due to the use of the Glimalask food additive, which provided brighter taste and aroma characteristics and increased the juiciness of the snacks after the completion of the heat treatment. Next, the physicochemical parameters of the developed products were studied. It was revealed that in the test sample there was an increased protein content – more by 1.1%, moisture was less by 0.7% compared to the control, and the test sample of snacks was characterized by a high yield. Conclusion. Based on the results of the studies, it can be concluded that the use of the Glimalask food additive in the marinade recipe for the manufacture of dry-cured snacks did not have a negative impact on the finished product and contributed to the improvement of the taste, aroma and consistency of the finished products. The developed product has high consumer characteristics, meets the task of expanding the range of rabbit meat products. At the same time, the continuation of developments in this direction is of scientific and practical interest.

Extraction and characterization of chitin and chitosan from Nile tilapia scale in Lake Chamo, Arba Minch and their application in clarification of apple juice

AbstractFish and seafood processing industries generate large quantities of waste, which are at the origin of several environmental, economic and social problems. However, fish waste contains high value‐added substances such as collagen, gelatin, chitin and chitosan. In Ethiopia, Arba Minch is one of the leading areas of fish production zone, and hence, everyday lot of fish waste has been generated due to this. This work has focused on the extraction and characterization of chitin and chitosan from fish wastes (Nile tilapia). The chitin and chitosan extracted were characterized by analyzing parameters such as percentage yield, moisture and ash content, solubility, degree of deacetylation, water binding capacity, fat binding capacity, intrinsic viscosity and Molecular weight (Mw). The results obtained from this study show that the yield of chitin and chitosan was 29.88 ± 0.01% and 15.87 ± 0.14%, respectively. The moisture and ash content, DD, solubility, FBC, WBC, intrinsic viscosity and Mw of the extracted chitosan were found to be 6.79 ± 0.40%, 1.22 ± 0.16%, 85.25 ± 0.28%, 94.3 ± 0.99%, 391.17 ± 0.13%, 461.34 ± 0.42%, 6.832 ± 0.0101 and 3514.730 ± 1.1 g/mol, respectively. The chitosan was then employed for apple juice clarification and the reduction in total soluble solids value from (12.67 to 9.20), titratable acidity (2.38 to 1.61) and turbidity (320.2 to 86.6) after treatments have confirmed their effectiveness on apple juice clarification. The reduction in titratable acidity has been supported by increase in pH value (3.19 to 4.29). The sensory evaluation of control juice and chitosan‐added juice samples was performed, and it has been observed that chitosan concentration of up to 0.25 g/L was well accepted by the consumers.Novelty impact statement The current study is the first kind of attempt to analyze the different physicochemical properties of chitin and chitosan obtained from Nile tilapia fish scale wastes, from Lake Chamo, Arba Minch. It also throws light on how fish scale wastes can be converted into useful products like chitin and chitosan. The application of extracted chitosan in apple juice clarification has been successfully demonstrated in the study.

Cellulose Fibre Degradation in Cellulose/Steel Hybrid Geotextiles under Outdoor Weathering Conditions.

Risks from rockfall and land sliding can be controlled by high-tensile steel nets and meshes which stabilise critical areas. In many cases, a recultivation of the land is also desired. However, high-tensile steel meshes alone are not always sufficient, depending on the location and the inclination of the stabilised slope, to achieve rapid greening. Cellulose fibres exhibit high water binding capacity which supports plant growth. In this work, a hybrid structure consisting of a nonwoven cellulose fibre web and a steel mesh was produced and tested under outdoor conditions over a period of 61 weeks. The cellulose fibres are intended to support plant growth and soil fixation, and thus the biodegradation of the structure is highly relevant, as these fibres will become part of the soil and must be biodegradable. The biodegradation of the cellulose fibres over the period of outdoor testing was monitored by microscopy and analytical methods. The enzymatic degradation of the cellulose fibres led to a reduction in the average degree of polymerisation and also a reduction in the moisture content, as polymer chain hydrolysis occurs more rapidly in the amorphous regions of the fibres. FTIR analysis and determination of carboxylic group content did not indicate substantial changes in the remaining parts of the cellulose fibre. Plant growth covered geotextiles almost completely during the period of testing, which demonstrated their good compatibility with the greening process. Over the total period of 61 weeks, the residual parts of the biodegradable cellulose web merged with the soil beneath and growing plants. This indicates the potential of such hybrid concepts to contribute a positive effect in greening barren and stony land, in addition to the stabilising function of the steel net.

Production and characterization of fish protein hydrolysate: Effective utilization of trawl by-catch

• Extraction of Fish Protein Hydrolysate (FPH), from discarded by-catch fishes. • Enzymes, namely pepsin and proteinase K, were used to prepare FPH1 and FPH2 • Functional properties like solubility, foaming and emulsifying properties, oil and water-binding capacity, are compared. • FPH 1 was found to have improved functional properties. • It offers the potential to be used for various applications in the food industry. This research was conducted to efficiently extract Fish Protein Hydrolysate (FPH) from Secutor insidiator using papain and proteinase K enzymes. The degree of hydrolysis was found to be 0.8 and 0.9 for proteinase and papain respectively. The proximate analysis of the prepared FPH indicated the levels of Moisture (5.95% and 4.86%), Protein (92.14% and 89.24%), Fat (0.6% and 1.02%) and Ash (6.23 and 4.79) for papain and proteinase respectively. High solubility index (75 – 80%) was observed for the pH levels of 2, 6, 7, 8 & 10 and low solubility index of 31.75% and 32.18% was observed at pH 4 for proteinase and papain respectively. The molecular weight of the hydrolysates was estimated using SDS-PAGE method. Both samples (FPH 1 and FPH 2 ) produced bands at a molecular weight of 15 kDa and the second bands lies in between 25 kDa and 75 kDa. The foaming properties were highest at pH 2 (80 – 85%) and lowest at pH 4 (10-20%). The water binding capacity was observed to be at the highest at 0.2% concentration and there was a gradual decrease from 0.4 to 1.0% concentration of FPH. The oil binding capacity was found to be high at concentrations 0.2 and 1.0% and emulsifying properties were observed to be at the maximum in pH 2 and 10. Among the two Fish Protein Hydrolysates (FPHs) prepared, FPH 1 (proteinase) has comparatively better improved functional properties than FPH 2 (papain).

Development of flaxseed gum/konjac glucomannan with agar as gelling agents with enhanced elastic properties.

The online version contains supplementary material available at 10.1007/s10068-022-01179-9.

Tecnofuncionalidad de harinas integrales de maíces andinos (Zea Mays) nativas y extrudidas

Andean grains have great potential for transformation into new products, but their comprehensive utilization is a technological challenge. The objective of this work was to modify the techno-functional properties of whole-grain flours of the Capia, Bolita and Chulpi Andean maize races by extrusion to obtain flours that potentially improve the quality of gluten-free bread. The flours were extruded in a single screw extruder, using an incomplete orthogonal design with three levels of temperature, moisture and screw speed. The proximal composition of the native whole-grain flours was determined. In native and extruded flours were determined the water absorption index (IAA), water solubility index (ISA), oil absorption capacity (CRO), water binding capacity (CRA) and swelling volume (PH). The extruded Andean maize whole-grain flours presented significant differences in their composition. Most of the variability of data was due to moisture and extrusion temperature. In general, the samples of Capia and Bolita maize had a similar behavior, presenting higher IAA, CRA and pH at high moistures and temperatures; the ISA was higher at low moistures. The CRO did not show significant differences between treatments. Extruded whole-grain flour of Capia and Bolita maize with high IAA, CRA and PH, such as those obtained in the extrusion condition of 120 °C, 25 % H y 80 rpm, could improve the consistency of doughs and the softness of gluten-free breads.

Post-extrusion physical properties, techno-functionality and microbiota-modulating potential of hempseed (Cannabis sativa L.) hull fiber

One-third of hempseed is composed of fiber, yet this major nutrient is far understudied than the seed's oil, protein, polyphenol or cannabinoid fractions. Here we provided a comprehensive and novel study covering the monosaccharide-linkage composition, physical, functional and microbiota-shifting properties of the fiber-rich (>77%) hempseed hull, which is a major industrial processing by-product. Xylose and cellulose-derived 4-linked glucopyranosyl linkage residue dominated the monosaccharide profile and 1D/2D NMR molecular assignments of hempseed hull. Processing with extrusion technology altered the particle size distribution, FTIR structural characteristics, X-ray diffraction crystallinity and thermal stability of hempseed fiber. Extruded hempseed fiber showed significantly greater soluble fiber content, water and oil binding capacity, dynamic modulus and flow viscosity values in oil and oil-water dispersions, delayed starch gelatinization and inhibited its retrogradation. Integration of 16S rRNA gene sequencing and the rapidly emerging metaproteomics revealed a higher population of Megasphaera elsdenii and Lactobacillus spp., along with their expressed ferredoxin and enolases respectively, in porcine faecal samples after fermentation with hempseed hull fiber. Higher production of propionic, butyric and valeric acid from the microbiota was further observed in fiber-treated faecal inoculum. Finally, the possible microbiota modulating-effect of fiber-bounded unique phenylpropionamides ( N - trans -caffeoyltyramine and lignanamides) from hempseed hull was assessed for the first time. • The effects of extrusion on the fiber profile of hempseed hull were investigated. • Linkage and NMR analysis revealed the molecular composition of hempseed fiber. • Functionality of hempseed fiber was tested in oil, water and starch matrices. • Hempseed fiber may alter gut microbial populations and their expressed proteins. • Microbiota and phenolic amides interaction were explored.

Investigation of the effect of structure-regulating additives on the properties of minced fish systems

The search for new effective structure-forming agents of natural origin in order to improve the technology of fish molded products is an urgent scientific and industrial problem. In the course of the study, to obtain minced fish systems, frozen pollock and pink salmon have been used that meet the technical requirements of the current regulatory documentation. Mixtures of cryoconcentrates from seafood, rice and wheat flour, and the enzyme transglutaminase are used as structure-regulating additives. Cryoconcentrates have been made from cucumaria, squid, Pacific herring milt, octopus skin, seaweed, and scallop mantle. The introduction of dry powdered cryoconcentrates of seafood, containing a significant amount of protein substances, has contributed to the binding of water and an increase in the water-retaining capacity of minced pink salmon and pollock. Based on the results of studying the physical, chemical, rheological and organoleptic properties of dispersed minced fish systems, rational amounts of structure-regulating additives have been established: seafood cryoconcentrates - 4.0-5.0 %; transglutaminase - 0.5 %; rice flour - 2.0 %; wheat flour - 1.0-2.0 %. Molded fish products (cutlets, sausages) containing structure-regulating additives had high organoleptic properties after heat treatment. The results of the research should be used in the development of formulations of fish dispersed compositions in the technologies of molded, emulsion and structured products. The established high water-binding capacity of seafood cryoconcentrates justifies the need to study them as natural cryoprotectors in refrigeration technologies.

Effect of chemical treatment duration on physicochemical, rheological, and functional properties of colloidal chitin

In this study, the physicochemical, rheological, and functional properties of colloidal chitin prepared from commercial shrimp shell α-chitin by acid hydrolysis at ambient temperature for various treatment durations were investigated. With increasing treatment duration, the functional properties viz solubility, water and fat binding capacity, and emulsion capacity increased significantly (p<0.05). Color of colloidal chitin had higher lightness values and whiteness index than commercial chitin (p<0.05), but were non-significant (p>0.05) among treatment durations. The degree of deacetylation decreased as treatment duration increased (p<0.05). The Carr index and Housner ratio showed that colloidal chitin powders had poor flowability. The colloidal chitin suspensions had rheothinning tendency, i.e., viscosities of the suspensions decreased with an increase in shear rate. These results suggest that colloidal chitin obtained in this study has better functional properties with enhanced whiteness index than commercial chitin, making it suitable for application as a functional ingredient in the food industry.

Impact of Cassava Starch Varieties on the Physiochemical Change during Enzymatic Hydrolysis.

The enzymatic modification of starch extends its industrial use to flavor delivery and probiotic encapsulants, among other uses. However, it is not known how starch from different cassava varieties responds to enzymatic hydrolysis. Starches from two Ecuadorian cassava varieties (INIAP 650, an edible starch, and INIAP 651, an industrial starch) were partially modified at three enzymatic hydrolysis degrees (0%, 30%, and 50%), and their physicochemical properties were assessed. The structural analysis revealed that both varieties showed progressive structural damage as hydrolysis increases, probably due to exo-hydrolysis. However, deeper pores were observed in INIAP 651 with the SEM analysis. The crystallinity percentage obtained by XRD analyses remained constant in INIAP 651 and decreased (by 26%) in INIAP 650 (p < 0.05). In addition, the amylose–lipid complex index in INIAP 650 remained constant, while INIAP 651 increased (p < 0.05) at 30% hydrolysis (by 93%). In both varieties, hydrolysis increased (p < 0.05) the water holding capacity (WHC) (by 10–14%) and the water binding capacity (WBC) (by 16%), but 50% hydrolysis of INIAP 650 was needed to significantly affect these properties. No differences were observed in the varieties’ thermal properties. Regarding the rheological properties, the variety did not influence the changes in the storage module (G′) and the loss modulus (G″) with the hydrolysis (p > 0.05). However, the phase angle decreased significantly (p < 0.05) with the hydrolysis, being higher in the INIAP 650 variety than in the INIAP 651 variety. In general, the results indicate that the variety affects the response of the starch granule to enzymatic hydrolysis (noticeable in the principal component analysis, PCA) and opens up the possibility to modulate starch properties.

Processing of alfalfa seeds by convective hot air drying, vacuum drying and germination: Proximate composition, techno-functional, thermal and structural properties evaluation

The effect of convective hot air and vacuum drying alone and combined with germination on alfalfa seeds’ proximate composition, techno-functional, thermal and structural properties was investigated. Corresponding properties of treated alfalfa samples were compared with those of commercially available alfalfa sprouts. Both drying and combined germination and drying treatments resulted in increased carbohydrates (41.99–48.82 %), TDF (10.51–12.51 %) and Mg contents (789.49–2119.24 mg/kg), while the reduction in ash, lipid and Fe content compared to raw alfalfa seeds was observed. Alfalfa seeds subjected to combined germination and drying treatment exhibited higher water and oil binding capacities, as well as emulsions with smaller volume mean droplet diameters compared to the raw and dried samples. Conducted treatments resulted in greater thermal stability of globulins and a slight decrease in crystallinity index, although alfalfa seeds’ structure did not change significantly according to FTIR analysis. Differences in applied drying techniques on alfalfa seeds’ properties were not observed.

Effects of Ultrasound and Steam Explosion Treatments on the Physicochemical Properties of Rice Bran Fibre

Rice bran (RB) is an underutilised fibre source due to undesirable effects when incorporated into food products. Thus, this study aims to improve the physicochemical properties of RB by using ultrasound (US) and steam explosion (SE) treatments, making it more usable in food applications. The US treatment of unpurified RB resulted in inconsistent average particle size, water binding capacity (WBC), and swelling capacity (SC). The bulk density (BD) decreased while the oil binding capacity (OBC) increased as the amplitude and time increased. While the purified rice bran resulted in decreased average particle size and BD; and increased WBC, SC, and OBC. The surface microstructure of the unpurified and purified rice bran became more porous, and the colour of the RB was darkened proportionally to the intensity of US treatment. The average particle size of unpurified increased while the purified RB increased after steam explosion treatment regardless of the intensity. The SE treatment also decreased WBC and SC of unpurified and purified RB, but no changes were observed on the surface microstructure of both samples. The BD of unpurified RB decreased, while the BD of purified RB increased after SE treatment. The SE treatment also resulted in a decrease in the OBC of purified RB, but no significant (p &gt; 0.05) improvement was observed in the OBC of unpurified RB. Ultrasound brought these changes in the two treatments more effectively than steam explosion. The alteration of physicochemical properties of RB by the US and SE treatment in this study will allow it to be more applicable in the formulation of food products.

Effects of genotype by environment interaction on agronomic and functional flour properties among cassava genotypes targeted for industrial use

The study was carried out to evaluate the genotype by environment (G × E) interaction on physicochemical and functional properties of ten (10) cassava advanced genotypes and improved varieties. The genotypes and varieties were collected from a multi-location trial (Uniform yield) of the IITA breeding program at four research stations in Malawi. Based on the results, G × E interaction was highly significant (P ≤ 0.001) in explaining the variance of the physicochemical parameters and functional properties. Thus, G × E interaction highly influenced starch and amylopectin contents, swelling power, and water binding capacity. Additive main effect and multiplicative interaction (AMMI) analysis identified I010040, MM06/0045 and TMSL110080 genotypes and Mbundumali, Mpale and Sagonja varieties as the most stable with high yield performance hence recommended for cultivation in a wide range of environments for the production of high quality cassava flour (HQCF) and starch for various industrial applications such as the production of ethanol, biofuels, starch and glucose syrup in chemical industries; thickeners, stabilizers, and texture modifiers in food, bakery and confectionery industries.

Targeted pectin depletion enhances the potential of high-pressure homogenization to increase the network forming potential of tomato cell wall material

The current study addresses the influence of pectin depletion on the potential of high-pressure homogenization (HPH) to increase the network forming potential of the cell wall material (CWM) from tomato. Therefore, the microstructure, water binding capacity and viscoelastic properties of the alcohol-insoluble residue (AIR) and unextractable fractions (UFs) obtained after different levels and methods of pectin extraction were determined in suspension before and after functionalization by HPH. Before HPH, the AIR and the UFs obtained by solvent-based pectin extraction were all characterized by particles displaying cell-like morphology and the storage modulus (G′) of the respective suspensions was maximal at partial pectin depletion. The network forming potential of the CWM could only be increased by HPH when extensive disruption of the cell wall network was realized instead of mainly breakage. Even when higher pressure levels were applied (up to 80 MPa), preceding weakening of the cell wall network by pectin extraction was a prerequisite to favor efficient disruption of the CWM during HPH above deformation and breakage. Apart from the effect of partial pectin depletion as such on the cell wall strength, the impact of the extraction conditions (e.g., acid conditions at high temperature) weakening the residual cell wall seemed important. This had repercussions on the potential of HPH to functionalize the CWM. While the G’ decreased upon HPH (evaluated at 20 MPa) for non-pectin-depleted or partially pectin-depleted CWM generated by using mild extraction conditions, a clear increase was observed upon HPH of CWM which was partially or extensively pectin-depleted using harsher extraction conditions.

Effects of Protein Functionality on Myofibril Protein-Saccharide Graft Reaction.

The myofibril protein (MP) isolate-saccharide graft reactions was prepared using the Maillard reaction with saccharides. The effects of various saccharides on protein functionality and quality of the Maillard reaction were investigated and compared with those of MP. The grafting degree of the MP isolate-saccharide graft reaction was significantly higher in the reducing sugar-treated groups (lactose, glucose, fructose, and palatinose). The browning intensity of the MP isolate-saccharide graft reaction with fructose, sucrose, and erythitol was higher than that observed in the control reaction (p<0.05). MP that reacted with reducing sugars (glucose, fructose, palatinose, and lactose) had fainter bands than MP that reacted with non-reducing sugars (sucrose, erythitol, trehalose, sorbitol, and xylitol). MPs conjugated with glucose exhibited higher protein solubility. The palatinose and lactose treatments were maximum in water binding capacity, though no significant difference in oil binding capacity among the saccharide treatments was observed. The emulsion stability of the MP isolate-saccharide graft reaction with palatinose and erythitol was higher than that of the control reaction. Therefore, reducing sugars have good protein functionality in the MP isolate-saccharides graft reaction.

Utilization of whey in bakery products-A review

Whey is a vast repository of valuable nutrients and serves as a key ingredient in the bakery sector. Whey being a significant by product of the dairy industry is necessary to be utilized to reduce the burden of its disposal on the environment, which is attributed to the high BOD of whey. Whey based ingredients find an ocean of application in foods. Whey based ingredients have superior functional properties attributable to whey proteins which results in enhancement of textural and chemical properties of products they are applied in. Whey proteins are used as fat replacers, emulsifiers, flavour and appearance enhancers etc in a wide category of bakery products. Whey based ingredients can negate the use of dough conditioners due to high water binding capacity which aids in developing improved texture and fine even crumb. Whey ingredients can boost levels of protein, calcium, potassium and other minerals in bakery products. With increasing demand for clean label products and low fat products with the same textural attributes as full fat ones the demand for whey ingredients is surging. In this article we review the applications of whey based ingredients in bakery products.

Comparison of spontaneous and ragi fermentations on the physicochemical and functional properties of cereal flours

Spontaneous and ragi fermentations are the most common methods in producing traditional fermented foods in Indonesia. The present work aimed to compare the impacts of spontaneous and ragi fermentations on cereal flour properties. Three kinds of cereal, namely whole sorghum, waxy coix, and white maize were processed into flours through spontaneous fermentation, ragi fermentation, and without fermentation (control). Fermentation methods were adopted from the Indonesian traditional processing methods. Cereal grains were immersed for 72 h in distilled water (1:2 w/v) for spontaneous fermentation, and in 1% ragi tapai solution (1:2 w/v) for ragi fermentation. Meanwhile, native flour (without fermentation) was produced by grounding and sieving the cereal grains. Results showed that both fermentation techniques significantly altered the physical properties of cereal flours, as indicated by the increase in lightness index and decrease in water-binding capacity and viscosity. However, cereal flours’ chemical and functional properties remain unchanged during fermentation, except for lipid and amylose. Spontaneous fermentation significantly resulted in the lowest lipid content of cereal flours, while ragi fermentation resulted in the lowest amylose content of cereal flours. Sorghum flour generally showed better nutritional properties among the examined cereal flours, especially lipid, protein, and dietary fibre. Meanwhile, waxy coix and white maize flours had the highest folate.

Physicochemical and microstructural mechanisms for quality changes in lightly salted tilapia (Oreochromis niloticus) fillets during frozen storage.

Frozen tilapia fillet has become a leading aquatic product. High drip loss, dry and fibrous mouthfeel, and an unappealing appearance are its main problems. It was hypothesized that light salting could improve the quality, and that the preparation conditions would affect the storage stability of frozen tilapia fillets. The quality changes of lightly salted tilapia fillets were evaluated during frozen storage, and the underlying mechanisms were studied from the physicochemicaland microstructural perspectives. Though the salt content was 1.5% in all samples,the amount of ice crystals in frozen tissues decreased with the descending water content and freezing point (P < 0.05). No intracellular voids were observed in the samples prepared under proper salting conditions, and the myofibers were plump and smooth after freezing-thawing, which contributed to the high water-holding capacity of lightly salted fillets. After 28 days,the water-binding capacity of the salted groups was 14.69%-18.62% higher than that of their unsalted counterparts (P < 0.05). The reduced protein solubility in the salted fillets was likely to have occurred because the solubilized and unfolded proteins interacted more easily during frozen storage. The oxidation degree of myofibrillar proteins was also affected by salting condition, and the fillets with less oxidized sulfhydryl groups maintained high springiness after 28 days of frozen storage. The salting condition of 9% NaCl solution for 1h was recommended for the preparation of lightly salted fillets from freshwater fish, taking into account quality, processing efficiency, and storage stability. The enhanced water-holding capacity and texture of lightly salted tilapia fillets were attributed to modified physicochemical and microstructural properties. These results could provide a scientific basis for the processing and storage of high-quality, frozen, lightly salted fillets from freshwater fish. © 2022 Society of Chemical Industry.

Mechanically Enhanced Salmo salar Gelatin by Enzymatic Cross-linking: Premise of a Bioinspired Material for Food Packaging, Cosmetics, and Biomedical Applications.

Marine animal by-products of the food industry are a great source of valuable biomolecules. Skins and bones are rich in collagen, a protein with various applications in food, cosmetic, healthcare, and medical industries in its native form or partially hydrolyzed (gelatin). Salmon gelatin is a candidate of interest due to its high biomass production available through salmon consumption, its biodegradability, and its high biocompatibility. However, its low mechanical and thermal properties can be an obstacle for various applications requiring cohesive material. Thus, gelatin modification by cross-linking is necessary. Enzymatic cross-linking by microbial transglutaminase (MTG) is preferred to chemical cross-linking to avoid the formation of potentially cytotoxic residues. In this work, the potential of salmon skin gelatin was investigated, in a comparative study with porcine gelatin, and an enzymatic versus chemical cross-linking analysis. For this purpose, the two cross-linking methods were applied to produce three-dimensional, porous, and mechanically reinforced hydrogels and sponges with different MTG ratios (2%, 5%, and 10% w/w gelatin). Their biochemical, rheological, and structural properties were characterized, as well as the stability of the material, including the degree of syneresis and the water-binding capacity. The results showed that gelatin enzymatically cross-linked produced material with high cross-linking densities over 70% of free amines. The MTG addition seemed to play a crucial role, as shown by the increase in mechanical and thermal resistances with the production of a cohesive material stable above 40°C for at least 7days and comparable to porcine and chemically cross-linked gelatins. Two prototypes were obtained with similar thermal resistances but different microstructures and viscoelastic properties, due to different formation dynamics of the covalent network. Considering these results, the enzymatically cross-linked salmon gelatin is a relevant candidate as a biopolymer for the production of matrix for a wide range of biotechnological applications such as food packaging, cosmetic patch, wound healing dressing, or tissue substitute.