Effect of freezing on protein denaturation and gelling capacity of jumbo squid (Dosidicus gigas) mantle muscle

The mechanism of egg white protein to enhance the thermal gel properties of giant squid (Dosidicus gigas) surimi

In this paper, the interaction between egg white protein (EWP) and giant squid surimi was regulated by changing the ratio of surimi to EWP, and the mechanism of EWP on the gel properties of giant squid surimi was analyzed. The results showed that when the proportion of EWP was 16: 1, the hardness and springiness of surimi gel were the highest, reaching 645.5 g and 1.258, respectively. The gel strength reached 0.634 kg, the cooking yield of surimi gel increased by 27 % and the water loss decreased to less than 10 %. A significant increase in the proportion of fixed water and a decrease in the proportion of free water indicated that mixed surimi improved the "trapping" ability of water molecules, induced the formation of a more ordered "cage"-like structure, and significantly increased the water holding capacity and whiteness of surimi gels.

Impact of high pressure impregnation and air drying on the quality of Dosidicus gigas slices

Humboldt squid (Dosidicus gigas) is the most abundant cephalopod in the fishing industry, and its high nutritional and organoleptic properties make it a go-to food product for consumers. Therefore, developing new processing techniques seems imperative to minimize quality deterioration and provide products with appropriate characteristics. The study aimed to determine the effect of high-pressure impregnation (HPI) pretreatment on hot air-drying kinetics and the quality of Humboldt squid slices. Various pressures, times, and concentrations of osmotic solution during HPI were evaluated, followed by drying at 40 and 60 °C. The HPI pretreatment reduced the drying time by around 26% when dried at 40 °C, and only 18% when dried at⋅ 60 °C compared with unpretreated samples. The Weibull, Page, and Logarithmic models were considered for experimental drying curve modeling. Diffusion coefficient values varied from 3.82 to 6.59 × 10-9 m2/s for all drying conditions. Moreover, the color, texture, and water-holding capacity were determined. Rehydration capacity values increased due to less damage to cellular tissue than the control (HPI-untreated dried samples). Also, scanning electron microscope (SEM) images showed a compacted structure of HPI-dried squid samples. Overall, HPI proved to be a beneficial pretreatment as it reduced drying time and improved the quality characteristics of Humboldt squid.

Using maltodextrin and state diagrams to improve thermal transitions in tilapia fillet (Oreochromis spp.)

BACKGROUND

Tilapia (Oreochromis spp.) in the form of frozen fillets is one of the fishes with the highest commercial production levels worldwide. However, protein denaturation, membrane rupture, and lipid oxidation are commonly observed in fillets when stored at standard commercial freezing temperatures for long periods. This study proposes, for the first time, the use of maltodextrin and state diagrams to define processing strategies and suitable storage temperatures for fresh and dehydrated tilapia fillets. Differential scanning calorimetry (DSC) was used to study the effect of maltodextrin weight fractions (W MD ) of 0, 0.4, and 0.8 on the thermal transitions of tilapia fillets as a function of solid mass fractions (W s ).

RESULTS

The glass transition temperature curve (T g vs . W s ) and characteristic parameters of maximal freeze concentration (T g ' ,T m ' ,W s ' ) of tilapia increased significantly with the addition of maltodextrin. Using developed state diagrams, freezing and storage temperatures of -22 °C, -15 °C, and -10 °C (P < 0.05) for long-term preservation were defined for tilapia fillets produced withW MD of 0, 0.4, and 0.8.

CONCLUSION

Maltodextrin is an excellent alternative as a cryoprotectant and drying aid to increase the thermal parameters of tilapia fillets by achieving frozen storage temperatures above the standard commercial freezing temperature of -18 °C. © 2023 Society of Chemical Industry.

Cephalopods as Challenging and Promising Blue Foods: Structure, Taste, and Culinary Highlights and Applications

Foods are complex systems due to their biological origin. Biological materials are soft matter hierarchically structured on all scales from molecules to tissues. The structure reflects the biological constraints of the organism and the function of the tissue. The structural properties influence the texture and hence the mouthfeel of foods prepared from the tissue, and the presence of flavour compounds is similarly determined by biological function. Cephalopods, such as squid, cuttlefish, and octopuses, are notoriously known for having challenging texture due to their muscles being muscular hydrostats with highly cross-linked collagen. Similar with other marine animals such as fish and crustaceans, cephalopods are rich in certain compounds such as free amino acids and free 5′-ribonucleotides that together elicit umami taste. Scientific investigations of culinary applications of cephalopods as foods must therefore involve mechanical studies (texture analysis), physicochemical measurements of thermodynamic properties (protein denaturation), as well as chemical analysis (taste and aroma compounds). The combination of such basic science investigations of food as a soft material along with an exploration of the gastronomic potential has been termed gastrophysics. In this review paper, we reviewed available gastrophysical studies of cephalopod structure, texture, and taste both as raw, soft material and in certain preparations.

Recent development in evaluation methods, influencing factors and control measures for freeze denaturation of food protein

Frozen storage is most widely adopted preservation method to maintain food freshness and nutritional attributes. However, at low temperature, food is prone to chemical changes such as protein denaturation and lipid oxidation. In this review, we discussed the reasons and influencing factors that cause protein denaturation during freezing, such as freezing rate, freezing temperature, freezing method, etc. From the previous literatures, it was found that frozen storage is commonly used to prevent freeze induced protein denaturation by adding cryoprotectants to food. Some widely used cryoprotectants (for example, sucrose and sorbitol) have been reported with higher sweetness and weaker cryoprotective abilities. Therefore, this article comprehensively discusses the new cryopreservation methods and providing comparative study to the conventional frozen storage. Meanwhile, this article sheds light on the freeze induced alterations, such as change in functional and gelling properties. In addition, this article could be helpful for the prolonged frozen storage of food with minimum quality related changes. Meanwhile, it could also improve the commercial values and consumer satisfaction of frozen food as well.

The differences of muscle proteins between neon flying squid (Ommastrephes bartramii) and jumbo squid (Dosidicus gigas) mantles via physicochemical and proteomic analyses

Neon flying squid (OB) and jumbo squid (DG) mantles were evaluated to reveal the similarities and differences in their physicochemical features and protein abundances. Microstructural results indicated that the OB mantle exhibited numerous myofibril fragments and disordered microstructures after frozen storage compared with DG tissues. Chemical analysis suggested that freezing resulted in a rapid decrease in myofibrillar protein (MP) content, Ca²⁺-ATPase activity, and total sulfhydryl content, and promoted the increase in carbonyl content of MPs in both OB and DG. While, DG presented better MP stability than OB muscle after 120 days of frozen storage. Label-free proteomic analysis detected 24 down- and 33 up-regulated differentially abundant proteins (DAPs) in OB and DG mantles. Identified DAPs including isocitrate dehydrogenase and malic enzyme initiated a rapid decrease in the MP properties in OB samples. Moreover, DAPs were related to cytoskeleton function, including paramyosin, tropomyosin, and troponin C, which improved the stability of DG in response to freezing-induced changes.

Influence of pH, ionic strength and isoascorbic acid on the gel-forming ability of Jumbo squid muscle (Dosidicus gigas)

The effect of pH and ionic strength (μ) on the extraction capacity of myofibrillar proteins from Jumbo squid mantle muscle along with the addition of isoascorbic acid (IA) in its gel-forming ability (GFA) were evaluated. The results indicate that μ had a greater impact (p < 0.05) than pH on the extraction of muscle myofibrillar proteins. The effectiveness of IA, as the precursor of dehydro-isoascorbic acid (DIA), on the oxidation of sulfhydryl groups (-SH) to disulfide bonds (-SS-) of extracted proteins at 0.6 μ was also evaluated. During the sol-gel transition the -SH groups initially present in the protein system decreased (p < 0.05) due to the combined effect of heat treatment (90 °C/30 min) and the addition of IA; however, the oxidative effect of IA reduced (p < 0.05) the GFA of Jumbo squid muscle proteins. Results also indicated that NaCl at 2.8% rather than at 2.5% during gel preparation significantly (p < 0.05) improves its GFA.

Effects of Glazing with Preservatives on the Quality Changes of Squid during Frozen Storage

This study aimed to investigate the effects of glazing with sodium polyacrylate (SP) and D-sodium erythorbate (DSE) on the quality changes of squid during frozen storage. Frozen squid samples were randomly divided into seven groups: (1) CK (unglazed); (2) WG (distilled water-glazed); (3) SG (0.1% SP -glazed); (4) SG-1DSE (0.1% SP with 0.1% DSE -glazed); (5) SG-3DSE (0.1% SP with 0.3% DSE-glazed); (6) SG-5DSE (0.1% SP with 0.5% DSE-glazed); (7) WG-1DSE (0.1% DSE-glazed). The efficacy of the different coatings was evaluated using various indicators, such as water holding capacity (WHC), pH value, low field nuclear magnetic resonance (LF-NMR), color, malondialdehyde (MDA) content value, free amino acids (FAAs) content, intrinsic fluorescence intensity (IFI) and the total sulfhydryl content (SH) content. Intrinsic fluorescence intensity (IFI) and low field nuclear magnetic resonance (LF-NMR) were used as fast monitoring techniques to monitor changes in quality of squid samples. The results showed that compared with the CK and WG groups, coating with either SG or DSE alone resulted in reduced rate of moisture loss (p < 0.05), lipid oxidation (p < 0.05) protein degradation (p < 0.05) and prolonged its shelf-life. The combination of glazing treatment with SG and DSE (groups SG-1DSE, SG-3DSE and SG-5DSE) further improved the protective effects of coating, particularly in the SG-3DSE group. Therefore, the glazing of SG-3DSE is recommended to be used to control the quality of frozen squid and to prolong its shelf-life during frozen storage.

Physicochemical characterization of actomyosin-paramyosin from giant squid mantle (Dosidicus gigas)

BACKGROUND

The giant squid (Dosidicus gigas) has been proposed as raw material to obtain myofibrillar protein concentrates. However, it has been observed that colloidal systems formed from squid proteins have limited stability. Therefore, the isolation and characterization of the actomyosin-paramyosin isolated (API) complex were performed, because they are the main proteins to which functionality has been attributed.

RESULTS

Densitogram analysis revealed 45% of actin, 38% of myosin and 17% of paramyosin. The amino acid profile indicates a higher proportion of acidic amino acids, which gives a higher negative charge; this was supported by the zeta potential. Total sulfhydryl (TSH) content was lower compared with proteins of other aquatic species.

CONCLUSION

The higher percentage of actin in relation to myosin, the presence of paramyosin, as well as the low content of sulfhydryl groups, could comprise the main causes of the low technological functional property of proteins from D. gigas mantle. © 2017 Society of Chemical Industry.

Application of differential scanning calorimetry to estimate quality and nutritional properties of food products

Over the past years, both food researchers and food industry have shown an increased interest in finding techniques that can estimate modifications in quality, nutritional, and thermophysical properties of food products during processing and/or storage. For instance, differential scanning calorimetry (DSC) has attracted the interest of scientific community because only a small amount of sample is needed for analysis. Moreover, it does not require any specific sample preparation, and is a repeatable and reliable method. In addition, DSC methodology needs a short time for experiments compared with other techniques used for the same purpose. At this stage of investigation, there is a need to evaluate the commonly accepted and new emerging DSC applications to establish the optimum conditions of emerging processing. This paper reviews the current and new insights of DSC technique for the estimation of quality, nutritional, and thermophysical properties of food products during conventional and emerging processing and/or subsequent storage. The estimation of different properties in several food matrices after processing and/or storage is also discussed.

Effect of pulsed ultrasound on the physicochemical characteristics and emulsifying properties of squid (Dosidicus gigas) mantle proteins

Food technologists are always looking to improve the functional properties of proteins. In this sense, in last years ultrasound has been used to improve some functional properties. For this reason, and considering that jumbo squid is an important fishery in northwest Mexico, the purpose of this research was to determine the effect of pulsed ultrasound on the physicochemical characteristics and emulsifying properties of squid (Dosidicus gigas) mantle proteins. Pulsed ultrasound (20kHz, 20, and 40% amplitude) was applied for 30, 60, and 90s to a protein extract prepared from giant squid mantle causing an increase (p<0.05) in surface hydrophobicity (S_o) from 108.4±1.4 to 239.1±2.4 after application of pulsed ultrasound at 40% of amplitude for 90s. The electrophoretic profile and the total and reactive sulfhydryl contents were not affected (p⩾0.05) by the ultrasound treatment. The emulsifying ability of the protein solution was improved (p<0.05), whereas the Emulsifier Activity Index (EAI) varied from123.67±5.52m²/g for the control and increased up to 217.7±3.8m²/g after application of the ultrasound. The Stability Emulsifier Index (EEI) was improved at 40% of amplitude by 60 and 90s. The results suggested that pulsed ultrasound used as pretreatment induced conformational changes in giant squid proteins, which improved the interfacial association between protein-oil phases, thus contributing to the improvement of their emulsifient properties.