Jumbo Squid Muscle Research Articles

Supplementation of corn tortilla with freeze-dried jumbo squid muscle flour: physicochemical properties and microbiological stability during storage

Corn tortilla is one of the most consumed foodstuffs in Latin America, representing a good nutrients source, although deficient in some essential amino acids. Jumbo squid (Dosdicus gigas) muscle possesses high-quality protein, useful for tortilla supplementation. Our objective was to elaborate corn tortillas supplemented with jumbo squid muscle flour (JSMF), using composite corn flours containing JSMF (2.5 and 5.0%), to improve their nutritional quality without affecting their physicochemical/sensory properties and storage stability. Supplementation with 5% JSMF increased (P<0.05) tortilla protein level, and the essential amino acids versus the control. The 2.5% JSMF tortillas were tasteful and acceptable (P≥0.05) as the control. JSMF addition showed an antimicrobial effect on mesophilic and psychrophilic bacteria; however, yeast and moulds grew beyond the permissible limit at day 5 of storage. JSMF addition did not affect (P≥0.05) the cutting force, with all tortillas tending to become harder to roll without cracking as storage elapsed. Tortilla storage stability (supplemented or not) was 3 days at 2–4 °C. Results suggest the feasibility of adding JSMF to corn tortilla, improving its nutritional characteristics without markedly affecting other parameters.

Utilisation of collagenolytic enzymes from sierra fish (Scomberomorus sierra) and jumbo squid (Dosidicus gigas) viscera to generate bioactive collagen hydrolysates from jumbo squid muscle.

Crude extracts of collagenases from jumbo squid (Dosidicus gigas) hepatopancreas and sierra fish (Scomberomorus sierra) viscera were used to hydrolyse squid muscle collagen into peptides with inhibitory capacity over angiotensin I-converting enzyme (ACE) and ABTS free radicals [2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid)], as a measure of their antihypertensive potential and antioxidant activity, respectively. Proteins from 20 to 200kDa were found in both enzyme extracts; however, in comparison to the jumbo squid extract (JSE), the extraction yield and specific activity of the enzymatic sierra fish extract (SFE) were ≈ 40% greater, suggesting the presence of enzymes with different collagenolytic activity. Moreover, the utilised collagen was obtained with a yield of 0.98 ± 0.09g/100g muscle from jumbo squid arms, which after an incubation with JSE and SFE generated peptides with different biological activity. However, the collagen hydrolysates from the enzymatic SFE contained a higher proportion of low-molecular-weight peptides than that obtained from JSE (15.2 and 7.9% of < 3kDa peptides, respectively). Finally, the antioxidant potential and ACE-inhibitory activity were increased after hydrolysis, being the SFE the one that showed a greater increase of both biological activities (82.28% of ACE inhibition and 64% of ABTS inhibition).

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.

Partial Characterization of a Low-Molecular-Mass Fraction with Cryoprotectant Activity from Jumbo Squid (Dosidicus gigas) Mantle Muscle.

SUMMARYFreezing conditions affect fish muscle protein functionality due to its denaturation/aggregation. However, jumbo squid (Dosidicus gigas) muscle protein functionality remains stable even after freezing, probably due to the presence of low-molecular-mass compounds (LMMC) as cryoprotectants. Thus, water-soluble LMMC (<1 kDa) fraction obtained from jumbo squid muscle was evaluated by Fourier transform infrared spectrometry. From its spectra, total carbohydrates, free monosaccharides, free amino acids and ammonium chloride were determined. Cryoprotectant capacity and protein cryostability conferred by LMMC were investigated by differential scanning calorimetry. Fraction partial characterization showed that the main components are free amino acids (18.84 mg/g), carbohydrates (67.1 µg/mg) such as monosaccharides (51.1 µg/mg of glucose, fucose and arabinose in total) and ammonium chloride (220.4 µg/mg). Arginine, sarcosine and taurine were the main amino acids in the fraction. LMMC, at the mass fraction present in jumbo squid muscle, lowered the water freezing point to –1.2 °C, inhibiting recrystallization at 0.66 °C. Significant myofibrillar protein stabilization by LMMC was observed after a freeze-thaw cycle compared to control (muscle after extraction of LMMC), proving the effectiveness on jumbo squid protein muscle cryo- stability. Osmolytes in LMMC fraction inhibited protein denaturation/aggregation and ice recrystallization, maintaining the muscle structure stable under freezing conditions. LMMC conferred protein cryostability even at the very low mass fraction in the muscle.

Physicochemical Changes of Connective Tissue Proteins in Jumbo Squid (Dosidicus gigas) Muscle During Ice Storage

Connective tissue (CT) proteins in jumbo squid (Dosidicus gigas) play an important role because they are the responsible for the union between various cells; hence, there is a close relationship between their functions and muscle firmness during ice storage. In this study, the thermal resistance and solubility of the CT extracted from the fins, mantle and arms of jumbo squid during ice storage (20 days) was evaluated. The CT was fractionated based on solubility [NaCl-soluble (SSCT) and insoluble (ICT)]. The solubility of the CT was affected during ice storage. An increase in the thermal resistance of the SSCT after 10 days with a subsequent decrease was found in the mantle. Furthermore, the ICT was thermally more resistant than the SSCT in all the anatomical regions. Finally, the electrophoretic profile revealed that structural changes occurred, causing changes in its solubility, due to an increase in the thermal resistance. Practical Applications Jumbo squid (Dosidicus gigas) is an important seafood resource in Mexico, which is commercialized primarily iced and fresh-frozen. Its muscle connective tissue (CT) has different physicochemical characteristics that differ from other seafood products; it is thermally more resistant and might be responsible for the textural changes during ice storage. Moreover, specific studies about the behavior of CT proteins in such organism may result in improved post-catch management of jumbo squid muscle, focused on the processing of the species in the food industry or anywhere that CT proteins are used as raw material. The main objective of this research is to investigate solubility changes and thermal resistance of CT proteins of iced jumbo squid mantle.

Relationship between lysyl oxidase activity, pyridinoline content and muscle texture during ice storage of jumbo squid (Dosidicus gigas)

SummaryCollagen fibres, stabilised by lysyl oxidase (LOX), play an important role in jumbo squid because they are responsible for the union between various cells; therefore, a close interdependence between their functions and muscle firmness during ice storage has been suggested. In this study, the relationship between LOX activity, pyridinoline (Pyr) content and muscle texture (SF) during ice storage of jumbo squid mantle was evaluated. LOX activity was confirmed within the range of 4.1–7.1 × 10−3 U g−1 of protein, leading to an increase in Pyr content, detected in the range of 0.85–1.32 mmol mol−1 of collagen after 5–20 days. The SF of the muscle became harder during the ice storage time, increasing from 21.08 to 37.95 N. It was therefore possible to establish the relationship between LOX activity, collagen cross‐links (Pyr content) and texture patterns during ice storage of jumbo squid muscle, which increased after 20 days.

Effects of pH and Sodium Chloride on the Gelling Properties of a Protein Concentrate Obtained from Jumbo Squid Mantle (Dosidicus Gigas)

Jumbo squid (Dosidicus gigas) is an underutilized fishery resource in the Gulf of California. Jumbo squid muscle could potentially be utilized to manufacture protein concentrates to be used as a base for surimi or as a food ingredient. However, the main problem is the low gelling ability of these protein concentrates compared those of with fish species. Consequently, the present study evaluated the effects of pH and the NaCl concentration on the gelling properties of protein concentrates from squid mantle. According to texture profile analysis, improved gelling properties were obtained at pH 6.0 and 1% of NaCl. During the sol-gel transition, decreased surface hydrophobicity that corresponded to an increased intensity of α-helix structures was detected. Moreover, the total sulfhydryl content decreased during gel formation. Viscoelasticity and water holding capacity analyses showed the formation of a more structured gel at pH 7.0. The higher enthalpy and denaturation temperature detected by differential scanning calorimetry at pH 7.0 and 1% NaCl showed that both variables (pH and NaCl concentration) affected the protein structure and conformation. The results demonstrated that varying pHs and NaCl concentrations improved the gelling properties of protein concentrates from squid.

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

The effect of freezing storage on protein denaturation and gelling capacity of jumbo squid muscle was evaluated. Squid mantle muscle samples were evaluated in both, ground (G) and whole presentations (W), and in a control consisting of ground muscle (C). G and W samples were submitted to two freezing storage periods (−20 °C), 1 day (GF-1, WF-1) and 30 d (GF-30, WF-30). Proximate composition, pH, surface hydrophobicity (SoANS) and differential scanning calorimetry (DSC) were evaluated. Additionally folding test, texture profile analysis and water holding capacity were monitored in gels prepared with the different samples. The quality of gels was not affected by any treatment. Neither freezing, grinding or storage period had a significant effect on the above parameters, suggesting that functional properties of the squid mantle muscle are highly stable. DSC did not reveal any denaturation, also adducing high stability of muscle proteins. SoANS revealed that freezing, grinding and time, had an effect on protein properties; however, these influences were apparently not significantly enough to have a further effect on the gel quality. Finally, gelling capacity of muscle was not affected by any factor. Considering these results, squid muscle may be considered as a useful resource either fresh or frozen.

Lysyl oxidase from jumbo squid (Dosidicus gigas) muscle: purification and partial characterization

SummaryLysyl oxidase (LOX; E.C.1.4.3.13) was purified from jumbo squid muscle (Dosidicus gigas) with 1900‐fold and yield 1.9%, and characterized for the first time. The purification procedure consisted of fractionation with urea and a combination of size‐exclusion and anion‐exchange chromatography. The enzyme had a molecular weight of 32 kDa, as estimated by SDS‐PAGE. Using a specific LOX substrate (1,5‐diaminopentane), its optimum activity was determined at pH 8.2 and 65 °C. Activation energy (Ea) of the enzyme was 69.94 kJ K−1 mol−1. The enzyme was strongly inhibited by β‐aminopropionitrile fumarate (BAPN), a specific LOX inhibitor. Moreover, purified LOX was able to work at different temperatures (20–90 °C) at pH 8.2. Although further research is needed, the results from this work suggest that based on LOX activity, this enzyme may be of practical use in preventing textural changes in jumbo squid during storage or processing.

Lysyl oxidase from jumbo squid (Dosidicus gigas) muscle: detection and partial purification

SummaryLysyl oxidase (LOX) was detected and partially purified from jumbo squid (Dosidicus gigas) muscle, for the first time. A procedure for the purification of LOX from jumbo squid muscle which consisted of urea extraction, Sephadex G‐75 and anion exchange chromatography was developed. Activity of partially purified LOX was 390‐fold higher than the original extract. Two protein fractions with 32 and 24 kDa were detected by SDS‐PAGE. The enzyme was strongly inhibited by β‐aminopropionitrile fumarate, a specific LOX inhibitor. LOX was purified with 3.8% yield, showing a specific activity of 0.078 IU mg−1 protein. This knowledge will help understand the behaviour of jumbo squid protein during cool storage or manufacture.

PROTEIN SOLUBILITY AND PRODUCTION OF GELS FROM JUMBO SQUID

Solubility at several ionic strengths (0 to 1.0 M), pH (2 to 13) and gelling capacity of jumbo squid Dosidicus gigas muscle proteins were evaluated. Protein recovery was >90% at pH 9–12. Autohydrolysis was evaluated and affected only sarcoplasmic proteins. Folding score was 5 on all gels. Strength was higher for thermal gels prepared from squid fin (50.2 ± 1.2 N) than that prepared from the mantle (23.4 ± 2.5 N). There was no significant difference in gel strengths from previously frozen (46.4 ± 7.5 N) and never-frozen samples (43 ± 5.5 N). Moisture, water drip and water-holding capacity were evaluated on thermal gels. There were significant differences between frozen and never-frozen samples. Results on solubility and gel forming capacity of the proteins from mantle and fin of jumbo squid suggest that these properties can provide additional value to this resource. PRACTICAL APPLICATIONS Jumbo squid is a rich source of high-quality protein. Obtaining sophisticated products would be an easy way to take advantage of the high-quality proteins in jumbo squid muscle. Knowledge of the functional properties of those proteins is needed to achieve this. The use of such properties, such as gel-forming capacity, which are similar to other proteins used in the food industry, will give jumbo squid added value. The results described here indicate that jumbo squid proteins may be useful as a food ingredient because of their solubility and gel-forming capacity.

Isolation and properties of AMP deaminase from jumbo squid (Dosidicus gigas) mantle muscle from the Gulf of California, Mexico

Adenosine monophosphate (AMP) deaminase was purified from jumbo squid mantle muscle by chromatography in cellulose phosphate, Q-Fast and 5′-AMP sepharose. Specific activity of 2.5U/mg protein, 4.5% recovery and 133.68 purification fold were obtained at the end of the experiment. SDS–PAGE showed a single band with 87kDa molecular mass, native PAGE proved a band of 178kDa, whereas gel filtration detected a 180kDa protein, suggesting the homodimeric nature of this enzyme, in which subunits are not linked by covalent forces. Isoelectric focusing of this enzyme showed a pI of 5.76, which agrees with pI values of AMP deaminase from other invertebrate organisms. AMP deaminase presented a kinetic sigmoidal plot with Vmax of 1.16μM/min/mg, Km of 13mM, Kcat of 3.48μM.s−1 and a Kcat/Km of 267 (mol/L)−1.s−1. The apparent relative low catalytic activity of jumbo squid muscle AMP deaminase in the absence of positive effectors is similar to that reported for homologous enzymes in other invertebrate organisms.