Effect of storage at 0 °C on mantle proteins and functional properties of jumbo squid

Effect of iced storage of jumbo squid mantle with fin on gelling capacity and changes in protein fractions and functional properties of jumbo squid mantle protein during storage at 0 °C were assessed. Most values of texture variables in gels did not significantly change during storage. On average, they were: strength 65.07 ± 4.71 N; elasticity 68.14 ± 5.3%, fracturability 52.97 ± 1.28 N and cohesiveness 36.6 ± 0.1%. Protein solubility increased more than 40%. Whippability increased during storage for 16 days at 0 °C (81–162%), as did foam stability (73–94%). Results suggest that iced squid mantle protein is a suitable ingredient for food products where these functional properties are desirable. Muscle fibres of squid mantle undergo various changes during storage. At 0 °C, they are disrupted, whereas at −20 °C, they aggregate and develop empty spaces in the tissue.     

EFFECT OF pH AND TEMPERATURE ON JUMBO SQUID PROTEINS

Evaluation of the effect of pH (2 to 13) and temperature (0 to 50C) on functional properties of jumbo squid proteins was performed, followed by a 2  ×  3 factorial design for producing squid protein hydrolysates bearing useful functional properties. In particular, the effects of pH (8, 9 and 10) and temperature (30, 35, 40C) were evaluated. Alcalase and papain were tested on each treatment. The protein recovery, whippability and emulsifying capacity of the hydrolysates were evaluated. Almost 80% of the proteins were recovered in water-soluble form after hydrolysis with papain at pH 10 at the three temperatures. The highest values of whippability (245  ±  17.7%), foam stability (100%), emulsion-forming capacity (27  ±  0.97%) and stability (99.99  ±  8.8%) occurred with papain-produced hydrolysates. When squid protein was treated at 50C and pH 8, the highest whippability value (390.0  ±  0.1%) and foam stability (100%) were obtained when no enzyme was added.

PRACTICAL APPLICATIONS

This paper assesses how process variables, particularly temperature and pH, affect the functional properties of squid proteins. Making use of such process variables will produce more useful and efficient processes, as the application of a hydrolysis system. The processing of jumbo squid protein to obtain proteins bearing adequate functional properties would be an inexpensive way to provide added value to this marine resource and the production of a high-quality protein ingredient. These results hold promise for jumbo squid proteins as useful food ingredient because of their functional properties.     

Jumbo squid (Dosidicus gigas) mantle muscle gelled-emulsified type product: formulation, processing and physicochemical characteristics

Jumbo squid ( Dosidicus gigas ), an abundant species in the Gulf of California, can have a great potential for production of gelled-emulsified type products. Thus, formulation, processing and physicochemical characteristics of frankfurter-type product from jumbo squid mantle muscle (JSF) was achieved. JSF were vacuum-packed and stored at 2–4 °C. Samples were analysed for physicochemical (colour, texture, TBARS, peroxide value, folding test, pH, and water content and holding capacity) and microbial changes at regular intervals during storage for up to 27 days. The sensory quality of the product was also evaluated. Shear force, cohesiveness and colour (hue angle and total colour difference) were the most affected ( P  <   0.05) parameters at day 27, changes most probably because of microbial growth as total aerobic counts increased to >2.7 × 10⁵ CFU g⁻¹ (day 21). Product showed acceptability. Results suggest a stable gelled-emulsified type product can be developed from jumbo squid mantle muscle opening a range of possibilities for product development.     

Physicochemical and functional changes in jumbo squid (Dosidicus gigas) mantle muscle during ice storage

Physicochemical and functional changes of jumbo squid (Dosidicus gigas) mantle muscle stored in ice for 15 days were evaluated. Proximate analysis, pH, protein solubility (PS) and SDS-PAGE profile changes were monitored for muscle proteins, while texture profile analysis (TPA) (gel strength, elasticity and cohesiveness), water holding capacity (WHC) and colour changes were monitored for gels produced from this muscle. Fresh muscle chemical composition varied according to fishing season and/or physiological status presented by specimens. pH and PS were stable (p ? 0.05) throughout the study with a slight tendency to decrease towards the end of study. SDS-PAGE revealed no drastic changes in proteins influencing gelation (i.e., myosin). TPA and WHC of gels decreased towards the end of experiment; however, due to sampling variability, no significant differences (p ? 0.05) were found over storage time. Changes in gel colour were observed with hue angle decreasing towards yellow hues. Improved post-capture management of mantle muscle preserved its integrity and functionality for up to two weeks.     

Effects of xylooligosaccharides and sugars on the functionality of porcine myofibrillar proteins during heating and frozen storage

The gel properties of mixed gels of salt-soluble proteins (SSP) and xylooligosaccharides (XOS) or other sugars were investigated. Furthermore, the water-holding capacity, synaeresis, and protein surface hydrophobicity of heated SSP/sugar mixed gels under frozen storage were evaluated. Addition of XOS and sugars lowered expressible moisture and thus elevated the water-holding capacity of mixed gels. The protein surface hydrophobicity (RSo) of heated (71.1 °C) XOS-added gels was lower than that of other treatments, indicating possible lower exposure of protein hydrophobic groups. Results from freeze/thaw stability and protein solubility showed a descending pattern of SSP/sugar mixed gels during frozen storage, with XOS-added gels being better in both test items than other treatments. Increasing saccharide levels improved freeze/thaw stability and protein solubility of frozen mixed gels. Addition of xylooligosaccharides resulted in the lowest RSo among treatments and appears to impact better cryoprotective function to meat proteins than other sugars.     

Effect of frozen storage on emulsifying properties of actomyosin from mantle and fins of squid (<Emphasis Type="Italic">Illex argentinus</Emphasis>)

The emulsifying properties of actomyosin (AM) of mantle and fins obtained periodically from frozen-stored squid were investigated. Oil in water (O/W) emulsions and their stability were studied by optical characterisation. Both emulsions showed that the initial backscattering (BS) decreased after 3 months of frozen storage. O/W emulsions formulated with AM of squid mantle showed certain stability during the first 20 min, and presented destabilisation during the remaining analysed time, reaching a 20% of BS, approximately. However, for emulsions formulated with AM of fins, the BS diminution was recorded between 30 and 45 min, indicating a higher stability as a function of time with respect to the mantle. The size distribution of emulsions prepared after short times of storage presented three droplet size populations. With increasing the time of frozen storage, the size distribution changed from trimodal to bimodal: the large population decreased until it disappeared and the population with medium size increased at long time of frozen storage. The emulsions formulated with AM of squid fins presented a similar behaviour than emulsions of mantle. QuickScan profiles allowed discriminating creaming and coalescence processes to both emulsions mainly at short time of frozen storage. The emulsion prepared with AM from squid fins was further flocculated than emulsion of mantle. Actomyosin from fin squid exhibits the best properties as emulsifier agents of O/W emulsions. These results suggest that a short frozen-storage period can favour the emulsifying properties of actomyosin obtained from squid mantle and fins. On the other hand, the structure of flocs would affect positively the stability of emulsions.     

Effect of ionic strength on soluble protein removal from giant squid mantle (Dosidicus gigas) and functional evaluation of protein recovery

Myofibrillar protein are the principally responsible of gelling properties in fishery resource, hence, during protein concentrate or isolated proteins preparation, sarcoplasmic protein are discarded; however, myofibrillar protein can support low levels of sarcoplasmic proteins without affecting the gelling property. Therefore, the aim of this study was to gradually remove sarcoplasmic proteins from giant squid mantle by means of different ionic strengths (I). Solutions of NaCl with different ionic strengths (I=0.0, 0.1, and 0.3) were used to obtain 3 protein concentrates. The electrophoretic profile in SDS-PAGE showed differences in protein removal with a high solubility of mantle proteins. The texture profile analysis showed that hardness increased in mantle protein washed with higher I. The total reactive sulfhydryls showed significant changes (p<0.05) detecting major formation of S-S bonds with protein removal at an I of 0.3. Differential scanning calorimetry showed a minor denaturation temperature of the actomyosin complex when protein removal was performed with an I of 0.3. The present study indicates that removal of sarcoplasmic protein as a function of I results in better quality gels.     

Ultrastructural and rheological changes during the gelation of giant squid (Dosidicus gigas) muscle

The giant squid or dosidicus (Dosidicus gigas) is normally shipped frozen from the coasts of America. During the period prior to freezing-when conditions are not always optimum-and during frozen storage, the functional capacity of the muscle proteins declines, rendering the material useless for certain processes such as conversion to gel. This paper examines the reasons for the lack of a good gel-forming capacity as measured both rheologically (breaking force, breaking deformation and gel strength) and in terms of ultrastructure (scanning microscopy). The study was carried out at four different temperatures known to be critical for fish muscle protein gel formation, and at two salt concentrations. At 35°C the structure was spongier in gels made with 1.5% NaCl, although a true gel was still not formed, as shown by rheological measurements. Above 30°C, the ultrastructure became more cellular, particularly in samples made with 2.5% NaCl, at which concentration gel strength values were higher. However, at neither salt concentration nor at any of the experimental temperatures was the mesh as spongy as in other fish gels reported in the literature. The values of rheological analysis and folding test were correspondingly low.     

Ultrastructural and rheological changes during the gelation of giant squid (Dosidicus gigas) muscle

The giant squid or dosidicus (Dosidicus gigas) is normally shipped frozen from the coasts of America. During the period prior to freezing-when conditions are not always optimum-and during frozen storage, the functional capacity of the muscle proteins declines, rendering the material useless for certain processes such as conversion to gel. This paper examines the reasons for the lack of a good gel-forming capacity as measured both rheologically (breaking force, breaking deformation and gel strength) and in terms of ultrastructure (scanning microscopy). The study was carried out at four different temperatures known to be critical for fish muscle protein gel formation, and at two salt concentrations. At 35°C the structure was spongier in gels made with 1.5% NaCl, although a true gel was still not formed, as shown by rheological measurements. Above 30°C, the ultrastructure became more cellular, particularly in samples made with 2.5% NaCl, at which concentration gel strength values were higher. However, at neither salt concentration nor at any of the experimental temperatures was the mesh as spongy as in other fish gels reported in the literature. The values of rheological analysis and folding test were correspondingly low.     

Chymotrypsin isolation from jumbo squid (<Emphasis Type="Italic">Dosidicus gigas</Emphasis>) hepatopancreas: Partial characterization and effect on muscle collagen

Chymotrypsin was purified from jumbo squid hepatopancreas (HP) with 2.4-fold and yield 1.9%, and characterized with a molecular weight of 31 kDa, as estimated by sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE). Chymotrypsin effect over collagen extracted from the mantle, fins and arms of the jumbo squid was evaluated. The enzyme exhibited the maximum activity at pH 7 and 65°C using Suc-Ala-Ala-Pro-Phe-p-nitroanilide (SAAPNA) as a substrate and it was identified using the specific inhibitors N-tosyl-L-phenylalaninechloromethyl ketone (TPCK) and phenyl methyl sulfonyl fluoride (PMSF), showing residual activities of 6% and 0%, respectively. Furthermore, high activity was observed in the pH range of 4.0 to 8.0. Purified enzyme showed a moderate in vitro activity using muscle collagen as a substrate. Although further research is needed, the results suggest that the enzyme has a potential application where acidic or slightly alkaline conditions are needed.     

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

Collagen 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.     

3 种鱿鱼冻藏过程中肌原纤维蛋白功能特性变化

为探讨阿根廷鱿鱼、北太平洋鱿鱼（以下简称北太鱿鱼）和秘鲁鱿鱼冻藏过程中肌原纤维蛋白功能特性的变化情况。将3 种鱿鱼于－18 ℃冰箱中冻藏,分别于0、15、30、45、60、75、90、105 d和120 d进行取样,分析测定鱿鱼肌肉中肌原纤维蛋白质量浓度、溶解性、浊度、乳化能力、Ca2＋-ATPase活力、起泡性及泡沫稳定性、羰基含量和总巯基含量等。结果表明,与未冻藏（0 d）相比,经冻藏120 d后,阿根廷鱿鱼、北太鱿鱼、秘鲁鱿鱼肌原纤维蛋白浊度、羰基含量明显增加;其中,肌原纤维蛋白浊度分别增加至1.303、0.608和1.177,羰基含量分别增加了8.74、13.95 nmol/mg和4.79 nmol/mg。肌原纤维蛋白质量浓度、溶解性、起泡性、泡沫稳定性、乳化活性指数（emulsification activity index,EAI）、乳化稳定性指数（emulsification stability index,ESI）、Ca2＋-ATPase活力和总巯基含量则明显下降,其中阿根廷鱿鱼肌原纤维蛋白质量浓度、溶解度、Ca2＋-ATPase活力和总巯基含量冻藏120 d后依次下降72.22%、69.68%、93.07%和76.66%。冻藏120 d后,阿根廷鱿鱼、北太鱿鱼和秘鲁鱿鱼肌原纤维蛋白的EAI分别下降了10.09、15.48 m2/g和11.63 m2/g,其ESI下降趋势与EAI下降趋势基本一致。北太鱿鱼肌原纤维蛋白起泡性和泡沫稳定性下降较为明显,冻藏120 d后,分别下降了60.00%和8.89%,下降速率明显高于阿根廷鱿鱼和秘鲁鱿鱼。综上,在低温冻藏过程中,3 种鱿鱼肌肉中肌原纤维蛋白理化特性表现出类似的变化趋势,但不同理化特性下降幅度及速率有所不同。     

CHANGES IN MYOFIBRILLAR PROTEINS AND LIPIDS OF SQUID (ILLEX ARGENTINUS) DURING FROZEN STORAGE

The biochemical properties of actomyosin (AM) and lipid composition of the mantle from frozen‐stored whole squid were investigated. Irrespective of the sex of specimens, during the first months of storage, there was a trend of decreased protein solubility, reduced viscosity and enzymatic activities of AM. A significant decrease (P < 0.05) in the relative percentage of the myosin heavy chain and a significant increase (P < 0.05) in those of paramyosin and the 155‐kDa component were also observed. After freezing, phospholipids (PL), sterols (ST) and triacylglycerols (TAG) represented 38.6, 29.1 and 21.2%, respectively, of total lipids (TL) from the mantle of male squid. Free fatty acids (FFA) plus diacylglycerols constituted only 11% of TL. TL extract from the mantle of female squid had a higher percentage of PL and had lower ST. In the frozen‐stored male and female squid, TAG were hydrolyzed earlier than PL. At zero time of storage, the relative percentages of saturated and unsaturated fatty acid in TL extracts from the mantle of male and female squid were 39.1, 59.2 and 38.7, 61.1, respectively. Irrespective of sex, the saturated FA fraction significantly (P < 0.05) decreased and the unsaturated one significantly (P < 0.05) increased after 8 months of frozen storage.     

Comparative Study of Washing Treatments and Alkali Extraction on Gelation Characteristics of Striped Catfish (Pangasius hypophthalmus) Muscle Protein

ABSTRACT:  The effect of washing treatments (water and alkali washing) and alkali extraction/acid precipitation on the physicochemical and textural properties of striped catfish ( Pangasius hypophthalmus ) muscle protein was compared. Alkali extraction/acid precipitation process resulted in the highest protein recovery of 98.77% (dry weight basis) and lowest fat content of 0.98% (dry weight basis). The extractable proteins of fish protein isolates (FPI) at various ionic strengths (0 to 0.6 M NaCl) exhibited majority of protein at 38 kDa with trace amount of others. Unsaturated fatty acids, namely, oleic, linoleic, and docosahexaenoic acid, were greatly reduced in FPI. Water-washed mince (W) exhibited higher autolytic activity than mince (M), suggesting the presence of myofibril-bound proteinase(s). Autolytic activity was lowest in the FPI. Breaking force of striped catfish gels was greatly improved when set at 40 °C for 30 min, regardless of preparation treatment. The typical water washing process was effective to improve gel-forming ability of striped catfish. FPI gels contained the lower total sulfhydryl content, indicating the greater extent of disulfide bond formation as compared to that of washed mince. The FPI gels showed higher breaking force but lower deformation values than W and alkali-washed (AW) gels. Addition of NaCl improved deformation, but adversely affected breaking force of FPI gel. Whiteness of FPI gel increased with NaCl addition.     

Frozen storage of minced prawn flesh: effect of sorbitol, egg white and starch as protective ingredients

 The functionality of minced prawn flesh during frozen storage, with and without added ingredients as protectants, was examined in terms of water-holding capacity, protein solubility, viscosity, texture and gel-forming capacity. Different lots containing sorbitol, egg white and starch were studied. Minced prawn showed high protein solubility which remained constant after 3 months of frozen storage, regardless of the ingredients used. A slight increase in shear strength during the storage period was suppressed by the addition of ingredients; however, these were not effective at substantially improving the gel-forming capacity of the minced prawn. Viscosity was the property most affected by frozen storage, and was improved by the addition of ingredients.     

Jumbo squid (Dosidicus gigas) myofibrillar protein concentrate for edible packaging films and storage stability

Properties and storage stability of two different jumbo squid myofibrillar protein-based films were investigated. Myofibrillar proteins were extracted by isoelectric precipitation after acidic and alkaline solubilization, obtaining the same extraction yield. During extraction the edible fraction, which was discarded during mantle skinning, was recovered, and the fishy flavour produced by nitrogen and other undesirable compounds was removed, although some sarcoplasmic proteins were lost simultaneously. In alkaline-Concentrate (C), myosin unfolding led to water resistant films, less water vapour permeable and more mechanically resistant than acidic–Films (F); whereas acidic-C protein hydrolysis resulted in more transparent and soluble films, with higher protein release (∼80 g/L). During 4 months of storage some structure reorganization occurred, and both films incremented their yellowish tendency, especially the acidic-F, being this attributed to a Maillard reaction with plasticizers. After storage time, water solubility increased in C-films. While acidic-F aggregation led to a protein release reduction and tensile strength improvement, alkali-F became weak and brittle, loosing transparency. C-films offered different filmogenic properties, proving to be promising biodegradable packaging materials.     

Postmortem biochemical behavior of giant squid (Dosidicus gigas) mantle muscle stored in ice and its relation with quality parameters

ABSTRACT:  Several freshness and spoilage indicators were monitored to characterize the postmortem biochemistry of giant squid ( Dosidicus gigas ) mantle muscle. Squid samples were obtained directly from the sea and kept at 0 °C during a 15-d storage period. Data at zero time were obtained from cryogenically frozen samples at time of capture. The adenosine 5'-triphosphate (ATP) degradation followed a different pattern as compared with that from fish species. ATP was almost completely depleted at 24-h postcatch from 6.54 to <1 μmol/g, while at the same time Hx was the predominant catabolite with a concentration of 4 μmol/g, reaching 6.85 μmol/g at day 15. K -value data followed a logarithmic pattern with time instead of a linear one, with no change after day 3, thus reducing its suitability as a freshness index. The coefficient Hx/AMP seems to be an adequate alternative for this purpose due to its constant increment with time. The high NH₄Cl content in mantle muscle (461.3 ± 24.5 mg of NH₄⁺/100 g) derived from its physiological importance for the species compromises the use of the distillation step of the TVB-N analysis commonly used as a spoilage index. This fact explains why the initially high value of TVB-N detected in mantle muscle (243.7 mg N/100 g) did not correlate with the initial low TMA-N content (1.5 ± 0.1 mg/100 g of muscle). The results suggested that under the experimental conditions the shelf life of squid exceeds 15 d.     

不同抗冻剂对鱿鱼滑冻藏期间品质特性的影响

为了提高冷冻鱿鱼滑制品品质的稳定性,本研究以秘鲁鱿鱼为原料,通过测定鱿鱼滑的凝胶强度、持水性、水分分布状态、Ca²⁺-ATPase活性和微观结构等指标,探究不同添加量的海藻糖(2%、4%、6%)、乳糖醇(2%、4%、6%)和乳酸钠(2%、3%、4%)对鱿鱼滑在冻藏150 d的冷冻保护作用及其品质的影响。结果表明,随着添加量的增加,海藻糖、乳糖醇和乳酸钠均能显著提高鱿鱼滑在冻藏期间的凝胶强度和持水性(P<0.05)。在冻藏150 d后,6%海藻糖、6%乳糖醇和4%乳酸钠组鱿鱼滑Ca²⁺-ATPase活性分别为0.28、0.26和0.30μmol Pi/(mg prot·h),显著高于空白组0.17μmol Pi/(mg prot·h)(P<0.05),延缓了鱿鱼滑肌原纤维蛋白的变性程度。电镜扫描图(SEM)显示,随着冻藏时间的延长,相比乳糖醇组及空白组,添加6%海藻糖和4%乳酸钠的鱿鱼滑微观组织较为紧密,较好地保持了鱿鱼滑的凝胶网络结构。结合感官评定,添加6%海藻糖能够提高冻藏后鱿鱼滑的口感和整体接受度。综上,6%海藻糖可有效延缓鱿...     

Comparison of the properties of gels derived from cod surimi and from unwashed and once-washed cod mince

Surimi is a washed and stabilized fish mince with valuable gel-forming properties. However the preparation process is wasteful and a modified process, with less washing, was investigated. The properties of the gels (cooked at 40°C for 30 min followed by 90°C for 40 min) were assessed by instrumental and sensory methods. Gels prepared from surimi were soft and very flexible; gels from unwashed fresh cod mince were firmer and less elastic, but still gave a maximum score on the folding test. A single wash made the gels firmer and slightly more elastic than those from unwashed mince. Gels from unwashed mince of frozen cod were firmer than surimi-derived gels, and were the most brittle. Sensory assessment of the gels found no difference in firmness between the different washing procedures and small differences in elasticity and toughness. The addition of starch (fish: starch, 100:5, w/w) increased the firmness and sensory toughness of each derived gel, and reduced the elasticity in the mouth of non-surimi gels. The colour of gels derived directly from fish was off-white, compared with the white surimi-derived gels. The colour of the former darkened during frozen storage, but lightened again after thawing.     

Effect of heating temperature and sodium chloride concentration on ultrastructure and texture of gels made from giant squid (Dosidicus gigas) with addition of starch,l-carrageenan and egg white

This paper seeks to compare the ultrastructure of gels made from frozen muscle of giant squid (Dosidicus gigas) at various temperatures with a number of different rheological parameters, with reference to a variety of added ingredients (non-muscle proteins and hydrocolloids) and to NaCl concentration. Interesting data on gel rheological properties were found where formulae containedl-carrageenan, starch and egg white, with a low salt concentration (1.5%). This seems to be because carrageenan forms an independent network which supports the principal structure formed by the fish protein; starch is incorporated into the network and retains water; and egg white forms a supplementary network which helps to improve rheological properties.