Effects of Partial and Complete Replacement of Synthetic Cryoprotectant with Carrot (Daucus carota) Concentrated Protein on Stability of Frozen Surimi

ABSTRACT

The study aimed to evaluate the effects of carrot concentrated protein (CCP) as additive on the functional and textural properties of surimi from striped catfish (Pangasianodon hypophthalmus) during six months of frozen storage (?20°C). The CCP (82.22% crude protein) was used as an additive either a lone or with a synthetic cryoprotectant (sucrose-sorbitol-sodium tri-polyphosphate). Control was made with synthetic cryoprotectant only. Molecular weight of CCP was found to be 36 kDa. After six months, the results revealed that up to 50% of synthetic cryoprotectants could be replaced by CCP during frozen storage of surimi. Biochemical parameters such as protein solubility, Ca²⁺ATPase activity, and gel strength decreased significantly (p < .05) during storage. Treatment T-3 (CCP 0.5% + 50% of synthetic cryoprotectant) maintained quality of protein significantly superior (p < .05) in respect to denaturation and other functional and sensory attributes compared to all the treatments. The microstructure images of surimi confirmed that addition of CCP modified the ice crystal growth during frozen storage. This study suggests that CCP can be a potential additive to protect protein from denaturation along with partial replacement of chemical cryoprotectants.     

Physicochemical and Gel Properties of Myofibrillar Protein from Sin Croaker (Johnius dussumieri) Fish During Ice Storage

The physicochemical and gel properties of myofibrillar protein (MFP) from sin croaker fish were studied during ice storage for 18 days. Significant changes in the trends of solubility, Ca²⁺ ATPase enzyme activity, surface hydrophobicity, and water holding capacity of extracted MFP were observed by the 6th day of storage. The Ca²⁺ ATPase enzyme activity reduced significantly (p < 0.05) by the 6th day of storage. However, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) did not show a remarkable change in the concentration of myosin heavy chain. Surface hydrophobicity increased almost four times from its original value of 18.98 µg; whereas, water holding capacity showed a fluctuating trend during storage. The emulsion capacity of the MFP was in the range of 0.89- to 1.92-mL oil/mg protein during storage. The gel strength value (313.45 g.cm) of heat-induced gel prepared from fresh minced meat decreased significantly (p < 0.05) by the 6th day of ice storage. Texture profile analysis revealed that changes in hardness and gumminess were concurrent to steeply reducing breaking force up to the 6th day. The histological observation showed gradually increasing gaps between muscle fibers. The histological observations and physicochemical quality indicated that the sin croaker fish can be used for producing good quality surimi when stored for up to 6 days in ice.     

Myosin denaturation in heated myofibrils of scallop adductor muscle

The thermal inactivation of Ca²⁺ ATPase of scallop myofibrils (0.1 M KCl, pH 7.5) was found to be unaffected by the presence of Ca²⁺. Monomeric myosin content and salt solubility decreased much faster than Ca²⁺ ATPase inactivation in both Ca and EDTA media, which was well explained by faster denaturation of the rod portion than subfragment-1 of myosin. In contrast, when the myofibrils were heated at 0.5 M KCl, a slow decrease in salt solubility was observed, which was also explained by slow denaturation of the rod portion of myosin. Myofibrils from scallop smooth muscle showed the same denaturation pattern as those from adductor muscle. These results show that mollusk myosin is not always stabilized by Ca²⁺.     

Setting Ability of Threadfin Bream (Nemipterus japonicus) Meat as Affected by Freezing and Frozen Storage with Special Reference to Transglutaminase Enzyme Activity and Rheological Properties

The effect of freezing and frozen storage of threadfin bream fish (Nemipterus japonicus) meat on the setting and gel-forming ability has been evaluated. The dynamic viscoelastic properties of fish meat during setting and thermal gelation process were evaluated using Controlled Stress Rheometer under oscillatory mode. A sharp decrease in setting ability was recorded immediately after freezing as revealed by storage modulus (G?) values. The transglutaminase (TGase) enzyme activity of fish meat decreased from the initial value of 81.09 to 51.46 U/g meat/min at the end of 200 days of frozen storage. A decrease in setting ability of fish meat beyond 160 days of frozen storage is probably related to lower TGase enzyme activity. The gel-forming ability was related to setting ability during the frozen storage period. Although the protein solubility showed a decreasing trend during 200 days of frozen storage, the decrease was not significant. The effect of freezing and frozen storage on calcium-activated adenosine triphosphatase (Ca²⁺-ATPase) enzyme activity of fish mince was significant (P < 0.05). A reduction in protein solubility and Ca²⁺-ATPase enzyme activity is an indication of aggregation/denaturation of myofibrillar proteins.     

虾夷扇贝闭壳肌和外套膜肌原纤维蛋白的特性分析

为探索采捕后活品虾夷扇贝品质变化与其肌肉蛋白质生理特性变化间的关联,本研究以虾夷扇贝2个可食部肌肉为研究对象,以肌原纤维蛋白ATPase活性为指标(Ca²⁺-ATPase,Mg²⁺-ATPase),对扇贝肌原纤维蛋白(Mf)的稳定性进行了系统探索。首先,分别提取闭壳肌肌原纤维(A-Mf)和外套膜肌原纤维(M-Mf);然后,考察了不同因素(离子强度I、pH、温度)对Mf的ATPase活性的影响规律;对A-Mf及M-Mf的稳定性进行了探索;进一步比较了闭壳肌和外套膜肌原纤维蛋白ATPase的失活特性。研究结果表明:(1)虾夷扇贝闭壳肌与外套膜的Mf的理化性质相似,A-Mf与M-Mf的pI均在5.0附近,粘度分析发现A-Mf热稳定性高于M-Mf。(2)ATPase活性变化规律的结果发现,与脊椎动物中的鱼类一样,作为无脊椎动物的扇贝,与Mg²⁺-ATPase相比,Ca²⁺-ATPase更能准确地反映Mf的稳定性。(3)闭壳肌和外套膜二者的Mf的Ca²⁺-ATPase呈现出共同特性,在pH为中性时活性最高;A-Mf与M-Mf的差异性则表现为前者的Ca²⁺-ATPase在较低离子强度(I=0.2)下活性最高,后者则在较高离子强度(I=0.5)下活性最高;离子强度对A-Mf的热稳定性影响不明显,而M-Mf的热稳定性明显受到离子强度的影响,其在较低离子强度下表现出更好的稳定性。(4)Ca²⁺-ATPase失活速率的研究发现,无论是闭壳肌还是外套膜,其稳定性与离子强度I和温度均呈现显著正相关(R²=0.8181、0.8436和R²=0.9887、0.9557);二者在pH 7.0左右的稳定性最好,偏离中性会促使Ca²⁺-ATPase失活,与碱性条件相比,酸性对蛋白质稳定性的破坏更加明显。     

Effect of Cryoprotectants on Suppression of Protein Structure Deterioration Induced by Freeze-thaw Cycle in Pacific White Shrimp

This study aimed to elucidate the changes in Pacific white shrimp (Litopenaeus vannamei) myofibrillar protein as influenced by multiple freeze-thaw cycles as well as the stabilization effects of sucrose and trisodium citrate on shrimp myofibrils. Shrimp myofibrils in 0.1 M NaCl, 20 mM Tris-HCl (pH 7.5) were mixed individually with sucrose and citrate at concentrations of 0.05 M and were evaluated for Ca²⁺-ATPase activity, salt solubility, total and reactive sulfhydryl, and surface hydrophobicity during three freeze-thaw cycles. Sucrose and citrate had strong cryoprotective effects against freeze denaturation by retaining higher Ca²⁺-ATPase activity and salt-soluble myosin and actin, by slowing the reduction of reactive sulfhydryl (SH) and by exposing less hydrophobic groups at the surface of the protein compared with the no-additive sample. Results indicated that both cryoprotectants had suppressive effect against protein denaturation and helped stabilize white shrimp myofibrillar protein during the freeze-thaw process. This study suggests that sucrose and citrate stabilized the protein structure by retarding the unfolding of protein; thus, the native protein could be protected during frozen storage.     

Changes in Protein Oxidation,Water-Holding Capacity,and Texture of Bighead Carp (Aristichthys Nobilis) Fillets Under Chilled and Partial Frozen Storage

This study aimed to evaluate the contribution of protein oxidation to the changes in the water-holding capacity (WHC) and texture of bighead carp (Aristichthys nobilis) fillets under chilled and partial frozen storage (4°C and ?3°C). The results indicated that less protein oxidation occurred to fillets at ?3°C than at 4°C, which was reflected by the higher value of salt-soluble protein contents (SSP), total sulfhydryl content (SH), Ca²⁺-ATPase activity, lower water-soluble protein contents (WSP), total disulfide content (SS), and surface hydrophobicity (So-ANS). However, the fillets had better WHC and texture at 4°C, as well as lower drip loss and higher centrifugal loss, hardness, and springiness. A significant linear relationship existed between protein oxidation parameters with WHC and texture characteristics for fillets under both types of storage, but the process of freezing and then thawing, instead of protein oxidation, was the main factor affecting the texture and WHC of fillets at ?3°C.     

Effects of ambient ion concentrations on gill ATPases in fresh water eel,Anguilla anguilla

Branchial activities of Na⁺,K⁺-ATPase (ouabain sensitive), Mg²⁺ ATPase (ouabain insensitive) and kinetic analysis of high and low affinity Ca²⁺ ATPase were measured inAnguilla anguilla that had been acclimated to demineralized water (DW, Ca < 10 M), freshwater (FW, Ca = 2 mM), and Low calcium freshwater (L-Ca, Ca = 0.9 mM). Na⁺,K⁺-ATPase activity decreased while ouabain insensitive activity increased when ambient Ca²⁺ decreased. Two kinetic forms of Ca²⁺ ATPase could be resolved in each environmental condition. The stimulation coefficients of both sites or enzymes were not affected by ambient Ca²⁺ concentrations. The maximal velocity of both the high and the low affinity Ca²⁺ ATPase was increased when external Ca²⁺ was decreased during acclimation. The low affinity Ca²⁺ ATPase and the Mg²⁺ stimulated enzyme could be a non specific enzyme accepting either Ca²⁺ or Mg²⁺. Results are compared with previous results in the literature and in relation to the branchial morphology and ionic exchanges in fish.     

Ca2+- and Mg2+-Induced Conformational and Rheological Changes of Actomyosin Extracted from Fresh and Freeze-Thaw Tilapia

ABSTRACT

The conformational changes of natural actomyosins prepared from fresh and freeze-thaw tilapia (Oreochromis niloticus) in the presence of Ca²⁺ or Mg²⁺ were investigated. The Ca²⁺-activated adenosine triphosphatase (Ca²⁺-ATPase) activities of actomyosins extracted from fresh and freeze-thaw fish were comparable (p > 0.05). The denaturation temperatures (T_d) of actomyosins extracted from fresh fish were lower than those from freeze-thaw counterparts (p < 0.05). The addition of Ca²⁺ or Mg²⁺ reduced the T_d of actomyosins. Ca²⁺ and Mg²⁺ enhanced protein aggregation at ≥ 40°C (p < 0.05). Based on the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) pattern, the myosin heavy chain (MHC) and actin bands tended to form large aggregates to a greater extent in the presence of 100mM Ca²⁺ or Mg²⁺. Ca²⁺ and Mg²⁺enhanced disulfide linkages and hydrophobic interactions among actomyosin molecules. The onset temperature of elastic modulus (G′) of both actomyosins was shifted to lower temperature as 100mM of Ca²⁺ or Mg²⁺ was added. Mg²⁺ at 20mM increased the breaking force of washed tilapia mince at 40°C. Our results revealed that the intrinsic properties of actomyosins extracted from fresh and frozen fish were distinct, and divalent ions Ca²⁺ or Mg²⁺ affected their gelation differently.     

Three-Way Modelling of NMR Relaxation Profiles from Thawed Cod Muscle

Abstract

Low-field ¹ H nuclear magnetic resonance transverse relaxation was used to measure water mobility and distribution in cod stored at ?20°C or ?30°C for up to 12 months and subsequently from 0 to 21 days in modified atmosphere at +2°C. The relaxation profiles were decomposed by parallel factor analysis resulting in four first-order relaxation curves from which the relative water pool sizes and the transverse relaxation times (T2) were calculated. The T2-values of the four identified water pools were 37 ms, 56 ms, 126 ms and 361 ms, respectively. The relative size of the water pools, but not the relaxation times, depended on the frozen storage temperature and on the chilled storage period.     

Effects of High Pressure on Myofibrillar Protein and Moisture Distribution of Shrimp (Solenocera melantho) Muscle

ABSTRACT

The effects of high pressure (100–500 MPa) treatment on myofibrillar protein (MP) contents and distribution of water in Solenocera melantho muscle were investigated. The results showed that the shrimp treated with 200 MPa had the highest shelling score, and the solubility of MP in meat of shrimp treated with 300 MPa was significantly reduced. Moreover, the surface hydrophobicity of MP increased with increasing pressure. Treatment of shrimp with 200–300 MPa high pressure partially converted the structure of MP from an α-helix structure to a β-sheet structure, allowing for greater exposure of the tryptophan residues present. Treatment of shrimp with 100–200 MPa led to a significant loss in the amount of immobilized water in shrimp muscle. However, the treatment did not significantly change the moisture distribution. Overall, pressures of 100 to 200 MPa are considered the most suitable for the processing of S. melantho.     

High Pressure Processing and Water Holding Capacity of Sea Bass Skeletal Muscle

The water holding capacity (WHC) and relationship between protein denaturation and WHC of sea bass skeletal muscle (SBSM) with high pressure (HP) treatment were investigated up to a pressure level of 600 MPa. The results showed that it had the lowest cooking loss (CL) at 200 MPa, and CL value decreased 20.9% compared with 0.1 MPa. Additionally, 400 MPa produced the highest water retention, and 0.1 MPa produced the lowest water retention by low field-nuclear magnetic resonance (LF-NMR). The WHC was related to protein denaturation. Examination of extracted proteins using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and protein solubility indicated that high pressure resulted in protein denaturation; the differential scanning calorimetry (DSC) curve showed the myosin peak reduced significantly at 400 MPa and was eliminated at 600 MPa, while the actin peak was eliminated at 300 MPa; morphology of sarcoplasmic proteins were sponge-like at 200 MPa, which was conducive to enhancing WHC.     

Quality of Filleted Atlantic Mackerel (Scomber Scombrus) During Chilled and Frozen Storage: Changes in Lipids,Vitamin D,Proteins, and Small Metabolites,including Biogenic Amines

Quality changes of vacuum-packed Atlantic mackerel (Scomber scombrus) fillets during 12 months’ frozen storage at ?27°C and 9 days’ chilled storage at +4°C were evaluated. Freezing at ?27°C preserved the long chain n-3 polyunsaturated fatty acids (LC n-3 PUFAs), both in light and dark muscle, vitamin D, and the low molecular weight metabolites (LMW) (studied by high resolution nuclear magnetic resonance spectroscopy, HR NMR). Protein oxidation took place, especially between 1 and 7 months, decreasing water holding capacity and protein extractability. During chilled storage, no lipid or protein oxidation was observed, but lipolysis increased, and several LMW metabolites relevant for sensory and nutritional quality degraded into non-favorable compounds. The content of biogenic amines was high at day 9 (e.g., 18 mg histamine/100 g), jeopardizing safety. Preservation of mackerel fillets by freezing at ?27°C is thus a better option compared to prolonged chilled storage at +4°C; the quality was well preserved for 12 months’ frozen storage.     

Chilled Storage of High Pressure Processed Black Tiger Shrimp (Penaeus monodon)

The effect of high pressure (HP) treatment (at 100, 270, and 435 MPa for 5 min at 25°C) on microbiological (total viable count and total psychrotrophic count), physical (color, texture, and drip loss), and microstructural characteristics of black tiger shrimp (Penaeus monodon) during storage at 2°C for 35 days was investigated. Pressure treatment increased drip loss, maintained low microorganisms level, imparted cooked appearance to the muscle, and resulted in improved texture. Results of scanning electron microscopy revealed more compact structure in treated samples, confirming the results of texture profile analysis. Pressure treatment of 435 MPa was most effective in preserving the quality of shrimp.     

Relationship between Lipid Oxidation,Protein Function Properties,and Freshness Changes of Salt-Treated Blunt-Snout Bream (Megalobrama amblycephala) Fillets Stored at 4°C

The aim of this study was to investigate the relationship between lipid oxidation, protein function properties, and freshness changes of blunt-snout bream (Megalobrama amblycephala) fillets treated with 2% and 4% salt during storage at 4°C. Salting with 2% and 4% salt could delay quality deterioration and protein denaturation, thus improving sensory attributes to some extent. But, 4% salt promoted lipid oxidation of blunt-snout bream fillets. There is a significant correlation (p < 0.05) between freshness indexes and lipid oxidation or protein function properties (total SH content, Ca²⁺-ATPase activity). Salting with 2% salt is an ideal treatment to control the quality of blunt-snout bream fillets stored at 4°C.     

The Influence of Cooking Parameters and Chilled Storage Time on Quality of Sous-Vide Atlantic Mackerel (Scomber scombrus)

The aim of the present study was to evaluate the effects of various sous-vide time–temperature regimes and their interactions on quality parameters of Atlantic mackerel (Scomber scombrus) during chilled storage. The mackerel ?llets were exposed to sous-vide treatment at 60, 75, and 90°C for 10, 15, and 20 min and further stored for 1, 3, and 7 days at 4 ± 1°C before analysis. Changes in pH, water content and cook loss, amount of water- and salt-soluble proteins, texture, and color parameters, as well as accumulation of lipid oxidation products in sous-vide-cooked mackerel were assessed. Sous-vide cooking time and temperature had the lowest contribution to the formation of primary and secondary products of lipid oxidation, as well as increase in yellowness of the fish flesh due to their accumulation; whereas duration of chilled storage led to a significant increase in oxidation and yellowness (p < 0.05). Duration of chilled storage also affected structural and textural properties of the fish muscle, leading to a decreased cook loss. At the same time, sous-vide cooking decreased the firmness of the fish muscle. Duration of chilled storage was found to have the highest significant effect (p < 0.001) on all physicochemical characteristics of sous-vide-cooked mackerel.     

Effects of High Pressure Treatment on Physicochemical Quality of Pre- and Post-Rigor Palm Ruff (Seriolella Violacea) Fillets

Fish and fish products are characterized for having a short shelf life. Nonthermal processing techniques such as high hydrostatic pressure (HHP) have increasingly been employed to extend shelf life of food products. The aim of this study was to evaluate changes on flesh physicochemical spoilage parameters (pH, total volatile bases (TVB-N), trimethylamine (TMA), thiobarbituric acid (TBA), and color) of palm ruff (Seriolella violacea) fillets in pre- and post-rigor conditions, subjected to two different HHP conditions: 450 MPa and 550 MPa, for 3 and 4 min each. Unpressurized and pressurized fillets were kept in chilled storage (4 ± 1°C) for 26 days to assess the effect of HHP on shelf life. pH and TBA values increased after HHP treatment and with storage time for both unpressurized and pressurized samples. This is attributable to pressure-induced lipid oxidation. Lightness (L*) values increased with pressure, where fish fillets had a cooked appearance. TMA and TVB-N values decreased after HHP treatment compared to the unpressurized samples, showing that HHP treatment is an efficient method to maintain the quality of palm ruff fillets. There was no clear difference between pre- and post-rigor in the parameters evaluated.     

Effects of Drying Condition on Physico-chemical Properties of Foam-mat Dried Shrimp Powder

ABSTRACT

The effects of drying parameters on moisture content, water activity, bulk density, water binding capacity (WBC), oil absorption, and color parameters (L*,a*, b*) of foam-mat dried shrimp powders were investigated. Shrimp purees were dried as a foam mat at different drying temperatures (50ºC, 60ºC, and 70ºC) and thicknesses of the foam layer (4 and 8 mm). The experimental results showed that as the temperature increased, the moisture content, water activity, and oil absorption of the samples decreased. However, their solubility increased significantly (P ?0.05). Bulk density of shrimp powder increased with increasing the thickness of the foam layer. Increasing temperature led to increased and decreased WBC with 4 and 8 mm thickness, respectively. Furthermore, the a*, b*, and L* (at 8 mm thickness) decreased with increasing temperature; however, L* increased at 4 mm thickness. Fourier transform infrared (FTIR) spectra showed some major shifts, such as in the region of 1000–1700 cm^?1, related to C–O, C–O–C, and C–H band stretching. The differential scanning calorimetry thermograms showed a large peak with a denaturation peak around 72ºC for shrimp proteins.     

Textural Changes During Iced Storage of Salmon (Salmo salar) and Cod (Gadus morhua)

Abstract

Textural properties, protein solubility, water holding capacity and activity of collagenolytic enzymes of salmon (Salmo salar) and cod (Gadus morhua) fillets were measured during iced storage. Breaking strength and hardness of fillets were reduced during iced storage. Elasticity of cod fillets was reduced, while cohesiveness of salmon increased during storage. Salmon was softer and less elastic than cod. During storage, total amount of extracted proteins was reduced for cod, and increased followed by a reduction for salmon. The fraction of salt soluble proteins increased during storage, and values for cod were higher than those for salmon. The activity of collagenolytic enzymes was higher in cod than salmon during the whole storage period.