Myofibrillar Protein Solubility of Model Beef Batters as Affected by Low Levels of Calcium, Magnesium and Zinc Chloride

Preblended composites of semimembranosus and adductor muscles were stored 12h at 4°C with 2.0% NaCl, 0 or 0.05% CaCl₂, MgCl₂, or ZnCl₂ and 0 or 0.4% sodium tripolyphosphate (STPP). Model systems were formulated to contain 30% fat (high fat; HF) or 10% fat (low fat; LF). Divalent salts lowered extract pH and ZnCl₂ elicited the greatest reduction. At both fat levels, CaCl₂ increased and ZnCl₂ decreased protein solubility, compared to the control (p<0.05). Myosin was not detected in ZnCl₂-treated HF and LF batters without STPP and in the presence of STPP, MgCl₂ and ZnCl₂ increased myosin concentration at both fat levels (p<0.05). Zinc chloride increased actin concentration in HF batters; whereas, MgCl₂ decreased soluble actin in LF batters (p<0.05). Magnesium chloride (0.05%) increased soluble proteins in LF batters containing 0.4% STPP by increasing myosin extractability.     

Cook Yield, Texture and Gel Ultrastructure of Model Beef Batters as Affected by Low Levels of Calcium, Magnesium and Zinc Chloride

Effects of 0.05% CaCl₂, MgCl₂, or ZnCl₂, with or without 0.4% sodium tripolyphosphate (STPP), were investigated in high fat (HF; 30% fat) or low fat (LF; 10% fat) model beef batters. Cook yield (CY), texture, and gel ultrastructure were evaluated. With STPP, CaCl₂ increased CY, and in the absence of STPP, ZnCl₂ decreased CY and cohesiveness (p<0.05). Low-fat, ZnCl₂-treated batters without STPP had the lowest (p<0.05) hardness. Addition of STPP resulted in a homogeneous matrix in HF batters. In MgCl₂-treated HF batters, protein film surrounding fat globules had greater integrity than control, CaCl₂ or ZnCl₂ treatments. In ZnCl₂-treated HF batters (without STPP) a protein sheet was present without evidence of film encased droplets. Low-fat batters with STPP had finer, more porous networks than those without STPP.     

Influence of Sodium, Potassium and Magnesium Chloride on Thermal Properties of Beef Muscle

Sodium, potassium and magnesium chloride, at 1.25, 2.50 and 5.00%, were studied using differential scanning calorimetry. Increasing NaCl resulted in decrease in myosin transition temperature (T₁, first transition) and enthalpy (H₁); both showed significant (P<0.05) linear response. The sarcoplasmic proteins and collagen denaturation temperature (T₂, second transition) increased significantly over the control when 1.25% NaCl was added, but were the same as control when 2.5% and 5.0% were used. Actin denaturation temperature (T₃, third transition) tended to increase when NaCl was added, but enthalpy decreased. Potassium chloride showed similar effects to NaCl on T₁, T₂, H₁ and H₃. Increasing magnesium chloride had much more pronounced effect on decreasing second enthalpy compared to the monovalent salts. At 5% MgCl₂ T₁ increased significantly.     

Effect of brine salting at different pHs on the functional properties of cod muscle proteins after subsequent dry salting

Fillets of Atlantic cod (Gadus morhua) were wet-salted in brines of pH 6.5 and 8.5 containing different combinations of NaCl, KCl, MgCl₂ and CaCl₂, then dry-salted in NaCl. Proximate analyses, functional properties (water holding capacity and protein solubility) and hardness were determined in the dry-salted cod. The compositions of the protein fractions soluble in water and in 0.86 M sodium chloride were determined by SDS–PAGE. The composition and pH of the brines slightly affected the protein composition of the major extract constituents and the functional properties of the muscle after dry-salting. Brining at alkaline pH produced a larger variety of water-soluble proteins, particularly actin, than at pH 6.5. Furthermore, the compositions of the protein fractions extracted with 0.86 M NaCl were very similar for both pHs, irrespective of the composition of the brine; in this case, myosin heavy chains were absent in both extracts due to aggregation caused by a massive uptake of salt by the muscle.     

Effects of carrageenan on thermal stability of proteins from chicken thigh and breast muscles

Thermal stability of ground chicken meat and myofibrillar proteins mixed with κ-, ι-, and λ-carrageenan (CGN) at different NaCl concentrations was investigated with differential scanning calorimetry. Three transitions, characteristic of myosin head (63.3, 62.2°C), sarcoplasmic proteins/myosin tail (67.7, 68.6°C), and actin (78.3, 81.4°C), were observed for nontreated thigh and breast muscles, respectively. The influence of CGNs on the thermal transitions was dependent on salt concentrations. κ-CGN with 2.5% NaCl decreased (P<0.05) transition temperature (T_max) of thigh myosin head and actin, while all three CGNs with or without 2.5% salt decreased (P<0.05) T_max for breast actin. Total enthalpy of denaturation decreased slightly in the presence of κ-CGN for thigh muscles only. The gum effects on myofibril isolates were variable and were salt-dependent. The results suggested molecular interactions between the gums and meat proteins, but the response of the specific proteins to gums appeared to be muscle type-dependent.     

Use of a D-optimal mixture design to estimate the effects of diverse chloride salts on the growth parameters of Lactobacillus pentosus

The effects of NaCl, KCl, CaCl₂, and MgCl₂ and their mixtures on the ionic strength (IS) of the medium and the growth parameters of Lactobacillus pentosus were studied by means of a D-optimal mixture experimental design with constrains (total salt concentration ≤ 9.0%, wt/vol) and the generalized z-value. The IS was linearly related to the concentrations of the diverse salts and its increase, for similar concentrations of salts, followed the order MgCl₂ > CaCl₂ > NaCl > KCl. Within the experimental region, the lag phase duration (λ) was mainly affected by NaCl and CaCl₂ and the interaction KCl with MgCl₂. The maximum specific growth rate (μ_max) decreased as NaCl (the highest effect), CaCl₂, and MgCl₂ increased (regardless of the presence or not of previous NaCl); low KCl concentrations had a stimulating effect on μ_max, but its overall effect showed a similar trend to the other salts. The maximum population reached (N_max) was the least affected parameter and decreased as NaCl and CaCl₂ concentrations increased regardless of the presence of the other salts. The equations that expressed the growth parameters as a function of the diverse chloride salts, within the limits assayed, were developed and the corresponding z- and harmonic Z-values were estimated.     

Effects of Ca++, Mg++ and Na+ on Heat Aggregation of Whey Protein Concentrates

Effect of Ca⁺⁺ on the heat aggregation of whey protein concentrates (WPC) was compared with that of Na⁺ and Mg⁺⁺. On the alkaline side of the isoelectric zone, aggregation of WPC was increased by the addition of CaCl₂, MgCl₂ or NaCl, among which CaCl₂ showed the greatest effect. The denaturation temperature of WPC determined by differential scanning calorimetry significantly decreased in the presence of CaCl₂ or MgCl₂, but increased slightly in the presence of NaCl. In the electrophoretic patterns of heated WPC, the most sensitive protein to Ca⁺⁺ was β-lactoglobulin.     

Water sorption and time-dependent crystallization behaviour of freeze-dried lactose-salt mixtures

Water sorption properties of freeze-dried lactose, lactose/CaCl₂, lactose/NaCl, lactose/MgCl₂, and lactose/KCl mixtures in their molar ratio of (9:1) were investigated. Brunauer-Emmett-Teller (BET) and Guggenheim-Anderson-de Boer (GAB) models were used to model water sorption properties. Water is known to function as a plasticizer, depressing the glass transition and facilitating crystallization. Crystallization in the present study resulted in loss of sorbed water from lactose. The crystallization of pure lactose and lactose/salt mixtures was observed at RVP?44.0% within 24 h. At RVP?54.4% water contents were higher in lactose/CaCl₂ and lactose/MgCl₂ mixtures than in pure lactose, lactose/NaCl, and lactose/KCl.Water content in pure lactose after crystallization was ?5.0%, suggesting that lactose crystallized as a mixture of α-lactose monohydrate and various anhydrous forms of α/β-lactose crystals. Anhydrous lactose/CaCl₂ and lactose/MgCl₂ had higher glass transition temperatures than lactose, but other salts (NaCl and KCl) with lactose gave lower glass transition than amorphous lactose. It seems that bivalent salts in mixtures with lactose gave a higher T_g than smaller monovalent ions. Salts delayed lactose crystallization. The effect on lactose crystallization was highest with calcium chloride (CaCl₂) and lowest with potassium chloride (KCl). It seems that different salts interacted with lactose to different extents. For water sorption, GAB model gave a better fit than BET model. Water sorption and time-dependent crystallization properties of lactose/salt mixtures should be considered in manufacturing and storage of dairy-based dehydrated materials.     

Effects of Chloride Salts on Appearance, Palatability, and Storage Traits of Flaked and Formed Beef Bullock Restructured Steaks

Restructured steaks made with 0.5 or 1.0% KCl, 0.5% MgCl₂ and 0.5% CaCl₂ were more desirable and darker red in raw color than blends formulated with 0.5 or 1.0% NaCl. Visual properties of raw steaks containing 0.5 or 1.0% chloride salt were scored higher than the control (no salt added) in 14 of 16 orthogonal contrast mean comparisons. Steaks made with 1.0% CaCl₂ or MgCl₂ were rated lower than the control in flavor desirability and overall satisfaction ratings. Control, 0.5 or 1.0% NaCl or 0.5 and 1.0% KCl steaks were not different in juiciness, tenderness, flavor desirability or overall satisfaction ratings. Steaks made with chloride salts were rancid after 70 days frozen storage. Results showed steaks made with KCl were superior to steaks formulated with CaCl₂ or MgCl₂.     

Effect of chloride salts on protein extraction and interfacial protein film formation in meat batters

Six comminuted chicken breast meat mixes and six meat batters were made with isoionic NaCl (25 g kg^?1), MgCl₂, CaCl₂, KCl, LiCl (IS = 0.43) and 15 g kg^?1 NaCl (IS = 0.26). The quantity and type of proteins extracted and used for interfacial protein film (IPF) formation was determined and related to batter stability. The monovalent salts produced IPF which differed in individual protein content between salts but which all contained significantly larger amounts of protein (P < 0.01) than those using divalent salts. MgCl₂ extracted more protein than CaCl₂ and produced a different protein profile in the IPF. However, MgCl₂ formed unstable raw batters whereas CaCl₂ did not. In addition, a simple, rapid method for extracting and quantifying proteins from meat batters was developed to assist in direct determination of the actual soluble protein uptake by the fat phase during comminution.     

Effect of NaCl reduction and replacement on the growth of fungi important to the spoilage of bread

The effect of NaCl and various NaCl replacers (CaCl₂, MgCl₂, KCl and MgSO₄) on the growth of Penicillium roqueforti and Aspergillus niger was evaluated at 22 °C. In addition, challenge tests were performed on white bread to determine the consequences of NaCl reduction with or without partial replacement on the growth of P. roqueforti. From the results obtained it can be concluded that at equivalent water phase concentrations the isolates exhibited differing sensitivities to the salts evaluated with NaCl and MgCl₂ having the greatest inhibitory action on the growth of A. niger and P. roqueforti, respectively. MgSO₄ had the least antifungal activity. At equivalent molalities, CaCl₂ had in general the largest antifungal activity. Although the water activity (a_w) lowering effects of the compounds studied play a large role in explaining the trends observed, at equivalent water phase concentrations MgCl₂ was found to have a smaller inhibitory effect on A. niger than that expected from its a_w depressing effect. The challenge tests revealed that no difference occurred in the growth of P. roqueforti on standard white bread, bread with 30% less NaCl and bread in which 30% of the NaCl has been partially replaced by a mixture of KCl and Sub4Salt. These results are of importance in assessing the possible microbiological consequences of NaCl reduction or replacement in bread and similar bakery products.     

Effect of sodium,potassium, calcium and magnesium chloride salts on porcine muscle proteases

This study is focused on the effect of sodium chloride alternative salts (KCl, MgCl₂ and CaCl₂) on porcine muscle proteases (cathepsins, dipeptidylpeptidases and aminopeptidases). In general, KCl exerted a very similar effect to NaCl for all the studied enzymes, while the effect of divalent salts (CaCl₂ and MgCl₂) was more pronounced. Cathepsins, dipeptidyl peptidase III, dipeptidyl peptidase IV and alanyl aminopeptidase activities were strongly inhibited by all the chloride salts especially by divalent ones. Dipeptidyl peptidase II and leucyl aminopeptidase were little affected and methionyl aminopeptidase was only inhibited by divalent salts. Dipeptidyl peptidase I was strongly activated by low concentrations of the chloride salts except NaCl. Arginyl aminopeptidase was activated by NaCl and KCl and low amounts of MgCl₂, while CaCl₂ showed a strong inhibitory effect. This is very important as these enzymes play important roles in dry-cured meats and their activity is, in general, regulated by sodium chloride. Thus, reductions in the sodium concentration with subsequent increases of other alternative cations may have relevant consequences on enzyme activity that should be taken into account when processing dry-cured meats.     

Effect of pH and NaCl/CaCl2 on the solubility and emulsifying properties of sweet potato protein

BACKGROUND: The effects of NaCl and CaCl₂ on the solubility and emulsifying properties, namely emulsifying activity index (EAI) and emulsion stability index (ESI) of sweet potato proteins (SPPs) at pH 1–10, were investigated. RESULTS: At lower NaCl (0.1 mol L^?1) and CaCl₂ (0.05 mol L^?1) concentrations, the solubility profiles of the SPPs were very similar to those in distilled water, and the lowest solubility occurred at pH 4. Increased NaCl and CaCl₂ concentration resulted in lower SPP solubility in most of the pH studied (P < 0.05). At pH < 3, NaCl improved the EAI of SPP while at pH > 7 it reduced the EAI of the SPP (P < 0.05). Moreover, addition of NaCl also resulted in reduction of ESI of the SPP in most of the pH studied (P < 0.05). On the other hand, the presence of 0.2 mol L^?1 CaCl₂ rendered the EAI and ESI of the SPPs independent of the influence of pH. CONCLUSION: The present studies show that pH and salts modified the emulsifying properties of the SPPs, and CaCl₂ at a certain concentration could be used to improve the emulsifying properties of the protein. Copyright © 2008 Society of Chemical Industry     

The effect of brine composition and pH on the yield and nature of water-soluble proteins extractable from brined muscle of cod (Gadus morhua)

Fillets of Atlantic cod (Gadus morhua) were held for 36 h in brines of pH 6.5 and 8.5, respectively, containing various combinations of NaCl, KCl, MgCl₂ and CaCl₂. Proximate analyses and chloride content were determined. Soluble muscle protein extracted in distilled water and protein released into the brine following salting was determined by SDS–PAGE. The soluble fraction was not affected by the presence of divalent salts or KCl in the brines, but it was affected by the initial pH. Both actin and myosin heavy chain (MHC) were released in pH 6.5 brines after immersion of the fish. On the other hand, an initial pH of 8.5 did not favour the release of these proteins. There was a smaller variety of remaining soluble proteins in salted muscle with an initial pH of 6.5, than with 8.5. However, this effect of the lower pH was offset to the extent that the ionic strength of the brine was higher.     

Calcium Chloride and Potassium Sorbate Reduce Sodium Chloride used during Natural Cucumber Fermentation and Storage

Cucumber fermentation characteristics and pickle quality were evaluated in brines containing equilibrium concentrations of 0-0.4% CaCl₂, 0-0.4% potassium sorbate and 0-10% NaCl. Changes in brine pH and acidity, cucumber texture and color, coliforms, lactic acid and total bacteria, yeasts and molds were followed over time. Results indicated that cucumber spoilage would eventually take place if NaCl or potassium sorbate were not present in the brine. The presence of CaCl₂ helped maintain cucumber firmness. A synergistic action between NaCl, CaCl₂ and potassium sorbate was seen, which allowed good quality pickles to be produced when moderate amounts of all three components were present in the brine (5% NaCl, 0.2% CaCl₂, 0.2% potassium sorbate).     

Glass transition and crystallization behaviour of freeze-dried lactose-salt mixtures

Glass transition temperatures were determined for dehydrated lactose/salt mixtures with various water contents and water activities, and state diagrams were established. Crystallization behaviour was studied for pure amorphous lactose stored at various relative water vapour pressures (RVP). Furthermore, glass transitions temperatures and time-dependent lactose crystallization of freeze-dried lactose and lactose/CaCl₂, lactose/NaCl, lactose/MgCl₂ and lactose/KCl mixtures in molar ratios of 9:1 were determined. Glass transition temperatures (T_g) of lactose powder as determined by differential scanning calorimetry (DSC) was lower than that of lactose/CaCl₂ (9:1)_, and lactose/MgCl₂ (9:1), but it was slightly higher than the T_g of lactose/NaCl (9:1), and lactose/KCl (9:1). Lactose/KCl had the lowest glass transition temperature, but it had about the same crystallization temperature as lactose/NaCl, and lactose/MgCl₂. The glass transition temperatures decreased as water contents increased. The critical water contents and water activities at 23 °C were predicted using data on glass transition temperature and water sorption. Pure lactose had a different critical water activity and water content from lactose/salt mixtures. The critical values of lactose/CaCl₂ (9:1) were the highest. Loss of sorbed water, indicating lactose crystallization, was observed in lactose and lactose/salt mixtures stored above the critical RVP.     

Isolation of Actomyosin and Myosin from Post-Rigor Turkey Breast and Thigh

Myosin/actomyosin (MAM) was extracted from post-rigor turkey breast and thigh muscles using Hasselbach-Schneider solution. Electrophoretic evaluation of the breast muscle protein extract showed it to be 86.4% myosin and 7% actin. Thigh muscle MAM contained 79.4% myosin and 4.7% actin. Slight variations in minor protein bands were observed between the breast and thigh MAM electrophoretic profiles. Gel filtration of MAM on a 2% agarose column separated actomyosin from myosin. Myosin purity was 97.9% and 99.2% for breast and thigh, respectively. Gel filtration data indicated that myosin, unassociated with actin, was the predominate protein extracted from the post-rigor tissue. Myosin was approximately 67-72% of the original MAM.     

Purification and characterization of lysozyme from filipino venus, Ruditapes philippinarum

Lysozyme from Filipino venus (Ruditapes philippinarum) was purified by ion-exchange and gel filtration chromatography. The purification fold and yield were 3,402 and 32.4%, respectively. The molecular weight was determined to be 13.4 kDa by SDS-PAGE. The specific activity of lysozyme was 3.76×10⁵ units/mg protein with Micrococcus lysodeikticus as a substrate. The optimum temperature and pH of lysozyme were 75°C and 5.5, respectively. Lysozyme activity was decreased with about 45% after heat treatment for 30 min at 80°C, and completely inactivated at 100°C. It was activated by NaCl (10–70 mM), MgCl₂, and CaCl₂ (2–5 mM) whereas it was inhibited by ZnCl₂ (2–30 mM).     

Effects of pH and Salts on Physical and Mechanical Properties of Pea Starch Films

To identify the significant contribution of intermolecular hydrogen bonds of starch molecules to the film structure formation, pH of film‐forming solutions was adjusted and also various salts (NaCl, CaCl₂, CaSO₄, and K₂SO₄) were mixed into the glycerol‐plasticized pea starch film. The film made from pH 7 possessed the highest tensile strength‐at‐break (2 times) and elastic modulus (4 to 15 times) and the lowest elongation‐at‐break compared with those of the films made from acid and alkali environments. The pH 7 film also has the highest film density and the lowest total soluble matter. At the level of 0.01 to 0.1 M of CaSO₄ and 0.1 M of K₂SO₄ in a kilogram of starch, the water solubility of the film increased, while chloride salts slightly lowered the solubility. NaCl and CaSO₄ reduced water vapor permeability (WVP), while CaCl₂ slightly increased WVP at 0.01 and 0.06 M concentrations, and K₂SO₄ significantly increased WVP at 0.03 and 0.15 M. Presence of salts increased tensile strength (5 to 14 times than the control films) and elastic modulus (35 to 180 times) of starch film at 0.01 to 0.03 M of CaSO₄ and K₂SO₄. Elongation‐at‐break increased significantly as salt concentration increases to an optimal level. However, when the concentration exceeded above the optimal level, the E of starch films decreased and showed no significant difference from the control film. Overall, the addition of salts modified physical and mechanical properties of pea starch films more than pH adjustment without any salt addition.     

Effect of Sodium Chloride and Phosphates on the Thermal Properties of Chicken Meat Proteins

Maximum thermal transition (T_max) and denaturation enthalpy (ΔH) of water-washed myofibrils and finely cut chicken breast muscle, treated with 1–4% NaCl and/or 0.25–1% of either pyrophosphate (PP) or tripolyphosphate (TPP), were monitored by differential scanning calorimetry. Increasing the concentration of NaCl destabilized the heat resistance of the proteins in water-washed myofibrils and in meat specimens. Actin showed the greatest reduction of T_max, a 16°C decline in the presence of 4% NaCl. In a meat system, the addition of 4% NaCl resulted in one T_max instead of five transitions, as seen in untreated meat. The presence of PP and TPP, especially in concentrations of 0.25 and 0.50%, enhanced the thermal stability of myosin. Changes in denaturation temperatures of proteins were accompanied by corresponding changes in AH.