Antioxidative Activity of Maillard Reaction Products in Cooked Ground Beef, Sensory and TBA Values

Maillard reaction products (MRPs) obtained by autoclaving egg albumin acid hydrolysate and glucose for 1 hr were added to ground beef which was cooked and stored at 4°C for 8 days. The antioxidative activity of MRPs was investigated by a trained sensory panel and the TBA test. The panel evaluated samples for loss of desirable cooked beef notes and generation of off-flavors, such as cardboard and painty. With added 1% MRPs, painty aroma and flavor scores were low and did not (p > 0.05) change over time. The coefficients of determination were high (r²= 0.92 to 0.77, p < 0.0001) between aroma and flavor scores for any two similar attributes. The TBA values decreased by 17% with the addition of 0.5% MRP and by 39% with 1% MRP over time.     

Interaction of Reduced NaCl, Sodium Acid Pyrophosphate and pH on the Antimicrobial Activity of Comminuted Meat Products

Meat (beef-pork) batters were formulated with NaCl (2.3% and 4.1% brine) and with 0.5% sodium acid pyrophosphate (SAPP) in combination with 2.3% brine. The adjusted pH of raw batters resulted in cooked meat pH values of 5.7, 6.0, and 6.3. Inoculated (Clostridium sporogenes spores) and uninoculated batters in cans were cooked to 70°C and stored for abuse at 27°C. Microbial growth was delayed and the short shelf-life of low brine (2.3%) products was extended with SAPP in the formulation. The antimicrobial properties of treatments with SAPP were due to both declining pH and presence of phosphate in the formulation. Potential mechanisms of microbial inhibition by SAPP are discussed.     

Yields, Color and Compositions of Washed, Kneaded and Heated Mechanically Deboned Poultry Meat

Kamaboko-like products, prepared with NaCl and phosphate buffer wash solutions, had higher yields compared to those prepared with Na-acetate and polyphosphate solutions. Products prepared with polyphosphate wash solution were lightest in color. Higher fat in mechanically deboned poultry meat caused lower yields than lower fat. There were no interactions (P>0.05) between the temperatures and salt concentrations of the wash solutions on yields of products washed with various concentrations of NaCl. Products prepared with NaCl wash solutions at 2–4^oC had higher yields than those prepared at 20–22^oC. Generally, products prepared with 1.0% or 1.5% NaCl wash solutions had higher Hunter “L” values and lower Hunter “a” values when compared to those prepared with 0 or 0.5% NaCl washing solutions.     

Evaluation of the effect of Ultra Rice® EDTA supplementation on the soluble iron,visual acceptance and vitamin A stability of commercial milled rice blends

The addition of NaFeEDTA at only 5% of total iron to ferric pyrophosphate‐fortified Ultra Rice^® increased the in vitro soluble iron ten‐fold. Ultra Rice^® formulated with NaFeEDTA at 2–7% of total iron, or with Na₂EDTA·2H₂O at 0.5× the total iron equivalents, increased the soluble iron seven‐ to thirty‐fold. The colour of the batches was acceptable through 20 weeks at 21 °C, but colour stability needs to be evaluated under authentic storage conditions. Although only 34–46% of the initial vitamin A remained after extrusion, 18‐week storage at 30 °C/70% relative humidity, and simulated cooking, there were indications that losses could be decreased by raising the pH (to ~5) and/or using a better protected vitamin A ingredient. The enhancement of soluble iron afforded by low‐level NaFeEDTA or Na₂EDTA·2H₂O supplementation suggests that this fortification strategy may merit further study as a means of increasing absorbable iron in Ultra Rice^®.     

Effects of Fat and NaCl/Phosphate Levels on the Chemical and Sensory Properties of Pork Patties

Ground pork shoulders were combined with 50/50 pork trimmings to achieve fat levels of 20.0, 23.3, 26.6, and 30.0%. Salt/phosphate (NaCl/PO₄) combinations of 0/0, 1/0, 1/0.25 and 2%/0.5% were blended with each fat level. Each treatment combination was stored at 3°C for 7 days in air-permeable film (AP), 21 days in vacuum pouches (VP) and at ?23°C for 90 days in double-wrapped (DW) freezer paper. Fat level did not affect pH, expressed moisture (EM), peroxide value (PV), 2-thiobarbituric acid (TBA) values or cooking losses. Patties with 30.0% fat were jucier and required less energy to compress. A combination of 1%NaCl/0.25%PC₄ reduced cooking losses, enhanced sensory properties and moderated the oxidation effects of NaCl up to 60 days of frozen storage. The NaCl treatment accelerated lipid oxidation most during all storage conditions while the control remained the least oxidized.     

Use of Response Surface Methodology to Study the Combined Effect of Salt, pH, and Temperature on the Growth of Food-Spoiling Halotolerant Yeast, Debaryomyces nepalensis NCYC 3413

This paper reports the interaction of salt (NaCl and KCl), initial pH, and temperature and their effects on the specific growth rate and lag phase of food spoiling halotolerant yeast, Debaryomyces nepalensis. The optimization of salt, initial pH, and temperature was carried out using response surface methodology based on central composite design. The mathematical model showed that salt has a significant effect on specific growth rate and lag phase of D. nepalensis. The optimal conditions of salt concentration, pH, and temperature of growth were found to be 0.3 M NaCl, 7.1, 26 °C and 0.6 M KCl, 5.6, 25°C, respectively. Under these conditions, a maximum specific growth rate of 0.41 and 0.5 h⁻¹ was observed in medium containing NaCl and KCl, respectively. Lag phase can be increased most effectively either by increasing salt concentrations or both by decreasing (≤20°C) or increasing the temperature (≥40°C) with moderate (1.5 M) or low salt concentration (0.5 M), respectively. Results show that D. nepalensis need to generate weak acids to maintain the intracellular pH under pH and saline stress conditions. The results obtained in this study will be helpful in using optimal conditions for the maximum growth of the strain for the production of certain metabolites like organic acids and glycerol and designing food preservation procedures.     

Synergistic effect of Sodium Chloride,temperature and pH on growth of a cocktail of spoilage yeasts: a research note

The effect of sodium chloride (0·5–10% w/v), pH (2·6–6·3) and temperature (1–22°C) were studied on the growth of a cocktail of food spoilage yeasts. The length of the lag phase and the time taken to reach the level of 10⁶cfu ml⁻¹were calculated for each set of conditions. It was found that the lag phase constituted as little as 21% of the total time to reach 10⁶cfu ml⁻¹when the yeasts were grown in favourable conditions and as much as 62% of the total time when more extreme conditions were used. It was concluded that the lag phase was the most important factor affecting the spoilage potential of chilled foods with low pH and high salt values. The single most effective factor in reducing the growth rate of yeasts was temperature. The lag phase was 15, 38, 270, 630 and 875 h when the temperature was 15, 8, 4, 2 and 1°C respectively. At any single temperature, there appeared to be a synergistic effect of NaCl and pH and under the most extreme conditions tested (1°C; pH 5·8; 6% NaCl), the lag phase was over 1000 h. These data have implications for the spoilage potential of high salt, reduced pH foods stored at chill temperatures.     

Functional, Sensory, and Microbiological Properties of Restructured Beef and Emu Steaks

Beef and emu steaks were restructured with 5% fibrinogen/0.25% thrombin (F), 0.5% algin/0.5% calcium lactate (A), or 0.5% phosphate/1.5% salt (P). P and A treatments had higher cooked binding strengths and cook yields than the F treatments (P < 0.05). The pH and cook yields of restructured emu were higher than beef (P < 0.05). Binding strength of emu was lower than beef in all binding systems (P < 0.05). F solution had an aerobic plate count (APC) of 39,000/g and increased the microbial count in restructured emu steaks from 940 to 7500/g (P < 0.05). Cooking to 60°C reduced APC to < 250/g (P < 0.05) with progressively greater bacterial kill after cooking to 66°C or 75°C.     

Viscoelastic properties of caseinmacropeptide isolated from cow,ewe and goat cheese whey

Caseinmacropeptide (CMP) is a C‐terminal glycopeptide released from κ‐casein by the action of chymosin during cheese‐making. It is recognised as a bioactive peptide and is thought to be an ingredient with a potential use in functional foods. CMP occurs in sweet cheese whey and whey protein concentrate (WPC). Its composition is variable and depends on the particular whey source and the fractionation technology employed in the isolation. There were no significant (P < 0.05) differences in the relative apparent viscosities between species of CMPs (cow, ewe and goat). Analyses at different pH (2, 4, 7, 10), ionic strength (0, 0.2, 0.4 and 0.7 as NaCl molarity) and protein concentration (50, 100 and 200 g kg^?1) at temperatures from 10 to 90 °C carried out found pH 7 and high protein concentration (200 g kg^?1) conditions to be the best for CMP solutions to keep low and constant relative viscosity values with increasing temperature up to 75 °C. The viscoelastic properties–storage modulus, loss modulus and phase angle–of the different CMPs and WPC solutions were determined. Heat‐induced rheological changes in CMP solutions occurred at moderate temperatures (40–50 °C) with no appreciable differences in viscosity. Gelation took place significantly (P < 0.05) earlier in goat CMP (41 °C), followed by cow CMP (44 °C), ewe CMP (47 °C) and WPC (56 °C). Heating at 90 °C showed that WPC required significantly (P < 0.05) longer times to form gels (>5 min) than the CMPs (<5 min). WPC gels had higher (>20°) phase angle than CMP (<20°), which could be associated with untidy structures, limiting elastic properties of the gel. Copyright © 2006 Society of Chemical Industry     

Increasing nutrient availability of feather meal for ruminants and non‐ruminants using an ammonia pressurisation/depressurisation process

An ammonia pressurisation/depressurisation process (PDA) was evaluated for efficacy in enhancing solubility and digestibility of feather meal (FM) protein. Commercial FM was processed for 5 min with variable ammonia loadings (0.5–2 g g⁻¹ DM), moisture contents (10–50%) and temperatures (75–90 °C). Dry matter and protein solubility were determined in a 0.15 M NaCl solution (6 h, 39 °C) and soluble protein content was determined by the Lowry method. Ruminal solubility was determined by the Kjeldahl method as protein lost in the rumen (1 min) of a cannulated steer. Protein digestibility (crude protein by Kjeldahl analysis) was determined using the in situ dacron bag and pepsin techniques. Protein solubility in the untreated FM was low (13.3 and 7.2%, in NaCl and in rumen fluid, respectively) and increased (p < 0.05) to 39.4 and 23.0%, respectively, in the treated FM at the optimal conditions (50% moisture, 2 g ammonia g⁻¹ dry FM and 90 °C). Ruminal and pepsin protein digestibilities increased (p < 0.05) with increasing moisture content, ammonia loading and temperature. Protein digested in the rumen at 12 h increased from 21.9 (untreated) to 43.0%. Highest digestibility value at 48 h was 54.8%. Pepsin protein digestibility increased (p < 0.05) from 35.4% in the untreated FM to 89.3% in the optimal treatment. Protein solubility in NaCl correlated very well (0.98) with pepsin digestibility. The 3‐fold increase in solubility and 2‐fold increase in digestibility could improve nutrient availability of FM and increase its value as a protein source for both ruminants and non‐ruminants. © 1999 Society of Chemical Industry     

Influence of pH,NaCl and pre‐incubation on utilisation of surimi wash water in generation of antioxidative material by using the Maillard reaction

Maillard reaction products (MRPs) were generated from reaction mixtures of surimi wash water (SWW) with glucose or fructose (5%w/v) heated at 95 °C for 2–12 h. The effects of pH, NaCl and pre‐incubation of SWW on the Maillard reaction and antioxidant capacity of MRPs were investigated. The antioxidative capacity of MRPs was determined by measuring free DPPH° radical scavenging activity and reducing power. The highest colour intensity (OD₄₂₀) as well as antioxidative capacity was noted in the reaction mixture containing fructose at pH 9.0. The addition of NaCl (0.5–2.5%w/v) caused reduction in browning intensity but enhanced antioxidative capacity of the MRPs. Pre‐incubation of SWW at 45 °C for 4 h decreased soluble protein but increased the Maillard reaction and antioxidative capacity of MRPs. A positive effect of salt or pre‐incubation of SWW on the antioxidative capacity of MRPs was not associated with the soluble protein content in the reaction mixture.     

Identification by GeLC‐MS/MS of Trypsin Inhibitor in Sarcoplasmic Proteins of Three Tropical Fish and Characterization of Their Inhibitory Properties

Sarcoplasmic proteins from 3 fish species were fractionated by 50% to 70% ammonium sulfate precipitation. Lyophilized fractionated sarcoplasmic proteins of threadfin bream (TB‐SP), bigeye snapper (BS‐SP), and yellow croaker (YC‐SP) showed 80% to 92% trypsin inhibitory activity. Trypsin inhibitory activity staining gel electrophoresis revealed bands at 32, 33, 37, 45, 48, and 50 kDa for the 3 species, and a band at 95 kDa was observed for TB‐SP and YC‐SP. Alpha‐1‐antitrypsin with molecular mass of 45 to 50 kDa was identified in YC‐SP by gel‐based liquid chromatography‐tandem mass spectrometry (GeLC‐MS/MS). Other major protein bands appeared on trypsin activity staining included phosphorylase, glyceraldehyde‐3‐phosphate dehydrogenase, and creatine kinase with molecular mass of 95 and 35 to 40 kDa, respectively. But, these 3 proteins did not show true trypsin inhibitory activity. Trypsin inhibitory activity of fractionated sarcoplasmic proteins showed good stability, with >80% activity retained at 60 °C and up to 0.6 M NaCl. TB‐SP showed the highest inhibitory activity against autolysis of washed threadfin bream mince at 65 °C. Addition of 0.5% or 1% TB‐SP improved textural properties of threadfin bream surimi gels preincubated at 37 or 65 °C followed by heating at 90 °C. Therefore, TB‐SP could be a promising protein ingredient for enhancing surimi gel texture.     

Characteristics and Functionality Enhancement by Glycosylation of Bitter Melon (Momordica charantia) Seed Protein

Seeds of ripe bitter melon (Momordica charantia) contain approximately 30% protein. However, this protein, which is less functional than soy protein, may have desirable functionalities as a food ingredient after modification. Bitter melon seed protein isolate (BMSPI) was prepared under optimal extraction conditions (defatted meal to 1.3 M NaCl was 1:10 w/v; pH 9.0) and its functional properties were investigated before and after modification by glycosylation. Glycosylation was conducted at varying relative humidities (50%/65%/80%) and temperatures (40 °C/50 °C/60 °C) using a response surface central composite design. Degree of glycosylation (DG) ranged from 39.3 to 52.5%, 61.7 to 70.9%, and 81.2 to 94.8% at 40 °C, 50 °C, and 60 °C, respectively (P values < 0.0001). Denaturation temperatures of all DGs ranged from 111.6 °C to 114.6 °C, while unmodified/native BMSPI had a value of 113.2 °C. Surface hydrophobicity decreased to approximately 60% when the DG was maximal (94.8%). Solubility decreased almost 90% when the DG was maximal in comparison to the native BMSPI (62.0%). Emulsifying activity increased from 0.35 to 0.80 when the DGs were ≥80%, while emulsion stability increased from 63 to 72 min when the DGs were greater than 70%. A similar trend was observed with foaming capacity and foaming stability of the glycosylated proteins. This glycosylated BMSPI with improved emulsifying and foaming properties could be used as an ingredient in food products where such properties are required.     

Microbiological, Chemical, and Physical Changes in Fresh, Vacuum-Packaged Pork Treated with Organic Acids and Salts

The effects of selected organic acids and salts on microbial numbers, pH, exudate, and color were studied for vacuum-packaged, fresh pork chops. Pork chops were dipped for 2 min in (v/v) 1% acetic acid, 1% acetic/1% lactic acid, 1.5% acetic/1.5% sodium acetate, 3% acetic/3% sodium ascorbate, 3% acetic/2% NaCl or sterile, distilled water before being vacuum-packaged and stored at 2°– 4°C for 6 weeks. Treatments containing 3% acetic acid resulted in lower aerobic microbial numbers (P < 0.05) and effectively inhibited Enterobacteriaceae. Treatments containing 1% acetic acid, with or without 1% lactic acid, were ineffective. All acid treatments increased exudate and were detrimental to meat color (P < 0.05) although sodium ascorbate reduced color damage. Chops treated with 3% acetic acid/3% sodium ascorbate had the highest Hunter a and L color scores.     

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).     

Gamma-Irradiation of CIostridium botulinum Inoculated Turkey Frankfurters Formulated with Different Chloride Salts and Polyphosphates

The effects of gamma-irradiation doses (0, 0.5, and 1.0 Mrad) on C. botulinum toxin production in turkey frankfurters formulated with three different chloride salts (NaCl, KCl, and MgCl₂) at isoionic strength (equal to 2.5% NaCl) and three types of phosphates added to 2.0% NaCl frankfurters were studied. The use of 2.5% NaCl together with 0.5 or 1.0 Mrad was substantially more effective at inhibitinlg botulinal toxin production when frankfurters were incubated at 27°C than the combination of irradiation with KCl or MgC1₂ (40, 9, and 4 days, respectively, when treated with 1 Mrad). Phosphate addition revealed that 0.4% sodium acid pyrophosphate addition was the most inhibitory for botulinal toxin production followed by hexametaphosphate and tripolyphosphate addition.     

Sodium Chloride Diffusion in Low‐Acid Foods during Thermal Processing and Storage

This study aimed at modeling sodium chloride (NaCl) diffusion in foods during thermal processing using analytical and numerical solutions and at investigating the changes in NaCl concentrations during storage after processing. Potato, radish, and salmon samples in 1% or 3% NaCl solutions were heated at 90, 105, or 121 °C for 5 to 240 min to simulate pasteurization and sterilization. Selected samples were stored at 4 or 22 °C for up to 28 d. Radish had the largest equilibrium NaCl concentrations and equilibrium distribution coefficients, but smallest effective diffusion coefficients, indicating that a greater amount of NaCl diffused into the radish at a slower rate. Effective diffusion coefficients determined using the analytical solution ranged from 0.2 × 10^–8 to 2.6 × 10^?8 m²/s. Numerical and analytical solutions showed good agreement with experimental data, with average coefficients of determination for samples in 1% NaCl at 121 °C of 0.98 and 0.95, respectively. During storage, food samples equilibrated to a similar NaCl concentration regardless of the thermal processing severity. The results suggest that sensory evaluation of multiphase (solid and liquid) products should occur at least 14 d after processing to allow enough time for the salt to equilibrate within the product.     

Inactivation and injury of Listeria monocytogenes as affected by heating and freezing

The effects of heating and freezing Listeria monocytogenes in tryptose phosphate broth an inactivation and injury were investigate. Four strains (Scott A, Brie-1, LCDC 81–861, and DA-3) were examined. Only slight decreases in the viable populations pf all four strains were detected after 75 min at 50°C. Populations of strains Scott A, LCDC 81–861, and DA-3 were reduced to non-detectable levels after 10 min at 60°C while viable cells of strain Brie-1 were recovered after heating at 60°C for 30 min. Viable populations of all four strains declined steadily at 52,54, and 56°C; similar inactivation rates were observed for strains Scott A, LcDC 81–861, and DA-3. Strain Brie-1 was consistently the most heat resistant. Substantial populations of viable cells of all strains heated at 52, 54, and 56°C were injured as evidenced by increased sensitivity to NaCl when plated on tryptose phosphate recover agar. Strain DA-3 was the most susceptible strain to sublethal heat injury. Viable populations of all four test strains were not appreciably reduced after 14 days at −18°C, although strain LCDC 81–861 lost viability at a more rapid rate at this temperature than did the other test strains. About 72, 82, 73, and 80% of Scott A, Brie-1, LCDC 81–861, and DA-3 cells, respectively, held at −18°C for 14 days were not receovered on tryptose phosphate agar (TPA) supplemented with 8% NaCl compared to populations recovered on TPA not supplemented with NaCl.     

Determination of Oxygen Solubility in Liquid Foods Using a Dissolved Oxygen Electrode

A rapid method for determining oxygen solubility in foods was introduced. Fructose, glucose, sucrose, orange juice, apple juice, grape juice, grapefruit juice, lemonade, and tomato juice had similar oxygen solubilities at comparable °Brix readings. The equation: In [ppm O₂] = 2.63 ? 0.0179 (°Brix) ? 0.0190 (°C) estimated to within 5% the oxygen solubility of sugar solutions and fruit juices at temperatures between 4°C and 40°C. At likely food concentrations, citric acid, ascorbic acid, and NaCl reduced oxygen solubility by less than 10%. Tests for component interactions were also conducted. There was no measurable synergism or antagonism between fructose, glucose, and sucrose with or without organic acids.     

Effect of marinating ingredients on temperature-induced denaturation of hemoglobin and its relation to red blood spot formation in cooked chicken breast

Red blood spot (RBS) commonly found in cooked chicken breast has caused severe economic loss as it is perceived as a sign of undercooked product. The objectives of this study were to investigate the cause of RBS as related to common ingredients used in marination, based on both chicken breast and isolated chicken hemoglobin (Hb) models. The effect of sodium chloride (NaCl), sodium tripolyphosphate (STPP), and glucose on thermal denaturation of Hb was investigated along with the extent of RBS formation in cooked marinated chicken breast. After vacuum tumbling for 65 min and subsequent storage at 4 °C for 20 hr, STPP and glucose were not absorbed into the center of chicken breast. However, Na⁺ was absorbed after 12 hr storage. The denaturation temperature (T_d) of isolated chicken Hb decreased to 65.8 °C in the presence of 1.5 M NaCl, while that of the control was 69.4 °C. STPP at pH 9 decreased T_d of Hb to 61.4 °C. The alkaline pH induced by STPP destabilized the Hb structure. RBSs were observed at 100% incidence when cooked to core temperatures of 50 and 70 °C for 1 min. RBSs were completely eliminated at core temperature of 85 °C. The ingredients used during marination appeared to have a minimal effect on RBS formation due to their limited absorption into the chicken breast. The cooking temperature is a major factor governing RBSs, as it directly affects the denaturation of Hb.