Forms of Iron in Meats Cured with Nitrite and Erythorbate

Solubility, valence, and complexation of iron were measured in four different processed meats cured with or without 156 ppm sodium nitrite and with or without 550 ppm sodium erythorbate (d-isoascorbate). Nitrite caused less ionic iron and erythorbate caused more ferrous and soluble iron after a conventional curing process. Heme iron levels were unchanged. No changes were detected in vacuum packed meats after 160 days at -40 or after 14 days at 5°C. Exposure to air at 5°C depleted ferrous iron and oxidized erythorbate. Boiling for 15 min doubled complexed iron in all four meat formulations. The forms of iron in processed meat depended on the curing ingredients as well as air and heat exposure.     

Effect of cooking or handling conditions on the furan levels of processed foods

The aim of this study was to investigate the possible effects of cooking or handling conditions on the concentration of furan in processed foods. The analytical method used to analyse furan levels in foods was optimized based on solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS). In baby soups, the concentration of furan decreased by up to 22% after opening a lid for 10 min. In the baby food in retort packaging, the level of furan was reduced by 15–33% after heating the foods at 50°C without a lid. Furan in rice seasonings was evaporated completely after heating the foods at 60°C. Regarding powered milk, the levels of furan were too low to be compared under various conditions. The levels of furan decreased to 58% in beverage products for babies, after storing them at 4°C for 1 day without a lid. The levels of furan in canned foods such as cereal and vegetable were reduced by zero to 52% when they were stored without stirring in a refrigerator at 4°C for 1 day. When we boiled canned fish, the furan present was almost completely evaporated. It is recommended that canned meats be heated up to 50–70°C for the reduction (26–46%) of furan levels. The levels of furan in instant and brewed coffee samples were significantly reduced after storing for 11 to 20 min at room temperature without a lid (p < 0.05).     

Antimicrobial and preservative activity of garlic on fresh ground camel meat. I. Effect of fresh ground garlic segments

A method to prolong the shelf-life of fresh camel meat, by the use of fresh garlic as an antimicrobial and preservative agent, has been established. Three storage temperatures (room temperature 20–22°C, incubator 12°C and refrigerator 2–3°C) were used in this investigation. Irrespective of storage temperature, treatments with 5, 10 and 15% (by wt.) of fresh garlic segments, ground with fresh lean camel meat, were found to increase the period of shelf-life, two-, three- and more than four-fold, respectively, compared with the corresponding control samples. After 4 days storage at room temperature, 12 days incubation and 28 days refrigeration, it was found that treatments with 15 and 25% garlic resulted i* complete inhibition of microbial growth with no sign of any organoleptic spoilage of the meat. The treated meat samples were fried for 15 min and found to be acceptable in taste and flavour by the local people in Saudi Arabia.     

Parameters affecting the isolation of collagen from squid (Illex argentinus) skins

The solubility of collagen from squid (Illex argentinus) skin in salt solutions and the efficiency of removal of skin chromatophores were determined. Homogenization of minced squid skin in 5–15% NaCl solution at 0°C solubilized 35–24% of total amount of crude protein and caused 2–5% loss of collagen but was not effective in removing pigments from the skin. The treatment of whole squid skins in 5–15% NaCl solutions at room temperature led to separation of the chromatophores, but the loss of soluble collagen was 57–16%. Collagen, soluble in dilute acid solutions was isolated from squid skins by 24 h soaking in 10% NaCl solution at room temperature, washing with water and bleaching for 48 h in 1% H₂O₂ in 0.01 M NaOH. The yield of collagen was 53%. It could be increased to 90% by using NaOH solution at pH 11.5 instead of 10% NaCl but the isolate was less soluble in dilute acid and the viscosity of 0.5% dispersion of collagen was four times lower. The rancid off-odour could be prevented by adding 0.5% of a non-ionic detergent to all solution used in the procedure. ©     

High pressure-induced tapioca starch gels: physico-chemical characterization and stability

Gelatinization of tapioca starch (25% dry basis) was induced by high hydrostatic pressure processing (HPP) at 600 MPa under different time and temperature regimes (30 °C for 10, 20 and 30 min; 50 °C for 10 min; 80 °C for 10 min). Textural, thermal and structural properties of the gels were studied and their stability was evaluated after 28 days of refrigerated (4 °C) and frozen (−18 °C) storage. Thermally induced gels (90 ± 1 °C, 20 min, gel-T) were used as controls. HPP resulted in the formation of harder gels than thermal processing (more significantly at lower processing temperatures) partially preserving the granular structure of the native starch. Longer HPP treatments caused only a slight decrease in hardness that was significant only at longer processing times (30 min). DSC thermograms of high pressure-induced samples showed a more asymmetrical ice-melting peak than that of thermally induced gels. Asymmetry of the peak of HP treated samples was more pronounced in samples processed at lower than at higher temperature. A different starch–water and/or starch/starch interaction may be hypothesized. During storage, all samples became stiffer and the amylopectin recrystallization increased, more extensively in thermally induced than in HPP samples where a stronger starch–starch and/or starch/water interactions may have hindered the recrystallization process.     

Nutritional, Microbiological, and Sensory Qualities of a Peanut Beverage Prepared Using Various Processes

Nutritional, microbiological and sensory qualities of peanut beverages processed at 85°C, 100°C and 121°C for 15 min and 121°C for 3 sec were determined. Heating improved the digestibility of peanut beverages, particularly those processed at 121°C for 3 sec and 85°C for 15 min. Methionine was particularly sensitive to the treatment at 121°C. The limiting amino acids were threonine, cystine, valine, lysine and tyrosine. No microbial growth was observed in products processed at 100°C and 121°C followed by storage at 4°C and 30°C for 20 days. Beverage processed at 85°C and stored at 30°C for 3 days contained an aerobic microbial population of 2.4 × 10⁴ CFU/mL. The beany flavor was least pronounced in beverages processed at 100°C for 15 min and strongest at 121°C for 3 sec.     

Assessment of Previous Heat Treatment of Laboratory Heat-Processed Meat and Poultry using a Commercial Enzyme System

The APIZYM enzyme system was assessed with respect to: enzyme activity in aqueous and saline extract filtrates from raw and heat processed (60° and 71.1°C) beef; effect of rate of heating (0.2–0.3°C, 0.4–0.5°C, and 0.9–1.0°C/min) to internal temperatures of 66.7°, 67.8°, 68.9°, 70.0°, and 71.1°C and holding times of 0, 15, 30, 45, and 60 min at these temperatures on residual enzyme activity; reduction of enzyme assay incubation time; and reproducibility of the system. Results showed that slightly higher enzyme activity in heated samples was obtained with 0.9% saline extraction compared to water. Greater enzyme activity was observed in filtrates from pork samples heat-processed at a fast rate than at a slow rate. Enzyme activity could be detected after 2 hr incubation, but 4 hr were needed for the enzymes to react with their respective substrates. The system was found to be reproducibile. The results of this study also indicated the potential of using leucine aminopeptidase as an indicator enzyme for determining the adequacy of heat treatment of meat and poultry products.     

Non-enzymatic Depolymerization of Carrot Pectin: Toward a Better Understanding of Carrot Texture During Thermal Processing

ABSTRACT Pretreated carrot discs were thermally processed (90 °C to 110 °C) in closed containers and the resulting textural characteristics were analyzed. The pretreatment conditions used include conventional high‐temperature blanching (90 °C, 4 min), low‐temperature blanching (LTB = 60 °C, 40 min), LTB combined with 0.5% calcium chloride soaking, LTB combined with 2% sodium chloride soaking, high pressure pretreatment (HP = 400 MPa, 60 °C, 15 min), HP combined with 0.5% calcium chloride soaking, and control (non‐pretreated sample). Alcohol insoluble residues (AIR) from the pretreated carrot discs were characterized in terms of degree of methoxylation (DM). The AIR samples were further subjected to fractionation into water‐soluble pectin (WSP), chelator‐soluble pectin (CSP), and sodium carbonate‐soluble pectin (NSP). Heat depolymerization patterns and β‐elimination kinetics were investigated on the different pectin fractions. Thermal texture degradation was strongly influenced by the pretreatment condition used and the processing temperature during subsequent thermal treatment. Pretreatment conditions that showed a significant reduction in DM exhibited decreased WSP content, reduced β‐elimination, and consequently superior textural characteristics. β‐elimination was markedly pronounced in the highly methoxylated WSP fractions. CSP and NSP fractions were insensitive to β‐elimination. A strong correlation (r> 0.95) between thermal texture loss of carrots and β‐elimination kinetics exists. Overall, the benefits of controlled pectinmethylesterase activity in carrot processing were pointed out.     

Effect of Heat Treatment for Trypsin Inhibitor Inactivation on Physical and Functional Properties of Peanut Protein

Trypsin inhibitor (TI) inactivation in whole peanut kernels exposed to moist heat had a decimal reduction time (D) of 91 min at 100°C and 9.3 min at 120°C. When all processing times were converted to process time at 120°C using Z of 20°C, the composite D at 120°C was 10 min. Solubility decreased with heating to reach a minimum with 98% TI inactivation. Capacities to spontaneously absorb water and to gel were retained better on heating at 120°C than at 100°C for equal TI inactivation. The most functional protein was in kernels heated at 120°C for 10 min. When 20 or 30% meat protein in a meat loaf formulation was replaced with the latter peanut protein, the resulting loaf retained more fat and water and exhibited higher shearing strengths than all meat formulations.     

Application of a polymerase chain reaction (PCR) method as a complementary tool to microscopic analysis for the detection of bones and other animal tissues in home‐made animal meals

A polymerase chain reaction (PCR) method was compared with a variation of the official microscopic technique (Directive 98/88/EC) for the detection in animal meals of cereals (wheat and corn) and animal parts (bone, feathers, meat, liver, fat and blood). Microscopy successfully detected animal bones in raw feeds with a sensitivity of 1 g kg^?1, while the sensitivity of the PCR method was in the range of 5–10 g kg^?1. Microscopy also allowed the detection of animal bones and feathers in feeds processed at 115 and 133 °C but failed to detect other animal materials. The PCR method successfully detected cereals (wheat and corn) as well as meat, bone, liver, fat and feathers after processing at 115 °C for 20 min. Heating at 133 °C under overpressure (autoclave) conditions resulted in more intense DNA fragmentation and lower DNA extractability. Nevertheless, bone and liver, as well as wheat and corn in home‐made animal meals, were successfully detected even after heating at 133 °C for 20 min. Copyright © 2004 Society of Chemical Industry     

Residual glutamic-oxaloacetic transaminase (GOT) activity in thermally processed poultry and poultry products as an indicator of end-point temperatures

Glutamic-oxaloacetic transaminase (GOT) activities in chicken and turkey thigh and breast meat samples, thermally processed at 60–84°C in a model heat-treating system, were evaluated for use as indicators of end-point cooking temperatures (EPT). Wings, breasts, thighs and legs from commercially cooked, whole, roasted chickens and commercially processed products containing chicken and turkey meat were analyzed also to determine if residual GOT activities would indicate compliance with recent FDA/FSIS EPT recommendations. Activities of samples processed in the model system decreased logarithmically with increasing temperatures. GOT activities were higher (P < 0·05) in thigh meat than breast meat in both chicken and turkey samples; activities were higher in turkey than chicken. GOT values for chicken thigh and breast meat at 74°C, the FDA/FSIS recommended EPT for use by food handlers and retailers, were 735 and 164 Sigma-Frankel units ml^?1 (SFU ml^?1), respectively. Values for turkey thigh and breast meat at this temperature were 1080 and 450 SFU ml^?1, respectively. The range of activities was 7–13 SFU ml^?1 in commercially prepared chicken products and 27–161 SFU ml^?1 in turkey products. Analysis of these products showed adequate cooking and compliance with FDA/FSIS recommended EPT for retail sale. These data indicate that residual GOT activity in processed poultry has potential for use as an indicator of EPT.     

Assessment of Methodologies for Calorimetric Cholesterol Assay of Meats

The objective of this study was to assess the critical factors influencing the values for meat cholesterol determined colorimetrically. Procedure variations tested included: no saponification of total lipid extract before color development; with 15 min saponification at 80°C, with or without antioxidant protection; and with 60 min saponification at 80°C, with or without antioxidant protection. Without the saponification step, meat cholesterol values were overestimated. Samples with a large percentage of unsaturated fatty acids yielded higher cholesterol values when lipid extracts were saponified without antioxidant protection than with. Meat cholesterol values obtained by the procedure involving 15 min saponification with antioxidant protection were similar to those obtained by a commonly used gas chromatographic procedure.     

Immunochemical Quantification of Heat Denaturation of Bovine Meat Soluble Proteins

Immunoquantification of myoglobin, L-lactic dehydrogenases (LDH) M4 and H4, albumin, transferrin and immunoglobulin G (IgG) was performed after heat treatment of crude soluble sarcoplasmic protein extract over a range of 54–70°C for 30–780 min. Heat denaturation occurred in the following order: transfenin > IgG > LDH M4 > LDH H4 = myoglobin > albumin and could be described by first order reaction kinetics. The very low coefficient of variation (2–4%) of the single radial immunodiffusion technique resulted in a very weak calculated error (± 0.l–0.2°C) on temperature determination. Monitoring the concentration of LDH M4 appears appropriate for determining the minimum heating achieved in long-time, low-temperature cooking and albumin or myoglobin could be monitored for meat cooked at 69°C without holding time.     

Virucidal Effectiveness of Flexible Pouch Processing of Meat Products Prepared from Foot-and-Mouth Disease-Affected Cattle

Thermal processing of ground beef, beef cubes or beef slices in commercially popular flexible pouches, effectively inactivated foot-and-mouth disease (FMD) virus that had resulted from infection of cattle. Cooking the meat products at 75°C for 20 min or 80°C for 15 min was virucidal; however, FMD virus survived in ground beef products processed for shorter time periods and/or at lower temperatures. The processing schema described were limited to 200g samples of these meat products. Postmortem decrease of pH due to electrical stimulation of carcasses inactivated the virus in skeletal muscle but not in lymph mode tissue.     

Effect of cooking temperature and time on the physico-chemical, histological and sensory properties of female carabeef (buffalo) meat

The effect of cooking temperature (80-100°C) and time (30-60min) on collagen solubility of Semimembranosus muscle in carabeef were investigated. The pH, cooking loss, shear force value, collagen content, collagen solubility, sensory evaluation and histological observations of water bath cooked and pressure cooked Semimembranosus meat samples were measured. Increase in pH, cooking loss, collagen solubility and tenderness scores with decrease in shear force value and collagen content was observed with increases in cooking temperature and time. However, no statistical difference was observed for shear force values, collagen solubility values and tenderness scores in pressure cooked meat and meat cooked in a water bath at 100°C for 45min, inferring that cooking of buffalo meat at 100°C for 45min improved collagen solubility and tenderness to the same extent as that due to pressure cooking.     

Effects of Commercial-scale Pulsed Electric Field Processing on Flavor and Color of Tomato Juice

Effects of commercial‐scale pulsed electric field (PEF) processing on the flavor and color of tomato juice during storage at 4 deg;for 112 d were studied. Tomato juice was prepared by hot break at 88°C for 2 min and then thermally processed at 92° for 90 s or PEF processed at 40 kV/cm for 57 μs. The PEF‐processed tomato juice retained more flavor compounds of trans‐2‐hexenal, 2‐isobutylthiazole, cis‐3‐hexanol than thermally processed or unprocessed control tomato juice (P < 0.05). PEF‐processed juice had significantly lower nonenzymatic browning and higher redness than thermally processed or control juice (P < 0.05). Sensory evaluations indicated that the flavor of PEF‐processed juice was preferred to that of thermally processed juice (P < 0.01).     

Thermal inactivation of Salmonella spp. in ground chicken breast or thigh meat

Thermal inactivation of a four‐strain mixture of Salmonella spp. was determined in chicken breast and thigh meat. Inoculated meat was packaged in bags and then completely immersed in a circulating water bath and held at 55, 57.5, 60 and 62.5 °C for pre‐determined lengths of time. When the surviving bacteria were enumerated on tryptic soya agar supplemented with 0.6% yeast extract and 1% pyruvate (non‐selective medium), D‐values (time to inactivate 90% of bacteria) in chicken breast meat were 6.08, 4.77, 3.00 and 0.66 min at 55, 57.5, 60 and 62.5 °C, respectively; the values in thigh meat ranged from 11.48 min at 55 °C to 0.84 min at 62.5 °C. As expected, the measured heat resistance was lower when the recovery medium was selective (xylose lysine deoxycholate agar). Thermal death time values from this study will assist food processors in designing the HACCP plans to effectively eliminate Salmonella spp. in cooked chicken breast and thigh meat.     

Changes in Quality and Nutritional Parameters During Refrigerated Storage of an Orange Juice–Milk Beverage Treated by Equivalent Thermal and Non-thermal Processes for Mild Pasteurization

The effects of high-pressure (HP) treatment (400?MPa at 42 °C for 5 min) and pulsed electric field (PEF) processing (25 kV/cm at 57 °C for 280 μs) on ascorbic acid, total carotenoids, total phenolic compounds and total antioxidant capacity (TEAC and ORAC) of an orange juice–milk (OJ-M) beverage along the storage time at 4 °C were compared with a conventional heat preservation technology used in industry (90 °C for 15 s). During storage, ascorbic acid, total carotenoids and antioxidant capacity (TEAC) depleted with time regardless of the treatment applied. Instead, total phenolic content and antioxidant capacity measured by the ORAC method increased at the end of the storage. Non-thermal-treated beverage had less non-enzymatic browning than the thermally pasteurized one. There were no significant variations in the hidroxymethylfurfural (HMF) content of the HP- and PEF-treated OJ-M, whilst a significant increase was obtained after thermal treatment. During refrigerated storage, HMF was always below the maximum values established. The HP treatments reduced the L* value of the treated beverages immediately after processing and during refrigerated storage and induced an increase in total colour differences of beverages treated by HP compared with PEF and thermally processed orange juice–milk. Hence, alternative methods such as HP and PEF may give new opportunities to develop orange juice–milk with an equivalent shelf life to that of thermally treated orange juice mixed with milk in terms of microbial, physicochemical and nutritional characteristics.     

Optimisation of Sous Vide Processing Parameters for Pulsed Electric Fields Treated Beef Briskets

The goal of this research was to optimise sous vide processing parameters for beef briskets, previously treated with pulsed electric fields (PEF), to enhance meat tenderness while maintaining other quality attributes such as water holding capacity, colour, and collagen solubility. PEF-treated briskets (electric field strength 1.5 kV/cm; specific energy of 90–100 kJ/kg) were subjected to various sous vide temperature and time combinations for the process optimisation using response surface methodology. Sous vide temperature was found to significantly reduce the shear force of PEF-treated meat while time significantly reduced its hardness. In addition, beef briskets processed by PEF prior to sous vide processing showed less variation owing to a reduction in the effect of biological variation on the parameters tested. According to the response optimiser prediction, sous vide processing at 60 °C for 24 h resulted in optimal quality and tenderness. Scanning electron microscopy (SEM) revealed that PEF-treated meat showed evidence of pore formation in connective tissue and polarised-sensitive optical coherence topography (PS-OCT) revealed that the collagen matrix of PEF-treated meat had a reduced birefringence capacity compared to non-PEF-treated meat, which indicated a breakdown of the collagen.     

Physico- Chemical Characteristics and Functional Properties of Starch and Dietary Fibre in Grass Pea Seeds

Physico-chemical and functional properties of starch and fibre in raw and processed grass pea seeds were evaluated. Whole grass pea seeds were found to contain 41 % starch and 17% total dietary fibre (2% soluble and 15% insoluble) on dry matter basis. Examination by using scanning electron microscopy revealed oval shaped starch granules with an average width of 17 μm and length of 25 μm. Raw sample had a gelatinization onset temperature of 62°C and two endothermic transition peaks at about 73°C and 94°C, in addition the starch isolated from grass pea flour was shown to have a transition enthalpy (ΔH) of 10 Jg⁻¹. The viscosity of the raw sample (using a Brabender amylograph) reached peak maximum at 80–95°C, decreasing during the 30 min holding time (at 95°C) followed by an increase during cooling to 50°C. Raw whole seed flour was shown to have a water absorption and water solubility index (WSI) of 3 and 16%, respectively. Samples that had been cooked for 60 min had a lower WSI than those cooked for 30 min; this was further reduced in the samples cooked after soaking. The carbohydrate extracted from raw flour was found to be mainly high Mwt carbohydrate (55%), eluted at Kav < 0.2.