Effect of Irradiation on Antibotulinal Efficacy of Nitrite

Ground pork meat was cured with the addition of 0, 50, 100, 156, and 200 mg/kg NaNO₂, pasteurized and irradiated with 0, 3, 6, 9, 10, 20, 30, 40, and 50 kGy. After irradiation the samples were inoculated with a mixture of Clostridium botulinum type A, B and E spores, incubated at 30°C for 28 days and tested for the presence of botulinal toxin. Doses up to 9 kGy caused a decrease of NaNO₂ content with a corresponding decrease in antibotulinal activity. High irradiation doses resulted in a dose-dependent decrease in nitrite content with complete loss of antibotulinal activity.     

α-Tocopherol Content and Oxidative Stability of Egg Yolk as Related to Dietary α-Tocopherol

Hens fed diets with 0.0, 7.5, 15.0, 30.0, 60.0 and 120.0 mg supplemental α-tocopherol/kg feed produced egg yolks with 25,30,35,45,50 and 75 μg/g yolk, respectively. The correlation coefficient between dietary α-tocopherol (mg/kg diet) and egg yolk α-tocopherol (μg/g egg yolk) after 28 days feeding was 0.99. The supplemented dietary α-tocopherol had an effect on the α-tocopherol in egg yolk (p<0.05). The oxidative stability of yolk was determined by measuring the oxygen and volatile compounds in the headspace of bottled yolk. α-Tocopherol had an effect on the stability of yolk as an antioxidant at 25, 45 and 50 μg/g yolk and a prooxidant at 75 μg/g or above (p<0.05). The addition of 60.0 mg α-tocopherol/kg diet resulted in the best egg yolk stability. The correlation coefficient between headspace oxygen disappearance and volatile compound formation in the headspace of bottled egg yolk was 0.84.     

Inhibition of Oxidative Flavor Changes in Meat by α-Tocopherol in Combination with Sodium Tripolyphosphate

The effects of α‐tocopherol at 0.03%, sodium tripolyphosphate (STP) at 0.3%, alone and in combination, and STP alone at 0.5% on hexanal and sensory attributes of refrigerated cooked ground turkey or pork, with and without salt (1% NaCl), were studied. For turkey, a combination of α‐tocopherol with 0.3% STP was nearly as effective as 0.5% STP. Turkey and meaty flavor of samples from these 2 treatments did not decline; hexanal content and staleness scores remained low throughout storage. Slick mouthfeel and metallic aftertaste were less for turkey with the antioxidant combination than with 0.5% STP. In pork, STP alone at 0.3% adequately prevented oxidative flavor changes. α‐Tocopherol, when used with STP, provided no additional effect.     

Antibotulinal Activity of Methyl and Ethyl Fumarates in Comminuted Nitrite-Free Bacon

Mono- and dimethyl and ethyl esters of fumaric acid were evaluated for their antibotulinal efficacy in cans of comminuted nitrite-free bacon. At 0.125%, all were equal or superior to 120 ppm nitrite in preventing toxin formation in cans incubated at 30°C for 8 wk. No cans swelled or became toxic when mono- or dimethyl fumarate was added. With monoethyl fumarate, two cans out of twenty swelled but were nontoxic. The least effective ester was diethyl fumarate but its activity was equal to that of 120 ppm nitrite.     

Prooxidant Activity of Oxidized α-Tocopherol in Vegetable Oils

ABSTRACT:  The effect of oxidized α-tocopherol on the oxidative stabilities of soybean, corn, safflower, and olive oils and the oxidation of oleic, linoleic, and linolenic acids were studied. The 0, 650, 1300, and 2600 ppm oxidized α-tocopherol were added to soybean, corn, safflower, and olive oils and 10000 ppm oxidized α-tocopherol to the mixture of oleic, linoleic, and linolenic acids. Samples in the gas-tight vials were stored in the dark for 6 or 35 d at 55 °C. The oxidative stabilities of oils were determined by headspace oxygen with GC and peroxide value. Fatty acids were determined by GC. As the concentration of oxidized α-tocopherol in soybean, corn, safflower, and olive oils increased, the depletion of headspace oxygen and the peroxide values of oils increased during storage. The prooxidant effects of oxidized α-tocopherol on soybean and corn oils with about 55% linoleic acid were greater than those on safflower and olive oils with about 12% linoleic acid, respectively ( P  < 0.05). The changes of fatty acids during storage showed that the oxidation ratios of oleic, linoleic, and linolenic acids were 1 : 2 : 3, 1 : 12 : 26, and 1 : 8 : 16 after 5, 30, and 35 d of storage, respectively. The oxidation of α-tocopherol in oil should be prevented and the oxidized α-tocopherol should be removed to improve the oxidative stability of oils.     

Effect of α-Tocopherol, β-Carotene, and Sodium Tripolyphosphate on Lipid Oxidation of Refrigerated, Cooked Ground Turkey and Ground Pork

ABSTRACT α-Tocopherol and β-carotene at 0.03% levels and sodium tripolyphosphate (STP) at 0.2% and 0.3% levels, alone and in combination, were added to ground turkey and ground pork. Hexanal was measured after cooking and storage at 4 °C for 2, 4, or 6 d. α-Tocopherol alone significantly reduced hexanal of stored, cooked, turkey but had no effect in pork. STP was more effective than α-tocopherol and a combination of α-tocopherol with STP resulted in enhanced antioxidant activity. Hexanal of pork with 0.03%α-tocopherol plus 0.3% STP did not increase significantly during storage, and that of turkey increased only slightly. β-Carotene and salt (1% NaCl) had no effect on hexanal.     

Blood Fraction Effects on the Antibotulinal Efficacy of Nitrite in Model Beef Sausages

Toxin production by Clostridium botulinum was studied in a model cured beef sausage containing 0–5% added dried bovine blood fractions. Controls which contained nitrite but without blood fractions, were toxic by bioassay in 3 wk at 27°C. Controls without nitrite or blood fractions were toxic at 1 wk, while model sausages supplemented with hemoglobin, red cells, or whole blood were toxic in 1–3 wk. Plasma yielded no detectable toxin for 4 to > 10 wk depending upon addition level. Sausages showing delayed toxigenesis had pH values lower than those which developed toxin earlier. These results demonstrated that use of blood fractions that increased iron levels in beef above 30 μ.g/g interfered with the antibotulinal efficacy of sodium nitrite.     

Further Studies on the Antibotulinal Effectiveness of Nisin in Acidic Media

The antibotulinal effectiveness of nisin in TPYG broth was increased somewhat by lowering the pH to pH 5.5. The ability of nisin to inhibit the outgrowth of strain 56A spores was markedly increase at pH 5.5 by comparison to its effectiveness at higher pHs observed in previous studies. The increased effectiveness of nisin at pH 5.5 was less notable for the strain 69A, 113B, and 213B spores. The nisin sensitivity of the type E spores was essentially unchanged from that observed in earlier studies at higher pHs. At pH 6, nisin levels of 5000 I.U./ml were insufficient to prevent spore outgrowth by C. botulinum in cooked meat medium. Comparatively, much lower levels of nisin were effective in preventing botulinal outgrowth in TPYG broth at pH 6. The decreased effectiveness of nisin in cooked meat medium may be due to the binding of nisin to meat particles, and this binding is apparently not affected by lowering the pH to pH 6.0.     

Effects of Ascorbic Acid and α-Tocopherol on Antioxidant Activity of Polyphenolic Compounds

The effects of ascorbic acid and α‐tocopherol on the antioxidant activity of 15 phenolic compounds were compared with 2 in vitro assays. Combination of ascorbic acid or α‐tocopherol plus polyphenolic compounds resulted in an additive effect as shown with DPPH–HPLC method. With the liposome oxidation method, combination of quercetin or catechins plus α‐tocopherol showed synergistic effects.     

天然植物提取物替代亚硝酸钠对中式培根特性的影响

在中式培根加工中用天然植物提取物T10 PLUS替代亚硝酸钠,以添加亚硝酸钠的常规产品作为对照,研 究天然植物提取物替代亚硝酸钠对产品特性的影响。结果表明：在实验期内,实验组和对照组产品均呈现较好的红 度值和外观色泽,而亚硝酸钠的护色作用比天然植物提取物稍佳;添加亚硝酸钠产品的抑制酸败和抗氧化能力略 强,但与添加天然植物提取物的产品无显著差异;亚硝酸钠表现出略优于天然植物提取物的抑菌效果,但在产品冷 藏的25 d内差异不显著;亚硝酸钠组产品的色泽指标更佳,其他指标未见显著差异。     

Effects of Dietary Oils and α-Tocopherol Supplementation on Membranal Lipid Oxidation in Broiler Meat

The effects of different dietary oils and α-tocopherol on the fatty acid composition of mitochondrial and microsomal lipids of broiler muscle and their lability to NADPH-induced peroxidation were investigated. Fatty acid composition of both neutral lipids and phospholipids of mitochondria and microsomes was influenced by dietary oil composition. Supplementation of the diet with α-tocopherol only appeared to increase the α-tocophcrol concentration in the microsomal membranes in the dark meat. The rate of NADPH-induced lipid peroxidation in microsomes and mitochondria was dependent primarily on the fatty acid composition of the membrane lipids, and, to a lesser extent, on the α-tocopherol content.     

Inhibition of N-Nitrosopyrrolidine in Dry Cured Bacon by α-Tocopherol-Coated Salt Systems

Dry cured bacon was made under carefully controlled processing conditions in a pilot plant study using α-tocopherol-coated salt as part of the dry cure. Approximately, a 96% reduction in N-nitrosopyrrolidine (NPYR) levels in the fried bacon was achieved with an ingoing α-tocopherol level of 500 mg/kg. NPYR levels in the cookout fat were reduced approximately 92% using the same level of α-tocopherol. Bacon, prepared by a small scale commercial operation, also contained reduced levels of NPYR when processed with α-tocopherol-coated salt, despite high levels (>100 mg/kg) of residual sodium nitrite in the finished bacon. Results comparing effectiveness of α-tocopherol and mixed tocopherols as nitrosamine blocking agents were inconclusive. Although, α-tocopherol appeared to be more effective as a blocking agent (91% versus 73% inhibition of NPYR), the difference in percent inhibition achieved could possibly be attributed to apparently lower levels of residual mixed tocopherols in the finished bacon.     

3种活性成分对低温香肠中亚硝酸钠残留的影响

肉制品中残留亚硝酸盐对人体健康有害。本试验中将苹果多酚、红景天提取物和银杏黄酮添加至香肠中,研究它们对亚硝酸钠残留量的影响。采用分光光度法测定香肠中亚硝酸钠的残留量,用色差仪测定香肠的色差,结合感官评定确定苹果多酚、红景天提取物和银杏黄酮的最佳添加范围。通过正交试验,确定这3种物质的最佳混合比例。试验结果表明:随着功能成分添加量的增加,香肠中亚硝酸钠残留量逐渐降低;将0.3g/kg苹果多酚、2.5g/kg红景天提取物和1.2g/kg银杏黄酮混合添加到香肠中,降低亚硝酸钠残留量的效果最好,其残留量仅为0.0158g/kg。     

Oxidative Reactions of Model Maillard Reaction Products and α-Tocopherol in a Flour-Lipid Mixture

Nondialyzable model Maillard reaction products (MRPs) were prepared by heating 0.8M D-glucose or D-fructose with 0.8M L-lysine under different reaction conditions and times. The usefulness of derived MRPs, with highest melanoidin yields, in stabilizing oxidative deterioration in food was evaluated in a flour-lipid dough mixture with or without cupric ions. Glucose-lysine MRPs effectively reduced lipid oxidation both with and without cupric ions. In contrast, fructose-lysine MRPs lowered lipid oxidation only without cupric ions, and accelerated lipid oxidation with cupric ions. Application of MRPs in combination with α-tocopherol showed no synergistic or antagonistic effect. Conditions and type of reducing sugar in synthesis of MRPs can influence their anti- or pro-oxidant activity.     

Thiamin, Riboflavin and α-Tocopherol Retention in Processed and Stored Irradiated Pork

Combination treatments for preservation of irradiated pork were investigated with respect to vitamin loss. Ground pork was prepared under nitrogen and packaged in anaerobic foil. The samples were enzyme denatured by heating before and after irradiation, then cooked and stored. Irradiation resulted in thiamin loss, but neither riboflavin nor α-tocopherol was affected. Neither thiamin nor riboflavin was affected by heat denaturation, cooking or storage, but heating and cooking increased the measured α-tocopherol. The lack of loss of the vitamins was attributed to the exclusion of oxygen.     

Storage Stability of α-Tocopherol in a Dehydrated Model Food System Containing Methyl Linoleate

The storage stability of α-tocopherol in a dehydrated model food system containing methyl linoleate was evaluated. The degradation rate of α-tocopherol was best described by zero order kinetics with rates significantly greater than 0 (p≤0.002), correlation coefficients (|R|)≤0.88 and standard deviations from 4–13% of the reported rate constants. The zero order rate constants were dependent on the initial α-tocopherol concentrationn, indicating that the concentration of α-tocopherol and unknown reactant(s) does affect the storage stability of α-tocopherol. The storage parameters of water activity, storage container oxygen content, and storage temperature affected the rate of α-tocopherol loss indicating that these parameters must be controlled to maximize α-tocopherol storage stability.     

亚硝酸盐对猪肉腌制过程中颜色的影响

亚硝酸盐是腌腊肉制品中常用的食品添加剂,具有发色、抑菌、改善风味和质构等作用。文中通过感官评分、色差计、发色率和肌红蛋白含量测定,对猪肉腌制过程中颜色受亚硝酸钠添加量的影响作了初步研究,发现不同亚硝酸钠添加量的猪肉在腌制过程中,各项颜色指标发生了显著变化。通过不同方法之间的相关分析,发现CIEa*值与感官评分、发色率、肌红蛋白总量之间的相关性较好(分别为r=0·91、r=0·92、r=0·72)。     

Sensory, Physical, and Cooking Characteristics of Bacon Processed with Varying Levels of Sodium Nitrite and Potassium Sorbate

Sensory, physical, and cooking properties were evaluated on bacon processed under commercial operations in four separate plants. Three formulations with various levels of sodium nitrite and potassium sorbate were used: (1) 0 ppm sodium nitrite, (2) 40 ppm sodium nitrite 2600 ppm potassium sorbate, and (3) 120 ppm sodium nitrite. Sliced bacon was evaluated after 10, 30, 50, and 70 days of storage. “Chemical”-like flavors, prickly mouth sensations, and “sweet aromatic” aromas were found in bacon processed with 40 ppm sodium nitrite and 2600 ppm potassium sorbate. “Microbial” flavors were found in 0 ppm sodium nitrite bacon after 50 and 70 days of storage. Bacon stored for 30 days had less cooking loss and sensory panel scores indicative of more mouth coating with fat than did bacon stored for 10 days. The degree of leanness in bacon strips had more of an influence on textural, physical, and cooking characteristics than did sodium nitrite and potassium sorbate levels.     

钠盐内注-外涂添加对减钠盐传统培根滋味的影响

基于培根的减盐化加工工艺,在钠盐使用量1.5％水平下,研究内注-外涂钠盐添加方式对减钠盐培根钠离子释放量、游离氨基酸含量、5'-呈味核苷酸含量、等效鲜味浓度及滋味感知的影响.结果表明:内注-外涂添加方式可减少减钠盐生培根烤制期间5'-呈味核苷酸的损失,增加游离氨基酸的释放,提高其等效鲜味浓度,显著加快培根咀嚼过程早期钠...     

Color Stability and Microbial Growth Relationships in Beef as Affected by Endogenous α-Tocopherol

Longissimus muscle from Holstein steers supplemented with vitamin E at 500 or 2000 mg/head/day showed less surface metmyoglobin accumulation than controls during 12 days storage at 4°C. Temperature abuse at 25°C for 24 hr increased metmyoglobin formation; vitamin E supplementation diminished the adverse effect of temperature abuse. No differences (P > 0.05) in bacterial load were observed among the 3 vitamin E treatments during storage. Sensory panelists preferred vitamin E-supplemented beef steaks in visual acceptance. Panelist assessment of discoloration correlated highly with a value and hue angle. In general, elevated α-tocopherol concentrations in beef steaks did not affect panelist assessment of meat spoilage.