Stability of α-Tocopherol, Thiamin, Riboflavin and Retinol in Pork Muscle and Liver during Heating as Affected by Dietary Supplementation

The α-tocopherol (Vit E) and ascorbic acid (Vit C) supplementation of pig diets increased (P<0.05) liver α-tocopherol concentrations. After heating, the liver samples of both treated groups and the longissimus dorsi muscle samples of the vitamin C group showed increased riboflavin retention (P<0.05). The supplemented and control groups did not show differences regarding retention of α-tocopherol, retinol and thiamin in heated liver and longissimus dorsi. Dietary vitamin C resulted in higher liver vitamin E and was most effective in protecting riboflavin against loss during heating of liver or longissimus dorsi.     

α-Tocopherol, β-Carotene and Ascorbic Acid as Antioxidants in Stored Poultry Muscle

Broilers were fed α-tocopherol or β-carotene for 3 wk or L-ascorbic acid for 24 hr prior to slaughter. α-Tocopherol maintained the redness of unheated meat stored for 8 wk (—20°C). Values for thiobarbituric acid reactive substances in ground, stored meat showed that L-ascorbic acid produced results similar to the control while a-tocopherol produced results lower than the control. Panelists rated meat with added α-tocopherol as different from the control for smell and flavor. β-Carotene was a pro-oxidant compared to the control and other additives. Meat from broilers fed β-carotene had lower α-tocopherol content than the control. Vitamin A in livers of birds fed β-carotene was 64% higher than that of the control.     

Gamma Irradiation Effects on Thiamin and Riboflavin in Beef, Lamb, Pork, and Turkey

A study was made of the loss of thiamin and riboflavin due to gamma irradiation of beef, lamb and pork longissimus dorsi, turkey breast and leg muscles. Thiamin losses averaged 11%/kiloGray (kGy) and riboflavin losses 2.5%kGy above three kGy. The rate of loss of thiamin in beef was higher than that in lamb, pork and turkey leg, but not turkey breast. with losses of 16%/kGy in beef and 8%/kGy in lamb. The rate of thiamin loss was not related to sulfhydryl, protein, moisture, fat or water content, pH or reducing capacity by redox titration. Loss of riboflavin was not different among species. Any detriment from such slight losses would seem to be more than compensated by the advantage of controlling bacteriological contamination by irradiation processing.     

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.     

Stability of α-, γ-, or δ-Tocopherol during Soybean Oil Oxidation

ABSTRACT:  The decomposition of α-, γ-, or δ-tocopherol in soybean oil during 24 d of storage at 50 °C was determined by high performance liquid chromatography (HPLC). The initial contents of α-, γ-, and δ-tocopherol in soybean oil were 53, 750, and 268 ppm, respectively. The degradation rates of α-, γ-, and δ-tocopherol for the first 10 d were 5.6%, 1.2, and 0.5% per day, respectively. The α-tocopherol was completely destroyed in 16 d. The destructions of γ- and δ-tocopherol were 28% and 17% after 24 d. The induction period of soybean oil determined by headspace oxygen, conjugated diene, and peroxide value was 8 d. As the degradations of α-, γ-, and δ-tocopherol increased, the headspace oxygen disappearance, conjugated diene formation, and peroxide value of soybean oil increased. The correlation coefficient between the degradation of tocopherols and the oxidation of soybean oil was about 0.95. The degradation of tocopherols in soybean oil during storage was due to the oxidation.     

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.     

α-Tocopherol and Ascorbate Delay Oxymyoglobin and Phospholipid Oxidation In Vitro

An oxymyoglobin liposome model was used to study the effects of α-tocopherol and/or ascorbate upon oxymyoglobin and lipid oxidation. Both oxidations were delayed (P<0.05) by increased concentrations of α-tocopherol alone and α-tocopherol/ascorbate relative to controls. The 14 μ Mα-tocopherol/140 μM ascorbate treatment resulted in greatest delay in both oxymyoglobin and lipid oxidation. Ascorbate alone delayed oxymyoglobin oxidation; effectiveness diminished as ascorbate increased. Ascorbate showed a prooxidant effect toward lipid oxidation which was unchanged in the presence of EDTA. Results support the hypothesis that α-tocopherol retards lipid oxidation directly and OxyMb oxidation indirectly.     

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.     

Dietary Pigmentation and Deposition of α-Tocopherol and Carotenoids in Rainbow Trout Muscle and Liver Tissue

Rainbow trout (Oncorhynchus mykiss) were fed diets supplemented with canthaxanthin, oleoresin paprika and α-tocopherol. Canthaxanthin was more efficiently absorbed (3.8–7.9 mg/kg) in the flesh of rainbow trout than the paprika carotenoids (2.4–3.1 mg/kg). With increased pigmentation, decrease in lightness (L*) and hue angle, and increase in redness (a*) of the muscle were observed. Canthaxanthin produced more desirable reddish-pink color. Deposition of α-tocopherol in liver and muscle tissue increased with increase in dietary α-tocopheryl acetate. Fish receiving lower α-tocopheryl acetate reached maximum deposition levels earlier than those fed higher levels. There was no effect of α-tocopherol and carotenoid levels on muscle fatty acid composition.     

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.     

Oxymyoglobin and Lipid Oxidation in Phosphatidylcholine Liposomes Retarded by α-tocopherol and β-carotene

An n-3 fatty acid-constructed oxymyoglobin liposome model was used to study the effects of 10 μM α-tocopherol and/or various concentrations of β-carotene on oxymyoglobin and lipid oxidation. Oxidation was delayed by α-tocopherol or β-carotene treatments alone (p < 0.05). β-Carotene at 1.5 μM and 2μM caused greater delay in oxymyoglobin oxidation than α-tocopherol (p < 0.05). For lipid oxidation inhibition, 2 μM β-carotene was similar in effect to α-tocopherol. With α-tocopherol plus 1.5 or 2 μM β-carotene, greater oxidation delaying effect resulted for both oxymyoglobin and lipid oxidations than with 1.5 or 2 μM β-carotene treatment alone (p < 0.05).     

Influence of Dietary Supplementation with α-Tocopheryl Acetate and Canthaxanthin on Cholesterol Oxidation in ω3 and ω6 Fatty Acid-enriched Spray-dried Eggs

ABSTRACT: The effect of feeding laying hens linseed oil or sunflower oil, with and without α-tocopheryl acetate and/or canthaxanthin, was evaluated on cholesterol oxidation in spray-dried whole egg at various storage periods. Storage of spray-dried eggs at room temperature in the dark resulted in an increase in cholesterol oxidation products from 18.1 μg/g, after spray drying, to 39.3 μg/g, at 12 mo of storage. No differences were found with either dietary oil or canthaxanthin supplementation. However, α-tocopheryl acetate supplementation resulted in a lower formation of cholesterol oxidation products during storage. No synergistic effect between α-tocopherol and canthaxanthin was detected.     

Quenching Mechanisms and Kinetics of α-Tocopherol and β-Carotene on the Photosensitizing Effect of Synthetic Food Colorant FD&C Red No. 3

ABSTRACT: Effects of FD&C Red No. 40, Red No. 3, Yellow No. 5, Yellow No. 6, Green No. 3, Blue No. 1 and Blue No. 2 on 0.03M soybean oil oxidation in acetone at 25 °C under light were studied by measuring headspace oxygen depletion. As Red No. 3 increased from 0 to 5, 20, 100 and 200 ppm, the headspace oxygen was reduced by 2 to 70, 73, 77 and 77%, respectively, for 4 h. Only Red No. 3 acted as a photosensitizer to produce singlet oxygen in the oil. The quenching rates of α-tocopherol and β-carotene for the singlet oxygen by Red No.3 were 4.1 × 10⁷ M⁻¹s⁻¹ and 7.3 × 10⁹ M⁻¹s⁻¹, respectively. When β-carotene was below 1.86 × 10⁻⁶ M, β-carotene quenched singlet oxygen, but it quenched both singlet oxygen and Red No. 3 at or above 3.72 × 10⁻⁶ M. However, α-tocopherol quenched singlet oxygen only.     

Specific Disulfide Bond in α-Lactalbumin Infiuences Heat- Induced Gelation of α-Lactalbumin-Ovalbumin-Mixed Gels

The gel strength of ovalbumin mixed with α-lactalbumin (α-La) was determined after heating at 80°C for 15 min at pH 7.0 Gel strength of the mixture of 4%α-La and 4% ovalbumin was two times that of 8% ovalbumin. Modified α-La at Cys6-Cys120 (3 SSα-La) had low enhancement effects on ovalbumin gelation. Competitive ELISA using monoclonal antibody to α-La showed decreased binding reactivities after heating α-La with ovalbumin at specific concentrations. The decrease of total SH groups in the gel mixed with 3SS α-La was much less than when mixed with α-La. A disulfide bond of Cys6-Cys120 in α-La contributed to interactions between ovalbumin and α-La in heat-induced gels.     

Quantitative X-Ray Diffraction Determination of α-Lactose Monohydrate and β-Lactose in Chocolate

ABSTRACT:  Lactose is a constituent of milk chocolate. During processing and cooling, lactose may precipitate as α-lactose monohydrate and β-lactose. The presence of α-lactose monohydrate has a deleterious effect on the quality of milk chocolate. A quantitative X-ray diffraction method for determination of α-lactose monohydrate and β-lactose in chocolate is described. The α-lactose monohydrate signal at 19.9°2θ with Cu-Kα X-rays is a cubic function of concentration. The β-lactose signal at 20.9°2θ is a linear function of concentration. α-Lactose monohydrate is detectible at about 0.1 weight% and can be quantified at >0.5 weight%. β-Lactose is detectible at about 1 weight% and can be quantified at >3 weight%. About 10 min is required to prepare and run a sample.
Practical Application: The crystalline form of lactose affects the quality of chocolate. A rapid method for quantifying crystalline forms of lactose in chocolate is described. The method can be used for quality control and for improving chocolate quality.     

Formation of α-terpineol in Citrus Juices, Model and Buffer Solutions

The formation of α-terpineol from its putative precursors in citrus juice (d-limonene and linalool) was investigated in juice, buffers and model solutions. α-Terpineol content was higher in commercial lemon juice than in orange or grapefruit juices. Its content exceeded its taste threshold of 2.5 mg/L in orange juice stored for 1 month at 35 °C. During storage of homogenized model solutions fortified with d-limonene or linalool, α-terpineol was simultaneously formed and degraded, especially at 45 °C and its formation was strongly dependent on pH. Linalool was a more reactive substrate than limonene for α-terpineol formation; the protonation in linalool was faster than in limonene. However, since there was more limonene than linalool in citrus juices, a-terpineol appeared to have been formed to about the same extent from both precursors.     

Selective Solubilization of α- Lactalbumin and β-Lactoglobulin into Reversed Micelles from Their Mixtures

Phase transfer experiments were performed, involving contact between an aqueous 1:1 solution of α-lactalbumin and β-lactoglobulin and an AOT-in-isooctane reversed micellar phase. The resulting extraction and separation of the two proteins were analyzed as functions of pH, ionic strength and total protein concentration using SDS-PAGE, and compared with extractions from pure solutions. At low protein concentrations, the extent of reversed micellar solubilization of the two pure proteins predicted well the extraction from mixtures. However, at higher protein concentrations β-lactoglobulin appeared to be excluded from the micellar droplets. Because of the significantly different partitioning behavior of the two proteins, reversed micellar extraction from an initially equal weight mixture led to an effective separation of the proteins.     

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.     

Modeling Thermal and Mechanical Effects on Retention of Thiamin in Extruded Foods

ABSTRACT: A model was proposed to predict separate thermal and mechanical effects of extrusion cooking on thiamin retention. Thermal effects were determined by heating small samples of wheat flour mixed with 0.30% (wt/ wt) thiamin hydrochloride isothermally at 140 °C, 151 °C, and 161 °C for different times. The calculated activation energy and rate constants at each temperature were 67.28 kJ/g mol and 0.00869/min, 0.0145/min, and 0.0224/min, respectively. The "extruder constant" was estimated as 27.7/rev, based on a matching-viscosity method. Wheat flour with 0.30% (wt/wt) thiamin was extruded at different screw speeds. Mechanical effects caused 89.7% to 94.4% of total thiamin loss. This research provides a generalized method to "fingerprint" the extrusion process.     

Determination of α-bisabolol and d-panthenol in cosmetic products by gas chromatography

α-bisaboloi and d -panthenol are used in many cosmetic preparations, respectively, for their anti-inflammatory and regenerating properties. Their quantitative determination was an important element of their evaluation in these emulsions. Their concentration has been determined by gas chromatographic techniques, using a flame ionization detector. In both cases, the internal standards have been chosen for their compatibility with the analysis of extracted substances.
Owing to the complexity of the cosmetic formulations, a preliminary extraction of α-bisabolol and d -panthenol was necessary. For the two substances the preparative separation was based on a liquid–liquid extraction. After dissolving the emulsion in methanol and diluting it with an aqueous buffer solution α-bisabolol was then extracted by ethyl acetate and d -panthenol by ethyl formate.