Availability of lactoferrin as a natural solubilizer of iron for food products

Lactoferrin (LF) was investigated as a natural solubilizer of iron. Under neutral conditions, 1 mole of LF solubilized 200 moles of iron. In a single dose oral toxicity study, 2.5 g iron solubilized by lactoferrin (FeLF) per kg body weight had no side effects on the rat gastric mucosa, while ferrous sulphate and ferrous citrate (at the same level with respect to iron) caused some serious injuries. FeLF was orally administered to rats for 28 days to investigate its potential toxicity. Haemoglobin content and its regeneration efficiency in rats fed with FeLF were superior to those observed with ferrous sulphate, which is the most frequently used iron supplement. The availability of FeLF in a rat model of iron-deficiency anaemia was demonstrated. LF is useful as a natural iron solubilizer for food products and neutraceuticals from the viewpoints of safety, bioavailability, and productivity.     

Effects of Sesame Oil Addition to Soybean Oil During Frying on the Lipid Oxidative Stability and Antioxidants Contents of the Fried Products During Storage in the Dark

ABSTRACT: Effects of sesame oil addition to soybean oil during frying on the lipid oxidative stability and antioxidants contents of fried products during storage in the dark were studied. Flour dough pieces (2 cm × 2 cm × 0.1 cm) were fried at 160 °C for 1 min in sesame oil-added soybean oil. Concentrations of sesame oil in the frying oil were 0%, 10%, and 20% by volume. Fried products were put into a glass bottle, and the bottles were tightly sealed and stored at 60 °C in the dark for 18 d. Lipid oxidation of fried products was determined by fatty acid composition changes and conjugated dienoic acid (CDA) and p -anisidine (PA) values. Tocopherols and lignan compounds in the fried products were determined by high-performance liquid chromatography. Relative content of linolenic acid decreased, and CDA and PA values increased during storage of the fried products in the dark. Fatty acid composition change and CDA and PA values during storage were lower in the products fried in sesame oil-added soybean oil than in the products fried in soybean oil without sesame oil. The results clearly showed that addition of roasted sesame oil to soybean oil at 10% and 20% during frying decreased the lipid oxidation of fried products during storage in the dark for 18 d by extension of induction period and decrease in decomposition of oxidized lipids. Fried products contained 134 to 267 ppm tocopherols and 0 to 148 ppm lignans before storage; however, their contents decreased during storage in the dark. Lignan compounds were more stable than tocopherols, and the rate of tocopherols degradation was lower in the products fried in sesame oil-added soybean oil than in the products fried in soybean oil without sesame oil, which could be because of protection of tocopherols from degradation by lignan compounds.     

RELATIONSHIP BETWEEN COMPOSITION AND STABILITY OF SAUSAGE-TYPE EMULSIONS

SUMMARY— A laboratory technique for the preparation of small batches of sausage emulsion was developed for a comparative study of the effectiveness of fresh and frozen beef in achieving emulsion stability. The technique consisted of three basic steps: (1) low speed chopping and blending of ingredients at −2° to +2°C; (2) low speed blending with the gradual addition of soybean oil at 2°−8°C; and (3) high speed chopping to a temperature of 15°-16°C. The preparation and evaluation of emulsions with widely varying compositions revealed that the lean and fat percentages could be varied over wide ranges without significantly affecting emulsion stability, but the range for percentage of water was narrow and critical to stability. The relative stability for fresh and frozen lean was influenced by the amount of added water. For example, at 30% fat level, there was a sharp drop in stability as the added water was reduced below 16% for fresh beef; whereas, an equivalent drop in stability was found as the added water was reduced below 21 % for frozen beef. The theory is proposed that emulsion instability is highly dependent upon the level of added water based on results of this investigation.     

Storage stability of traditional Tunisian butter oil produced from spontaneous fermentation of cow's milk

Physicochemical characteristics of traditional Tunisian butter (TTB) and thermal stability of the butter oil were studied. Thermal stability of samples was estimated by using the accelerated shelf life testing method. Effect of heating on some quality characteristics of traditional Tunisian butter oil (TTBO) was investigated and compared at different temperatures (60°C, 100°C and 130°C). Induction period of sample heated at 60°C was important compared to that at 100°C and 130°C. This result may indicate the sensitivity of TTBO to elevated temperature. Absorption at 232 and 270 nm, acidity and PV increased rapidly after reaching the oxidation induction time. The temperature had a significant effect on the formation of oxidation products in traditional butter oil (TTBO). Fatty acid composition of TTBO was also changed after heating. This may explain the observed modification on some quality characteristics of TTBO such as viscosity, hardness, cohesiveness and colour. As a consequence, heat treatment produced alterations in the oxidative status of the butter oil that could affect the shelf life.     

High-Temperature Natural Antioxidant Improves Soy Oil for Frying

ABSTRACT:  The objectives of this study were to determine the frying stability of soybean oil (SBO) treated with a natural citric acid-based antioxidant, EPT-OILShield™ able to withstand high temperatures and to establish the oxidative stability of food fried in the treated oil. Soybean oil with 0.05% and 0.5% EPT-OILShield and an untreated control SBO were used for intermittent batch frying of tortilla chips at 180 °C for up to 65 h. Oil frying stability was measured by free fatty acids (FFA) and total polar compounds (TPC). Chips were aged for up to 4 mo at 25 °C and evaluated for rancid flavor by a 15-member, trained, experienced analytical sensory panel and for hexanal content as an indicator of oxidation. Oil with 0.05% EPT-OILShield had significantly less FFA and TPC than the control. The effect of EPT-OILShield was apparently retained in aged chips because hexanal levels were significantly lower in chips fried in oil with 0.05% EPT-OILShield than in chips fried in the control. Tortilla chips fried in the control were rancid after 2 mo at 25 °C at sampling times evaluated from 25 to 65 h; however, chips fried in oil with 0.05% EPT-OILShield and used for 65 h were described as only slightly rancid after 4 mo. Gamma tocopherol levels were significantly higher in the chips fried in the oil with 0.05% EPT-OILShield than in the control, helping to inhibit oxidation in the tortilla chips during storage.     

Individual and Combined Use of Rosemary and Origanum in Soybean Oil as Natural Antioxidants

Dried rosemary and origanum were added to soybean oil, individually and in combination, to determine their effect on the oxidation stability of soybean oil. Samples were stored at two different temperatures (60°C and room temperature) and oxidation was determined by peroxide value and conjugated diene value. The treated soybean oil samples showed evidence of antioxidant activity at 60°C and at room temperature. Furthermore, it was observed that the herbs stored under room temperature had a higher activity compared to those stored at 60°C.     

Iron-Lactoferrin Complex Reduces Iron-Catalyzed Off-flavor Formation in Powdered Milk with Added Fish Oil

Abstract: The iron–lactoferrin complex (FeLf) is useful for dietary iron supplementation. However, the effects of FeLf on iron‐catalyzed off‐flavors in lipid‐containing food products have not been reported. In this study, we investigated the effects of FeLf on off‐flavors development during the production and storage of powdered milk with added fish oil. Powdered milk samples were formulated with FeLf or iron (II) sulfate, then stored at 37 °C for 5 mo. A sensory evaluation revealed that FeLf delayed the development of oxidized flavor and reduced metallic taste in the powdered milk compared with iron (II) sulfate. Headspace gas chromatography–mass spectrometry analysis showed that oxidized volatile compounds, such as pentanal, hexanal, heptanal, octanal, 1‐penten‐3‐one, (Z)‐4‐heptenal, (E, E)‐2,4‐heptadienal, and (E)‐2‐octenal, were less developed in the powdered milk containing FeLf than in that containing iron (II) sulfate. Iron and lactoferrin (Lf) were retained in the high‐molecular‐weight (>10000 Da) fraction of the reconstituted FeLf‐containing powdered milk after its manufacture and storage, whereas the antigenicity of Lf was lost after ultrahigh‐temperature processing at 120 °C for 5 s. These results suggest that FeLf reduces the iron‐catalyzed off‐flavors that develop during the production and storage of powdered milk. The stable iron‐holding property of FeLf contributes to the inhibition of oxidized and metallic volatile formation, although the loss of Lf antigenicity did not affect the stability of FeLf and the iron‐catalyzed formation of off‐flavors in the powdered milk. Consequently, FeLf is a suitable candidate for the simultaneous supplementation of a single food with iron and fish oil. Practical Application: The supplementation of food products with iron and fish oil is a useful approach to redressing their inadequate intake in many populations. The iron–lactoferrin complex can protect food products against the off‐flavors caused by iron‐catalyzed lipid oxidation. Our results show that the iron–lactoferrin complex is useful for the simultaneous fortification of foods and nutraceuticals with iron and fish oil because this complex also reduces the formation of iron‐catalyzed off‐flavors in powdered milk enriched with fish oil.     

Thermoxidative stability of soybean oil by natural extracted antioxidants from rosemary (Rosmarinus officinalis L.)

This study aimed to evaluate the effects of rosemary extract, grown in Iran, on thermoxidative stability of soybean oil. Rosemary extract was added to soybean oil at a concentration of 3000 mg/kg and then heated at 180°C for 20 h. The oxidative stability index, total polar compounds, tocopherol content, and fatty acid profile were measured at intervals of 0, 10, and 20 h. The results compared with synthetic antioxidant tert-butyl hydroquinone at a concentration of 50 mg/kg. Rosemary extract could lead to higher oxidative stability index, lower polar compounds, more retention of tocopherols and the greatest amount of polyunsaturated fatty acids in soybean oil after 20 h of thermoxidation process. The tert-butyl hydroquinone showed weaker antioxidant activity than rosemary extract and there was no synergistic effect between them.     

Solid Phase Microextraction of Volatile Soybean Oil and Corn Oil Compounds

ABSTRACT: The qualitative and quantitative determination of volatile compounds in soybean and corn oils were analyzed by solid phase microextraction. Coefficients of variation and sensitivity of polydimethylsiloxane, carboxen/polydimethylsiloxane, polyacrylate, and carbowax/divinylbenzene for hexanal analysis in soybean oil were 3.2, 4.2, 7.2, and 10.7%, and 15, 30,20, and 10 ppb, respectively. Volatile compounds of soybean oil with peroxide value (PV) of 1 or 5 were extracted by polydimethylsiloxane at 60 °C for 60 min. The amount of volatile compounds of PV 5 soybean oil was 92% higher than the PV 1. Volatile compounds including 2,4-decadienal, 2-decenal, hexanal, and pentane were identified in soybean and corn oils by SPME-GC-MS and GC retention time. SPME was a simple, reproducible and sensitive method for the analysis of volatile compounds of vegetable oils. Keywords: solid phase microextraction, headspace volatile compounds, soybean oil, corn oil     

谷维素对3种食用植物油的抗氧化效果研究

从米糠油皂脚中提取纯化谷维素,按不同比例添加到大豆油、菜籽油和油茶籽油中,分别采用Schaal烘箱法和油脂氧化分析仪对3种植物油氧化稳定性进行测定,同时考察在植物油氧化过程中,谷维素对其脂肪酸组成的影响,并与常见的油脂抗氧化剂进行对比。结果表明:油脂中分别添加0.1%和0.5%谷维素均对大豆油、菜籽油和油茶籽油的氧化诱导期具有延长作用,其中对油茶籽油的作用最显著;在Schaal烘箱实验中,谷维素能够有效延缓大豆油和油茶籽油过氧化值的升高,并且对油中多不饱和脂肪酸的氧化有抑制作用,但对菜籽油的抗氧化作用不显著。     

Use of sunflower oil mixed with jojoba and paraffin oils in deep-fat frying process

The aim of the present study was to increase the stability of sunflower oil during frying process and to obtain low-calorie fried foods. Therefore, sunflower oil was mixed separately with jojoba oil and paraffin oil at ratios of 9:1 and 8:2 (v/v). The frying process was conducted at 180 ° ± 5 °C for 12 h continuous heating time. Some physico-chemical properties (refractive index, viscosity, colour, acid value, peroxide value, thiobarbituric acid test, iodine value and polymer content) of non-fried and binary fried oil systems were measured at various heating periods. The results demonstrated that mixing sunflower oil with jojoba oil or paraffin oil increased the stability and hence improved the quality of sunflower oil during frying process.     

Oxidative stability of solid fats containing ethylcellulose determined based on the headspace oxygen content

Solid fat was developed by blending fully hydrogenated soybean oil, palm oil, and canola oil, and organogels were prepared using selected solid fats and ethylcellulose. The oxidative stability of organogel was tested at 100 and 180°C using a headspace oxygen assay. Addition of ethylcellulose produced a firmer organogel solid state in selected solid fats ranging from 15.8 to 24.6% saturation at room temperature. Addition of ethylcellulose generally decreased the oxidative stability of organogels prepared using canola oil. The oxidative stability of some organogels made using solid fats changed depending on the concentration of added ethylcellulose (10 or 15%, w/w), and the oxidation temperature. Development of an organogel with a relatively low saturation and a high oxidative stability suitable as a food ingredient is possible.     

Effect of bovine lactoferrin addition to milk in yogurt manufacturing

The aim of this work was to study the effect of milk supplementation with lactoferrin of different iron saturation on the manufacturing and characteristics of yogurt. Bovine lactoferrin was added at concentrations of 0.5, 1, and 2 mg/mL in the holo (iron saturated) and apo (without iron) forms. Some physicochemical properties, such as pH, concentration of lactic acid, and texture of supplemented yogurts, were determined throughout the shelf-life period storage (28 d) at 4°C. We also evaluated the stability of lactoferrin in supplemented yogurt throughout the storage time. The supplementation of milk with bovine lactoferrin did not greatly affect the physical properties of the yogurt, though apo-lactoferrin slightly delayed the decrease of pH. This could be attributed to the partial inhibition observed on the growth of Streptococcus thermophilus. The integrity and immunoreactive concentration of lactoferrin, determined by Western blotting and noncompetitive ELISA, respectively, remained constant throughout the shelf life of yogurt.     

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.     

Lipase-mediated Acidolysis of Fully Hydrogenated Soybean Oil with Conjugated Linoleic Acid

ABSTRACT: Interesterification (acidolysis) of fully hydrogenated soybean oil (melting point = 69.9 °C) with conjugated linoleic acid (CLA) was carried out in a batch reactor at 75 °C. Lipases from Candida antarctica, Rhizomucor miehei, Pseudomonas sp., and Thermomyces lanuginosus were used at 5% (wt/wt) of the total substrate load. The lipase from Rhizomucor miehei produced the fastest reaction rates, and the greatest extent of incorporation of CLA residues in acylglycerols was achieved in 12 h. Lipases from C. antarctica and T. lanuginosus produced slower initial rates, and maximum extents of incorporation of CLA residues were achieved in 24 h. The lipase from Pseudomonas sp. produced the slowest initial rate. The corresponding maximum extent of incorporation was reached in 48 h. Differential scanning calorimetry analysis of the triacylglycerol (TAG) fractions produced by C. antarctica, R. miehei , and T. lanuginosus lipases after purification by solid phase extraction showed little variation in melting point (60.4 °C, 62.8 °C, and 60.1 °C, respectively). By contrast, the corresponding TAG fraction produced by the Pseudomonas sp. lipase melted at 48.4 °C. The positional distribution of the TAGs produced by the lipase from Pseudomonas sp. differed appreciably from those produced by the other enzymes.     

芸豆蛋白抗氧化肽组分对大豆油热氧化稳定性的影响

为了探索英国红芸豆蛋白抗氧化肽组分的抗氧化作用及对油热稳定性的影响,将不同分子量的抗氧化肽组分添加到大豆油中,利用Schaal烘箱法,在63 ℃下加速氧化15 d,研究抗氧化肽对大豆油的过氧化值、酸价、P-茴香胺、羰基价等指标的影响,并对大豆油的氧化稳定性进行评价。结果表明:从0到15 d,SO（不含肽的油）、SO-h₁（含小于1000 Da肽的油）、SO-h₂（含1000～3000 Da肽的油）的过氧化值分别由0.50增加至2.91、1.48及1.57 mmol/kg,酸价分别由0.19增加至0.41、0.37及0.38 mg/kg,P-茴香胺值分别由2.34增加至9.96、8.06及9.75 mg/kg,羰基价分别由5.59增加至14.53、11.87及11.92 meq/kg。SO的增加幅度最大,SO-h₁的增加幅度最小,以上结果均差异显著（P<0.05）。由此可见,氧化指标均随大豆油氧化时间的延长呈增加趋势,从而导致油的热稳定性下降;抗氧化肽组分的抗氧化活性与分子量有关,其中分子量<1000 Da和1000～3000 Da的组分抗氧化效果最佳。此研究为英国红芸豆蛋白抗氧化肽组分的进一步应用提供了理论依据。     

Effect of Relative Humidity on the Oxidative Stability of Microencapsulated Sea Buckthorn Seed Oil

ABSTRACT: The effect of relative humidity (RH) (20 °C: RH 11%, 54%) on oxidative stability microencapsulated sea buckthorn seed oil was studied using bulk oil as a reference. Microcapsules were prepared by spray-drying using maltodextrin-gum arabic (MD/GA) and corn starch sodium octenyl succinate derivate (HiCap) as the wall materials. The influence of the physical state of the wall material was also evaluated. Under dry conditions, the microencapsulated oils were most stable, but the oxidation of the bulk oil was accelerated. At 20 °C and at RH 11%, the peroxide value of the bulk oil exceeded 20 meq/kg within 1 wk. Microencapsulation prolonged the shelf-life of the oil from 1 wk to 2 mo at 20 °C, when the encapsulating matrix was in glassy state. In conditions in which the HiCap matrix was in a rubbery state (RH 54%, 20 °C), the oxidation proceeded very quickly, reaching a peroxide value of 20 meq/kg just after 1 wk. Caking and collapse of the microcapsule powder were observed in the rubbery state. At accelerated conditions (50 °C: RH 11%, 30%, 45%), the oxidation was noticeably fast, not only in the bulk oil but also in the MD/GA matrix, even in the glassy state. The behavior in the HiCap matrix was more complex as the amount of peroxides started to decrease in time. This was assigned to the structural collapse in HiCap microcapsules. The behavior of the microencapsulated oils under accelerated conditions did not correlate with their behavior at 20 °C.     

磷脂含量对大豆油贮藏稳定性的影响

研究不同磷脂含量对大豆油贮藏稳定性的影响,采用不同磷脂添加量(2.5%、2.0%、1.5%、1.0%)的一级大豆油模拟磷脂含量不同的大豆油,在65℃条件下进行贮藏实验,检测贮藏过程中大豆油品质的变化。结果表明：大豆油在贮藏过程中折射率有一定上升;磷脂含量对大豆油酸值影响较小;磷脂含量高的大豆油过氧化值和p-茴香胺值的增长速度较慢。说明磷脂有抑制氧化酸败的作用,从贮藏角度考虑,大豆油脂中磷脂的存在对大豆油的贮藏是有利的。     

Oxidative Stability of Soybean and Sesame Oil Mixture during Frying of Flour Dough

ABSTRACT: Effects of roasted sesame seed oil on the oxidative stability of soybean oil during frying of flour dough at 160 °C were studied by determining fatty acid composition and conjugated dienoic acid (CDA), p -anisidine (PA), and free fatty acid (FFA) values. Concentration of sesame oil in frying oil was 0%, 10%, 20%, or 30% (v/v). Tocopherols and lignan compounds in the frying oil were also determined by high-performance liquid chromatography. As the number of fryings performed by the oil increased, linolenic acid content in frying oil decreased, and the decreasing rate was lower in frying oil containing sesame oil than in the oil containing no sesame oil. CDA and FFA values of frying oil increased during frying and their relative values to the initial value were lower in frying oil containing sesame oil than in the oil containing no sesame oil. This indicates that the addition of sesame oil improved thermooxidative stability of frying oil, possibly due to the presence of lignan compounds in sesame oil. Tocopherols and lignan compounds in frying oil decreased during frying. As the amount of sesame oil in frying oil increased, degradation of tocopherols increased and lignan compounds degradation decreased. Tocopherols were suggested to protect lignan compounds in sesame oil from decomposition during frying.     

Effects of soybean oil and oxidized soybean oil on the stability of β-carotene

The effects of 1.0%, 2.5%, and 5.0% purified soybean oil and thermally oxidized soybean oil on the stability of 100 ppm β-carotene as a fat-soluble vitamin A and singlet oxygen quencher in isooctane have been studied. The samples were stored under 1000, 2000, or 4000 lx at 20 °C for 2 days and at 50 °C for 16 days in the dark. The β-carotene was determined by high-performance liquid chromatography. The centrifugation and filtration of vegetable mixture, during sample preparation for β-carotene analysis by HPLC, decreased the coefficient of variation from 4.13% to 1.02%. The purified soybean oil and thermally oxidized soybean oil stabilized β-carotene in isooctane under light and in the dark at α = 0.05. The losses of β-carotene, with 1.0% purified oil, 1.0% thermally oxidized oil and without any oil during 48 h under light, were 11.2%, 80%, and 100%, respectively. 100 ppm TBHQ had a protective effect on the stability of β-carotene in isooctane at α = 0.05. The β-carotene stability decreased as the light intensity increased from 1000 to 2000 or 4000 lx at α = 0.05. The stability of vitamins in fruit and vegetable drinks enriched with fat-soluble vitamins and antioxidants during storage can be greatly improved by adding approximately 1.0% high quality non-oxidized soybean oil.