MICROSTRUCTURE of PEANUT BUTTER STABILIZED WITH PALM OIL

Free oil separation is a problem in "natural" peanut butter. Studies have indicated that palm oil functions as an effective stabilizer in peanut butter. This study was undertaken to determine the effect of palm oil on microstructural features of peanut butter. Samples containing 0, 1.5 and 2.5% palm oil and a control containing hydrogenated vegetable oils were prepared and stored at 0C and 45C for 130 days. Microstructure was examined by light microscopy. Addition of palm oil in peanut butter markedly increased spatial distribution of protein bodies and cell wall fragments when compared to nonstabilized products. Palm oil has potential as a stabilizer in peanut butter, but shelf-life stability is likely to be less than that achieved with presently used stabilizers, at elevated temperatures due to a less stable microstructure resulting in a lower level of solid dispersion in the continuous oil phase.     

ANTIOXIDATIVE AND ANTIBACTERIAL POTENTIALS OF ESSENTIAL OILS AND EXTRACTS ISOLATED FROM VARIOUS SPICE MATERIALS†

The antioxidant and antibacterial potentials of essential oils and acetone extracts of black pepper, cumin, black cumin and mace were carried out by different techniques. The antioxidative capacity of the essential oils and acetone extracts were evaluated against mustard oil by measuring peroxide and thibarbituric acid values at fixed intervals. In addition, their antioxidant potential was evaluated by 2, 2′‐diphenyl‐1‐picrylhydracyl radical and conjugated diene assays. Their reducing power was determined with standards, which proved the strong antioxidant capacity of essential oils and extracts. The antioxidant activity of essential oils and extracts exerted by all the antioxidant assays can be compared with synthetic antioxidants such as butylated hydroxyanisole and butylated hydroxytoluene. The antibacterial activity was studied by disk diffusion and poison food methods. Black cumin essential oil showed complete zone of inhibition (P < 0.05) against tested bacterial strains of Staphylococcus aureus, Bacillus cereus and Bacillus subtilis at 2 and 6 µL level by disk diffusion method. Black cumin and black pepper extracts showed complete reduction of colonies against tested bacterial strains of S. aureus, B. cereus and B. subtilisat 5 and 10 µL level by poison food method. Poison food method exhibited good results for the tested essential oils and extracts. Essential oils of black pepper, cumin, black cumin and mace may be used to stabilize mustard oil after screening.     

ANTIOXIDANT POTENTIAL OF 5-n-PENTADECYLRESORCINOL

The antioxidant potential of 5-n-pentadecylresorcinol was determined with five different oils. Alkylresordnol (AR) was added at 0.025%, 0.050% and 0.075%, respectively. For comparison, 0.01% butylated hydroxyanisole (BHA) was used as antioxidant. Oils were incubated at 10, 25 and 40C. Peroxide values were determined at different time intervals. Accelerated tests using a pro-oxidant were also conducted with each oil. AR was shown to slow oxidative rancidity of the oils.
The ability of AR to slow lipid oxidation in cereal products was also studied. Wheat bran, rye bran and whole grain millet meal were treated with 0.050% and 0.075% AR and BHA, respectively, and stored at 40C. Peroxide values were determined at different time intervals. AR was shown to slow lipid oxidation in cereal products.     

ANTIOXIDANT EFFICACY OF EXTRACTS OF AN EDIBLE RED ALGA (GRATELOUPIA FILICINA) IN LINOLEIC ACID AND FISH OIL

The antioxidant activity of an extract of a marine red alga (Grateloupia filicina) was evaluated in linoleic acid and fish oil induct period oil at 65C. Oxidative stability of the oils was evaluated by employing peroxide value (PV), 2-thiobarbituric acid reactive substances (TBARS), conjugated diene (CD) and weight gain experiments. The algal extract was applied to linoleic acid and fish oil at 0.01, 0.03 and 0.05% and results were compared with those of commercial antioxidants such as butylated hydroxytoluene (BHT), butylated hydroxyanisol (BHA) and α-tocopherol at 0.01 %. Results indicated the ability of the alga extract to inhibit oxidation of linoleic acid and fish oil; at α 0.05%     

Chemical and microbiological stability and sensorial properties of traditional Iranian butter incorporated with pomegranate peel extract

In this study, the antioxidant activity of pomegranate peel extract (PPE) and its potential effect on the chemical and microbiological stability of traditional butter was investigated. The PPE having total phenol content of 327.48 ± 1.43 mg gallic acid equivalent/g showed significantly greater (64.34 ± 0.32%) radical scavenging activity than butylated hydroxy toluene. Butter treated with PPE had significantly lower levels of peroxide value, free fatty acids, Totox, Schaal value and microbial population. The work concluded that PPE could be an excellent natural source of antimicrobial and antioxidant substances, which can be used for traditional butter preservation.     

BUTTER STABILITY AS AFFECTED BY EXTRACTS OF SAGE, ROSEMARY AND OREGANO

Effects of methanolic extracts of sage ( Salvia fruticosa L.), rosemary ( Rosmarinus officinalis L.) and oregano ( Origanum vulgare L.) on butter stability were investigated. All extracts were individually added to butter at 0.02 or 0.05%. For comparison, 0.02% butylated hydroxyanisole (BHA) and control group were also prepared and tested. The samples were stored at 25 or 5C. The peroxide value, free fatty acids and thiobarbituric acid value were determined at regular intervals for all samples. Spice extracts and their combinations exhibited a better effect than that of BHA in stabilizing butter against oxidation. The most effective extract was that of sage. The extracts significantly stabilized butter (P<0.05). Butter samples stored at 5C were more stable (P<0.05) than those kept at 25C.     

FACTORS AFFECTING MACADAMIA NUT STABILITY. 3. Effects of Roasting Oil Quality and Antioxidants

SUMMARY– Chemical and physical changes in roasting oil from a commercial processing plant and the relationship of these changes to quality and shelf-life of roasted macadamia kernels were investigated. Oil was sampled initially and after 2, 4 and 13 weeks of roasting. Generally, free fatty acid, color (absorbance at 550 nm), refractive index and viscosity of the roasting oil increased with use. Changes in iodine number and fatty acid composition indicated there was considerable oil exchange between roasting oil and macadamia kernels. Antioxidant loss in the roasting oil was rapid. No flavor differences were observed in kernels immediately after roasting in the various oil samples, and shelf-life was not appreciably affected by continuous use of the oil for as long as 13 weeks. A second study investigated the effects of vacuum-packing (0, 15 and 24 in.) and direct antioxidant application (approximately 76 ppm butylated hydroxyanisole and butylated hydroxy-toluene) on the stability of dry-roasted macadamia kernels. Stability of antioxidant-treated kernels was greater than that of untreated kernels, regardless of vacuum level. Vacuum packing had no effect on antioxidant-treated kernels, but showed some benefit for untreated kernels.     

Use of gamma radiation in sheep butter manufacturing process for shelf-life extension

Gamma-irradiated sheep cream (1 kGy) was used to produce butter that was analysed during refrigerated storage up to 90 days in shelf-life extension studies including sensory, microbiological and water content assessments. The water content of the sheep butter made with irradiated fermented cream was 10% higher than that of control butter. A slower increase in bacterial load during storage was detected for the butter manufactured with irradiated fermented sheep cream compared with control butter; however, fungi increased at similar rates in both cream-irradiated and control butters during storage. The sensory evaluation suggested, in general, the acceptance of the irradiated samples by the panellists. The microbiocidal potential of gamma radiation of fermented sheep cream was highlighted, but was not reflected in extension of shelf-life of the butter produced. The traditional manufacturing process itself was found to be a major vehicle for microbial contamination of this dairy product, preventing its shelf-life extension.     

Determination of synthetic phenolic antioxidants in food items using reversed-phase HPLC

A HPLC with gradient elution method for the determination of the synthetic phenolic antioxidants (SPAs) propyl gallate (PG), tertiary butyl hydroquinone (TBHQ), butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT) in food items is described. A C18 column served as the stationary phase; the gradient elution was formed by acetonitrile and water:acetic acid (1%). The UV detector was set at 280 nm. Under the recommended conditions, separation of the four SPAs was achieved in less than 8 min. Analytical characteristics of the HPLC method such as limit of detection, linear range, and reproducibility were evaluated. Extraction parameters were optimized for the recoveries of the SPAs in different types of food items (cooking oil, margarine and butter, and cheese). Before the HPLC separation, the SPAs were extracted with methanol/acetonitrile (1:1, v/v) and were subjected to vortex/ultrasonic treatment. The extracts were next kept in a freezer (∼2 h) to precipitate co-extracted components. Recoveries of the SPAs when spiked to cooking oil, margarine, butter and cheese at 50 and 200 mg l⁻¹ were in the ranges 93.3–108.3% for PG, 85.3–108.3% for TBHQ, 96.7–101.2% for BHA and 73.9–94.6% for BHT. The method was applied to the determination of SPAs in 38 food items (16 cooking oils, ten margarine, six butter and six cheese samples). The levels of SPAs in positive samples are all below the legal limits of Malaysia.     

Nutritional Composition of Shea Products and Chemical Properties of Shea Butter: A Review

Increasing demand of shea products (kernels and butter) has led to the assessment of the state-of-the-art of these products. In this review, attention has been focused on macronutrients and micronutrients of pulp, kernels, and butter of shea tree and also the physicochemical properties of shea butter. Surveying the literature revealed that the pulp is rich in vitamin C (196.1 mg/100 g); consumption of 50 g covers 332% and 98% of the recommended daily intake (RDI) of children (4–8 years old) and pregnant women, respectively. The kernels contain a high level of fat (17.4–59.1 g/100 g dry weight). Fat extraction is mainly done by traditional methods that involve roasting and pressing of the kernels, churning the obtained liquid with water, boiling, sieving, and cooling. The fat (butter) is used in food preparation and medicinal and cosmetics industries. Its biochemical properties indicate some antioxidant and anti-inflammatory activities. Large variations are observed in the reported values for the composition of shea products. Recommendations for future research are presented to improve the quality and the shelf-life of the butter. In addition, more attention should be given to the accuracy and precision in experimental analyses to obtain more reliable information about biological variation.     

Effect of the volatile constituents isolated from Thymus albicans, Th. mastichina, Th. carnosus and Thymbra capitata in sunflower oil

The composition of essential oils isolated from Thymus albicans and Thymbra capitata collected in Algarve (Portugal), Th. mastichina collected in Algarve and Estremadura (Portugal) and Th. carnosus also collected in Algarve, during the flowering phase, was analysed by gas chromatography (GC) and GC coupled to mass spectrometry (GC-MS). The antioxidant capacity of the oils as well as some of their main components was determined by periodic evaluation of the peroxide values in sunflower oils stored at 60 degrees C. These peroxide values were compared to that of butylated hydroxytoluene (BHT) and control (without adding antioxidants) under the same experimental conditions. The oils of Th. albicans and Th. mastichina, collected in Algarve, were dominated by 1,8-cineole (68% and 45%, respectively), whereas linalool (52%) was the main component from the oils isolated from Th. mastichina collected in Estremadura. Carvacrol (68%) was the major component present in the oils of Thymbra capitata while borneol (18%), terpinen-4-ol (11%) and camphene (9%) were the major ones in the essential oil of Th. carnosus. The essential oils as well as some of their main components showed higher antioxidant capacity than that of the synthetic antioxidant BHT. At the end of the experiment (57 days), BHT showed a percentage of inhibition of 20%, while that of the essential oils ranged from 46% for Th. carnosus, to 59% for Th. mastichina collected in Estremadura.     

Antioxidant efficacy of extracts produced from pickled and dried mustard in rapeseed and peanut oils

Antioxidant efficacy of 70% ethanol extract (EE), 70% methanol extract (ME), and water extract (WE) produced from pickled and dried mustard (Brassica juncea Coss. var. foliosa Bailey) was evaluated in rapeseed and peanut oils by using the Schaal oven method. The protective effects of aforesaid 3 extracts in stabilizing vegetable oils were tested by measuring their peroxide values, conjugated diene values, and p-anisidine values during storage of 15 d at 60 °C. Results showed that the different solvent extracts produced from pickled and dried mustard, at concentrations of 0.5% and 1.0% (w/w) in vegetable oils, could significantly (P < 0.05) lower the peroxide value, conjugated diene value, and p-anisidine value of oils during storage at 60 °C. However, the extracts at various concentrations showed a less antioxidant effect than butylated hydroxytoluene (BHT) at 200 ppm. The ultraviolet spectra of different extracts exhibited a single maximum absorbance at 268 nm. The qualitative analysis of antioxidants present in the extracts was carried out by reverse phase high performance liquid chromatography (HPLC) using a C18 column. Two phenolic compounds, gallic and protocatechuric acids, were identified. The antioxidant activity of the extracts might be attributed to the presence of these phenolics. These results indicated that the pickled and dried mustard could be used as a potential source of natural antioxidants. PRACTICAL APPLICATION: The antioxidant activity of extracts produced from pickled and dried mustard toward rapeseed and peanut oils oxidation and the characterization of active phenolic compounds may be useful in developing natural antioxidants for vegetable oils. Moreover, the extracts could safely be used as potential antioxidant to suppress lipid oxidation in lipid-containing food products.     

Interaction of packaging materials and vegetable oils: oil stability

The effects of different plastic films (polyethyleneterephthalate, polyvinylchloride, polypropylene and polystyrene) on the stability of olive, sunflower and palm oils were studied at 24 and 37°C during 60 days of storage. The changes in peroxide value (PV) and thiobarbituric acid value (TBA) were significantly higher (p≤0.05) in the plastic bottles than in glass. Our study indicates that the plastic permeability has played a major role in oil stability. However, both butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) were found to leach out from plastics films into vegetable oils during storage. The rate of oxidation was not reduced by antioxidant migration from plastic films to oils. Natural antioxidant (vitamin E) retarded the oxidation rate, and this was dependent on its concentration in oils examined. The results showed that the ranking of stability of oil samples is PVC≥PET>PP≥PS. Further, the stability was dependent on the type of oil. Palm oil exibited high stability properties while the highest oxidation rate was observed in sunflower oil. In addition, increasing storage temperature accelerated the oxidation and limited the stability of vegetable oils.     

Sensory and Physical Properties of Peanut Butter Treated with Palm Oil and Hydrogenated Vegetable Oil to Prevent Oil Separation

Sensory properties of peanut butters stabilized with 0%, 1.5%, 2.0%, and 2.5% palm oil (PO) and hydrogenated vegetable oil (HVO) and stored for 153 d at 0, 21, 30, and 45 °C were determined. Oxidized flavor in unstabilized peanut butter (UPB) and PO was compared with HVO to determine shelf-life. Shelf-life of UPB stored at 21, 30, and 45 °C was 75 d. Peanut butter with 2.5% palm oil had a shelf-life of 113 d. Regression analysis indicated a linear association for the attributes graininess, hardness, oiliness, mouthdryness, and spreadability with day, treatment, and temperature. No linear relationships existed between stickiness, adhesiveness, and gumminess and day, temperature, and levels of PO.     

复配抗氧化剂对低能量类可可脂抗氧化作用的研究

采用Schaal烘箱加速氧化法,以过氧化值为评价指标,研究了二丁基羟基甲苯、植酸、维生素E三种抗氧化剂对低能量类可可脂的抗氧化效果。采用响应曲面法优化并确定了复配抗氧化剂的最优配方,结果表明：复配抗氧化剂的最优组成比例为BHT0.11‰,PA0.11‰,VE0.13‰,复配抗氧化剂各组分间具有显著的协同增效作用。通过比较最优复配抗氧化剂与单一抗氧化剂对低能量类可可脂的抗氧化效果,得出其抗氧化活性明显优于单一抗氧化剂。     

LIPID OXIDATION OF FISH LIVER OIL AS AFFECTED BY LIGHT, ANTIOXIDANTS AND TEMPERATURE

Crude and refined Mackerel liver oil with or without antioxidants were stored in artificial light or in darkness to assess the effects of photo-oxidative stress on the stability of oils and the antioxidant activity of butylated hydroxy-anisole (BHA) and tert-butylhydroquinone (TBHQ) on those oils. Changes in peroxide value (PV) and thiobarbituric acid value (TBA) were monitored over 18 days at 5C and 40C. The results showed that visible light exposure played the most critical role in the acceleration of fish liver oil oxidation. The addition of antioxidants showed a significant effect in retarding oxidation with TBHQ more effective than BHA. The oxidation rate of the oils decreased in the following order: control with light > control + BHA with light > control without light > control + TBHQ with light > control + BHA without light > control + TBHQ without light. Higher PV and TBA values were observed in refined oils versus crude oils. Increasing storage temperature accelerated the oxidation of only refined oils in light.     

Chemical composition,antioxidant and antibacterial activities of the essential oils isolated from Tunisian Thymus capitatus Hoff. et Link.

The chemical composition, antioxidant and antibacterial activities of essential oils isolated by hydrodistillation from the aerial parts of Tunisian Thymus capitatus Hoff. et Link. during the different phases of the plant development, and from different locations, were evaluated. The chemical composition was analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). The main components of the essential oils were carvacrol (62–83%), p-cymene (5–17%), γ-terpinene (2–14%) and β-caryophyllene (1–4%). The antioxidant activity of the oils (100–1000 mg l⁻¹) was assessed by measurement of metal chelating activity, the reductive potential, the free radical scavenging (DPPH) and by the TBARS assay. The antioxidant activity was compared with that of synthetic antioxidants: butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). Both the essential oils and BHA and BHT showed no metal chelating activity. Although with the other methodologies, there was a general increase in the antioxidant activity, with increasing oil concentration, maxima being obtained in the range of 500 and 1000 mg l⁻¹ for flowering and post-flowering phase oils. Major differences were obtained according to the methodology of antioxidant capacity evaluation. Antibacterial ability of Th. capitatus essential oils was tested by disc agar diffusion against Bacillus cereus, Salmonella sp., Listeria innocua, four different strains of Staphylococus aureus (C15, ATCC25923, CFSA-2) and a multi-resistant form of S. aureus (MRSA-2). Antibacterial properties were compared to synthetic antibiotics. Higher antibacterial activity was observed with the flowering and the post-flowering phase essential oils.     

THE EFFECT OF ANTIOXIDANTS ON THE KEEPING QUALITY OF SPRAY-DRIED WHOLE MILK POWDER

Spray-dried whole milk powders containing either 0.01 per cent ascorbyl palmitate or this compound plus 0.01 per cent citric acid were prepared and their keeping quality under accelerated storage conditions at 37°C compared with control powders and powders containing dodecyl gallate. Ascorbyl palmitate alone afforded little protection against oxidative deterioration but together with citric acid considerably improved keeping quality. Although the addition of several antioxidants to edible oils and fats and butter intended for manufacture is permitted, their addition to milk powder is forbidden (Regulations, 1966). There are several reasons for this discrimination, the chief of which lies in the phenolic nature of the most effective antioxidants in spray-dried whole milk powder (Findlay, Smith & Lea, 1945). More recently ascorbyl palmitate has been used to delay the onset of oxidation in butter (Koops, 1964) and milk fat (Englelhardt & de Man, 1963). It seemed appropriate therefore, despite the different chemical composition and physical condition of the fat in butter and in milk powder, to examine its effectiveness in the latter product. In the quantity employed (0–01 per cent), ascorbyl palmitate would not present a risk to health, and its usefulness could probably be enhanced by the addition of a simple synergist such as citric acid, known to be effective with dodecyl gallate in lard (Lea, 1958).     

Determination and confirmation of five phenolic antioxidants in foods by LC/MS and GC/MS

Identification and determination of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), nordihydroguaiaretic acid (NDGA), propyl gallate (PG) and tert-butylhydroquinone (TBHQ) by means of LC/MS and GC/MS were examined. These five phenolic antioxidants were detected as their pseudo-molecular ions [M-H]- by LC/MS using a Shim-pack FC-ODS column with drying gas. Moreover, BHA, BHT and TBHQ were detected based on their mass fragment ions by GC/MS. Decomposition of TBHQ, NDGA and PG during analysis could be prevented by the addition of L-ascorbic acid (AsA) to the extraction solvent. All five antioxidants were extracted from nikuman, olive oils, peanut butter, pasta sauce and chewing gum with a mixture of acetonitrile-2-propanol-ethanol (2:1:1) containing 0.1% AsA (AsA mixture), which had been cooled in a freezer and filtered. One part filtrate and 5 parts water were mixed and placed on a Mega-Bond Elut C18 cartridge, except in the case of chewing gum. Lipids in foods were removed on a C18 cartridge by washing with 5 mL of 5% acetic acid, and antioxidants were eluted with 5 mL of AsA mixture. The antioxidants spiked into nikuman, olive oil, peanut butter, pasta sauce and chewing gum were successfully identified and their concentrations determined by LC/MS, and GC/MS with good recoveries.