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Effects of Selected Synthetic and Natural Antioxidants on the Oxidative Stability of Shea Butter (Vitellaria paradoxa subsp. paradoxa)
Abstract and Figures
Shea butter is a plant fat extracted from
kernels of shea nuts, the seeds of shea trees (Vitellaria
paradoxa). The extracted fat, which has a long
history of use in sub-Saharan Africa for medicinal,
culinary, and other applications, serves as cocoa
butter equivalents (CBEs) in the manufacture of
chocolate and is an ingredient for cosmetics in the
international market. Since shea butter contains
relatively high levels of unsaturated fatty acids (more
than 50 %), oxidation can occur during extraction and
during post-harvest processing and storage. This
study investigated the protective effects of synthetic
butylated hydroxytoluene (BHT) and selected natural
antioxidants (rosmarinic acid and gallic acid) on shea
butter against oxidation. Each antioxidant (0.02%)
was added to shea butter and the mixtures were
placed at 90°C for 0, 72, and 144 h to accelerate
oxidation. Measures of oxidation indicated the shea
butter was protected from oxidation by addition of
the antioxidants. The addition of antioxidants to
shea butter produced no significant changes in the
parameters used to measure oxidation (e.g. peroxide
values, conjugated dienes and TBARS), as well as in
the levels of major fatty acids. The natural
antioxidants were almost as effective as the synthetic
antioxidant.
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... It is the source of shea seed from which the wellknown shea butter is derived. Shea tree can be found growing in savannah belt region in countries including Senegal, Mali, Côte d'Ivoire, Burkina Faso, Togo, Ghana, Benin, Nigeria, Niger, Cameroon, Uganda, Sudan and Ethiopia [5]. The shea seed is a hard brown shell that contains the fatty kernel. ...
Vitellaria paraodoxa (shea tree) is the source of shea seed from which the well-known shea butter is derived. The methanol extract of shea seed was evaluated for its anti-inflammatory and antioxidant activities using diclofenac sodium and ascorbic acid as standard respectively in in vitro methods. The anti-inflammatory activity was determined by inhibition of protein denaturation of bovine serum albumin (BSA) and erythrocyte membrane stabilization of human red blood cell. The antioxidant activity was evaluated using 1, 1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), thiobarbituric acid reactive substances (TBARS) and total antioxidant capacity (TAC) assays. The results showed that methanol extract of V. paradoxa seed at different concentration protects the heat induced protein denaturation with the maximum percentage inhibition of 27% (IC50=303.0 µg/mL, p<0.05) at 500µg/mL compared to the standard drug which induced maximum inhibition of 45% (IC50=261.4 µg/mL, p<0.05) at 500 µg/mL and the control. The percentage inhibition of the methanol extract and standard drug in erythrocyte stabilization assay increased in a concentration dependent manner with maximum inhibitory activity of 96.9% (IC50=31.47 µg/mL, p<0.05) and 95% (IC50=33.89 µg/mL, p<0.05) at 2000 µg/ml respectively, which indicates that methanol extract stabilized erythrocyte membrane against hypotonic induced hemolysis in a blood sample better than the standard drug. The maximum percentage inhibition of methanol extract and standard drug in DPPH assay were found to be at 97% (IC50=8.95 µg/mL, p<0.05) and 98% (IC50=6.72 µg/mL, p<0.05) respectively at 100 µg/ml. The absorbance of the reductive capacities in FRAP assay indicates that the methanol extract has higher reducing potency in a concentration dependent manner. The methanol extract exhibited total antioxidant capacity of 0.25 ± 0.04 µg/(AAE/g) when compared to the standard drug 0.87 ± 0.03 µg/(AAE/g) at highest concentration of 100 µg/ml. For TBARS assay, low absorbance value indicate a high level of inhibition of lipid peroxidation. The maximum percentage inhibition of methanol extract was 97.5 % (IC50=51.79 µg/mL, p<0.05) and ascorbic acid was 99% (IC50=52.30 µg/mL, p<0.05) at concentration of 20 µg/ml. The assay indicates that the methanol extract has higher inhibiting potency in a reverse concentration dependent manner. In conclusion, V. paradoxa seed may possess strong anti-inflammatory and antioxidant activities which could constitute a potential source for development of new therapy.
ABSTRACT
The protective effect of added rosemary extract (RE) on the oxidative stability of highly unsaturated Camelina sativa oil was followed by periodic determination of its peroxide value (PV) during storage in darkness at room temperature. In camelina oil containing RE, a peroxide value of 10 mmol O2 / kg, the upper limit for unrefined oils, was not attained after 11 months’ storage. Compared to unprotected camelina oil the formation of hydroperoxides in oil containing RE was reduced by more than 40 %. The effect of RE against oxidation of camelina oil was also measured by the Rancimat test. In fresh camelina oil treated with RE the induction period was extended by 60 % as compared to untreated oil. Also, RE was more effective in preventing oil from oxidation when the oil was stored in darkness than in daylight.
Shea butter from the Shea tree (Vitellaria paradoxa C.F. Gaertn.) is an important plant fat rapidly gaining popularity in cosmetics, personal care products and foods. Shea butter is becoming more popular because of its unsaturated fatty acids composition as well as the potential utility of its unsaponifiables fraction now being used in cosmeceutical, pharmaceutical and nutraceutical applications. The chemical constituents, physical and chemical properties, quality impacting factors, quality control issues, as well as the current and potential new uses of Shea butter by different industries are reviewed.
The objective of this study was to determine the effect on fatty acid composition of heating olive and sunflower oils with selected natural and synthetic antioxidants. The antioxidants investigated were quercetin, caffeic acid, protocatechuic acid, and butylated hydroxyanisole (BHA), each at concentrations of 0.02, 0.04, and 0.06%. Oils with no added an-tioxidants were also heated. After heating of the samples at 90°C for 72 h and 120 h, then preliminary saponification of the fat and esterification of the acids, the fatty acids were determined as the methyl esters by gas chro-matography; heptadecanoic acid was used as internal standard. The high temperatures had a negative effect on fatty acid composition. Olive oil was more resistant than sunflower oil to changes during heating. In general, the effectiveness of natural antioxidants (quercetin, caffeic acid, and protoca-techuic acid) was no less than that of the synthetic antioxidant (BHA).
Dry extraction of shea (Vitellaria paradoxa) butter from shea kernel was carried out in an instrumented mechanical expression rig. Shea butter was expressed at a pressure of 8.8 MPa applied at the rate of 2.5 mm/min on crushed shea kernel heated at 50, 70, 90 and 110 degrees C. The characteristics investigated on shea butter were specific gravity, refractive index, moisture content, melting point, viscosity, colour intensity, saponification value, iodine value, free fatty acid value, ester value, total acid value, peroxide value and rancidity index. Ester values of 216.6, 211.0, 194.2 and 180.3 while iodine values of 85.4, 83.3, 81.7 and 78.8 were obtained at 50, 70, 90 and 110 degrees C, respectively and saponification values at these temperatures were 261.3, 258.1, 244.7 and 237.7 while free fatty acid values were 6.3, 7.6, 12.2 and 15.4, respectively.
Analytical information on fats and oils is required for trading, quality control, nutritional labeling and forensics. Development of analytical procedures was one of the historical reasons for the organization of the Society of Cotton Products Analysits; it continues as a major effort of the successor organization, the American Oil Chemists’ Society, through its Uniform Methods Committee and final publication of methods in the Society’s “Official and Tentative Methods.” A review of the current status of methods development will be followed by a glimpse of methodological research currently underway.
Virgin olive oil has a high resistance to oxidative deterioration due to both a triacylglycerol composition low in polyunsaturated fatty acids and a group of phenolic antioxidants composed mainly of polyphenols and tocopherols. Polyphenols are of greater importance to virgin olive oil stability as compared with other refined oils which are eliminated or drastically reduced during the refining process.This paper covers the main aspects related to the oxidative stability of virgin olive oil during storage as well as at the high temperatures of the main processes of food preparation, i.e., frying and baking. Differences between oxidation pathways at low and high temperature are explained and the general methods for the measurement of stability are commented on. The compounds contributing to the oxidative stability of virgin olive oils are defined with special emphasis on the antioxidative activity of phenolic compounds. Finally, the variables and parameters influencing the composition of virgin olive oils before, during and after extraction are discussed.