Comparison of Α-Tocopherol with Some Nigerian Spices as Natural Antioxidants in Stored Crude Groundnut Oil (Published)
The antioxidant effects of M. myristica, M. tenuifolia and A. danielli in comparison to α-tocopherol in crude groundnut oil stored at room temperature for 24 weeks were studied. Crude groundnut oil samples mixed with 200 ppm each of the grits (0.5 mm) and n-hexane extracts of the three spices were compared to two controls: untreated crude groundnut oil and crude groundnut oil mixed with 200 ppm α-tocopherol and all were stored for 24 weeks at room temperature. Samples were tested for free fatty acid and peroxide value after the fourth and eighth week of storage and afterwards, every two weeks, until the 24th week. At the 24th week, % FFA was highest (3.67 %) in untreated (control 1) samples and lowest in α –tocopherol-treated (control 2) samples. Again, peroxide value was highest (33.59 meq/kg) in untreated (control 1) samples and lowest in α-tocopherol-treated samples. Both the spice grits and their extracts significantly reduced peroxide value and % FFA better than the untreated samples, with the spice extracts performing better than their grits. The study suggests that crude groundnut oil can be stored with 200 ppm grits and n-hexane extract of the three spices and better results might be achieved at even higher concentration.
Keywords: A. danielli, Antioxidant, Groundnut-Oil, M. myristica, M. tenuifolia
Antioxidant Activity, Phytochemical and Antioxidant Levels of Musa Paradisciaca L. And Musa Sapientum L. At Various Ripening Stages (Published)
Musa paradisiaca L. (plantain) and Musa sapientum L. (banana) are tropical fruits that play a major role in the nutrition and health of people throughout the world. Analyses of the levels of antioxidants such as glutathione, caroteniods and vitamin E of two cultivars of Musa paradisaca and three cultivars of Musa sapientum revealed an increase in these antioxidants from the unripe to the overripe stage during ripening. The overripe stages of Musa paradisiaca L.cv. French (Bini plantain) and Musa sapientum L.cv. Bluggoe cacambou (Cooking banana) were found to contain the highest level of glutathione (54.10±0.60 μg/g fresh weight and 47.79±3.45 μg/g fresh weight, respectively). The highest level of lycopene occurred in the overripe stages of Musa paradisiaca L. cv. False horn (Auchi plantain) and Musa sapientum L.cv. Bluggoe cacambou (Cooking banana) with values 0.91±0.00 and 0.80±0.01 μg/gfresh weight, respectively. The highest level of vitamin E (20.20±1.99 μg/gfresh weight and 17.53±1.18 μg/gfreshweight) occurred in Musa paradisiaca L.cv False horn (Auchi plantain) and Musa sapientum L.cv Dwarf Cavendish (English banana). However β-caroetene was detected only in the unripe stage of Musa paradisiaca L.cv False horn (Auchi plantain) and the level of β-carotene was negligible. Phytochemical screening of the plantain and banana cultivars showed decreased levels of tannins, phenols and alkaloids but increased levels of saponins and flavonoids as ripening progressed except in Musa sapientum L.cv. Bluggoe cacambou (Cooking banana) where there was a decrease in the level of saponins. Antioxidant activity also increased with ripening in the plantain and banana cultivars, with their ripe and overripe stages having the highest values. Methanolic extracts of the plantain and banana cultivars showed higher antioxidant activity than that of aqueous extracts. The results obtained in this study showed that plantain and banana irrespective of the variety are good sources of antioxidants particularly when they are ripe and overripe.
Keywords: Antioxidant, Musa Paradisiaca, Musa sapientum, Phytochemical, ripening
Evaluation of antioxidant activity of ethanolic extract from irradiated sunflower (Helianthus annuus L.) seeds hull (Review Completed - Accepted)
Sunflower seeds hull are by-products of the sunflower industry that has low economic value despite its high content of antioxidants such as phenolic compounds and recently natural antioxidants have gained increased interest because natural food ingredients are safer than synthetic ones. Thus, the aim of investigation to evaluate the antioxidant efficacy of ethanolic extract of irradiated sunflower (Helianthus annuus L.) seeds hull (Sakha- 153 variety) at dose levels of 0, 3, 6 and 9 kGy on total phenolic compounds and total antioxidant activity were studied, and the composition of phenolic compounds of ethanolic extract of non-irradiated and irradiated samples was determined by HPLC. The results exhibited that the all extract of samples under investigation possesses high stronger antioxidant activity, especially samples ethanolic extracts of irradiated at dose level of 6 kGy. For further confirmation, the ethanolic extract of irradiated samples at dose level of 6 kGy was investigated on beef minced meat model system. Different concentrations of ethanolic extract of irradiated samples at dose level of 6 kGy and Tert-Butylhydroquinone (TBHQ) were added to beef minced meat and cooked at 100±2ºC for 30 min. after cooling at room temperature, the cooked samples were stored at cold storage 4±1ºC for 7 days. Thiobarbituric acid reactive substances (TBARS) values proved that ethanol extract of Sakha- 153 sunflower hulls had a power of inhibiting lipid oxidation comparable to TBHQ and exhibit antioxidant activity superior to TBHQ in the beef minced meat model system. Furthermore, the results showed that the ethanolic extract of irradiated sunflower seeds hull samples at dose level of 6 kGy were effective in inhibiting lipid oxidation of sunflower oil. Thus, these results are very beneficial for using the ethanolic extract of irradiated sunflower seeds hull samples at dose level of 6 kGy as natural stronger antioxidant and cheap price in food industry field.
Keywords: Antioxidant, Ethanolic extract, Sunflower seeds hull
Assessment of Date Kernel as Natural Antioxidant and Anti-pathogenic Bacteria Source (Review Completed - Accepted)
Date (Phoenix dactylifera L.) kernels were assessed for their chemical composition, phenolics, antioxidant capacity, inhibiting lipid peroxidation and antibacterial activity against some pathogenic Gram-positive (Listeria monocytogenes, Staph. saprophyticus) and Gram-negative bacteria (E. coli, Salmonella enteric). Kernels from four cultivars Shishi, Menaify, Barhee and Khulas were used in this study, Phenolic compounds ranged from 740 to 1200 mg/100g in Menaify and Khulas cultivars, respectively. Ethanol extract of date kernels showed high antioxidant capacity against 1, 1-diphenyl-2 picryl hydrazyl from all tested cultivars with means of 88.88% at 500ppm and strong reducing power at concentration of 200ppm. Lipid peroxidation inhibition was recorded for all tested cultivars with means of 90.2% inhibition. Ethanol extract of date kernels was effective against Listeria monocytogenes, Staph. saprophyticus, Salmonella enteric but not against E. coli. Date kernels were more effective in inhibiting growth of Staph. saprophyticus bacteria than antibiotic chloramphenicol in this study. The results revealed that date kernels extract may have a good potential role in preventing the free radical species in food systems as well as the antibacterial role against some pathogenic bacteria.
Keywords: Anti lipid peroxidation, Antibacterial, Antioxidant, Date kernels, Ethanolic extract