Studies on retention of beta-carotene extracted from amaranthus species preserved in virgin coconut oil and unadulterated honey
Mungai, Zipporah Murugi
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Dark green leafy vegetables (DGLV) such as Amaranthus spp are known to be good sources of beta-carotene, a pro-vitamin A carotenoid and a highly potent anti-oxidant. Anti-oxidants terminate chain reactions, prevent recurrence and also prevent the formation of unstable oxygen which otherwise can initiates a chain reaction that propagates to cancerous cell. Cancer is strongly attributed to poor diet as well as lack of exercise. New cancer cases are diagnosed daily, leading to a projection of 22.2 million cases by 2030, with death tolls of up to 13.2 million. This has a huge economic burden especially to developing countries. As expected of all carotenoids, beta-carotene is highly degraded in the presence of light, heat and oxygen. Methods of its preservation are a current challenge. Preservation of powdered beta-carotene encapsulated in phospholipids, refrigerated in vacuum for a hundred days preserve 90 % of beta-carotene. Vacuum conditions require expensive instruments hence a need to explore locally available options to reduce and eradicate the menace. Moreover use of steel wool as an oxygen absorber can preserve up to 60 % beta-carotene from solar dried vegetables, however sanitation and health risk are issues of great concern. This calls for alternative methods that would ensure availability and stability of beta-carotene. In light of this, the study investigated the retention of beta-carotene extracted from Amaranthus spp bought from Githurai market (Nairobi county) and separately preserved in virgin coconut oil (VCO) extracted from coconut fruits bought from Kongowea market (Mombasa county) and unadulterated honey obtained from a farmer in Eldama Ravine (Koibatek county) as matrices for preservation. The antioxidant activity of the preservatives was determined using 2,2-diphenyl-1-picryl-hydrazyl (DPPH) assay method while, reversed phase HPLC was employed for beta-carotene analysis. Monitoring of beta-carotene was done at an interval of two weeks during the first month, followed by four weeks interval up to the sixth month. One way ANOVA was used for data analysis, with separation of mean using SNK. Coconut oil and honey gave anti-oxidant activities with % Radical Scavenging Activity (%RSA) of 65.12±0.70 and 81.51±1.39 (p<0.001) respectively. The concenteration of beta-carotene preserved in coconut oil and honey was 2.80±0.01 mg/100g (9.23 %) and 5.16±0.01 mg/100g (17.19 %) (p<0.001) respectively. Although there was over 80 % beta-carotene degradation the concentration of retained beta-carotene was 0.216±0.001 and 0.302±0.003 retinol activity equivalent (RAE) value higher than the recomended daily allowance (RDA). The RDA is 400 μg (4.0 × 10-4mg) for infant while adult require 1,300 μg (1.3 × 10-3mg ). It is envisaged that data obtained from this study will be used a stepping stone on the improvement that can be done on the preservatives, hence provide basis for development of a local and cheaper method of beta-carotene availability and preservation hence contribute to reducing cancer cases in the world by availing the much needed anti-oxidants.