Effects of Various Processing Methods on Proximate Composition, Minerals and Beta-Carotene Content of Two Local Carrot Varieties

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Addis Ababa University


Vitamin A deficiency is a public health problem in Ethiopia. It affects vision, growth, tissue differentiation, reproduction and immune system. Carrot varieties are known to contain high amount of β-carotene which is the major precursor of Vitamin A. This study was designed to determine β-carotene and changes in nutrient composition after various methods of processing (Roasting, boiling, Roasting + boiling and powdering) on two local varieties of carrot variety. Atomic Absorption Spectroscope and colorimeter were used for the analysis of minerals and High Performance Liquid Chromatography was used for β-carotene determination. The proximate (moisture, ash, fiber, fat, carbohydrate, protein, and mineral (Zinc, Potassium, Iron, Magnesium, Phosphorus and Calcium) content in raw carrot varieties and corresponding processing methods were determined. In addition, β-carotene level was determined. The β-carotene level ranged from 8824μg/g (Chantenay) to 1933.3μg/g and 8900μg/g (Nantes) to 2466.6μg/g. There was significant difference (p <0.05) between the two varieties and among the different processes in β-carotene contents. Nantes variety found to be high in β-carotene. Moisture content, 89%-91.8%, 88.5- 90.4%, crude protein, 0.18-1.7%, 0.51%-1.53%, crude fat, 0.35%-0.54%,0.22%-0.61%, crude fiber 1.23%-1.06%,1.3%1.06%,and total ash ranged 1.9%-0.8%, 1.9%-0.8%, carbohydrate 8.01%-3.39% 8.9%-4.2% for both Chantenay and Nantes, respectively. Similarly, the range of iron, 0.34-1.29, 0.3-1.26 magnesium, 10.2-12.1, 9-11.4 potassium, 198-318, 215-352 zinc, 0.2, 0.2-0.4 calcium 30-31, 30.6-32.3 and phosphorous19.9-33, 20-33 mg/100g were for both Chantenay and Nantes respectively. Thus processing specially boiling + roasting significantly affected the Beta-carotene, protein, ash, fat and iron, magnesium content of both varieties though Nantes carrot varieties were found to be better than Chantenay in terms of retention of proximate composition, minerals and β-carotene content after the various thermal processing methods. On the other hand, powdering did not significantly affect the proximate composition, minerals and Beta-carotene content of both Chantenay and Nantes varieties. The study revealed that both Nantes and Chantenay carrot varieties can provide adequate amount of beta carotene to fulfill the daily requirements. Hence consumption of moderately processed; especially boiled and powdered carrots is preferred intervention in fighting Vitamin A deficiency. Key words: Beta-carotene; Chantenay; Nantes



Beta-carotene; Chantenay; Nantes