Effect of Processing an Phytochemicals and Nutrients Composition of Fenugreek (Trigonella Foenum-Graecum L.), and Development of Value Added Products
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Date
2012-10
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Addis Ababa University
Abstract
The primary purpose of this research was to study the effects of germination, fermentation, autoclaving, extraction and their combinations on the phytochemicals and nutrients composition of fenugreek seed varieties (Challa, Ada’a and Wello). The chemical compositions, physico-chemical and functional properties, mineral bioavailability, and phytate and non phytate phosphorus contents of fenugreek seeds were investigated. Furthermore, during polar solvent extraction process, the influences of rinsing stages, solvent type, and proportion of solvent to water on the rate of extraction were also examined. The average mean value on dry weight basis of fenugreek’s moisture content was 7.5%, crude protein 29.3%, crude fat 7.9%, crude, fiber 7%, total ash 3% and total carbohydrates 45.2%. The major mineral constituents of fenugreek seeds were K (10351.7 mg/kg), P (5651.3 mg/kg), Mg (1257.3 mg/kg) and Na (121.5 mg/kg), Ca (553.7 mg/kg), Fe (81.3 mg/kg) and Zn (43.4 mg/kg). Saponins, phytates and tannins concentrations ranged from 4581.3 to 6320.8, 76.11to 111.08 and 235.24 to 269.13mg/100g; respectively. Water and oil absorption capacities were 7.5, 10.2 & 7.2 g/g of water and 1.04, 1.12 & 2.3g/g of oil absorption capacity for Challa, Ada’a and Wello; respectively. Crude protein, fat, fiber, mineral bioavailability and non phytate phosphorus compositions were improved during processing methods. Significant reduction of phytochemicals was achieved by employing conventional, heat and chemical processing methods. Germination reduced phytates, tannins, and saponins by 47.9 – 66.4%, 33.7 – 56.8%, & 46.3 – 69.9%, fermentation 68.7 – 100%, 40.7 – 87.9% & 67.8 – 81.0%, autoclaving 32.5 – 36.4%, 66.4 – 74.7%, & 88.6 – 94.6% and extraction 6.7 – 7%, 100%, & 100%; respectively. Extraction was less effective in reducing phytates as compared to other processing methods due to insolubility of phytates in alcohol (ethanol &methanol). The combination of germination and fermentation resulted in a significant and successive reduction in phytates, tannins and saponins levels. However, complete removal of all phytochemicals was achieved by the combination of fermentation followed by extraction process. During extraction, as the proportion of water increases the percolation rate decreases due to water binding property of fenugreek. Methanol extraction was faster and powerful than ethanol extraction. The extraction process also removed the astringent smell and bitterness of fenugreek. Thus, debitterized fenugreek powder was produced. In addition, to preserve the health benefits and to maintain dose of fenugreek required for different age groups, sex and health conditions, fenugreek capsules were also produced.
Key words: Chemical composition, extraction rate, Fenugreek, phytochemical, processing methods, solvent
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Keywords
Chemical composition, Extraction rate, Fenugreek, Pytochemical, Processing methods, Solvent