Effects of Traditional Food Processing Methods on Nutrient Compositions and Anti-Nutritional Factors of Grass Pea (Lathyrus Sativus L.) Foods Consumed, in Ethiopia

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Addis Ababa University


The study was conducted to determine the effects of various traditional processing methods such as roasting, boiling, preparing unleavened bread (kitta) and sauce (shiro wott) on nutrient composition, and the level of anti-nutritional factors of grass pea (Lathyrus sativus). Mean moisture, crude fiber, crude protein, crude fat, total ash and crude carbohydrate contents of raw grass pea were 8.26, 8.57, 22.81, 0.61, 2.75 and 65.26%, respectively. The changes in moisture, crude protein, crude fat, total ash and crude carbohydrate contents were found to be significant for the processing methods. There were 9.47 % and 10.39% increased in protein content of roasted and boiled while there were 6.22 % and 8.46 % of lowered value of crude protein in unleavened bread and sauce. The increase in fat content of roasted, boiled and unleavened samples was found to be significant but not sauce samples. Roasted, boiled and sauce samples were decreased in ash content by 8.36 %, 16.36% and 16 %, respectively. The Ca contents increased in boiled and roasted samples. 38.45 % and 14.34 % of calcium content were decreased in unleavened bread and sauce. The P and Zn contents of grass pea samples almost in all processing methods showed significant difference. There was no a significant difference (P<0.05) in the iron content due to roasting, boiling and sauce making In unleavened bread and roasted samples, the Fe and Zn contents were increased. The results indicated that the processing methods had considerable effect on the nutrient composition and mineral contents. The raw grass pea seeds contained considerable amounts of phytic acid, (579.76 mg/100 g), tannin (352.04mg/100g and -ODAP (421.18mg/100g). These were reduced significantly (P<0.05) due to the traditional processing methods. The phytate viii content was decreased by 33.21 %, 29.76 %, 70.98 % and 74.32 % respectively in roasted, boiled, unleavened bread and sauce samples. Tannin content was also decreased by 54.06 %, 33.21 %, 91.67 % and 83.11 % in roasted, boiled, unleavened bread and sauce samples respectively. Similarly, the content of -ODAP was reduced by 12.03 %, 38.27 % and 47.22 % after roasting, boiling and preparing sauce respectively. 52% of the total phosphorus was present as phytate phosphorus in the unprocessed grass pea seeds. The traditional processing methods resulted in a significant decrease in phytate phosphorus with a corresponding marked increase in non-phytate phosphorus. Preparing sauce was found to be the best processing method, followed by unleavened bread, boiling and roasting seeds for reducing the content of phytate phosphorus. The processing method decreased the phytate: iron and phytate: zinc molar ratio and increased the calcium: phytate molar ratio. Boiling and preparing sauce (shiro wott) of grass pea were found to be the best cooking methods for healthy eating. Key words: Grass pea, nutrient composition, anti-nutritional factors, phytate, tannin, ODAP, traditional food processing methods



Grass Pea, Nutrient Composition, Anti-Nutritional Factors, Phytate, Tannin, ODAP, Traditional Food Processing Methods