EFFECT OF PROCESSING METHODS ON NUTRITIONAL VALUE 0F DAB 410 AND SER 119 COMMON BEAN (PHASEOLUS VULGARIS L.) VARIETIES GROWN IN ETHIOPIA

Abstract

The common bean (Phaseolus vulgaris L.) is a staple legume meal utilized in various local dishes and as a cheap source of protein and a major source of financial income. However, the presence of certain anti-nutritional factors has become a hindrance to the availability of nutrients during consumption. It is hypothesized that some processing methods could alleviate the problem and increase the benefit obtained from legumes. The purpose of this study was to see how different processing methods affected the nutritional value and anti-nutritional factors of improved common bean varieties (Dab 410 and Ser 119) grown in Ethiopia. The experiments used a factorial design with common bean varieties as first factor of two levels (Dab 410 and Ser119) and processing methods as a second factor of five levels (roasting, soaking, dehulling, germinating and boiling). SAS version 9.1., was used to analyse the data. Standard procedures were followed for chemical and physical analyses. The moisture content, ash, crude fiber, crude protein, crude fat, carbohydrate and total energy of the raw common bean were 9.54%, 3.42%, 4.52%, 24.43%, 1.51%, 56.56% and 337.65 Kcal/100g for Dab 410 and 9.85%, 4.13%, 5.36%, 22.23%, 1.42%, 57.00% and 329.74 Kcal/100g for Ser variety. After processing, the values for these parameters were 8.97%, 3.23%, 3.79%, 24.32%, 1.54%, 57.96% and 342.69 Kcal/100g and 9.11%, 3.77%, 4.56%, 22.21%, 1.42%, 59.02% and 337.85 Kcal/100g, respectively, for Dab and Ser variety. Ca, Fe and Zn contents of raw common bean variety were 21.73, 6.85, and 2.42 mg/100g, for Dab variety and 26.06, 7.44, and 3.44 mg/100g, respectively, for Ser variety. After processing, the contents were 16.85, 5.22, and 1.88 mg/100g, respectively, for Dab variety; for Ser variety, they were 21.62, 6.50, and 2.65 mg/100g for Ca, Fe, and Zn, respectively. The anti-nutritional factors, tannin and phytic acid were 35.72 and 115.03 mg/100g in the raw Dab variety, while for Ser variety they were 40.85 and 126.65 mg/100g, respectively. After processing, these parameters were reduced to 16.43 and 85.62 mg/100g, respectively, for Dab, whereas for Ser variety, they were 18.86 and 89.94 mg/100g, respectively. The bulk density, solubility index, swelling power, water absorption capacity, and oil absorption capacity of the Dab variety were 0.55 g/mL, 26.16 %, 15.14 %, 2.84 g/g, and 1.03g/g, respectively. In comparison, they were 0.61 g/ mL, 24.62 %, 13.15%, 2.17 g/g, and 1.12 g/g, for the Ser variety, respectively. Physicochemical properties, namely, seed mass, seed density, hydration capacity, hydration indices, swelling capacity, swelling indices, and unhydrated seed of Dab and Ser common beans variety were 57.26 & 26.43 g/seed, 0.68 & 0.84 g/ mL, 0.77 & 0.63 g/seed, 0.53 & 1.24%, 0.47 & 0.36 mL/g, 1.48 & 1.24 % and 1.30 & 2.01%, respectively. The results indicated that De>Bo>Ge>So>Ro and Bo>Ge>De>So>Ro in reducing the anti-nutritional factor of tannin and phytic acid, respectively. The Dab common bean variety had low anti-nutritional contents after various processing techniques. As a result, it can be used as raw material in the food processing industry to produce quality food formulation and weaning food.