EFFECT OF VARIETY AND PROCESSING METHODS ON NUTRITIONAL COMPOSITIONS AND FUNCTIONAL PROPERTIES OF AWASH-1 AND CHERCHER HARICOT BEANS (Phaseolus Vulgaris L.)

Abstract

The study was conducted to determine the effects of various processing methods such as soaking, de-hulling, germination and autoclaving on proximate composition, selected (minerals and functional properties) and selected anti-nutritional factor contents of two white haricot bean (Phaseolus vulgaris L.) varieties, Awash-1 and Chercher. Datas were analyzed by SAS statistical software package (9.1.3). Mean moisture, crude protein, total ash, crude fat, crude fiber, utilizable carbohydrate and gross energy contents were 7.58, 29.40, 4.14, 2.16, 4.56, 52.15% and 345.64 kcal/100 for raw Awash-1 and 7.60, 30.44, 2.46, 3.35, 51.77 % and 351.05 kcal/100g for Chercher variety, respectively. The mineral composition of the two cultivars was also investigated. Accordingly, Awash-1 had 296.74, 23.81 and 5.75 mg/100 g contents of Ca, Fe and Zn, respectively. The values of the same types of minerals for Chercher variety were 292.98, 26.93 and 6.06 mg/100 g, respectively. From the anti-nutritional factors analyzed, the level of condensed tannin and phytic acid were 226.54 and 310.48 mg/100g, respectively, for raw Awash-1 and 241.06 and 318.13 mg/100g for raw Chercher variety, respectively. The functional properties of the two varieties were also investigated. The bulk density, water absorption index, water solubility index, swelling index, water absorption capacity and oil absorption capacity of the two varieties were 0.68 g/ml, 4.12, 1.75, 1.05%, 2.55 and 1.91 g/g, respectively, for Awash-1 and 0.67 g/ml, 4.19, 1.70, 1.04ml/ml, 2.64 and 2.06 g/g, respectively for Chercher variety. Processing methods have shown both increasing and decreasing effects on the various chemical and nutritional compositions of the beans. Autoclaving reduced the moisture content to (6.92%), total ash to (4.00%), utilizable CHO content to (50.61%), condensed tannin to (170.44 mg/100g), phytic acid content to (2570.46) and the water solubility index of white haricot bean varieties. On the other case autoclaving maximized the crude fat content to (2.90%), crude fiber content to (6.04%), bulk density to (0.701g/ml), water absorption index to (4.31%) and the water absorption capacity to (2.93 g/g) of the bean flour samples. Beans treated by soaking, de-hulling and germination had also a significant influence on the proximate compositions, minerals, anti-nutritional factors and functional properties of white haricot beans. Soaking significantly (P<0.05) reduces the iron (22.46 mg/100g) and zinc (5.20 mg/100g) contents of the treated beans where as de-hulling reduced the mean calcium content (257.50 mg/100g), crude fiber (1.48%), water absorption index (4.03%) and water absorption capacity (2.22 g/g). De-hulling maximized the crude protein (30.83%), utilizable CHO (53.86 %), gross energy content (358.65 kcal/100g), water solubility index (1.86%) and swelling index (1.17ml/ml) of samples. Moreover, germination increased the oil absorption capacity to (2.09 g/g) and reduced the condensed tannin to (199.92 mg/100g) and phytic acid content to (280.43 mg/100g). Generally, Chercher variety has high protein and energy content than Awassh-1 and autoclaving and germination processes are more effective methods to reduce anti-nutritional factors.