Abstract:

Dietary fiber (DF) contents of faba bean testa from 20 different cultivars were determined and DF was extracted
by an enzyme-alkali method. The optimization of extraction conditions was investigated using single factor experiments
and orthogonal array design. For this purpose, the effects of four crucial parameters including cellulose dosage, pH, alkali
treatment time and temperature, on extraction efficiency were examined. Physicochemical characteristics of DF from
different faba bean cultivars were compared and analyzed. The results indicated that the DF contents of faba bean testa from 20
different cultivars were 78.7–87.12 g/100 g and the optimum extraction conditions were as follows: cellulose dosage, 30 U/g; pH,
12.0; and alkali treatment for 60 min at 60 ℃. Further, it was found that DF from the ‘Lincan 6’ had the highest water holding
capacity (7.67 g/g), the best Fe3+ and Cu2+ chelating ability (140.09 mg/g and 33.63 mg/g), whereas DF from ‘Fengdou 16’ had
the lowest bulk density (0.206 g/cm3), the largest swelling capacity (4.00 mL/g), the highest adsorption ability for unsaturated and
saturated fatty acids (4.48 g/g and 4.23 g/g), and the highest DPPH-scavenging ability (13.23 μmol/g).

Key words: faba bean testa, enzyme-alkali method, dietary fiber, physicochemical characteristics