Production and anti-diabetic activity of soluble dietary fiber from apricot pulp by Trichoderma viride fermentation

Soluble dietary fiber (SDF) was prepared by Trichoderma viride fermentation by using apricot pulp as the raw material. A four-factor and three-level response surface methodology was applied to optimize the fermentation conditions affecting the extraction rate of SDF. The optimum fermentation conditions were listed: crude enzyme volume, 9.59 mL g(-1); fermentation temperature, 43 °C; initial pH, 5.36; fermentation time, 6.47 h. Under these conditions, 15.69% yield was obtained and its relative error with the predicted theoretical value (15.87%) was 1.14%. The dietary fiber content of SDF was 84.0% whereas it was found to be 43.1% in apricot pulp flour. The anti-diabetic effect of apricot pulp SDF on rat models of diabetes was investigated. Both the blood glucose level and body weight were significantly changed in apricot pulp SDF-treated groups compared with the diabetic group (p < 0.01) after intragastric administration for 28 days. In addition, SDF elicited inhibitory effects on the α-glucosidase activity with an IC50 of 17.458 mg mL(-1). These results implied that apricot pulp SDF relieved the symptoms of diabetic rats.