3.2.4. Alpha-glucosidase inhibition
Figure 8A illustrates α- glucosidase inhibitory effects of 3% husk-emulsion with inulin addition (0, 5, 10, 15 and 20% w/w) at 5 mg/ml. All emulsion gel samples delayed α-glucosidase activity, however inhibitory activity decreased slightly with increasing inulin concentration from 0% to 20%. The husk-emulsion gel without inulin had the highest α-glucosidase inhibition (12.93 ± 0.19%), while the husk-emulsion gel with 20% w/w inulin addition had the lowest glucosidase inhibition of (10.6 ± 0.91%).
(Place for figure 7)
Fig. 8. Inhibitory potency of (A) 3% psyllium husk emulsion in the presence of different concentration of inulin at 200X dilution, and (B) puree samples with incorporated 5% or 10% husk-20% inulin emulsion gel against α-glucosidase (1 U/mL) activity at 1mM PNPG concentration. Different letters represent significant different at p<0.05.
All puree samples delayed α-glucosidase activity (Fig. 8B). The inhibitory activity of puree samples with 10% w/w replacement of the emulsion gel was higher than that with 5% w/w replacement. The results suggest that emulsion addition improved α- glucosidase inhibitory activity of the puree samples. Among the purees with 10% w/w replacement with husk-20% inulin emulsion gel, salmon had the highest glucosidase inhibition (4.54%), followed by beef and chicken (4.08 and 3.87%, respectively). The chicken stew had the lowest glucosidase inhibition of 2.13%. Previous study also suggested psyllium mucilage could delay α-glucosidase activity and entrap glucose in vitroand in vivo (Palanuvej, 2009; Gibb et al., 2015), but this mechanism has not been explored. Overall, it can be concluded that husk-20% inulin emulsion gel incorporation in food product will beneficially delay α- glucosidase activity.