Fig. 5. Potential prebiotic effect of WPI/inulin nano complex measured by the viability of L. acidophilus ATCC 43121. Time, incubation time at 37℃; Treat, addition of prebiotic substrates; ns, not significant (p<0.05); Negative control, minimum media; Positive control, minimum media containing 1% (w/v) inulin; 1% WPI, minimum media containing 1% (w/v) WPI; WPI/inulin nano complex, minimum media containing WPI/inulin nano complex (final concentration = 0.5% (w/v) WPI and 0.5% (w/v) inulin). The number of viable cells were measured by using standard plate method on MRS agar media during 48-h incubation at 37℃.