Abstract:

In this study, the enzymatic hydrolysis of ripen fresh mulberries with pectinase and cellulase individually and in
combination was optimized using combination of one-factor-at-a-time method and response surface methodology to obtain
maximum juice yield. Further investigations were carried out to examine the influence of microfiltration as a non-thermal
sterilization technology on microbial load, clarity, browning and physicochemical properties of the mulberry juice. A mixture
of pectinase and cellulase was the most efficient enzyme for actual production of mulberry juice and the optimal hydrolysis
parameters were determined as follows: pectinase concentration, 0.42%; cellulase concentration, 1.84%; hydrolysis time,
101.26 min; hydrolysis temperature, 50 ℃; and pH, 3.5–4 (the natural pH of mulberry juice). Experiments conducted
under the optimized conditions led to a mulberry juice yield of 86.37%, agreeing with the predicted value (88.10%).
Our study also demonstrated that microfiltration could not only reduce the microbial load of mulberry juice but also be
effective against its browning.

Key words: enzymatic hydrolysis, mulberry juice, microfiltration, response surface methodology, clarification