Abstract:

Mulberry leaf proteins were obtained via ultrasonic-assisted extraction and subsequent acid precipitation. The effects of pH, NaCl concentration, sucrose concentration and temperature on functional properties of mulberry leaf proteins were investigated. Results indicated that better solubility, water-holding capacity, emulsifying capacity and emulsion stability, foaming capacity of mulberry leaf proteins were observed at pH far away from isoelectric point (pI = 5). The water-holding capacity, solubility and foaming capacity of mulberry leaf proteins had respective positive correlation with NaCl concentration within the range of 0－1.0 mol/L. The highest emulsifying capacity was observed at 0.8 mol/L and the highest emulsion stability at 0.6 mol/L and a higher level of NaCl concentration resulted in a remarkable decline in both of them; as sucrose concentration increased, the water-holding capacity increased but the solubility and foaming capacity decreased and no pronounced changes in the emulsifying capacity and emulsion stability were observed; the oil-absorbing capacity or foaming capacity of mulberry leaf proteins were positively correlated with temperature, while the water-holding capacity, solubility, emulsifying capacity and emulsion stability of mulberry leaf proteins were the best at 60 ℃.

Key words: mulberry leaf protein, water-holding capacity, solubility, emulsifying capacity, foaming capacity