超细化豆渣作为皮克林乳液稳定剂的特性研究

将普通粉碎豆渣进行湿法超细化处理,研究超细化豆渣作为皮克林乳液稳定剂的特性,考察颗粒浓度、油相体积分数、pH及离子强度对乳液液滴尺寸、稳定性和流变学性质的影响。研究发现,超细化提升了豆渣颗粒的悬浮稳定性,且当油相分数φ=0.6,水相中豆渣颗粒质量分数≥0.4%时,形成皮克林乳液的粒径为80~140μm,在1~30 d存放期内乳析指数未发生显著变化。水相pH=7时乳液的粒径最大,pH降低时乳液的平均粒径呈单调递减,且乳液稳定性增强。水相中NaCl浓度在100~350 mmol/L对乳液粒径无显著影响。研究还表明,超细化豆渣稳定的皮克林乳液为剪切变稀型流体,其流变学特性受颗粒添加量及水相pH的影响。此研究表明,超细化豆渣具有良好稳定O/W型皮克林乳液的能力。

Preparation of ultrafine okara and its characteristics as a stabilizer for Pickering emulsion

The conventional pulverized okara powders were subjected to a wet-mill process to obtain ultrafine particulates.Pickering emulsion-stabilizing properties of ultrafine okara have been investigated in systems containing purified corn oil and aqueous solution at varying concentration of okara particulates,pH and ionic strengths.The effect of oil phase volume fraction,pH and sodium chloride concentration on the droplet size,stability and rheological properties of the obtained emulsion were evaluated.The results manifested that ultrafine grinding improved the suspension stability of okara particulates.Pickering emulsions with the mean droplet size of 80-140μm were made when the oil phase volume fractionφ=0.6 and the mass percentage of ultrafine okara in aqueous phase≥0.4%,and the creaming index of the emulsion did not change significantly during the storage period of 1-30 d.The droplet size of emulsion was the largest when the pH of aqueous phase was 7.However,the droplet size decreased monotonically as the pH value decreased and the stability of emulsion was enhanced in more acidic conditions.Sodium chloride concentration in aqueous phase in the range of 100-350 mmol/L has no significant effect on the mean droplet size of the emulsion.The results also showed that the okara ultra-fine particulate-stabilized Pickering emulsion possessed shear-thinning character.Its rheological properties were affected by the mass percentage of ultrafine okara in aqueous phase and the pH values.Our outcomes indicated the great potential of ultrafine okara as a natural food particle to stabilize oil-in-water Pickering emulsions.