Abstract:
This research is aimed to transform high protein content wastewater from mungbean starch factories into value added products such as fat replacer. The feasibility of isoelectric precipitation method to separate protein from wastewater followed by freeze-drying process to produce dried mungbean protein (MBP) is reported. An exceptionally good quality MBP (protein 88.93%, ash 4.59%, fat 0.78%, carbohydrate and fiber 5.7%) is obtained from these processes. Significant characteristics of MBP are: oil adsorption at 5.76 g oil/g MBP. water adsorption at 2.41 g water/g MBP, surface hydrophobicity 30 (BSA 1000), emulsifying activity index (EAI) 83 (BSA 102), delta H of denaturation 13.53 J/g, minimum solubility at pH 4.5. It was found that denature temperature increased when protein concentration increased. Chemical modification of MBP is done via succinylation with succinic anhydride. The rate of chemical modification decreased when concentration of modifying agent increased. Maximum surface hydrophobicity of modified MBP was obtained with 0.4g succinic anhydride/g MBP. Solubility at pH 4.5 and 7.0, water adsorption and EAI of modifiec MBP are higher than those of unmodified protein significantly, while oil adsortion is not difference. Other characteristics of modified MBP are: denature temperature 83 ํC and delta H of denaturation 3.62 J/g. Optimum conditions for production of fat replacer can be obtained by directly heating unmodified MBP at 83 ํC for 15 minutes coupled with homogenizing at 17,000 rpm and continued homogenizing at 23,000 rpm for 15 minutes without heating. Then, oversized particles (>3 microns) were precipitated at 4000 x g for 10 minutes, resulting in 94.66% protein particles of 0.1-3 microns in supernatants