Study About Isolating Protein And Oil From Hazelnut Kernel By Reverse Micelles Extraction

Hazelnuts are rich in fat and protein. In the reverse micelle system, organic phase can dissolve oils, the polar cores which are contained by the surfactants are able to attract and protect polar substances, like protein. This kind of reaction is simple, cheap and continuous which means future of large-scale production; temperate conditions will not cause inactivation seriously; the solution system can be recycled to protect the environment. The reverse micellar system of sodium bis (2-ethylhexyl) sodium sulfosuccinate (AOT)/isooctane was used for the extraction of protein and oil from hazelnut kernel powder. In this paper, our main tasks were to optimize the process of extraction, form kinetic equation of forward extraction and study the structure and characters of hazelnut kernel protein isolated by reversed micelle solution system. The main conclusions are as following:1. The effects of various process parameters such as the amount of hazelnut kernel pwder, temperature, concentration of AOT, Wo, time, pH and ionic strength of the initial aqueous phase on forward process, while in the backward process we cares about the effects of last three factors, had been studied in detail. The best choice of forward process parameters were extraction temperature 37℃, hazelnut kernel powder amount 0.06g/mL, extraction time 60min, AOT concentration 150mmol/mL, Wo=27, pH=6, KCl concentration 100mmol/L. The ratio of translocation of protein and oil was 52.56±0.91% and 83.16±0.79%. According to 25min, pH 7,500mmol/L KCl solution we could obtain protein in the propotion of 74.5±1.53%.2. The forward extraction of hazelnut kernel protein, by reverse micelles, is a process of translocation from solid to liquid. This metastasis is not connected with catalytic process and appropriate with modle which has a core of non-reaction. We regard internal diffusion as the leading role of extraction, after verifying the relationships among oscillation rate, sieve mesh of powder and efficiency of forward extraction. The process may be controlled by internal diffusion, by investigating the effects of stirring indensity and particle size. After plugging the data into the model, we get an equation,2.35exp (-2010/T) t=1+2 (1-x)-3 (1-x) 2/3,which is belonging to the forward extraction of hazelnut kernel protein.3. With utilizing SDS-PAGE cataphoresis, we analyzed the components of hazelnut protein isolated by reversed micelle solution. The results revealed that the relative molecular weight distribution of the components of hazelnut protein isolated by reversed micelle solution were mainly concentrated in the range nearby 71.21KDa, 53.56KDa and 16KDa, while the relative molecular weight distribution of the components of hazelnut protein isolated by alkali-extraction and acid-precipitation method were mainly concentrated in the range nearby 132.21 KDa,65.24 KDa and 50 KDa. In the band of hazelnut protein isolated by reversed micelle solution, the propotion of protein subunits with relative molecular masses nearby 71.21KDa, 53.56KDa and 16KDa, were 30.09%、24.19% and 20.63%. No protein subunits had the relative molecular masses more than 75KDa. In the band of hazelnut protein isolated by alkali-extraction and acid-precipitation method, the propotion of protein subunits with relative molecular masses nearby 132.21KDa,65.24KDa and 50KDa, were 19.55%%、28.77% and 28.94%. No protein subunits had the relative molecular masses less than 16KDa. Compared these two kinds of proteins, we had kown that hazelnut proteins isolated by reversed micelle solution belonged to small proteins mostly.4. The structures of two kinds of protein were analyzed by FTIR. The proportion of the·second structures in hazelnut kernel protein isolated by alkali-extraction and acid-precipitation were 19.92% α-helix,33.58% β-sheet,26.44% β-turn,20.05% coil, while the hazelnut protein isolated by reversed micelle solution has 28.72% α-helix, 35.75% β-sheet,35.54% β-turn and no coil. Compared with reversed micelle method, the hazelnut protein that isolated by alkali-extraction and acid-precipitation had more kinds of the second structure. Through the spectrum, it was found that the number of infrared absorption peak of hazelnut kernel protein isolated by alkali-extraction and acid-precipitation was 9, while the number of the infrared absorption peak of hazelnut protein isolated by reversed micelle solution was 13; these two kinds of protein were different obviously. The structure of hazelnut kernel protein isolated by alkali-extr-action and acid-precipitation was affected by acid and alkali environment in a deeper degree, while the method of reversed micelle could remain chemical bonds and structure of protein better.5. Hazelnut protein isolated by reverse micelle solution had been copmpared with hazelnut protein isolated by alkali-extraction and acid-precipitation about their functionalities. It turned out that proteins isolated by reverse micelle were superior to the traditional preparation methods’ in functionalities except the oil-absorption.