Kiwi Seed Meal And Crude Protein Processing Properties Of Cellulose Synthase Like Protein Purification And Identification

Kiwi (Actinidia chinensis Planch.) is kiwi fruit vine. This delicious and nutritious fruit is very popular with people. In recent years, the product market of kiwi fruit is more and more big. The amount of by-product, kiwi fruit seed was gradually increased. Therefore, it is particularly important to reasonably use the kiwi fruit seed. At present, the domestic and foreign scholars research mainly in the aspect of kiwi fruit seed oil and study less about kiwi fruit seed protein. Our study is based on kiwi fruit seed to carry out the extraction, processability study, isolation, purification and preliminary identification of purified protein structure of kiwi fruit seed protein. The results are as follows.First, the content of crude protein in kiwi fruit seed was16.26%by kjeldahl determination. Four kinds of kiwi fruit seed proteins were extracted using different solvents step by step. The content of alkali soluble protein was highest about5.03%of kiwi fruit seed dry weight. Water soluble protein accounted for5.00%. Salt soluble protein and alcohol soluble protein content were less.Second, the water-soluble protein of kiwi fruit seed was extracted by alkali soluble acid sinking method. Analysis showed that the water-soluble protein of kiwi fruit seed included variety of amino acids, especially eight essential amino acids. The content of glutamate was as high as23.5mg/g. The molecular weight of kiwi fruit seed protein was smaller (20KDa～66KDa) by SDS-PAGE analysis. At pH7.5, the emulsification and emulsion stability of kiwi fruit seed protein was35.33%and64.79%, respectively. It was higher than that at pH4.0. The foam capacity of kiwi fruit seed protein was34.83%at pH4.0.Third, in order to study the change of conformation and structure of kiwi fruit seed water-soluble protein at different temperatures, pH values and denaturants, we analysed the fluorescence spectrum of kiwi fruit seed water-soluble protein. We found that the emission maximum of kiwi fruit seed water-soluble protein was344nm under the condition of pH7.0,25℃. With the increase of temperature (25℃～90℃), the fluorescence intensity of kiwi fruit seed water-soluble protein gradually reduced. The influence of different pH values showed that the fluorescence intensity of protein is highest at pH7.0. Adding sodium dodecyl sulfate (SDS) caused a significant blue shift about10nm in the emission maximum of protein. The effect of SDS was mostly significant compared with dithiothreitol (DTT), urea, guanidine hydrochloride and acrylamide.Finally, we extracted kiwi fruit seed protein by the ammonium sulfate precipitation step by step and used DEAE Sepharose Fast Flow anion exchange column and Sepharose CL-6B gel filtration column to purify the kiwi fruit seed protein obtained by adding saturation of40%-80%ammonium sulfate. The purification product of kiwi fruit seed protein was obtained. Purification protein probably included two subunits (-53KDa and-65KDa) by SDS-PAGE analysis. Mass spectrometry analysis was carried out on the purification protein. We deduced that the purification product probably is similar to cellulose synthase-like protein through the analysis of Mascot database.