Study On Processing Technology And Its Strutural Properties Of Cold Pressed Walunt Cake

China's walnut cultivation and production are the first in the world.Apart from some fresh sales at home and abroad,it are mainly used for processing into walnut oil,walnut powder,walnut milk and other products.Walnut oil produces a lot of skim walnut cake as fertilizer or feed.There are high protein content of 40?50%in the cold?pressed walnut cake.In order to effectively use the resources of walnut protein expand its products in the field of food processing and other applications.The cold?pressed walnut cake tannin removal technology,spray drying technology walnut powder and protein extraction techniques were studied in-depth study in this article.The functional properties of walnuts isolated protein,secondary structure and molecular weight distributionwere deeply investigated..The results obtained are as follows:(1)Through the single factor experiment and response surface analysis,we find that the optimal conditions of removal rate of tannin from cold pressed degreased walnut is:Soak Temperature>material/liquid ratio>soaking time>pH;Soak Temperature 55?,pH 7,soaking time 150 min and material/liquid ratio 1:25.Repeated soak 1 times,soaking time 30 min with the first Other conditions,the removal rate of tannin was 50.44%and protein lost was 2.97%.Tannin removal rate of cold pressed degreased walnut was higher and protein loss rate was lower,Which were provided a theoretical basis for the development and utilization for high?quality cold pressed degreased walnut protein.(2)In order to make an effective use of the physical and chemical indexes and yield of walnut powder,the technology of spray drying for cold pressed degreased walnut protein was studied.With response surface analytic method,the results showed that the maximized drying efficiency obtained with processing parameters of maltodextrin adding amount 18%,??cyclodextrine adding amount 3.5%,hot air temperature 200?,Under these conditions,the spray dried powder yield efficiency was 67.56%,protein content was 83.92%.Under these conditions,has the highest sensory evaluation score,product particles moderate,high quality.it was suiTablele for industrial production(3)We find that the optimal conditions of protein extraction from tannin from cold pressed degreased walnut is:Soak Temperature 55?,pH 7,soaking time 150 min and material/liquid ratio 1:40.Under such conditions,the actual measured protein extraction from tannin of cold pressed was 89.14%.Walnut protein's solubility,water holding capacity,oil absorbency,foamability and emulsifying capacity were the best.(4)In the present paper,Fourier transform infrared spectra(FTIR)of cold pressed degreased walnut protein was measured with different pretreatment conditions.and the compositions of walnut protein ? class structure were analyzed by Fourier deconvolution,second derivative and curve fitting methods.The results showed:the presence of these proteins walnut slight spectral differences,there are also some differences between the composition of protein secondary structure.Its a-helix and nonregular coil was larger in the mass.The grinding and sieving is removal of tannin and sieving,removing tannin unscreened protein ? class structure was damage smaller,while ensuring the integrity of protein structure,we prepared protein powder for the selection of grinding and sieving better.The pretreatment methods for preparation of walnut protein subunit composition and chromatography difference in polypeptide,amino acid content decreased slightly,the other amino acid content is the walnut powder increased,which indicates that pretreatment on amino acid damage was not significant,grinding and sieving,removal of tannin and sieving,and tannin is not sieving compared,except valine,lysine and tryptophan,the other 15 kinds of amino acid content is high.Therefore,grinding and sieving protein ? class structure is well preserved,amino acid content is higher,being a better treatment method.