| Protein is the material basis of life. Amino acids, proteins’ hydrolysate, play animportant role in promoting food flavor and are widely used in food activitie industry.Moreover, the proteins’ primary hydrolysate, active peptide can not only be easilyabsorbed by human body, but also balance the body. In China, people daily proteinintake is less than that demanded by FDA, because of special diet structure. Therefore,exploring the protein and its hydrolysate extensively has positive effects on humanhealth and the social development. Conventionally, protein has been hydrolyzed byenzyme. Although enzyme has higher catalyzing effciency, it is sensitive to the slightchange of condition and not easy to be separated from resultant. Immobilized enzymecan solve the problem of subsequent recovery and recycling, but it is not capable ofovercoming the intrinsic weakness of enzyme.Fruit consists a great deal of polyphenols and protein. Polyphenols are prone tocomplex with protein in aqueous solution when fruits are used to brew juice and winewhich will lower the stability and flavor quality of juice and wine. Therefore,clarification of fruit drinks is of great importance. Traditionally, the bentonite is a kindof effective flocculant used in wine. However, the large consumption andnon-renewable property determine the high cost and energy consumption in the wineindustry. It is not common to use chemical modified chitosan resin to clarify juice andwine.In this reseach, we use chitosan, cyclen and copper chloride as primary materialsto prepare complex of modified chitosan resin with copper ions (CMCR) by reversesuspension cross-linking method with formaldehyde and epichlorohydrin as thecross-linking agent, which can be capable of hydrolyzing proteins. Moreover, westudy the effect of CMCR on the clarification of wine. Specific results are as follows:1) The apparent properties of CMCR are identified. CMCR is a mazarine sphericalmicrosphere, which possesses pile-up density and its average diameter is353μm. CMCR also has appreciated stability towards acid. The results of DSC and XRD showthat cyclen and copper ion attached to chitosan resin by coordinate bonds and that isCMCR. Furthermore, copper ions chelated on the CMCR are stable in wide pH(3.0~9.0) and temperature (20°C~60°C) range.2) CMCR is capable of hydrolyzing proteins. By using the methods such asSDS-PAGE and HPLC to detect the hydrolysis degree of myoglobin, collagen andlysozyme. The results demonstrate that at near-physiological pH, myoglobin andlysozyme can be hydrolyzed more than70%during24h, while collagen can behydrolyzed more than75%during48h. Although the reaction rate is accelerated withthe increase of temperature, the higher temperature can also aggravate the degradationof protein by itself. Therefore, it is better to keep the reaction temperature in60°C orso.3) CMCR has better clarification effect. The results demonstrate that the content ofprotein and polyphenols in wine decrease by around25%and27%respectively andthe clarity is improved more than30%with CMCR treatment. Protein in brewingwine can be degraded by CMCR while the content of amino acids increases.Therefore, CMCR can not only improve the stability of wine, but also enhance thenutritious value of wine. With the significant comprehensive benefits, CMCRdeserves widely promotion in the food industry.Protein and its hydrolysates play an important role in keeping human health andfood industry. Moreover, the traditional methods of hydrolysis of protein have a fewshortcomings. In our research, we use chitosan, cyclen and copper chloride as primarymaterials to prepare new-type chitosan derivative–complex of modified chitosanresin with copper ions (CMCR). Besides, we study the effect of CMCR on thehydrolysis of proteins and the clarification of wine. This study provides a new methodand foundamental application for the hydrolysis of protein and the clarification ofjuice and wine. |
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