The High Efficiency Utilization Reserch In Skin,Scales,Fishtail Of Tilapia

The output of Oreochromis niloticus occupies first place in freshwater fish. During processing sliced tilapia, great quantities of the byproduct such as scraps-head, scales,fishtail skill are produced. Among these wastes, most is scales,fishtail, skill. Therefore, this thesis studies, used hainan tilapia fish scales,fishtail, skill, with different methods, studied the high efficiency utilization ways of fish scales, fish tail, fish skin, so as to enrich the application area of fish scales, fishtail, fish skin, provided the basis of theory for developing high value-added products.And the definite work was as follows:1Tilapia skin raw material characteristics and collagen extractionThis thesis studies on isolation collagens from the skin of tilapia. The results indicate that the crude protein and collagen content ofthe skin of filapia which is obtained from fish-processing factory are up to32.68%and26.91%. respectively,on the basis of wet weight. The content of collagen account about82.31%of the crude protein. The acid solution collagen is rish in glycine35.79%. The amounts of imino acids, proline and hydroxyproline in acid solution collagen is25.48andl5.20residues per1000residues. Respectively.The distinct absorption are obtained at232nm; respectively. This result is in accordance with the characterization of the type I2Investigation on fish pigment separation methods and its antioxydative activity from tilapia skinThe ability of scavenging free DPPH radical was used to study the extraction technology of antioxidant components of tilapia skin pigment, discussed the separate purification of extract and the ability of antioxidant. Consequently, it was found that the highest extraction rate of skin pigment and scavenging rate of DPPH free radical were predominant produced on the treatment with citric acid after extracting in the methanol solution. In the resin adsorption process, the adsorption equilibrium achieved within40min and the adsorption efficiency decreased with the increase of sample concentration. Followed by eluting the adsorbed resin with acetone, the best desorption efficiency of skin pigment in comparison with the total practical samples was obtained. The desorption equilibrium achieved within20min.Eluting liquid ratio of1:2had the best effect. Adsorption efficiency could reach more than85%at a sample flow rate of0.10-0.20mL/min. Desorption efficiency could achieved within90%at desorption rate0.15-0.40mL/min, the ability of DPPH radical scavenging activity increased obviously. It can be expected for practical use to separate and purify of natural anti-oxidation component in fish skin pigment because X-5resin mentioned above had strong adsorption and separation capacity for pigment active constituent.3Influence of different crosslinking on physicochemical properties of collagenIn order to improve the collagen of the physicachemical properties, using1-ethyl-3-(3-2dimethyl amoniapropyl)-carbonization (EDC), catechin table gallic catechin gallic acid ester (EGCG), EDC/EGCG were used as crosslinking agent for collagen matraces,and the effect of crosslinking agent dosage on the physicochemical properties of collagen was investigated. The shrinking temperature, water absorption, anti-enzymatic ability, morphological changes were characterized for the evaluation of the performance before and after collagen cross-linking.The results demonstrate that,after the crosslinking,the morphological stability and the enzymatic resistance all improved significantly.And the collagen cross-linked by EGCG had a stronger enzyme-resistant than by EDC.It is thus concluded that the EDC,EGCG,EDC/EGCG crosslinking greatly improves the physicochemical properties of collagen.4Performance and Preparation of the Scales Material Adsorption EGCGIn order to make a detailed investigation on the EGCG adsorption of tilapia scale as raw material, the preparation methods, the adsorption mechanism and the optimized adsorption technology were studied. Based on the results, the most reasonable interpretation of the data indicates that the EGCG adsorption material preparation process was under these conditions, the particle size of0.30--0.45mm at pH7at the temperature of110℃within20min with the solid to liquid ratio (g/mL)1:6. And EGCG capacity at23.53mg/g was got; Scale adsorption EGCG was the result of ash and protein joint action, when the ratio of ash and protein in1.08:1had maximum of adsorption capacity; Static experiments showed that the adsorption equilibrium achieved within40min and the adsorption efficiency decreased with the increase of sample concentration. Followed by eluting the scales with50%ethanol, the best desorption efficiency of EGCG in comparison with the total practical samples was obtained. The desorption equilibrium achieved within100min.Eluting liquid ratio (g/ml) of1:28had the best effect. Desorption2second best. It had strong adsorption and separation capacity for EGCG, which was hopeful applied in separation and purification of EGCG.5Study on the extraction of carotenoids,identification,oxidation resistance and stability from fishtailIn order to research the antioxidant activity compounds of fishtail pigment, used ethanol as extraction solvent, and the extraction process of antioxidant component was studied by means of extraction rate and DPPH free radical scavenging. The results showed that the better antioxidant components extraction conditions were extracted1time at20℃for24h with solid-liquid ratio (g/mL)1:5by solvent ethanol. Under this condition, the antioxidant components extraction rate reached to2.40%of the fish tail wet weight, the clearance of DPPH free radicals to58.44%.The color of fishtail was analyzed by color reation,ultraviolet, Rf,confimed that the major components of the extract pigment is kind of carotene.And arotenoids compound of persimmon peel were separated and purified by thin layer chromatography(TLC). Five kinds of main ingredient in the persimmon peel were determined by TLC, the Rf were0.303,0.578,0.627,0.675,0.902, respectively. Through the main experiments, the optimal separation condition of cotuaanl chromatography was:Antioxidant activities of extract were evaluated by three different methods, such as DPPH and ABTS radical scavenging assay, potassium ferricyanide reduction method. The results showed that the experiments of antioxidant activity showed that the extracted fishtail pigment presents the strong antioxidant activity to the DPPH and ABTS radical, and the IC50was0.3891mg/mL and1.8654mg/mL, respectively.In this study, effects of temperature, metalion, HC1, NaOH, light and H2O2VC and common food additive on stability of carotenoids from fishtail were investigated. It was found that high temperature (more than60℃) and Ag+、Cu2+、Fe2+、Fe3+、Al3+may lead to great loss of carotenoids. Moreover,HCl with low concentration(<0.01mol/L) had little effects on the stability of carotenoids, while high concentration HCl(>0.01mol/L) or NaOH may easy to change. The carotenoids are sensitive to light and the damage effects of lights from different sources on stability of carotenoids as following:sunshine>ultraviolet light>fluorescent light>indoor light>dark in door. And the carotenoids are stable to H2O2, carotenoids were decomposed when high concentraction(more than1%)exists.6Development of Extraction and Identifying Methods for collagen from Tilapia FishtailWith one aim of developing the elimination methods of the fat soluble pigment during the course of the tilapia fishtail pretreatment and the other aim of optimizing the extraction of collagen, we had studies on the concentration of guanidine hydrochloride, the amount of pepsin and the treatment time in various conditions. Consequently, it was found that the collagen purity was determined after we had the collagen types being identified. The results showed that the best solution for the removal of the pigment under these conditions. Mixture of solvent chloroform:methanol:water=1:2:0.8, the solid-liquid to ratio (g/mL)1:15, time of36h, under these conditios the rate of pigment removal reached2.85%of the fish tail wet weight. The optimum extraction craft of collagen has also been achieved with the following proposed method by orthogonal array design, guanidine hydrochloride concentration3mol/L, the amount of pepsin added3.0%(w/w), time of72h, the solid-liquid to ratio (g/mL)1:50, extracted2times; under this condition, the collogen extraction rate reached4.96%of the fish tail wet weight, occupied40.39%of the fish tail thick protein; the extract collagen of content reached to94.63%, and the type of collagen was I.