Study On Processing Technology And Stability Of Clarified Juice From Chaenomeles Speciosa S.Nakai And Crisp Pear

Because the juice of Dangshan pear has no special aroma, and its flavor was not goodenough, acid amount was low, colour and lustre was bad etc. The juice of Chaenomelesspeciosa S.Nakai with special aroma and rich sour was used to compound. The two kindsof juice were compounded with the prospective tastes and nutrition to improve the quality.The experiment focused on the preparation process of the composite clarified juice ofChaenomeles speciosa S.Nakai and Dangshan pear, and the allocation and stability ofproduct were also investigated. The main findings were as follows:1. The color stability was investigated in the preparation process of Danshan Pearjuice. Different concentration gradient0.01%,0.02%,0.03%of citric acid solution, sodiumerythorbate solution, sodium ascorbate solution, and Sodium bisulfite solution were chosenrelatively. Pears with peeled and unpeeled were soaked by these color protection about15~20minutes. The results showed that the effect of color protection on the peeled pears wasnot ideal. The juice was squeezed by these pears browning heavily. However, the effect onthe unpeeled pears was significant.0.03%sodium ascorbate solution was considered as thebest way to protect the colour by compared the four color protection affecting on the juicequality.2. Pear juice was prepared by the process of pulp enzyme treatment. The optimumprocess parameters were: the addition of pulp enzymes was0.06%, the hydrolyzingtemperature was50℃, the hydrolyzing time was2h. The parameters were determined bysingle factor and orthogonal experiments. After the juice was centrifuged10minutes at3600r/min, the light transmission of juice was measured95%.3. The extraction process parameters of Chaenomeles speciosa S.Nakai juice weredetermined. The add water ratio, extraction time and temperature on the quality of theextracted juice were showed by single factor test. Orthogonal test was designed todetermine the best extraction process parameters. The results showed that when addingwater multiples were3times, holding time was6hours, and the extraction temperaturewas50℃, the quality of juice was better.4. The experiment of the screening clarify methods of Chaenomeles speciosa S. Nakai.The following seven kinds of clarification methods were used: The transmittance was86.9%when juice was centrifuged for15minutes at3600r/min; The transmittance was90.1%when standing on at room temperature for24hours; When clarified juice washeated, the transmittance was95.7%; When juice was freezed six hours, the transmittancewas96.5%; When0.06%PVPP was added in the juice and standing at room temperature for3hours, the transmittance was90.1%; When0.3g/l chitosan was added and standingabout30min at50℃, the transmittance was95%; When0.03%pectin enzyme was addedin the juice and standing on2hours at45℃, the transmittance was92%; The transmittanceof juice was achieved more than90%by six methods in addition to the centrifugalclarification method by comparison. Compared with the different clarified methods on thequality of juice, chitoson had less effect on the juice. Thus, the addition of chitosan about0.3g/l, the clarification time for30min, and the clarification temperature at50℃were thebest parameters.5. Complex program of Danshan pear juice and Chaenomeles speciosa S.Nakai juice.Two clarified juice were used as raw materials and a variety of accessories were added inthe experiment to design an orthogonal experiment. The juice was scored according tocolor, smell and taste of the juice. The results showed that Chaenomeles speciosa S.Nakaijuice25%, pear juice25%, sucrose4%, honey2%were the best parameters. The testsshowed that the optimal combination of the stabilizer was0.06%sodium alginate+0.01%xanthan gum+0.03%CMC-NA. The best sterilization conditions of Composite juice wastemperature90~95℃, time15~20min.6. In the test of the storage stability of the compound juice. The juice was stored in therefrigerator and room temperature respectively. Changes of juice qualities were observed atregularly time. The results showed that the qualities of compound juice were better afterstored in refrigerator (4℃)6months, as the juice color was still pale yellow and bright,and no sedimentary, no layering phenomenon.