| Loquat Loquat （Eriobotrya japonica） is one of the six subtropical fruits in Fujian province.Fujian Putian is known as " The township of Loquat". Loquat paste is made by pure loquat pastewithout peel and nuclear according to traditional method. It was demonstrated that loquat pastehas a significant effect on eliminating phlegm and nourishing lung. And metal container is thebest choice to produce loquat paste, for this traditional method has been known for a long time. Inorder to make this traditional food become industrialization, research of basic theory andapplication were carried out in this topic. Aiming to establish a complete set of processing ofloquat paste, and demonstrate its unique efficacy and the functional composition scientifically.1. Vacuum concentration and atmospheric concentration process of loquat paste is optimized,the terminal point of loquat paste was determined. Comprehensive comparison of the effect ofvacuum concentration, atmospheric concentration process to the total antioxidant capacity ofloquat paste was taken, and obtaining the best concentration processing technology. The resultsshow that the optimal technical parameters for atmospheric concentration of loquat paste were:iron pot was chose as the container, concentration temperature90-100℃, stirring speed30rmp,vacuum degree-0.095MPa, terminal point60°Brix.2. Rheological property of loquat paste is determined by studying relationship betweendifferent viscosity and temperature. According to the results, loquat paste was shown asnon-Newtonian pseudo-plastic fluids, in the range of researched concentration and temperature.By regression analysis, The effect of temperature on viscosity of loquat paste could be describedby an Arrhenius type equation：η=kexp（Ea/RT）, and the effect of concentration on viscosity ofloquat paste could be described by an Index type equation：η=Bexp（AC）. Finally，a mathematicalmodel：η=K1exp（Ea/RT+K2C+K3C2），which described the combined effect of temperature andconcentration on the loquat paste viscosity was obtained, with applicable range of20-60℃, and45-60°Brix concentration.3. Comparing the antioxidant activity of original loquat paste and loquat paste duringprocessing process. Total antioxidant ability, remove DPPH radical ability, clear the hydroxylradicals ability, remove superoxide ability were chose as the antioxidation index, in order toestablish a antioxidation ability evaluation system through atmospheric concentration process of loquat paste, and make a comparation with the Nin Jiom Pei Pa Koa Chuanbeipipa syrup and Panlong life ChuanBei Chuanbeipipa syrupt. The results indicate that loquat paste made by iron pot,with stirring speed30rmp, under90-100℃, there is a significant improve on the antioxidantcapacity compared with original loquat paste, and is better than the Nin Jiom Pei Pa KoaChuanbeipipa syrup and Pan long life ChuanBei Chuanbeipipa syrup. It was illustrated that thetraditional process has a benefit on improving the antioxidation ability of loquat paste.4. The content of reducing sugar, amino acids, polyphenol, vitamin C, metallic iron,5-HMFand other major typical properties in the Loquat paste during processing process was studied.Results show that non-enzymatic browning occurred during the processing is mainly Maillardreaction. And the browning level was increased with the rise of concentration. It seemed that thereaction product has made a contribution to the antioxidation. The oxygenolysis of vitamin C hashappened during the concentration, what’s more the metallic iron promoted the browning reaction,and catalyzed non-enzymatic browning which could generate macromolecular material withantioxidation activity. There was not a great change of the polyphenol content, but polyphenol hasantioxidation itself.5-HMF content showed a obvious trend of increasing during the concentrationprocess. There was a Maillard reaction between alkaline amino acids with hydroxyl groups andreducing sugar during processing. And the reaction product was benefit to improve theantioxidation of loquat paste. The content of acidic amino acids with hydroxyl groups andreducing sugar was decreased significantly. However, there was a slight change of nonpolaramino acids. |
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