Rapid Determination Of Lactose And Hydrolyzed Collagen In Dairy Products

With the rapid development of dairy industry, quality and safety problems of dairyproducts should be solved, which have become the focus of people’s concerns.In this thesis, lactose and hydrolyzed collagen were studied. The rapid determinationmethods and instruments were developed. These methods were successfully applied for theanalysis of dairy products, and the results were satisfactory.The rapid portable analyzer was designed based on colorimetric method fordetermination lactose. The analyzer consists of Light Emitting Diode(LED), cylindricalcolorimetric bottle with stopper, thermo-resistant integrated optical sensors,microprocessor, LCD display module and keypress. The analyzer and the supporting kitused were studied. In the lactose concentration range of0.01g/L-0.1g/L, absorbance andconcentration of lactose had a good linear relationship. The method had been successfullyapplied to the determination of lactose in dairy products, obtained from50differentmanufactures and batches. The method was also applied for identification of adulterats.The results obtained by the method were in good agreement with the results obtained bythe national standard method.To detect hydrolyzed collagen, microwave-assisted hydrolysis was studied. Theanalyzer was applied to determination of the amino acid4-hydroxyproline (4-Hyp) in dairyproducts, and showed whether dairy products were adulterated with hydrolyzed collagen.The4-Hyp only exists in the collagen and the content of the4-Hyp is about10%. Theconcentration of4-Hyp had been used to identify hydrolyzed collagen and its content indairy products. The microwave-assisted hydrolysis was accurate and precise as thetraditional hydrolysis and the pretreatment time was reduced from16h to4-8min. Theoptimal conditions were studied by orthogonal experiments. The4-Hyp portable analyzerbased on colorimetric method was developed. To obtain good precision and stability, thefactors associated with the processes of color development had been studied.4-Hypportable analyzer had been successfully applied to determination of4-Hyp to detect possible adulterations of hydrolyzed collagen in dairy products. The calibration curve ofthe4-Hyp for determining exhibited lineane relationship (R=0.9998). The concentrationrange is0.05-2.5μg/ml and detection limit is0.01μg/ml. The recoveries are between95%and110%.