Development Of The New Analytical Methods Of Typical Stabilizers Phosphates And Sodium Carboxymethyl Cellulose In Dairy Products And Its Application

In the processing of dairy products,stabilizers are often added to improve the quality of dairy products and extend their shelf life.Among them,phosphates and sodium carboxymethyl cellulose are the two most commonly used,and they are generally considered as safe to use.However,recent studies have found that there are still certain risks of excessive intake of phosphates or sodium carboxymethyl cellulose.Therefore,the construction of the analysis method of phosphates and sodium carboxymethyl cellulose in dairy products has a certain practical significance for the quality control of dairy products and the construction of the safety application technology system of stabilizer.Based on the literature review,this paper established the analytical methods of two typical stabilizers phosphates and sodium carboxymethyl cellulose in dairy products by ion chromatography and resonance scattering technique,respectively.Morevoer,the developed methods have been applied to study the content variation trend of the two stabilizers during the storage period of dairy products.The main research work of this article is as follows:1.A simple and reliable analytical method was established for the quantitative determination of five phosphates(orthophosphate,pyrophosphate,trimetaphosphate,tripolyphosphate and hexametaphosphate)in dairy products by ion chromatography(IC).The samples were deproteinized with 2%trifluoroacetic acid,defatted with n-hexane,and then purified on a C18 solid phase extraction cartridge.Five phosphates were separated on an IonPac^TM AS11-HC analytical column(250 mm×2mm)and an IonPac TM AS 11-HC guard column(50 mm×2 mm)with gradient elution of 30-60 mmol/L NaOH,then detected by a supressor type conductivity detector.The peaks area were linearly valuated with the concentration of the five compounds with good linear coefficients(not less than 0.9986).The limits of detection ranged from 0.1 mg/L to 0.6 mg/L.The average recoveries were within the range of 82.3?117.8%with the RSDs below 9.0%.The concentration of the five phosphates in the treated samples remained relatively stable within 48 h.The proposed procedure has been applied to the determination of the five analytes in several dairy product samples with satisfactory results.2.A new method was proposed for the determination of sodium carboxymethyl cellulose(Na CMC)in dairy products by resonance rayleigh scattering spectrometry.In the weakly alkaline medium,Na CMC can react with fuchsion to form a large volume ion-association complex.As a result of the reaction,intensity of resonance Rayleigh scattering(I_RRS)was enhanced significantly and a new RRS spectrum appeared.The two maximum scattering peaks were located at 320 nm and 600 nm for fuchsin-Na CMC.Under the optimal conditions,there is linear relationship between the relative intensity of RRS and concentration of Na CMC in the range of 0?10.0mg/L.Its regression equation was?I_RRS=43.427C-9.5235,with a correlation coefficient of 0.9974 and a detection limit of 0.028 mg/L.Moreover,the effects of foreign substances on the determination of Na CMC were investigated.Based on this,a new method was proposed for the determination of Na CMC in dairy products.This method has been applied to the determination of Na CMC in several dairy product samples with satisfactory results,and the average recoveries were within the range of86.9?112.6%with the RSDs below 5.7%.3.The established analytical methods were used to determine the content of the stabilizers phosphates and sodium carboxymethyl cellulose in dairy products during the storage process.At the same time,physical and chemical parameters such as p H,particle size,and ultraviolet absorption spectrum of the samples were analyzed.The change rule of the two stabilizers content during the storage process and their effect on the stability of dairy products have been studied preliminarily.