Identification Method On Adulterated Bovine Colostrum With Mature Milk Based On Dielectric Spectrum And Near-infrared Spectrum

Bovine colostrum is rich in nutrients but low in yield.It is a healthy drink that is in short supply.Eliminating adulterated colostrum from the source is directly related to the bovine colostrum and its dairy products quality,and consumer rights.At present,there has been no report on the identification of adulterated colostrum by using scientific detection methods.In recent years,Radio-frequency(RF)or Microwave(MW)and Near-Infrared Spectroscopy have been widely used in the study of liquid food quality analysis because of their high efficiency,simplicity,and capability of on-line detection.Therefore,these two test methods are used to explore the feasibility of identifying adulterated colostrum.Firstly,colostrum and colostrum with mature milk as the research object,open-ended coaxial probe technology is used to study the effect of the frequency(20-4500MHz)and the content of mature milk in colostrum on the dielectric property of colostrum at 25°C,and mechanism analysis;establishing the mathematical mode between the content of mature milk in adulterated colostrum and the dielectric parameters of adulterated colostrum;and then using chemometrics to study the methods of detecting the adulterated colostrum or the content of mature milk in adulterated milk based on the dielectric spectrum.Secondly,colostrum and colostrum with mature milk as the research object,Near-Infrared Spectroscopy is used to study the effects of the wavelength(833-2500nm)and content of mature milk in colostrum on the optical properties of adulterated colostrum;and then using chemometrics to study the methods of detecting the adulterated colostrum or the content of mature milk in adulterated milk based on near-infrared spectrum.Finally,comparing the modeling results based on near-infrared spectrum with those based on dielectric spectrum.The conclusions are as follows:(1)In the measured frequency range,with the increase of frequency,the ?' of cow's milk decreased but the ? " decreased first,and then increased.The ?" had a minimum value at about 1800 MHz.In the measured content of mature milk range(0-50%,10% span),the?' of adulterated colostrum increased while ? " decreased with the increase of the content of mature.The ?' and ?" of adulterated colostrum as function of content of mature milk could be accurately described by linear equation with one unknown.(2)A qualitative model for the identification of adulterated colostrum was established based on dielectric spectroscopy.The results show that the model based on partial leastsquares discriminant analysis(PLS-DA)has the highest detection accuracy of 97.30%,and the prediction accuracy of colostrum and adulterated milk is 100% and 96.00%,respectively,which can meet the requirements of production and use.(3)In the measured near-infrared wavelength range,the colostrum and the mature milk change regularly withe the increase of wavelength.In the measured content of mature milk range(0-50%,10% span),there was no significant relationship between the absorbance of the adulterated colostrum and the content of mature milk in adulterated colostrum.And,establishing the qualitative model to detect adulterated colostrum based on near-infrared spectrum.The results show that,with dividing samples by KS methods and selecting characteristic variables by UVE,the ELM model had a high precision with the adulterated colostrum,the accuracy of prediction set was 88.46%,among them,the accuracy of colostrum and adulterated colostrum prediction set were 81.82% and 93.33%.(4)Comparing the modeling results of qualitative identification model of detecting the adulterated colostrum based on dielectric spectrum and near-infrared spectrum.It was found that the model based on the dielectric spectrum is generally better.This is because the RF or MW has very small scattering intensity and large penetration depth in milk,and it is less affected by scattering.(5)Further reduce the content of mature milk in the adulterated colostrum(0-10%,span 2%),study the effect of small content of mature milk in adulterated colostrum on the dielectric parameters of adulterated colostrum under a single frequency at 25 °C.It had found that the addition of mature milk in a small proportion does not cause a significant change in the ?' of the adulterated colostrum;when the content of mature milk is more than6%,the ?" of adulterated colostrum is significantly affected by the addition of mature milk.A large sample of adulterated colostrum with mature milk content of 0-50%(0-10%,span2%;10%-50%,span 10%)was obtained to establish the quantitative model to detect the content of mature milk in adulterated colostrum based on dielectric spectrum.The results show that,which dividing samples by SPXY methods and selecting characteristic variables by SPA,the SVM model had a high prediction precision with the content of mature milk in adulterated colostrum,the RMSEP and RPD of the model were 0.0344 and 4.85 respectively.Taking the adulterated colostrum samples with 0-10% mature milk as the research object,it was found that the prediction results were poor,and the SPA-GRNN model had the best prediction effect,but it could only give the magnitude of the prediction value,and its RMSEP was the smallest(0.0191).(6)A large sample of adulterated colostrum with mature milk content of 0-50%(0-10%,span 2%;10%-50%,span 10%)was obtained to establish the quantitative model to detect the content of mature milk in adulterated colostrum based on near-infrared spectrum.The results show that,which dividing samples by SPXY methods and selecting characteristic variables by SPA or FS,models had poor prediction results.Taking the adulterated colostrum samples with 10-50% mature milk as the research object,the prediction results of quantitative model were also poor.It is concluded that near-Infrared spectroscopy is not suitable for the prediction of the content of mature milk in adulterated colostrum.The study results suggest that dielectric spectroscopy combined with chemometrics can be used to detect the adulterated colostrum or the content of mature milk in adulterated colostrum.The near-infrared spectroscopy combined with chemometrics can be used to detect the adulterated colostrum,but it is not suitable for predicting the content of mature milk in adulterated colostrum.This research provides an experimental basis for the development of colostrum adulteration detection instrument based on dielectric spectroscopy,and are of great significance for the realization of colostrum quality monitoring.