Application Of Near Infrared Spectroscopy In The Adulteration Of Ganoderma Lucidum Extraction

As a functional food with rich nutrient, Ganoderma lucidum extract or its products has been consumed more and more. But there exist some new quality problems, such as adulteration of cheap polysaccharide. It is serious threat to the edible fungi processing industry of Chinese. Near-infrared spectroscopy technology, as a rapid, nondestructive, and convenient analysis technique, has been widely used in the petrochemical industry, food industry, pharmaceutical industry and other fields. Aiming to the detection of the main adulteration of Ganoderma lucidum, we optimized the near infrared spectroscopy quantitative analysis method from parameters selection, sample outlier and model estalishment. The results were as following:(1)The partial square(PLS) prediction models for determination the polysaccharide of Ganoderma lucidum extraction were established. The PLS calibration models were established with the optimized pretreatment method. The polysaccharides reference values were determinated with phenol-sulfuric acid method. The correlation coefficient(R), the root mean square error of cross validation(RMSECV), and the best factor of the PLS model were 0.9817, 0.0142 and 6, respectively. Pairly comparion results showed that there was no significant difference between the prediction result and the reference. The cross-validation and external validation verified the reliability and repeatability of the model.(2) Near infrared spectra of Ganoderma lucidum extraction samples were obtained and a qualitative analysis model was established. Analysis results showed that one sample was outlier and should be deleted. The best PCR model gave the correlation coefficient of 0.9465, when the best factor, pretreatment and the optimum wave number range were 4, MSC+SD, and 7654~6987 cm-1、5534~4000 cm-1, respectively. In the PLS model, it also gave the correlation coefficient of 0.9656, when the best factor, pretreatment and the optimum wave number range were 6, FD, and 9150~4000 cm-1, respectively. Both the two models had the correct rate of 100%, according to the paired sample test, the result of PCR prediction had no significant difference compared with those by PLS. The research showed that the near infrared spectroscopy combined with PCR and PLS models provide an accurate and reliable new method to rapidly and nondestructively recognize authentication and adulteration of the Ganoderma lucidum extraction.(3) To explore a rapid prototype to determine Ganoderma lucidum extraction adultered with starches, a correlative model consists of near infrared spectrum and the contents of adulteration was established. Three kinds of wavelength region selection algorithm were designed –interval partial square(i PLS), backward interval partial least squares(Bi PLS), and forward interval partial least squares(Fi PLS). These algorithms were used to select optimal region. The result shows that these algorithms can improve the model accuracy. The performance of Fi PLS model was best in the three methods, and the optimal model was achieved with R =0.9957, RMSEP= 0.0258 in prediction set, respectively.All of these suggested that near infrared spectroscopy has good potential to quantitative and qualitative detected Ganoderma lucidum extraction rapidly and non-destructively.