DETECTION OF ADULTERATION IN APPLE JUICE USING MID INFRARED SPECTROSCOPY

Abstract

Food authenticity is an issue of concern to food processors, regulatory authorities, and consumers alike. Theapplication of fourier transform infrared (FTIR) spectroscopy as an analytical tool for rapid determination of the type andlevel of sugar adulterants (beet and cane invert sugars) in apple juice was investigated. Spectrum of adulterated apple juicewas characterized and the region 8001500 cm 1 was evaluated using multivariate statistics. Linear discriminant andcanonical variate analysis were used to discriminate apple juice samples. An optimum classification of 100 and 96.2% wasachieved for discriminating apple juice samples adulterated with beet and cane invert sugar, respectively using lineardiscriminant analysis (LDA). Partial least square (PLS) and principal component regression (PCR) analyses were used todevelop calibration models to estimate the quantity of beet and cane invert sugar in apple juice. R 2 value for the predictionfor beet and cane invert sugars was around 0.98 using various chemometric methods. The standard error of prediction (SEP)in validation set was between 1.3 and 1.8% (w/w). Results demonstrated that FTIR spectroscopy along with chemometricmethods could be used for rapid detection of adulteration in apple juice. Additionally, identifying the type of adulterant, whichis an elaborate process, can be achieved rapidly using the proposed technique.