Detection of Adulterant in Aloe Barbadensis Miller Gel Using Fourier Transform Infrared Spectroscopy (FTIR) with Chemometrics

Chen, Su-Yen (2025) Detection of Adulterant in Aloe Barbadensis Miller Gel Using Fourier Transform Infrared Spectroscopy (FTIR) with Chemometrics. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

Aloe barbadensis miller , more commonly known as aloe vera, is widely used for various applications such as cosmetic, food and pharmaceutical industries due to its significant anti-inflammatory properties. Adulterated A. barbadensis miller gel with cheaper substitutes such as maltodextrin would not cause any safety issues to arise, but poses notable challenges in terms of the product’s quality and efficacy. The main purpose of the study is to investigate the adulteration in A. barbadensis miller gel through the application of Fourier transform infrared spectroscopy (FTIR) coupled with chemometrics techniques, particularly Partial Least Square (PLS) and Partial Least Squares Discriminant Analysis (PLS-DA). This study analyses training data set of adulterated aloe vera gel with 0%, 2%, 4%, 6% to 8% of maltodextrin (n=30) and testing data set of commercially available aloe vera gels (n=18). Through the application of chemometric technique, complex FTIR spectral data (X variable) can be analysed and be presented through PLS-DA to reveal the clustering between pure and adulterated aloe vera samples. The viscosity and anti-inflammatory properties of the aloe vera samples, represented as the Y variables, are analysed in relation to the X variables using PLS, providing insight into the correlation between the samples and their respective physical properties and biological activity. Statistical data reveals that brand A aloe vera gel may contain 2% of maltodextrin while brands B and C aloe vera gel may contain 0% and 4% of ethanol respectively. This study provides a reliable analytical approach for the detection of adulterants in aloe vera gel as well as to ensure the authenticity of the aloe vera gel products in the market, thus safeguarding the quality and effectiveness of the product.