unveiling the power of handheld vis-nir spectroscopy and chemometrics for honey authentication

Honey, cherished for its distinctive sensory attributes, nutritional value, and health benefits, is a widely consumed plant-based natural food [1]. however, in recent times, honey has fallen victim to adulteration with cheaper sweeteners. shockingly, there have been reports of at least 21 different inexpensive sweeteners used for direct adulteration of honey. this adulteration has become so rampant that honey now ranks as the third most adulterated product, globally and within the european union, trailing only behind milk and olive oil [2]. the objective of this study is to devise an affordable, user-friendly, and time-efficient method for detecting and quantifying two common adulterants in honey using handheld visible-near-infrared (vis-nir) spectroscopy, combined with chemometric methods, specifically partial least squares-discriminant analysis (pls-da). to achieve this, we prepared four pooled samples from 18 authentic honey samples. these pooled samples were deliberately adulterated with glucose syrup and sugar syrup, and appropriate methods were employed for sample preparation, ensuring homogeneity at three different levels: low, medium, and high adulteration. the vis-nir spectra (400 to 1000 nm) of both pure and adulterated samples were recorded in two modes: reflectance and absorbance. the results from these two modes were compared to identify the more effective one. based on the models generated, we achieved remarkable results in detecting glucose syrup and sugar syrup adulteration in reflectance/absorbance mode, with accuracy rates of 87.5%, 80.95%, 86.3%, and 93.45%, respectively. additionally, this combined spectroscopic technique and chemometric approach could effectively differentiate between different levels of adulterants in honey samples. proton nuclear magnetic resonance (h nmr) is a powerful analytical tool which can be used for authenticating honey, at chemical constituent levels. in the last step of present work, we will compare the nir results with h nmr results as a reference method. this innovative approach holds great promise for ensuring the authenticity and quality of honey products, addressing the pressing issues posed by honey adulteration.