Paper-based Device for the Detection and Quantification of Total Polyphenols in Plant-based Beverages for Potential Use in Quality Assurance Purposes

Abstract

Health benefits arising from polyphenols found in plants have driven a steady increase in the manufacture of polyphenol-rich, plant-based food products. In line with quality assurance and compliance to local and international regulations, the polyphenol content of these products needs to be ascertained by manufacturers. The measurement of the total polyphenol content (TPC) in such products, therefore, should be part of the quality assurance of food manufacturers. This study involved the development of a cheap, user-friendly, and robust paper-based device (PBD) that can be potentially used by small-to-medium enterprises (SMEs) in determining the TPC of tea-based beverages – specifically, sweet potato leaf extract-based (SPLE) tea beverage products. The PBD relies on colorimetric detection of TPC based on the iron tartrate (IT) spectrophotometric. Validation studies of the PBD yielded good accuracy and precision, with limits of detection (LOD) and quantification (LOQ) of 20.03 and 66.77 ppm gallic acid equivalents (GAE), respectively. The device also has good linearity and sensitivity. Likewise, the quantification of polyphenols using the PBD was not adversely affected by the presence of sugars and ascorbic acid. The PBD stored under refrigerated conditions remained usable for 57 d. The PBD’s performance was found to be comparable to its counterpart instrumental method.