Comparison of Common Analytical Methods for the Quantification of Total Polyphenols and Flavanols in Fruit Juices and Ciders

Abstract

Multiple analytical methods are used for quantification of total polyphenols and total flavanols in fruit juices and beverages. Four methods were evaluated in this study: Folin‐Ciocalteu (F‐C), Lowenthal permanganate (L‐P), 4‐dimethylaminocinnamaldehyde (DMAC), and the bovine serum albumin (BSA) precipitation method. Method validation parameters, including working range, limit of detection, limit of quantitation, precision (repeatability), accuracy, and specificity, were assessed and compared. The F‐C method was not specific to polyphenols, and the L‐P method had the widest working range but lacked accuracy. The DMAC method was the most specific to flavanols, and the BSA method was not suitable for quantification of smaller flavanols, such as catechin and epicatechin. Quantitative performance was evaluated using commercial fruit juice samples (n = 14), apple juice samples of different cultivars (n = 22), and commercial ciders (n = 17). In general, the L‐P titration method and DMAC method resulted in higher quantitative values than the F‐C method and BSA precipitation method, respectively. However, ratios of results obtained by the L‐P and F‐C method ranged from 1 to 28, and ratios of results obtained by the DMAC and BSA precipitation method ranged from <1 to 280. This tremendous variation is likely due to variation in polyphenol composition and sample matrix. This information provides perspective for comparison of results obtained through these different methods, and a basis for choosing the most appropriate analytical method for quantification of polyphenols to address a specific research question when working with commercial fruit juice, apple juice from different apple cultivars, and commercial ciders. Practical Application This study compared results obtained when four common polyphenol quantification methods were applied to a diverse selection of fruit juices and beverages with distinct polyphenol composition and sample matrix. The matrix and polyphenol composition of the samples significantly influenced the results. Our findings can help manufacturers of fruit‐based products choose the most appropriate analytical method for polyphenol quantification as part of a quality assurance program or to convey information on dietary polyphenol content to consumers. An assessment of analytical method validation parameters is provided for each of the four methods, which will help users of these methods to understand their limitations.

From untargeted metabolomics to the multiple reaction monitoring‐based quantification of polyphenols in chocolates from different geographical areas

“…These observation are in perfect agreement with the results presented in this paper that showed a great amount of (−)‐epicatechin in all the dark chocolate analyzed. Among all the chocolate specimens, samples from Ecuador and Peru showed the highest content of (−)‐epicatechin confirming previous reports 16,23 in good agreement with Ma et al 46 and Gottumukkala et al 47 data on (−)‐epicatechin quantification in commercially available dark chocolate containing 70% cocoa.…”

“…The concentration of these compounds is reported in Table 4 and Peru showed the highest content of (−)-epicatechin confirming previous reports 16,23 in good agreement with Ma et al 46 and Gottumukkala et al 47 data on (−)-epicatechin quantification in commercially available dark chocolate containing 70% cocoa.…”

Safety evaluation of aqueous extracts of Sanghuangporus vaninii fruiting body in Sprague–Dawley rats

“…The total content of polysaccharides was analysis according to phenol–sulfuric acid method (Masuko et al, 2005). The total content of polyphenols was measured using Folin‐Ciocalteu method (Ma et al., 2019). The major compounds were identified by high‐performance liquid chromatography (HPLC) and high resolution electrospray ionization mass spectroscopy (HR‐ESI‐MS) method (Huo et al., 2020).…”

Long-lasting effects of red and blue light exposure on the growth of soil fungi

“…Samples from liquid cultures were taken at the stage of active sporogenesis and used for measurements of protein and polyphenol contents in the mycelium. For this, Lowry method (Waterborg and Matthews 1994) and Löwenthal method (Protsenko and Kostina 2015;Ma et al 2019) were applied, respectively.…”