Phenolic Compounds in Plant-Based Milk Alternatives from the Greek Market

Plant-based milk alternatives (PBMAs) are plant-based fluid products that are marketed as substitutes for regular milk. The nutrient composition of PBMA products can vary widely, depending on the plant source, processing methods, potential additives, etc., and in recent years, considerable research effort has been devoted to the exploration of the nutritional content of PBMAs, which are increasingly consumed worldwide. In the present study, an established UHPLC–Orbitrap MS method was employed for the extensive characterization of phenolic compounds in PBMAs available in the Greek market. Twenty-eight PBMAs were studied, including a variety of almond-, soy-, coconut-, oat-, walnut-, and rice-based products. In almond-based milk products, low total concentrations and a broad distribution across compound classes were observed, with trans-chlorogenic acid and neochlorogenic acid being the most abundant constituents, whereas coconut-based milk samples were generally not rich in phenolic compounds. In soy-based milk samples, the presence of isoflavones including daidzein, genistein, and glycitein was uniquely detected, while oat-based products were the samples richer in phenolic content, in particular for hydroxycinnamic acids, such as trans-chlorogenic acid and neochlorogenic acid. In addition, a suspect screening approach, using Exactive Plus Orbitrap, enabled the exploration and semi-quantification of three avenanthramides (A, B, C) in the studied oat-based milk samples and six isoflavonoids, namely daidzein and genistein derivatives, in soy-based milk. Such compounds are known for their antioxidant and anti-inflammatory properties, and their occurrence in PBMAs highlights the potential health-promoting effects of these dairy alternatives.