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.

Fatty-acid-based nitroalkenes have recently received great attention because of their bioactivities. On the contrary, peptide- or amino-acid-based nitroalkenes have been scarcely explored so far, although they may exhibit interesting biological properties, for example, as enzyme inhibitors. In this work, we study protocols for the efficient synthesis of nitroalkenes based on natural amino acids. A variety of N-protected amino alcohols and Weinreb amides, derived from α-amino acids, were converted to the corresponding N-protected amino aldehydes, and, through a Henry reaction with nitroalkanes, produced the corresponding nitro alcohols. The subsequent elimination reaction led to the (E)-isomer of amino-acid-based nitroalkenes in moderate to high yields.

Olive oil production generates large amounts of agricultural and agro-industrial residues, with olive leaves representing one of the most abundant by-products. This study investigated the valorization of olive leaves from two Greek cultivars, Koroneiki and Megaritiki, collected from the Aeghion, Heraklion, and Megara regions, by means of an optimized green extraction process for the effective recovery of phenolic compounds. Response surface methodology (RSM) was applied to optimize solvent composition and extraction time using ethanol/water mixtures (0/100, 30/70, 50/50, and 70/30, v/v) and extraction times ranging from 15 to 90 min. Total phenolic content (TPC), antioxidant activity (DPPH and FRAP), and color parameters were determined spectrophotometrically, while individual phenolic compounds were analyzed by HPLC-DAD. Both solvent composition and extraction time significantly affected phenolic recovery and antioxidant activity. The optimal extraction conditions were 37.5/62.5 (v/v) ethanol/water and 52.5 min. Extracts from Megara showed the highest TPC (32 ± 1 g GAE kg⁻¹ LL), antioxidant capacity (2556 ± 162 mmol Trolox kg⁻¹ LL), and phenolic compound levels. Significant differences were observed between the two cultivars, whereas Koroneiki samples from Heraklion and Aeghion exhibited similar phenolic profiles, indicating that cultivars had a greater influence than geographical origin.