Investigation of Maillard reaction products in plant-based milk alternatives

Over the past decade, plant-based milk alternatives (PBMAs) have gained increasing popularity. Several processing technologies, including heat treatment, are usually employed during their production in order to replicate the properties of cow's milk. These processes can trigger the Maillard reaction, producing Maillard reaction products (MRPs) and amino acid cross-links, which may alter the nutritional profile and digestibility of PBMAs. This study investigates PBMAs available in the Scandinavian market to assess their MRP and amino acid cross-link concentrations, aiming to understand the relationship between the formation of these heat-induced compounds and the specific chemical composition of individual PBMAs. Two types of UHT-treated cow's milk and ten UHT-processed PBMAs from different brands were analyzed. Quantitative analyses included early-stage MRPs (Amadori products detected as furosine), intermediate MRPs (α-dicarbonyl compounds and furans), advanced glycation end products (AGEs), acrylamide, and amino acid cross-links (lanthionine and lysinoalanine). Protein, carbohydrate, and amino acid profiles were also assessed using LC–MS and HPLC methods. PBMAs were found to differ substantially in carbohydrate and protein content, with soy-based drinks containing higher protein and rice and oat drinks having more carbohydrates. Essential amino acid (EAA) levels were found lower in all PBMAs, impacting their nutritional quality. MRP levels, such as furosine and AGEs, varied across PBMAs, indicating different heat-processing intensities. Specific α-dicarbonyl compounds, like 3-deoxyglucosone, were more concentrated in PBMAs than in UHT-treated cow's milk, and compounds like HMF, furfural, and acrylamide were also found in some PBMAs. Finally, correlations were observed between sugar content, α-dicarbonyls, and AGEs, which offer insights into possible chemical transformations in PBMAs during processing.