Pseudocereal-Based Functional Beverages: Main Properties and Nutritional Evaluation with an Emphasis on Amino Acid Content: A Review.

The demand for functional beverages has increased significantly in recent years as society places more and more emphasis on healthy lifestyles and disease prevention. Functional beverages may contain various health-promoting, bioactive compounds (e.g., antioxidants, vitamins, minerals, prebiotics, probiotics, proteins, etc.). These ingredients originate from sources including fruits (e.g., red berries), vegetables (e.g., spinach), nuts (e.g., flaxseeds), and herbs (e.g., turmeric), or can be added as separate components (e.g., prebiotics). Their nutritional properties qualify pseudocereals (quinoa, buckwheat, and amaranth) as ideal bases for functional beverages. They are high in antioxidants (e.g., polyphenols), vitamins (e.g., folate), and minerals (e.g., iron). Their high protein content (5.7-25.3%, about three times higher than that of maize) improves the nutritional profile of plant-based drinks. They have a balanced protein and amino acid composition, as they contain all the essential amino acids (among which lysine is present in high amounts) and are gluten-free. The in vitro protein digestibility of pseudocereals is also outstanding (PDCAAS: quinoa (0.85), amaranth (0.70), and buckwheat (0.78), while those for wheat, rice, and maize are 0.42, 0.56, and 0.47, respectively). Given these benefits, trends in producing and consuming plant-based, especially pseudocereal-based, functional beverages are highlighted in the present review.