This cluster of papers explores the properties, sources, applications, and stability of betalains, particularly in relation to their antioxidant activity, nutritional significance, and potential health benefits. The research covers a wide range of topics including the extraction, characterization, and bioavailability of betalains from various plant sources, with a focus on Opuntia species. Additionally, the cluster delves into the use of betalains as natural colorants and their potential role in functional foods.