Colored cereals: Extraction and purification of bioactive compounds (pigments)

Cereals are essential element of our diet, and research groups across the globe are extremely interested in colored grains because of their improved nutritional, antioxidant, and health-promoting benefits. Due to their appealing nutritional characteristics, colored cereal grains (brown, purple, black, blue, red, and pink) have drawn a lot of interest in recent years. One of the most common types of pigments is anthocyanins that give cereals their colors as well as their health advantages. Different grains have different anthocyanin compositions. Some of the most prevalent processes for extracting bioactive compounds/pigments from colored cereals include conventional solvent extraction (CSE), microwave-aided extraction (MAE), accelerated solvent extraction (ASE), and ultrasonication. The ASE methodology appears to be more suitable than the CSE method in isolating anthocyanins from colored grains, on the account of variation in anthocyanin content. In comparison to the MAE method, the process induced less structural modifications in anthocyanins. Using chromatographic and spectroscopic techniques, type of anthocyanins such as cyanidin, malvidin, delphinidin, petunidin, peonidin, and pelargonidin glycosides are purified, quantified, and characterized in various colored grains such as rice, maize, barley, and wheat. Due to the thermolabile nature of bioactive compounds in colored grains, their use as food colorant is limited and utilized in small scale as an ingredient in functional foods. This area should be given more attention in order to stabilize these bioactive compounds and introduce these pigmented cereal-based products to consumers on a large scale after thorough market analysis. Despite the fact that in vitro and in vivo research conclusively demonstrated that colorful cereals are advantageous to human health, human and clinical studies are to be conducted to back up these claims.