Globally, sorghum is one of the most important but least utilized staple crops. Sorghum grain is a rich source of nutrients and health‐beneficial phenolic compounds. The phenolic profile of sorghum is exceptionally unique and more abundant and diverse than other common cereal grains. The phenolic compounds in sorghum are mainly composed of phenolic acids, 3‐deoxyanthocyanidins, and condensed tannins. Studies have shown that sorghum phenolic compounds have potent antioxidant activity in vitro , and consumption of sorghum whole grain may improve gut health and reduce the risks of chronic diseases. Recently, sorghum grain has been used to develop functional foods and beverages, and as an ingredient incorporated into other foods. Moreover, the phenolic compounds, 3‐deoxyanthocyanidins, and condensed tannins can be isolated and used as promising natural multifunctional additives in broad food applications. The objective of this review is to provide a comprehensive understanding of nutrition and phenolic compounds derived from sorghum and their related health effects, and demonstrate the potential for incorporation of sorghum in food systems as a functional component and food additive to improve food quality, safety, and health functions.

Diabetes is a global health challenge. Currently, an effective treatment for diabetes is to reduce the postprandial hyperglycaemia by inhibiting the carbohydrate hydrolysing enzymes in the digestive system. In this study, we investigated the in vitro α-glucosidase and α-amylase inhibitory effects of free and bound phenolic extracts, from the bran and kernel fractions of five sorghum grain genotypes. The results showed that the inhibitory effect of sorghum phenolic extracts depended on the phenolic concentration and composition. Sorghum with higher phenolic contents generally had higher inhibitory activity. Among the tested extracts, the brown sorghum (IS131C)-bran-free extract (BR-bran-free, half-maximal inhibitory concentration (IC50) = 18 ± 11 mg sorghum/mL) showed the strongest inhibition against α-glucosidase which was comparable to that of acarbose (IC50 = 1.39 ± 0.23 mg acarbose/mL). The red sorghum (Mr-Buster)-kernel-bound extract (RM-kernel-bound, IC50 = 160 ± 12 mg sorghum/mL) was the most potent in inhibiting α-amylase but was much weaker compared to acarbose (IC50 = 0.50 ± 0.03 mg acarbose/mL).

3‐Deoxyanthocyanidins are a rare type of anthocyanins that are present in mosses, ferns, and some flowering plants. They are water‐soluble pigments and impart orange‐red and blue‐violet color to plants and play a role as phytoalexins against microbial infection and environmental stress. In contrast to anthocyanins, the lack of a hydroxyl group at the C‐3 position confers unique chemical and biochemical properties. They are potent natural antioxidants with a number of potential health benefits including cancer prevention. 3‐Deoxyanthocyanidin pigments have attracted much attention in the food industry as natural food colorants, mainly due to their higher stability during processing and handling conditions compared with anthocyanins. They are also photochromic compounds capable of causing a change in “perceived” color, when exposed to UV light, which can be used to design novel foods and beverages. Due to their interesting properties and potential industrial applications, great efforts have been made to synthesize these compounds. For biosynthesis, researchers have discovered the 3‐deoxyanthocyanidin biosynthetic pathway and their biosynthetic genes. For chemical synthesis, advances have been made to synthesize the compounds in a simpler and more efficient way as well as looking for its novel derivative with enhanced coloration properties. This review summarizes the developments in the research on 3‐deoxyanthocyanidin as a colorant, from natural sources to chemical syntheses and from health benefits to applications and future prospects, providing comprehensive insights into this group of interesting compounds.