Sorghum grain (Sorghum bicolor L. Moench) is a staple food grown across the globe, and is mainly cultivated in the semi-arid regions of Africa and Asia. Recently, sorghum grain is increasingly utilized for human consumption, due to the gluten-free nature and potential phenolic-induced health benefits. Sorghum grain is rich in bioactive phenolic compounds, such as ferulic acid, gallic acid, vanillic acid, luteolin, and apigenin, 3-deoxyanthocyanidins (3-DXA), which are known to provide many health benefits, including antioxidant, anti-inflammatory, anti-proliferative, anti-diabetic, and anti-atherogenic activities. Given an increasing trend of sorghum consumption for humans, this article reviews the content and profile of phenolics in sorghum. It covers aspects of their health benefits and explores their mechanisms of action. The impact of thermal processing, such as boiling, steaming, roasting, and extrusion on sorghum phenolics is also discussed. Compelling data suggest the biological functions of sorghum phenolics, however, further investigations appear warrant to clarify the gap in the current research, and identify promising research topics in future.

With continuous global population growth, the challenges of expanding demand for sufficient and nutritious foods need to be addressed by exploring new and supplemental agricultural and food systems. Duckweed demonstrates a great potential for human food with many advantages. This review covers recent research on duckweed regarding plant cultivation, nutritional composition and quality, product development, and related safety issues and regulations for human food uses. Challenges and future research needs are discussed. Species and cultivation conditions have a significant effect on chemical and nutritional compositions of duckweed. Certain duckweed species contain high protein content (up to 45%) that provides all the essential amino acids meeting FAO references and can support human body growth and development. Duckweed also contains versatile carbohydrates including starch, cellulose, trace hemicellulose, and pectin that deliver functional properties and nutrients. In addition, duckweed is rich in minerals, vitamins, and phytochemicals, especially lutein and β-carotene which are positively associated with reduced risk of many chronic diseases. Duckweed could be used either in conventional cereal-based foods by partial substitution of wheat flour or for extraction of proteins and phytochemicals as functional ingredients. Studies are warranted for developing a duckweed supply chain and establishing duckweed as a novel staple food.

In vitro cell culture models on monolayer surfaces (2D) have been widely adapted for identification of chemopreventive food compounds and food safety evaluation. However, the low correlation between 2D models and in vivo animal models has always been a concern; this gap is mainly caused by the lack of a three-dimensional (3D) extracellular microenvironment. In 2D models, cell behaviors and functionalities are altered, resulting in varied responses to external conditions (i.e., antioxidants) and hence leading to low predictability. Peptide hydrogel 3D scaffolding technologies, such as PGmatrix for cell culture, have been recently reported to grow organoid-like spheroids physiologically mimicking the 3D microenvironment that can be used as an in vitro 3D model for investigating cell activities, which is anticipated to improve the prediction rate. Thus, this review focuses on advances in 3D peptide hydrogels aiming to introduce 3D cell culture tools as in vitro 3D models for cancer-related research regarding food safety and nutraceuticals.

Phenolic compounds in some specialty sorghums have been associated with cancer prevention. However, direct evidence and the underlying mechanisms for this are mostly unknown. In this study, phenolics were extracted from 13 selected sorghum accessions with black pericarp while F10000 hybrid with white pericarp was used as a control, and cell growth inhibition was studied in hepatocarcinoma HepG2 and colorectal adenocarcinoma Caco-2 cells. Total phenolic contents of the 13 high phenolic grains, as determined by Folin–Ciocalteu, were 30–64 mg GAE/g DW in the phenolic extracts of various accessions compared with the control F10000 at 2 mg GAE/g DW. Treatment of HepG2 with the extracted phenolics at 0–200 μM GAE up to 72 h resulted in a dose- and time-dependent reduction in cell numbers. The values of IC₅₀ varied from 85 to 221 mg DW/mL while the control of F10000 was 1275 mg DW/mL. The underlying mechanisms were further examined using the highest phenolic content of PI329694 and the lowest IC₅₀ of PI570481, resulting in a non-cytotoxic decrease in cell number that was significantly correlated with increased cell cycle arrest at G2/M and apoptotic cells in both HepG2 and Caco-2 cells. Taken together, these results indicated, for the first time, that inhibition of either HepG2 or Caco-2 cell growth by phenolic extracts from 13 selected sorghum accessions was due to cytostatic and apoptotic but not cytotoxic mechanisms, suggesting some specialty sorghums are a valuable, functional food, providing sustainable phenolics for potential cancer prevention.

The effect of extrusion processing on water-soluble dietary fiber (SDF) and water-insoluble dietary fiber (IDF) of whole grain highland barley (HB) in terms of morphology, physicochemical and functional properties, and antioxidant activities was studied. Extrusion processing resulted in the more porous and loose structure of SDF and IDF, and significantly increased the specific surface area of SDF and IDF. The predominant monosaccharide in IDF and SDF was cellulose. Extrusion processing improved the water holding capacity of SDF and IDF by 23.9% and 40.4%, respectively. The glucose absorption capacity and glucose dialysis retardation index of IDF and SDF were further significantly improved by extrusion processing, indicating the great potential of glucose control in vitro of IDF and SDF. The cholesterol adsorption capacity, nitrite adsorption capacity, and cation exchange capacity of IDF and SDF were also significantly improved through extrusion processing. Extrusion processing significantly improved the antioxidant activities of IDF and SDF which reflected as the improved DPPH and ABTS⁺ scavenging activities. Taken together, extrusion processing improved the physicochemical and functional properties of dietary fiber of whole grain HB, as well as the antioxidant activities. This study showed the great potential of dietary fiber of whole grain HB in the applications of functional foods for improving the health benefits.