Sorghum is a unique natural food source of 3-deoxyanthocyanidins (3-DA) polyphenols. This work evaluated the effect of acidification on sorghum extracts post pressurized liquid extraction (PLE) and its ability to increase the identification and quantification of 3-DA. The sorghum genotypes included Sumac and PI570366 (bran only) and SC991 (leaf and leaf sheath tissue). The acidification of the PLE extracts was carried out with methanol–HCl solutions at various concentrations (0, 0.5, 1, 2, and 4%, v/v). Changes in color were determined using L*a*b*. The overall phenolic composition was estimated with the total phenolic content and the DPPH free radical scavenging assays. Quantitative and qualitative chromatographic methods determined the phenolic profile. Color analysis showed that the redness and color saturation increased after acidification. No statistical difference was found in the total phenolic content of the acidified extracts, except for SC991, which was increased. There were no differences in the antioxidant capacity following acidification in all samples. For chromatographic analysis, luteolinidin was predominant in the extracts and the 3-DA content increased after acid treatment. However, some flavonoid and phenolic acid concentrations decreased following acid treatment, including taxifolin, quercetin, and chlorogenic acid. Interestingly, 0.5% v/v HCl acidification was sufficient to increase the color, allow the detection of 5-methoxyluteolinidin, and to increase luteolinidin and 7-methoxyapigenidin by at least twofold.

Centipedegrass, Eremochloa ophiuroides [Munro] Hack., is a low‐maintenance, warm‐season turfgrass commonly grown in the southeastern United States. Limited information is known about the genomic regions that control centipedegrass traits, including stigma color. Stigma color can impact seed set and can have a role in insect pollination in other plant species. In this study, we used a genome‐wide association study to detect a genomic region on the Hi‐C genome assembler (HIC‐ASM)‐8 found to control stigma color. Examination of the most associated single‐nucleotide polymorphic (SNP) markers revealed that plants with a homozygous C/C allele had mainly purple stigmas but could be white or a mixture of colors, whereas accessions that were T/T for these loci had only white stigmas. Two candidate genes, ctg780.162 and ctg780.158, with homologs involved in anthocyanin accumulation, were identified near the most significant SNPs. The entire ctg780.158 gene was sequenced from multiple accessions, and the white stigma accessions contained a large insertion before the start codon. Similarly, white accessions (TT) had three SNPs in the ctg780.162 coding region as compared to purple accessions (CC). This study identified candidate genes for stigma color and characterized the utilization of the ctg780.158 insertion.

Rising rates of obesity and diabetes have increased demand for sugar-free products, while consumers also seek natural colorants and foods offering functional health benefits. Sorghum leaves, an underutilized part of the plant, contain health-promoting polyphenolic compounds with bioactive and coloring properties. Incorporating sorghum leaf-derived polyphenols into foods may meet both producer and consumer interest in natural colorants and value-added ingredients. This study aimed to incorporate sorghum leaf polyphenol extracts into sugar-free gelatin candies. Four formulations were produced: artificial-low color, natural-low color, artificial-high color, and natural-high color candies. Instrumental texture was evaluated using firmness and springiness measurements. Water activity was recorded using a water activity meter. Color was assessed with a colorimeter. Total phenolic content (TPC) was measured using the Folin–Ciocalteu assay. Consumers’ (N = 105) acceptance of sensory properties was evaluated using 9-point hedonic scales, and purchase intent was measured before and after colorant source and sweetener informational messaging. Natural colorant formulations had significantly higher water activity than artificially colored candies. Instrumental firmness and springiness differed significantly (p < 0.05) across formulations. However, these differences did not significantly (p > 0.05) impact consumer texture preference. TPC increased with higher levels of sorghum leaf extract but did not increase bitterness ratings. After receiving educational information about the colorant sources, purchase intent for the naturally colored formulations significantly (p < 0.05) increased, exceeding that of artificially colored candies. These findings demonstrate that sorghum leaf polyphenols can be successfully incorporated into sugar-free gummy candies and are well accepted by consumers as a natural colorant. This work supports sorghum as a value-added food ingredient, creating new market opportunities for US sorghum farmers.