Changes in whole grain polyphenols and antioxidant activity of six sorghum genotypes under different irrigation treatments

Volatilomics and Lipidomics revealed flavoring mechanism in baijiu brewed from diverse Sorghum varieties

Sorghum is crucial in Baijiu brewing. Previous studies have shown that glutinous sorghum (LS) and non-glutinous sorghum (FS) significantly affect Zaopei's lipid metabolism and lipids affect flavor perception. This study aimed to explore the quality differences in Baijiu brewed with different sorghum varieties and the effects of lipids. Sensory evaluation, volatilomics, and lipidomics were used to analyze differences in flavors and lipids. The results showed that significant differences in flavor existed between the two types of Baijiu. The aged flavor of LS was more pronounced and its mouthfeel was smoother. However, the FS showed a more intense aroma release. In addition, FA 18:1;O3 (fatty acyls), acetaldehyde, and ethyl caprylate contributed to the smoothness and softness of Baijiu. These results suggest that the lipid composition of Baijiu affects its aroma and taste, thus providing a reference basis for selecting suitable raw sorghum materials to enhance the quality of Baijiu.

Grain bound polyphenols: Molecular interactions, release characteristics, and regulation mechanisms of postprandial hyperglycemia

Frequent postprandial hyperglycemia causes many chronic diseases. Grain polyphenols are widely recognized as natural active ingredients with high potential to treat chronic diseases due to their excellent postprandial hyperglycemic regulating effects. However, previous studies on polyphenols in grains mainly focused on the functional properties of free polyphenols and the extraction and physicochemical properties of bound polyphenols, ignoring the functional properties of bound polyphenols. Comprehensively understanding the binding properties of grain bound polyphenols (GBPs) and their mechanisms in regulating blood glucose levels is essential for developing and applying grain resources. This review summarizes the molecular interactions between GBPs and grain components and their effects on release characteristics and bioavailability at various stages. Meanwhile, the review focuses on elucidating the regulatory mechanism of post-release GBPs on postprandial hyperglycemia levels, incorporating insights from molecular docking, the gastrointestinal-brain axis, and gut flora. GBPs slow food digestion by occupying the active site of digestive enzymes and altering the secondary structure of enzymes and the hydrophobic environment of amino acid residues to inhibit enzyme activity. They modulate intestinal epithelial transport proteins (SGLT1, GLUT2, and GLUT4) to limit glucose absorption and increase glucose consumption. They also stimulate the release of short-term satiety hormones (CKK, GLP-1, and PYY) through the gastrointestinal-brain axis to decrease post-meal food intake. Furthermore, they optimize gut microbiota composition, promoting short-chain fatty acid production and bile acid metabolism. Therefore, developing functional foods with glucose-modulating properties based on GBPs is crucial for obesity prevention, diabetes management, and low-GI food development.

Effects of Mountain-Basin System on Chemical Composition, Antioxidant Activity and Volatile Flavor Substances of Cabernet Sauvignon Wines in Xinjiang Region, China

To investigate the effect of mountain-basin system on wine quality, four different regions were selected according to altitude and latitude. This work analyzed the differences in physicochemical properties, organic acids, monomeric phenols, antioxidant activity and volatile compounds of Cabernet Sauvignon wine between four regions. Comparative analysis revealed that there were significant differences in alcohol content and pH, respectively. Malic acid in organic acids was the main acid to distinguish the four regions. Correlation analysis showed that there was a significant correlation between physicochemical properties and climatic conditions in the four regions. There were significant differences in most of the monomeric phenols, and the antioxidant capacity was also significantly different. A total of 60 volatile compounds were detected, including 11 key volatile compounds, and there were significant differences in the composition of wines in the four regions. Methyl salicylate, ethyl caprate and ethyl hexanoate were the characteristic aromas in mountain front (MF) and intermontane basin (IB) regions, decanal was the characteristic aroma in sloping field (SF) region, and ethyl butyrate was the characteristic aroma in near desert (ND) region. This study further clarified the influence of climate and terrain on wine quality, and provided a better theoretical basis for the fine management of small producing areas.

Investigating the Impact of Sorghum on Tau Protein Phosphorylation and Mitochondrial Dysfunction Modulation in Alzheimer's Disease: An In Vitro Study

BACKGROUND

Alzheimer's disease (AD) is a progressive neurodegenerative disorder with poorly understood pathology. Elevated tau, phospho-tau and mitochondrial dysfunction are significantly correlated with an increased risk of AD and are therefore targets for disease-modifying therapy. In this study, we examined the effects of polyphenolic extracts from six different varieties of sorghum: Shawaya short black-1 (Black), IS1311C (Brown), QL33/QL36 (Red), B923296 (Red), QL12 (White), and QL33 (Red) on the attenuation of beta amyloid-induced phospho-tau levels, total tau levels, and mitochondrial dysfunction in neuronal cells.

METHOD

Tau proteins (231 (pT231), Serine- 199 (pS199), and total tau proteins (T-tau)) were detected and quantified using sandwich ELISA kits, while mitochondrial dysfunction was measured in terms of mitochondrial membrane potential (Δψm) and adenosine triphosphate (ATP) levels.

RESULTS

Almost all varieties of the sorghum extracts reduced the beta amyloid-induced pS199 and pT231 levels (p ≤ 0.05). The optimum concentration of QL33/QL36 (1000 µg/mL), QL12 (2000 µg/mL), and QL33 (2000 µg/mL) strongly attenuated the phospho-tau level. Sorghum IS1311C (750 µg/mL) showed the highest Δψm reduction (39.8%), whereas QL33 (2000 µg/mL) most strongly improved the ATP level (37.7%) (p ≤ 0.01). For both Δψm and ATP assays, the least activity was observed in sorghum B923296 at 21% and 25.5%, respectively (p ≤ 0.01).

CONCLUSIONS

The polyphenol extracts from sorghum attenuated the tau toxicity and Aβ-induced mitochondrial dysfunction in a variety- and dose-dependent manner and made a promising disease-modifying agent against AD. However, extensive research is needed to validate the efficacy of the sorghum extracts prior to animal and clinical studies.

Sorghum phytonutrients and their health benefits: A systematic review from cell to clinical trials

Sorghum is key for global food security due to its genetic variability, resilience, and rich phytonutrient content, which are linked to numerous health benefits. A systematic review assessed the health effects of sorghum by analyzing cell (n = 22), animal (n = 20), and human (n = 7) studies across antioxidant, anti-inflammatory, obesity, cancer, cardiovascular, and diabetes outcomes. This review, involving 42 papers and 177 researchers from 12 countries, collected data from sorghum accessions (acc) and significant effects. Studies used 68 identified and 8 unidentified sorghums, 57% red (n = 20), brown (n = 5), and black (n = 17) pericarp colors, and evaluated whole (n = 31), brans (n = 11), and decorticated grains (n = 2). Colored sorghum, richer in phenolic compounds, especially 3-deoxyanthocyanins and tannins, inhibited cancer cell activities, including proliferation, tumor growth, and ROS activity, and promoted cell cycle arrest and apoptosis. Sorghum elevated HO1 and eNOS expression for cardiovascular, health-reduced platelet aggregation, and modulated platelet microparticles. They also suppressed inflammation markers and decreased lipid accumulation. Animal studies indicated sorghum's potential across antioxidant capacity, cancer and inflammation mitigation, and lipid and glucose metabolism. Translating these findings to human scenarios requires caution, especially considering cell studies do not fully represent polyphenol metabolism. Human studies provided mixed results, indicating antioxidant and potential anti-inflammatory benefits and nuanced effects on glucose and lipid metabolism. The main risks of bias highlighted challenges in quantifying phytonutrients, identifying sorghum acc features, and lack of assessors blinding. Nonetheless, sorghum emerges as a promising functional food for countering chronic diseases in Western diets.

Genome-wide identification, evolution, and expression level analysis of the TALE gene family in Sorghum bicolor

BACKGROUND

The three-amino-acid-loop-extension (TALE) is a ubiquitous homeodomain transcription factor among plant species involved in regulating plant growth, development, and environmental responses. However, this has not been systematically analyzed or reported in sorghum.

RESULTS

In this study, 23 SbTALE genes were identified using bioinformatics and other methods at the genome level of sorghum, classified into two families, KNOX and BEL1-like family, and localized on ten chromosomes. One pair of tandem duplicated and seven pairs of segmentally duplicated genes were found, and the conserved motifs of SbTALEs among the same subfamilies were highly conserved, with highly conserved gene structures. SbTALEs genes have the most collinear genes with monocotyledonous Zea mays and are more closely related; SbTALEs have undergone purification and diversification selection in the evolutionary process. Overall, except for SbTALE21 and SbTALE23, the expression of the other six SbTALEs was higher in the stems, whereas the expression of SbTALE21 and SbTALE23 was higher in the leaves. In sorghum grain development, the lowest relative expression of SbTALEs was observed in grains in the late stage, and the expression of SbTALE21 was higher in grains in the early stage and husks in the late stage. In addition, SbTALE14 and SbTALE21 showed higher expression in the roots and stems under the cold treatment, and SbTALE02 and SbTALE12 showed higher expression in the roots and stems under the PEG treatment. Under the four hormone treatments, the expression of eight SbTALEs was relatively low in stems, the expression of SbTALE13 was higher in leaves than in roots and stems, and the expression of SbTALE23 was higher under the MeJA and SA treatments.

CONCLUSION

This study lays a theoretical foundation for the study of the biological function and mechanism of SbTALE genes and is of great significance for the mining of resistance genes and trait improvement.

Impact of Processing on the Phenolic Content and Antioxidant Activity of Sorghum bicolor L. Moench

Sorghum, a cereal grain rich in nutrients, is a major source of phenolic compounds that can be altered by different processes, thereby modulating their phenolic content and antioxidant properties. Previous studies have characterised phenolic compounds from pigmented and non-pigmented varieties. However, the impact of processing via the cooking and fermentation of these varieties remains unknown. Wholegrain flour samples of Liberty (WhiteLi1 and WhiteLi2), Bazley (RedBa1 and RedBa2), Buster (RedBu1 and RedBu2), Shawaya black (BlackSb), and Shawaya short black 1 (BlackSs) were cooked, fermented, or both then extracted using acidified acetone. The polyphenol profiles were analysed using a UHPLC-Online ABTS and QTOF LC-MS system. The results demonstrated that combining the fermentation and cooking of the BlackSs and BlackSb varieties led to a significant increase (p < 0.05) in total phenolic content (TPC) and antioxidant activities, as determined through DPPH, FRAP, and ABTS assays. The 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity of WhiteLi1, BlackSb, RedBu2, and BlackSs increased by 46%, 32%, 25%, and 10%, respectively, post fermentation and cooking. Conversely, fermentation only or cooking generally resulted in lower phenolic content and antioxidant levels than when samples were fully processed compared to raw. Notably, most of the detected antioxidant peaks (53 phenolic compounds) were only detected in fermented and cooked black and red pericarp varieties. The phenolic compounds with the highest antioxidant activities in pigmented sorghum included 3-aminobenzoic acid, 4-acetylburtyic acid, malic acid, caffeic acid, and luteolin derivative. Furthermore, the growing location of Bellata, NSW, showed more detectable phenolic compounds following processing compared to Croppa Creek, NSW. This study demonstrates that sorghum processing releases previously inaccessible polyphenols, making them available for human consumption and potentially providing added health-promoting properties.

Polysaccharide-polyphenol interactions: a comprehensive review from food processing to digestion and metabolism

Most studies on the beneficial effects of polyphenols on human health have focused on polyphenols extracted using aqueous organic solvents, ignoring the fact that a portion of polyphenols form complexes with polysaccharides. Polysaccharides and polyphenols are interrelated, and their interactions affect the physicochemical property, quality, and nutritional value of foods. In this review, the distribution of bound polyphenols in major food sources is summarized. The effect of food processing on the interaction between polyphenols and cell wall polysaccharides (CWP) is discussed in detail. We also focus on the digestion, absorption, and metabolic behavior of polysaccharide-polyphenol complexes. Different food processing techniques affect the interaction between CWP and polyphenols by altering their structure, solubility, and strength of interactions. The interaction influences the free concentration and extractability of polyphenols in food and modulates their bioaccessibility in the gastrointestinal tract, leading to their major release in the colon. Metabolism of polyphenols by gut microbes significantly enhances the bioavailability of polyphenols. The metabolic pathway and product formation rate of polyphenols and the fermentation characteristics of polysaccharides are affected by the interaction. Furthermore, the interaction exhibits synergistic or antagonistic effects on the stability, solubility, antioxidant and functional activities of polyphenols. In summary, understanding the interactions between polysaccharides and polyphenols and their changes in food processing is of great significance for a comprehensive understanding of the health benefits of polyphenols and the optimization of food processing technology.

Sorghum Grain Polyphenolic Extracts Demonstrate Neuroprotective Effects Related to Alzheimer's Disease in Cellular Assays

Sorghum grain contains high levels and a diverse profile of polyphenols (PPs), which are antioxidants known to reduce oxidative stress when consumed in the diet. Oxidative stress leading to amyloid-β (Aβ) aggregation, neurotoxicity, and mitochondrial dysfunction is implicated in the pathogenesis of Alzheimer's disease (AD). Thus, PPs have gained attention as possible therapeutic agents for combating AD. This study aimed to (a) quantify the phenolic compounds (PP) and antioxidant capacities in extracts from six different varieties of sorghum grain and (b) investigate whether these PP extracts exhibit any protective effects on human neuroblastoma (BE(2)-M17) cells against Aβ- and tau-induced toxicity, Aβ aggregation, mitochondrial dysfunction, and reactive oxygen species (ROS) induced by Aβ and tert-butyl hydroperoxide (TBHP). PP and antioxidant capacity were quantified using chemical assays. Aβ- and tau-induced toxicity was determined using the 3-(4,5-dimenthylthiazol-2-yl)-2,5-dimethyltetrazolium bromide (MTS) assay. The thioflavin T (Th-T) assay assessed anti-Aβ aggregation. The dichlorodihydrofluorescein diacetate (DCFDA) assay determined the levels of general ROS and the MitoSOX assay determined the levels of mitochondrial superoxide. Sorghum varieties Shawaya short black-1 and IS1311C possessed the highest levels of total phenolics, total flavonoids, and antioxidant capacity, and sorghum varieties differed significantly in their profile of individual PPs. All extracts significantly increased cell viability compared to the control (minus extract). Variety QL33 (at 2000 µg sorghum flour equivalents/mL) showed the strongest protective effect with a 28% reduction in Aβ-toxicity cell death. The extracts of all sorghum varieties significantly reduced Aβ aggregation. All extracts except that from variety B923296 demonstrated a significant (p ≤ 0.05) downregulation of Aβ-induced and TBHP-induced ROS and mitochondrial superoxide relative to the control (minus extract) in a dose- and variety-dependent manner. We have demonstrated for the first time that sorghum polyphenolic extracts show promising neuroprotective effects against AD, which indicates the potential of sorghum foods to exert a similar beneficial property in the human diet. However, further analysis in other cellular models and in vivo is needed to confirm these effects.

Exploring the Impacts of Sorghum (Sorghum bicolor L. Moench) Germination on the Flour's Nutritional, Chemical, Bioactive, and Technological Properties

Germination is a natural, simple, and economical process used to improve the quality of nutritional and technological grains. In this study, native and sprouted sorghum flours were characterized regarding their technological properties (particle size distribution, water, and oil absorption capacity, swelling power and solubility, microscopy of starch granules, and pasting and thermal properties). Nutritional and phytochemical characterization profiles, including free sugars, fatty acids, organic acids, tocopherols, and phenolic compounds, were explored through chromatographic methods. The antioxidant, anti-inflammatory, and cytotoxic activities of the respective hydroethanolic extracts were also evaluated. The results showed that the germination process caused significant changes in the flour composition and properties, causing reduced gelatinization temperature and retarded starch retrogradation; an increased content of free sugars and total organic acids; and a decreased content of tocopherols and phenolic compounds. In terms of bioactivity, the sprouted sorghum flour extract showed better lipid-peroxidation-inhibition capacity and none of the extracts revealed hepatotoxicity or nephrotoxicity, which are important results for the validation of the use of the flours for food purposes. Germination is an efficient and alternative method for grain modification that gives improved technological properties without chemical modification or genetic engineering.

Classification and characterization on sorghums based on HS-GC-IMS combined with OPLS-DA and GA-PLS

Headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) detected 206 and 186 samples of fresh and stored sorghums respectively with three major types in Baijiu industry. The fingerprints showed the differences of volatile compounds among fresh sorghum types by qualitative analysis and artificial recognition. Organic waxy sorghums had more contents of nonanal and 2-ethyl-1-hexanol but fewer ketones. The contents of acetoin in non-glutinous sorghums and organic non-glutinous sorghums were high. On the other hand, genetic algorithm-partial least squares (GA-PLS) selected 19 and 32 characteristic volatile compounds in fresh and stored sorghums. After centering and auto scaling to unit variance, the classification models with three major types of organic waxy sorghum, non-glutinous sorghum and organic non-glutinous sorghum were established based on orthogonal partial least squares-discriminant analysis (OPLS-DA). The goodness-of-fit (R2Y) and the goodness-of-prediction in cross-validation (Q2) in the model of fresh sorghum types all exceeded 0.9, in stored were over 0.8, the correct classification rates of external prediction were 95 % and 100 %, which revealed good performance and prediction. On this basis, the correct classification rates reached 87 % in organic waxy sorghums adulterated over 10 % ratio. GC-IMS combined with chemometrics is applicable in practical production for rapid identification of sorghum types and adulterations.

Comprehensive evaluation of nutritional components, bioactive metabolites, and antioxidant activities in diverse sorghum (Sorghum bicolor (L.) Moench) landraces

Sorghum, one of the prospective crops for addressing future food and nutrition security, has received attention in recent years due to its health-promoting compounds. It is known that several environmental and genetic factors affect the metabolite contents of dietary crops. This study investigated the diversity of different nutrients, functional metabolites, and antioxidant activity using three different assays in 53 sorghum landraces from Korea, China, Japan, Ethiopia, and South Africa. The effects of origin and seed color variations were also investigated. Total phenolic (TPC), total tannin (TTC), total fat, total protein, total dietary fiber, and total crude fiber contents all varied significantly among the sorghum landraces (p < 0.05). Using a gas chromatography-flame ionization detector, palmitic, stearic, oleic, linoleic, and linolenic acids were detected in all the sorghum landraces, and their content significantly varied (p < 0.05). Furthermore, four 3-deoxyanthocyanidins (luteolinidin, apigeninidin, 5-methoxyluteolinidin, and 7-methoxyapigeninidin) and two flavonoids (luteolin and apigenin) were detected in most of the landraces using liquid chromatography-tandem mass spectrometry, and their concentrations also significantly varied. Statistical analyses supported by multivariate tools demonstrated that seed color variation had a significant effect on TPC, TTC, DPPH• and ABTS•+ scavenging activities, and ferric-reducing antioxidant power, with yellow landraces having the highest and white landraces having the lowest values. Seed color variation also had a significant effect on dietary fiber, linoleic acid, linolenic acid, and luteolin contents. In contrast, all nutritional components and fatty acids except total protein and oleic acid were significantly affected by origin, while most 3-deoxyanthocyanidins and flavonoids were unaffected by both origin and seed color differences. This is the first study to report the effect of origin on sorghum seed metabolites and antioxidant activities, laying the groundwork for future studies. Moreover, this study identified superior landraces that could be good sources of health-promoting metabolites.

Antioxidant activities, phenolic compounds, and mineral composition of seed from Acacia retinodes, A. Provincialis and A. Tenuissima

Seeds of the species Acacia retinodes, A. provincialis, and A. tenuissima) from different growing locations were analysed for their mineral composition, free and bound polyphenols, and flavonoids. Previous research has studied these compounds in only a limited number of Acacia species, and only one study reports significant differences between three species. All species were rich in potassium (353 - 427 mg/100 g), sodium (14 - 240 mg/100 g) and iron (7 - 8 mg/100 g). The free polyphenol extracts of all species had higher total phenolic content, total flavonoid content and antioxidant activities than their bound counterparts, indicating the possibility of higher bioavailability than the bound polyphenol extracts. The predominant phenolic compounds found in the Acacia polyphenol seed extracts were 6-Hydroxy-2-methylindole and 2,2'-Methylenebis(6-tert-butyl-methylphenol), though no phenolic compounds were identified in the bound extracts of A. retinodes Grampians and A. provincialis Tarrington. Other compounds identified in the seed extracts include sucrose, d-fructofuranose and d-pinitol.

Exploring the potentials of sorghum genotypes: a comprehensive study on nutritional qualities, functional metabolites, and antioxidant capacities

Introduction

Sorghum, long regarded as one of the most underutilized crops, has received attention in recent years. As a result, conducting multidisciplinary studies on the potential and health benefits of sorghum resources is vital if they are to be fully exploited. In this study, the nutritional contents, functional metabolites, and antioxidant capacities of 23 sorghum breeding lines and three popular cultivars were assessed.

Materials and method

All of the sorghum genotypes were grown under the same conditions, and mature seeds were hand-harvested. The metabolite contents and antioxidant capacities of sorghum seeds were assessed using standard protocols. Fatty acids were quantified using a gas chromatography-flame ionization detector, whereas flavonoids and 3-deoxyanthocyanidins were analyzed using a liquid chromatography-tandem mass spectrometry method. The data were analyzed using both univariate and multivariate statistical approaches.

Results and discussion

Total protein (9.05-14.61%), total fat (2.99-6.91%), crude fiber (0.71-2.62%), dietary fiber (6.72-16.27%), total phenolic (0.92-10.38 mg GAE/g), and total tannin (0.68-434.22 mg CE/g) contents varied significantly across the sorghum genotypes (p < 0.05). Antioxidant capacity, measured using three assays, also differed significantly. Five fatty acids, including palmitic, stearic, oleic, linoleic, and linolenic acids, were found in all the sorghum genotypes with statistically different contents (p < 0.05). Furthermore, the majority of the sorghum genotypes contained four 3-deoxyanthocyanidins, including luteolinidin, apigeninidin, 5-methoxyluteolinidin, and 7-methoxyapigeninidin, as well as two dominant flavonoids, luteolin and apigenin. Compared to the cultivars, some breeding lines had significantly high levels of metabolites and antioxidant activities. On the other hand, statistical analysis showed that total tannin, total phenolic, and antioxidant capacities varied significantly across white, yellow, and orange genotypes. Principal component analysis was used to differentiate the sorghum genotypes based on seed color and antioxidant index levels. Pearson's correlation analysis revealed strong links between biosynthetically related metabolites and those with synergistic antioxidant properties.

Conclusion

This research demonstrated the diversity of the sorghum resources investigated. Those genotypes with high levels of nutritional components, functional metabolites, and antioxidant activities could be used for consumption and breeding programs.

Chemical Composition, Antioxidant Potential, and Nutritional Evaluation of Cultivated Sorghum Grains: A Combined Experimental, Theoretical, and Multivariate Analysis

Sorghum grain (Sorghum bicolor L. Moench) is a gluten-free cereal with excellent nutritional value and is a good source of antioxidants, including polyphenols, as well as minerals with proven health benefits. Herein, the phenolic composition, elemental profile, and antioxidant activity of sixteen food-grade sorghum grains (S1-S16) grown under agroecological conditions in Serbia were determined. Nine phenolic compounds characteristic of sorghum grains, such as luteolinidin, 5-methoxyluteolinidin, luteolidin derivative, luteolidin glucoside, apigeninidin, 7-methoxyapigeninidin, apigeninidin glucoside, and cyanidin derivative, were quantified. The antioxidant potential of the analyzed sorghum grains was evaluated by UV/Vis (DPPH, ABTS, and FRAP) and Electron Paramagnetic Resonance spectroscopy (hydroxyl and ascorbyl radical scavenging assays). The content of macro- and microelements was determined by Inductively Coupled Plasma Optical Emission spectroscopy. Theoretical daily intakes of selected major and trace elements were assessed and compared with the Recommended Daily Allowance or Adequate Intake. Sample S8 had the highest amount of phenolic compounds, while S4, S6, and S8 exhibited the strongest antioxidative potential. The sorghum studied could completely satisfy the daily needs of macro- (K, Mg, and P) and microelements (Se, Zn, Fe). Pattern recognition techniques confirmed the discrimination of samples based on phenolic profile and elemental analysis and recognized the main markers responsible for differences between the investigated samples. The reaction between hydroxyl radicals and luteolinidin/apigeninidin was investigated by Density Functional Theory and thermodynamically preferred mechanism was determined.

Effect of Milling on Nutritional Components in Common and Zinc-Biofortified Wheat

Biofortification is one of the most successful approaches to enhance the level of micronutrients in wheat. In the present study, wheats with zinc biofortification (foliar fertilization and breeding strategies) were milled into five components (whole flour, break flour, reduction flour, fine bran, and coarse bran) and their mineral content and nutritional components were evaluated. The results revealed that biofortification greatly increased the Zn concentration (by 30.58%-30.86%) and soluble Zn content (by 28.57%-42.86%) of whole flour after digestion. This improvement is mainly in break flour, reduction flour, and fine bran. Meanwhile, the contents of macronutrients including ash, lipids, and proteins and micronutrients containing iron, calcium, and vitamins (B₁, B₆, and B₉) increased after biofortification. In addition, there was a decline in the concentrations of vitamins B₂ and B₅. Although dietary fibers and starch are the major carbohydrates, total dietary fiber exhibited a declining trend in coarse bran, and starch exhibited a rising trend in break and reduction flour. There was a decrease in the molar ratio of phytates: zinc did not promote a significant improvement in zinc bioaccessibility. These results can be useful for generating wheat varieties rich in micronutrients as well as having better nutritional traits.

Characterisation of Polishing Frequency for Three Varieties of Sorghum Grain in Java, Indonesia

To determine the suitability of different sorghum cultivars (grown in Indonesia) for the manufacturing of acceptable food products, their properties must first be characterised. During sorghum processing, polishing may affect the final nutritional value and quality of the product. This study is aimed at determining the effects of sorghum variety and polishing frequency on nutritional value. This was achieved by using a factorial randomised block design with two factors: sorghum variety (Bioguma, Numbu, and Super) and polishing frequency (once, twice, or thrice). Tannin content, antioxidant capacity, levels of dietary fibre and resistant starch, and fat, ash, and carbohydrate content varied according to sorghum cultivar. Compared to other sorghum varieties, the Super cultivar contained the highest levels of antioxidants, dietary fibre, fat content, protein, resistant starch, and tannins (although high tannin content could be lowered by polishing grains up to three times). The frequency of polishing affected tannin and ash levels in all three sorghum varieties. Polishing frequency also affected the antioxidant capacity of polished sorghum grains. The findings from this study should be considered when determining appropriate applications for various sorghum-based food products.

The Effect of High Pressure Processing on Textural, Bioactive and Digestibility Properties of Cooked Kimberley Large Kabuli Chickpeas

High pressure processing is a non-thermal method for preservation of various foods while retaining nutritional value and can be utilized for the development of ready-to-eat products. This original research investigated the effects of high pressure processing for development of a ready-to eat chickpea product using Australian kabuli chickpeas. Three pressure levels (200, 400, and 600 MPA) and two treatment times (1 and 5 min) were selected to provide six distinct samples. When compared to the conventionally cooked chickpeas, high pressure processed chickpeas had a more desirable texture due to decrease in firmness, chewiness, and gumminess. The general nutrient composition and individual mineral content were not affected by high pressure processing, however, a significant increase in the slowly digestible starch from 50.53 to 60.92 g/100 g starch and a concomitant decrease in rapidly digestible starch (11.10-8.73 g/100 g starch) as well as resistant starch (50.53-30.35 g/100 g starch) content was observed. Increased starch digestibility due to high pressure processing was recorded, whereas in vitro protein digestibility was unaffected. Significant effects of high pressure processing on the polyphenol content and antioxidant activities (DPPH, ABTS and ORAC) were observed, with the sample treated at the highest pressure for the longest duration (600 MPa, 5 min) showing the lowest values. These findings suggest that high pressure processing could be utilized to produce a functional, ready to eat kabuli chickpea product with increased levels of beneficial slowly digestible starch.

Taxifolin and Sorghum Ethanol Extract Protect against Hepatic Insulin Resistance via the miR-195/IRS1/PI3K/AKT and AMPK Signalling Pathways

This study aimed to evaluate the effects of taxifolin and sorghum ethanol extract on free fatty acid (FFA)-induced hepatic insulin resistance. FFA treatment decreased glucose uptake by 16.2% compared with that in the control, whereas taxifolin and sorghum ethanol extract increased the glucose uptake. Additionally, taxifolin and sorghum ethanol extract increased the expression of p-PI3K, p-IRS1, p-AKT, p-AMPK, and p-ACC in FFA-induced hepatocytes. Furthermore, FFA treatment increased the expression of miR-195. However, compared with the FFA treatment, treatment with taxifolin and sorghum ethanol extract decreased miR-195 expression in a dose-dependent manner. Taxifolin and sorghum ethanol extract enhanced p-IRS1, p-PI3K, p-AMPK, p-AKT, and p-ACC expression by suppressing miR-195 levels in miR-195 mimic- or inhibitor-transfected cells. These results indicate that taxifolin and sorghum ethanol extract attenuate insulin resistance by regulating miR-195 expression, which suggests that taxifolin and sorghum ethanol extract may be useful antidiabetic agents.

Changes in the root-associated bacteria of sorghum are driven by the combined effects of salt and sorghum development

BACKGROUND

Sorghum is an important food staple in the developing world, with the capacity to grow under severe conditions such as salinity, drought, and a limited nutrient supply. As a serious environmental stress, soil salinization can change the composition of rhizosphere soil bacterial communities and induce a series of harm to crops. And the change of rhizospheric microbes play an important role in the response of plants to salt stress. However, the effect of salt stress on the root bacteria of sorghum and interactions between bacteria and sorghum remains poorly understood.

RESULTS

The purpose of this study was to assess the effect of salt stress on sorghum growth performance and rhizosphere bacterial community structure. Statistical analysis confirmed that low high concentration stress depressed sorghum growth. Further taxonomic analysis revealed that the bacterial community predominantly consisted of phyla Proteobacteria, Actinobacteria, Acidobacteria, Chloroflexi, Bacteroidetes and Firmicutes in sorghum rhizosphere soil. Low salt stress suppressed the development of bacterial diversity less than high salt stress in both bulk soil and planted sorghum soil. Different sorghum development stages in soils with different salt concentrations enriched distinctly different members of the root bacteria. No obviously different effect on bacterial diversity were tested by PERMANOVA analysis between different varieties, but interactions between salt and growth and between salt and variety were detected. The roots of sorghum exuded phenolic compounds that differed among the different varieties and had a significant relationship with rhizospheric bacterial diversity. These results demonstrated that salt and sorghum planting play important roles in restructuring the bacteria in rhizospheric soil. Salinity and sorghum variety interacted to affect bacterial diversity.

CONCLUSIONS

In this paper, we found that salt variability and planting are key factors in shifting bacterial diversity and community. In comparison to bulk soils, soils under planting sorghum with different salt stress levels had a characteristic bacterial environment. Salinity and sorghum variety interacted to affect bacterial diversity. Different sorghum variety with different salt tolerance levels had different responses to salt stress by regulating root exudation. Soil bacterial community responses to salinity and exotic plants could potentially impact the microenvironment to help plants overcome external stressors and promote sorghum growth. While this study observed bacterial responses to combined effects of salt and sorghum development, future studies are needed to understand the interaction among bacteria communities, salinity, and sorghum growth.

Comparison of quercetin and rutin inhibitory influence on Tartary buckwheat starch digestion in vitro and their differences in binding sites with the digestive enzyme

Inhibitory effects of flavonoids on starch digestibility were well known, but the structural mechanism was not clear. This study was focused on the diverse effect of quercetin and rutin on digestibility of Tartary buckwheat starch. Results showed that quercetin and rutin reduced the starch digestion by altering starch structure in bound forms and inhibiting digestive enzyme activity in free forms simultaneously, and quercetin showed a stronger effect than rutin. Molecular docking and saturation transfer difference-nuclear magnetic resonance (STD-NMR) revealed different binding site of rutin from quercetin was due to its hydroxyl and hydrogen on the glycoside structure. Rutin interacted with enzymes mainly by CH and OH on the glycoside structure which induced steric hindrance and restricted the inhibitory effect of quercetin fraction. The glycoside structure weakened inhibition of rutin on digestive enzymes in free forms rather than influence its anti-digestive effects in bound forms with starch.

Bioaccessibility and Bioactivity of Cereal Polyphenols: A Review

Cereal bioactive compounds, especially polyphenols, are known to possess a wide range of disease preventive properties that are attributed to their antioxidant and anti-inflammatory activity. However, due to their low plasma concentrations after oral intake, there is controversy regarding their therapeutic benefits in vivo. Within the gastrointestinal tract, some cereal polyphenols are absorbed in the small intestine, with the majority accumulating and metabolised by the colonic microbiota. Chemical and enzymatic processes occurring during gastrointestinal digestion modulate the bioactivity and bioaccessibility of phenolic compounds. The interactions between the cereal polyphenols and the intestinal epithelium allow the modulation of intestinal barrier function through antioxidant, anti-inflammatory activity and mucin production thereby improving intestinal health. The intestinal microbiota is believed to have a reciprocal interaction with polyphenols, wherein the microbiome produces bioactive and bioaccessible phenolic metabolites and the phenolic compound, in turn, modifies the microbiome composition favourably. Thus, the microbiome presents a key link between polyphenol consumption and the health benefits observed in metabolic conditions in numerous studies. This review will explore the therapeutic value of cereal polyphenols in conjunction with their bioaccessibility, impact on intestinal barrier function and interaction with the microbiome coupled with plasma anti-inflammatory effects.

Sorghum under saline conditions: responses, tolerance mechanisms, and management strategies

An overview is presented of recent advances in our knowledge of responses and mechanisms rendering adaptation to saline conditions in sorghum. Different strategies deployed to enhance salinity stress tolerance in sorghum are also pointed out. Salinity stress is a growing problem worldwide. Sorghum is the fifth key crop among cereals. Understanding responses and tolerance strategies in sorghum would be therefore helpful effort for providing biomarkers for designing greatest salinity-tolerant sorghum genotypes. When sorghum exposed to salinity, salinity-tolerant genotypes most probably reprogram their gene expression to activate adaptive biochemical and physiological responses for survival. The review thus discusses the possible physiological and biochemical responses that confer salinity tolerance to sorghum under saline conditions. Although it is not characterized in sorghum, salinity perceiving and transmitting signals to downstream responses via signaling transduction pathways most likely are essential strategy for sorghum adaptation to salinity stress. Sorghum has also shown to withstand moderate saline environments and retain the germination, growth, and photosynthetic activities. Salinity-tolerant sorghum genotypes show the ability to exclude excessive Na⁺ from reaching shoots and induce ion homeostasis. Osmotic homeostasis and ROS detoxification are also evident as salinity tolerance strategies in sorghum. These above mechanisms lead to re-establishment of cellular ionic, osmotic, and redox homeostasis as well as photosynthesis efficiency. It is noteworthy that these mechanisms act individually or co-operatively to minimize the salinity hazards and enhance acclimation in sorghum. We conclude, however, that although these responses contribute to sorghum tolerance to salinity stress, they seem to be not adequate at higher concentrations of salinity, which agrees with sorghum ranking as moderately salinity-tolerant crop. Also, some of these tolerance strategies reported in other crops are not well studied and documented in sorghum, but most probably have roles in sorghum. Further improvement in sorghum salinity tolerance using different approaches is definitely necessary to meet the requirements of its harsh production environments, and therefore, these approaches are addressed.

Comparative Study on Seed Characteristics, Antioxidant Activity, and Total Phenolic and Flavonoid Contents in Accessions of Sorghum bicolor (L.) Moench

Sorghum is a major cereal food worldwide, and is considered a potential source of minerals and bioactive compounds. Its wide adaptive range may cause variations in its agronomic traits, antioxidant properties, and phytochemical content. This extensive study investigated variations in seed characteristics, antioxidant properties, and total phenolic (TPC) and flavonoid contents (TFC) of sorghum collected from different ecological regions of 15 countries. The antioxidant potential of the seed extracts of various sorghum accessions was determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azinobis 3-ethylbenzothiazoline-6-sulfonate (ABTS) radical scavenging assays. Significant variations in TPC were observed among the sorghum accessions. All 78 sorghum accessions used in this study exhibited significant variations in TFC, with the lowest and highest amount observed in accessions C465 and J542, respectively. DPPH scavenging potential of the seed extracts for all the accessions ranged from 11.91 ± 4.83 to 1343.90 ± 81.02 µg mL⁻¹. The ABTS assay results were similar to those of DPPH but showed some differences in the accessions. Pearson’s correlation analysis revealed a wide variation range in the correlation between antioxidant activity and TPC, as well as TFC, among the sorghum accessions. A wide diversity range was also recorded for the seed characteristics (1000-seed weight and seed germination rate). A dendrogram generated from UPGMA clustering, based on seed traits, antioxidant activity, TPC, and TFC was highly dispersed for these accessions. Variations among the accessions may provide useful information regarding the phytoconstituents, antioxidant properties, and phytochemical contents of sorghum and aid in designing breeding programs to obtain sorghum with improved agronomic traits and bioactive properties.

Effect of extrusion technology on hempseed (Cannabis sativa L.) oil cake: Polyphenol profile and biological activities

Effects of extrusion with varying barrel temperature, moisture content, and screw speed on hempseed oil cake were studied for the first time. Extrusion at lower moisture (30%) and higher screw speed (300 rpm) significantly increased the proportion of free polyphenols, flavonoids, and phenylpropionamide content, and α -glucosidase and acetylcholinesterase inhibition activities. Full factorial design confirmed the three-way interactions among all extrusion parameters for all chemical assays with the bound phenolic fraction, total flavonoid content, and DPPH inhibition activity of the free phenolic fraction. HPLC-DAD-ESI-QTOF-MS/MS analysis tentatively identified 26 phenylpropionamides, and the contents of N-trans-caffeoyltyramine (66.26 µg/g) and total phenylpropionamides (85.77 µg/g) were significantly increased after extrusion at the lower moisture and higher screw speed extrusion conditions. The higher α -glucosidase inhibition activity at higher screw speed could be due to the N-trans-caffeoyltyramine (r = 0.99, p < 0.01), while the AChE inhibition activity appeared to be influenced more by the cannabisins A-C, M (r > 0.8, p < 0.01). PRACTICAL APPLICATION: Hempseed oil cake is a byproduct of oil extraction, with high protein and high fiber contents. The results of this research could be used directly in food industry to improve the nutritional and commercial value of hempseed oil cake by extrusion technology.

Effect of irrigation, fertiliser type and variety on grain yield and nutritional quality of spelt wheat (Triticum spelta) grown under semi-arid conditions

Previous studies reported higher antioxidant and mineral micronutrient concentrations in organic compared to conventional wheat flour, but the reasons are poorly understood. Here we report results from a long-term, factorial field experiment designed to assess effects of variety choice, supplementary irrigation and contrasting fertilization regimes used in organic and conventional production on the nutritional quality and yield of spelt wheat grown in a semi-arid environment. Long-straw (Oberkulmer, Rubiota, ZOR) varieties had 10-40% higher grain Cu, Fe, Mn and Zn concentrations, while the modern, short straw variety Filderstolz had 15-38% higher grain antioxidant activity. Supplementary irrigation and the use of manure instead of mineral NPK as fertilizer had no substantial effect on the nutritional composition of spelt grain, but increased grain yields by ~ 150 and ~ 18% respectively. Overall, this suggests that breeding/variety selection is the most promising approach to improve the nutritional quality of spelt grain in semi-arid production environments.

Characterizing the volatile compounds of different sorghum cultivars by both GC-MS and HS-GC-IMS

The current study applied both GC-MS and GC-IMS for characterizing the volatile compounds of six Australian sorghum cultivars. For raw sorghum, the result of GC-MS showed that the ester compounds were abundant in six raw samples. Among these esters, the content of hexadecanoic acid ethyl ester was highest in all of the raw samples. Compound 3-octanone only existed in Apollo, Bazley and Liberty, and 2-undecanone was found to be in MR43. The result of GC-IMS showed that the signals of benzaldehyde, 2,3-butanedione were generally noted in the six raw samples. In general, The Apollo and Buster had more volatile compounds, followed by Bazley and Liberty. In contrast, MR43 and G44 had the least volatile compounds. For cooked sorghums, more fatty aldehydes are formed compared to its corresponding raw sample, in which the current data indicated that 40 volatile compounds were identified by GC-MS, and 11 of them were identified as the key aroma compounds (OAVs > 1). More important, the variation in the compounds of hexanal, heptanal, octanal, 2-heptenal, nonanal, trans- 2-octenal, benzeneaceldehyde, (E)-2-nonenal, 1-octen-3-ol, 1-pentanol, 2-methoxy-4-vinylphenol and 2-pentylfuran might be applied for explaining the aroma characteristics among the six sorghum cultivars. The result of GC-IMS showed that 26 volatile compounds but not in the results from GC-MS detection, indicating the advantage of the methodology combination for a better understanding the impact of cultivars and cooking on volatile characteristics of the sorghums.

Sorghum (Sorghum bicolor L.) as a potential source of bioactive substances and their biological properties

Sorghum is the fifth cereal most produced in the world after wheat, rice, maize, and barley. In some regions, this crop is replacing maize, due to its high yield, resistance to drought and heat. There are several varieties of sorghum, whose coloration varies from cream, lemon-yellow, red, and even black. Pigmented sorghum grain is a rich source of antioxidants like polyphenols, mainly tannins, which have multiple benefits on human health such as, antiproliferative properties associated with the prevention of certain cancers, antioxidant activities related to the prevention of associated diseases to oxidative stress, antimicrobial and anti-inflammatory effects, it also improves glucose metabolism. Despite having these types of compounds, it is not possible to assimilate them, their use in the food industry has been limited, since sorghum is considered a food of low nutritional value, due to the presence of anti-nutritional factors such as strong tannins which form complexes with proteins and iron, thus reducing their digestibility. Based on these restrictions that this product has had as food for humans, the analysis of this review emphasizes the valorization of sorghum as a source of bioactive substances and the importance they confer on human health because of the biological potential it has.

Extrusion improves the phenolic profile and biological activities of hempseed (Cannabis sativa L.) hull

The impact of extrusion at different barrel temperature and screw speed on the hempseed hull was investigated. The extrusion treatments showed significant (p < 0.05) increase in total phenolic content, proportion of free phenolic compounds, and DPPH and ABTS radical scavenging activities. At low screw speed (150 rpm), significantly (p < 0.05) higher α-glucosidase and acetylcholinesterase inhibition activities were observed in the extruded samples. The full factorial model revealed a significant interaction between extrusion parameters on total phenolic/flavonoid content and antioxidant activities for free fraction, and α-glucosidase and acetylcholinesterase inhibition for whole fraction. A total of 26 phenylpropionamides, including hydroxycinnamic acid amides and lignanamides, were identified by HPLC-ESI-QTOF-MS/MS. HPLC-DAD analysis showed a 25-78% increase in total phenylpropionamide content in hempseed hull after extrusion. Pearson's correlation displayed significant (p < 0.05) positive correlation of N-trans-caffeoyltyramine, the most abundant phenylpropionamide, with all biological activities (r = 0.832-0.940).

The bioactive compounds and cellular antioxidant activity of Herbaceous peony (Paeonia lactiflora Pall) seed oil from China

Herbaceous peony (HP) seed oil has been consumed in some regions of China, yet little information is available on its bioactive composition and antioxidant activity. This study aimed to evaluate the fatty acid compositions, micronutrients contents, and cellular antioxidant activity (CAA) of HP seed oil from five varieties. Results indicated that this oil had high percentages of monounsaturated (32.15 to 45.92%) and polyunsaturated fatty acids (58.65 to 61.95%), and the α-linolenic acid C18:3 was the highest in Fushao seed oil. Additionally, the high concentrations of tocopherol and phytosterol were found in all seed oils, and 10 individual polyphenols have been evaluated. Fushao seed oil had the highest polyphenols levels and showed higher CAA values. Both hierarchical cluster analysis and principal component analysis have been used to distinguish HP seed oil from different varieties. This information is valuable for the nutritional value and industrial interest of HP seed oil in China. PRACTICAL APPLICATION: This research showed that Herbaceous peony seed oil had higher levels of minor components and polyunsaturated fatty acids, especially, α-linolenic acid, and our results could also provide the theoretical foundation for the health benefits of Herbaceous peony seed oil as the vegetable oils. However, the variety of Herbaceous should be considered when extracting oil from Herbaceous peony seeds in the industry.

Comprehensive profiling of phenolic compounds by HPLC-DAD-ESI-QTOF-MS/MS to reveal their location and form of presence in different sorghum grain genotypes

In this study, comprehensive profiling of the phenolic compounds in sorghum grain was achieved by analysing the free and bound extracts of sorghum bran and kernel fractions from five Australian sorghum genotypes (1 white, 2 red, 1 brown and 1 black coloured), using HPLC-DAD-ESI-QTOF-MS/MS. A total of 110 phenolic compounds were annotated, out of which 56 were reported for the first time in sorghum grain. Compounds with matched authentic standards were quantified/semi-quantified. Multiple factor analysis (MFA) was performed and heatmaps generated, which provided direct visualisation of the distribution of individual phenolic compounds/subclasses between the sorghum samples. The results indicated that phenolic compounds were concentrated on the bran, and free and bound extracts had different phenolic composition. The phenolic compound/subclass profile varied greatly among sorghum genotypes. Brown sorghum genotype (IS131C) had the highest concentration of total phenolic contents, and the bran fraction of brown sorghum had the most abundant and diverse phenolic composition among all tested samples. This study provides the most comprehensive phenolic profile of Australian representative sorghum grains up to date.

Diverse effects of rutin and quercetin on the pasting, rheological and structural properties of Tartary buckwheat starch

We investigated the interactions of two main phenolics, rutin and quercetin, with starch, the primary component of Tartary buckwheat. The addition of rutin or quercetin significantly affected the structural and physicochemical properties of the starch, and rutin showed a stronger effect than quercetin, particularly at a dose of 6% (w/w). Rutin better enhanced the aggregation of starch pastes and gel formation than quercetin according to our pasting, rheological and thermal property analyses. A scanning electron microscopy analysis of its morphology showed that rutin was more easily dispersed in starchy matrix than quercetin and acted as rigid fillers for gels. The nuclear magnetic resonance results showed different binding sites due to the steric hindrance of the rutin disaccharide groups (rutinose). These findings provide fundamental information about applying rutin during the whole grain processing of Tartary buckwheat.

Plant polyphenols Morin and Quercetin rescue nitric oxide production in diabetic mouse aorta through distinct pathways

Diabetic vascular complications are associated with endothelial dysfunction. Various plant-derived polyphenols benefit cardiovascular function by protecting endothelial nitric oxide (NO) production through as yet unclear mechanisms. This study compared the effects of two structurally similar polyphenols, Morin (MO) and Quercetin (QU), on endothelial function in isolated aorta from control and streptozotocin (STZ)-induced diabetic mice. Vascular function under treatment with MO, QU, and various signaling pathway modulators was measured by isometric tension in an organ bath system, NO production by chemical assay and HPLC, and changes in protein signaling factor expression or activity by western blotting (WB). Both polyphenols acted as potent vasodilators and this effect was associated with increased phosphorylation of Akt and endothelial NO synthase (eNOS). An Akt inhibitor blocked MO- and QU-induced vasorelaxation as well as Akt phosphorylation. However, inhibitors of phosphoinositide 3-kinase (PI3K) and AMP-activated protein kinase (AMPK) suppressed only QU-induced vasorelaxation, NO production, and AMPK phosphorylation. These results suggested that plant polyphenols MO and QU both promote eNOS-mediated NO production and vasodilation in diabetic aorta, MO via Akt pathway activation and QU via PI3K/Akt and AMPK pathway activation. Elucidation of these pathways may define effective therapeutic targets for diabetic vascular dysfunction.

Flavonoids in Decorticated Sorghum Grains Exert Antioxidant, Antidiabetic and Antiobesity Activities

Eight new genotypes of brown sorghum grain were decorticated and assessed for their antioxidant, antidiabetic and antiobesity activities in vitro. The DPPH and ABTS radical scavenging assays of the soluble fractions were evaluated, followed by digestive enzymes and advanced glycation end-products (AGEs) formation inhibition assays. DSOR 33 and DSOR 11 exhibited the highest DPPH (IC50 = 236.0 ± 1.98 µg/mL and 292.05 ± 2.19 µg/mL, respectively) and ABTS radical scavenging activity (IC50 = 302.50 ± 1.84 µg/mL and 317.05 ± 1.06 µg/mL, respectively). DSOR 17, DSOR 11 and DSOR 33 showed significantly higher inhibitory activity of both α-glucosidase and α-amylase (IC50 = 31.86, 35.10 and 49.40 µg/mL; and 15.87, 22.79 and 37.66 µg/mL, respectively) compared to acarbose (IC50 = 59.34 and 27.73 µg/mL, respectively). Similarly, DSOR 33, DSOR 11 and DSOR 17 showed potent inhibition of both AGEs and lipase with IC50 values of 18.25, 19.03 and 38.70 µg/mL; and 5.01, 5.09 and 4.94 µg/mL, respectively, compared to aminoguanidine (52.30 µg/mL) and orlistat (5.82 µg/mL). Flavonoids were the predominant compounds identified, with flavones being the major subclass in these three extracts. Our findings suggest that decorticated sorghum grains contain substantial amounts of flavonoids and could be promising candidates for the prevention and treatment of diabetes and obesity.

Comparison of the phenolic contents, antioxidant activity and volatile compounds of different sorghum varieties during tea processing

BACKGROUND

Sorghum grain is rich in phenolic compounds and has the potential to be developed into functional beverages such as sorghum grain tea, in which the health benefits and flavour are the important quality attributes to be considered in tea product development. Therefore, this study investigated the effect of grain tea processing steps on the phenolic contents, antioxidant activity and aroma profile (volatile compounds) of MR-Buster (red-coloured) and Shawaya Short Black 1 (black-coloured) sorghum and the results compared with those for our previously reported Liberty (white-coloured) sorghum.

RESULTS

Tea processing had significant impacts on sorghum polyphenols and volatile compounds, but the effect and level varied among sorghum varieties. The phenolic contents and antioxidant activity in these three sorghum varieties were consistent in both raw grain and grain tea samples and in the order Shawaya Short Black 1 > MR-Buster > Liberty. However, the volatile profiles (both individual and grouped volatiles) were significantly different between sorghum varieties, and the abundance and diversity of the volatile compounds of the tea samples were in the order Liberty > MR-Buster > Shawaya Short Black 1.

CONCLUSIONS

Black-coloured sorghum with high phenolic content and antioxidant activity is more suitable for making sorghum tea considering the health benefits. In terms of the aroma intensity and diversity, white-coloured sorghum could be the ideal material. However, future study is needed to determine the key volatile compounds that positively contribute to the aroma. This work provides important insights into the selection of grain materials for sorghum grain tea production. © 2019 Society of Chemical Industry.

Microencapsulation of Red Sorghum Phenolic Compounds with Esterified Sorghum Starch as Encapsulant Materials by Spray Drying

Phenolic compounds with antioxidant properties are highly sensitive molecules, which limits their application. In response, extruded esterified starch has been proposed as efficient encapsulating material. In this work, we aim to describe the encapsulation of red sorghum phenolic compounds by spray drying using extruded phosphorylated, acetylated and double esterified sorghum starch as wall material. Their respective encapsulation yields were 77.4, 67.4 and 56.8%, and encapsulation efficiency 91.4, 89.7 and 84.6%. Degree of substitution confirmed esterification of the sorghum starch and Fourier transform infrared spectroscopy showed the significant chemical and structural changes in the extruded esterified starch loaded with phenolic compounds. Microcapsules from phosphorylated sorghum starch showed the highest endothermic transition (173.89 °C) and provided a greater protection of the phenolic compounds during storage at 60 °C for 35 days than the other wall materials. Extruded esterified sorghum starch proved to be effective material for the protection of phenolic compounds due to its high encapsulation efficiency and stability during storage.