Antioxidant Capacity and Profiles of Phenolic Acids in Various Genotypes of Purple Wheat

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.

A Functional Flatbread (Bazlama): High in Beta-Glucan and Plant-Based Protein Content

This study focused on developing a functional bazlama with a lower glycemic index (GI) that is high in β-glucan and rich in plant-based protein. Functional bazlama samples were produced by supplementing bread wheat flour with high β-glucan content hull-less barley flour and high protein content lentil flour (15%, 30%, and 45%). Additionally, mixed bazlama samples (Mix1, Mix2, Mix3, and Mix4) were produced by supplementing them with both barley and lentil flours. The results showed that 3 g of β-glucan could be provided from the bazlama sample and supplemented with 45% barley flour, which meets the threshold to carry health claims. Supplementing with 30% and 45% lentil flour increased the protein content of the bazlama samples to a level qualifying them as a "high protein". The control bazlama had a high GI, while samples supplemented with 30% and 45% barley or lentil flour and all mixed bazlama samples had medium GI values, and Mix2 had the lowest GI value among all bazlama samples. Also, as the supplementation levels of barley and lentil flour increased, the phenolic contents and antioxidant capacities of the bazlama samples increased. The results of the present study indicate that barley and lentils can be used as an ingredient in traditional flatbreads to obtain products with better functional and nutritional properties.

Investigation of Phenolic Composition and Antioxidant Capacities in Selected Turkish Indigenous Wheat Varieties

Indigenous wheat varieties continue to be cultivated and preserved due to their climatic adaptability and distinctive flavor contributions to cultural cuisines. This study covers the research gap by investigating the natural bioactive and antioxidant compounds present in Turkish indigenous wheat varieties. To this aim, the phenolic composition, ash contents, and antioxidant capacity were investigated in eighteen different indigenous Turkish wheat varieties (4 monococcum, 3 dicoccum, 4 durum, and 7 aestivum genotypes). An overall comprehensive analysis was carried out using statistical tools such as Heatmap and PCA (Principal component analysis). The results indicated that dicoccum genotype exhibited highest soluble free (49.04 mg) and soluble conjugated phenolics (188.54 mg), whereas aestivum was found rich in insoluble bound (873.89 mg), total phenolic (1058.35 mg GAE/kg dm), and total flavonoid (380.43 mg CE/kg dm) contents. Moreover, monococcum, dicoccum, and durum genotypes exhibited non-significantly higher total antioxidant capacities compared to the aestivum wheat genotype. In conclusion, indigenous wheat varieties, particularly from the dicoccum and aestivum genotypes, have the potential to be a significant source of phenolic and antioxidant compounds. These findings suggest promising prospects for the selection of indigenous wheat varieties under on-farm conservation programs for future commercialization and breeding programs.

Hybrid Modification of Wheat Bran Using Microbial Processing and Ultrasound: Enhancements in Bran Composition and Bread Quality

This study investigates the effects of microbial bioprocessing (MB), ultrasound treatment (UT), and their combined application (hybrid method, HM) on the functional and nutritional enhancement of wheat bran (WB) and its impact on bread quality. MB was performed by using Saccharomyces cerevisiae with Levilactobacillus brevis LABE 32 (MB32) and Lactiplantibacillus plantarum LABE 29 (MB29). MB32 significantly increased soluble dietary fiber (SDF) and reduced phytic acid content by up to 25.7% when compared to the control. UT further decreased phytic acid content by 52.2% and enhanced phenolic compound release, contributing to improved antioxidant activity. The hybrid method (HM) demonstrated the strongest effect, reducing phytic acid content by 95% and enhancing antioxidant properties, including a 2.4-fold increase in bound antioxidant activity (bound-AA). Bread produced from modified WB showed improvements in specific volume (SV), texture, and nutritional composition. The HM-treated WB yielded bread with the highest SV, approximately 10% greater than the control, while MB29 produced significantly harder bread than other samples (p < 0.05). The HM-treated bread had the highest crust L* value and softest texture (p < 0.05). Nutritionally, only UT and HM treatments significantly increased the total dietary fiber (TDF) content, with the most pronounced increase observed in the HM treatment. Phytic acid degradation in the WB modified with MB32 and UT was in accordance with their breads, notably lowering phytic acid content. Additionally, MB32 and HM increased total phenolic content (TPC) and antioxidant activity, enhancing the bread's overall nutritional quality. In conclusion, the hybrid application of MB and UT (HM) proved to be the most effective in improving the functional and nutritional properties of WB and the resulting bread, including increased dietary fiber content, reduced phytic acid levels, and enhanced antioxidant activity.

xAgrotriticum spp.: Quality properties of a potential perennial cereal candidate for sustainable agriculture

Perennial crop species have gained greater importance with regard to agricultural sustainability because of the ecological concerns related to annual crops. This study aimed to determine some of the primary quality traits of xAgrotriticum grains, a potential perennial wheat genotype, in comparison to the annual bread wheat variety Fineway. The antioxidant activity of xAgrotriticum was 2.79-, 1.38-, and 2.35-fold higher than that of bread wheat according to the 2,2-diphenyl-1picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and cupric ion reducing antioxidant capacity (CURPAC) methods, respectively. The free, bound, and total phenolic contents in xAgrotriticum were 1.34-, 1.59-, and 1.54-fold higher than those in bread wheat. The protein content (19.58 %) of xAgrotriticum was 1.48-fold higher than that of bread wheat. Essential amino acids constituted 28.65 % of the total amino acids in xAgrotriticum and 30.38 % in Fineway. Interestingly, methionine and tryptophan were present in xAgrotriticum although both were below the detection limits in wheat. However, compared with wheat, the arginine content of xAgrotriticum was 18-fold higher with glycine and tyrosine both 8-fold more abundant. xAgrotriticum has significantly richer iron, zinc, and copper contents; 1.31-, 1.74-, and 2.02-fold, respectively, than wheat. xAgrotriticum may offer potential for direct use as a foodstuff or raw material due to its nutritional elements, in addition to its potential as a genitor in hybridisation programs to improve the nutritional values of annual wheat and its prenniality which is considered one of the primary necessities for more sustainable agriculture.

Recent Advances in the Health Benefits of Phenolic Acids in Whole Grains and the Impact of Processing Techniques on Phenolic Acids: A Comprehensive Review

Phenolic acids, essential compounds in whole grains, are renowned for their health-enhancing antioxidant and anti-inflammatory properties. Variations in concentration, particularly of hydroxybenzoic and hydroxycinnamic acids, are observed among grain types. Their antiobesity and antidiabetes effects are linked to their modulation of key signaling pathways like AMPK and PI3K, crucial for metabolic regulation and the body's response to inflammation and oxidative stress. Processing methods significantly influence phenolic acid content and bioavailability in whole grains. Thermal techniques like boiling, baking, or roasting can degrade these compounds, with loss influenced by processing conditions. Nonthermal methods such as germination, fermentation, or their combination, can protect or enhance phenolic acid content under ideal conditions. Novel nonthermal approaches like ultrahigh pressure (UHP), irradiation, and pulsed electric fields (PEF) show promise in preserving these compounds. Further research is needed to fully comprehend the impact mechanisms of these innovative methods on the nutritional and sensory attributes of cereals.

The Effects of a Cultivar and Production System on the Qualitative and Quantitative Composition of Bioactive Compounds in Spring Wheat (Triticum sp.)

Spelt Triticum aestivum L. subsp. spelta (cv. Wirtas), einkorn Triticum monococcum L. (cv. Samopsza) and emmer Triticum dicoccum Schrank (Schuebl) (cv. Płaskurka biała and Płaskurka ciemna) spring wheat cultivars were analyzed and compared to common wheat Triticum aestivum L. subsp. aestivum (cv. Harenda, Kandela, Mandaryna, Serenada, Goplana, Kamelia, Nimfa, Rusałka, Struna, Zadra) cultivated in an organic production system. Moreover, the performance of four common wheat cultivars (cv. Harenda, Kandela, Mandaryna, Serenada) grown in organic, conventional and integrated production systems were compared. The UHPLC-DAD-MS and TLC-DPPH• analyses of specific substances (phenolic acids and alkylresorcinols) were evaluated to ascertain the potential of spring wheat cultivars for promoting human health and suitability for cultivation in an organic production system. The highest yield was observed for the T. aestivum L. subsp. aestivum (modern hull-less) cv. Nimfa (4.45 t/ha), which also demonstrated the lowest resistance to Fusarium spp. infection. Among the contemporary hull-less cultivars, cv. Mandaryna and cv. Harenda exhibited the highest resistance to this pathogen (2.4% and 3.7% of grains infected by Fusarium, respectively), while simultaneously displaying the highest organic phenolic acid content (900.92 and 984.55 µg/g of the grain) and the highest antioxidant potential. It is noteworthy that the cereal hulls of T. monococcum L. (old hulled) (cv. Samopsza) exhibited a markedly elevated content of phenolic acids (approximately 4000 µg/g of the grain). This may have contributed to the reduced incidence of Fusarium infection (9.3% of grains infected) observed in the grains of this cultivar. Furthermore, the hulls proved to be a rich source of phenolics with high antioxidant activity, which is beneficial for human and animal health.

Changes in physio-biochemical metabolism, phenolics and antioxidant capacity during germination of different wheat varieties

Changes in physio-biochemical metabolism, phenolics and antioxidant capacity during germination were studied in eight different wheat varieties. Results showed that germination enhanced sprout growth, and caused oxidative damage, but enhanced phenolics accumulation. Ferulic acid and p-coumaric acid were the main phenolic acids in wheat sprouts, and dihydroquercetin, quercetin and vitexin were the main flavonoids. The phenolic acid content of Jimai 44 was the highest on the 2th and 4th day of germination, and that of Bainong 307 was the highest on the 6th day. The flavonoid content of Hei jingang was the highest during whole germination. The enzymes activities of phenylalanine ammonia lyase (PAL), cinnamic acid 4-hydroxylase (C4H) and 4-coumarate coenzyme A ligase (4CL) were up-regulated. The activities of catalase, polyphenol oxidase and peroxidase were also activated. Antioxidant capacity of wheat sprouts was enhanced. The results provided new ideas for the production of naturally sourced phenolic rich foods.

Antitumor Effects of an Anthocyanin-Rich Grain Diet in a Mouse Model of Lewis Lung Carcinoma

Functional foods enriched with plant polyphenol anthocyanins attract particular attention due to their health-promoting properties, including antitumor activity. We evaluated the effects of a grain diet rich in anthocyanins in a mouse model of Lewis lung carcinoma. Mice of the C57BL/6 strain were fed with wheat of near-isogenic lines differing in the anthocyanin content for four months prior to tumor transplantation. Although a significant decrease in the size of the tumor and the number of metastases in the lungs was revealed in the groups with both types of grain diet, the highest percentage of animals without metastases and with attenuated cell proliferation in the primary tumor were observed in the mice with the anthocyanin-rich diet. Both grain diets reduced the body weight gain and spleen weight index. The antitumor effects of the grain diets were associated with the activation of different mechanisms: immune response of the allergic type with augmented interleukin(IL)-9 and eotaxin serum levels in mice fed with control grain vs. inhibition of the IL-6/LIF system accompanied by a decrease in the tumor-associated M2 macrophage marker arginase 1 gene mRNA levels and enhanced autophagy in the tumor evaluated by the mRNA levels of Beclin 1 gene. Thus, anthocyanin-rich wheat is suggested as a promising source of functional nutrition with confirmed in vivo antitumor activity.

Characterization of Polyphenol Composition and Starch and Protein Structure in Brown Rice Flour, Black Rice Flour and Their Mixtures

The study investigates the structural and chemical properties of brown rice flour (WRF), black rice flour (BRF) and their mixtures in ratios of 25%, 50% and 75% to provide reference information for the gluten-free bakery industry. BRF contains higher concentrations of proteins, lipids, total minerals, crude fiber, total polyphenols, proanthocyanidins and flavonoids than WRF. A higher amylose content in BRF than in WRF resulted in flour mixtures with slower starch digestion and a lower glycemic response depending on the BRF ratio added. Differences in the chemical composition of WRF and BRF led to improved composition of the flour mixtures depending on the BRF ratio. The presence of anthocyanidins and phenolic acids in higher concentrations in the BRF resulted in a red-blue color shift within the flour mixtures. The deconvoluted FTIR spectra showed a higher proportion of α-helixes in the amide I band of BRF proteins, indicating their tighter folding. An analysis of the FTIR spectra revealed a more compact starch structure in BRF than in WRF. By processing reflection spectra, nine optically active compound groups were distinguished in rice flour, the proportion in BRF being 83.02% higher than in WRF. Due to co-pigmentation, the bathochromic shift to higher wavelengths was expressed by the proanthocyanins and phenolic acids associated with the wavelengths 380 nm to 590 nm and at 695 nm. Anthocyanins, protein-tannin complexes, methylated anthocyanins and acylated anthocyanins, associated with wavelengths 619, 644 and 668 nm, exhibited a hypsochromic effect by shifting the wavelengths to lower values. This research represents a first step in the development of rice-based products with increased nutritional value and a lower glycemic index.

Whole Black Rice Flour Improves the Physicochemical, Glycemic, and Sensory Properties of Cracker Snacks

The present study describes the enhancement of the nutritional values of gluten-free rice crackers by adding whole black rice grain flour. The crackers were prepared by combining whole brown rice flour (WRF) and whole black rice flour (BRF) in ratios of 0% (WRC), 25% (25-BRC), 50% (50-BRC), 75% (75-BRC), and 100% (BRC). The resulting samples underwent in-vivo effects on postprandial blood glucose levels as well as physicochemical and sensory analysis. In comparison to WRC, the samples containing 100% added black rice flour presented higher nutritional qualities in terms of protein, by 16.61%, 8.64% for lipids, 5.61% for ash, 36.94% for crude fiber, 58.04% for total polyphenols, 95.49% for proanthocyanidins, and 88.07% for flavonoids. The addition of BRF had a suppressing effect on lightness (L*) and yellowness (b*), while redness (a*) increased. The results of the glycemic measurements confirmed that consumption of crackers made from brown or black whole-grain rice grain flour does not generate glycemic peaks above the limit of 30 mg/dL in baseline blood glucose levels. The results of developing rice crackers from black and brown flour blends showed promising physicochemical and nutritional properties and could provide a good alternative to wheat flour as a gluten-free product.

A New Functional Wheat Flour Flatbread (Bazlama) Enriched with High-β-Glucan Hull-Less Barley Flour

Although the Med-Diet is a healthy diet model, it is affected by current dietary habits. Therefore, new foods with improved nutritional value should be developed to respond to the needs of people following the Med-Diet. This study was focused on developing high-β-glucan flat bread (bazlama) with a relatively lower GI. A bread wheat (cv. Tosunbey) flour was enriched with the flour of a high-β-glucan-content hull-less barley (cv. Chifaa) flour (15, 30, 45 and 60%) to develop a functional bazlama. The nutritional and technological properties of bazlama samples enriched with barley flour were compared with the ones produced from bread wheat. All of the barley flour-enriched bazlama samples had higher yellowness values (b*) than the control (both crumb and crust), which is generally preferred by the consumers. Texture results indicated that bazlama samples became harder with the increase in barley flour supplementation level. The results showed that 3 g of β-glucan can be provided from the barley flour-enriched bazlama samples (at 45 and 60% levels), and this is the limit to carry health claims. The bazlama samples enriched with barley flour were richer in Mg, K, Mn, Fe, and Zn minerals than the control (100% Tosunbey flour). While the glycemic index (GI) of commercial bread wheat and Tosunbey bazlama samples were high (88.60% and 79.20%, respectively), GI values of the bazlama samples enriched with 60% (64.73) and 45% barley flour (68.65) were medium. The lower GI values of barley flour-enriched bazlama samples are probably due to the higher β-glucan contents of the bazlama samples. Additionally, as the barley flour supplementation level of the bazlama samples increased, the phenolics and antioxidant capacities of free and bound extracts increased compared to bread wheat bazlama. The results indicated that hull-less barley (cv. Chifaa) with high β-glucan content may be utilized at relatively higher levels (45 and 60%) to produce bazlama with improved nutritional properties.

Antioxidant Properties and Geroprotective Potential of Wheat Bran Extracts with Increased Content of Anthocyanins

In recent years, there has been a focus on breeding wheat with high anthocyanin levels in order to improve food quality and human health. The objective of this study was to examine the antioxidant and geroprotective properties of wheat bran extracts using both in vitro and in vivo research methods. Two wheat lines were used: one with uncolored pericarp (anthocyanin-free) and another with colored pericarp (anthocyanin-containing). These lines differed in a specific region of chromosome 2A containing the Pp3/TaMyc1 gene, which regulates anthocyanin production. High-performance liquid chromatography-mass spectrometry revealed the presence of cyanidin glucoside and cyanidin arabinoside in the anthocyanin-containing wheat bran extract (+AWBE), while no anthocyanins were found in the anthocyanin-free wheat bran extract (-AWBE). The +AWBE showed higher radical scavenging activity (DPPH and ABTS assays) and membrane protective activity (AAPH oxidative hemolysis model) compared to the -AWBE. Both extracts extended the lifespan of female Drosophila, indicating geroprotective properties. This study demonstrates that wheat bran extracts with high anthocyanin levels have antioxidant and geroprotective effects. However, other secondary metabolites in wheat bran can also contribute to its antioxidant and geroprotective potential.

Iono-metabolomic guided elucidation of arsenic induced physiological and metabolic dynamics in wheat genotypes

Despite the growing concerns about arsenic (As) toxicity, information on wheat adaptability in such an aggravating environment is limited. Thus, the present investigation based on an iono-metabolomic approach is aimed to decipher the response of wheat genotypes towards As toxicity. Wheat genotypes procured from natural conditions were characterized as high As-contaminated (Shri ram-303 and HD-2967) and low As-contaminated (Malviya-234 and DBW-17) based on ICP-MS As accumulation analysis. Reduced chlorophyll fluorescence attributes, grain yield and quality traits, and low grain nutrient status were accompanied by remarkable grain As accumulation in high As-contaminated genotypes, thus imposing a higher potential cancer risk and hazard quotient. Contrarily, in low As-contaminated genotypes, the richness of Zn, N, Fe, Mn, Na, K, Mg, and Ca could probably have supported less grain As accumulation, imparting better agronomic and grain quality traits. Additionally, from metabolomic analysis (LC-MS/MS and UHPLC), abundances of alanine, aspartate, glutamate, quercetin, isoliquiritigenin, trans-ferrulic, cinnamic, caffeic, and syringic bestow Malviya-234 as the best edible wheat genotype. Further, the multivariate statistical analysis (HCA, PCA, and PLS-DA) revealed certain other key metabolites (rutin, nobletin, myricetin, catechin, and naringenin) based genotypic discrimination that imparts strength to genotypes for better adaptation in harsh conditions. Out of the 5 metabolic pathways ascertained through topological analysis, the two main pathways vital for plant's metabolic adjustments in an As-induced environment were: 1. The alanine, aspartate and glutamate metabolism pathway, and 2. The flavonoid biosynthesis pathway. This is also evident from network analysis, which stipulates amino acid metabolism as a prominent As regulatory factor closely associated with flavonoids and phenolics. Therefore, the present findings are useful for wheat breeding programs to develop As adaptive genotypes that are beneficial for crop improvement and human health.

Quality, Nutritional Properties, and Glycemic Index of Colored Whole Wheat Breads

The main aim of this study was to investigate the quality and nutritional properties (dietary fiber, phenolic, antioxidant contents, and glycemic index) of breads made from whole wheat flours of colored wheats. White (cultivar Agronomicheskaya 5), red (Element 22), purple (EF 22 and Purple 8), and blue (Blue 10) colored wheats were used in the study. The whole wheat flours of Blue 10 and Purple 8 had higher farinograph stability, lower softening degree, and higher quality numbers indicating that they had better rheological properties. Bread produced from whole wheat flour of blue-colored grain had significantly higher loaf volume and better symmetry, crust color, crumb cell structure, and softness values among others (p < 0.05). The whole wheat bread produced using Element 22 had the highest crust and crumb L* color values, while Purple 8 and EF 22 had the lowest crust and crumb L* color values, suggesting that purple-colored grains have a tendency to make whole wheat bread with darker crust and crumb color. Bread produced from cultivar Blue 10 had the lowest firmness values while Element 22 had the highest firmness values. The highest total phenolic content and antioxidant capacity values were obtained from the whole wheat bread sample from purple-colored wheat (Purple 8). The whole wheat flour of Element 22 had the highest total dietary fiber content among all samples (p < 0.05). The differences between whole wheat bread samples in terms of total dietary fiber and glycemic index were not statistically significant. The results of the present study indicated that colored wheats can be used to produce whole wheat breads with higher nutritional properties and acceptable quality characteristics.

Phenolic Content and Antioxidant Capacity of Synthetic Hexaploid Wheats

In this study, 21 synthetic hexaploid wheat samples were analyzed and compared for phenolic content (the Folin-Ciocalteu method), phenolic compositions, and antioxidant activity (DPPH, ABTS, and CUPRAC). The aim of the study was to determine the phenolic content and antioxidant activity of synthetic wheat lines developed from Ae. Tauschii, which has a wide genetic diversity, to be used in breeding programs for developing new varieties with better nutritional properties. Bound, free, and total phenolic contents (TPCs) of wheat samples were determined as 145.38-258.55 mg GAE/100 g wheat, 188.19-369.38 mg GAE/100 g wheat, and 333.58-576.93 mg GAE/100 g wheat, respectively. Phenolic compositions were detected by the HPLC system. Gallic acid was found in the highest concentrations in free fractions, whereas gallic, p-coumaric acid, and chlorogenic acid were generally found in the highest concentrations in bound fractions of the synthetic hexaploid wheat samples. The antioxidant activities (AA%) of the wheat samples were evaluated by the DPPH assay. AA% in the free extracts of the synthetic red wheat samples ranged from 33.0% to 40.5%, and AA% values in the bound extracts of the synthetic hexaploid wheat samples varied between 34.4% and 50.6%. ABTS and CUPRAC analyses were also used to measure antioxidant activities. The ABTS values of the free and bound extracts and total ABTS values of the synthetic wheat samples ranged from 27.31 to 123.18, 61.65 to 263.23, and 93.94 to 308.07 mg TE/100 g, respectively. The corresponding CUPRAC values of the synthetic wheats were between 25.78-160.94, 75.35-308.13, and 107.51-364.79 mg TE/100 g. This study revealed that synthetic hexaploid wheat samples are valuable resources for breeding programs for developing new wheat varieties with higher concentrations and better compositions of health-beneficial phytochemicals. The samples w1 (Ukr.-Od. 1530.94/Ae. squarrosa (629)), w18 (Ukr.-Od. 1530.94/Ae. squarrosa (1027)), and w20 (Ukr.-Od. 1530.94/Ae. squarrosa (392)) can be used as a genetic resource in breeding programs to enhance the nutritional quality of wheat.

Purple Wheat: Food Development, Anthocyanin Stability, and Potential Health Benefits

Colored wheats such as black, blue, or purple wheat are receiving a great interest as healthy food ingredients due to their potential health-enhancing attributes. Purple wheat is an anthocyanin-pigmented grain that holds huge potential in food applications since wheat is the preferred source of energy and protein in human diet. Purple wheat is currently processed into a variety of foods with potent antioxidant properties, which have been demonstrated by in vitro studies. However, the health impacts of purple wheat foods in humans still require further investigations. Meanwhile, anthocyanins are vulnerable molecules that require special stabilization treatments during food preparation and processing. A number of stabilization methods such as co-pigmentation, self-association, encapsulation, metal binding, and adjusting processing conditions have been suggested as a means to diminish the loss of anthocyanins in processed foods and dietary supplements. The present review was intended to provide insights about purple wheat food product development and its roles in human health. In addition, methods for stabilizing anthocyanins during processing were briefly discussed.

Bioaccessibility and Antioxidant Activity of Polyphenols from Pigmented Barley and Wheat

Polyphenols in pigmented cereals are believed to enhance health outcomes through their antioxidant properties. This study aimed to characterise polyphenols from Hordeum vulgare (purple barley), Triticum turgidum (purple wheat) and Triticum aestivum (blue wheat) in order to evaluate their bioaccessibility and antioxidant activity. An ultra-high performance liquid chromatography mass spectrometry coupled with an online 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) system was used to identify the polyphenols and quantify their relative antioxidant levels. Simulated gastrointestinal digestion of the cereals allowed for the assessment of polyphenol bioaccessibility using benchtop assays. Between cereals, the bioaccessible phenolic content was similar following digestion, but the antioxidant activity was significantly different (purple barley > purple wheat > blue wheat; p < 0.01). Among the polyphenols identified, flavan-3-ols and anthocyanins were the least bioaccessible whereas flavones were the most bioaccessible after digestion. This study demonstrated that these pigmented cereal varieties are sources of bioaccessible polyphenols with antioxidant activity. These findings may aid in utilising these pigmented grains for the future design and development of novel functional food products with enhanced health properties.