Impact of milling on the nutrients and anti-nutrients in browntop millet (Urochloa ramosa) and its milled fractions: evaluation of their flour functionality.

BACKGROUND: Browntop millet has gained popularity in recent years owing to its nutritional superiority and health benefits. However, the usage of browntop millet flours as ingredients in composite flours and functional foods is constrained due to a lack of information regarding the grain composition and its flour functionality. Therefore, the distribution of nutrients, anti-nutrients in browntop millet milled fractions and their flour functionality was evaluated in comparison to whole grain flour. RESULTS: Bran fraction comprised the highest protein (13.7%) and fat contents (27%) among other fractions. Pearling of dehulled grains considerably reduced phytic acid, saponins and flatulence-causing oligosaccharides in pearled grain flours. Besides, this led to the enrichment of soluble fibre, minerals, phenolics and trypsin inhibitors in bran fraction. Milling also impacted flour functionality. Despite its lower water holding ability, dehulled grain flour exhibited significantly higher oil absorption capacity than whole grain flour due to the removal of fibre-rich hull fraction. Although emulsion (45.2%) and foaming capacities (12.5%) were superior in bran flour, foam stability was greater in pearled grain flours. CONCLUSION: These findings suggest the potential utilisation of browntop millet milled flours as ingredients in the development of distinct food formulations and as partial substitutes to wheat flour in confectionary and bakery products. © 2024 Society of Chemical Industry.

Implication of solvent polarities on browntop millet (Urochloa ramosa) phenolic antioxidants and their ability to protect oxidative DNA damage and inhibit α-amylase and α-glucosidase enzymes.

Phenolics of browntop millet extracted in solvents with varying polarities [water, methanol, acetone (80%), ethanol (70%)] were comparatively assessed for their phenolic profiles, antioxidant activities, DNA damage protection and enzyme inhibitory properties. Results indicated that acetone (80%) and ethanol (70%) were most effective in extracting millet phenolics than other solvents. Gallic, caffeic and ferulic acids were the major phenolic acids, myricetin and kaempferol were the most abundant flavonoids detected in all the extracts of browntop millet. Phenolics extracted in 80% acetone and 70% ethanol offered noticeable contributions toward several antioxidant mechanisms and prevented the oxidative DNA damage than water and methanol extracts. All the millet extracts exhibited potent inhibition towards α-glucosidase than α-amylase activities. These results suggest that the solvents and their polarities impacted the extraction and bioactivities of millet phenolics and provided useful information for the effective utilization of browntop millet as a functional food ingredient to manage hyperglycemia.

Impact of hydrothermal processing on squalene, α-tocopherol, and fatty acid content in Job's tears grain milled fractions: evaluation of their storage stability.

BACKGROUND: Job's tears possess an exceptionally high amount of fat and the unsaponifiable fraction is a potential source of bioactive compounds. The aim of this study was to determine the effect of hydrothermal processing on squalene, α-tocopherol, and fatty acids in the whole-grain, milled fractions, and their storage stability. RESULTS: The highest level of squalene content was found in the bran fractions of native and processed Job's tears (11.54-12.75 mg 100 g-1 ). A remarkably high amount of α-tocopherol was also found in the bran (59.75 ± 0.47 mg 100 g-1 ) and germ (67.05 ± 0.94 mg 100 g-1 ) of the processed grain fractions. The storage stability evaluation of these bioactive compounds in the polished grains revealed no significant difference between 0 and 15 days of storage under elevated temprature of 37 °C and 92% relative humidity (accelarated storage conidition) and retained the bioactive compounds longer in the processed grains. CONCLUSION: These results suggest that the processed Job's tears milled fractions with high bioactive compounds and improved shelf life can be used as food ingredients in product development. © 2020 Society of Chemical Industry.

Inhibition of protein glycoxidation and advanced glycation end-product formation by barnyard millet (Echinochloa frumentacea) phenolics.

Protein glycation plays a vital role in the progression of various diabetes complications. Therefore, inhibition of protein glycation could be a key strategy to prevent these diabetic abnormalities. Evaluation of phenolic compositions and their antiglycation activity revealed that p-coumaric and chlorogenic acids were major phenolic acids in barnyard millet. These phenolics exhibited multiple antioxidant activities in various mechanisms and protected the oxidative DNA damage and hydroxyl radical-induced protein fragmentation. Millet phenolics were very effective in scavenging >78% reactive carbonyl intermediates in the reaction and protected protein thiol group oxidation. Furthermore, 68.3% inhibition of protein glycation and reduced formation of protein aggregates were also observed with millet phenolics. Besides, fluorescence intensity measurements indicated a significant decrease in advance glycated end products and protection against glycoxidation-induced protein conformational changes at 100 µg/ml phenolics. These results suggest the potential utility of barnyard millet as an ingredient in functional foods for controlling protein glycation associated diabetic complications.

Phenolic antioxidants of foxtail and little millet cultivars and their inhibitory effects on α-amylase and α-glucosidase activities.

Evaluation of phenolic contents and their in vitro bioactivities of six diverse cultivars of foxtail and little millets revealed that their total phenolic content ranged from 19.42 to 24.12 µmol ferulic acid equivalents/g. The soluble fraction accounted for more than 80% of the total phenolic and flavonoid contents. Ferulic, caffeic and sinapic acids were the predominant phenolic acids, and luteolin and kaempferol were major flavonoids in the soluble fractions of millets. However, ferulic and p-coumaric acids were abundant in the bound fractions. Millet cultivars exhibited relevant changes in antioxidant activities in different mechanisms. Little millet cultivars showed superior inhibition of α-amylase and α-glucosidase than foxtail millet cultivars. The soluble and bound fractions of CO7 cultivar of foxtail millet (IC50, 22.37 and 57.26 µg/ml) and CO4 cultivar of little millet (IC50, 18.97 and 55.69 µg/ml) displayed strong inhibition towards α-glucosidase. These results suggest the potential application of underutilized millets as functional food ingredients for regulating postprandial hyperglycemia.

Lactucaxanthin - a potential anti-diabetic carotenoid from lettuce (Lactuca sativa) inhibits α-amylase and α-glucosidase activity in vitro and in diabetic rats.

Intestinal and pancreatic α-amylase and α-glucosidase inhibitors offer an approach to lower the levels of post-prandial hyperglycemia through the control of dietary starch breakdown in digestion. This study hypothesized that lactucaxanthin (Lxn) in lettuce (Lactuca sativa) inhibits the activity of α-amylase and α-glucosidase. In this study, the interaction of Lxn with α-amylase and α-glucosidase in silico and its inhibitory effect on these enzymes were studied using in vitro and STZ-induced diabetic rat models. Lxn was isolated from lettuce with 96% purity confirmed by HPLC and LCMS. The in silico analysis showed that Lxn has a lower binding energy (-6.05 and -6.34 kcal mol-1) with α-amylase and α-glucosidase compared to their synthetic inhibitors, acarbose (-0.21 kcal mol-1) and miglitol (-2.78 kcal mol-1), respectively. In vitro α-amylase and α-glucosidase inhibition assays revealed that Lxn had IC50 values of 435.5 µg mL-1 and 1.84 mg mL-1, but acarbose has values of 2.5 and 16.19 µg mL-1. The in vivo results showed an increased activity for α-amylase and α-glucosidase in the intestine (4.7 and 1.30 fold, p < 0.05) and pancreas (1.3 and 1.48 fold, p < 0.05) of STZ induced diabetic rats compared to normal rats. Whereas the activity decreased (p < 0.05) in the Lxn fed diabetic rats, except for the intestinal α-glucosidase activity (1.69 ± 0.12 PNP per min per mg protein). This was confirmed by the low blood glucose level (239.4 ± 18.2 mg dL-1) in diabetic rats fed Lxn compared to the diabetic group (572.2 ± 30.5 mg dL-1, p < 0.05). Lxn significantly inhibited (p < 0.05) the activity of α-amylase and α-glucosidase and could be of medical and nutritional relevance in the treatment of diabetes.

Processing effects on bioactive components and functional properties of moringa leaves: development of a snack and quality evaluation.

The effect of alkali pre-treatment on the nutritional, anti-nutritional and functional properties of moringa (Moringa oleifera) leaf flour (MLF), and sensory assessment of MLF-based snack product was investigated. The pre-treatment reduced the content of anti-nutrients, but improved the functional properties of MLF. The MLF-based ready-to-eat puffed snack exhibited high protein (21.6 g/100 g) and dietary fiber (14.8 g/100 g) contents while it contained a low fat content of 3.7 g/100 g. The HPLC analysis of phenolics revealed that chlorogenic and gallic acids were the predominant phenolic acids present in the raw leaf flour, whereas p-coumaric, caffeic and gallic acids were the major phenolic acids in the pre-treated leaf flour. Flavonoids such as catechin, kaempferol, rutin and luteolin were present in both MLFs and the prepared snack. Overall sensory quality indicated that the snacks had acceptable textural attributes and improved nutritional profile at the 20 % level of substitution. It is possible to develop a ready-to-eat convenience food product with good functional and nutritional properties using pre-treated moringa leaf.

Distribution of phenolic antioxidants in whole and milled fractions of quinoa and their inhibitory effects on α-amylase and α-glucosidase activities.

Whole grain quinoa and its milled fractions were evaluated for their phenolic composition in relation to their antioxidant properties and inhibitory effects on α-amylase and α-glucosidase activities. Compositional analysis by HPLC-DAD showed that the distribution of phenolic compounds in quinoa is not entirely localised in the outer layers of the kernel. Milling of whole grain quinoa resulted in about 30% loss of total phenolic content in milled grain. Ferulic and vanillic acids were the principal phenolic acids and rutin and quercetin were predominant flavonoids detected in whole grain and milled fractions. Quinoa milled fractions exhibited numerous antioxidant activities. Despite having relatively lower phenolic contents, dehulled and milled grain fractions showed significantly (p ⩽ 0.05) higher metal chelating activity than other fractions. Furthermore, extracts of bran and hull fractions displayed strong inhibition towards α-amylase [IC50, 108.68 µg/ml (bran) and 148.23 µg/ml (hulls)] and α-glucosidase [IC50, 62.1 µg/ml (bran) and 68.14 µg/ml (hulls)] activities. Thus, whole grain quinoa and its milled fractions may serve as functional food ingredients in gluten-free foods for promoting health.

Impact of processing on the phenolic profiles of small millets: evaluation of their antioxidant and enzyme inhibitory properties associated with hyperglycemia.

The effects of germination, steaming and microwave treatments of whole grain millets (barnyard, foxtail and proso) on their phenolic composition, antioxidant activities and inhibitory properties against α-amylase and α-glucosidase were investigated. Compositional analysis of phenolics by HPLC revealed that vanillic and ferulic acids were the principal phenolic acids and kaempferol was the predominant flavonoid found in raw millets. Different processing treatments brought about relevant changes in the composition and content of certain phenolic acids and flavonoids in processed millets. Phenolic extracts of raw and processed millets exhibited multiple antioxidant activities and are also potent inhibitors of α-amylase and α-glucosidase. In general, germinated millets showed highest phenolic content as well as superior antioxidant and enzyme inhibitory activities. These results suggest that germinated millet grains are potential source of phenolic antioxidants and also great sources of strong natural inhibitors for α-amylase and α-glucosidase.

Phenolic antioxidants in some Vigna species of legumes and their distinct inhibitory effects on α-glucosidase and pancreatic lipase activities.

Phenolic extracts of 4 Vigna species of legumes (mung bean, moth bean, and black and red varieties of adzuki beans) were evaluated for phenolic contents, antioxidant activities, and inhibitory properties against α-glucosidase and pancreatic lipase. Results showed that adzuki bean varieties contain higher phenolic indexes than mung bean and moth beans. Adzuki bean (black) variety was found to be the most active 2,2'-diphenyl-1-picrylhydrazyl and superoxide anion scavenger. However, the hydrogen peroxide scavenging and metal chelating abilities were significantly higher in adzuki bean (red) variety. Mung bean exhibited least antioxidant activities in all the methods tested. Phenolic extracts from these legumes also showed distinct variations in the inhibition of enzymes associated with hyperglycemia and hyperlipidemia. Inhibitory activities of all the extracts against lipase were found to be more potent than α-glucosidase. Although, α-glucosidase inhibitory activity was superior in the black variety of adzuki bean (IC(50,) 26.28 mg/mL), both adzuki bean varieties (black and red) along with moth bean showed strong inhibitory activities on lipase with no significant difference in their IC(50) values (7.32 to 9.85 mg/mL). These results suggest that Vigna species of legumes are potential source of antioxidant phenolics and also great sources of strong natural inhibitors for α-glucosidase and lipase activities. This information may help for effective utilization of these legumes as functional food ingredients for promoting health. Practical Application: Vigna species of legumes are good sources of phenolic antioxidants and strong natural inhibitors of enzymes associated with diabetes and obesity. Therefore, utilization of these legumes in the development of functional foods with increased therapeutic value would be a significant step toward health promotion and wellness.

Variability in the distribution of phenolic compounds in milled fractions of chickpea and horse gram: evaluation of their antioxidant properties.

Seed coat, cotyledon and embryonic axe fractions of chickpea (Cicer arietinum L.) and horse gram (Macrotyloma uniflorum L.) were evaluated for their phenolic composition in relation to antioxidant activities. Compositional analysis of phenolics by HPLC revealed a wide variation in the distribution of flavonols, isoflavones, phenolic acids and anthocyanins among these legume fractions. Although cotyledon fractions of both the legumes were rich in phenolic acids, the concentrations of flavonols such as quercetin, kaempferol, and myricetin were significantly (p < 0.05) lower than the embryonic axe and seed coat fractions. Ferulic, chlorogenic, caffeic, and vanillic acids were the principal phenolic acids found in cotyledons. The most striking difference was the predominance of isoflavones in embryonic axe fractions. Although the isoflavone genistein was detected in all three fractions of chickpea, it was present exclusively in the embryonic axe fraction of horse gram at levels greater than daidzein. Furthermore, cyanidin, petunidin, and delphinidin were detected in seed coat and embryonic axe fractions but not in cotyledons. In addition to these three anthocyanins, malvidin was found only in the horse gram seed coat fraction. Seed coat fractions having higher total phenolic indexes were found to be the most active 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavengers (IC(50) 13.1 to 18.6 microg/mL) followed by embryonic axe and cotyledon fractions (IC(50) 15.4 to 34.2 microg/mL). Hydrogen peroxide (H(2)O(2)) scavenging capacities of cotyledons, embryonic axe and seed coats were 12.3, 34.1 and 78.6% for chickpea and 15.1, 56.8 and 92.6% for horse gram, respectively. The multiple antioxidant activity of horse gram and chickpea fractions was evident, as they also possessed reducing power and ferrous ion-chelating potency. These results contributed to the understanding of the relationships between major phenolic compounds and antioxidant activities of legumes and provided useful information for effective utilization of legume-milled fractions as functional food ingredients for promoting health.

Distribution of nutrients and antinutrients in milled fractions of chickpea and horse gram: seed coat phenolics and their distinct modes of enzyme inhibition.

Milled fractions of chickpea ( Cicer arietinum L.) and horse gram ( Macrotyloma uniflorum L. Verdc.) were evaluated for their nutritional and antinutritional characteristics. Crude protein content of these fractions ranged from 22.6-23.8 g 100(-1) g in cotyledon to 7.3-9.1 g 100(-1) g in seed coat fractions. The fat content of chickpea fractions (1.6-7.8 g 100(-1) g) was higher than that of horse gram fractions (0.6-2.6 g 100(-1) g). Crude fiber content was higher in seed coat fractions of both legumes than embryonic axe and cotyledon fractions. Seed coat fractions had high dietary fiber content (28.2-36.4 g 100(-1) g), made up of mainly insoluble dietary fiber. Most of the phytic acid and oligosaccharides were located in the cotyledon fractions, whereas phenolic compounds in higher concentrations were found in seed coats. Significantly higher concentrations of proteinaceous and phenolic inhibitors of digestive enzymes were found in cotyledon and seed coat fractions, respectively. The kinetic studies, using Michaelis-Menten and Lineweaver-Burk derivations, revealed that seed coat phenolics inhibit alpha-amylase activity by mixed noncompetitive (chickpea) and noncompetitive (horse gram) inhibition mechanisms. In the case of trypsin, chickpea and horse gram seed coat phenolics showed noncompetitive and uncompetitive modes of inhibition, respectively. These results suggest the wide variability in the nutrient and antinutrient composition in different milled fractions of legumes and potential utility of these fractions as ingredients in functional food product development.

Nutritional implications and flour functionality of popped/expanded horse gram.

Utilization of horse gram and its flour in legume composite flours and products is limited due to the presence of antinutritional components, poor functional and expansion properties. Enzymatic treatment was used to improve the expansion and functional properties of horse gram to facilitate its use as an ingredient in food processing. Xylanase-mediated depolymerization of cell wall polysaccharides of horse gram lead to the development of a new expanded/popped horse gram. Expansion process of enzyme treated horse gram resulted in increased length (5.3-6.8mm) and higher yield of expanded grains (63-98%). The expanded horse gram had lower bulk density, higher protein digestibility and more resistant starch compared to the control raw grains. Dietary fibre content of raw and processed horse gram was in the range of 14.57-16.14%. High temperature short time (HTST) conditions used during expansion process lowered the levels of phytic acid, tannins and protease inhibitors by 46%, 61% and 92%, respectively. The flour obtained from xylanase treated and expanded horse gram had higher water (204.3g/100g) and oil absorption capacities (98.4g/100g) than unprocessed flour, which had 135.8g/100g and 74.6g/100g, respectively at ambient conditions. There was a decrease in foaming capacity and foam stability in expanded gram flour. However, emulsion stability increased significantly in the processed samples. Thus, the study indicated that nutritional value and flour functionality of horse gram could be improved by processing it into a new expanded product that can be used as an ingredient in food processing.