Catechin Equivalents Research Articles

Comparison of the Phenolic Profiles of Juice and Cider Derived from Machine- and Hand-harvested ‘Brown Snout’ Specialty Cider Apples in Northwest Washington

‘Brown Snout’ cider apple (Malus ×domestica) is desired by cider makers for its relatively high levels of phenolics, and over-the-row machine harvesting of ‘Brown Snout’ has been demonstrated to provide similar yield to hand harvest at a significantly lower cost. The purpose of this study was to determine if there is a measurable impact of harvest method on the phenolic profile of ‘Brown Snout’ juice and cider to better inform equipment adoption recommendations. Using a redox titration assay, the titratable tannin content (± SE) of juice (0.19% ± 0.01%) and cider (0.19% ± 0.01%) were found not to differ due to harvest method. Using a protein precipitation assay, juice from machine-harvested fruit was found to have lower levels of total tannins [231 ± 36 mg·L−1 catechin equivalents (CE)] than juice from hand-harvested fruit (420 ± 14 mg·L−1 CE). However, the total tannins of cider did not differ due to harvest method, the overall average for machine and hand harvest was 203 ± 22 mg·L−1 CE. The total phenolics of juice and cider did not differ due to harvest method (1415 ± 98 mg·L−1 CE and 1431 ± 73 mg·L−1 CE, respectively). Discriminant analysis based on an average of 33 tentatively identified phenolic compounds, as measured by ultra-high performance liquid chromatography coupled with quadrupole time of flight mass spectrometry, showed no separation due to harvest method in juice or cider. In conclusion, over-the-row machine harvesting of ‘Brown Snout’ resulted in a final product of similar quality at reduced labor costs, and thus shows potential for increasing the commercial sustainability of cider apple operations.

Exploration of Antidiabetic Activity of Stephania japonica Leaf Extract in Alloxan-Induced Swiss Albino Diabetic Mice

Aims: Presently the medicinal world is rapidly turning more on the therapeutic health benefits of natural product and medicinal plants in the management of major crucial disease and their complications. Medicinal plant, Stephania japonica has been studied for exploring antidiabetic potentiality as an alternative source of medicine against the global threat of Diabetes mellitus (DM).
 Methods: The extraction of S. japonica leaf was carried out by acetone and ethanol. Phytochemical screening and quantitative analysis of S. japonica leaf extracts were evaluated through chemically forming characterized color formation and calibration method respectively, by using standard reference substances (ascorbic acid, gallic acid, and quercetin) to assess the probable compounds present in the extract. Anti-diabetic potentiality of highest phytochemicals containing two extracts were investigated in in vitro as a ⍺-amylase inhibitors and in vivo through alloxan-induced Swiss albino diabetes mice model.
 Results: Alkaloids, carbohydrates, steroids, flavonoids, resins, saponins, tannins and coumarins were present in the leaf extracts. The estimated amount of total phenolics, flavonoids, flavonols and proanthrocyanidins contents of acetone and ethanol extract were 92.12±0.64 and 56.54±1.05 mg of gallic acid equivalent (GAE)/gm of dry extract, 66.02±1.42 and 46.17±0.54 mg of catechin equivalent (CAE)/gm of dry extract, 7.05±0.108 and 5.26±0.083 mg of quercetin equivalent (QUE)/gm of dry extract, 35.19±0.67 and 9.55±1.11 mg CAE/gm of dry extract, respectively. In 3, 5-dinitrosalicylic acid method, acetone and ethanol extract showed α-amylase inhibition of 51.02% and 46.62%, respectively at the concentration of 1000 µg/mL whereas in starch iodine color assay, acetone and ethanol extract showed inhibition of 57.32% and 52.12%, respectively at the concentration of 800 µg/mL. In contrast, both of the leaf extracts significantly (p<0.05 to p<0.001) improved the lipid profile parameters, blood glucose level and serum hepatic marker proteins in alloxan-induced diabetic mice.
 Conclusion: The present study strongly concluded that S. japonica leaf extracts process potent antidiabetic potentiality that might be significance for the management of diabetes and its complications.

Polyphenolic Composition of Rosa canina, Rosa sempervivens and Pyrocantha coccinea Extracts and Assessment of Their Antioxidant Activity in Human Endothelial Cells.

The aim of the present study was the investigation of the antioxidant activity of plant extracts from Rosa canina, Rosa sempervivens and Pyrocantha coccinea. The results showed that the bioactive compounds found at higher concentrations were in the R. canina extract: hyperoside, astragalin, rutin, (+)-catechin and (-)-epicatechin; in the R. sempervirens extract: quinic acid, (+)-catechin, (−)-epicatechin, astragalin and hyperoside; and in the P. coccinea extract: hyperoside, rutin, (−)-epicatechin, (+)-catechin, astragalin, vanillin, syringic acid and chlorogenic acid. The total polyphenolic content was 290.00, 267.67 and 226.93 mg Gallic Acid Equivalent (GAE)/g dw, and the total flavonoid content 118.56, 65.78 and 99.16 mg Catechin Equivalent (CE)/g dw for R. caninna, R. sempervirens and P. coccinea extracts, respectively. The extracts exhibited radical scavenging activity in DPPH and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS)•+ assays and protection from ROO•-induced DNA damage in the following potency order: R. canina > R. sempervirens > P. coccinea. Finally, treatment with R. canina and P. coccinea extract significantly increased the levels of the antioxidant molecule glutathione, while R. canina extract significantly decreased Reactive Oxygen Species (ROS) in endothelial cells. The results herein indicated that the R. canina extract in particular may be used for developing food supplements or biofunctional foods for the prevention of oxidative stress-induced pathological conditions of endothelium.

Cressa cretica L. growing in Egypt: Phytochemical study and potential antioxidant and hepato-protective activities

The present research was conducted to study the phytochemical constituents of the successive extracts of aerial parts of Cressa cretica L. and their antioxidant and hepatoprotective activities. Phenolic and flavonoid contents and their respective compounds were determined in ethyl acetate and 70% ethanol extract using chromatographic and spectral analyses. Unsaponifiable matter (USM) and fatty acids were investigated in lipoidal matter by GC/MS analysis. In-vitro DPPH radical scavenging activity and safety of successive extracts were assessed. The hepatoprotective effect of the safest extracts was evaluated in CCl4 intoxicated rats. Results showed that total phenolic contents were 21.07 and 22.95 mg gallic aid equivalent/g in ethyl acetate and 70% ethanol extract, respectively while total flavonoid contents were 6.25 and 10.18 mg catechin equivalent /g, respectively. Catechin and chlorogenic acid were the major phenolic compounds in ethyl acetate and ethanol extract, while rutin and apigenin-7-glucoside were the predominant flavonoids, respectively. Phytol was the major compound in USM while 14-methyl-pentadecanoic acid was the predominant fatty acid. The most promising antioxidant was 70% ethanol extract. Ethyl acetate, 70% ethanol and petroleum ether extracts showed complete safety and produced hepatoprotective effect; ethyl acetate and 70% ethanol extracts were superior and comparable to silymarin and even more potent concerning specific biomarkers and histopathology.

Antioxidant Activity, Total Phenols, Flavonoids and LCMS Profile of Chamaecrista hildebrandtii (Vatke) Lock and Clerodendrum rotundifolium (Oliv.)

Aims: The purpose of the study was to determine the antioxidant activity, quantify total phenols and total flavonoids and characterize the secondary metabolites present in methanolic extracts of Chamaecrista hildebrandtii and Clerodendrum rotundifolium using liquid chromatography coupled to mass spectrometry (LC-MS).
 Methodology: The total phenol and flavonoid contents were determined spectrophotometrically while the antioxidant activity was evaluated using the 2, 2-Diphenyl-1-Picrylhydrazyl (DPPH) free radical scavenging method. The secondary metabolites present in the methanolic leaves extracts were evaluated using LC-MS.
 Results: The extracts of C. hildebrandtii showed a significantly higher antioxidant activity (IC50 = 8.7 mg/mL) compared to C. rotundifolium (IC50= 28.5 mg/mL). Both methanolic extracts of C. hildebrandtii and C. rotundifolium had common and different types of flavonoids such as quercetin, rutin, (+)-catechin 3-O-gallate and luteolin 6-C-glucoside among others that could be responsible for the observed antioxidant activity. The total phenolic content of C. hildebrandtii (1.33±0.07 mg/g tannic acid equivalents) was significantly higher than that of C. rotundifolium (0.25±0.00 mg/g tannic acid equivalents). However, there was no statistically significant difference (p>0.05) in total flavonoid content of C. hildebrandtii (2.69±0.33 mg/g catechin equivalents) and C. rotundifolium (2.36±0.16 mg/g catechin equivalents).
 Conclusion: The results of the present study suggested that the good antioxidant activity exhibited by C. hildebrandtii may probably have been brought about by various secondary metabolites functioning in synergy.

Nutritional and phytochemical content of Swiss chard from Montenegro, under different fertilization and irrigation treatments

PurposeThe purpose of this paper is to evaluate both nutrient and phytochemical content of Swiss chard grown under different fertilization and irrigation treatments and the effect of these treatments on the tested parameters.Design/methodology/approachSamples of fresh Swiss chard were collected from the experimental field of Ljeskopolje, Montenegro, where chard was grown under different fertilization and irrigation treatments. Swiss chard samples were analyzed for nutritional and antioxidant parameters.FindingsIn this study, the authors found that 100 g of Swiss chard is a good source of total chlorophyll (47.13 mg), carotenoids (9.85 mg), minerals as well as vitamin C (26.88 mg) expressed as mean values. Total phenol and flavonoid compounds content were (138.59 µg gallic acid equivalent (GAE) and 11.91 µg catechin equivalent (CAE) per mg of water extract, respectively), also expressed as mean values. The total antioxidant capacity (IC50 values) determined by 1,1-diphenyl-2-picrylhydrazyl assay ranged from 2.93 to 4.44 mg/mL of aquatic water extract. Different fertilization regimes affected the following parameters: phosphorous, protein content, chlorophyll a, chlorophyll b and vitamin C (p<0.05), while different irrigation regimes did not have any effect on the tested parameters (p>0.05), while interaction effect between fertilization and irrigation was found only for sodium and copper (p<0.05).Originality/valueSwiss chard produced in Montenegro on a sandy clay loam soil with acid reaction contains appreciable amount of minerals, crude fibers, vitamin C, chlorophylls, carotenoids and polyphenols. The nutrient and phytochemical content of chard is equal or superior to other green leafy vegetables which are considered as functional food. It was identified as a potentially rich source of essential nutrients and phytochemical compounds. The promotion of higher consumption and production of Swiss chard may represent a natural and sustainable alternative for improving human health.

Effect of Ultrasound-Assisted Extraction of Moringa stenopetala Leaves on Bioactive Compounds and Their Antioxidant Activity.

SUMMARYMoringa stenopetala is a multipurpose plant having high nutritional and medicinal values. The aim of this study is to evaluate the effect of time and temperature of ultrasound-assisted extraction on bioactive compounds and antioxidant activities of M. stenopetala leaf extract. The ultrasound-assisted extraction took place at each of 30, 40 and 50 °C for 10, 20 and 30 min. The study also included the analysis of the interaction effects of time and temperature on the total phenolic content, total flavonoid content, antioxidant activity (ABTS and DPPH assay), FRAP and chelating activity. The highest total phenolic content, expressed in mg gallic acid equivalents per g dry mass, was 46.6 and total flavonoid content, expressed in mg catechin equivalents per g dry mass, was 20.4 at 40 °C for 20 min. Under the same conditions, the highest antioxidant activities evaluated by DPPH, ABTS and FRAP, expressed in mg Trolox equivalents per g dry mass, were 336.5, 581.8 and 133.3 respectively, and chelating activity, expressed in mg EDTA equivalents per g dry mass, was 28.4. The lowest amounts of bioactive compounds and antioxidant activities were observable when the extraction occurred at 50 °C for 30 min, followed by the extraction at lower temperature (30 °C) for shorter time (10 min). The morphological analysis of the residues obtained after extraction using scanning electron microscope indicated that there was a higher ultrasonic destruction of the structural components of the sample at longer extraction time. Therefore, ultrasound-assisted extraction at a temperature of 40 °C for 20 min is the best time-temperature combination to extract bioactive compounds from M. stenopetala leaves.

Domestic processing and storage on the physical-chemical characteristics of acerola juice (Malpighia glabra L.).

ABSTRACT Acerola is a tropical fruit that stands out for its high content of ascorbic acid and phenolic compounds. However, there is currently a lack of information on the effects of the preparation and domestic storage of fruit juices, especially that of acerola. The objective of this work was to evaluate the effect of different liquefying times (10, 30 and 50 s) and cold storage at 4 °C for 0, 24, 48 and 72 h in domestic acerola juice. In relation to such, physicochemical determinations were performed, including pH, total titratable acidity, antioxidant potential, contents of phenolic compounds and total flavonoids in juices produced from the whole fruit, the pulp and acerola seed extracts. Whole fruit juice, liquefied for 10 s, had the highest pH and lowest acidity averages (P≤0.05). The contents of phenolic and flavonoid compounds ranged from 26.06±1.18 to 168.34±24.63 mg of gallic acid equivalents (GAE)/100 mL and 11.17±0.96 to 49.45±1.43 mg of catechin equivalents (CE)/100 mL, respectively. Total phenolics were higher in whole acerola juices and total flavonoids in seed extracts, both when liquefied for 50 s. The antioxidant potential ranged from 0.12±0.01 to 4.26±0.78 mmol of Trolox equivalents (TE)/100 mL, and was also higher in whole acerola juice, liquefied for 50 s (P≤0.05). The results showed that acerola pulp has higher phenolic content and antioxidant potential, while seeds have more flavonoids. The liquefying time of the whole fruit for 50 s and consumption during the first 24 h, were the best conditions tested in this study, for obtaining a juice with a high content of phenolic and antioxidant activity.

Phytochemical screening and antimicrobial activity testing of crude hydroalcoholic extract from leaves of Sphagneticola trilobata (Asteraceae)

ABSTRACT: This study aimed to perform phytochemical analysis and to test the antimicrobial activity of the crude hydroalcoholic extract obtained from the leaves of Sphagneticola trilobata. Classes of secondary metabolites present in the extract were identified through phytochemical screening using analytical thin-layer chromatography. Antimicrobial activity was evaluated by testing cultures of Staphylococcus aureus, S. epidermidis, Staphylococcus spp., Escherichia coli, Serratia marcescens, Enterococcus faecalis, Pseudomonas aeruginosa, Salmonella Typhimurium, and Klebsiella pneumoniae isolated from human skin and those of Staphylococcus spp. isolated from dog skin using the broth microdilution method. In the phytochemical screening, classes of anthracenic derivatives and mono-, sesqui-, and diterpenes were identified. Colorimetric analysis showed total phenol and total flavonoid contents of 21.7 ± 0.009 mg of gallic acid equivalents per gram of sample and 0.23 ± 0.005 mg of catechin equivalents per gram of sample, respectively. Microbiological analysis revealed that the hydroalcoholic extract of S. trilobata exhibited antimicrobial activity against cultures of Staphylococcus spp., E. coli, S. marcescens, and E. faecalis isolated from human skin and those of Staphylococcus spp. isolated from dog skin. Thus, crude hydroalcoholic extract of leaves of S. trilobata contained flavonoids and terpenoids as secondary metabolites, which contributed to its antimicrobial activity against skin bacteria isolated from different sources.

Bioactive compounds and antioxidant activity of seventeen Moroccan date varieties and clones (Phoenix dactylifera L.)

Dates are known to have a wide range of biological properties due to their bioactive compounds and antioxidant activities. The majority of Moroccan varieties and clones are not characterised for their bioactive compounds and their contribution to the total antioxidant activity.The aim of this research was to investigate the biochemical properties and antioxidant activities of 17 dates varieties and clones from Drâa oasis (southern Morocco) which have not been characterised yet. The results indicated that the total phenolic content was found between 101.06 and 478.37 mg of gallic acid equivalent (GAE)/100 g of dry matter (DM), the total flavonoids levels are between 1.79 and 216.12 mg of quercetin equivalent (QE)/100 g of dry matter (DM), and condensed tannins values range is between 5.29 and 152.15 mg of catechin equivalent (CE)/100 g dry matter (DM), and the antioxidant activity ranged between 0.219 and 2.028 mg/ml for FRAP IC50, 2.411 and 9.738 mg/ml for DPPH IC50. This study showed that date fruit is a veritable source of functional nutrients and natural antioxidants. Therefore, Moroccan dates can be used as a food or functional ingredient in food products.

Differences in antioxidant activity, total phenolic and flavonoid contents of commercial and homemade tomato pastes

Abstract Tomato paste is an important industrial product of food industry, which has been also produced in the homes of tomato producing countries. Although literature on the physical and chemical composition of commercial and homemade types of tomato pastes is available, studies on their antioxidant activity (ABTS), total phenolic content (TPC) and total flavonoid content (TFC) are inexistent. The aim of this study is to compare the TPC, TFC and ABTS values of homemade and commercial types of tomato pastes, as well as their pH, brix and color values. Commercial (n = 9) and homemade (n = 6) tomato pastes were obtained from either national markets or homes that produce tomato pastes in various cities of Turkey. The TPC and TFC values of commercial tomato pastes were 209.62 ± 17.02 mg gallic acid equivalent (GAE) and 42.52 ± 4.85 mg catechin equivalent (CE), respectively, and they were significantly higher (p

Effects of Maturity at Harvest and Fermentation Conditions on Bioactive Compounds of Cocoa Beans.

Cocoa beans and cocoa products contain considerable amounts of bioactive compounds. Harvesting cocoa fruit too early or too late may have effects on the phenolic and alkaloid concentrations of the cocoa powder. Fermentation, a primary processing used to transform cocoa beans to cocoa powder, may also influence the contents of bioactive compounds. In this study, proanthocyanidins, the major compounds in cocoa polyphenols, caffeine and theobromine of cocoa beans, were evaluated at different maturities at harvest, and with different fermentation durations, with and without the addition of a commercial enzyme, Pectinex® Ultra SP-L. The amounts of proanthocyanidins, caffeine and theobromine, and the antioxidant capacities of the unfermented cocoa beans increased as the fruits matured. The values ranged from 16.12-27.28g catechin equivalents (CE)/100g dry weight (DW); 99.66-173.61mg/100g DW; 556.39-948.84mg/100g DW; 23.23-26.32mol Trolox equivalents (TE)/100g DW, respectively. Prolonged fermentation with or without the addition of pectinase, from three to seven days, significantly reduced the amounts of these compounds present. Fermentation using the enzyme significantly reduced the proanthocyanidin content and antioxidant capacity of the cocoa powder, with the overall means decreasing from 8.93-4.93gCE/100g DW and from 15.81-12.95gmol TE/100g DW, respectively. Two-way ANOVA analyses showed that the proanthocyanidins, caffeine, theobromine contents and the antioxidant capacity of cocoa beans were strongly dependet to their stages of maturity, fermentation methods and fermentation duration.

Different drying temperatures modulate chemical and antioxidant properties of mandai cempedak (Artocarpus integer)

Background: Mandai, the fermented inner skin of cempedak (Artocarpus integer), may have further use as industrial ingredient while maintaining its antioxidative capacity. To promote fermentation, Lactobacillus casei was induced as the starter culture. This research was carried out (i) to investigate the effect of temperature on yield, chemical properties, and antioxidant activity of starter induced fermented mandai powder, (ii) to find the best drying temperature for the powder, and (iii) to find correlations between phenolic contents and antioxidant activity of the powder. Methods: The drying temperature was used as the variable, and was set at 45, 50, and 55°C at a fixed duration of 18 hours. The control was spontaneously fermented mandai dried at 50°C for 18 hours. Total phenolic content (TPC), hydrolyzed tannic content (HTC), and total flavonoid content (TFC) were spectrophotometrically measured, expressed gallic acid (GAE), tannic acid (TAE), and catechin (CAE) equivalents. Antioxidant capacity was measured by DPPH assay. Results: The best mandai powder had total phenolic content of 348.8±55.6 mg GAE kg-1, HTC of 143.8±9.3 mg TAE kg-1, TFC of 17.5±1.3 mg CAE kg-1, antioxidant activity (IC50) of 56.96 ppm, ash content of 4.0±0.7%, pH value of 5.0±0.8, and yield of 9.3±0.8%. There was a strong correlation between TPC, HTC, TFC, and the antioxidant activity. Conclusions: Drying temperature affected all observed parameters but not ash and pH. Temperature of 45°C emerged as the best treatment to produce mandai powder from L. casei-inoculated mandai cempedak fermentation. The antioxidant activity of mandai cempedak was contributed by the phenolic components.

Microencapsulation of grape skin phenolics for pH controlled release of antiglycation agents

Grape skin (GS) phenolics can prevent structural damage of proteins due to reducing sugars or dicarbonyl compounds, which is the leading cause of hyperglycaemia damage and is involved in inflammatory diseases. In this study, alginate hydrogel was used to encapsulate GS phenolics as a pH dependent releasing system. Microbeads were obtained by a vibrating nozzle method using calcium chloride as hardening agent. Encapsulation efficiency for total phenolics was 68%. At pH 1.4, the alginate microbeads remained intact and only 13% of total phenolic compounds of the microbeads was released. The percent release depended on the compound: procyanidin B1 release was 74%, catechin and epicatechin release was ~ 50%, while anthocyanin and flavonol release was less than 11%. At pH 7.4, the microbeads were dissolved and formed a viscous solution that showed ability to protect bovine serum albumin from glycation induced by both fructose and methylglyoxal. The antiglycation activity was 246 mmol catechin equivalents (CE)/kg of dry microbeads in the fructose model system and 78 mmol CE/kg of dry microbeads in the methylglyoxal model system. These values corresponded to 68% and 62% of the expected activity, probably due to interaction between phenolics and the alginate carrier. Despite the recovery of antiglycation activity was incomplete, results of this study confirmed the efficiency of alginate to act as a pH controlled released system for GS phenolics. This functionalized polymer could be applied in the prevention of advanced-glycation-endproducts related diseases.

A comparative study of phytochemicals, antioxidant potential and in-vitro DNA damage protection activity of different oat (Avena sativa) cultivars from India

Eight Indian oat cultivars collected from different areas were investigated for the presence of bioactive compounds, their antioxidant capacities and in-vitro DNA damage protection activity. Different assays were used for quantification of antioxidant activities in oat cultivars. Preliminary analysis revealed that all oat cultivars (cv.) were rich in specific phytochemicals as their extracts showed the presence of coumarins, saponins, flavonoids, flavones, proteins, tocols, β-glucan and carbohydrates. The total phenolic and condensed tannin contents of oat cultivars ranged between 7.6 and 16.8 mg gallic acid equivalent (GAE) g−1 and 27.3–107.3 mg catechin equivalent (CE) 100 g−1, respectively. Comparisons of antioxidant activity of all oat cultivars showed that OS-6 cv. possessed the highest inhibition towards 2, 2-diphenyl-1′ picrylhydrazyl (DPPH) and 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+) radicals and also higher reducing power (8.4 mg quercetin equivalent g−1). All the extracts protected DNA from damaging effect produced during Fenton’s reaction as confirmed by the presence of DNA bands. The results indicated that phenolic compounds are potent radical scavengers as phenolic content was positively correlated to various antioxidant assays studied. The information provided in the present study will help plant breeders to select specific cv. which is rich in phenolics and other important bioactive compounds.

PHENOLIC COMPOUNDS CONTENT, ANTIOXIDANT AND ANTIDIABETIC POTENTIALS OF SEVEN EDIBLE LEAVES

The objectives of this study were to investigate antioxidant and enzyme inhibitory activity of ethanolic and aqueous extracts of seven leaves. The antioxidant activity of the leaves was determined by two different methods: DPPH and β-carotene- bleaching test (βC). The enzyme inhibitory activity was evaluated against α-glucosidase. Antioxidant (EC50) and α-glucosidase (IC50) activity were determined as 8.29-238.8 g of leaf/g of DPPH and 35.59-620.29 μg/mL respectively. Among seven leaves studied, leaf of grape (Vitis vinifera), quince (Cydonia oblonga) and nettle (Urtica dioica) exhibited higher antioxidant and α-glucosidase inhibition activity than the rest of the leaves. Total phenolic content (TPC), total flavonoid content (TFC) and total hydrolyzable tannin content (TTC) of the leaves were between 0.22-16.37 mg gallic acid equivalents (GAE), 0.07-9.32 mg catechin equivalents (CE) and 0.49-16.38 tannic acid equivalent (TAE) per g of leaf, respectively.

Measurement of catechin-7-O -glucoside from barley to malt

The content of catechin-7-O-glucoside throughout the malting process was evaluated by high-performance liquid chromatography with diode-array detection coupled to electrospray ionisation tandem mass spectrometry (HPLC-DAD-ESI/MS) in 10 Czech varieties of barley and corresponding malts. Glycosylation confers catechin better water solubility and resistance to oxidative and alkaline degradation, with a significant impact on beer quality. However, the sugar moiety also affects catechin bioavailability and may hinder its health effects. The results show that the total catechin-7-O-glucoside content is higher in malt [ranging from 22.3 ± 0.7 to 84 ± 6 mg catechin equivalents (CE)/kg] compared with barley (from 6.3 ± 0.4 to 36 ± 1 mg CE/kg). The catechin-7-O-glucoside content ratio between malt and barley varied from ~1.5- to 7-fold for varieties Pioner and Sunshine, respectively. The study of the glycosylation rate during individual stages of the malting process using a barley variety Tipple revealed that the content of catechin-7-O-glucoside gradually increases (0.26 mg CE/kg/h) during the germination stage (~3-fold higher after 120 h of germination). In addition, the glycosylation rate is 5 times faster during kilning steps (1.36 mg CE/kg/h) and its content almost doubles after kilning. The first steps of the kilning stage encompass optimal moisture and temperature for enzyme activity (~45% moisture and 55°C) which may explain the higher catechin-7-O-glucoside formation rate. © 2018 The Institute of Brewing & Distilling

Profile of phenolic compounds and antioxidant activity of finger millet varieties

The profiles of phenolic compounds and antioxidant capacities of four finger millet varieties harvested in northern Malawi were investigated. The total phenolics, flavonoids and condensed tannins in the free fractions ranged from 114.43 to 179.19 mg ferulic acid equivalent (FAE)/100 g, 90.24 to 202.94 mg catechin equivalent (CE)/100 g and 31.76 to 83.59 mg CE/100 g, respectively. Total phenolic contents of the bound fractions ranged from 58.27 to 123.23 mg FAE/100 g. Twenty phenolic compounds were identified in the free fractions including eighteen flavonoids, with catechin and epicatechin being the predominant flavonoids. Seventeen phenolic compounds were identified in the bound fractions, with ferulic acid being the predominant one. Ten of the identified polyphenols were firstly reported in finger millet. Darker colored finger millet varieties had higher phenolic contents and antioxidant properties than the lighter colored ones. Finger millet can be used as healthy food material and natural antioxidant resource.

Encapsulation of stevia rebaudiana Bertoni aqueous crude extracts by ionic gelation – Effects of alginate blends and gelling solutions on the polyphenolic profile

We formulated and characterised two alginate blends for the encapsulation of stevia extract (SE) via ionic gelation through an extrusion technique. Calcium chloride in SE and calcium chloride solutions were assessed as crosslinkers to overcome phenolic losses by diffusion and increase encapsulation efficiency (EE). Regardless of the blend, all stevia-loaded beads exhibited high EE (62.7–101.0%). The size of the beads decreased as EE increased. Fourier transform infrared analysis showed increased hydrogen bonding between SE and alginates, confirming the successful incorporation of SE within the matrix. Untargeted metabolomics profiling identified 479 free and encapsulated polyphenolic compounds. Flavonoids (catechin and luteolin equivalents) were predominant in SE whereas tyrosols and 5-pentadecylresorcinol equivalents were predominant in all bead formulations. Three-common discriminant compounds were exclusive to each blend and were inversely affected by the crosslinking conditions. Both alginate blends have been shown to be feasible as carrier systems of stevia extracts independent of crosslinking conditions.

Antioxidant and antifungal activity of carnauba wax powder extracts

Carnauba wax is a commercially valuable product derived from epicuticular wax powder (CWP) from the leaves of Copernicia prunifera (Arecaceae), a palm tree native to northeastern Brazil. CWP exists as a fine powder on both young, upright, closed leaves (type A wax), and mature, pendant, open leaves (type B wax). The aim of this study was to evaluate the effect of extraction time on aqueous and ethanolic extracts of carnauba wax powder and quantify their antioxidant potential. Furthermore, we determined the total phenols, flavonoids, and flavonols in the extracts, and tested the effects of the extracts on the dermatophyte fungi Trichophyton rubrum and Microsporum canis. Antioxidant capacity was evaluated by measuring the scavenging effect of the extracts on 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radicals. Overall, higher extract yields were obtained using ethanol as a solvent, rather than water. All extracts showed antioxidant activity and the extraction time did not influence the antioxidant activity of the extracts; the strongest activity was observed for the ethanolic extract of type B wax powder (EtB) with an EC50 values of 365 ± 7 μg/mL (by DPPH assay) and 317 ± 6 μg/mL (by ABTS). Total phenolic, flavonoid, and flavanol contents varied from 280.73 ± 4.85 to 114.06 ± 4.45 gallic acid equivalents (GAE), 24.59 ± 0.45 to 5.34 ± 0.12 quercetin equivalents (QE), and 32.36 ± 0.93 to 9.41 ± 0.37 catechin equivalents (CTE), respectively. Qualitative high-performance liquid chromatography (HPLC) analysis revealed the presence of gallic acid, catechin, and chlorogenic acid in type A and type B wax aqueous extracts. The aqueous extracts showed antifungal activity against dermatophytes M. canis and T. rubrum. These results provide evidence that carnauba wax powder extracts might be potential sources of natural antioxidant and antifungal agents.