Antioxidant properties of methanolic extracts from different parts of Sclerocarya birrea

The methanolic extracts from Sclerocarya birrea leaves (SCL), roots (SCR), barks (SCB), and kernel oil cake (SCK) were examined for radical scavenging capacities and antioxidant activities. The total phenolics of the extracts was determined spectrophotometrically according to the Folin‐Ciocalteau method using gallic acid as standard solution. The total phenolic compounds were found as 304.5, 367.5, 593, 148.0 and 258.0 mg g^‐1 of dry product, respectively. The extracts of SCL, SCR, SCB and SCK were markedly effective in inhibiting the oxidation of linoleic acid and subsequent bleaching of β‐carotene in comparison with the control. Based on oxidation of β‐carotene/linoleic acid, the SCK extract is the most effective followed by SCR, SCL and SCB extract. The antioxidant activity determined by the DPPH (1,1‐diphenyl‐β‐picrylhydrazyl) method revealed that the SCK extract had the highest antioxidant activity on DPPH free radicals followed by SCB, SCR and SCL extracts. The effect of different extracts on the oxidative stability of sunflower oil at 70 °C was tested in the dark and compared with BHA. The oil peroxide values (PVs) were generally lower with the addition of extract in comparison to a control.     

Comparative study of antioxidant and antibacterial properties of the edible mushrooms Pleurotus levis,P. ostreatus,P. pulmonarius and P. tuber‐regium

Comparative studies of functional properties among closely related mushroom species, supported by molecular identification, standard cultivation and extraction protocols, are not well documented. We compared antioxidant and antibacterial properties of standardised hydroalcoholic extracts of four Pleurotus species (P. levis, P. ostreatus, P. pulmonarius and P. tuber‐regium). Antioxidant properties were investigated using DPPH and ABTS radical scavenging capacity, total phenolic content, β‐carotene‐linoleic and ORAC assays. Antibacterial effect was assessed using the microplate method. The functional properties of standardised mushroom extracts were different in species studied. β‐carotene–linoleic acid and ORAC assays showed high antioxidant activity, particularly in P. ostreatus. Pleurotus tuber‐regium exhibited the lowest antioxidant activity in the ORAC assay (3316.0 μmol of trolox equivalent mL^?1), but exerted the most potent bacteriostatic and bactericidal activity. Bacillus subtilis showed a high degree of susceptibility to a very low concentration (3.33 μg mL^?1) of P. levis extract. Remarkable antioxidant and antibacterial properties were found in P. levis and P. tuber‐regium compared to the other species studied that are cultivated commercially.     

Antioxidant properties of commercial soft and hard winter wheats (Triticum aestivum L.) and their milling fractions

The total phenolic content (TPC), total antioxidant activity (TAA), 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) scavenging capacity, inhibition of coupled oxidation in a β‐carotene–linoleate model system, iron(II) chelation activity and inhibition of copper‐induced oxidation of human low‐density lipoprotein (hLDL) cholesterol of 80% ethanolic extracts of soft and hard winter wheat samples and their milling fractions, namely flour, germ, bran and shorts, were investigated. Soft wheat extracts examined demonstrated higher TPC and TAA compared to those of hard wheat extracts. The germ fraction possessed the highest TPC, followed by bran, shorts, whole grain and flour for both wheat types examined. The TAA of both wheat types showed similar results except that shorts performed better than bran in this assay. Free radical scavenging properties of whole grain and milling fractions of both soft and hard wheat samples were examined against DPPH radical. The germ and flour fractions demonstrated the highest and lowest DPPH radical scavenging activity, respectively, among wheat fractions. Wheat extracts were also efficient in preventing bleaching of β‐carotene, which is also known to be free radical mediated. In the iron(II) chelation assay the flour extracts demonstrated excellent activity, while the germ extracts showed a weak activity. The trends were similar in both soft and hard wheat for the iron(II) chelation assay. Wheat extracts also inhibited copper‐induced oxidation of hLDL. In LDL oxidation assay, wheat extracts performed better than the reference antioxidant, ferulic acid. Thus wheat phenolics may serve as effective antioxidative components as measured by in vitro techniques. Copyright © 2005 Society of Chemical Industry     

Antioxidant and antimicrobial activities of Polygonum cognatum Meissn extracts

The antioxidant activities, reducing powers, 2,2‐diphenyl‐l‐picrylhydrazyl (DPPH) radical‐scavenging activities, total phenolic compound contents and antimicrobial activities of ether, ethanol and hot water extracts of Polygonum cognatum Meissn were studied in vitro. The highest antioxidant activity was found in the water extract. However, there were no statistically significant differences among 15 µg ml^?1 extract‐containing samples in linoleic acid emulsion (0.02 M , pH 7.0) during 120 h of incubation (P > 0.05). The reducing power of the water extract was the highest, but its reducing power was markedly lower than that of ascorbic acid. The highest DPPH radical‐scavenging activity was found in the water extract, with 50% DPPH radical scavenging at a concentration of 100 µg ml^?1 dried water extract, while at the same concentration of dried ethanol extract the value was 12%. Surprisingly, no DPPH radical‐scavenging activity was observed in the ether extract. The concentrations of phenolic compounds found were 0.48, 0.50 and 0.01 µg ml^?1 gallic acid equivalent in 10 µg ml^?1 water, ethanol and ether extracts respectively. The ether and ethanol extracts showed antimicrobial activity against Staphylococcus aureus and Bacillus subtilis. The water extract did not show antimicrobial activity against the studied micro‐organisms. © 2002 Society of Chemical Industry     

Comparative study on antioxidant properties of carrot juice stabilised by high‐intensity pulsed electric fields or heat treatments

BACKGROUND: The effect of high‐intensity pulsed electric field (HIPEF) processing (35 kV cm^?1 for 1500 µs using 6‐µs bipolar pulses at 200 Hz) on the antioxidant features (vitamin C, β‐carotene, total phenolic compounds and antioxidant capacity) of carrot juice as well as on peroxidase activity was investigated and compared to the observed in heat pasteurised juices (90 °C for 60 s or 30 s) having the fresh juice as a reference. RESULTS: HIPEF and heat‐treated carrot juices had higher β‐carotene and lower vitamin C contents than the untreated juices immediately after processing. The antioxidant capacity of the juices was significantly modified neither by HIPEF nor by thermal treatments. POD activity decreased drastically (≥93.3%) after processing irrespective of the treatment applied. Vitamin C and β‐carotene content decreased throughout the storage following an exponential trend (R² = 0.801–0.984) with degradation rates between 1.7 × 10^?2 and 3.5 × 10^?2 day^?1. Vitamin C and β‐carotene contents were better maintained in HIPEF‐treated than in heat‐pasteurised juices throughout the storage. Total phenolic content and the antioxidant capacity of the HIPEF‐treated juice did not substantially differ from that of the thermally treated juice for 56 days. CONCLUSION: HIPEF processing may help to achieve fresh‐like carrot juices with increased amounts of health‐related phytochemicals. Copyright © 2009 Society of Chemical Industry     

Antioxidant activity screening of extracts from Sideritis species (Labiatae) grown in Bulgaria

Plant samples from several species and populations of the genus Sideritis (Labiatae) grown in Bulgaria (S scardica, S syriaca and S montana) were extracted with different solvents. Their antioxidant activities were determined by the β‐carotene bleaching test (BCBT), 2,2′‐diphenyl‐1‐picrylhydrazyl (DPPH^?) radical scavenging method and static headspace gas chromatography (HS‐GC) and compared with the antioxidant activity of two reference compounds of different polarity, viz butylated hydroxytoluene (BHT) and rosmarinic acid. The pure reference compounds were applied in a ten‐times lower concentration than the plant extracts. The highest antioxidant activity in the BCBT, close to that of BHT, was observed for the more apolar extracts. The inhibitory effect on β‐carotene bleaching of the polar extracts and rosmarinic acid was much lower than that of BHT. The inhibition of hexanal formation in bulk safflower oil by most of S syriaca and S scardica extracts was as effective as BHT but less so than rosmarinic acid. S montana extracts showed weak antioxidant or even pro‐oxidant properties. Extracts from butanol and from ethyl acetate and the total methanol extracts from all Sideritis plants studied showed a strong radical scavenging activity against DPPH^?, close to that of rosmarinic acid. S montana extracts were, as a whole, slightly weaker radical inhibitors than the extracts from the other two species. The antioxidant activity of Sideritis extracts was attributed to the presence of flavonoid and phenylpropanoid glycosides. Copyright © 2003 Society of Chemical Industry     

Phenolics and antioxidative activities in common beans (Phaseolus vulgaris L)

Six bean cultivars grown in southern Manitoba for 2 years were evaluated for variability in yield of millstreams and phenolic constituents. The ethanolic extract of bean cultivars and millstreams was screened for antioxidant activity using the β‐carotene‐linoleate and the 1, 1‐diphenyl‐2‐picrylhydrazyl (DPPH) in vitro model systems. Cultivar was the main source of variation for yield of millstreams, content of phenolic compounds and antioxidant activities. Phenolic compounds in cultivars varied from 3.3 to 16.6 mg catechin equivalent and from 0.15 to 0.32 mg cyanidin‐3‐glucoside equivalent g^?1 bean for total phenolic and anthocyanin contents, respectively. The bean cultivars exhibited antioxidant activity (AA) of 10–46% inhibition of lipid peroxidation in the linoleate and 0.4–1.3 trolox equivalent antioxidant capacities (TEAC) in the DPPH model systems. The hull millstream with maximum concentration of phenolic compounds exhibited the strongest antioxidant activity of 383 µM trolox equivalent g^?1 hull. Total phenolic content, alone or in combination with other phenolic constituents, is a potential candidate as a selection criterion for antioxidant activity in beans. Copyright © 2005 Society of Chemical Industry     

Porosity and Water Activity Effects on Stability of Crystalline β‐Carotene in Freeze‐Dried Solids

Abstract: Stability of entrapped crystalline β‐carotene as affected by water activity, solids microstructure, and composition of freeze‐dried systems was investigated. Aliquots (1000 mm³, 20% w/w solids) of solutions of maltodextrins of various dextrose equivalents (M040: DE6, M100: DE11, and M250: DE25.5), M100‐sugars (1:1 glucose, fructose and sucrose), and agar for gelation with dispersed β‐carotene were frozen at ?20, ?40, or ?80 °C and freeze‐dried. Glass transition and α‐relaxation temperatures were determined with differential scanning calorimetry and dynamic mechanical analysis, respectively. β‐Carotene contents were monitored spectrophotometrically. In the glassy solids, pore microstructure had a major effect on β‐carotene stability. Small pores with thin walls and large surface area allowed β‐carotene exposure to oxygen which led to a higher loss, whereas structural collapse enhanced stability of β‐carotene by decreasing exposure to oxygen. As water plasticized matrices, an increase in molecular mobility in the matrix enhanced β‐carotene degradation. Stability of dispersed β‐carotene was highest at around 0.2 a_w, but decreasing structural relaxation times above the glass transition correlated well with the rate of β‐carotene degradation at higher a_w. Microstructure, a_w, and component mobility are important factors in the control of stability of β‐carotene in freeze‐dried solids Practical Application: β‐Carotene expresses various nutritional benefits; however, it is sensitive to oxygen and the degradation contributes to loss of nutritional values as well as product color. To increase stability of β‐carotene in freeze‐dried foods, the amount of oxygen penetration need to be limited. The modification of freeze‐dried food structures, for example, porosity and structural collapse, components, and humidity effectively enhance the stability of dispersed β‐carotene in freeze‐dried solids.     

Chemical,antioxidant and antibacterial study of Brazilian fruits

In this study, the antioxidant capability, total phenolic content and antimicrobial activity of ethanolic extracts of seven fruits from the Brazilian Atlantic Forest were evaluated. The conditions for the extraction of crude phenolics from the fruits were determined using an experimental factorial design. Total phenolic content, 1,1‐diphenyl‐2‐picrylhydrazyl radical (DPPH^?) scavenging activity and β‐carotene‐linoleic acid couple oxidation assays were used to evaluate the antioxidant properties of the extracts. In addition, antimicrobial activity was screened using two Gram‐negative bacteria (Escherichia coli and Klebsiella pneumoniae) and one Gram‐positive bacterium (Staphylococcus aureus). All native fruits assayed in this study have high potential as natural antioxidant sources. Among the seven fruits evaluated, Jabuticaba and Uvaia had the highest antioxidant activity in the DPPH^? and of β‐carotene‐linoleic acid coupled oxidation assays. In the biological assay, K. pneumoniae was the most sensitive microorganism to the fruit extracts, and the Jabuticaba extract had a slight inhibitory effect against this Gram‐positive bacterium.     

Effects of microwave and hot‐air drying methods on colour, β‐carotene and radical scavenging activity of apricots

The effects of drying by microwave and convective heating at 60 and 70 °C on colour change, degradation of β‐carotene and the 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH) scavenging activity of apricots were evaluated. Microwave heating reduced significantly the drying time (up to 25%), if compared with convective one, also owing to the higher temperature reached during the last phase of the process, as monitored by infrared thermography. Colour changes of apricot surface, described with lightness and hue angle, in both drying methods followed a first‐order reaction (0.927 ≤ R² ≤ 0.996). The apricots dried by microwave were less affected by the darkening phenomena. The evolution of β‐carotene in fresh apricots (61.2 ± 5.6 mg kg^?1 d.w.) during the drying highlighted a wider decrease (about 50%) when microwave heating was employed for both the temperatures used. Radical scavenging activity increased (P < 0.05) in all dried samples except for hot‐air dried apricots at 60 °C.     

Physiological changes, phenolic content and antioxidant activity of Salvia officinalis L. grown under saline conditions

BACKGROUND: Hydroponic culture was used to investigate the effect of NaCl concentrations on the growth, nutrient uptake, phenolic content and antioxidant activity of Salvia officinalis L. leaves. The antioxidant capacity of the methanolic extract of S. officinalis was evaluated by using 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging test and β‐carotene‐linoleic acid bleaching assay. Physiological and biochemical parameters of S. officinalis were assessed after 4 weeks of salt treatment with 0, 25, 50, 75 and 100 mmol L^?1 NaCl. RESULTS: Plant growth exhibited a reduction of 61% at 100 mmol L^?1 NaCl. Assessment of Na⁺, K⁺ and Ca²⁺ and water contents of shoots and roots showed that S. officinalis is able to regulate Na⁺ concentration by active compartmentation in vacuoles. Salvia officinalis phenolics were increased in response to salinity at the threshold of 75 mmol L^?1 NaCl. This herb was also found to be able to achieve important DPPH^? quenching activity and to inhibit the β‐carotene‐linoleic acid bleaching notably enhanced by salt treatment. It is interesting to highlight the correlation between the phenolic and antioxidant activity, suggesting the involvement of these compounds in this activity. CONCLUSION: Salvia officinalis treated with 75 mmol L^?1 NaCl constitutes a potential source for production of secondary metabolites useful in several applications. Copyright © 2011 Society of Chemical Industry     

Changes in bioactive compounds and antioxidant activity during convective drying of murta (Ugni molinae T.) berries

Murta (Ugni molinae T.) berries were air‐dried at five temperatures (40, 50, 60, 70 and 80 °C), and the changes in β‐carotene, phenolic acids, total phenolic and flavonoid contents and antioxidant capacities (DPPH and ORAC) were investigated. The berries showed a high content of β‐carotene, which decreased during drying temperature between 40 °C and 80 °C. Free and bound phenolic acids were also determined, showing gallic acid to be the prevalent phenolic acid. Total phenolic and flavonoid contents in the dried berries showed a higher decrease at lower temperature due to longer drying time. The radical‐scavenging activity also showed higher antioxidant activity at higher drying temperatures (70–80 °C) than at lower drying temperatures (40–50 °C). Total phenolic content (TPC) and flavonoids showed good correlation with antioxidant capacity. Murta berries proved to be an excellent source of antioxidants and bioactive compounds and are therefore a potential ingredient for new functional food products.     

Phenolic Content and Antioxidant Activity of Primitivo Wine: Comparison among Winemaking Technologies

ABSTRACT: The aim of this study was to assess the influence of 9 winemaking technologies (traditional, delestage, saignée, delayed punching‐down, addition of grape seed tannins, addition of ellagic‐skin‐seed tannins, heating of must‐wine, cryo‐maceration, and prolonged maceration) on the phenolic content and antioxidant activity of Primitivo musts and wines. Three methods for the determination of the antioxidant activity were compared: DPPH, β‐carotene bleaching assay, and ABTS. Oenological parameters and composition of the phenolic fraction of 1‐y‐aged wines was also determined. The addition of tannins allowed the increase of the phenolic content of musts and wines in a greater amount than the other technologies. The results concerning the antioxidant activity depended on the method applied. Concerning musts, the DPPH assay did not highlight great differences among technologies, whereas the addition of tannins allowed the obtainment of the highest antioxidant activity according to β‐carotene and ABTS assays. The wine aging determined an increase of the antioxidant activity, independently on the method applied. Wine obtained through traditional technology, saignée, and addition of tannins showed the highest antioxidant activities according to DPPH and β‐carotene. The highest correlation coefficients (0.961 and 0.932) were calculated between phenolic content and ABTS values of musts whereas the lowest values (0.413 and 0.517) were calculated between phenolic content and ABTS values of wines. Wines produced through traditional technology were the richest in anthocyanins. The addition of tannins allowed to obtain high content in monomeric anthocyanins, flavonoids, flavans reactive to vanillin, and coumaroylated malvidin and a low content in acetylated malvidin. Practical Applications: It is well known that a moderate consumption (equivalent to 2 glasses per day) of red wine is actually recommended since it appears associated with a decreased incidence of cardiovascular diseases. The mechanisms involved in this protective effect are not completely understood although they appear related to the presence of phenolic compounds. To increase the intake of these compounds without increase of the wine consumption, it is necessary to improve their extraction during maceration. This study could represent a helpful tool for wineries aimed to know the way to increase the antioxidant content of their wines, thus changing them in functional beverages and prolonging their shelf life.     

Tomato peel drying and carotenoids stability of the extracts

Tomato peels were firstly dried by different methods (hot air, freeze‐drying, and fluidized bed drying) to evaluate the recovery of lycopene, β‐carotene and DPPH radical scavenging activity. Comparison of the results showed that hot air drying at 50 °C was a suitable method and alternative to freeze‐drying to preserve carotenoids compounds and antioxidant activity in tomato peels. Then, ethanol/ethyl acetate (1:1) extracts from tomato peel, previously dried at 50 °C by hot air, were submitted to heat (100 °C) and light treatment (1000 lumen) to evaluate their stability as natural food dyes. Heating of the extracts caused a progressive reduction of total carotenoids, up to about 30% after 250 min of treatment, whereas the colour at the end of heat treatment showed small changes, with an overall colour difference (?E) equal to 7. Fluorescent lighting treatment showed an almost total degradation of carotenoids in the extracts after 48 h combined with a fading colour.     

A comparative study on the antioxidative and anti‐allergic activities of fresh and aged black garlic extracts

The antioxidative and anti‐allergic activities of fresh and aged black garlic extracts were investigated. The garlic samples were extracted with 70% ethanol (v/v) and the total phenolic content was measured. The antioxidant capacity of extracts was assessed by determining the scavenging activities on 1,1‐diphenyl‐2‐picrylhydrazyl and hydroxyl radicals, ferricyanide reducing power, ferrous ion‐chelating ability and inhibitory effect on linoleic acid peroxidation. The anti‐allergic activity of extracts was analysed by measuring their inhibitory effects against β‐hexosaminidase release. The aged black garlic exhibited significantly higher phenolic content and greater antioxidative activity than fresh garlic. Both garlic extracts showed strong antioxidant capacity in a dose‐dependent manner. On the other hand, a considerably higher suppression of β‐hexosaminidase release was found in fresh garlic extract at lower concentration compared with that of the black garlic. Results of this study illustrate that ageing of garlic could enhance its antioxidant capacity, but could decrease its anti‐allergic activity.     

Effects of Food Processing on Blueberry Antiproliferation and Antioxidant Activity

Cultivated highbush (Vaccinium corymbosum L.) and wild lowbush (Vaccinium angustifolium Ait.) blueberries are excellent sources of phytochemicals that are believed to have significant biological activity. The objective of this study was to determine whether incorporation of blueberries into food products affects their phenolic content or antioxidant and antiproliferation activity. Several blueberry fruit‐containing products including fresh, individually quick frozen (IQF), freeze‐dried, spray‐dried, heat‐dried, cooked, juice concentrate, pie filling, and jam were fractionated to remove sugars and isolate groups of phytochemicals based on solubility. The fractions were analyzed for total phenolics and assayed for ferric reducing antioxidant power (FRAP) antioxidant activity, 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activity, and hepa‐1c1c7 antiproliferative activities. For both cultivated and wild berries, fresh and IQF berries had the highest total phenols, antioxidant activity, and antiproliferation activity. Whole freeze‐dried wild blueberries also retained significant antiproliferative activity in 2 fractions eluted with acetone (fraction 4, 4% of control cell growth at 20 (μg/mL) and 50% aqueous acetone (fraction 5, 69% of control cell growth at 20 (μg/mL) and ranked close to the activities recorded for fresh (30% of control cell growth at 20 (μg/mL for fraction 5) and IQF whole fruit (27% of control cell growth at 20 (μg/mL for fraction 5). Products that were heat‐processed retained most of the antioxidant activity and total phenolics found in unprocessed whole fruit. However, the heat‐treated products lacked or had diminished antiproliferation activity, suggesting that although products may be high in phenolic compounds and antioxidant activity, some forms of bioactivity may be compromised by harsh processing methods.     

Compositions and antioxidant properties of protein hydrolysates from the skins of four carp species

Compositions and antioxidant properties of protein hydrolysates prepared from four carp skins: black carp, grass carp, silver carp and bighead carp, using pepsin, with a degree of hydrolysis (DH) of 6–15%, were investigated. The yield of freeze‐dried hydrolysates was in the range of 54–62 g/100 g (dry skin). The content of protein and ash in four freeze‐dried hydrolysates was 72–81% and 8–17%, respectively. All hydrolysates contained high amount of hydrophobic amino acid residues (389–480 residues/1000 residues). Meanwhile, their antioxidant properties were evaluated by in vitro assays. The results revealed that all hydrolysates possessed potent antioxidant activities and showed dose dependency as the activity increased with sample concentration, capable of scavenging 72–88% of DPPH and 61–69% of hydroxyl radicals, respectively, at the highest tested concentration. The hydrolysates exhibited high reducing power and β‐carotene–linoleic acid oxidation inhibition. Among the four hydrolysates, the hydrolysate derived from bighead carp skin was superior to others in terms of yield, DH and antioxidant activities.     

Chemical composition and antioxidant and radical‐scavenging activities of Periploca laevigata root bark extracts

BACKGROUND: The root powder of Periploca laevigata is used for preparing soft drinks and as an aromatic in Tunisia. The infusion or decoction of its root bark has widespread use in folk medicine. The plant is used to treat digestive disorders and hypertensive effects as well as other health problems. RESULTS: The antioxidant activities of extracts of P. laevigata root bark obtained with solvents of different polarity were investigated using assays of 1,1‐diphenyl‐2‐picrylhydrazyl radical‐scavenging activity, ferric‐reducing capacity, β‐carotene‐bleaching ability, hydroxyl radical‐scavenging activity and lipid peroxidation inhibition. The methanol extract, with the highest amount of total phenolics and flavonoids, showed the highest antioxidant activities in all assays, followed by the water extract. Gas chromatography/mass spectrometry was used to determine the composition of the water and methanol extracts. Thirty‐four compounds were identified in the methanol extract, with proflavine (516.2 g kg^?1 dry matter (DM)) and 4‐methoxysalicylaldehyde (198.3 g kg^?1 DM) being the most abundant. Sixteen compounds were identified in the water extract, of which 4‐hydroxy‐3‐methoxyphenethylene glycol (351.2 g kg^?1 DM) was the main component. CONCLUSION: As far as is known, this is the first report on the chemical composition and biological activities of phenolic extracts from P. laevigata. The results of the study indicate that the root bark of this plant might be a good candidate for further investigation in developing new antioxidants. Copyright © 2009 Society of Chemical Industry     

Phenolic extracts of cachaça aged in different woods and quantifying antioxidant activity and antifungal properties

The antioxidant and antifungal activities of the phenolic compounds in different alcoholic extracts of aged cachaça were evaluated. The physico‐chemical analyses were performed in the Laboratório de Qualidade de Aguardente of the Universidade Federal de Lavras according to the methods of the Ministério Agricultura Pecuária e abastecimento. Total phenol content was determined by the Folin–Ciocalteu method, quantification of these compounds was performed by HPLC and antioxidant activities were determined by methods involving inhibition of the DPPH (1,1‐diphenyl‐2 picrylhydrazyl) radical, the β‐carotene/linoleic acid system, ABTS (2,2 azinobis‐[3‐ethyl‐6‐benzothiazolinesulfonic acid]) radical, reducing power and thiobarbituric acid. Determination of antifungal activity was accomplished through the technique of dissemination in discs using Aspergillus carbonarius, Aspergillus niger, Aspergillus flavus, Penicillium commune and Penicillium cladosporoides fungi at the Laboratório de Micologia de Alimentos. The values obtained for the phenolic compounds ranged from 0.41 to 9.69 mg L^?1; syringaldehyde, vanillic acid and gallic acid were predominant. A satisfactory antioxidant activity was observed in all of the tests with the alcoholic extracts. A moderate activity against P. commune and P. cladosporoides, but no inhibition of the growth of A. carbonarius, A. niger or A. flavus was observed. Copyright © 2016 The Institute of Brewing & Distilling     

In vitro bioaccessibility of β‐carotene in dried carrots pretreated by different methods

The effects of selected pretreatment methods, i.e. soaking in citric acid, blanching in water and blanching in citric acid, as well as hot‐air drying (at 70, 80 and 90 °C), on the retention and relative in vitro bioaccessibility of β‐carotene in dried carrots were investigated. The results indicated that the selected pretreatments and drying could enhance the relative bioaccessibility of β‐carotene in dried carrots. The relative bioaccessibility of β‐carotene in dried carrots increased to 47–73%, while the values in the fresh (13%) and dried untreated (31–47%) carrots were lower. Although significant losses of β‐carotene occurred during both the pretreatment and drying processes, bioaccessible β‐carotene contents of dried pretreated carrots were in a similar order to those of the fresh carrots, indicating the ability and hence the benefit of appropriate pretreatment and drying processes in maintaining the nutritive quality of a food product.