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1.
Rye and wheat brans are valuable sources of bioactive compounds, which could be used for the development and commercialization of high added value functional ingredients such as dietary antioxidants. The aim of this study was to evaluate antioxidant potential of rye and wheat bran using different polarity solvents. Cereal brans were ground to four different particle size fractions and extracted at 10.3 MPa pressure and 80 °C temperature by consecutive application of hexane, acetone and methanol:water (80:20%). The highest extract yield was obtained from rye bran using methanol-water; particle size in most cases had a significant effect. Antioxidant potential of extracts was assessed by ABTS+•, DPPH• scavenging, ORAC and total phenols content (TPC) assays. Extraction solvent had a major influence on TPC and antioxidant activity of the extracts. The most active extracts were obtained using methanol:water; rye bran extracts, in general, were stronger antioxidants than wheat bran extracts. For the majority of assays, reduction of particle size resulted in higher antioxidant activity values. However, ABTS+• scavenging was found to decrease by decreasing particle size of rye bran used for extraction.  相似文献   

2.
The reported high phenolic levels in sorghum have led an interest from sorghum breeding programs in developing and identifying germplasms with high phenolic levels, which require screening a large number of samples to find those with the highest levels. Since wet chemistry screening methods are slow, expensive, and destructive, the use of NIR calibration curves could be an alternative. The objectives of this project were to determine the variation range in total phenols, condensed tannins, and 3-deoxyanthocyanidin levels in a diverse set of sorghum genotypes and to assess the predictive value of NIR curves to estimate these compounds in sorghum. A calibration curve to estimate each compound was developed and validated with an independent validation set. Calibration curve correlations for total phenols, condensed tannins, and 3-deoxyanthocyanidins were r = 0.98, 0.97, and 0.99, respectively. Correlations between NIR-predicted values and reference values in the validation set were significant for total phenols (r = 0.93), condensed tannins (r = 0.81) and 3-deoxyanthocyanidin (r = 0.82). These indicated that sufficient variation for these compounds existed within sorghum and that NIR calibration curves could be used to rapidly and non-destructively predict total phenols, condensed tannins, and 3-deoxyanthocyanidins concentrations in whole grain sorghum.  相似文献   

3.
The chestnut bur, a forest waste product from chestnut processing in the food industry, was studied as a potential source of natural antioxidants. Extractions were performed using aqueous solutions of methanol or ethanol. Experiments were planned according to an incomplete 33 factorial design to study the influence of temperature (25-75 °C), time (30-120 min) and solvent concentration (50-90%) on extraction yield and on extract properties: total phenols content, antioxidant activity (using the FRAP, DPPH and ABTS methods) and average molecular weights. All dependent variables were influenced by temperature and solvent concentration whereas the influence of time was almost negligible. Using the response surface methodology the optimal extraction conditions were selected: the highest temperature assayed (75 °C), the lowest solvent concentration (50%) and an extraction time of 75 min for the methanolic extractions and of 30 min for the ethanolic ones. Under those conditions the values predicted for extraction yield and total phenols content were 18.95% and 36.32 g GAE/100 g extract for the methanolic extract and 17.95% and 26.11 g GAE/100 g extract for the ethanolic ones. Methanolic extracts showed superior total phenols content and antioxidant properties and slightly higher extraction yields than ethanolic extracts; however, ethanol is recommended for food applications due to its GRAS (Generally Recognized as Safe) qualification. Gallic acid esters of glucose, ellagic acid and small proportions of quercetin-3-β-d-glucoside, phenolic compounds with demonstrated antioxidant properties, were identified in chestnut bur extracts by RP-HPLC-ESI-TOF.  相似文献   

4.
Chestnut (Castanea sativa) shell and eucalyptus (Eucalyptus globulus) bark, waste products of the food and wood industries, respectively, were analysed as potential sources of antioxidant compounds. The extraction yield, the antioxidant activity and total phenols content of the extracts were greater in chestnut shell than in eucalyptus bark for most of the extraction conditions essayed. Extraction of chestnut shell with a 2.5% Na2SO3 aqueous solution led to the highest extraction yield, 25.6%, total phenols, 13.4 g gallic acid equivalent/100 g oven-dried shell, and FRAP antioxidant activity, 80.7 mmol ascorbic acid equivalent/100 g oven-dried shell. Extraction with methanol:water (50:50, v/v) provided the best results for eucalyptus bark. The antioxidant activity and the total phenols content of the extracts had a positive linear correlation. FTIR spectroscopy confirmed the higher content of phenolic compounds in chestnut shell extracts compared to eucalyptus bark extracts. Chestnut shell extracts were characterized by the presence of high molecular weight species whereas lower molecular weight species were predominant in eucalyptus bark extracts.  相似文献   

5.
This study aimed to evaluate the effect of autohydrolysis temperature of corn residues in the antioxidant activity of the phenolic compounds extracted from the liquid phase. The treatments were carried out at 160, 180, 190 and 200 °C for 30 min in a pressurized batch reactor. Two different methods for phenolic compounds extraction from the autohydrolysis liquors were investigated. For that purpose, solvent extraction with ethyl acetate and acidic precipitation were performed for phenolic compounds recovery. These methods have been compared in terms of extraction yield, physicochemical properties of obtained polyphenols (characterization by Fourier Transform Infrared Spectroscopy, Thermogravimetric Analysis and Gel Permeation Chromatography), total phenolic content, total antioxidant capacity and Trolox equivalent antioxidant capacity (TEAC) values, measured in DPPH (2,2-diphenyl-1-picrylhydrazyl) test system. The maximum phenolic contents ranged from 6.04 mg GAE/100 mg extract in acidic precipitated samples to 16.45 mg GAE/100 mg extract in ethyl acetate soluble fractions. The results indicated that the ethyl acetate fractions possessed the highest antioxidant activity, reaching after 30-60 min the same capacity reported for the reference synthetic antioxidants (Trolox).  相似文献   

6.
Sorghum and millet phenols and antioxidants   总被引：5，自引：2，他引：5  
Sorghum is a good source of phenolic compounds with a variety of genetically dependent types and levels including phenolic acids, flavonoids, and condensed tannins. Most sorghums do not contain condensed tannins, but all contain phenolic acids. Pigmented sorghums contain unique anthocyanins that could be potential food colorants. Some sorghums have a prominent pigmented testa that contains condensed tannins composed of flavan-3-ols with variable length. Flavan-3-ols of up to 8–10 units have been separated and quantitatively analyzed. These tannin sorghums are excellent antioxidants, which slow hydrolysis in foods, produce naturally dark-colored products and increase the dietary fiber levels of food products. Sorghums have high concentration of 3-deoxyanthocyanins (i.e. luteolinidin and apigenidin) that give stable pigments at high pH. Pigmented and tannin sorghum varieties have high antioxidant levels that are comparable to fruits and vegetables. Finger millet has tannins in some varieties that contain a red testa. There are limited data on the phenolic compounds in millets; only phenolic acids and flavones have been identified.  相似文献   

7.
Whole rice grain comprising endosperm, embryo (or germ), and bran has potential beneficial health effects in addition to provision of nutrients. The distribution of phenolic acids and anthocyanins in endosperm, embryo, and bran of white, red, and black rice grains was investigated in this study. The total phenolic content (TPC) was highest in the bran, averaging 7.35 mg GAE/g and contributing 60%, 86% and 84% of phenolics in white, red and black rice. The average TPC of the embryo and endosperm were 2.79 and 0.11 mg GAE/g accounting for 17% and 23%, 4% and 10% and 7% and 9% in white, red and black rice, respectively. The antioxidant capacity determined using DPPH and ORAC displayed a trend similar to TPC. Free/conjugated phenolic acids in white, red and black rice bran accounted for 41%, 65% and 85% of total acids. Bound phenolic acids in rice bran accounted for 90% of total acids in whole grain. Cis-p-coumaric was detected in bound form in bran while cis-sinapic acid was detected in the free/conjugated form in embryo and bran. Cyanidin-3-O-glucoside and peonidin-3-O-glucoside were identified mainly in black rice bran as the total anthocyanins. Cyanindin-3-O-rutinoside was also detected in black rice bran.  相似文献   

8.
Sorghum, a competitive crop due to its agronomical advantages, has gained interest as functional food. Sorghum contains phytochemicals with health benefits and presents some antinutritional compounds such as condensed tannins (CTs). However, it is well known that CTs exhibit antioxidant capacity. This study evaluated the effect of Mexican nixtamalization on total phenols, CTs and antioxidant capacity using two varieties of sorghum. Different conditions of lime (0, 1 and 2%) and cooking time (20, 30 and 40 min) were tested to obtain the best treatment after optimization using multiple linear regression analysis, aiming to minimize the CTs content and maximize the antioxidant capacity. CTs were reduced at 27% in white sorghum and 90%, in red sorghum. Total phenols, flavonoids and antioxidant capacity had an inverse correlation with lime concentration and cooking time. The best conditions for preserving antioxidant capacity with low content of tannins were 1.13% of lime and 31.11 min cooking. The phenolic profile obtained by HPLC showed reductions in gallic and chlorogenic acids only in white sorghum, whereas catechin and quercetin decreased in both varieties. We concluded that nixtamalization effectively reduced CTs to safety intake values, allowing to preserve other phenolic compounds and antioxidant capacity.  相似文献   

9.
The objective of this study was to explore optimal extraction technology of β-glucan from bran of hull-less barley (Qingke in Chinese), and provide scientific basis for industrialization of β-glucan extraction from a commodity waste which is rich in β-glucan. β-Glucan extraction from bran of hull-less barley was performed with an accelerated solvent extraction (ASE) technique and compared with ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), and reflux extraction. The best combination of extraction parameters was obtained through response surface methodology (RSM) with a three-variable-three-level Box-Behnken design (BBD). The optimum extraction parameters were as follow: extraction time for 9 min, extraction temperature at 70 °C, number of cycles at 4, and extraction pressure at 10 MPa. Under these conditions, the experimental extraction yield of β-glucan was 16.39 ± 0.3%, which agreed closely with the predicted value (16.33%). Compared with other extraction methods, ASE produced much higher β-glucan and more environmentally friendly extraction and solvent systems, less extraction discrimination and shorter time, and could be useful to the development of industrial extraction processes.  相似文献   

10.
Monosaccharide analyses were performed, statistically treated and adopted for spelt bran fractions; with regard to the arabinoxylan content. The AX content of the initial spelt bran reached 9.2% with an A/X ratio of 0.39. The initial spelt bran was rich in starch (41.2%) and protein (18.9%). WE- and WU-AXs from micronised spelt bran were extracted after improved enzymic destarching and deproteinisation treatments. WU-AXs were obtained by two successive extractions with 2% alkaline hydrogen peroxide at 60 °C during 4 h. 55% of the AX present in spelt bran was extracted by using the three extraction steps (WE- and WU-AXs), among AX, 13% were WE and 87% were WU. A/X ratios were different depending on the extraction process. WE-AXs were less rich in arabinose than WU-AXs. Each fraction contained two populations of AX. The first one consisted of low MW AX (7–8 kDa). The second population had a higher MW, 310–415 kDa for WU-AXs and 28 kDa for WE-AXs. The extracts had to be purified in order to improve the AX content. Results were compared to those obtained with wheat bran in the literature. This research was, to the best of our knowledge, the first study on AX extraction from spelt bran.  相似文献   

11.
The antioxidant capacity as oxygen radical absorbance capacity (ORAC) and in vitro chemopreventive effect of phytochemicals extracted, partitioned and isolated from the decorticated bran of black Shawaya sorghum (Sorghum bicolor L. Moench) was studied. The chemopreventive effect was evaluated as the induction effect of quinone reductase (QR) using murine hepatoma cells Hepa 1c1c7. The crude methanol extract with an antioxidant capacity of 3.7 μmol Trolox equivalent (TE)/mg was partitioned into 120 fractions with fast centrifugal partition chromatography (FCPC). Fractions with partition coefficients between 0.1 and 0.26 exerted more than 50% of the antioxidant activity of the original crude extract and contained the highest concentration of anthocyanins. No correlation was found for ferulic acid content and ORAC or chemoprevention. A derivative of 7-methoxyapigeninidin at a concentration of 1 μg/ml increased by 31% the QR activity while the original extract reached a maximum of 27% at 40 μg/ml.  相似文献   

12.
Large volumes of condensed distillers solubles (CDS) are generated as by-products, from the sorghum bioethanol industry. The objective was to assess the physico-chemical and bioactive properties of CDS. The unfractionated CDS showed the highest content of phenolic compounds (16 mg GAE/g), antioxidant (522 μM Trolox/g) and antimicrobial activity (MIC 1%(w/v) against Campylobacter spp.) compared to its extracts. The water and methanol extracts also showed high levels of phenolic compounds and antioxidant activity (11.6 and 9.2 mg GAE/g and 349 and 409 μM Trolox/g respectively), followed by ethanol and acetone extractions (7.5 and 6.6 mg GAE/g; 337 and 346 μM Trolox/g respectively). A positive correlation was revealed between total phenol and antioxidant activity. The main phenolic compounds found in the extracts were protocatechuic acid, 4-hydroxybenzoic acid, taxifolin, ferulic acid, cinnamic acid and p-coumaric acid. This study indicates the potential of using CDS as a functional ingredient for other food and feed applications.  相似文献   

13.
Sorghum is a good source of phenolic compounds with a variety of genetically dependent types and levels including phenolic acids, flavonoids, and condensed tannins. Most sorghums do not contain condensed tannins, but all contain phenolic acids. Pigmented sorghums contain unique anthocyanins that could be potential food colorants. Some sorghums have a prominent pigmented testa that contains condensed tannins composed of flavan-3-ols with variable length. Flavan-3-ols of up to 8–10 units have been separated and quantitatively analyzed. These tannin sorghums are excellent antioxidants, which slow hydrolysis in foods, produce naturally dark-colored products and increase the dietary fiber levels of food products. Sorghums have high concentration of 3-deoxyanthocyanins (i.e. luteolinidin and apigenidin) that give stable pigments at high pH. Pigmented and tannin sorghum varieties have high antioxidant levels that are comparable to fruits and vegetables. Finger millet has tannins in some varieties that contain a red testa. There are limited data on the phenolic compounds in millets; only phenolic acids and flavones have been identified.  相似文献   

14.
In this study, Nigella sativa L. oil was extracted using supercritical carbon dioxide with full factorial design to determine the best extraction condition (pressure, temperature and dynamic extraction time) for obtaining an extract with high yield, antioxidant activity and thymoquinone (TQ) quantity. The maximum thymoquinone content in the highest overall yield was achieved through SC-CO2 extraction condition of 150 bar, 40 °C, 120 min with the value of 4.09 mg/ml. The highest SC-CO2 extraction yield was 23.20% which obtained through extraction condition of 350 bar, 60 °C and 120 min. The extraction conducted at 350 bar, 50 °C, 60 min showed the lowest IC50 value (highest antioxidant activity) of 2.59 mg/ml using DPPH radical scavenging activity method. Fatty acid composition of the extracted oil with highest radical scavenging activity was obtained by gas chromatographic analysis.  相似文献   

15.
The potential of chestnut shell and eucalyptus bark extracts as phenol substitutes in the formulation of adhesives, as chrome substitutes in leather tanning and as a source of antioxidants compounds has been studied. The influence of extraction conditions, type and concentration of alkaline compounds (NaOH, Na2SO3 and Na2CO3) and temperature, on extraction yield and on extract characteristics: Stiasny number, tannin content, total phenols content, FRAP (ferric reducing/antioxidant power) antioxidant capacity and molecular weight distribution was analysed. Chestnut shell extracts had much better properties than eucalyptus bark extracts and significantly higher extraction yields were obtained. The increase of temperature from 70 to 90 °C not only increased the extraction yield but also improved the quality of the extracts. For both materials, the 2.5% Na2SO3–90 °C extract, together with the 2.5% NaOH–2.5% Na2SO3–90 °C extract for chestnut shell, showed high extraction yields and the best properties for all the applications proposed.  相似文献   

16.
Maize grains were heated by infrared radiation for 50–100 s, than flaked and milled. The output was set to 110, 115, 120 and 140 °C to determine the effect of temperature on the formation of acrylamide, 5-hydroxymethylfurfural (HMF) and furosine, as well as the level of phenolic compounds in maize flour and its total antioxidant capacity (TAC). Acrylamide and HMF levels were increased as the load of the heat treatment was increased in grains, while furosine concentration was rapidly increased to an apparent maximum (34.96 μg/g) followed by decrease during heating. Acrylamide, as well as HMF variables correlated very well with TAC of heat-treated flour (r2 = 0.98 and 0.86). The process of infrared heating had a great influence on the reduction of phenolic compound contents. However, new antioxidants that were formed as a result of the Maillard reaction increased the total antioxidant capacity of heat-treated maize flour.  相似文献   

17.
In this work, α-amylase was used to treat oat flour with the intent to release phenolic compounds with known antioxidant properties. After methanol extraction, the amounts of nine beneficial phenolic compounds were measured using HPLC. The antioxidant activities of the extracts were assessed using 2,2′-azinobis (3- ethylbenzothiazoline-6-sulfonic acid) (ABTS)，2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and protein oxidative damage protection assays. Compared with heating-only treated oat flour, that treated with α-amylase showed significant increase of extractable total phenolic content (0.46–1.35 μmol gallic acid equivalents per gram oat), total antioxidant capacity, and an increased ability on the protection of protein from oxidative damage. Heating-only increased caffeic acid and vanillin content by 17 (0.03 vs 0.54 μg/g oat) and 1.8 (0.62 vs 1.11 μg/g oat) folds, but slightly increased the content of other phenols. Excluding heating effect, α-amylase treatment increased gallic acid content by 2.6 folds (0.38 vs 1.38 μg/g oat), caffeic acid content by 2.4 (0.54 vs 1.82 μg/g oat) folds, and other phenols by 1.0–1.8 folds. In conclusion, α-amylase treatment can yield oat products containing more extractable phenolic compounds with increased antioxidant capacity.  相似文献   

18.
Antioxidant activity (AA) of durum wheat (Triticum durum Desf.) grains was studied using the innovative LOX/RNO method, able to simultaneously detect different antioxidant mechanisms, and the TEAC assay, one of the most widely used assays. Insoluble-bound and free-soluble phenols, hydrophilic and lipophilic compounds were extracted from eight different whole flour samples; extracts were analyzed for AA and their content in several antioxidants. The LOX/RNO method measured very high AA values, with the highest ones [850–1500 μmol Trolox eq./g whole flour (dry weight)] for insoluble-bound phenolic extracts, highly correlated to total phenolic (r = 0.761, P < 0.001) and ferulic acid (r = 0.816, P < 0.001) contents. Hydrophilic and lipophilic extracts showed lower AA [70-140 and 40–60 μmol Trolox eq./g (dry weight), respectively], highly correlated to flavonoid (r = 0.583, P < 0.01) and protein (r = 0.602, P < 0.01), as well as β-tocotrienol (r = 0.684, P < 0.05) contents, respectively. Interestingly, the LOX/RNO method suggests that insoluble-bound phenolic compounds may exert very strong synergistic interactions within the extract. Contrarily, the TEAC assay did not correlate to any antioxidant content, resulted unable to highlight differences among samples, measured much lower AA values and did not suggest synergism. The use of the LOX/RNO method is useful to unearth new properties of phytochemicals from durum wheat grains, potentially giving health benefits.  相似文献   

19.
The objective of this work was to study the effect of the extraction of phenols by methanol/acetone/water and proteolysis (pepsin 1 hour; trypsin 2 hours) on the nutritional characteristics of unheated rapeseed protein as measured by weight gain, protein intake, net protein ratio, apparent digestibility and absorbed protein. The effect of proteolysis of the methanol/acetone/water extracted rapeseed protein, and the effect of mixing the methanol/acetone/water extract back with the extracted rapeseed protein was also studied. Extraction of phenolic compounds from rapeseed flour significantly improved weight gain, protein intake, net protein ratio and absorbed protein value. However, the mixing of phenolic extract with the extracted rapeseed protein did not appear to have a significant effect.Enzymatic hydrolysis (1 hour with pepsin and 2 hours with trypsin) of the raw material significantly improved the weight gain and protein intake. The combined methanol/acetone/water extraction and protein hydrolysis treatments were beneficial on all nutritional quality parameters of rapeseed protein. These results suggest that the protein-bound phenolic compounds, rather than the free phenolic compounds contribute mainly to the decrease in the nutritional values of proteins associated with phenolic compounds in raw flour before extraction.  相似文献   

20.
High-performance liquid chromatography (HPLC) was used to determine the distribution of phenolic acids in wheat flours produced from five milling extraction rates ranging from 60% to 100% in four cultivars sown in two locations in the 2008–2009 season. Considerable variation was observed in free and bound phenolic acids, and their components in flours with different extraction rates. Most phenolic acids, including the component ferulic, were present in the bound form (94.0%). Ferulic (51.0%) was the predominant phenolic acid in wheat grain, and caffeic (22.8%) and p-coumaric (17.6%) acids were abundant. The phenolic acids and their components were all significantly influenced by effects of cultivar, milling, location, and cultivar × milling interaction, with milling effect being the predominant. The proportions of phenolic compounds varied considerably among milling extractions and cultivars, and their levels depended on both initial grain concentrations and on selection of milling extraction that was incorporated into the final product. The grain phenolic acid concentrations determined ranged from 54 μg g−1 in flour produced at 60% extraction rate to 695 μg g−1 in flour produced at 100% extraction rate, indicating their higher concentrations in bran associated with cell wall materials. Therefore, wholemeal wheat products maximize health benefits and are strongly recommended for use in food processing.  相似文献   

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