Antioxidant activity of grains

Epidemiological studies have shown that consumption of whole grains and grain-based products is associated with reduced risk of chronic diseases. The health benefits of whole grains are attributed in part to their unique phytochemical composition. However, the phytochemical contents in grains have been commonly underestimated in the literature, because bound phytochemicals were not included. This study was designed to investigate the complete phytochemical profiles in free, soluble conjugated, and insoluble bound forms, as well as their antioxidant activities in uncooked whole grains. Corn had the highest total phenolic content (15.55 +/- 0.60 micromol of gallic acid equiv/g of grain) of the grains tested, followed by wheat (7.99 +/- 0.39 micromol of gallic acid equiv/g of grain), oats (6.53 +/- 0.19 micromol of gallic acid equiv/g of grain), and rice (5.56 +/- 0.17 micromol of gallic acid equiv/g of grain). The major portion of phenolics in grains existed in the bound form (85% in corn, 75% in oats and wheat, and 62% in rice), although free phenolics were frequently reported in the literature. Ferulic acid was the major phenolic compound in grains tested, with free, soluble-conjugated, and bound ferulic acids present in the ratio 0.1:1:100. Corn had the highest total antioxidant activity (181.42 +/- 0.86 micromol of vitamin C equiv/g of grain), followed by wheat (76.70 +/- 1.38 micromol of vitamin C equiv/g of grain), oats (74.67 +/- 1.49 micromol of vitamin C equiv/g of grain), and rice (55.77 +/- 1.62 micromol of vitamin C equiv/g of grain). Bound phytochemicals were the major contributors to the total antioxidant activity: 90% in wheat, 87% in corn, 71% in rice, and 58% in oats. Bound phytochemicals could survive stomach and intestinal digestion to reach the colon. This may partly explain the mechanism of grain consumption in the prevention of colon cancer, other digestive cancers, breast cancer, and prostate cancer, which is supported by epidemiological studies.     

Procyanidin and catechin contents and antioxidant capacity of cocoa and chocolate products

Cocoa and chocolate products from major brands were analyzed blind for total antioxidant capacity (AOC) (lipophilic and hydrophilic ORAC(FL)), catechins, and procyanidins (monomer through polymers). Accuracy of analyses was ascertained by comparing analyses on a NIST standard reference chocolate with NIST certified values. Procyanidin (PC) content was related to the nonfat cocoa solid (NFCS) content. The natural cocoa powders (average 87% of NFCS) contained the highest levels of AOC (826 +/- 103 micromol of TE/g) and PCs (40.8 +/- 8.3 mg/g). Alkalized cocoa (Dutched powders, average 80% NFCS) contained lower AOC (402 +/- 6 micromol of TE /g) and PCs (8.9 +/- 2.7 mg/g). Unsweetened chocolates or chocolate liquor (50% NFCS) contained 496 +/- 40 micromol of TE /g of AOC and 22.3 +/- 2.9 mg/g of PCs. Milk chocolates, which contain the least amount of NFCS (7.1%), had the lowest concentrations of AOC (80 +/- 10 micromol of TE /g) and PCs (2.7 +/- 0.5 mg/g). One serving of cocoa (5 g) or chocolate (15 or 40 g, depending upon the type of chocolate) provides 2000-9100 micromol of TE of AOC and 45-517 mg of PCs, amounts that exceed the amount in a serving of the majority of foods consumed in America. The monomers through trimers, which are thought to be directly bioavailable, contributed 30% of the total PCs in chocolates. Hydrophilic antioxidant capacity contributed >90% of AOC in all products. The correlation coefficient between AOC and PCs in chocolates was 0.92, suggesting that PCs are the dominant antioxidants in cocoa and chocolates. These results indicate that NFCS is correlated with AOC and PC in cocoa and chocolate products. Alkalizing dramatically decreased both the procyanidin content and antioxidant capacity, although not to the same extent.     

Dietary fibers from mushroom sclerotia. 4. In vivo mineral absorption using ovariectomized rat model

The effect of three novel dietary fibers (DFs) prepared from mushroom sclerotia, namely, Pleurotus tuber-regium, Polyporus rhinocerus, and Wolfiporia cocos, on calcium and magnesium absorption was evaluated in ovariectomized (OVX) rats fed with sclerotial DF based and low Ca (0.3%) diets for 14 days. The animals in the W. cocos DF diet group possessed significantly (p < 0.05) higher levels of cecal total short-chain fatty acids (204 mumol/g of cecal content) and had an acidic pH (5.88) in their cecum when compared with those of the cellulose control group. Such an acidic environment was found to promote the ionization of the unabsorbed Ca and Mg in their cecum, which in turn significantly (p < 0.05) increased the concentrations of cecal soluble Ca (2.56-fold) and Mg (1.22-fold). Besides, the apparent Ca and Mg absorptions of the W. cocos DF group were also significantly (p < 0.05) enhanced (Ca, 16.5%; Mg, 15.3%) together with significantly (p < 0.05) higher serum Ca (3.61 mmol/L) and Mg (1.07 mmol/L) levels when compared with those of the cellulose control group. These data suggest that ingestion of W. cocos DF could improve the overall Ca and Mg absorptions of the OVX rats fed a low Ca diet. The potential use of sclerotial DFs as a functional food ingredient for enhancing mineral absorption is also discussed.     

Antioxidant and antiproliferative activities of Spirulina and Chlorella water extracts

Liver fibrosis is a chronic liver disease that will further develop to cirrhosis if severe damage continues to form. A potential treatment for liver fibrosis is to inhibit activated hepatic stellate cell (HSC) proliferation and, subsequently, to induce HSC apoptosis. It has been reported that antioxidants are able to inhibit the proliferation of HSCs. In this study, the aqueous extract of spirulina was chosen as the source of antioxidant to investigate the inhibitory effect on the proliferation of HSC. The growth inhibitory effects of aqueous spirulina and chlorella extract on human liver cancer cells, HepG2, were also studied and compared in pairs. Results indicated that the total phenol content of spirulina was almost five times greater than that of chlorella (6.86 +/- 0.58 vs 1.44 +/- 0.04 mg tannic acid equivalent/g of algae powder, respectively). The antioxidant activity of spirulina determined by the ABTS*+ method was higher than chlorella (EC50: 72.44 +/- 0.24 micromol of trolox equivalent/g of spirulina extract vs 56.09 +/- 1.99 micromol of trolox equivalent/g of chlorella extract). Results of DPPH* assay also showed a similar trend as the ABTS*+ assay (EC50: 19.39 +/- 0.65 micromol of ascorbic acid equivalent/g of spirulina extract vs 14.04 +/- 1.06 micromol of ascorbic acid equivalent/g of chlorella extract). The aqueous extracts of these two algae both showed antiproliferative effects on HSC and HepG2, but spirulina was a stronger inhibitor than chlorella. Annexin-V staining showed that aqueous extract of spirulina induced apoptosis of HSC after 12 h of treatment. In addition, the aqueous extract of spirulina triggered a cell cycle arrest of HSC at the G2/M phase.     

Major flavonoids in grape seeds and skins: antioxidant capacity of catechin, epicatechin, and gallic acid

Grape seeds and skins are good sources of phytochemicals such as gallic acid, catechin, and epicatechin and are suitable raw materials for the production of antioxidative dietary supplements. The differences in levels of the major monomeric flavanols and phenolic acids in seeds and skins from grapes of Vitis vinifera varieties Merlot and Chardonnay and in seeds from grapes of Vitis rotundifolia variety Muscadine were determined, and the antioxidant activities of these components were assessed. The contribution of the major monomeric flavonols and phenolic acid to the total antioxidant capacity of grape seeds and skins was also determined. Gallic acid, monomeric catechin, and epicatechin concentrations were 99, 12, and 96 mg/100 g of dry matter (dm) in Muscadine seeds, 15, 358, and 421 mg/100 g of dm in Chardonnay seeds, and 10, 127, and 115 mg/100 g of dm in Merlot seeds, respectively. Concentrations of these three compounds were lower in winery byproduct grape skins than in seeds. These three major phenolic constituents of grape seeds contributed <26% to the antioxidant capacity measured as ORAC on the basis of the corrected concentrations of gallic acid, catechin, and epicatechin in grape byproducts. Peroxyl radical scavenging activities of phenolics present in grape seeds or skins in decreasing order were resveratrol > catechin > epicatechin = gallocatechin > gallic acid = ellagic acid. The results indicated that dimeric, trimeric, oligomeric, or polymeric procyanidins account for most of the superior antioxidant capacity of grape seeds.     

Rapid peroxyl radical scavenging capacity (PSC) assay for assessing both hydrophilic and lipophilic antioxidants

This paper reports a simple, rapid, and sensitive assay for assessing peroxyl radical scavenging capacity (PSC) of both hydrophilic and lipophilic antioxidant compounds and food extracts. The assay is based on the degree of inhibition of dichlorofluorescin oxidation by antioxidants that scavenge peroxyl radicals, generated from thermal degradation of 2,2'-azobis(amidinopropane). For hydrophilic antioxidant activity, the dose required to cause a 50% inhibition of the reaction (EC(50)) ranged from 2.41 +/- 0.02 (EGCG) to 21.26 +/- 0.38 microM (ferulic acid). EC(50) values for the hydrophilic antioxidant activity of food extracts ranged from 309.2 +/- 3.63 (apple) to 3345.1 +/- 151.5 micromol of vitamin C equiv/100 g for wheat bran. The EC(50) values for lipophilic antioxidant activity were 1.58 +/- 0.11 (Trolox), 4.35 +/- 0.43 (alpha-tocopherol), 18.94 +/- 0.38 (BHA), and 182.69 +/- 13.7 microM (BHT). Whole grain lipophilic antioxidant activity ranged from 3.49 +/- 0.57 (wheat) to 8.79 +/- 1.98 micromol of alpha-tocopherol equiv/100 g of rice. Hydrophilic antioxidant activity contributed >98% of the total antioxidant activity (hydrophilic plus lipophilic) of whole grains tested. The PSC assay was accurate (86-108% recovery), precise (0.12-11% CV), and reproducible (12% RSD) and produced results comparable to those of similar published assays. The PSC assay can be routinely used to analyze or screen both hydrophilic and lipophilic antioxidants or food extracts and will be a valuable alternative biomarker for future epidemiological studies of chronic diseases.     

Quantification of the group B soyasaponins by high-performance liquid chromatography

High-performance liquid chromatographic methods were developed for the isolation and quantitative determination of the group B soyasaponins, including 2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP)-conjugated soyasaponins alphag, betag, and betaa, and their non-DDMP counterparts, soyasaponins V, I, and II, respectively, with formononetin used as the internal standard. The limits of quantification for soy products were 0.11-4.86 micromol/g. The within-day and between-days assay coefficients of variation were <9.8 and < 14.3%, respectively. The group B soyasaponin concentrations in 46 soybean varieties ranged from 2.50 to 5.85 micromol/g. Soy ingredients (soybean flour, toasted soy hypocotyls, soy protein isolates, textured vegetable protein, soy protein concentrates, and Novasoy) and soy foods (commercial soy milk, tofu, and tempeh) contained the group B soyasaponins from 0.20 to 114.02 micromol/g. There was no apparent correlation between isoflavone and soyasaponin concentrations in the soy products examined.     

Impact of promotion of mango and liver as sources of vitamin A for young children: a pilot study in Burkina Faso

OBJECTIVE: To assess the effectiveness of a behaviour change approach, with or without financial support, in improving vitamin A (VA) intake and serum retinol concentration through mango and liver consumption by children. DESIGN: A parallel design (no control area) was used to assess changes in VA intake and serum retinol over a 15-week period. SETTING AND SUBJECTS: A pilot study was implemented in the Department of Kokologho, a rural area in central west Burkina Faso. One hundred and fifty children aged 2-3 years were randomly selected and assigned to two treatment groups: PA$$ (promotional activities and financial support) and PA (promotional activities). RESULTS: The intervention significantly increased (P < 0.001) total VA intake by 56% in PA$$ and by 50% in PA. VA intake from liver increased significantly (P < 0.001) from 12.7 +/- 23.5 to 155.3 +/- 56.3 microg retinol activity equivalents (RAE) in PA$$ and from 21.6 +/- 29.7 to 135.3 +/- 44.9 microg RAE in PA. Changes in VA intake from liver were significantly higher (P = 0.004) in PA$$ compared with PA. Mean serum retinol concentration increased significantly by 26% (P < 0.001) in PA$$ and 30% (P < 0.001) in PA. Changes in serum retinol concentration (0.13 micromol l(-1) in PA$$ vs. 0.17 micromol l(-1) and in PA) did not differ significantly (P = 0.455) between groups over the intervention. CONCLUSION: Promotional activities on mango and liver intake effectively increased VA intake and serum retinol concentrations. Although an additional beneficial effect of financial support on liver intake was observed, this did not translate into a further increase in serum retinol concentration.     

Bioavailability of pelargonidin-3-O-glucoside and its metabolites in humans following the ingestion of strawberries with and without cream

Plasma and urine were collected over a 24 h period after the consumption by humans of 200 g of strawberries, containing 222 micromol of pelargonidin-3- O-glucoside, with and without cream. The main metabolite, a pelargonidin- O-glucuronide, reached a peak plasma concentration ( C max) of 274 +/- 24 nmol/L after 1.1 +/- 0.4 h ( t max) when only strawberries were ingested. When the strawberries were eaten with cream, the C max was not statistically different but the t max at 2.4 +/- 0.5 h was delayed significantly ( p < 0.001). The pelargonidin- O-glucuronide, along with smaller quantities of other metabolites, was also excreted in urine in quantities corresponding to ca. 1% of anthocyanin intake. The quantities excreted over the 0-24 h collection period were not influenced significantly by cream. However, the 0-2 h excretion of anthocyanin metabolites was significantly lower when the strawberries were eaten with cream, whereas the reverse occurred during with the 5-8 h excretion period. In keeping with these observations, measurement of plasma paracetamol and breath hydrogen revealed that cream delayed gastric emptying and extended mouth to cecum transit time.     

Thermal processing enhances the nutritional value of tomatoes by increasing total antioxidant activity

Processed fruits and vegetables have been long considered to have lower nutritional value than their fresh commodities due to the loss of vitamin C during processing. This research group found vitamin C in apples contributed < 0.4% of total antioxidant activity, indicating most of the activity comes from the natural combination of phytochemicals. This suggests that processed fruits and vegetables may retain their antioxidant activity despite the loss of vitamin C. Here it is shown that thermal processing elevated total antioxidant activity and bioaccessible lycopene content in tomatoes and produced no significant changes in the total phenolics and total flavonoids content, although loss of vitamin C was observed. The raw tomato had 0.76 +/- 0.03 micromol of vitamin C/g of tomato. After 2, 15, and 30 min of heating at 88 degrees C, the vitamin C content significantly dropped to 0.68 +/- 0.02, 0.64 +/- 0.01, and 0.54 +/- 0.02 micromol of vitamin C/g of tomato, respectively (p < 0.01). The raw tomato had 2.01 +/- 0.04 mg of trans-lycopene/g of tomato. After 2, 15, and 30 min of heating at 88 degrees C, the trans-lycopene content had increased to 3.11+/- 0.04, 5.45 +/- 0.02, and 5.32 +/- 0.05 mg of trans-lycopene/g of tomato (p < 0.01). The antioxidant activity of raw tomatoes was 4.13 +/- 0.36 micromol of vitamin C equiv/g of tomato. With heat treatment at 88 degrees C for 2, 15, and 30 min, the total antioxidant activity significantly increased to 5.29 +/- 0.26, 5.53 +/- 0.24, and 6.70 +/- 0.25 micromol of vitamin C equiv/g of tomato, respectively (p < 0.01). There were no significant changes in either total phenolics or total flavonoids. These findings indicate thermal processing enhanced the nutritional value of tomatoes by increasing the bioaccessible lycopene content and total antioxidant activity and are against the notion that processed fruits and vegetables have lower nutritional value than fresh produce. This information may have a significant impact on consumers' food selection by increasing their consumption of fruits and vegetables to reduce the risks of chronic diseases.     

Determination of free flavan-3-ol content in barley (Hordeum vulgare L.) air-classified flours: comparative study of HPLC-DAD/MS and spectrophotometric determinations

The determination of free flavan-3-ol compounds in barley flours (cv. Gotic) and two resulting milling fractions (fine fraction 57% and coarse fraction 43%, w/w) obtained by air classification of dehulled grain is herein described. The determinations were carried out using reversed phase high-performance liquid chromatography coupled with both diode array detection and ESI-MS compared with conventional spectrophotometric determinations (total phenolic compounds by the Folin-Ciocalteu method and free radical scavenging activity with the DPPH assay). Significant correlations among the HPLC quantification, the spectrophotometric data, and the antioxidant capacity of extracts were revealed by Pearson's analysis. Nine flavan-3-ols were identified by HPLC-MS. Catechins and their derivatives were found to make a substantial contribution to the antioxidant power of extracts. The coarse fraction showed larger concentrations of flavan-3-ols (221%) with respect to the fine fraction. This was confirmed by the antioxidant activity of the analyzed flours. The coarse fraction showed the greatest antioxidant activity (1200.1 +/- 66.2 micromol of Trolox equiv/100 g of flour) with respect to whole meal and fine fraction (1025.9 +/- 18.3 and 761.7 +/- 55.3 micromol of Trolox equiv/100 g of flour, respectively).     

Dietary fiber components in yellow passion fruit rind--a potential fiber source

Within the framework for searching for new dietary fiber (DF) sources to remedy the increasing shortage of currently available sources, connected to an upsurge of diabetes, colon cancer, and other diverticular diseases in certain Ivorian areas, yellow passion fruit (Passiflora edulis f. flavicarpa) rind, a byproduct from the juice industry that is available in large quantities, was investigated. The results showed that, as determined by the AOAC enzymatic-gravimetric method, the total dietary fiber (TDF) in alcohol-insoluble material (AIM) from yellow passion fruit (YPF) rind was >73% dry matter of which insoluble dietary fiber accounted for >60% (w/w). The determination of DF using the Saeman hydrolysis method revealed that nonstarchy polysaccharides were the predominant components (approximately 70%, w/w), of which cellulose appeared to be the main fraction. The water holding and oil holding capacities of the fiber-rich material were >3 g of water/g of fiber and >4 g of oil/g of fiber, respectively. All these results lead to the conclusion that DF from YPF rind, prepared as AIM, may be suitable to protect against diverticular diseases.     

Role of disulfide bonds upon the structural stability of an amaranth globulin.

Analysis of globulin-P, the polymerized amaranth globulin, gave a low amount of free sulfhydryls (10.2 +/- 0.5 micromol/g) from which 7 +/- 1 micromol/g was buried inside the molecule. In addition, its disulfide content was high (51 +/- 1 micromol/g) and similar to soybean 11S globulin content. The more exposed disulfide bridges were found to be stabilizing polymers, whereas the less reactive bridges were either linking P(20) and P(30) polypeptides or forming intrachain linkages. It was found that the buried bonds participate in the stabilization of folded polypeptides and the quaternary structure of the globulin. In turn, the dissociation of polymers and disruption of the quaternary structure by the action of 2-mercaptoethanol reverted upon removal of the reducing agent. This demonstrates that the polymerized state and the quaternary structure of the molecules are most favorable from the thermodynamic point of view. The similar content of SH and SS in globulin-P and globulin-S found in this laboratory suggests that the differences between these proteins may be ascribed to other compositional differences.     

Secoisolariciresinol and matairesinol of sea buckthorn (Hippophaë rhamnoides L.) berries of different subspecies and harvesting times

Sea buckthorn (Hippopha? rhamnoides) seeds, berries, and berry fractions are often used as sources of bioactive ingredients for health products. The aim of the present study was to analyze lignans in these fractions of sea buckthorn. Secoisolariciresinol and matairesinol in seeds, fruit pulp/peel, and whole berries of sea buckthorn of three subspecies were analyzed by isotope dilution gas chromatography-mass spectrometry. The total content of the two lignans secoisolariciresinol and matairesinol varied widely from 8 to 139 microg/100 g in fresh berries and from 51 to 319 microg/100 g in dry berries. The content of secoisolariciresinol varied in the range of 34-313 microg/100 g of dry mass in the fruit pulp/peel and 93-355 microg/100 g in dry seeds. The content of matairesinol fell within the range of 3-25 microg/100 g in dry pulp/peel and 1-13 microg/kg in dry seeds. Wild H. rhamnoides ssp. sinensis contained a significantly higher total level of secoisolariciresinol and matairesinol in dry seeds, dry berries, and fresh berries compared with wild ssp. rhamnoides (253 vs 135 microg/100 g, P < 0.01, in seeds; 224 vs 153 microg/100 g, P < 0.05, in dry berries; 71 vs 29 g/100 g, P < 0.01, in fresh berries) and the cultivar of ssp. mongolica (253 vs 112 microg/100 g in seeds, 71 vs 9 microg/100 g in fresh berries). Harvesting dates had a significant influence on the content of the two lignans in seeds, fruit pulp/peel, and whole berries. This is the first report of lignans in sea buckthorn.     

Assessment of cyanogenic potential,nitrate and nitrite contents,and trypsin inhibitor activity of some Nigerian legumes

Edible seeds of seven varieties of legumes commonly consumed by Nigerians in large quantities were evaluated for total protein, cyanogens, nitrate and nitrite contents, and trypsin inhibitor activity using chemical, biochemical, enzymatic, and spectrophotometric methods. All analyzed samples contained cyanogen and nitrate with levels ranging from 5.88 +/- 0.26 to 28.55 +/- 1.32 mg/100 g of DM and from 49.64 +/- 4.60 to 239.42 +/- 7.20 mg/100 g of DM, respectively. Only three of the varieties contained detectable levels of nitrite, which varied from 0.54 +/- 0.01 to 3.19 +/- 0.2 mg/100 g of DM. Trypsin inhibitor activity was detected in all of the samples, ranging from 7.75 to 100.75 micromol/min/mg of protein. Total protein content of the legumes ranged from 17.8 to 28% on a dry weight basis. There was a positive correlation (r = 0.71) between the cyanogenic potential and the nitrate content of the dry seeds. Processing reduced about 78.6-88.8% and 71.0-89.5% of total cyanogen and nitrate contents of the seeds, respectively. Following administration of 5.0-15 mg of NO3 to rats by stomach intubation, analysis of their 24, 48, and 72 h urine showed that only 40% of the administered nitrate appeared in the urine unmetabolized. Processing was shown to drastically reduce these antinutritional factors to very low levels. The health implications of these findings are discussed.     

Phytochemicals and antioxidant activity of milled fractions of different wheat varieties

The health-promoting effects of whole-grain consumption have been attributed in part to their unique phytochemical contents and profiles that complement those found in fruits and vegetables. Wheat is an important component of the human diet; however, little is known about the phytochemical profiles and total antioxidant activities of milled fractions of different wheat varieties. The objectives of this study were to investigate the distribution of phytochemicals (total phenolics, flavonoids, ferulic acid, and carotenoids) and to determine hydrophilic and lipophilic antioxidant activity in milled fractions (endosperm and bran/germ) of three different wheat varieties, two of which were grown in two environments. Grain samples of each of the wheat varieties were milled into endosperm and bran/germ fractions. Each fraction was extracted and analyzed for total phenolics, ferulic acid, flavonoids, carotenoid contents, and hydrophilic and lipophilic antioxidant activities. Total phenolic content of bran/germ fractions (2867-3120 micromol of gallic acid equiv/100 g) was 15-18-fold higher (p < 0.01) than that of respective endosperm fractions. Ferulic acid content ranged from 1005 to 1130 micromol/100 g in bran/germ fractions and from 15 to 21 micromol/100 g in the endosperm fractions. The bran/germ fraction flavonoid content was 740-940 micromol of catechin equiv/100 g. On average, bran/germ fractions of wheat had 4-fold more lutein, 12-fold more zeaxanthin, and 2-fold more beta-cryptoxanthin than the endosperm fractions. Hydrophilic antioxidant activity of bran/germ samples (7.1-16.4 micromol of vitamin C equiv/g) was 13-27-fold higher than that of the respective endosperm samples. Similarly, lipophilic antioxidant activity was 28-89-fold higher in the bran/germ fractions (1785-4669 nmol of vitamin E equiv/g). Hydrophilic antioxidant activity contribution to the total antioxidant activity (hydrophilic + lipophilic) was >80%. In whole-wheat flour, the bran/germ fraction contributed 83% of the total phenolic content, 79% of the total flavonoid content, 51% of the total lutein, 78% of the total zeaxanthin, 42% of the total beta-cryptoxanthin, 85% of the total hydrophilic antioxidant activity, and 94% of the total lipophilic antioxidant activity. Our results showed that different milled fractions of wheat have different profiles of both hydrophilic and lipophilic phytochemicals. These findings provide information necessary for evaluating contributions to good health and disease prevention from whole-wheat consumption.     

Lunasin concentration in different soybean genotypes, commercial soy protein, and isoflavone products

Lunasin is a unique and novel cancer preventive peptide originally isolated from soy. Information on lunasin concentration of soybean cultivars and commercial soy proteins would be useful in developing lunasin-enriched cultivars and soy products. We report the development of an enzyme-linked immunosorbent assay (ELISA) method to identify lunasin and quantify the variations in concentration in 144 selected, diverse soybean accessions from the U.S. Department of Agriculture Soybean Germplasm Collection, several commercially available soy protein fractions and isoflavone-enriched products. With synthetic lunasin and monoclonal antibody, ELISA shows a linear concentration range of 24-72 ng/mL, good reproducibility, a detection limit of 8 ng/mL, and a recovery of 90% on spiked soy samples. Lunasin concentrations in the tested materials range from 0.10 to 1.33 g/100 g flour. Differences that exceeded 100% have been observed among accessions of similar maturity that were grown in the same environment, indicating that genetic differences in soybeans exist for lunasin. The mean of 23 major ancestral lines of U.S. cultivars is similar to the mean of 16 modern cultivars selected to represent the current diversity of the crop, but the highest values were found within the ancestral and exotic accessions. Soy protein concentrate, isolate, and hydrolyzate contain 2.81 +/- 0.30, 3.75 +/- 0.43, and 4.43 +/- 0.59 g lunasin/100 g flour, respectively, while soy flour and soy flakes contain 1.24 +/- 0.22 g lunasin/100 g flour. Isoflavone-enriched products contain very little or no lunasin. The relative mass (M(r)) of lunasin in the samples is 5.45 +/- 0.25 kDa. The wide range of lunasin concentrations within the Glycine max species indicates that the levels of this important bioactive peptide can be genetically manipulated. Furthermore, soy isolates and hydrolyzed soy proteins contain the highest concentrations of lunasin.     

基因型影响磷镁互作下大豆生长及根瘤和菌根性状

  【目的】  明确施加镁肥在不同磷处理的土壤上对不同基因型大豆生长及根瘤和菌根性状的影响。  【方法】  田间试验采用三因素试验设计,设置施P₂O₅ 40 kg/hm2 (P40)和100 kg/hm2 (P100)两个水平,施MgO 0 kg/hm2 (Mg0)和75 kg/hm2 (Mg75)两个水平,磷高效基因型粤春03-3 (YC03-3)和磷低效基因型本地2号(BD2)两个大豆基因型。测定了大豆植株干重、单株结荚数、根系性状、根瘤性状、菌根侵染率以及植株氮、磷、镁含量。  【结果】  P100处理显著增加了两个大豆基因型的植株干重、单株结荚数、总根长、根表面积和体积以及植株氮、磷、镁积累量。施用镁肥,YC03-3在P40和P100处理下植株干重、单株结荚数、植株氮和镁积累量均显著增加,在P100条件下植株磷积累量以及根表面积、根体积、根平均直径显著增加;BD2在P40和P100处理下植株镁积累量显著增加,P40条件下植株氮积累量显著增加。磷和镁处理显著影响大豆与有益微生物的共生。P40条件下,两个大豆基因型的根瘤数和根瘤干重在Mg0和Mg75处理间无显著差异;P100条件下Mg75处理BD2和YC03-3的根瘤数分别较Mg0处理增加了135%和178%,根瘤干重分别增加了308%和197%。Mg0条件下P40处理YC03-3的菌根侵染率较P100增加了31.6%;Mg75条件下P40处理的BD2菌根侵染率较P100增加了15.0%。P40条件下,Mg75提高了BD2菌根侵染率16.3%;P100条件下,Mg75提高了YC03-3菌根侵染率32.1%。主成分分析发现,P100条件下,Mg0与Mg75处理之间差异显著,而P40条件下镁处理之间差异不明显。  【结论】  增施磷肥显著促进了两个大豆基因型的生长,改善了植株氮、磷、镁养分状况。增施镁肥可增加磷高效大豆基因型YC03-3的地上部和根部干重、单株结荚数、植株氮积累量,对磷低效型基因BD2没有显著作用。YC03-3的根瘤密度对施磷和施镁响应较BD2显著。BD2的菌根侵染率在低磷条件下对施镁的反应敏感,而YC03-3的菌根侵染率在P100条件下对施镁反应敏感。由此可见,磷和镁养分之间的互作效应受到大豆基因型的影响。     

Vicianin, prunasin, and beta-cyanoalanine in common vetch seed as sources of urinary thiocyanate in the rat

When young rats were fed a diet containing common vetch seed for 1 month, they excreted in the urine approximately 7 times more thiocyanate than they had ingested. Vicianin, prunasin, and beta-cyanoalanine were identified as principal dietary sources of the excreted thiocyanate. Vicianin was isolated by chromatography and crystallization. Its structure was confirmed by mass spectrometry and by identification of its monosaccharides and aglycon. Prunasin was identified chromatographically by HPLC. The combined seed content of vicianin (0.68 micromol/g) and prunasin (0.16 micromol/g) corresponded to the cyanogen content of the seed (0.91 +/- 0.14 micromol/g; n = 7), determined as cyanide after autolysis. When vicianin was fed, the urinary thiocyanate output was 21% of the ingested amount of vicianin, whereas beta-cyanoalanine yielded a urinary thiocyanate output of < 0.2%. Calculations show that 73% of the thiocyanate can be derived from vicianin and prunasin, with 27% derived from beta-cyanoalanine. High urinary output of thiocyanate has been associated with endocrine and neurological disorders.     

Effect of red mold rice supplements on serum and egg yolk cholesterol levels of laying hens

Monacolin K is a secondary metabolite of Monascus species and reduces cholesterol levels. This research focuses on the effect of adding red mold rice to hens' diet on cholesterol level in egg yolk and on cholesterol, triglyceride, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) levels in serum. Forty-eight Hy-line laying hens of 48 weeks of age were studied by dividing them into four groups. Except for the control group, the feed for three other groups contained 2.0, 5.0, and 8.0% red mold rice (monacolin K concentrations were 0.0145, 0.035, and 0.056%, respectively). The experiment lasted 6 weeks. During this period, egg weight and egg production were recorded every day, and cholesterol, triglyceride, HDL, and LDL in serum were measured weekly as well. The result showed that the cholesterol in eggs produced by experimental groups was lower than that of the control group (0%, 194.14 +/- 8.30; 2%, 167.17 +/- 4.34; 5%, 168.93 +/- 9.38; 8%, 183.02 +/- 7.63 mg/egg; p < 0.05), and the triglyceride (0%, 1494 +/- 178; 2%, 1280 +/- 174; 5%, 1189 +/- 248; 8%, 1381 +/- 218 mg/dL; p < 0.05) and LDL levels (0%, 36.81 +/- 5.53; 2%, 32.25 +/- 7.93; 5%, 30.06 +/- 4.39; 8%, 28.81 +/- 4.16 mg/dL; p < 0.05) were also significantly lowered in the experimental groups. However, the HDL level did not show significant change for either control or experimental groups (0%, 36.06 +/- 3.96; 2%, 36.25 +/- 5.39; 5%, 33.13 +/- 3.68; 8%, 31.44 +/- 4.29 mg/dL; p > 0.05). Besides, the addition of red mold rice also helps to inhibit production of malondialdehyde (MDA) in serum lipid oxidation (0%, 27.42 +/- 0.53; 2%, 25.62 +/- 0.76; 5%, 24.35 +/- 0.59; 8%, 23.63 +/- 0.48 microM; p < 0.05).