Showing papers in "Journal of Agricultural and Food Chemistry in 1999"
TL;DR: High activities were found in tree materials, especially in willow bark, spruce needles, pine bark and cork, and birch phloem, and in some medicinal plants including heather, bog-rosemary, willow herb, and meadowsweet and potato peel and beetroot peel extracts showed strong antioxidant effects.
Abstract: The antioxidative activity of a total of 92 phenolic extracts from edible and nonedible plant materials (berries, fruits, vegetables, herbs, cereals, tree materials, plant sprouts, and seeds) was examined by autoxidation of methyl linoleate. The content of total phenolics in the extracts was determined spectrometrically according to the Folin-Ciocalteu procedure and calculated as gallic acid equivalents (GAE). Among edible plant materials, remarkable high antioxidant activity and high total phenolic content (GAE > 20 mg/g) were found in berries, especially aronia and crowberry. Apple extracts (two varieties) showed also strong antioxidant activity even though the total phenolic contents were low (GAE < 12.1 mg/g). Among nonedible plant materials, high activities were found in tree materials, especially in willow bark, spruce needles, pine bark and cork, and birch phloem, and in some medicinal plants including heather, bog-rosemary, willow herb, and meadowsweet. In addition, potato peel and beetroot peel extracts showed strong antioxidant effects. To utilize these significant sources of natural antioxidants, further characterization of the phenolic composition is needed.
3,612 citations
TL;DR: The increase observed in antioxidant capacity through postharvest phenolic synthesis and metabolism suggested that commercially feasible technologies may be developed to enhance the health functionality of small fruit crops.
Abstract: Fresh strawberries (Fragaria × ananassa Duch.), raspberries (Rubus idaeus Michx.), highbush blueberries (Vaccinium corymbosum L.), and lowbush blueberries (Vaccinium angustifolium Aiton) were stored at 0, 10, 20, and 30 °C for up to 8 days to determine the effects of storage temperature on whole fruit antioxidant capacity (as measured by the oxygen radical absorbing capacity assay, Cao et al., Clin. Chem. 1995, 41, 1738−1744) and total phenolic, anthocyanin, and ascorbate content. The four fruit varied markedly in their total antioxidant capacity, and antioxidant capacity was strongly correlated with the content of total phenolics (0.83) and anthocyanins (0.90). The antioxidant capacity of the two blueberry species was about 3-fold higher than either strawberries or raspberries. However, there was an increase in the antioxidant capacity of strawberries and raspberries during storage at temperatures >0 °C, which was accompanied by increases in anthocyanins in strawberries and increases in anthocyanins and ...
992 citations
TL;DR: The total contents of these flavonols in cranberry, bog whortleberry, lingonberry, black currant, and crowberry were higher than those in the commonly consumed fruits or vegetables, except for onion, kale, and broccoli.
Abstract: The amounts of quercetin, myricetin, and kaempferol aglycons in 25 edible berries were analyzed by an optimized RP-HPLC method with UV detection and identified with diode array and electrospray ionization mass spectrometry detection. Sixteen species of cultivated berries and nine species of wild berries were collected in Finland in 1997. Quercetin was found in all berries, the contents being highest in bog whortleberry (158 mg/kg, fresh weight), lingonberry (74 and 146 mg/kg), cranberry (83 and 121 mg/kg), chokeberry (89 mg/kg), sweet rowan (85 mg/kg), rowanberry (63 mg/kg), sea buckthorn berry (62 mg/kg), and crowberry (53 and 56 mg/kg). Amounts between 14 and 142 mg/kg of myricetin were detected in cranberry, black currant, crowberry, bog whortleberry, blueberries, and bilberry. Kaempferol was detected only in gooseberries (16 and 19 mg/kg) and strawberries (5 and 8 mg/kg). Total contents of these flavonols (100−263 mg/kg) in cranberry, bog whortleberry, lingonberry, black currant, and crowberry were hi...
693 citations
TL;DR: One cup of tea of usual strength (1-2%), can provide the same potential for improving antioxidant status as around 150 mg of pure ascorbic acid (vitamin C).
Abstract: This study aimed to compare in vitro antioxidant power of different types of tea (Camellia sinensis). The ferric reducing/antioxidant power (FRAP) assay was used to measure the total antioxidant power of freshly prepared infusions of 25 types of teas. Results showed that different teas had widely different in vitro antioxidant power and that the antioxidant capacity was strongly correlated (r = 0. 956) with the total phenolics content of the tea. Expressed as micromol of antioxidant power/g of dried tea leaves, values ranged as 132-654 micromol/g for black ("fermented") teas, 233-532 micromol/g for Oolong ("semifermented") teas, and 272-1144 micromol/g for green ("nonfermented") teas. One cup of tea of usual strength (1-2%), therefore, can provide the same potential for improving antioxidant status as around 150 mg of pure ascorbic acid (vitamin C).
671 citations
TL;DR: Vicultural practices that increased cluster sun exposure generally led to higher phenolics and color density of wines, whereas changing yeasts used for fermentation had minimal effects.
Abstract: Changes in phenolics (anthocyanins, flavonols, tartaric esters, and total phenolics) during ripening of grapes and in phenolics and color during vinification and aging of Cabernet Franc, Merlot, and Pinot Noir wines were studied. Anthocyanins in grape skins showed variations in accumulation pattern, concentration, and distribution depending on variety and to a lesser extent on season. During vinification, colorless phenolics increased during alcoholic fermentation, reached maximum values at pressing, and remained stable during malolactic fermentation and subsequent storage. Anthocyanins and color density, on the other hand, increased during the early stages of alcoholic fermentation, reached maximum values 2-3 days after the start of fermentation, decreased during malolactic fermentation, and slowly declined during subsequent storage. Viticultural practices that increased cluster sun exposure generally led to higher phenolics and color density of wines, whereas changing yeasts used for fermentation had minimal effects.
592 citations
TL;DR: Wide variations in glucosinolate content among genotypes suggest differences in their health-promoting properties and the opportunity for enhancement of their levels through genetic manipulation.
Abstract: Glucosinolates were evaluated in 5 groups and 65 accessions of Brassica oleracea (50 broccoli, 4 Brussels sprouts, 6 cabbage, 3 cauliflower, and 2 kale) grown under uniform cultural conditions. Glucosinolates and their concentrations varied among the different groups and within each group. The predominant glucosinolates in broccoli were 4-methylsulfinylbutyl glucosinolate (glucoraphanin), 3-butenyl glucosinolate (gluconapin), and 3-indolylmethyl glucosinoate (glucobrassicin). Glucoraphanin concentration in broccoli ranged from 0.8 micromol g(-1) DW in EV6-1 to 21.7 micromol g(-1) DW in Brigadier. Concentrations of the other glucosinolates in broccoli varied similarly over a wide range. In Brussels sprouts, cabbage, cauliflower, and kale, the predominant glucosinolates were sinigrin (8.9, 7.8, 9.3, and 10.4 micromol g(-1) DW, respectively) and glucobrassicin (3.2, 0.9, 1.3, and 1.2 micromol g(-1) DW, respectively). Brussels sprouts also had significant amounts of gluconapin (6.9 micromol g(-1) DW). Wide variations in glucosinolate content among genotypes suggest differences in their health-promoting properties and the opportunity for enhancement of their levels through genetic manipulation.
589 citations
TL;DR: The antioxidant activity of four derivatives of benzoic acid was systematically compared with the activity of the four homologous derivatives of cinnamic acid, and the dihydroxy acids had an antioxidant capacity equal to or higher than that of the p-hydroxydimethoxy acids in the LDL system.
Abstract: The antioxidant activity of four derivatives of benzoic acid was systematically compared with the activity of the four homologous derivatives of cinnamic acid. The couples of compounds differed for the kind of aromatic substitution (p-hydroxy, p-hydroxymethoxy, p-hydroxydimethoxy, dihydroxy). The antioxidant activity was measured using (i) a competition kinetic test, to measure the relative capacity to quench peroxyl radical and (ii) the in vitro oxidative modification of human low-density lipoprotein (LDL), initiated by 2,2'-azobis(amidinopropane) dihydrochloride or catalyzed by Cu(II). In both models, cinnamic acids were more efficient than their benzoic counterparts. As for the influence of the aromatic substitution, in the kinetic test the antioxidant activity increased in the sequence p-hydroxy < p-hydroxymethoxy < dihydroxy < p-hydroxydimethoxy. In contrast, in the LDL system, the dihydroxy acids had an antioxidant capacity equal to or higher than that of the p-hydroxydimethoxy acids.
563 citations
TL;DR: The results obtained by the DMPD method are very similar to those obtained on the same samples when the radical cation of 2, 2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) (Miller et al., 1996) was used.
Abstract: A novel method for measuring the antioxidant activity using N, N-dimethyl-p-phenylenediamine (DMPD) was developed. The radical cation of this compound gives a stable colored solution and a linear inhibition of color formation can be observed in the presence of 0. 2-11 microg of TROLOX. The experimental protocol, which is rapid and inexpensive, ensures sensitivity and reproducibility in the measure of antioxidant activity of hydrophilic compounds. The effectiveness of the DMPD method on real foods was verified by evaluating the antioxidant ability of wine samples coming from different areas of Campania, Italy. Antioxidant capacity of wines is strictly related to the amount of phenolic compounds. The results obtained by the DMPD method are very similar to those obtained on the same samples when the radical cation of 2, 2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) (Miller et al., 1996) was used.
544 citations
TL;DR: In this article, turmeric oleoresin was extracted from the mother liquor using hexane at 60 degrees C, and the hexane extract was separated into three fractions using silica gel column chromatography.
Abstract: Curcumin, the yellow color pigment of turmeric, is produced industrially from turmeric oleoresin. The mother liquor after isolation of curcumin from oleoresin contains approximately 40% oil. The oil was extracted from the mother liquor using hexane at 60 degrees C, and the hexane extract was separated into three fractions using silica gel column chromatography. These fractions were tested for antibacterial activity by pour plate method against Bacillus cereus, Bacillus coagulans, Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Fraction II eluted with 5% ethyl acetate in hexane was found to be most active fraction. The turmeric oil, fraction I, and fraction II were analyzed by GC and GC-MS. ar-Turmerone, turmerone, and curlone were found to be the major compounds present in these fractions along with other oxygenated compounds.
509 citations
TL;DR: This qualitative report confirms the presence of a complex series of procyanidins in raw cocoa and certain chocolates using HPLC/MS techniques and application of this method for qualitative analysis of proanthocyanidin in other food products is investigated.
Abstract: Monomeric and oligomeric procyanidins present in cocoa and chocolate were separated and identified using a modified normal-phase high-performance liquid chromatography (HPLC) method coupled with on-line mass spectrometry (MS) analysis using an atmospheric pressure ionization electrospray chamber. The chromatographic separation was achieved using a silica stationary phase in combination with a gradient ascending in polarity. This qualitative report confirms the presence of a complex series of procyanidins in raw cocoa and certain chocolates using HPLC/MS techniques. Although both cocoa and chocolate contained monomeric and oligomeric procyanidin units 2-10, only use of negative mode provided MS data for the higher oligomers (i.e., >pentamer). Application of this method for qualitative analysis of proanthocyanidins in other food products and confirmation of this method as a reliable quantitative tool for determining levels of procyanidins in cocoa, chocolate, and other food products are currently being investigated.
479 citations
TL;DR: The usefulness of the in vitro digestion process as a rapid and cost-effective model for screening the bioavailability of carotenoids from meals is supported.
Abstract: The objective of this study was to develop a model for assessing the bioavailability of carotenoids from meals using an in vitro digestion procedure. A meal was prepared using baby food carrots, spinach, and a meat, plus tomato paste. The aqueous fraction was isolated from digesta to determine the quantity of carotenoids transferred from the food to micelles. The micellarization of lutein (25-40%) exceeded (p < 0.01) that of alpha- and beta-carotene (12-18%) and lycopene (<0.5%). Micellarization of carotenoids was not affected by elimination of the gastric phase of the digestive process. The absence of bile extract prevented the transfer of carotenoids from foods to micelles, whereas omission of pancreatin only reduced the micellarization of the carotenes. Differentiated cultures of Caco-2 human intestinal cells accumulated 28-46% of micellarized carotenoids from the medium after 6 h. These results support the usefulness of the in vitro digestion process as a rapid and cost-effective model for screening the bioavailability of carotenoids from meals.
TL;DR: Antioxidative mechanisms including metal ion chelating ability, scavenge of reactive oxygen species, enzyme inhibition, and reducing activity of intracellular cell-free extract of lactic acid bacteria were studied.
Abstract: Nineteen strains of lactic acid bacteria were investigated for antioxidative activity. These includedLactobacillus acidophilus B, E, N1, 4356, LA-1, and Farr; Lactobacillus bulgaricus 12 278, 448, 449, Lb, 1006, and 11 842; Streptococcus thermophilus 821, MC, 573, 3641, and 19 987; and Bifidobacterium longum B6 and 15 708. Intracellular cell-free extract of all strains demonstrated antioxidative activity with inhibition rates of ascorbate autoxidation in the range of 7-12%. Antioxidative mechanisms including metal ion chelating ability, scavenge of reactive oxygen species, enzyme inhibition, and reducing activity of intracellular cell-free extract of lactic acid bacteria were studied. S. thermophilus 821 had the highest metal ion chelating ability for Fe(2+), and B. longum 15 708 showed the highest Cu(2+) chelating ability among the 19 strains tested. All strains demonstrated reactive oxygen species scavenging ability. L. acidophilus E showed the highest hydroxyl radical scavenging ability, and B. longum B6 had the best hydrogen peroxide scavenging ability. Reducing activity was also found in all strains. Most of the strains tested demonstrated excellent reducing activity. B. longum B6 showed the highest reducing activity among the 19 strains tested. In enzyme inhibition, superoxide dismutase activity was not found in these 19 strains, and the activity of superoxide dismutase was not induced when metal ion Mn(2+), Fe(2+), or Cu(2+)Zn(2+) was present.
TL;DR: The procyanidin content of the samples was correlated to the antioxidant capacity measured using the ORAC assay as an indicator for potential biological activity and suggests the normal-phase high-performance liquid chromatography method is reliable and reproducible for quantification of procyansidins.
Abstract: Monomeric and oligomeric procyanidins present in cocoa liquors and chocolates were separated and quantified in four different laboratories using a normal-phase high-performance liquid chromatography (HPLC) method with fluorescence detection. Procyanidin standards through decamers were obtained by extraction from cocoa beans, enrichment by Sephadex LH-20 gel permeation chromatography, and final purification by preparative normal-phase HPLC. The purity of each oligomeric fraction was assessed using HPLC coupled to mass spectrometry. A composite standard was then prepared, and calibration curves were generated for each oligomeric class using a quadratic fit of area sum versus concentration. Results obtained by each of the laboratories were in close agreement, which suggests this method is reliable and reproducible for quantification of procyanidins. Furthermore, the procyanidin content of the samples was correlated to the antioxidant capacity measured using the ORAC assay as an indicator for potential biological activity.
TL;DR: This multidiscipline-oriented overview surveys the present knowledge of the chemistry, nutrition, safety, microbiology, and pharmacology of D-amino acids.
Abstract: Exposure of food proteins to certain processing conditions induces two major chemical changes: racemization of all l-amino acids to d-isomers and concurrent formation of cross-linked amino acids such as lysinoalanine. Racemization of l-amino acids residues to their d-isomers in food and other proteins is pH-, time-, and temperature-dependent. Although racemization rates of the 18 different l-amino acid residues in a protein vary, the relative rates in different proteins are similar. The diet contains both processing-induced and naturally formed d-amino acids. The latter include those found in microorganisms, plants, and marine invertebrates. Racemization impairs digestibility and nutritional quality. The nutritional utilization of different d-amino acids varies widely in animals and humans. In addition, some d-amino acids may be both beneficial and deleterious. Thus, although d-phenylalanine in an all-amino-acid diet is utilized as a nutritional source of l-phenylalanine, high concentrations of d-tyrosin...
TL;DR: The findings indicate the following: the antioxidant efficiency of orange juices may be attributed, in a significant part at least, to their content of total phenols, while ascorbic acid seems to play a minor role.
Abstract: Several fresh orange juices, obtained from five different Citrus sinensis (L.) Osbeck varieties (three pigmented varieties, Moro, Sanguinello, and Tarocco, and two blond varieties, Valencia late and Washington navel), were subjected to antioxidant profile determination (including total polyphenols, flavanones, anthocyanins, hydroxycinnamic acids, and ascorbic acid). The antioxidant activity of these juices was then assessed by means of different “in vitro” tests (bleaching of the stable 1,1-diphenyl-2-picrylhydrazyl radical; peroxidation, induced by the water-soluble radical initiator 2,2‘-azobis(2-amidinopropane) hydrochloride, on mixed dipalmitoylphosphatidylcholine/linoleic acid unilamellar vesicles; scavenging activity against nitric oxide; total antioxidant status). All orange juices tested showed an evident antioxidant effect. Our findings indicate the following: (1) the antioxidant efficiency of orange juices may be attributed, in a significant part at least, to their content of total phenols, (2)...
TL;DR: A decrease in the total antioxidant activity was observed during storage, particularly important in MAP-stored spinach, and could explain this antioxidant activity decrease.
Abstract: The effect of modified atmosphere packaging (MAP) and cooking on the flavonoids and vitamin C content (ascorbic + dehydroascorbic acid; AA + DHAA) of fresh-cut spinach was evaluated. The total flavonoid content (approximately 1000 mg kg(-)(1) f.w.) remained quite constant during storage in both air and MAP atmospheres, while vitamin C (750 mg kg(-)(1)f.w.) was better preserved in MAP-stored spinach. AA was transformed to DHAA during storage, and its concentration was higher in MAP-stored tissues. The free-radical scavenging activity of the isolated flavonoids was tested, and only those flavonoids with either a dihydroxyl grouping or acylated with ferulic acid showed significant activity. A decrease in the total antioxidant activity was observed during storage, particularly important in MAP-stored spinach. The higher content of DHAA and lower content of both AA and antioxidant flavonoids in the MAP-stored samples could explain this antioxidant activity decrease. Boiling extracted 50% of total flavonoids and 60% vitamin C in the cooking water. However, flavonoid glucuronides were extracted more in the cooking water than the other glycosides. The vitamin C content of the cooked tissue was higher in those samples stored in MAP.
TL;DR: This study has found that autumn or winter was the best harvest time to obtain oils with high thujone levels, and major seasonal changes were found in the composition of oil distilled from a flowering type of Dalmatian sage.
Abstract: The factors affecting oil yield and quality of essential oils from Dalmatian sage (Salvia officinalis L.) are analyzed. Distillations of oils from individual plants and GC analyses revealed the presence of three chemotypes with different proportions of α- and β-thujone (α/β 10:1, 1.5:1, and 1:10). Different accessions could also be classified as having high (39−44%), medium (22−28%), or low (9%) total thujone contents. Flowering parts of S. officinalis had higher oil contents (1.6 versus 1.1%) and β-pinene levels (27 versus 10%) than leaves and lower thujone levels (16 versus 31%). Major seasonal changes were found in the composition of oil distilled from a flowering type of Dalmatian sage, but oil yields from healthy, established plants did not vary greatly. Total thujone levels were lowest (25%) around flowering in spring and summer, so autumn or winter was the best harvest time to obtain oils with high thujone levels. Keywords: Dalmatian sage; Salvia officinalis; essential oil; variation; thujones
TL;DR: The result of amino acid analysis showed that RBPI had a similar profile of essential amino acid requirements for 2-5-year-old children in comparison to that of casein and soy protein isolate.
Abstract: Rice bran protein isolate (RBPI) containing approximately 92.0% protein was prepared from unstabilized and defatted rice bran using phytase and xylanase. The yield of RBPI increased from 34% to 74.6% through the use of the enzymatic treatment. Nitrogen solubilities of RBPI were 53, 8, 62, 78, 82, and 80% at pHs 2.0, 4.0, 6.0, 8.0, 10.0, and 12.0, respectively. Differential scanning calorimetry showed that RBPI had denaturation temperature of 83.4 degrees C with low endotherm (0.96 J/g of protein). RBPI had similar foaming properties in comparison to egg white. But emulsifying properties of RBPI were significantly lower than those of bovine serum albumin. The result of amino acid analysis showed that RBPI had a similar profile of essential amino acid requirements for 2-5-year-old children in comparison to that of casein and soy protein isolate.
TL;DR: The results indicated that anthocyanins are incorporated keeping structurally intact glycoside forms, from the digestive tract into the blood circulation system in mammals.
Abstract: We determined red fruit anthocyanins, cyanidin-3-glucoside (Cy-g) and cyanidin-3,5-diglucoside (Cy-dg), incorporated into plasma and liver of rats and human plasma by UV-HPLC. Fifteen minutes after an oral supplementation of a mixture of 320 mg of Cy-g and 40 mg of Cy-dg/kg of body weight, rats showed an increase to a maximum of 1563 μg (3490 nmol) of Cy-g/L and 195 μg (320 nmol) of Cy-dg/L in plasma and 0.067 μg (0.15 nmol) of Cy-g/g and a trace of Cy-dg together with methylated metabolites such as peonidin-3-glucoside in liver. In human plasma, 30 min after intake (2.7 mg of Cy-g and 0.25 mg of Cy-dg/kg of body weight), an average of 11 μg (24 nmol) of Cy-g/L and a trace of Cy-dg were found. Cyanidin as aglycone of Cy-g and Cy-dg was not found in such plasma samples, neither were conjugated and methylated anthocyanins. The results indicated that anthocyanins are incorporated keeping structurally intact glycoside forms, from the digestive tract into the blood circulation system in mammals. Keywords: Anth...
TL;DR: A diet rich in these radical scavengers would reduce the cancer-promoting action of ROO(*).
Abstract: We recently reported that alkylperoxyl radical (ROO•) enhanced carcinogenesis in rats treated with carcinogen (Sawa et al. Cancer Epidemiol. Biomarkers Prev. 1998, 7, 1007−1012), and the tumor promoting action of ROO• could be reduced by addition of hot-water extracts of vegetables (Maeda et al. Jpn. J. Cancer Res. 1992, 83, 923−928). Here we described the ROO•-scavenging activity of flavonoids and nonflavonoid phenolics and their role in anti-tumor-promoter effects. A model molecular species, ROO•, was generated from tert-butyl hydroperoxide (t-BuOOH) and heme iron, and the scavenging of t-BuOO• was determined by (a) bioassay based on the bactericidal action of ROO•, (b) luminol-enhanced chemiluminescence, and (c) electron spin resonance. Of 17 authentic plant phenolics tested, 9 compounds (including rutin, chlorogenic acid, vanillin, vanillic acid, neohesperidin, gallic acid, shikimic acid, rhamnetin, and kaempferol) showed remarkably high ROO•-scavenging activity. Some of them were detected and quantif...
TL;DR: Phenolic and orthodiphenolic compounds together with carotenoids, tocopherols, pigments, and fatty acids were tested for their antioxidant effect in 79 samples of virgin olive oils cv.
Abstract: Phenolic and orthodiphenolic compounds together with carotenoids, tocopherols, pigments, and fatty acids were tested for their antioxidant effect in 79 samples of virgin olive oils cv. Picual and Hojiblanca. A linear regression based on the oleic/linoleic ratio and the contents of phenols and tocopherols showed a good correlation (adjusted-R(2) = 0.91) with the stability measured by Rancimat, later verified with an external text set (adjusted-R(2) = 0.95). A tentative study on the percentage contribution of each chemical variable to stability is discussed. The contribution of phenolic and orthodiphenolic compounds was around 51%, the composition of fatty acids 24%, and in less percentage alpha-tocopherol, carotenoids, and chlorophylls. No effect, or very little, was shown by beta- and gamma-tocopherols.
TL;DR: Higher levels of lipid oxidation products were found in the aroma extracts of all of the steaks with increased PUFA content, after cooking, and these compounds were derived from the autoxidation of the more abundant mono- and di-unsaturated fatty acids during cooking.
Abstract: The effect of n-3 polyunsaturated fatty acids (PUFAs) in beef muscle on the composition of the aroma volatiles produced during cooking was measured. The meat was obtained from groups of steers fed different supplementary fats: (i) a palm-oil-based control; (ii) bruised whole linseed, which increased muscle levels of alpha-linolenic (C18:3 n-3) and eicosapentaenoic acid (EPA, C20:5 n-3); (iii) fish oil, which increased EPA and docosahexaenoic acid (C22:6 n-3); (iv) equal quantities of linseed and fish oil. Higher levels of lipid oxidation products were found in the aroma extracts of all of the steaks with increased PUFA content, after cooking. In particular, n-alkanals, 2-alkenals, 1-alkanols, and alkylfurans were increased up to 4-fold. Most of these compounds were derived from the autoxidation of the more abundant mono- and di-unsaturated fatty acids during cooking, and such autoxidation appeared to be promoted by increased levels of PUFAs.
TL;DR: High-purity gamma-oryzanol was obtained from crude rice bran oil using a normal-phase preparative scale HPLC and identification was accomplished using GC/MS with an electron impact mass spectrum after components were transformed into trimethylsilyl ether derivatives.
Abstract: High-purity gamma-oryzanol was obtained from crude rice bran oil using a normal-phase preparative scale HPLC. A reverse-phase HPLC method was used for separating the individual components of gamma-oryzanol present in rice bran oil. Ten fractions were isolated and collected using the reverse-phase HPLC method, and their structures were identified. Identification was accomplished using GC/MS with an electron impact mass spectrum after components were transformed into trimethylsilyl ether derivatives. The 10 components of gamma-oryzanol were identified as Delta(7)-stigmastenyl ferulate, stigmasteryl ferulate, cycloartenyl ferulate, 24-methylenecycloartanyl ferulate, Delta(7)-campestenyl ferulate, campesteryl ferulate, Delta(7)-sitostenyl ferulate, sitosteryl ferulate, compestanyl ferulate, and sitostanyl ferulate. Three of these, cycloartenyl ferulate, 24-methylenecycloartanyl ferulate, and campesteryl ferulate, were major components of gamma-oryzanol.
TL;DR: Phenolic compounds in Spanish virgin olive oils were characterized by HPLC and the structure of a new compound was elucidated by MS and NMR as being that of 4-(acetoxyethyl)-1,2-dihydroxybenzene, which increased their concentration in oils with maturation of fruits.
Abstract: Phenolic compounds in Spanish virgin olive oils were characterized by HPLC. Simple phenols such as hydroxytyrosol, tyrosol, vanillic acid, p-coumaric acid, ferulic acid, and vanillin were found in most of the oils. The flavonoids apigenin and luteolin were also found in most of the oils. The dialdehydic form of elenolic acid linked to tyrosol and hydroxytyrosol was also detected, as were oleuropein and ligstroside aglycons. The structure of a new compound was elucidated by MS and NMR as being that of 4-(acetoxyethyl)-1,2-dihydroxybenzene. Changes of phenolic compounds in virgin olive oils with maturation of fruits were also studied. Hydroxytyrosol, tyrosol, and luteolin increased their concentration in oils with maturation of fruits. On the contrary, glucoside aglycons diminished their concentration with maturation. No clear tendency was observed for the rest of the phenolic compounds identified.
TL;DR: The observed genetic variability of carotenoids in fresh market sweet corn suggests profound differences in potential health promotion among genotypes and supports the feasibility of developing germplasm with enhanced levels of these antioxidant compounds at dosages that could promote health among the consuming public.
Abstract: Recent investigations into carotenoid and tocopherol biological activity in mammalian systems indicate that these antioxidants are associated with the prevention of degenerative diseases. Both carotenoids and tocopherols can be found in corn kernel tissue. A replicated survey of 44 sweet and dent corn lines was conducted to determine qualitative and quantitative variability of lutein, zeaxanthin, β-cryptoxanthin, α-carotene, and β-carotene, as well as the α-, δ-, and γ- forms of tocopherol. The primary carotenoids in fresh market sweet corn were found to be lutein and zeaxanthin, with the γ form dominating among the tocopherols. Mean values among the genotypes were observed to range from 0 to 20.0 and 2.4 to 63.3 μg/g dry weight for lutein and γ-tocopherol, respectively, indicating variability among genotypes in genes regulating the metabolism of these compounds. The observed genetic variability suggests profound differences in potential health promotion among genotypes and supports the feasibility of dev...
TL;DR: A national sampling plan was developed to select the most widely used isoflavone-containing foods in the United States and Isoflavones were analyzed from composite samples, raw and cooked, and reported by brand.
Abstract: A national sampling plan was developed to select the most widely used isoflavone-containing foods in the United States. Foods were selected based on their retail volume and sampled in five geographical areas representing seven metropolitan areas. Isoflavones were analyzed from composite samples, raw and cooked, and reported by brand. Quality control measures were evaluated throughout the study. Isoflavone levels ranged from 1 μg/g in soy sauces to 540 μg/g in tempeh. Soymilk and tofu represented the major portion of soy foods evaluated. These data will appear in the electronic version of USDA Handbook No. 8 of Food Composition Data in 1999. Keywords: Phytoestrogens; genistein; glycitein; daidzein; biochanin A; formononetin
TL;DR: Principal component analysis revealed that the distributions of Citrus species belonging to different classes were largely in accordance with Tanaka's classification system.
Abstract: Twenty-four flavonoids have been determined in 66 Citrus species and near-citrus relatives, grown in the same field and year, by means of reversed phase high-performance liquid chromatography analysis. Statistical methods have been applied to find relations among the species. The F ratios of 21 flavonoids obtained by applying ANOVA analysis are significant, indicating that a classification of the species using these variables is reasonable to pursue. Principal component analysis revealed that the distributions of Citrus species belonging to different classes were largely in accordance with Tanaka's classification system.
TL;DR: The protein/polyphenol ratio has a strong influence on the amount of haze formed; the largest amount occurs when the numbers of polyphenol binding ends and protein binding sites are nearly equal.
Abstract: The haze-forming activity of a polypeptide depends greatly on its proline content. Haze-forming polyphenols have at least two binding groups, each of which has at least two hydroxy groups on an aromatic ring. The protein/polyphenol ratio has a strong influence on the amount of haze formed; the largest amount occurs when the numbers of polyphenol binding ends and protein binding sites are nearly equal. This has important consequences for turbidimetric methods used to measure haze-active proteins and polyphenols in beverages. The ratio also influences the effectiveness of a number of stabilization procedures.
TL;DR: There is a potential for oat products, especially those enriched in outer layers of the groat, to contribute to dietary intakes of antioxidant phytonutrients, and regression equations that predicted antioxidant activity from phenolic and tocol concentrations were calculated.
Abstract: Oat milling fractions were examined for concentrations of total phenolics, tocols, and phenolic acids and in vitro antioxidant activity to determine their potential as dietary antioxidants. Methanolic extracts of pearling fractions, flour and aspirations from flaking, and trichomes had high, intermediate, and low antioxidant activities, respectively, evaluated by the beta-carotene bleaching method. Pearling fractions were also highest in total phenolics and tocols. p-Hydroxybenzoic acid, vanillic acid, caffeic acid, vanillin, p-coumaric acid, and ferulic acid were identified and quantified by HPLC. Three avenanthramides and an unidentified ferulate derivative were also detected. Total phenolic content was significantly correlated with antioxidant activity, and regression equations that predicted antioxidant activity from phenolic and tocol concentrations were calculated. Antioxidant activity, evaluated by beta-carotene bleaching, was correlated with measures of oxygen radical absorbance capacity and low-density lipoprotein oxidation. These data indicate a potential for oat products, especially those enriched in outer layers of the groat, to contribute to dietary intakes of antioxidant phytonutrients.
TL;DR: The cortex of 14 French apple varieties, one English cider variety, and one dessert apple were studied for their polyphenol composition, and procyanidins were always the predominant class.
Abstract: The cortex of 14 French apple varieties (12 cider and 2 juice varieties), one English cider variety, and one dessert apple (i.e., Golden Delicious) were studied for their polyphenol composition. Total polyphenols were assayed by the Folin-Ciocalteu method, and the precise polyphenolic composition (monomeric catechins, proanthocyanidins, hydroxycinnamic acids, and dihydrochalcones) was obtained by HPLC following thiolysis. ESI-MS and ESI-MS/MS analyses showed that chlorogenic acid and p-coumaroylquinic acid were methylated under the conditions of thiolysis. Depending on the variety, the global polyphenol concentration varied from 1 to 7 g per kilogram of fresh cortex. Cider varieties globally showed a higher polyphenol concentration than the dessert apple Golden Delicious, bitter varieties being the more concentrated. The proportion of the polyphenol classes varied greatly from one cultivar to another. For all varieties, procyanidins were always the predominant class. They were mainly constituted of (-)-epicatechin units with a small proportion of (+)-catechin as a terminal unit. The average degree of polymerization ranged between 4.2 and 7.5 depending upon the variety with an exception for the sharp varieties Guillevic and Avrolles which showed significant concentrations of procyanidins with DPn of 40 and 50, respectively.