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1.
This study identified the role of milling and parboiling on arsenic (As) content and its species in large numbers of rice samples. Total As contents were 108 ± 33 μg/kg in polished rice grains (PR), 159 ± 46 μg/kg in unpolished rice grains (UR), 145 ± 42 μg/kg in parboiled polished rice grains (PPR) and 145 ± 44 μg/kg in parboiled unpolished rice grains (PUR). The percentages of inorganic As (iAs) were 66% ± 8% in PR and from 72% to 77% in other grain categories. The polishing process reduced the As content in the rice grains, removing outer part of the UR with high amount of As, whereas the parboiling technique transferred the semimetal content within the grain. Total As and iAs contents were not significantly different in UR, PPR and PUR, homogenizing its distribution inside the grains. The results allowed to understand how different operations affect As fate and its chemical forms in grains.  相似文献   

2.
The effects of different pretreatments on phytate and mineral contents were investigated in whole grain barley and oat tempe fermented with Rhizopus oligosporus. Different varieties of barley and oats were exposed to pretreatments such as pearling, rolling, moistening, autoclaving and soaking before fermentation. Pearling was the most effective pretreatment for reduction of phytate content for both oats and barley. Nevertheless, mineral contents were reduced, and most likely cell wall rich fractions were also reduced by this process. In the first experiments the phytate content reduction in the oats and barley samples were reduced by 74% (3.3 μmol/g, d.m.) and 89% (1.4 μmol/g, d.m.), respectively. However, to improve iron absorption the phytate levels should not exceed 0.5 μmol/g, and further phytate degradation was necessary. Therefore, in the final experiments barley samples were exposed to an optimised process with prolonged soaking at a higher temperature and the pearling residues were returned before fermentation. When the outer layers of the barley kernels were returned before fermentation the phytate content was successfully reduced by 97% to 0.4 μmol/g (d.m.) and Fe and Zn levels were well preserved.  相似文献   

3.
The lipid profile of nuts from Ximenia caffra and Ricinodendron rautanenii was determined and compared. Although the total oil content of X. caffra and R. rautanenii nuts was similar (47.6 ± 7.5% versus 53.3 ± 13.7%), the fatty acid profiles differed significantly. X. caffra had a higher content (p < 0.05) of saturated fatty acids than R. rautanenii (20.19 ± 1.07% versus 13.87 ± 3.68%) and contained C22:0 and C24:0 which were lacking in R. rautanenii. Total monounsaturated fatty acids were higher in X. caffra than R. rautanenii (71.48 ± 0.99% versus 36.66 ± 1.95%). Oleic acid (C18:1n9) was the major monounsaturated fatty acid (MUFA) in X. caffra whereas erucic acid (C22:1n9), the major MUFA in R. rautanenii, was undetectable in X. caffra. R. rautanenii had a greater polyunsaturated fatty acid content than X. caffra which contained C18:3n3 (α-linolenic acid) and nervonic acid (24:1n9). X. caffra is potentially an important source of essential fatty acids.  相似文献   

4.
The color (L*, a*, b* parameters), the total phenols content and the global chemical composition (moisture, protein, fat, carbohydrates and ash) of four fresh varieties of olive leaves (Chemlali, Chemchali, Zarrazi and Chetoui) were determined. Fresh olive leaves are characterized by a green color (greenness parameter, a*, varying from ?5.01 ± 0.26 to ?9.14 ± 1.21), an intermediate moisture content (0.85 to 1.00 g/g dry matter, i.e. 46 to 50 g/100 g fresh matter) and a variable amount of total phenols according to the olive leaf variety (from ≈2.32 to ≈1.40 g caffeic acid/100 g dry matter).Fresh leaves were submitted to blanching and/or infrared drying at 40, 50, 60 and 70 °C in order to be stabilized by reducing their moisture contents. The impact of IR drying temperature on some quality attributes (color, total phenols and moisture rate removal) was evaluated. Nevertheless, the effect of prior blanching treatment on the quality attributes of dried leaves is less significant and it depends on the olive leaf variety. The infrared drying induces a considerable moisture removal from the fresh leaves (more than 85%) and short drying durations (varying from ≈162 at 40 °C to 15 min at 70 °C). IR drying temperature showed a significant effect of on total phenols content and the color of the leaves whatever the leaf variety. In fact, total phenols content of dried olive leaves increased if compared to fresh ones. For example, total phenols of Chemlali leaves increased from 1.38 ± 0.02 (fresh leaves) to 2.13 ± 0.29 (dried at 40 °C) and to 5.14 ± 0.60 g caffeic acid/100 g dry matter (dried at 70 °C). IR drying allows preserving the greenness color of fresh leaves and enhancing their luminosity. It could be suggested for preserving olives leaves before their use in food or cosmetic applications.  相似文献   

5.
In this paper, we describe a simple, fast, and efficient method for the quantification of simmondsins and simmondsin's ferulates in jojoba seeds and residual cakes, without using expensive equipment or laborious techniques. Spectrophotometric measurements (UV–vis) were used for the quantification of the content of simmondsins, total ferulates and total simmondsins in jojoba seeds and residual cakes from the provinces of Catamarca and La Rioja, Argentina. The average values of such components found in seeds, in 100 g of dry and defatted sample, were 11.54 ± 0.91 and 2.24 ± 0.28 g of simmondsins and of simmondsin's ferulates, respectively, whereas the respective values in residual cakes were 10.08 ± 0.31 and 2.93 ± 0.64 g, respectively. A great diversity between the simmondsin contents and their ferulates in seed samples of different origins as well as in different clones was observed. The residual cakes did not present differences respect to the simmondsin contents; however, there were some difference with the simmondsin ferulates. These variations are due to the genetic antecedents of plants and the environmental conditions in which they grow.  相似文献   

6.
The impact of the oxidants potassium bromate and potassium iodate and the reducing agent dithiothreitol (DTT) on the rheological behaviour of 20% (w/v) gluten-in-water suspensions during thermal treatment was monitored with the rapid visco analyser (RVA). The suspensions were subjected to a linear temperature increase from 40 to 95 °C in 14 min, a holding step of 40 min at 95 °C, a cooling step (7 min) with a linear temperature decrease to 50 °C, and a final holding step at 50 °C (13 min). Potassium iodate (1.18 and 1.77 μmol/g protein) and potassium bromate (1.52 and 15.2 μmol/g protein) decreased RVA viscosities in the holding step and increased sodium dodecyl sulphate (SDS) protein extractabilities suggesting a greater heat resistance and decreased gliadin–glutenin cross-linking. In contrast, in the presence of DTT (1.65 and 3.30 μmol/g protein) RVA viscosity increased at lower temperatures and lowered SDS extractabilities. It is postulated that low concentrations of reducing agent facilitate gliadin–glutenin cross-linking during heating while oxidants hinder gluten polymerization due to decreased levels of free sulphydryl groups and less flexibility of the glutenin chains.  相似文献   

7.
Changes in fatty acids were studied during maturation of coriander (Coriandrum sativum L.) fruits cultivated in the North-East of Tunisia (Charfine). The fruits matured in 55 days after flowering (DAF). Oil and petroselinic acid synthesis proceeded at a steady rate up to 32 DAF. The first results showed a rapid oil accumulation started at newly formed fruits (9.6 ± 0.2%) and continued until their full maturity (26.4 ± 0.5%). During fruit maturation, fatty acid profiles varied significantly among the nine stages of maturity. At the 32th DAF, palmitoleic, gadoleic, erucic and docosahexenoic acids were not detected and petroselinic acid had a highest amount (84.8 ± 4.5%). Fruits development resulted mainly in an increase of petroselinic acid and a decrease of palmitic acid (C16:0). At full maturity, the main fatty acids were petroselinic acid (80.9 ± 5.7%), followed by linoleic (13.6 ± 2.9%), palmitic (3.6 ± 0.1%) and stearic (0.7 ± 0.1%) acids. Saturated and polyunsaturated fatty acids decreased significantly and monounsaturated fatty acids increased during maturation of coriander fruit. Coriander fruits at the first four stages of maturity have a healthy nutritional value and the last five stages were with important economic and industrial applications. Results of this study indicate that the variation in the fatty acid composition of coriander fruit during maturation may be useful in understanding the source of nutritionally and industrially important fatty acids in this fruit. Coriander fruit is potentially an important source of petroselinic acid which has numerous industrial applications.  相似文献   

8.
In this work, the forward extraction of defatted wheat germ protein (DWGP) by reverse micelles was studied. The reverse micellar systems were formed by sulphosuccinic acid bis (2-ethylhexyl) ester sodium salt (AOT), isooctane and KCl solution. The effects of AOT concentration, pH, KCl concentration, extraction time, the amounts of defatted wheat germ flour (DWGF), W0 (the molar ratio of water to surfactant, i.e. W0 = [H2O]/[AOT]) and temperature on the forward extraction efficiency of DWGP were tested. On the basis of single-factor experiments, the optimum extraction was achieved by response surface methodology (RSM). The experimental results lead to the conclusion that the highest forward extraction efficiency of DWGP was reached at the AOT concentration 0.06 g/mL, pH 8, KCl concentration 0.1 mol/L, time 30 min, the amounts of DWGF 0.500 g, W0 25 and temperature 36 °C. Under these conditions, the forward extraction efficiency of DWGP achieved 37%.  相似文献   

9.
Applications of ultrahigh CO2 treatments accelerated cuphea (Cuphea viscosissima × C. lanceolata ‘PSR23’) growth and development and aided in seedling establishment. The growth (fresh weight) and morphogenesis (number of leaves and roots and seedling length) were determined in cuphea seedlings exposed to 350, 1500, 3000, 10,000, or 30,000 μmol mol−1 CO2 for 30 days under greenhouse conditions. Greater CO2 levels, especially the ultrahigh levels (i.e. ≥3000 μmol mol−1 CO2) resulted in significantly higher (P  0.05) fresh weights, leaf numbers, root numbers, and seedling lengths compared to seedlings grown under ambient air (350 μmol mol−1 CO2). For example, cuphea ‘PSR23’ Morris heavy seedlings showed the greatest seedling fresh weight, leaf number, root number, and seedling length when supplemented with 10,000 μmol mol−1 CO2 increasing 607%, 184%, 784%, and 175%, respectively, when compared to seedlings grown without CO2 enrichment.  相似文献   

10.
Thymus zygis ssp. gracilis shrubs were cultivated as an experimental crop under different watering level, in order to achieve 81, 63, 44 and 30% of the local potential evapotranspiration (ETo). After 4 years of cultivation, thyme leaves were analyzed on the basis of their essential oil (yield and quality), total phenolic content, free radical-scavenging activity and polyphenolic profile.Essential oil yield values ranged between (2.3 ± 0.7) and (3.6 ± 0.7)% for 81 and 30% ETo equivalent, respectively. The comparison of essential oil production at the 2nd and 4th years of cultivation showed that using watering levels higher than 30% ETo equivalents reduced significantly (P < 0.05) the essential oil yielded by these shrubs with time.Analysis of total phenolic content, polyphenolic profile, and radical scavenging activity were performed using post-distillation dry leaves. Total phenolic content values ranged from (122.2 ± 19.3) to (108.5 ± 19.2) mg of gallic acid equivalents (GAEs)/g of dry plant for the highest and lowest watering level treatment, respectively. Regarding the polyphenolic profile, rosmarinic acid, followed by apigenin, ferulic, carnosic and caffeic acids, was the phenolic component quantified at the highest concentrations. Radical-scavenging activities (IC50) concentrations varied from (3.7 ± 1.6) mg/mL for 81% ETo to (7.4 ± 2.3) mg/mL 30% ETo.In spite of the intra-specific variability detected, the individual analysis of shrubs has allowed the selection of plants which are characterised by having adequate levels of essential oil and polyphenolic extract (yield and quality), almost all of them being cultivated under a 60% ETo watering level. These selected shrubs will allow us to make further vegetative propagations in order to obtain homogeneous field crops with plants of contrasted quality cultivated under a 60% ETo watering level.  相似文献   

11.
The influence of guar and xanthan gum and their combined use on dough proofing rate and its calorimetric properties was investigated. Fusion enthalpy, which is related to the amount of frozen water, was influenced by frozen dough formulation and storage time; specifically gum addition reduced the fusion enthalpy in comparison to control formulation, 76.9 J/g for formulation with both gums and 81.2 J/g for control, at 28th day. Other calorimetric parameters, such as Tg and freezable water amount, were also influenced by frozen storage time. For all formulations, proofing rate of dough after freezing, frozen storage time and thawing, decreased in comparison to non-frozen dough, indicating that the freezing process itself was more detrimental to the proofing rate than storage time. For all formulations, the mean value of proofing rate was 2.97 ± 0.24 cm3 min−1 per 100 g of non-frozen dough and 2.22 ± 0.12 cm3 min1 per 100 g of frozen dough. Also the proofing rate of non-frozen dough with xanthan gum decreased significantly in relation to dough without gums and dough with only guar gum. Optical microscopy analyses showed that the gas cell production after frozen storage period was reduced, which is in agreement with the proofing rate results.  相似文献   

12.
The leaf pulp of Aloe vera, designated as the gel, and the bitter, yellow liquid fraction have been tested against pathogens (bacteria and fungi) affecting human and plants. However, their activity for fungal control in commercial industrial crops has not been determined. The objectives of this study were to evaluate the inhibitory effect of Aloe pulp and liquid fraction on the mycelial growth of three phytopathogenic fungi and to determine the extract concentrations that can inhibit mycelial development. A. vera leaves were cut from plants grown under greenhouse conditions at the University Antonio Narro, disinfected with sodium hypochlorite, and separated in two groups. In the first group, the pulp was manually scraped out; in the second, a laboratory roll processor was used for the pulp and liquid fraction separation. Both types of extracts were pasteurized. Antifungal activity of pulp and liquid fraction was evaluated on the mycellium development of Rhizoctonia solani, Fusarium oxysporum, and Colletotrichum coccodes that were isolated from a potato crop by the hyphae point and monosporic techniques. The concentrations of the plant extract ranged from 0 to 105 μl l−1. Fungal plugs 0.4 mm in diameter were placed in Petri dishes with a potato–dextrose–agar (PDA) culture media, and treated with various concentrations of pulp or liquid fraction. The cultures were incubated at 24±2 °C and the radial growth of mycelia measured daily for 7 days. The antifungal effect was measured under a totally random design with four replications. The results showed an inhibitory effect of the pulp of A. Vera on F. oxysporum at 104 μl l−1 and over a long period. For the two types of Aloe fractions the activities were similar. Besides the liquid fraction reduced the rate of colony growth at a concentration of 105 μl 1−1 in R. solani, F. oxysporum, and C. coccodes. This is the first report of any Aloe liquid fraction activity against plant pathogenic fungi.  相似文献   

13.
Structure and health effects of inulin-type fructans have been extensively studied, while less is known about the properties of the graminan-type fructans in wheat. Arabinoxylan (AX) is another important indigestible component in cereal grains, which may have beneficial health effects. In this study, the fructan content in milling fractions of two wheat cultivars was determined and related to ash, dietary fibre and AX contents. The molecular weight distribution of the fructans was analysed with HPAEC-PAD and MALDI-TOF MS using 1H NMR and enzymatic hydrolysis for identification of fructans. The fructan content (g/100 g) ranged from 1.5 ± 0.2 in flour to 3.6 ± 0.5 in shorts and 3.7 ± 0.3 in bran. A correlation was found between fructan content and dietary fibre content (r = 0.93, P < 0.001), but with a smaller variation in fructan content between inner and outer parts of the grain. About 50% of the dietary fibre consisted of AX in all fractions. The fructans were found to have a DP of up to 19 with a similar molecular weight distribution in the different fractions.  相似文献   

14.
Evening primrose (Oenothera biennis) is increasingly cultivated for medicinal use of the γ-linolenic acid rich oil. The seed cake (EPSC) – the remaining industrial residue from cold pressing – was extracted with polar solvents in order to investigate a profitable polyphenolic recovery. The extractable matter and the total phenolic content (Folin-Ciocalteu) have been compared to a black currant residue from juice production (Ribes nigrum) and seed cakes from sesame, woad (Isatis tinctoria) and burdock (Arctium lappa). The EPSC crude extracts yielded the high total phenolic content (min 228.2 ± 11.6 to max 696.4 ± 29.0 mg GAE g−1 dry extract) within the range of already commercialized antioxidant extracts from rosemary (RO, 142.1 ± 1.9 mg g−1), green tea (GT, 446.8 ± 27.4 mg g−1) and grape seed (GS 790.0 ± 53.1 mg g−1). All extracts exhibited free radical scavenging activity (DPPH assay) with the order of potency: EPSC > GS > GT  burdock = black currant > RO > butylated hydroxytoluene (BHT)  woad > sesame. Accordingly EPSC extracts where very effective in scavenging superoxide anion radicals (neotetrazolium assay: GS > EPSC > GT  BHT > burdock > woad > sesame) and inhibition of lipid oxidation (Rancimat assay: BHT  GT > EPSC  burdock > woad > RO > sesame > GS). Decreasing Rancimat activity from 80 °C upwards might indicate heat sensitiveness and limited usability. However, an efficient exploitation of polyphenols from evening primrose seed cakes in terms of an uncomplicated extraction procedure, the yield and the competitive profile as a strong radical scavenger can be concluded.  相似文献   

15.
There are 32 species of Flourensia genus with 9 native to Mexico. These species contain compounds with potential use for pest control. In this paper, we report the antifungal activities of ethanol extracts from three endemic species in Coahuila state: Flourensia microphylla, Flourensia cernua, and Flourensia retinophylla. Also, preliminary information on the chemical composition of the extracts is included. Antifungal activity was tested against three pathogens attacking commercial crops: Alternaria sp., Rhizoctonia solani, and Fusarium oxysporum. The extracts concentration varied from 10 to 1500 μl l−1. The ANOVA showed highly significant differences (P  0.01) with the extracts, the doses, and on the interaction extract × dose. Inhibition effect was observed from 10 μl l−1 in all three species. Total inhibition was found only with F. cernua and F. retinophylla at 1000 μl l−1 for R. solani, the three species inhibited the three pathogens at 1500 μl l−1. Infrared analysis showed similar absorption signals for the extracts of the three species although in different concentration. This suggests that similar compounds may be present. The control of these pathogens by natural compounds is interesting both for environmental and economic reasons. The use of semiarid lands plants may improve the socioeconomic level of the people within the region.  相似文献   

16.
Effect of pressing time on physical and mechanical properties of phenolic-impregnated bamboo strips was evaluated. Bamboo strips (Gigantochloa scortechinii) were impregnated with low molecular weight phenol formaldehyde (LMwPF) resin. Samples were submerged in LMwPF resin using a vacuum chamber of 750 mmHg for 1 h before it was released within 1.5 h. Treated strips were dried in an oven with a temperature of 60 °C within 6–9 h. It was hot pressed at 14 kg m?2 and a temperature of 140 °C for 5, 8, 11, 14 and 17 min. The physical and mechanical properties of the test indicated that the properties of phenolic-treated strips have significantly increased as compared to control samples. Dimensional stability (water absorption, thickness swelling and linear expansion) of the phenolic-treated properties were significantly lower than control after 5-min pressing time. The antishrink efficiency (ASE) of phenolic-treated strips increased when pressing time were extended from 5 to 17 min. The mean value of modulus of rupture (MOR) for the control samples (177 N mm?2) showed a significant difference with phenolic-treated strips after 17-min pressing time (224 N mm?2). However, there is no significant difference in compression parallel to grain. The MOE of phenolic-treated strips was 21,777 N mm?2 and for control was 18,249 N mm?2, whereas the compression parallel to grain values for phenolic-treated and control samples were 94 and at 77 N mm?2, respectively.  相似文献   

17.
Eight different oilseed crops (Brassica carinata, Camelina sativa, Coriandrum sativum, Euphorbia lagascae, Lepidium sativum, Lesquerella fendleri, Madia sativa, Vernonia galamensis) grown in Italy were investigated regarding anti-nutritive compounds, such as glucosinolates, sinapine, inositol phosphates and condensed tannins, which can adversely affect the nutritional value of residues from the oilseed processing. In all seeds at least one anti-nutritive compound was found, which possibly could lower the nutritive value, but in most cases a real negative effect is not to be expected. The existence and the concentration of the different anti-nutritive components varied in the different seeds. Glucosinolates and sinapine were found only in seeds of B. carinata, L. sativum, C. sativa and L. fendleri, whereas condensed tannins and inositol phosphates appeared in all seeds. In the different seeds the amount ranged from 0.2 mg/g (L. fendleri) to 13.1 mg/g (L. sativum) for sinapine, from 0.4 mg/g (E. lagascae) to 19.6 mg/g (L. fendleri) for condensed tannins, from 6.6 mg/g (E. lagascae) to 23.1 mg/g (B. carinata) for inositol hexa-phosphate as well as from 18.7 μmol/g (C. sativa) to 164.6 μmol/g (L. sativum) for glucosinolates.  相似文献   

18.
As part of a large programme [Scottish Executive Rural Affairs Department Programme of Agricultural, Biological and Related Research: Exploitation of Novel and Known Lectins in Agricultural and Biological Research—an Interdisciplinary Approach to Improve Crop Protection and Productivity, Animal (Including Human) Welfare and Health (Project No. FF821). Scottish Executive Rural Affairs Department (http://www.scotland.gov.uk/abrg/docs/pabr-00.asp)] concerned with the discovery and development of new and existing plant lectins, a screening exercise for novel mannose binding lectins (MBLs) was initiated. Common agricultural and horticultural crops were screened and of the 50 species initially screened, 15 were shown to be putative sources of MBLs. Following isolation by mannose-affinity and phenyl-Sepharose™ chromatographies the proteins were characterised with regard to their structure and functionality. The species within the Amaryllidacea and Liliaceae had the MBLs present at the greatest levels (≤6000 μg [g fresh wt.]−1). The novel MBLs were present at relatively low levels (15–60 μg [g fresh wt.]−1). All the MBLs exhibited monomer molecular weights in the range 11–13 kD whilst the native molecular weights were indicative of dimer or tetramer formation.The linkage preferences of the MBLs were determined by inhibiting the MBL-yeast mannan precipitation reaction by the addition of oligomannans with defined linkages. The preference for α(1–3) and α(1–6) linkages was predominant throughout the known and novel MBLs. Evidence of binding to α(1–2) and α(1–4) linked ligands was seen but the relative affinity for these was low with the exception of the MBL from leafbeet (Beta vulgaris ssp. cicla). The MBL from celeriac (Apium graveolens) did bind β-linked ligands but this was most probably due to a lack of specificity rather than a different specificity. Overall the relative binding affinity of the MBLs increased with increasing complexity of the ligands.  相似文献   

19.
20.
In the present work, thermogravimetric analysis of 17 organosolv lignin samples was carried out to determine their thermal stability and calculate the kinetic parameters of their pyrolysis. The thermal stability has been estimated by the measurement of the degradation temperature (Td), calculated according to the maximum reaction rate. In addition, degradation temperature at 10% of conversion (T10%) has been obtained in order to compare the initial stability of the samples with Td for all samples. The values of Td are comprised between 262 and 389 °C and the average value is 340 °C. The range for T10% is 251–320 °C and the average value is 270 °C. The ashes content of the samples has been analyzed and all the residues presented values lower than 4 wt%. Kinetic parameters of lignin pyrolysis were calculated by Borchardt–Daniels’ method assuming nth order reaction. The activation energy values obtained are comprised between 17.9 and 42.5 kJ/mol and the average value is 28.1 kJ/mol. These results are in agreement with the bibliography.  相似文献   

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