菠菜提取物抗氧化性研究

本文研究了菠菜的抗氧化性,采用不同极性溶剂对菠菜中的抗氧化性物质进行提取,测定不同极性提取物中的总酚、总黄酮含量及DPPH自由基清除率,发现95%乙醇本本效果最好本95%乙醇本本率为4.96%;本本含量为39.60μg/mg样品;本黄酮含量为17.53μg/mg样品;终浓度0.5mg/mL时本DPPH自由基本清除率为62.09%。     

Functional Properties of Canola Meals Produced by a Two-phase Solvent Extraction System

The functional properties of glucosinolate-free canola meals were studied and compared with those of hexane-extracted canola and soybean meals. The glucosinolate-free meals were obtained by a two-phase solvent extraction of canola seed using 10% NH₃ in methanol or in methanol containing 5% water, and hexane as the second phase. The glucosinolate content decreased to trace levels. The crude protein content in the meal was comparable to that of soybean meal. The two-phase solvent extraction process gave canola meals with lower solubility properties but with very high fat absorption compared to both the corresponding laboratory-prepared, hexane-extracted meals and commercially produced soybean meal.     

Fate of Singrin in Methanol/Ammonia/Water-Hexane Extraction of B. juncea Mustard Seed

The individual glucosinolates present in B. juncea mustard seed were determined. Sinigrin (allyl glucosinolate) was the major glucosinolate of mustard seed and constituted 92.9% of the total glucosinolates. The effect of CH₃OH/NH₃/H₂O-hexane treatment on the concentration of glucosinolates was studied. Over 97% of sinigrin originally present in the seed was removed by the above solvent extraction system, mainly in the intact form. Breakdown products of sinigrin were quantified in the treated meal, in the extracted oil and in the polar phase (gums). Aglycon products were allyl cyanide, allyl isothiocyanate and 2,3-epithiopropane cyanide. Sugar breakdown products were glucose, thioglucose, thioglucose dimer and furfuryl alcohol. Desulfosinigrin was a minor decomposition product and might have acted as an intermediate in the decomposition of sinigrin.     

Effect of Methanol-Ammonia-Water Treatment on the Concentration of Individual Glucosinolates of Canola

The effect of methanol-ammonia-water/hexane extraction of canola seed on the content of individual glucosinolates of their resulting meals was investigated. The level of original glucosinolates retained in the treated meals varied between 6% to 15% as determined by gas chromatography and high performance liquid chromatography. These correspond to values of about 4% to 10% for the aliphatic glucosinolates found in seeds routinely analyzed for canola designation. The concentration of these aliphatic, nonindole, glucosinolates in the treated meals was less than 1.8 μmol per gram while their total concentration did not exceed 4.3 μmol per gram of meal.     

Improving the phytochemical composition of broccoli sprouts by elicitation

In order to increase the concentrations of bioactive compounds in broccoli sprouts, exogenous elicitors: methionine, tryptophan, chitosan, salicylic acid (SA) and methyl jasmonate (MeJA) were sprayed at different concentrations during germination. The effects of the elicitors on vitamin C, phenolic compounds and glucosinolate levels were assessed in 3, 5 and 7-days old seedlings. The application of 200, 300 μM SA and 0.01% chitosan induced increases, by 26%, 18% and 54%, respectively in the content of vitamin C in 5 days old broccoli sprouts. Flavonoid concentration was also increased by 31% and 33% after 10 μM MeJA and 100 μM SA treatments, respectively in 7 days old broccoli sprouts. In contrast, methionine or tryptophan solutions did not positively affect the vitamin C or the phenolic compounds in the sprouts. The individual classes of glucosinolates respond differently to the elicitor treatment. Methionine, a sulphur-containing amino acid, applied at 5 mM, significantly increased, by 32%, the levels of aliphatic glucosinolates. However, indole glucosinolates presented a significant response to the induction with tryptophan, SA or MeJA treatments. Tryptophan at 10 mM concentration augmented by 1.8-fold the indole glucosinolate concentration in 7 days old broccoli sprouts, and the treatments of 100 μM SA and 25 μM MeJA also induced significantly higher amounts of indole glucosinolates (by 33% and 51%, respectively) in 7 days old treated broccoli sprouts. Therefore, the application of elicitors could be a useful tool for improving the bioactive metabolites in broccoli sprouts for fresh consumption or functional ingredients for nutraceuticals foods.     

Influence of glucosinolates and high-molecular factors on the nutritional value of low-glucosinolate rapeseed meal

In order to ascertain the reason for the prominent growth-inhibiting effect of unheated low-glucosinolate rapeseed meal, the nutritional value of various fractions of the meal was evaluated in growth experiments using mice. A meal containing myrosinase activity was not growth-inhibiting after the low-molecular compounds had been removed by dialysis. A hydrolysis of glucosinolates to isothiocyanates and oxazolidinethiones would probably not explain the marked antinutritional properties of the low-molecular fraction. Heat treatment after autolysis did not improve the nutritional value of the meal. The harmful factors present in an autolysed meal could be extracted with methylene chloride. This extract contained nitriles, but no isothiocyanates or oxazolidinethiones. Thus, together with other information, the results suggest that the growth-inhibiting effect of unheated, low-glucosinolate rapeseed meal is mainly due to the presence of factors that direct the hydrolysis of glucosinolates towards nitrile production.     

Rapeseed meal-glucosinolates and their antinutritional effects Part 5. Animal reproduction

Although there is no clear evidence to fully describe the mechanism involved in glucosinolate-related effects on animal reproduction, lowered fertility in animals fed diets with rapeseed meal (RSM) inclusion is related to glucosinolate content in the diet. Negative effects can result both from multidirectional action of glucosinolates, malnutrition of mother due to the thyroid dysfunction, transfer of goitrogenic compounds to foetus and reduced transfer of nutritive compounds (e.g. iodine) through the placenta. The degree of reproduction impairment depends both on glucosinolate content and on the type of animal. Pregnant female rats are sensitive to the presence of glucosinolates, and the first symptoms of fertility impairment and lowering of offspring survival rate may occur at low glucosinolate levels, e.g. with diets containing low glucosinolate rapeseed meal (LG-RSM). In the case of swine, the limiting value above which sows fertility may be impaired is 4 μmol of total glucosinolates per g diet and 8 mmol of daily intake of these compounds. Opinions on the permitted RSM inclusion in diet for hens are very divergent. Some authors recommend limiting of the RSM inclusion to 10%, while others did not find any lowering of egg production in hens fed diets with two- or three-fold greater RSM inclusion rates. Most long-term experiments with heifers, cows and ewes indicate that ruminants tolerate the level of glucosinolate in LG-RSM although feeding this fodder as the only high-protein concentrate component may lead to impaired fertility.     

Influence of light on health‐promoting phytochemicals of broccoli sprouts

BACKGROUND: Broccoli (Brassicaceae) is a rich source of phytochemicals (glucosinolates and phenolic compounds) and micronutrients (vitamins and minerals). Germinated broccoli sprouts contain much higher levels (10–100 times) of aliphatic (glucoraphanin) and indolic glucosinolates than the inflorescences. This quality characteristic of broccoli sprouts plays an important role in human health and disease prevention. Although it is known that genetic and environmental factors can affect the composition of broccoli inflorescences, the influence of such factors on the seeds and sprouts has not been widely reported. Therefore the aim of this study was to determine the effect of light versus dark growth conditions on the phytochemical composition (vitamin C, phenolic compounds and glucosinolates) of broccoli sprouts. RESULTS: Broccoli sprouts grown in the light were found to have much higher concentrations of vitamin C (by 83%), glucosinolates (by 33%) and phenolic compounds (by 61%) than those grown in the dark. During a 7 day period there was a clear and analogous trend in both treatments, with a general reduction in concentrations over time. Among the different organs studied (seeds, cotyledons, stems and roots), the cotyledons contained the highest levels of bioactive compounds, while the roots contained the lowest. CONCLUSION: Light treatment of sprouting broccoli seeds increased their concentration of health‐promoting phytochemicals, mainly during the first 3–5 days of development. Therefore the younger broccoli sprouts are a better source of bioactive compounds for the consumer than the inflorescences. Copyright © 2008 Society of Chemical Industry     

Changes occurring in phenolic content,tocopherol composition and oxidative stability of Camelina sativa oil during storage

Changes occurring during storage in the content of polar phenolic compounds, the composition of tocopherols (T), the presence of primary and secondary oxidative products and titratable acidity in oil obtained from the seeds of Camelina sativa were studied. In fresh oil the content of polar phenolic compounds amounted to 128 mg/kg (expressed as chlorogenic acid), the content of α-T was (41 ± 8) mg/kg, of γ-T (710 ± 19) mg/kg and of δ-T (12 ± 3) mg/kg. β-T and tocotrienols were not detected. In oil stored at 50 °C the concentration of total tocopherols decreased to a value of (440 ± 13) mg/kg in 15 days. In that time the content of polar phenolic compounds in the oil stored at 50 °C was reduced to 72% of its initial value. The content of polar phenolic compounds in oil stored at 65 °C for 15 days was reduced to 21% of its initial value. The content of polar phenolic compounds in the C. sativa oil investigated decreased linearly with peroxide value and with p-anisidine value. The antioxidative activity of polar phenolic compounds extracted from camelina oil was also elucidated. Analysis revealed that the phenolic extract obtained from camelina oil added to a model lipid system for a certain time significantly retarded the process of autooxidation.     

Influence of glucosinolates and native enzymes on the nutritional value of low-glucosinolate rapeseed meal.

This study attempted to find out whether the low content of glucosinolates in the seed of the rapeseed cultivar Bronowski significantly affects the nutritional value of the seed meal. Glucosinolates were extracted from unheated meal with cold acetone, a process giving rise to only a slight inactivation of enzymes. Mice fed with a diet containing this meal as the protein source showed similar growth, feed intake and protein efficiency ratio to mice fed with heat-treated meal. When glucosinolates were added to the acetone-extracted meal, bringing them to about the same amount as before the acetone extraction, the growth response of the mice was as poor as that of mice fed with unheated, unextracted meal. Thus, even such low amounts of glucosinolates as found in Bronowski seed meal significantly affect the nutritional value of the diet as long as the appropriate enzymes are present. Besides myrosinase, other enzymes influencing the hydrolysis of glucosinolates appear to exist in the meal.     

Rapeseed meal-glucosinolates and their antinutritional effects. Part II. Flavour and palatability

This paper has reviewed the current literature relating to the effects of glucosinolates on the palatability of rapeseed meal. The available evidence indicates that diet palatability can be adversely affected by rapeseed meal inclusion and that this response is related to glucosinolate level. However the response is variable and depends also on the species of animal, age and growth state. Younger animals, particularly chicks, piglets and calves appear to be more severely affected and exhibit reduced intake and hence depressed performance with diets containing high levels of glucosinolates from high glucosinolate rapeseed meal. Palatability is substantially improved by the use of low glucosinolate rapeseed meal (LG-RSM) containing 10–30 μ/g and very low glucosinolate rapeseed meal (VLG-RSM) containing 1–5 μ/g glucosinolates. From the findings of this review, it can be concluded that LG-RSM and VLG-RSM can be included at levels up to 20% and 30% for calves and dairy cows respectively. Since piglets are particularly sensitive it is suggested that rapeseed is excluded from early starter diets but that low glucosinolate meals can be included at levels of 10% and 15% for grower and finisher pigs respectively. Growing poultry may be less sensitive to palatability problems associated with rapeseed meal but the use of high levels is constrained due to the lower energy and higher fibre contents of RSM compared with soybean meal.     

茉莉花茶中茶多酚的提取分离纯化及其抗氧化性能研究

本实验采用溶剂法浸提茉莉花茶中茶多酚,研究发现,相对最优的工艺条件为:温度70℃,乙醇溶液浓度60%,提取次数1次,提取时间60min。在此浸提工艺下提取到茶多酚粗提物后用石油醚、氯仿和乙酸乙酯萃取,得乙酸乙酯相过聚酰胺柱分离纯化,将得到的不同洗脱组分过高效液相色谱检测发现:30%乙醇洗脱组分含表儿茶素没食子酸酯(ECG)最高,60%乙醇洗脱组分中含有表没食子儿茶素没食子酸酯(EGCG),95%乙醇洗脱组分主要是儿茶素没食子酸酯(CG)。继而对不同组分进行抗氧化活性研究得出:60%洗脱组分对油脂的抗氧化活性最高;30%洗脱组分与60%洗脱组分对DPPH自由基50%清除率的浓度分别为0.1723mg/ml、0.1693mg/ml。     

Cancer chemopreventive effect of fractions from cranberry products

Cancer chemopreventive properties were evaluated in HPLC fractions of different polarity obtained from two cranberry juices and three extracts isolated from frozen cranberries and pomace containing anthocyanins, water-soluble and apolar phenolic compounds, respectively. Compounds with close polarities were collected in order to obtain between three and four fractions from each juice or extract. Cranberry fractions were screened for their ability to induce the phase II xenobiotic detoxification enzyme quinone reductase (QR). The results showed that there was no cytotoxicity against the cells used in the test. All samples stimulated the quinone reductase activity except the highest concentrations of the less polar fraction of anthocyanin-rich extract from pomace, which inhibited the QR activity. The QR induction for all samples varied with the concentration and there was an optimal concentration for which the QR induction was maximal. The technological process to manufacture cranberry juice had little influence on the overall QR inducer potencies of cranberry fractions, whereas the ability of phenols in fractions to stimulate the QR activity has been reduced significantly (P ≤ 0.05) during the technological process. Among all samples, phenolic compounds of eight fractions presented a maximum QR induction greater than 100 II(QR)/mg phenol. The phenolic compounds of the most polar fraction (rich in phenolic acids) and those of the less polar fraction (rich in proanthocyanidins) showed stronger induction than those observed with phenols from intermediate fractions.     

Concentration of flavonoids and phenolic compounds in aqueous and ethanolic propolis extracts through nanofiltration

Propolis has a variable and complex chemical composition with high concentration of flavonoids and phenolic compounds present in the extract. The extract varies with the solvent used in extraction. Ethanol extracts more phenolic acid and polar compounds than water. Before their use in industry, extracts must be concentrated but the use of high temperatures can degrade some compounds. Membrane processes is an option that allows concentration at low temperatures. Nanofiltration was carried out with aqueous and ethanolic extracts and each extract results in two distinct fractions: permeate and retentate. The capacity of the membrane to retain the compounds was verified by spectrophotometric analysis: for aqueous solution, the membrane retained around 94% of the phenolic compounds and 99% of the flavonoids, while for the ethanolic solution these values were 53% and 90%, respectively. Ferulic acid retention index was 1.00 and 0.88 to aqueous and ethanolic solutions, respectively. Thus, the nanofiltration process showed high efficiency in the concentration of propolis extracts.     

Simple phenolic content in olive oil residues as a function of extraction systems

Olive oil residues were tested for their composition in simple phenolic compounds as a function of the extraction system, i.e. the three- and two-phase centrifugation systems. Phenolic compound extraction with ethyl acetate was efficient and allowed recovery of 28.8 and 42.2% of total phenols present in dry olive oil residues originating from three-phase and two-phase systems, respectively. The qualitative and quantitative HPLC analyses of the extracts showed that hydroxytyrosol and p-tyrosol were the most abundant phenolic compounds. p-coumaric, caffeic, ferulic and vanillic acids were also present. The phenolic extract from the two-phase system had the highest concentration in hydroxytyrosol (1.16% (w/w) dry residue) and the strongest antioxidant activity. Olive oil residues were confirmed as a cheap source of large amounts of natural phenolic antioxidants.     

A Rapid High-Performance Liquid Chromatography Photodiode Array Detection Method to Determine Phenolic Compounds in Mung Bean (Vigna radiata L.)

A fast method was developed for simultaneous detection and quantification of 12 phenolic compounds in mung bean, using reversed phase high-performance liquid chromatography. The method was optimized for mobile phase combination, elution gradient, detection wavelength, and solvent extraction. All the phenolic compounds (gallic acid, neochlorogenic acid, catechin, chlorogenic acid, caffeic acid, p-coumaric acid, t-ferulic acid, vitexin, isovitexin, myricetin, quercetin, and kaempferol) were eluted for 18 min and recovered within a limit as per International Council for Harmonization guidelines. The method showed good linearity with correlation coefficient of 0.998. The limit of detection and quantification of all the compounds ranges from 0.27 ± 0.01 to 3.65 ± 0.3µg/mL and 0.91 ± 0.1 to 12.17 ± 0.9µg/mL, respectively. Vitexin (28.10 ± 0.20 to 29.60 ± 0.6 mg/100 g raw material) and isovitexin (34.09 ± 0.14 to 36.83 ± 0.82 mg/100 g raw material) were the major phenolic compounds along with other phenolic compounds found in mung beans.     

Comparison of processing treatments on the composition and functional properties of rapeseed preparations (Brassica campestris L. var. toria)

Rapeseed preparations viz. rapeseed meal, concentrates and isolates were prepared using different processing treatments involving organic solvents, acids, alkali, steaming and boiling. Their antinutritional constituents and functional properties were studied in comparison to undefatted meal. Percent decrease in phytic acid and phenolic content was maximum in seeds boiled for 30 min and isolates, respectively. Isolate II prepared by sodium hexa-metaphosphate had minimum glucosinolates, maximum content of total proteins and much improved nitrogen solubility, emulsifying and foaming properties. Water absorption and fat absorption capacities were enhanced by boiling seeds prior to grinding and ammonia-methanol extraction, respectively. Viscosity decreased in all the treatments as compared to control.     

Phenolic acid composition of sprouted wheats by ultra-performance liquid chromatography (UPLC) and their antioxidant activities

The phenolic acid profiles of flours from two Canadian wheat classes, Canadian Western Red Spring (CWRS) and Canadian Western Amber Durum (CWAD), were investigated using two different extraction mediums and analysed on an ultra-performance liquid chromatography (UPLC) system at different degrees of sprout damage. A sound (non-sprouted) control sample as well as two different sprouted sub-samples, derived from different germination protocols of the control, were prepared for both the CWAD and CWRS. Free phenolic acids were extracted from the ground whole wheat meal using three repetitive 80% ethanol extractions. Bound phenolic compounds were subsequently released from the residue by alkaline hydrolysis followed by triplicate extraction with diethyl ether:ethyl acetate (1:1, v/v). Twelve phenolic acid standards were clearly resolved and quantified using a short 5 min elution gradient. Seven phenolic acids (4-hydroxybenzoic, vanillic, caffeic, syringic, p-coumaric, ferulic and sinapic) were detected in the CWRS and CWAD alcoholic and alkaline extracts. Syringic acid was the main compound in the free phenolic alcoholic extracts of the wheat meal representing 77.0% and 75.3% of the total amount of detected free phenolic compounds for CWRS and CWAD, respectively. However, the major released phenolic compound detected in the alkaline hydrolysed extracts was ferulic acid accounting for 72.3% and 71.0% for CWRS and CWAD respectively total bound phenolics. During germination, syringic acid levels rose as the length of germination time increased, resulting in the increase in total phenolic compound and antioxidant activity of the sprouted wheat flours. There was an increase in total phenolic compounds and the antioxidant activity of the alcoholic extracts from the CWRS and CWAD wheat flours as the germination time was extended. As a result, the sprouted wheats exhibits better nutritional properties than un-germinated wheat and could be used to improve the nutrition value in food products.     

Supplementation of Ascophyllum nodosum meal and monensin: Effects on diversity and relative abundance of ruminal bacterial taxa and the metabolism of iodine and arsenic in lactating dairy cows

Previous research has shown that the brown seaweed Ascophyllum nodosum (ASCO) has antimicrobial and antioxidant properties and also increases milk I concentration. We aimed to investigate the effects of supplementing ASCO meal or monensin (MON) on ruminal fermentation, diversity and relative abundance of ruminal bacterial taxa, metabolism of I and As, and blood concentrations of thyroid hormones, antioxidant enzymes, and cortisol in lactating dairy cows. Five multiparous ruminally cannulated Jersey cows averaging (mean ± standard deviation) 102 ± 15 d in milk and 450 ± 33 kg of body weight at the beginning of the study were used in a Latin square design with 28-d periods (21 d for diet adaptation and 7 d for data and sample collection). Cows were fed ad libitum a basal diet containing (dry matter basis) 65% forage as haylage and corn silage and 35% concentrate and were randomly assigned to 1 of the following 5 dietary treatments: 0, 57, 113, or 170 g/d of ASCO meal, or 300 mg/d of MON. Supplements were placed directly into the rumen once daily after the morning feeding. Diets had no effect on ruminal pH and NH₃-N concentration, which averaged 6.02 and 6.86 mg/dL, respectively. Total volatile fatty acid concentration decreased linearly in cows fed incremental amounts of ASCO meal. Supplementation with ASCO meal did not change the ruminal molar proportions of volatile fatty acids apart from butyrate, which responded quadratically with the lowest values observed at 56 and 113 g/d of ASCO supplementation. Compared with the control diet or diets containing ASCO meal, cows fed MON showed greater molar proportion of propionate. Diets did not affect the α diversity indices Shannon, Simpson, and Fisher for ruminal bacteria. However, feeding incremental levels of ASCO meal linearly decreased the relative abundance of Tenericutes in ruminal fluid. Monensin increased the relative abundance of the CAG:352 bacterial genus in ruminal fluid compared with the control diet. Linear increases in response to ASCO meal supplementation were observed for the concentrations and output of I in serum, milk, urine, and feces. Fecal excretion of As increased linearly in cows fed varying amounts of ASCO meal, but ASCO did not affect the concentration and secretion of As in milk. The plasma activities of the antioxidant enzymes and the serum concentrations of thyroid hormones did not change. In contrast, circulating cortisol decreased linearly in diets containing ASCO meal. The apparent total-tract digestibilities of dry matter, organic matter, and crude protein increased linearly with ASCO meal, but those of neutral and acid detergent fiber were not affected. In summary, feeding incremental amounts of ASCO meal decreased serum cortisol concentration, and increased I concentrations and output in serum, milk, feces, and urine.     

Selection of the Solvent and Extraction Conditions for Maximum Recovery of Antioxidant Phenolic Compounds from Coffee Silverskin

The extraction of antioxidant phenolic compounds from coffee silverskin (CS) was studied. Firstly, the effect of different solvents (methanol, ethanol, acetone, and distilled water) on the production of antioxidant extracts was evaluated. All the extracts showed antioxidant activity (FRAP and DPPH assays), but those obtained with methanol and ethanol had significantly higher (p?<?0.05) DPPH inhibition than the remaining ones. Due to the lower toxicity, ethanol was selected as extraction solvent, and further experiments were performed in order to define the solvent concentration, solvent/solid ratio, and time to maximize the extraction results. The best condition to produce an extract with high content of phenolic compounds (13 mg gallic acid equivalents/g CS) and antioxidant activity [DPPH?=?18.24 μmol Trolox equivalents/g CS and FRAP?=?0.83 mmol Fe(II)/g CS] was achieved when using 60 % ethanol in a ratio of 35 ml/g CS, during 30 min at 60–65 °C.