不同干燥方法对西兰花中萝卜硫素含量影响

采用阴干、50℃~90℃烘干及晒干三种常用干燥方式干燥西兰花的花、茎、叶,采用HPLC测定萝卜硫素含量。西兰花不同部位中萝卜硫素含量是种子>花>茎>叶;而不同干燥方法中烘干最好,阴干最差,5种烘干温度中以90℃烘干时萝卜硫素含量最高。西兰花不同部位中种子萝卜硫素含量最高,有10.48 mg/g;而干燥方式采用90℃烘干最佳。     

β-Carotene and Ascorbic Acid Retention in Fresh and Processed Vegetables

Broccoli, carrots, and green beans (grown in 2 consecutive years) were randomly divided into 3 treatments: fresh-refrigerated (F-R), frozen (FZ) or canned (C) (carrots only). FZ or C vegetables were processed within 24 h and stored for up to 1 yr. F-R vegetables were held at 4 °C for 3 wk (broccoli and green beans) or 6 mo (carrots). Trans b-carotene (Tb-C) and total ascorbic acid (AA) were determined at specified times, before and after microwave cooking. Vitamin content differed between years due to environmental conditions. Blanching resulted in AA loss, but retention remained stable after freezing broccoli and green beans. F-R green beans lost >90% AA after 16 d storage. Linear decreases in AAwere found in most F-R or FZ vegetables. Tb-C decreased slightly during freezer storage. Reductions in Tb-C occurred in canned carrots. Microwave cooking had minimal effects on AA or Tb-C.     

Modifying the Processing and Handling of Frozen Broccoli for Increased Sulforaphane Formation

Frozen broccoli can provide a cheaper product, with a longer shelf life and less preparation time than fresh broccoli. We previously showed that several commercially available frozen broccoli products do not retain the ability to generate the cancer‐preventative agent sulforaphane. We hypothesized that this was because the necessary hydrolyzing enzyme myrosinase was destroyed during blanching, as part of the processing that frozen broccoli undergoes. This study was carried out to determine a way to overcome loss of hydrolyzing activity. Industrial blanching usually aims to inactivate peroxidase, although lipoxygenase plays a greater role in product degradation during frozen storage of broccoli. Blanching at 86 °C or higher inactivated peroxidase, lipoxygenase, and myrosinase. Blanching at 76 °C inactivated 92% of lipoxygenase activity, whereas there was only an 18% loss in myrosinase‐dependent sulforaphane formation. We considered that thawing frozen broccoli might disrupt membrane integrity, allowing myrosinase and glucoraphanin to come into contact. Thawing frozen broccoli for 9 h did not support sulforaphane formation unless an exogenous source of myrosinase was added. Thermal stability studies showed that broccoli root, as a source of myrosinase, was not more heat stable than broccoli floret. Daikon radish root supported some sulforaphane formation even when heated at 125 °C for 10 min, a time and temperature comparable to or greater than microwave cooking. Daikon radish (0.25%) added to frozen broccoli that was then allowed to thaw supported sulforaphane formation without any visual alteration to that of untreated broccoli.     

Broccoli seed extracts but not sulforaphane have strong free radical scavenging activities

The abilities of broccoli seed extracts and purified sulforaphane (SF) to scavenge 2,2′‐azinobis [3‐ethylbenzothiazoline‐6‐sulphonate] (ABTS^?+), 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH^?) and superoxide anions were studied. The free radical scavenging activities of broccoli seed extracts had no exact correlation with SF content, indicating that SF was not the main antioxidant component. The broccoli seed extracts were separated by high‐speed countercurrent chromatography to obtain purified SF, which showed dose‐dependent free radical scavenging activities in the DPPH^? and ABTS^?+ assays, but its activities were weaker to those of ascorbic acid. The same trend was observed in the chemiluminescence assay. The results showed that broccoli seed extracts had strong free radical scavenging activities that were not attributable to SF.     

MgSO4处理对西兰花芽苗菜生理活性物质和抗氧化能力的影响

本实验研究了外源喷施0、25、50、75 mmol/L的MgSO4对西兰花芽苗菜生长状况、生理活性物质含量和抗 氧化能力的影响。结果表明：MgSO4处理对西兰花芽苗菜造成了生长胁迫效应;叶绿素和总酚含量随着MgSO4浓度 的增大而增加,抗坏血酸含量却随着MgSO4浓度的增加而降低。发芽5 d的西兰花芽苗菜中总硫代葡萄糖苷（简称 硫苷）和萝卜硫素含量显著高于发芽8 d的,但发芽8 d的黑芥子酶活力高于发芽5 d的;MgSO4处理后,总硫苷和萝 卜硫素含量及黑芥子酶活力显著提高,但50 mmol/L和75 mmol/L MgSO4处理组之间差异不显著。MgSO4处理显著提 高了西兰花芽苗菜的抗氧化能力,但1,1-二苯基-2-三硝基苯肼自由基清除率在50 mmol/L和75 mmol/L处理组之间无 显著差异,H2O2清除率随MgSO4浓度的增加逐渐增强。因此,综合考虑,50 mmol/L MgSO4对于提高西兰花芽苗菜 的营养价值和保健功能是较适合的浓度。     

西兰花副产物中萝卜硫素提取、纯化及鉴定

以西兰花副产物为原料,研究萝卜硫素酶解浸提工艺,并通过单因素试验和响应面试验优化最佳工艺条件。在最佳条件的基础上进行放大实验,通过半制备高效液相色谱纯化和富集萝卜硫素,并应用超高效液相色谱-质谱联用技术对纯化物进行鉴定。结果表明：萝卜硫素最佳提取条件为酶解pH 5.0、酶解温度35 ℃、酶解时间67 min;在此条件下,萝卜硫素提取量为151.39 μg/g,与预测值（156.33 μg/g）无显著差异;纯化和富集后,得到28.62 mg/200 g萝卜硫素,回收率为94.52%,纯度为80.74%。根据萝卜硫素的二级质谱与碎片离子信息,进一步确定该纯化物为萝卜硫素。     

In vitro Inhibition of N-Nitrosomorpholine Formation by Fresh and Processed Tomatoes

We evaluated the ability of fresh tomatoes and processed tomato products (whole, diced, sauce, puree, and juice) to inhibit in vitro the formation of N-Nitrosomorpholine (NMOR), under conditions similar to the human stomach. The amount of NMOR that was formed averaged 23% to 82% that of the controls, on an equal wet weight basis, with paste being the most inhibitory. On an equal soluble solids basis, the amount of NMOR formed in the presence of products averaged 82% to 88% of that formed in the distilled water control. Fresh tomatoes showed greatest inhibition of nitrosation (NMOR formation averaged 80% of control), and processed tomatoes showed similar inhibition (NMOR 82% to 88% of the control). Ascorbic acid content was the strongest predictor of ability to inhibit NMOR formation. Processed tomato products inhibited nitrosation to a similar extent as had been reported for fresh tomatoes.     

气介式超声强化西兰花热风干燥过程中硫苷分解代谢途径相关物质的变化

为探究气介式超声对西兰花热风干燥过程中硫苷分解代谢的影响,本文研究了西兰花小花球在气介式超声联合热风干燥（20 kHz,60 ℃,125.2和180.1 W/dm2）过程中的干燥特性以及硫苷、萝卜硫素、抗坏血酸、Fe2+和酚酸含量以及黑芥子酶、体外抗氧化活性的变化规律。结果表明:相比于单独热风干燥,超声处理不仅可以加快干燥进程（125.2和180.1 W/dm2超声处理下干燥时间分别比单独热风干燥缩短11.1%和17.8%）,同时,超声联合热风干燥过程中3-吲哚甲基硫苷含量增加且黑芥子酶活力增强。180.1 W/dm2气介式超声联合热风干燥终点样品中3-吲哚甲基硫苷、萝卜硫素含量和黑芥子酶活力分别比单独热风干燥终点的样品高出10.7%、26.0%和15.2%,Fe2+含量比单独热风干燥终点的样品低8.1%,表明超声处理减少了Fe2+对硫苷酶促降解的干扰,能够促进4-甲基硫氧丁基硫苷降解形成萝卜硫素,但超声处理对西兰花干燥过程中抗坏血酸含量、游离酚酸含量和体外抗氧化活性变化影响不明显。本研究表明气介式超声联合热风干燥既能加快西兰花干燥进程,又能促进4-甲基硫氧丁基硫苷的转化,并对生物活性成分具有一定的保护作用。     

天然抗氧化植物化学物的研究进展

近年来大量研究发现,许多水果、蔬菜和中草药中富含具有抗氧化能力的植物化学物,它们能够保护机体,抵抗各种各样的疾病。因此,含有这些植物化学物的食品引起了消费者的关注,同时也成为科研工作者研究开发的热点。阐述近年来国内外对抗氧化植物化学物方面的一些研究进展,包括植物化学物抗氧化活性的评估、植物化学物的提取和分离。     

轮叶党参的植物化学物及生物活性研究进展

轮叶党参是桔梗科党参属多年生蔓生草本,长白山珍贵的山野菜和中药材。轮叶党参具有广泛的药理作用及调节生理功能的作用,近年来其中的植物化学物及其生物活性备受关注。本文对目前轮叶党参中的植物化学物质分离鉴定及生物活性研究概况进行概述,包括植物化学物及其代谢产物、生物发酵及生物活性,以期为轮叶党参资源应用提供一定的理论依据。     

高效液相色谱法测定西兰花中萝卜硫素的研究

建立了采用高效液相色谱法(HPLC)测定西兰花种子及芽苗中萝卜硫素的方法。具体方法为:采用反相XDB-C18色谱柱分离,乙腈-水梯度(10%-60%-100%,0-25-30min)洗脱,流速0.6mL/min,检测波长254nm,进样量50μL。萝卜硫素测定结果的相对标准偏差小于1%,平均回收率达到97.14%。该方法具有较好的分离效果和较高的稳定性,适用于西兰花中萝卜硫素含量的测定。     

Health-related Interactions of Phytochemicals

ABSTRACT: Interactions between phytochemical components often modify the pharmacological effects of botanical dietary supplements, functional foods, or drugs. These interactions can either potentiate the effect of bioactive phytochemicals or interfere with their activity. This review defines and explores 2 types of phytochemical interactions: endointeractions that occur between components within a plant species and exointeractions that occur between components from different plants or between plants and synthetic drugs. Exointeractions and endointeractions between and within the complex mixtures of phytochemicals may have a profound effect on human health. Few well-characterized interactions were shown to affect a wide range of biological processes such as metabolism, bioavailability, solubility, cellular uptake and efflux, and body clearance. Phytochemical interactions may explain the health effects of regional diets, undesirable side effects of drugs, and inconsistent performance of dietary supplements. Better understanding of health-related phytochemical interactions should lead to a more sophisticated, holistic approach to disease prevention and treatment.     

Effect of Maturity Stages and Drying Methods on the Retention of Selected Nutrients and Phytochemicals in Bitter Melon (Momordica charantia) Leaf

ABSTRACT:  The purpose of this study was to investigate the nutrient and phytochemical composition of bitter melon leaves under varying maturity levels and drying techniques. Fresh, oven-dried, and freeze-dried leaves were evaluated over 3 maturity stages. In fresh leaves at various stages, crude fat, crude protein, and soluble dietary fiber contents ranged from 4.2% to 13.6%, 6.4% to 23.1%, and 0.04% to 3.50% on dry-weight basis, respectively. The contents of K, Ca, Mg, Fe, and Zn ranged from 1850.8 to 2811.8, 837.4 to 4978.2, 317.3 to 512.4, 8.4 to 16.7, and 4.1 to 5.9 mg/100 g dry-weight basis, respectively. Vitamin C, β-carotene, and lutein contents ranged from 397.4 to 1275.1, 154.2 to 422.8, and 737.6 to 1304.6 μg/g dry-weight basis. The major flavonoids and phenolic acids were rutin, gentistic acid, and  o -coumaric acid, which ranged from 7.57 to 12.75, 2.53 to 10.11, and 4.24 to 9.75 mg/g dry-weight basis, respectively. In oven-dried samples, 40.2% to 52.3% of vitamin C, 35.4% to 55.4% of β-carotene, 25.6% to 71.6% of lutein, 26.4% to 84.0% of rutin, trace to 11.4% of gentistic acid, and 7.4% to 46.6% of  o -coumaric acid were retained, while the retainment ratios of these components in freeze-dried samples were 84.7% to 99.0%, 76.4% to 99.3%, 90.4% to 96.1%, 39.8% to 99.3%, 24.1% to 68.4%, and 75.8% to 87.0%, respectively. The data showed that freeze-drying better preserves the nutrient and phytochemical quality of bitter melon leaves in comparison to oven-drying. Bitter melon leaf is a rich source of selected nutrients and phytochemicals.     

Phytochemicals: nutraceuticals and human health

Phytochemicals, as plant components with discrete bio‐activities towards animal biochemistry and metabolism are being widely examined for their ability to provide health benefits. It is important to establish the scientific rationale to defend their use in foods, as potential nutritionally active ingredients. Phytochemicals could provide health benefits as: (1) substrates for biochemical reactions; (2) cofactors of enzymatic reactions; (3) inhibitors of enzymatic reactions; (4) absorbents/sequestrants that bind to and eliminate undesirable constituents in the intestine; (5) ligands that agonize or antagonize cell surface or intracellular receptors; (6) scavengers of reactive or toxic chemicals; (7) compounds that enhance the absorption and or stability of essential nutrients; (8) selective growth factors for beneficial gastrointestinal bacteria; (9) fermentation substrates for beneficial oral, gastric or intestinal bacteria; and (10) selective inhibitors of deleterious intestinal bacteria. Such phytochemicals include terpenoids, phenolics, alkaloids and fiber. Research supporting beneficial roles for phytochemicals against cancers, coronary heart disease, diabetes, high blood pressure, inflammation, microbial, viral and parasitic infections, psychotic diseases, spasmodic conditions, ulcers, etc is based on chemical mechanisms using in vitro and cell culture systems, various disease states in animals and epidemiology of humans. However, it must be emphasized that a distinction needs to be drawn between the types of information that can be obtained from studies in vitro, in animals and in humans. Mechanisms of action must certainly be established in vitro; however, the efficacy of these same ingredients with their mechanisms of action, must also be demonstrated in vivo. The rapid growth in the use of phytochemicals in nutraceutical and functional foods requires that the food and pharmaceutical industries face new challenges: in addressing worldwide public concern over the efficacy and safety of supplements and foods claimed to be health‐promoting; in government regulations related to safety, labeling and health claims for products that contain phytochemicals; in the manufacturing of foods with different qualities and stabilities; and in marketing issues, particularly as they relate to consumers' recognizing added value. © 2000 Society of Chemical Industry     

Heat Transfer during Blanching and Hydrocooling of Broccoli Florets

The objective of this work was to simulate heat transfer during blanching (90 °C) and hydrocooling (5 °C) of broccoli florets (Brassica oleracea L. Italica) and to evaluate the impact of these processes on the physicochemical and nutrimental quality properties. Thermophysical properties (thermal conductivity [line heat source], specific heat capacity [differential scanning calorimetry], and bulk density [volume displacement]) of stem and inflorescence were measured as a function of temperature (5, 10, 20, 40, 60, and 80 °C). The activation energy and the frequency factor (Arrhenius model) of these thermophysical properties were calculated. A 3‐dimensional finite element model was developed to predict the temperature history at different points inside the product. Comparison of the theoretical and experimental temperature histories was carried out. Quality parameters (firmness, total color difference, and vitamin C content) and peroxidase activity were measured. The satisfactory validation of the finite element model allows the prediction of temperature histories and profiles under different process conditions, which could lead to an eventual optimization aimed to minimize the nutritional and sensorial losses in broccoli florets.     

Determination and Health Implication of the Erucic Acid Content of Broccoli Florets, Sprouts, and Seeds

The erucic acid content of broccoli florets, sprouts, and seeds was found to be about 0.8, 320, and 12100 mg/100 g, respectively. Using the erucic acid limit established for canola oil in the U.S.A. and Canada as a guideline, the estimated dietary intake of erucic acid from florets and sprouts was considered of little consequence, whereas in seeds a relatively small amount (about 35 g/wk) equaled our calculated exposure limit for erucic acid. Additionally, the most complete fatty acid distribution yet published for the various forms of broccoli are presented.     

臭氧在鲜切西兰花保鲜中应用的研究

本实验用臭氧水对鲜切西兰花进行浸泡处理,以探讨其对鲜切西兰花表面微生物的杀灭作用及对鲜切西兰花贮藏过程中品质的影响。实验结果表明,臭氧水浸泡处理能有效控制鲜切西兰花表面的微生物,并降低多酚氧化酶活性,保护VC,抑制叶绿素的降解,但对还原糖有一定的影响。其中浓度为2.40×10-6的臭氧水处理使菌落总数降低了一个数量级,酶活降低40%,在贮藏末期叶绿素含量比对照高53%。     

西兰花中的抗癌成分及其活性的初步研究

目的：本实验对西兰花所含有的抗癌成分进行研究。 方法：新鲜西兰花花蕾的甲醇提取物用乙酸乙酯和n-丁烯醇萃取后,通过硅胶层析、薄层层析、高效液相等进行分离、提纯,得到化合物A、B。然后利用NMR、FAB-MS等仪器分析,确定其结构,并用免疫印迹法测得其抗癌活性。 结果：经过仪器分析,确定这两种抗癌活性成分为单亚麻酰甘油和单亚油酰甘油,在浓度为140mol/L和150mol/L时能抑制Raji细胞EB病毒早期抗原的合成。 结论：日常食用的绿色蔬菜中含有抗癌活性成分,可以通过日常饮食的摄入达到防癌的目的。