气相色谱法测定甘蓝中啶虫脒残留量

用气相色谱分析法快速测定啶虫脒。甘蓝预制样品经高速匀浆法提取、弗罗里硅土层析柱净化后用附带ECD检测器的气相色谱仪检测啶虫脒的残留量,外标法定量,回收率为80.2?.8%,最低检出浓度为0.001mg/kg,测定结果的相对标准偏差不大于3.4%。     

梯度淋洗离子色谱法同时检测西兰花中6种无机阴离子

构建一种利用梯度淋洗离子色谱技术分析西兰花中Cl^-、Br^-、NO₂^-、NO₃^-、PO₄^3-和SO₄^2-6种无机阴离子含量的方法。梯度淋洗色谱离子体系为DIONEX Ion Pac AS11-HC(4 mm×250 mm)色谱柱,流速1.0 mL/min,抑制器电流80 mA,KOH淋洗液梯度淋洗。6种阴离子线性相关系数0.9995~0.9999,相对标准偏差(RSD)<2.5%,加标回收率95.7%~104%。用于检测西兰花中无机阴离子的方法灵敏度高、回收率高、可以适用于西兰花中6种阴离子精确定量分析。     

Isolation of sinapic acid from broccoli using molecularly imprinted polymers

A molecularly imprinted polymer was synthesized for the purpose of sinapic acid isolation from Egyptian nutraceutical Botrytis italica, L. (broccoli) due to its prominent medicinal and wide pharmacological activities. A computational study was first developed to determine the optimal template to functional monomer molar ratio. Based on the computational results, five polymers were synthesized using a bulk polymerization method with sinapic acid as the template molecule. Evaluation of the synthesized polymers binding performance was carried out using batch rebinding assay, which revealed that the molecularly imprinted polymer of molar ratio (1:4:20), template to functional monomer (4‐vinyl pyridine) to crosslinker (ethylene glycol dimethacrylate) was of optimum performance, thus, this polymer was applied for sinapic acid isolation from closely related analogues. This represents a more practical approach to isolate sinapic acid from different natural extracts selectively.     

Physicochemical Properties and Antioxidant Activity of Spray-Dry Broccoli (Brassica oleracea var Italica) Stalk and Floret Juice Powders

This research presents the microencapsulation and conservation of antioxidants of broccoli juice processed by spray drying, and proposes the use of a by-product as a technological application. Broccoli juice (BJ) extracted from two sources, stalks and florets, was spray-dried employing maltodextrin (MX) as a carrier agent at concentrations of 5, 7.5, and 10%, and inlet temperatures of 150 and 220 °C. The total phenolic content (TPC), and antioxidant activity (AA) of the BJ-MX powders were determined together with the physicochemical characteristics, including particle morphology, microstructure, and thermal properties. Based on the TPC and AA, the optimal processing conditions found were 5% of MX and a drying temperature of 220 °C. However, the florets showed higher TPC, while stalks presented higher AA under those processing conditions. The particles exhibited micrometric sizes and a mixture of spherical-shape particles and pseudo-spherical particles. The diffractograms indicated an amorphous microstructure in all samples. The glass transition temperature (Tg) was determined in the range of 50 °C for the samples dried at 150 °C and 55 °C for those dried at 220 °C. This suggested that powders might be stored at temperatures below the Tg without presenting any loss of antioxidants.     

HPLC method validation for measurement of sulforaphane level in broccoli by‐products

A simple and specific analytical method was developed and tested for the determination of sulforaphane in broccoli by‐products. The method includes the optimization of the conversion of glucoraphanin to sulforaphane, followed by purification of extracts using solid‐phase extraction and high‐performance liquid chromatography (HPLC) analysis. The response surface methodology was used to find optimum conditions for the preparation and purification procedure. Chromatographic conditions for reversed‐phase HPLC with UV photodiode array detection were as follows: column, Exil ODS C₁₈, 25 × 0.46 cm, 5 μm; column temperature, 36°C; mobile phase, a 30 : 70 (v/v) mixture of acetonitrile:water; flow rate, 0.6 mL/min. The detection wavelength was UV 202 nm. Under these conditions, excellent linearity was obtained (r² = 1), and the overall recovery was 97.5 and 98.1% for fresh florets and lyophilized florets, respectively. The precision results showed that the relative standard deviation of the repeatability for florets fresh and lyophilized was 3.0 and 4.0%, respectively. Sulforaphane contents were determined in the edible portion of fresh broccoli, and broccoli crop remains. Copyright © 2009 John Wiley & Sons, Ltd.     

Green synthesis of ZnO nanoparticles using aqueous Brassica oleracea L. var. italica and the photocatalytic activity

ABSTRACT

This study reports the synthesis of ZnO nanoparticles using the aqueous solution of broccoli extract. The nanoparticles, represented as broc-ZnO (with broccoli extract) and nb-ZnO (without broccoli extract), were obtained after calcination. The nanoparticles were characterized using X-ray diffraction (XRD), Transmission electron microscopy (TEM), Fourier Transform infra-red (FTIR), Energy dispersive spectroscopy (EDX), UV-visible spectroscopy (UV) and Photoluminescence (PL). Hexagonal phases were identified for both nanoparticles, while average crystallite sizes of 14 and 17?nm for broc-ZnO and nb-ZnO, respectively, were obtained. UV studies indicated the bandgap of the broc-ZnO and nb-ZnO as 4.09 and 3.87?eV, respectively. A plausible mechanism for the synthesis of the nanoparticles was suggested. The photocatalytic efficiency of broc-ZnO, obtained via the broccoli extract, was evaluated by studying its photo-enhanced catalytic activity against methylene blue (MB) and phenol red (PR), under UV light irradiation and 74% and 71% degradation efficiency of the successive dyes were achieved.     

矮壮素处理对青花菜生长状态及春化关键酶活性的影响

以中早熟品种‘元绿701’青花菜为试材,当植株长至3片真叶时叶面喷施不同浓度(2 000、3 000、4 000mg·L-1)的矮壮素溶液,在其长到6片真叶时进行低温春化处理(昼温/夜温=(13.3±0.5)℃/(6.3±0.5)℃),研究矮壮素处理对青花菜生长状态及春化相关酶活性的影响.结果表明:喷施矮壮素后,改变了植株的营养生长状态,使株高显著降低、茎粗显著增加;降低了转化酶和硝酸还原酶的活性,提高了谷氨酰胺合成酶活性.低水平的转化酶、硝酸还原酶、谷氨酰胺合成酶活性有利于春化的完成.     

Optimization of an Extraction Process to Obtain a Food-Grade Sulforaphane-Rich Extract from Broccoli (Brassica oleracea var. italica)

Sulforaphane (SFN) is a powerful health-promoting compound found in broccoli in the form of its inactive precursor, glucoraphanin (GFN). SFN formation occurs through the enzymatic hydrolysis of glucoraphanin by myrosinase under specific chemical conditions. Its incorporation in food formulations has been hindered by the thermal instability of SFN and low concentration in Brassicaceae. Then, extracting SFN from broccoli at a temperature below 40 °C appears as an option to recover and stabilize SFN, aiming at delivering it as a nutraceutical. We studied an eco-friendly extraction process to obtain an SFN-rich extract from broccoli. The effect of the broccoli mass/solvent ratio, ethanol concentration in the extractant solution, and extraction time on the recovery of SFN, GFN, phenolic compounds, and antioxidant activity were studied through a Box–Behnken design. The regression models explained more than 70% of the variability in the responses, adequately representing the system. The experimental factors differently affected the bioactive compound recovery and antioxidant activity of the extracts. The extraction conditions that allowed the highest recovery of bioactive compounds and antioxidant activity were identified and experimentally validated. The results may provide the basis for the design of a process to produce a sulforaphane-rich food supplement or nutraceutical by using a GRAS extractant.