乙醇熏蒸处理对鲜切西兰花活性成分和抗氧化活性的影响

研究乙醇熏蒸处理对鲜切西兰花总酚、总黄酮、总硫代葡萄糖苷和萝卜硫素等活性成分含量及抗氧化活性的影响。先将花球在20 ℃条件下分别用体积分数为2%、5%、10%、20%乙醇溶液熏蒸处理6 h,再切割成小花并在10 ℃条件下贮藏。结果表明,10%乙醇溶液熏蒸处理可以显著延长鲜切西兰花的货架期、提高总酚和总黄酮含量、延缓总硫代葡萄糖苷和萝卜硫素含量下降,并可有效保持较高的DPPH（1,1-diphenyl-2-picrylhydrazyl）自由基清除能力和还原力,提高其清除超氧阴离子自由基和羟自由基能力,从而延缓西兰花采后衰老、保持较高的抗氧化活性。同时发现,总酚、总黄酮和萝卜硫素含量与DPPH自由基清除能力存在极显著的正相关性。这些结果表明乙醇熏蒸处理在鲜切西兰花保鲜中具有较好的应用前景。     

高温及其联合亚硒酸钠调控西兰花芽苗生理及异硫氰酸酯代谢研究

为研究高温及其联合亚硒酸钠对西兰花芽苗生理和异硫氰酸酯代谢的影响,通过高温胁迫及其联合0.1 mmol/L亚硒酸钠处理西兰花芽苗,分析发芽期间芽苗主要生理生化和异硫氰酸酯代谢的变化。结果显示,相较蒸馏水处理,西兰花芽苗发芽期间经高温胁迫及其联合亚硒酸钠处理,其生长发育受到抑制,发芽4、6 d时芽长显著降低(P<0.05),分别为蒸馏水处理组的79.39%和57.45%;发芽4 d时,丙二醛含量显著增加(P<0.05),为对照的1.67倍;4 d时芽苗总抗氧化能力也显著增加(P<0.05),为对照的1.56倍。高温及其联合亚硒酸钠处理下芽苗中异硫氰酸酯含量均显著提高(P<0.05),发芽4 d时其含量分别为对照的2.36倍和3.35倍,其后随发芽时间延长异硫氰酸酯含量显著降低(P<0.05)。亚硒酸钠处理4 d,芽苗中硫代葡萄糖苷含量显著高于对照处理(P<0.05),而黑芥子酶无显著变化(P>0.05),研究表明西兰花芽苗经高温联合亚硒酸钠处理是富集异硫氰酸酯和硫代葡萄糖苷的有效方式,且发芽时间以4 d为宜。     

响应面法优化西兰花芽苗富集异硫氰酸酯发芽工艺

为优化ZnSO₄与褪黑素联合处理下西兰花富集异硫氰酸酯的工艺条件。以西兰花发芽期间的异硫氰酸酯含量、芽长和鲜重为指标,先通过单因素实验研究发芽温度、发芽时间、ZnSO₄处理浓度和褪黑素处理浓度对异硫氰酸酯含量和芽长及鲜重的影响,并在此基础上进一步通过响应面试验对其优化,同时分析异硫氰酸酯代谢相关指标的变化。实验结果显示,发芽温度、ZnSO₄和褪黑素处理浓度及发芽时间均对西兰花富集异硫氰酸酯有显著影响。响应面试验优化得到了最优发芽工艺条件,西兰花发芽期间经4.69 mmol/L ZnSO₄联合13.18 μmol/L褪黑素处理,于30 ℃发芽3 d时异硫氰酸酯含量达到最高,为451.27 mg/100 g m_f。ZnSO₄联合褪黑素处理的西兰花芽苗中硫代葡萄糖苷和萝卜硫素含量以及黑芥子酶活性均显著高于对照组（P<0.05）。本研究表明ZnSO₄联合褪黑素处理是富集西兰花芽苗中异硫氰酸酯的有效手段,优化得到的发芽工艺可为生产富含异硫氰酸酯的西兰花芽苗提供技术支撑。     

体外消化对银杏果酚类物质含量及其抗氧化活性的影响

银杏果富含多种营养成分,具有良好的抗氧化活性。研究探讨了体外模拟消化处理对银杏果酚类物质含量及其抗氧化活性的影响。采用福林酚和氯化铝-亚硝酸钠比色法考察消化处理对银杏果总酚和总黄酮含量的影响,通过FRAP铁离子还原能力和ABTS自由基清除能力考察消化处理对银杏果抗氧化活性的影响。结果表明,模拟胃液消化处理能增加银杏果总黄酮含量,但对总酚含量影响不显著,然而模拟肠液消化处理会增加银杏果总酚和总黄酮的含量。模拟胃液处理能显著提高银杏果的FRAP抗氧化能力与ABTS抗氧化能力,模拟肠液处理能显著提高其FRAP抗氧化能力,但对其ABTS抗氧化能力影响不显著,抗氧化活性可能与其酚类物质含量和组成有关。研究为银杏果的开发利用提供了技术支撑和理论依据。     

白光和红光光周期对西兰花芽苗菜生理生化和萝卜硫苷代谢的影响

本文研究了白光和红光不同光周期（0、4、8、12、16和20 h·d?1）对西兰花芽苗菜生长、可溶性糖、可溶性蛋白、抗坏血酸、花色苷和萝卜硫苷代谢的影响。结果表明:光照抑制西兰花芽苗的生长,红光较白光处理能够促进西兰花芽苗芽长增长;随着光周期的延长,西兰花芽苗菜中可溶性糖、可溶性蛋白、抗坏血酸、萝卜硫苷和总硫苷含量、黑芥子酶活力以及萝卜硫素含量均呈现先增加后降低的趋势。相较于白光,红光明显提高了西兰花芽苗菜中可溶性糖、可溶性蛋白、抗坏血酸和萝卜硫苷含量。但白光处理下花色苷含量明显高于红光处理。在光周期小于12 h·d?1时,红光处理下萝卜硫素形成量显著高于白光处理（P<0.05）,而当光周期大于12 h·d?1时,红光处理下萝卜硫素形成与白光处理之间差异不显著甚至低于白光处理。总之,红光相较于白光更有利于提高西兰花芽苗菜的产量和营养品质,12 h·d?1是比较适合的光周期。     

NaCl胁迫对西兰花芽苗叶黄素积累及抗氧化能力的影响

为探究NaCl胁迫对西兰花芽苗叶黄素富集及抗氧化能力的影响,本实验以“青峰”西兰花种子为实验原材料,研究了不同浓度NaCl溶液处理对西兰花芽苗的芽长、鲜重、干重、含水率、可溶性蛋白、还原糖、丙二醛、脯氨酸、叶黄素含量及抗氧化酶[超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）]活性的影响。结果表明,不同NaCl浓度对西兰花芽苗生长影响较大,随NaCl浓度由0~300 mmol/L变化,叶黄素含量先升高后下降。经100 mmol/L NaCl胁迫处理至第4 d收获的芽苗中叶黄素含量为546.25 μg/g,比对照组增加了37.54%,该条件下芽苗的芽长、鲜重、干重、含水率、可溶性蛋白、还原糖含量也均明显提高,较对照组分别增加了20.88%、161.16%、68.65%、2.86%、54.90%和40.0%,SOD、POD、CAT抗氧化酶活性与对照组相比分别增加了36.26%、14.62%、32.34%。本研究为通过NaCl胁迫西兰花种子萌发来提高叶黄素含量提供了新的方式,为开发功能性西兰花芽苗食品提供参考。     

两种芦笋不同部位酚类物质及抗氧化活性研究

采用超声辅助法提取白芦笋茎、白芦笋尖、绿芦笋茎和绿芦笋尖中的酚类物质,通过比色法及高效液相色谱(high performance liquid chromatography,HPLC)法测定各提取物中总酚、总黄酮、总单宁、缩合单宁和芦丁含量及其抗氧化能力(DPPH自由基、ABTS自由基清除活性和还原力),并探究芦笋酚类物质与抗氧化能力之间的相关性。结果表明,两种芦笋中均不含单宁类物质;绿芦笋尖中总酚、总黄酮、芦丁含量最高,3种抗氧化活性均最强,其后依次为绿芦笋茎、白芦笋尖和白芦笋茎。HPLC指纹图谱显示,绿芦笋尖中酚类物质的种类及含量均最高,白芦笋茎中则最少。以上结果说明绿芦笋比白芦笋中酚类物质更多,抗氧化性更强,且芦笋尖中酚类含量及抗氧化性优于芦笋茎。相关性分析发现,芦笋中总酚、总黄酮、芦丁、DPPH自由基和ABTS自由基清除能力两两之间均显著正相关,表明芦笋中酚类物质与自由基清除能力关系密切。     

微酸性电解水对苦荞芽活性成分及抗氧化能力的影响

以苦荞为原料,将不同有效氯浓度（available chlorine concentration,ACC）的微酸性电解水（slightly acidic electrolyzed water,SAEW）应用于芽苗菜生产,研究其对苦荞芽活性成分及其抗氧化能力的影响。结果表明：SAEW处理组苦荞芽活性成分含量相比对照组有所增加,ACC为20 mg/L的SAEW处理的苦荞芽总酚、总黄酮及芦丁含量相比自来水对照组分别提升了28.69%、26.19%和29.08%。SAEW处理萌发的苦荞芽在生长7 d内苯丙氨酸解氨酶比活力均高于自来水对照组。苦荞芽的抗氧化活性物质含量与其抗氧化能力间呈显著正相关。     

西兰花种子发芽过程中生理活性物质含量的变化

以西兰花种子为试材,测定不同品种西兰花种子中萝卜硫苷和萝卜硫素含量,分析选取的种子在发芽过程中抗坏血酸、总酚、花色苷、萝卜硫苷、黑芥子酶活性和萝卜硫素含量的变化。结果表明,10种西兰花种子中萝卜硫苷和萝卜硫素含量差异显著,两者在LX5种子中含量最高,分别为134.06μmol/g DW和11.37 mg/g DW,且硫苷水解的产物中萝卜硫素的含量最高。LX5中,抗坏血酸在发芽过程中逐渐生成,发芽4 d时高达127.49mg/100 g FW,随后逐渐下降;总酚在发芽过程中逐渐下降,发芽5 d时其含量下降42.14%;花色苷含量与抗坏血酸含量变化趋势基本一致;萝卜硫苷和萝卜硫素含量在发芽过程中呈下降趋势;黑芥子酶活性在0~3 d无显著变化,随后逐渐增强。     

不同处理对苹果抗氧化活性的影响

研究不同处理对苹果抗氧化活性的影响,对苹果分别进行削皮、榨汁、杀菌处理,测定各样品V_C、总酚、总黄酮含量及抗氧化活性,同时分析各指标间的相关性。结果表明,各样品抗氧化活性大小依次为果皮整果果渣果肉果汁杀菌果汁;果皮的V_C、总酚、总黄酮含量均高于其他样品;苹果V_C、总酚、总黄酮及抗氧化活性之间呈显著正相关。因此为了具有最大抗氧化活性,建议人们带皮食用苹果。     

发芽条件对西兰花芽苗菜总黄酮富集的影响

为富集西兰花芽苗菜总黄酮,研究不同消毒方法(物理消毒、物理化学联合法)对西兰花种子消毒效果的影响以及不同培养条件下总黄酮含量的变化。以西兰花种子为试材,通过单因素试验(浸泡温度、浸泡时间、发芽温度、发芽时间)与正交试验对发芽条件进行优化。结果表明,紫外消毒10 min联合1%食品级奥克泰士D10消毒效果好,发芽率最高;西兰花富集总黄酮的最适发芽条件为:浸泡温度25℃、浸泡时间6 h、发芽温度20℃、发芽时间4 d。在最佳工艺条件下,西兰花芽苗总黄酮含量为11.33 mg/g。     

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。     

Intensifying sulforaphane formation in broccoli sprouts by using other cruciferous sprouts additions

Sulforaphane is a significant chemopreventive compound which is the predominant glucosinolate in broccoli sprouts. However, the existence of the epithiospecifier protein could direct the hydrolysis of glucosinolates toward sulforaphane nitrile formation instead of sulforaphane. Therefore, the study aimed on improving the yielding of sulforaphane in broccoli sprouts with a new method of the united hydrolysis of cruciferous sprouts. According to the results, the addition of radish, rocket and rape sprouts to broccoli sprouts could promote the hydrolysis of the glucoraphanin to anticancer effective sulforaphane to 2.03, 2.32 and 1.95-fold, respectively, compared to single broccoli sprouts. Meanwhile, the formation of non-bioactive sulforaphane nitrile in these three groups decreased greatly. However, the addition of mustard sprouts had no positive effect. These observations could make a contribution to the potential chemoprotective effects of broccoli sprouts.     

A comparative study on the polyphenolic content,antibacterial activity and antioxidant capacity of different solvent extracts of Brassica oleracea vegetables

Brassica vegetables are rich in polyphenols, flavonoids and glucosinolates. Investigation was undertaken to optimise the best solvents among 60% ethanol, acetone and methanol for the extraction of polyphenols from Brassica vegetables. Furthermore, different properties such as antibacterial activity and antioxidant capacity were also investigated. Results showed that a 60% methanolic extract showed the highest total phenolic content which was 23.6, 20.4 and 18.7 mg gallic acid equivalents (GAE) g^?1 extract for broccoli, Brussels sprouts and white cabbage, respectively. The hydroxybenzoic acid content of various solvent extracts ranged from 5.86 to 8.91 GAE g^?1 extract for broccoli, 2.70 to 5.44 GAE g^?1 extract for Brussels sprouts and 3.69 to 4.86 GAE g^?1 extract for white cabbage, while the hydroxycinnamic acid content ranged from 0.78 to 1.26 chlorogenic acid equivalents (CAE) g^?1 extract for broccoli, 1.41 to 3.45 CAE g^?1 extract for Brussels sprouts and 0.49 to 1.14 CAE g^?1 extract for white cabbage. A concentration‐dependent antioxidative capacity was confirmed for different reactive oxygen species, and moderate antibacterial activity was observed against a number of Gram‐negative and Gram‐positive food spoilage and food pathogenic bacteria. Solvents significantly affected polyphenolic content and its different properties, and the methanol was found to be the best solvent for the extraction of polyphenols from studied Brassica vegetables.     

Effect of nitrogen and sulfur fertilization on glucosinolates in the leaves and roots of broccoli sprouts (Brassica oleracea var. italica)

Broccoli (Brassica oleracea L. var. italica cv. Marathon) sprouts are a rich source of glucosinolates, particularly 4‐methylsulfinylbutyl glucosinolate (glucoraphanin), the precursor of the chemoprotective isothiocyanate, sulforaphane. Sulfur and nitrogen fertilization have been shown to influence the pattern and levels of glucosinolates in mature broccoli, but little information is available on the fertilization of sprouts, a transient stage of broccoli growth, which have been recommended for salads. Therefore, an experiment was set up to evaluate the effect of N and S fertilization on the glucosinolate content of the aerial part and roots of broccoli sprouts. Nitrogen was tested at 0, 45.5, 91.0 mg L^?1 and sulfur at 0, 14.6 and 29.2 mg L^?1. The results showed that total glucosinolates in the aerial part were significantly higher (P < 0.001) than in the roots. The major glucosinolates in the aerial part were 4‐methylsulfinylbutyl and 3‐methylsulfinylpropyl whereas in the roots they were 2‐phenylethyl and 4‐methylthiobutyl. Fertilization of broccoli sprouts had a significant (P < 0.001) detrimental effect on the levels of aliphatic glucosinolates whereas the opposite was noted for indole and aromatic glucosinolates, for some of the fertilization combinations tested. Overall, the results indicate that broccoli sprouts do not benefit from fertilization. Copyright © 2006 Society of Chemical Industry     

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.