花生红衣中原花青素A1的分离鉴定及其对丙烯酰胺的抑制效果

以花生红衣原花青素（peanut skin procyanidins,PSP）混合物经过凝胶色谱分离后得到的第4个级分PSP-4为原料,通过制备型高效液相色谱分离得到1?种原花青素,记为PSP-4-1,并利用液相色谱-四极杆飞行时间质谱及核磁共振技术鉴定其结构。分别比较其在化学模拟体系和炸薯条食品体系中对丙烯酰胺的抑制效果。结果表明：分离制备得到的PSP-4-1结构为表儿茶素-（2β→O→7,4β→8）-儿茶素（原花青素A1）,在化学模拟体系和炸薯条食品体系中对丙烯酰胺的抑制均呈非线性的质量浓度-抑制率关系,在化学模拟体系中,原花青素A1添加质量浓度为0.05?mg/mL时抑制率可达（58.10±3.86）%,在炸薯条食品体系中原花青素A1添加质量浓度为0.03?mg/mL时抑制率可达（57.16±2.61）%。这一研究对于开发一种高效、经济的丙烯酰胺抑制剂具有指导意义。     

花生红衣中黄烷醇抑制丙烯酰胺效果及其分离鉴定

目的研究花生红衣中提纯的原花青素(peanut skin procyanidins,PSPs-1)在化学模拟体系和食品体系中对丙烯酰胺产生的抑制效果,并对PSPs-1的组成成分进行鉴定。方法以天冬酰胺和葡萄糖反应产生丙烯酰胺作为化学模拟体系,以油炸薯条生成丙烯酰胺作为食品体系,通过HPLC分析PSPs-1对2种体系中丙烯酰胺的抑制效果,并采用反相高效液相色谱-电喷雾-质谱联用(RP-HPLC-ESI-MS/MS)技术对PSPs-1进行鉴定。结果在化学模拟体系中,PSPs-1具有明显的抑制丙烯酰胺生成的效果,并显示出非线性浓度效应,在添加量为0.1 mg/m L时达到最大抑制率,为(51.22?3.15)%;在食品体系中,PSPs-1的浓度及浸渍薯条时间皆对丙烯酰胺的产生有明显抑制效果,并显示一定的量效关系,PSPs-1浓度为0.1 mg/m L达到最大抑制率,为(51.03?2.97)%,且当浸渍时间为90 s时抑制效果最好(50.79±1.86)%。PSPs-1经RP-HPLC-ESI-MS/MS分析和与对照品比较,其可能是由含有儿茶素和表儿茶素的黄烷醇多酚组成。结论由儿茶素和表儿茶素组成的PSPs-1在2种体系中具有明显抑制丙烯酰胺产生的效果。     

原花青素对Glu-Asn体系中丙烯酰胺的抑制作用研究

本文选取荔枝原花青素(LPPC)和莲房原花青素(LSPC)进行丙烯酰胺抑制作用的研究。实验发现两种原花青素的浓度-抑制率关系均呈非线性关系,当LPPC和LSPC的添加量分别0.5 mg·m L-1和0.1 mg·m L-1时,丙烯酰胺的抑制率达到最大,分别为53.01%±5.62%和76.60%±3.20%;同时也探讨了体系中抗氧化性、色度和类黑精含量与抑制率的关系。结果表明体系抗氧化性越大,丙烯酰胺的抑制率就越高;白度越大,丙烯酰胺抑制率就越大;类黑精含量越大,丙烯酰胺的抑制率反而越低。总体来说,原花青素能显著地抑制丙烯酰胺的形成。     

蛋白基体系美拉德反应在荔枝皮原花青素作用下的抑制研究

本试验分别研究了在乳清蛋白-葡萄糖和牛血清白蛋白-葡萄糖模拟生理体系中,荔枝果皮原花青素(Litchi pericarp procyanidins,LPPC)对美拉德反应和晚期糖基化终末产物(advanced glycation end products,AGEs)的抑制作用,以荧光性AGEs的强度为表征依据。结果表明,在乳清蛋白-葡萄糖模拟体系中孵育35 d时,LPPC对AGEs的抑制效果最强,达60.21±1.34%。LPPC浓度为1 mg/m L时,相对抑制率最大可达85.33±9.02%(显著高于维生素C(Vc),p0.05)。在牛血清白蛋白-葡萄糖体系中,孵育35 d后LPPC对AGEs的相对抑制率最高达70.01±1.32%,且与LPPC浓度呈现正相关。当LPPC浓度为0.5 mg/m L时,抑制率最大为95.46±10.12%(显著高于氨基胍(AG),p0.05)。不同p H值下蛋白质的稳定性研究表明,乳清蛋白在与LPPC长期孵育后,其热稳定性明显降低,再次提示了LPPC对美拉德反应的抑制作用。LPPC可作为一种天然的食品基质的AGEs抑制剂深度开发。     

黑花生衣提取物抑制油炸马铃薯体系中丙烯酰胺形成的研究

本论文研究黑花生衣提取物对油炸马铃薯体系中丙烯酰胺形成的影响。采用黑花生衣中提取出的粗提物(BPSE)、原花青素(BPSP)、花色苷(BPSA)以及BPSP分级得到的M1、M2和M3三种不同平均聚合度的原花青素,分别将6种物质添加到马铃薯粉中,油炸后,用高效液相色谱检测丙烯酰胺含量;选择最佳抑制率最大的物质进行动力学试验。结果表明,BPSE、BPSP、BPSA、M1、M2和M3对丙烯酰胺的最佳抑制浓度分别为0.1μg/mL、1μg/mL、0.1μg/mL、1μg/mL、0.01μg/mL和0.1μg/mL,最佳抑制率分别为39.78%、60.63%、25.18%、53.35%、49.02%和43.75%,原花青素能很好地抑制丙烯酰胺形成。通过比较BPSP试验组、空白对照组和橙皮苷阳性对照组对油炸马铃薯体系中丙烯酰胺的形成动力学过程,得出丙烯酰胺在200 s时,生成量最高,BPSP可以有效抑制丙烯酰胺的形成过程。     

黑果腺肋花楸原花青素的纯化及表儿茶素和原花青素B_2含量测定

本文研究AB-8型大孔树脂对黑果腺肋花楸原花青素粗提物的吸附和解吸特性,并利用高效液相色谱法测定原花青素纯化物中表儿茶素和原花青素B_2含量。结果表明,上样溶液浓度4 mg/m L,吸附流速2 BV/h,解吸液乙醇浓度为50%,得到纯化物中原花青素含量为14.29%;高效液相色谱法采用Aglient Eclipse XDB-C18色谱柱(4.6 mm×250 mm,5μm),以甲醇(A)-水(B)为流动相梯度洗脱(0~10 min,10%A-30%A;10~20 min,30%A-70%A;20~30 min,70%A-100%A),流速1 m L/min,检测波长280 nm,表儿茶素和原花青素B2质量浓度在0.025~0.2 mg/m L内呈现良好的线性关系,两种成分的加样回收率分别为105.5%和99.8%;经测定黑果腺肋花楸纯化物中表儿茶素和原花青素B_2含量分别为14.26 mg/g和22.45 mg/g。     

原花青素HPLC测定方法研究进展

原花青素存在于很多植物组织中,近年以来,一些植物来源的原花青素由于具有优异的抗氧化、抗肿瘤、提高机体免疫力等重要的生物活性得到了较系统的研究。主要就高效液相色谱法、高效液相色谱质谱法、反相高效液相色谱-质谱法等对原花青素测定的研究进展进行综述,以便更有效地对原花青素质量进行有效检测及监控。     

多酚对美拉徳反应中丙烯酰胺的抑制率研究

食品中的丙烯酰胺(AA)主要由淀粉食品原料经美拉德反应产生,具神经毒性,抑制食品中AA的形成成为研究热点。本实验以葡萄糖和天冬酰胺为底物,建立美拉德反应模拟体系,研究了6种多酚对模拟体系中AA的抑制作用,采用1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl, DPPH)、2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二盐(2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid, ABTS)和铁离子还原力(ferric reducing ability of plasma, FRAP)三种方法分析测定了模拟体系反应终产物(MRP)的抗氧化活性,计算为(±)-6-羟基-2,5,7,8-四甲基色烷-2-羧酸[(±)-6-hydroxyl-2,5,7,8-tetramethylchromance-2-carboxylic acid, Trolox]当量抗氧化活性,并利用人工神经网络(ANN)和多元线性回归(MLR)模型预测了丙烯酰胺抑制率和MRP中Trolox当量抗氧化活性变化(ΔTEAC)间的关系。结果表明,6种多酚均能不同程度的抑制模拟体系中丙烯酰胺的形成,各多酚在10~(-9) mol/L时具有最高的抑制效果。多酚对丙烯酰胺的抑制率和MRP中ΔTEAC具有良好的线性关系,ANN模型可通过分析MRP的抗氧化能力变化预测多酚对丙烯酰胺的抑制率。     

利用模拟体系探究沙棘黄酮对丙烯酰胺生成的抑制作用及其机理

本研究旨在探究沙棘黄酮对丙烯酰胺生成的抑制作用及其机理。首先利用Asn-Glu模拟体系建立沙棘黄酮抑制丙烯酰胺生成的量效关系；在此基础上，通过紫外吸收光谱、液相色谱-质谱和高效液相色谱测定美拉德反应三个阶段的产物，运用形成/消除动力学模型及机理动力学模型研究沙棘黄酮抑制丙烯酰胺生成的机理。结果表明，沙棘黄酮对抑制丙烯酰胺生成有明显的效果，最高抑制率为62.1%；通过拟合形成/消除动力学模型发现沙棘黄酮显著降低丙烯酰胺的生成速率常数a、t_cg(P<0.05)，对消除速率常数τ没有显著影响(P>0.05)，表明沙棘黄酮主要抑制丙烯酰胺的生成阶段，对丙烯酰胺的消除阶段没有影响；通过拟合机理动力学模型发现沙棘黄酮显著降低丙烯酰胺的生成速率k₂和类黑素的生成速率k₃(P<0.05)，说明沙棘黄酮主要抑制了美拉德反应的第二阶段。综上，沙棘黄酮能有效抑制中间产物向丙烯酰胺和类黑素转化，可以作为食品添加剂应用于食品加工业中。     

高压微射流处理对葡萄籽原花青素组分构成的影响

研究高压微射流处理对从葡萄籽中提取得到的原花青素中儿茶素、原花青素B2和表儿茶素含量的影响。将原花青素在不同的处理压力(100、140、180、220 MPa和260 MPa)条件下进行1~4次循环处理,采用高效液相色谱进行定量分析。结果表明:随着处理压力的增加,儿茶素、原花青素B2和表儿茶素含量随之增加;随着处理次数的增加,含量基本呈先增加后减少的趋势;与其他处理条件下的原花青素含量相比,260 MPa条件下循环处理两次,儿茶素(0.163 2 mg/m L)、表儿茶素的质量浓度(0.128 6 mg/m L)最高;260 MPa条件下循环3次获得的原花青素B2质量浓度(0.057 6 mg/m L)最高。说明高压微射流处理会破坏高聚原花青素分子链之间的非共价键,使其解聚生成活性更高的单体、低聚体。     

牛磺酸对富含淀粉食品中丙烯酰胺的抑制作用

运用天冬酰胺/葡萄糖模式反应体系研究了牛磺酸对富含淀粉的食品中丙烯酰胺生成的影响及其抑制机理。试验结果显示:牛磺酸能够显著抑制天冬酰胺/葡萄糖反应体系中丙烯酰胺的生成,且抑制率与浓度呈剂量关系。运用LC-QTOF分析得到2种主要的反应产物:丙烯酰胺-牛磺酸加合物和丙烯酰胺二聚体-牛磺酸加合物。此外,牛磺酸与葡萄糖共存于同一体系中加热时,葡萄糖的含量显著下降,说明牛磺酸可与葡萄糖发生反应。通过模式反应体系证明:牛磺酸能够显著降低富含淀粉食品中的丙烯酰胺含量;抑制机理主要是牛磺酸与丙烯酰胺直接发生反应,反应产物为丙烯酰胺-牛磺酸加合物和丙烯酰胺二聚体-牛磺酸加合物,从而除去体系中已经生成的丙烯酰胺。此外,牛磺酸能够与葡萄糖发生美拉德反应,从而与天冬酰胺竞争消耗体系中的葡萄糖,减少了食品中的丙烯酰胺含量。     

Amino phospholipids and lecithins as mitigating agents for acrylamide in asparagine/glucose and asparagine/2,4-decadienal model systems

The role of amino phospholipids and lecithins for mitigating acrylamide formation in asparagine/glucose and asparagine/2,4-decadienal model systems was analysed in order to explore the possibility of the use of these common additives in decreasing acrylamide content in heated foodstuffs. Dipalmitoylphosphatidylethanolamine (PE), but not dipalmitoylphosphatidylcholine (PC), decreased the acrylamide determined in both model systems. In addition, the protective effect depended on the concentration of the amino phospholipid and was higher in the asparagine/glucose system than in the asparagine/2,4-decadienal system. In fact, the protection offered by PE was similar to that of glycine, therefore suggesting that both compounds had similar protective mechanisms, more likely as a consequence of the presence of a nucleophilic primary amino group in their molecules. However, ethanolamine was more protective than PE in the asparagine/glucose system and less protective than PE in the asparagine/2,4-decadienal system, which might be related to the different hydrophilic nature of both compounds. Analogously to PE, soybean and egg lecithin also mitigated acrylamide formation, mainly in the asparagine/glucose system. All these results point to lecithins as potential acrylamide mitigating additives in the formulation of food products. They may also be used in combination with amino acids and proteins.     

Lactic Acid Fermentation Reduces Acrylamide Formation and Other Maillard Reactions in French Fries

ABSTRACT Blanched and nonblanched potato rods (var. Beate) were fermented with Lactobacillus plantarum strain NC8 (10⁹ colony‐forming units [CFU]/mL) at 37 °C for 45 and 120 min. Potato rods were pre‐fried at 170 °C for 3 min, cooled, and subsequently deep‐fried for 2 min 15 s. Potato juice (var. Beate) was fermented with the same strain (108 CFU/mL) at 30 °C for 1 to 5 h. Lactic acid fermentation of nonblanched potato rods for 45 min reduced acrylamide level in French fries with 48%, and with 71% after 120 min. By blanching potato rods before fermentation, reductions in acrylamide after 45 min and 120 min were 79% and 94%, respectively. Blanching, and especially fermentation, reduced visually judged browning of the French fries. Fermentation of potato juice reduced pH from 5.70 to 4.05 after 3 h. Simultaneously, glucose declined from 610.8 mg/100 mL to 7.9 mg/100 mL, fructose from 457.8 mg/100 mL to 0.0 mg/100 mL, and sucrose from 132.0 mg/100 mL to 29.2 mg/100 mL. Asparagine content remained largely unaffected between 0 h (1217.5 μmol/100 mL) and 4 h (1175.6 μmol/100 mL) and increased slightly (1470.3 μmol/100 mL) after 5 h fermentation. Levels of several other amino acids involved in Maillard reactions, that is, alanine, arginine, phenylalanine, and serine, decreased during fermentation. It is concluded that acrylamide formation during production of French fries can be effectively lowered by lactic acid fermentation of potato rods before deep‐frying. The reduction is due to reduced levels of reducing sugars rather than reduction of available asparagine.     

Effect of Raw Potato Composition on Acrylamide Formation in Potato Chips

ABSTRACT: Recent studies have shown that subjecting foods to high temperatures during cooking processes such as frying gives rise to the formation of acrylamide. Several factors including product composition and processing conditions affect the rate of formation of this chemical in starch-rich foods. Low reducing sugar and the amino acid asparagine content is desired when cooking because the formation of acrylamide is attributed to the Maillard reaction that occurs between these food components. The cultivar 'Atlantic' was used to determine the effect of potato components (reducing sugars and asparagine) on acrylamide content during frying in a traditional fryer. A model system was developed by infusing leached potato slices with predetermined amounts of glucose and asparagine. Increasing glucose and asparagine content in the slices increased the acrylamide content in the potato chips. Color could not be used as an indication of acrylamide content because potato chips with similar color had very different acrylamide concentrations.     

氨基酸对葡萄糖-天冬酰胺模拟体系中丙烯酰胺形成的抑制作用研究

目的 研究4种氨基酸对已建立的葡萄糖-天冬酰胺模拟体系中丙烯酰胺生成的影响。方法 以葡萄糖-天冬酰胺组为对照组,在此基础上分别加入半胱氨酸、甘氨酸、赖氨酸和谷氨酸4种氨基酸为实验组,于140℃反应5～30min,测定反应后模拟体系的褐变程度、色差值、生成丙烯酰胺含量和剩余葡萄糖含量。结果 4种氨基酸中,半胱氨酸和谷氨酸对模拟体系中的褐变度和色差值的抑制作用较好;半胱氨酸和赖氨酸对底物葡萄糖的消耗作用较快;半胱氨酸对丙烯酰胺的抑制效果最好,抑制率为(76.00±0.73)%,其他氨基酸的抑制率分别为甘氨酸(38.39±0.44)%、赖氨酸(51.03±3.09)%和谷氨酸(28.76±2.43)%;进一步研究发现,当添加4.2mmol半胱氨酸时,丙烯酰胺抑制率达(95.32±0.47)%。结论 4种氨基酸相比,半胱氨酸对丙烯酰胺形成的抑制效果最好,且对于降低葡萄糖-天冬酰胺模拟体系的褐变度、色差值、葡萄糖含量有较好的效果。     

Inhibition of acrylamide formation by vitamins in model reactions and fried potato strips

The capacities of 15 vitamins in reducing the formation of acrylamide were examined. Inhibitory activities of the water-soluble vitamins were tested in both chemical models containing acrylamide precursors (asparagines and glucose) and a food model system (fried snack products), while activities of fat-soluble vitamins were examined only in the latter model. Biotin, pyridoxine, pyridoxamine, and l-ascorbic acid exerted a potent inhibitory effect (>50%) on acrylamide formation in the chemical model system. Using the food model, it was shown that water-soluble vitamins are good inhibitors of acrylamide formation. On the other hand, only weak inhibitory effects were observed with fat-soluble vitamins. Effects of pyridoxal, nicotinic acid, and l-ascorbic acid were further examined using fried potato strips. Nicotinic acid and pyridoxal inhibited acrylamide formation in fried potato strips by 51% and 34%, respectively. Thus, certain vitamins at reasonable concentrations can inhibit the formation of acrylamide.     

Characterization of Date (Deglet Nour) Seed Free and Bound Polyphenols by High‐Performance Liquid Chromatography‐Mass Spectrometry

Date (Pheonix dactylifera L.) seeds are a valuable and abundant by‐product with various potential food applications. Free polyphenols (FPPs) and bound polyphenols (BPPs) of date seeds from Deglet Nour variety grown in Australia were investigated using high‐performance liquid chromatography‐mass spectrometry. The FPP fraction contained the following main phenolic compounds per gram of date seed powder; procyanidin B1 (499.8 ± 7.8 μg), procyanidin B2 (288.6 ± 6.1 μg), catechin (167.6 ± 2.1 μg), epicatechin (39.44 ± 0.39 μg), and protocatechuic acid (1.77 ± 0.22 μg). Additionally, one of the 2 A‐type dimers was confirmed as procyanidin A2 (24.05 ± 0.12 μg/g). A‐type dimers have not been reported before in date seeds. The BPP fraction contained epicatechin (52.59 ± 0.76 μg/g) and procyanidin B2 (294.2 ± 3.7 μg/g), while several peaks exhibiting ESI^? m/z of 153 indicated dihydroxybenzoic acid isomers including protocatechuic acid (2.138 ± 0.025 μg/g). These findings contributed to our knowledge of date seed phytochemicals and understanding of their contribution to the reported bioactivities.     

Dietary plant materials reduce acrylamide formation in cookie and starch-based model systems

BACKGROUND: Dietary plant materials have attracted much attention because of their health benefits to humans. Acrylamide is found in various heated carbohydrate‐rich foods. Our previous results showed that crude aqueous extracts from diverse dietary plants and some phenolic compounds could mitigate acrylamide formation in an asparagine–glucose model system. Based on our previous study, several plant materials were selected to further investigate their inhibitory effects on acrylamide formation in cookies and starch‐based model systems. RESULTS: Addition of raw powders from selected dietary plants and their crude aqueous extracts could considerably reduce acrylamide formation in both cookie and potato starch‐based models. Aqueous extracts of clove at 4% caused the largest reduction (50.9%) of acrylamide in cookies, whereas addition of 2% proanthocyanidins from grape seeds gave the greatest acrylamide reduction (62.2%) in a starch‐based model system. CONCLUSION: It may be feasible to use some of the tested dietary plant materials to reduce acrylamide formation in cookies and other starchy foods. Copyright © 2011 Society of Chemical Industry