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。      

莲房原花青素的稳定性及热降解动力学研究

对莲房原花青素(LSPC)的稳定性和热降解动力学进行研究。结果表明：LSPC在低温、避光和弱酸条件下能表现出良好的稳定性;NaCl、蔗糖、葡萄糖等食品原料和防腐剂对LSPC的稳定性影响不明显;H2O2对莲房原花青素破坏作用较大,NaHSO3和VC对其有保护作用;Fe3+、Fe2+、Pb2+和Al3+对LSPC有明显的破坏作用,其他金属离子影响不大;4种不同灭菌方式对LSPC的稳定性有不同程度影响,其中巴氏灭菌的影响较小,高压蒸汽灭菌的影响最大。LSPC的热降解符合动力学一级反应,其反应活化能Ea为43.10kJ/mol,反应常数k0为1.51×105,获得LSPC降解的预测模型。经验证,模型与实测值拟合较好,表明该模型是合理的。     

莲原花青素对华夫饼AGEs的抑制及感官品质的影响

本文分析添加莲原花青素（lotus seedpod procyanidins,LSPC）对华夫饼晚期糖化终末产物（advanced glycation end products, AGEs）的抑制及感官品质的影响。以面粉、鸡蛋等为原料,添加不同浓度LSPC（0、0.5、1、2、4 mg/g）并制备华夫饼（170 ℃,20 min）,通过测量华夫饼中AGEs含量、羧甲基赖氨酸含量（Nε-（Carboxymethyl）lysine,CML）、抗氧化性等指标检测LSPC对华夫饼中AGEs的抑制作用;通过色度,质构,气质,电子鼻等方法检测LSPC对华夫饼感官品质的影响。结果表明,华夫饼中AGEs含量和CML含量随LSPC浓度的增加而显著减少（P<0.05）,总酚含量随LSPC浓度的增加而显著增加（P<0.05）;华夫饼抗氧化性能随LSPC浓度的增加而显著增加（P<0.05）;LSPC的添加也影响了华夫饼的焙烤品质,华夫饼的硬度显著下降（P<0.05）,弹性和凝聚性显著性增强（P<0.05）;华夫饼的色泽显著加深（P<0.05）;风味随莲原花青素的添加显著增加（P<0.05）。本研究表明莲原花青素对华夫饼中AGEs有抑制作用,感官品质上使华夫饼口感更绵软可口,同时本文为深入研究莲原花青素对食品热加工过程中AGEs的抑制作用及感官品质的影响提供理论支撑。     

莲房原花青素体外抗肿瘤作用研究

目的:研究莲房原花青素(LSPC)的相对分子量分布及体外抗肿瘤作用。方法:用ESI-MS分析LSPC,MTT法检测人肺癌LETP-2、胃腺癌SGC-7901、黑色素瘤A3753种细胞增殖,采用平板集落实验测定3种癌细胞集落形成。结果:LSPC的分子量范围为290.1～1154.3,是以二聚体为主的低聚原花青素;一定浓度的LSPC对3种瘤细胞均有抑制作用,当LSPC浓度为100μg/mL作用72h时对3种瘤细胞生长抑制率分别为62.6%、49.8%、77.0%;集落形成抑制率分别为77.0%、43.2%、95.3%。结论:LSPC体外对LETP-2、SGC-7901、A3753种瘤细胞有显著的抑制作用。     

莲房原花青素对小鼠S180肉瘤及其免疫功能影响的研究

目的：探讨莲房原花青素（LSPC）对S180肉瘤小鼠及免疫功能的影响。方法：采用称重方法来讨论LSPC对小鼠S180肉瘤的抑制作用；采用小鼠碳廓清单核巨噬细胞吞噬功能测定法、迟发型超敏反应及血清溶血素测定方法，研究LSPC对荷S180肉瘤小鼠免疫功能的影响；结果：LSPC可抑制小鼠S180肉瘤生长、提高免疫器官的增长指数；能显著增强荷瘤小鼠巨噬细胞的吞噬功能、DNFB所致迟发型超敏反应以及抗体生成的能力。结论：初步证明LSPC对小鼠S180肉瘤的抑制作用与其增强荷瘤小鼠免疫功能有关。     

莲房原花青素对60Co-γ射线致免疫器官损伤的防护作用

目的：研究莲房原花青素（LSPC）对^60Co-γ射线致小鼠脏器损伤的影响。方法：给小鼠连续灌胃不同剂量的LSPC15d后，接受剂量4．0Gy ^60Co-γ射线照射后，于第3d处死小鼠，测定脏器增长指数并进行形态学观察。结果：小鼠经4．0Gy ^60Co-γ一次全身辐照后，100、200mg／kg bw LSPC组能使小鼠脾脏和胸腺增长指数明显提高，且与辐射对照组间有显著性差异（分别为P〈0．01和P〈0．05）。LSPC可不同程度的保护或恢复^60Co-γ射线致小鼠的脾脏、胸腺的损伤。结论：LSPC对4．0Gy ^60Co-γ射线亚慢性辐射致免疫器官损伤有一定的保护作用。     

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。     

莲原花青素与金属离子相互作用对抗氧化的影响

采用DPPH·测试法研究莲原花青素(LSPC)与金属离子反应前、后对清除DPPH·能力的影响以及对抑制脂肪氧化和脂肪氧合酶酶活能力的影响。结果表明:LSPC与金属离子反应后清除DPPH·的能力较LSPC强。金属离子与LSPC协同作用比单独使用LSPC的抑制脂肪氧化能力强。金属离子与LSPC的配合物具有强的抗氧化能力。低浓度的金属离子与LSPC有协同抑制脂肪氧合酶酶活的能力。金属离子与LSPC反应后对脂肪氧合酶酶活的抑制能力较LSPC明显提高。     

莲房原花青素抗氧化损伤作用的研究

观察莲房原花青素（LSPC）对肝脂质过氧化损伤的作用。方法（1）体外大鼠肝匀浆温度，Fe^2 ,H2O2衣导引起肝脂质过氧化物（LPO）含量变化；（2）小鼠连续口服不同剂量LSPC7d后，一次性灌胃5％CCl4油溶液10ml/kgbw,24h后检测肝与血浆中超氧化物歧化酶（SOD）和脂质过氧化物（LPO）含量。结果：不同剂量LSPC明显抑制体外肝组织LPO产生；口服中，低剂量LSPC则能显著降低CCl4中毒小鼠体内LPO含量，提高SOD活性。结论：适量LSPC具有抗氧化损伤作用，可能具有护肝功能。     

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。     

Role of precursors on the kinetics of acrylamide formation and elimination under low moisture conditions using a multiresponse approach – Part II: Competitive reactions

The effect of addition of amino acids, other than asparagine, on the kinetics of acrylamide formation and elimination reactions was investigated under low moisture conditions using equimolar asparagine-glucose-amino acid model systems, heated at temperatures between 120 and 200 °C. To this end, glutamine and cysteine were selected. A mechanistic model was proposed, composed of the basic reactions occurring in an asparagine-glucose control system on the one hand and of extra reactions in which the additional amino acids are assumed to be involved. Using this model, multiresponse modelling was applied on the responses measured (the same as before plus the concentration of the second amino acids added). In order to test the consistency of the basic model and to elucidate the mechanism(s) by which the additional amino acids act on acrylamide formation and elimination, the kinetic parameters for the different reaction steps of the basic model were fixed to the values estimated for the control system. Addition of glutamine had a slightly increasing effect on the yield of acrylamide, resulting in a significant increased rate constant for acrylamide formation and elimination. Cysteine on the contrary, had a pronounced reducing effect (>99%) on the acrylamide yield, which can mainly be attributed to an additional acrylamide elimination reaction which is dependent on the cysteine concentration.     

Reduction of acrylamide and its kinetics by addition of antioxidant of bamboo leaves (AOB) and extract of green tea (EGT) in asparagine-glucose microwave heating system

ABSTRACT:  This study investigated the effect of antioxidant of bamboo leaves (AOB) and extract of green tea (EGT) on the formation and kinetics of acrylamide in an equimolar asparagine–glucose model system. The substrates spiked with AOB and EGT were microwave-heated at 180 °C and the acrylamide content in final reaction products was quantified by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS). The results showed that both AOB and EGT could effectively reduce the formation of acrylamide in an asparagine–glucose microwave heating model system and achieved a maximum reduction rate when the addition levels of AOB and EGT were both 10⁻⁶ mg/mL reaction solution. To describe the kinetic behavior of acrylamide, a simplified kinetic model was optimized and relative kinetic rate constants were evaluated under isothermal conditions. The results indicated that the reduction effect of AOB and EGT on the acrylamide formation may partly be ascribed to the decrease of the formation rate constant ( k _F) in both AOB and EGT-spiked systems (43.4% and 32.3% of decrease, respectively, P < 0.05). The kinetic parameter k _E, which represents the elimination rate of acrylamide in both AOB and EGT-spiked systems, was not significantly different (6.9% of increase and 10.9% of decrease, respectively, P > 0.05). The results of the kinetic study indicated that addition of AOB and EGT could significantly reduce the formation rate constant ( k _F) of acrylamide, but could not significantly affect the elimination rate constant ( k _E) of acrylamide.     

花生红衣中B型二聚体原花青素对丙烯酰胺的抑制效果

丙烯酰胺是一种公认的神经毒素和致癌物,近年来植物多酚抑制高淀粉食物热加工过程中丙烯酰胺形成的研究是食品安全领域研究工作的一个热点。为了研究低聚体原花青素对丙烯酰胺形成的抑制效果,以花生红衣原花青素(Peanut Skin Procyanidins,PSPc)混合物经过凝胶色谱分离后得到的第二个级分PSPc-2为原料,通过反相高效液相色谱-二极管阵列检测器(RP-HPLC-DAD)分析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,并通过反相高效液相色谱-质谱联用技术(RP-HPLC-ESI-MS/MS)对PSPc-2进行鉴定。结果表明:PSPc-2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浓度-抑制率关系,在化学模拟体系中,PSPc-2添加浓度为0.05 mg/m L时抑制率可达66.47±1.15%,在炸薯条食品体系中PSPc-2浸渍浓度为0.1 mg/m L时抑制率可达70.59±2.34%;PSPc-2由两种B型原花青素二聚体组成。     

Role of precursors on the kinetics of acrylamide formation and elimination under low moisture conditions using a multiresponse approach – Part I: Effect of the type of sugar

The effect of type of sugar on the kinetics of acrylamide formation and elimination reactions was investigated under low moisture conditions using equimolar asparagine–sugar model systems, heated at temperatures between 120 and 200 °C. The monosaccharides glucose and fructose and the disaccharide sucrose were selected to study this effect. A mechanistic model was used as a basis for multiresponse modelling of the different responses measured (acrylamide, glucose, fructose, sucrose, asparagine, aspartic acid and melanoidins). In spite of the higher acrylamide yield per mol initial asparagine for sucrose over fructose to glucose, the kinetic parameters estimated for acrylamide formation revealed that the type of sugar, monosaccharide or disaccharide, had only a limited effect on this reaction. The corresponding activation energy, however, was significantly lower in case the disaccharide sucrose was added. An opposite trend was observed for the acrylamide elimination rate constant, being significantly higher for the system with sucrose, whereas the temperature dependence of this rate constant remained unaffected by the type of sugar available under the reaction conditions considered.     

The kinetics of acrylamide formation/elimination in asparagine–glucose systems at different initial reactant concentrations and ratios

The effect of initial reactant concentration and ratio on the kinetics of acrylamide formation and elimination was studied using diluted asparagine–glucose model systems, heated at temperatures between 120 and 200 °C. By means of single response modelling, acrylamide concentrations measured could be modelled using a simplified kinetic model, in which acrylamide formation and elimination reactions were included. Changing the reactant concentration in equimolar systems did not affect significantly the kinetic parameters (k_Fref and E_aF) for acrylamide formation, whereas the rate constant for acrylamide elimination increased with increasing reactant concentration, in the range from 0.01 M to 0.125 M. Modifying the reactant ratio, while keeping one of the reactants at a fixed concentration (0.125 M), did not affect the estimated parameters as compared to the equimolar system. In addition, multiresponse modelling was applied on three model systems with a different initial reactant ratio. Besides acrylamide, the concentration of the reactants and fructose and the level of browning were quantified. By means of deduction, a mechanistic model was proposed which was able to model all responses simultaneously in an adequate way. It appeared that caramelisation has a predominant role in browning, however, only in the system with an excess of sugar. The corresponding kinetic parameters estimated were in some cases significantly different, but in the same order of magnitude.     

莲原花青素对含有不同饱和度脂肪酸的乳糖-赖氨酸体系中晚期糖基化终末产物的抑制作用

研究莲原花青素低聚体（lotus seedpod procyanidin oligomers,LSOPC）对含有不同饱和度脂肪酸的乳糖-赖氨酸模拟体系中晚期糖基化终末产物（advanced glycation end products,AGEs）生成的抑制作用。选择α-乳糖、L-赖氨酸和油酸/亚油酸/亚麻酸建立3 种热加工模拟体系,采用荧光分光光度法、电子鼻等技术,研究了在不同加热温度和时间、不同质量浓度LSOPC、不同脂肪酸等因素的作用下LSOPC对模拟体系中生成AGEs抑制作用的影响。加热温度和时间是LSOPC抑制AGEs生成的重要因素。在各模拟体系中,LSOPC对AGEs的抑制率均随LSOPC质量浓度增加而增加,且低温加热模式下的抑制率和抑制速率比高温加热模式下大。通过电子鼻技术的指纹图谱分析,发现低温（100 ℃）时,添加LSOPC后3 种模拟体系生成的气味物质之间无明显差异,高温（180 ℃）时,则有显著差异。LSOPC对含有不同饱和度脂肪酸的乳糖-赖氨酸模拟体系中AGEs的生成有一定的抑制作用,具有剂量依赖关系,且与加热温度和时间以及脂肪酸种类相关。     

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。     

荔枝皮原花青素与VC、VE的协同抗氧化研究

选取荔枝皮原花青素(LPPC),采用DPPH自由基清除实验与等辐射分析法(Isobologram)相结合,探讨荔枝皮原花青素、VC、VE单独和复配后的抗氧化作用,结果显示：荔枝皮原花青素、VC和VE的IC50值分别为9.98、9.21、27.96mg/L,表明荔枝皮原花青素对DPPH自由基有明显的清除作用。Isobologram分析图中荔枝皮原花青素与VC、VE复配后的效应点都在相加线及95%可信限的下方,理论IC50add值与实验IC50mix值有显著性差异,并且相互作用指数都小于1,证实荔枝皮原花青素与VC,荔枝皮原花青素与VE之间存在协同抗氧化效应。     

阿魏酸与咖啡酸对丙烯酰胺形成及消减的影响

探讨阿魏酸与咖啡酸在美拉德模拟体系中对丙烯酰胺形成和消减的影响。结果表明:在天冬酰胺/葡萄糖模拟反应体系中,阿魏酸与咖啡酸的添加量为250 mmol/L和25mmol/L时可抑制丙烯酰胺的形成,而二者浓度低于2.5mmol/L时则促进丙烯酰胺的形成。将阿魏酸与咖啡酸分别与丙烯酰胺单独高温处理,发现2种酚酸对丙烯酰胺都具有消减效果,但效果不明显,因此判定阿魏酸与咖啡酸对美拉德模拟体系中丙烯酰胺含量的影响主要作用于丙烯酰胺的形成阶段。另外,酸性条件下,醌型酚酸比酚型酚酸对丙烯酰胺的消减作用更大,而在中性条件下,酚型酚酸的消减作用更强。