利用双孢蘑菇蛋白酶解液制备呈味基料的研究

以双孢蘑菇蛋白酶解液为反应基液,通过美拉德反应制备呈味基料,对双孢蘑菇蛋白酶解液美拉德反应中的氨基酸和糖进行筛选,考察总糖添加量、氨基酸添加量、反应时间、反应温度和pH值对反应产物的影响,并通过正交试验对双孢蘑菇蛋白酶解液美拉德反应条件进行优化。结果表明:双孢蘑菇蛋白酶解液美拉德反应中添加谷氨酸和木糖效果最好,优化的条件为:木糖添加量7%、谷氨酸添加量5%、反应时间50 min、反应温度120℃、pH 10。经感官评定,利用双孢蘑菇蛋白酶解液美拉德反应制备的呈味基料具有食用菌特有的浓郁芳香味,并且味道鲜美适口,醇厚。     

美拉德反应修饰法制备珍珠蚌抗氧化肽

为了探索美拉德反应对珍珠蚌多肽抗氧化活性的影响,以还原力为指标,在单因素实验的基础上,应用响应面法(RSM)优化珍珠蚌抗氧化肽的美拉德反应工艺。依据回归分析确定其抗氧化活性的影响因子,得到最佳的工艺条件为:修饰反应物:木糖;反应温度:100℃;糖肽比:3∶1;pH:5.0;反应时间:40 min。在该条件下,反应后的珍珠蚌多肽的还原力、羟基自由基清除率分别是反应前的9.7倍和5.2倍,清除DPPH自由基的半数抑制浓度(IC50)为0.218 mg/mL,清除能力明显高于反应前。结果表明美拉德反应是提高珍珠蚌多肽抗氧化活性的有效方法。     

不同模式体系美拉德反应程度及抗氧化活性比较

以葡萄糖、果糖、蛋氨酸、甘氨酸、精氨酸和大豆分离蛋白为美拉德反应原料,研究加热时间和混合比例对褐变程度的影响,并对褐变程度最强的产物进行抗氧化活性检测。结果表明：葡萄糖、果糖分别与甘氨酸按物质的量之比2:1混合(pH9.0),并于100℃恒温水浴锅中加热180min时褐变程度最强。葡萄糖-甘氨酸与果糖-甘氨酸模式体系的美拉德反应物都具有一定的抗氧化能力。在相同体积分数条件下,果糖-甘氨酸模式体系的美拉德反应物的还原能力和抗氧化值均要强于葡萄糖-甘氨酸模式体系的美拉德反应物。葡萄糖-甘氨酸模式体系的美拉德反应物对 ·OH和O2 ·的抑制率最高分别达50.65%和45.42%,而果糖-甘氨酸模式体系的美拉德反应物对 ·OH和O2 ·的抑制率最高则分别达57.55%和28.54%。     

美拉德反应修饰的鲢鱼肽抗氧化活性初探

美拉德反应修饰是改善肽抗氧化活性的新途径。本实验采用鲢鱼肽与葡萄糖作为反应原料,以不同的浓度反应0,2,4,6,8,10h,并分别对棕色变化、还原糖、游离氨基、还原力和DPPH自由基清除活性进行了测定,结果表明美拉德反应产物均表现出很好的抗氧化活性,还原力在一定的范围内随时间的增加而增强,E组(10g鲢鱼肽和5g葡萄糖)最大,在10h时为A组的6.09倍。清除DPPH自由基的活性则在2h时达到较高的值,E组具有最高的的自由基清除率为64.45%。美拉德反应产物的还原力与DPPH自由基清除活性不一致,而且其抗氧化能力不完全依赖于产物的褐变程度。     

双孢蘑菇抗氧化肽的没食子酸化修饰及其体外抗氧化活性

采用没食子酸(GA)对双孢蘑菇抗氧化肽(ABAP)进行修饰,通过正交试验优化GA—ABAP的制备工艺,利用紫外—可见光谱及红外光谱证实了修饰反应的发生,同时通过体外试验模型比较ABAP修饰前后抗氧化活性变化。结果表明,GA—ABAP的最佳制备工艺为:GA与ABAP的体积比5∶1,pH 11.0,微波(起始700 W,沸腾后改为140 W)加热时间8min;该条件下制备的GA—ABAP的抗氧化活性较ABAP显著提高,还原力和对DPPH自由基的清除能力分别是修饰前的11.16和9.83倍,对Fe2+的螯合能力和对超氧阴离子自由基的清除能力分别比修饰前增加了78.00%和109.80%,说明GA修饰可有效提高ABAP的抗氧化活性。     

超声波对蛋清蛋白-果糖美拉德反应体系的影响

以蛋清蛋白-果糖体系(EW-F)为对象,研究超声波对反应体系pH、自由氨基、1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除能力、还原力和亚硝酸根离子清除能力的影响 . 结果表明:超声波能促使反应体系pH和自由氨基含量降低,促进美拉德反应进程,提高美拉德反应体系的抗氧化能力.     

还原糖种类对花生蛋白水解物制备美拉德反应产物的影响

以花生蛋白水解物(PPH)为原料与还原糖进行美拉德反应,研究了还原糖的种类(葡萄糖、半乳糖、果糖)对美拉德反应产物(MRPs)的理化特性(pH、游离氨基含量、中间产物、褐变程度以及荧光强度)和抗氧化能力(还原能力、ABTS+自由基清除能力)的影响机制.结果表明:随着反应的不断进行3种美拉德反应体系都出现游离氨基含量降低...     

美拉德反应优化藜麦多肽抗氧化活性的研究

通过美拉德反应修饰藜麦多肽，以期获得抗氧化活性更高的藜麦多肽美拉德产物(QP-MRPs)。通过单因素试验，考察了QP-MRPs对DPPH自由基(DPPH·)和羟基自由基(·OH)的清除能力。运用电子顺磁共振(electron paramagnetic resonance, EPR)波谱技术，更加直接、准确地研究QP-MRPs的抗氧化活性。结果表明，4种糖(核糖、木糖、葡萄糖、果糖)的美拉德产物均有抗氧化活性，核糖、木糖生成的QP-MRPs的DPPH·和·OH清除率较高，选择木糖进行工艺优化。运用均匀试验设计法对条件进行优化，得到最佳工艺条件：肽糖比为1.5∶1,反应pH为10,反应温度为140℃,反应时间为240 min。以优化所得到的最佳条件进行验证试验，QP-MRPs的DPPH·清除率和·OH清除率分别为76.11%和71.57%。使用木糖在最优条件下修饰藜麦多肽，可生产抗氧化活性高的QP-MRPs。     

大豆肽的制备及其美拉德反应产物特性研究

本文以高温大豆粕为原材料,模拟酱油制曲工艺,通过发酵和酶解技术制备大豆肽,研究大豆肽及其美拉德反应产物的特性。通过比较其蛋白质回收率、DPPH自由基清除率等抗氧化指标、褐变程度及其肽分子量分布情况,深入研究了发酵酶解工艺和酶解时间对大豆肽及其美拉德产物抗氧化特性的影响。研究发现,发酵和酶解处理均可显著提升高温大豆粕的蛋白质回收率和抗氧化活性,在酶解时间为24 h时大豆粕的回收率达到最大值77.21%,此时大豆粕酶解产物的DPPH自由基IC50值和还原力(A700)分别为0.77 mg/m L和0.16。而美拉德反应则可以进一步提升大豆粕酶解产物的抗氧化活性。另外美拉德反应过程中分子质量较大的组分热降解反应比较剧烈,而小分子寡肽则比大分子多肽具有更高的美拉德反应活性。     

脉冲电场对还原糖-谷氨酸钠体系美拉德反应的影响

主要研究了脉冲电场对于不同还原糖-谷氨酸钠溶液的pH、中间产物、褐变、还原糖含量以及抗氧化活性的影响。结果显示:脉冲电场处理条件为场强4kV/cm,时间1.88ms,得到果糖-甘氨酸钠体系在294nm和420nm的吸光值从0分别增加到1.71和0.07,同时,抗氧化活性增加10.96%,果糖含量减少55%。气质分析表明,经脉冲电场处理可以引发葡萄糖、蔗糖、麦芽糖和乳糖分别与谷氨酸钠体系的美拉德反应,产物包括苯的衍生物、酰胺及醛,但是在果糖-谷氨酸钠反应液中发现了丙烷、醋酸和丁内酯。研究证明,脉冲电场是一种提高还原糖-谷氨酸钠体系美拉德反应的有效方法。     

超声促进美拉德反应对金带细鲹鱼肉蛋白酶解物的修饰及潜在危害物形成的影响

本文采用超声波法促进金带细鲹鱼肉蛋白酶解物与葡萄糖间的美拉德修饰反应,研究美拉德反应对酶解物功能特性、抗氧化性及潜在危害物形成的影响。结果表明:超声功率或反应时间越高,修饰产物中游离氨基含量越低,接枝度越大,超声处理能加快美拉德反应的速率,且减少丙烯酰胺等美拉德反应潜在危害物的形成。功能特性分析表明,超声处理能显著提高酶解物的溶解性和乳化性(p0.05),同时,体外模拟消化分析表明,超声处理降低了酶解物的消化性。修饰产物的DPPH自由基清除力、羟自由基清除力、还原力和Fe~(2+)螯合力显著提高(p0.05),而且超声修饰的能力和修饰物的特性均优于水浴法处理组。超声波促进美拉德修饰反应可提高金带细鲹鱼肉蛋白酶解物的功能特性和抗氧化活性,并减少丙烯酰胺等美拉德反应潜在危害物的形成。     

Optimization of Maillard reaction products from casein-glucose using response surface methodology

Response surface methodology (RSM) was applied to optimize the processing parameters of casein-glucose Maillard reaction for improving the emulsifying ability and antioxidant activity. The effect of heating time, temperature and initial pH on Maillard reaction products (MRPs) was evaluated. Emulsifying ability and reducing power were taken as response values. An increase of temperature in range and initial pH were associated with an enhanced emulsifying ability and reducing power of the MRPs. Substrate concentration 20%, casein-glucose ratio 1:2, heating time 132.7 min, temperature 100.2 °C and initial pH 12.0 were optimum conditions for the improved emulsifying ability and antioxidant activity of the MRPs. The predicated results for optimum reaction conditions coincided well with experiments values.     

Characteristics and antioxidant activity of Maillard reaction products from psicose-lysine and fructose-lysine model systems

D-Psicose, an epimer of D-fructose isomerized at C-3 position, is a rare ketohexose that is thought to be beneficial for obese people and diabetic patients as a noncaloric sweetener. In the present study, model Maillard reaction products were obtained from D-psicose (or D-fructose) and L-lysine heating at 120 °C up to 8 h with the initial pH 9.0. The changes in pH, UV-vis absorbance, and free amino groups during the reaction were detected. Moreover, the antioxidant potential of the Maillard reaction products at different intervals was investigated. Although there was almost no difference in the oxygen radical absorbance capacity, the Maillard reaction products from psicose performed better than that from fructose in the radical-scavenging activity of 2, 2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt and 1, 1,-diphenyl-2-picryl-hydrazyl. The reducing power of the Maillard reaction products from psicose was also stronger than that from fructose. These results indicated that psicose played an effective role in the Maillard reaction and its Maillard reaction products could act as potential antioxidants in food industry.     

Characteristics and antioxidant activity of ultrafiltrated Maillard reaction products from a casein–glucose model system

Maillard reaction products (MRPs) were prepared from casein–glucose by refluxing for 130 min at 102 °C and initial pH 12.0 without pH control to investigate the characteristics of casein–glucose Maillard reaction and the antioxidant activity difference among different fractions of MRPs. Browning and intermediate products increased, however, the pH of the system decreased with increase in the heating time. Free amino group content decreased 78% during first 10 min and did not change nearly thereafter. Amino acid analysis indicated that lysine and arginine decreased significantly, and casein was partially hydrolysed to peptides or free amino acid. High molecular weight compounds were dominant in the MRPs, determined by high performance gel-filtration chromatography. After ultrafiltration, antioxidant activity of each MRPs fraction was investigated by DPPH radical-scavenging activity, reducing power, Fe²⁺ chelating activity and lecithin oxidation assay. MRPs of different molecular weight exhibited distinctly different antioxidant activities.     

Antioxidant capacity of Maillard reaction products’ fractions with different molecular weight distribution from chicken bone hydrolysate – galactose system

Maillard reaction products (MRP) were prepared from an aqueous chicken bone hydrolysate (CBPH) – galactose systems by heating at 100 °C for up to 7.5 h without pH control, and then separated into the <3‐, 3‐ to 10‐ and >10‐kDa fractions using ultrafiltration. Antioxidant capacity and spectral properties of these MRP fractions were studied. The scavenging activity towards DPPH and hydroxyl radicals as well as reducing power of each MRP fraction increased with the heating time, in accordance with the increase in UV absorbance, browning and fluorescence intensity. For the same MRP, the fraction with high molecular weight (MW) demonstrated the stronger radical scavenging activity and reducing power than that with low MW. Radical scavenging activities of MRP fractions largely depended on their MW, while their reducing powers were more related to the reaction progress. These results suggested that antioxidant capacity of MRP fractions should be positively related to its molecular size.     

Sensory Characteristics and Antioxidant Activities of Maillard Reaction Products from Soy Protein Hydrolysates with Different Molecular Weight Distribution

Soy protein was hydrolyzed using two enzymes to obtain soy protein hydrolysate (SPH), the SPH was fractionated with ultrafiltration membranes to obtain peptide fractions below 1,000 Da (SP1) and 1,000–5,000 Da (SP2), and for the meantime, SPH was further completely hydrolyzed to get compound amino acids (CAA). Maillard reaction products (MRPs) were prepared from aqueous xylose–SPH/SP1/SP2/CAA model systems by heating at 120°C for 2.0 h. Compared with the original hydrolysates and other MRPs, the MRPs from SP2 exhibited a distinctly enhanced effect on flavor, including the caramel-like, soy sauce-like odors, umami and mouthful tastes and a greatly reduced bitterness in consomme′ soup. Antioxidant activities of SPH, SP1, SP2, CAA, and their MRPs were investigated through reducing power, DPPH radical-scavenging activity, and Fe²⁺ chelating activity. Before Maillard reaction, the antioxidant activities of peptide fractions with different molecular weights were quite different, and SP2 showed the highest activity; however, CAA exhibited very poor antioxidant activity. The antioxidant activities of SPH, SP1, SP2, and CAA were greatly enhanced by Maillard reaction, and the MRPs prepared from xylose–CAA model system exhibited a higher antioxidant activity than those from other model systems. Pyrazines, pyrroles, furans, and thiazoles were significantly correlated with reducing power and Fe²⁺ chelating activity by principal component analysis.     

鲢鱼肽美拉德反应产物超滤组分的抗氧化活性研究

鲢鱼肽美拉德反应产物(MRPs)经5 k Da、1 k Da超滤膜分离、然后再经溶剂分级后,获得了不同组分,分析其抗氧化活性与理化特性。通过对不同组分的DPPH自由基清除活性、金属离子螯合活性和总抗氧化能力的测定可以看出,水溶性组分中的高分子量化合物比低分子量化合物具有较高抗氧化活性,而醇溶性组分中高分子量的抗氧化活性比低分子量的低。MRPs中水溶性组分F-3(5 k Da)对DPPH自由基清除活性、对金属离子的螯合活性和总抗氧化力最高;水溶性组分中F-3和F-2(1 k Da~5 k Da)的褐变程度较高,F-3的荧光强度最高;FI-IR分析发现,F-2和F-3在860.01 cm-1和948.61 cm-1处有强烈的吸收峰,这表明肽因美拉德反应发生了结构的变化。因此,鲢鱼肽MRPs中起主要抗氧化作用的为水溶性物质,且其中相对高分子量的有色水溶性产物抗氧化活性较强。     

大蒜/肉桂精油复配PE膜对双孢菇的保鲜研究

将大蒜精油与肉桂精油以1∶2的比例复配,分别吸取5、10、15、20μL复配精油添加到双孢菇PE膜包装袋中,根据双孢菇保鲜评价指标评价组合包装对双孢菇的保鲜效果。试验结果表明:与单独PE膜包装相比,10μL大蒜/肉桂精油复配PE膜可有效保持双孢菇的感官、Vc含量和总酚含量,降低褐变度,对还原糖含量和失重率影响不大;可将双孢菇的保鲜期延长2d。     

Effect of the Reactant Ratio on the Characteristics and Antioxidant Activities of Maillard Reaction Products in a Porcine Plasma Protein Hydrolysate-Galactose Model System

The chemical characteristics and antioxidant properties of Maillard reaction products formed in the Maillard reaction in a model system at 95°C for different lengths of time (0–6 h) were investigated at three mass ratios (1:1, 1:2, and 1:3) of porcine plasma protein hydrolysate to galactose. The results revealed that the pH value and free amino group content decreased (p < 0.05), whereas the browning index, intermediate products, and browning intensity, as well as reducing power and 2,2’-amino-di(2-ethyl-benzothiazoline sulfonic acid-6)ammonium salt radical scavenging activity of the Maillard reaction products increased as the reaction time increased (p < 0.05). Moreover, when the mass ratio of porcine plasma protein hydrolysate to galactose was 1:3, the Maillard reaction progressed easily, which rendered a higher degree of glycation and antioxidant activity (p < 0.05). These results indicated that the Maillard reaction can improve the antioxidant capacity of porcine plasma protein hydrolysate.