藜麦多肽的制备及其抗氧化活性研究

目的 优选复合酶协同超声辅助法提取藜麦蛋白的工艺以及探讨藜麦多肽的抗氧化活性。方法 采用 Box-Behnken 响应面法,对超声辅助糖化酶-纤维素酶复合酶法进行优化。使用碱性蛋白酶、菠萝蛋白酶、风味蛋白酶、木瓜蛋白酶、酸性蛋白酶、胰蛋白酶和胃蛋白酶制备藜麦多肽,通过 DPPH 法和 ABTS 法对其抗氧化活性进行探究。结果 根据响应面模型对复合酶超声辅助提取条件进行优化, 得到最佳提取条件：总加酶量 400 U/g、pH 5.0、时间 60 min。以最佳优化条件提取,藜麦抗氧化肽的 DPPH 自由基清除率最高达到 79.64%;ABTS 自由基清除率最高达到 76.14% 。结论 采用响应面法建 立的模型相对准确,藜麦蛋白的提取工艺优化方法可行;藜麦蛋白木瓜蛋白酶水解物具有较好的抗氧化活性,为藜麦作为功能食品深入开发提供依据。     

藜麦麸皮营养成分测定及其油脂的抗氧化活性研究

为了加强藜麦麸皮的利用价值,以国标、高效液相法及气质联用法测定藜麦麸皮各营养成分,并且对麸皮的脂类进行抗氧化活性测定。结果表明,藜麦麸皮中蛋白质、淀粉、油脂含量较高,分别占26.86%、28.78%、14.15%;矿物质含量也非常丰富,其中含量较高的矿物质分别为钾、镁、钙、铁,含量分别为9197 mg/kg、7145 mg/kg、651 mg/kg、120 mg/kg;6种皂苷含量为457.61mg/g。经测定,藜麦麸皮油脂主要由22种脂肪酸组成,其中相对含量较高的四种脂肪酸为反油酸、花生四烯酸、芥酸以及油酸;油脂的抗氧化活性实验表明,藜麦麸皮油脂具备一定的抗氧化活性,当浓度为100μg/mL时,对DPPH自由基以及超氧阴离子的清除率分别为9.26%、4.06%。藜麦麸皮富含各类营养物质及活性物质,具有一定的开发利用价值。     

藜麦麸皮不同极性部位的抑菌及酪氨酸酶抑制活性研究

以抑菌圈大小及对酪氨酸酶活性的抑制率为指标,筛选出藜麦麸皮中具有抑菌活性以及抑制酪氨酸酶活性的极性部位。采用75%的乙醇对藜麦麸皮进行超声提取,三种不同极性溶剂石油醚、乙酸乙酯、正丁醇进行萃取,获取四个极性部位。纸片法观察不同的极性部位对于四种致病菌的体外抑制效果,同时探究对酪氨酸酶活性的抑制效果,利用液质推断其有效成分并用高效液相对高活性成分进行定量分析。结果表明:正丁醇萃取层的活性最高,且对革兰阳性菌较为敏感但对革兰阴性菌无明显效果。对金黄色葡萄球菌的最低抑菌浓度和最低杀菌浓度分别为1.04、2.08 mg/mL,对表皮葡萄球菌的最低抑菌浓度和最低杀菌浓度分别为0.52、1.04 mg/mL。比较可知藜麦麸皮极性部位的抑菌效果要优于某些常见的中药;在浓度为1 mg/mL时对酪氨酸酶活性的抑制率为55.86%,是同浓度V_C抑制效果的58.96%;液质推断出正丁醇层主要物质为藜麦皂苷,定量分析藜麦皂苷的纯度为62.6%。综上,藜麦麸皮不同极性部位中,正丁醇萃取层的抑菌活性以及对于酪氨酸酶活性的抑制效果较好,且主要活性物质为藜麦皂苷。     

藜麦麸皮挤出改性工艺及其理化特性研究

采用双螺杆挤出技术对藜麦麸皮膳食纤维进行改性,可增加藜麦麸皮中可溶性膳食纤维(soluble dietary fibre,SDF)含量.利用单因素和响应面法优化挤出工艺参数.结果表明:在挤出温度112℃、物料粒度112 μm、物料含水量19％、螺杆转速19 Hz的条件下,改性藜麦麸皮SDF得率为37.84％,是原藜麦麸...     

藜麦芽多肽制备及其应用研究

该研究以白藜麦为原料,通过人工调控藜麦萌芽的培养条件,促进藜麦萌发过程中蛋白质向多肽的转变,制备富含多肽的藜麦芽(多肽藜麦芽)。考察浸泡温度、浸泡时间、培养时间3个因素对藜麦芽中多肽富集的影响,在单因素的基础上采用正交试验方法对藜麦芽培养条件进行优化,得出最佳培养条件为浸泡温度25℃,浸泡时间4 h,培养时间48 h,在此条件下,藜麦芽中多肽含量为(12.4±1.13)mg/g。将培养得到的多肽藜麦芽进行低温打浆处理,以冷冻干燥技术得到多肽藜麦芽粉,所得多肽藜麦芽粉呈乳白色,易溶解,在饮料等食品当中可作为营养型添加剂加入使用。     

不同酶对藜麦蛋白肽制备的影响及其抗氧化活性研究

本实验以藜麦蛋白为原料,采用碱性蛋白酶、复合蛋白酶、风味蛋白酶、木瓜蛋白酶、中性蛋白酶分别对藜麦蛋白进行水解,制备藜麦蛋白肽。通过单因素实验对五种酶水解制备的藜麦蛋白肽以蛋白水解度、DPPH自由基清除能力、·OH自由基清除能力、ABTS+自由基清除能力、·O2-自由基清除能力为测定指标,研究五种蛋白酶对藜麦蛋白的水解能力和抗氧化活性影响,选出效果相对较佳的酶水解工艺。综合各指标的结果表明,碱性蛋白酶和复合蛋白酶水解能力较强,制备的藜麦蛋白肽抗氧化活性较其他两种酶更好。碱性蛋白酶和复合蛋白酶最佳酶解工艺分别为:酶与底物比0.5%(w/w),底物与水为1∶25(w/v),水解温度50℃,水解时间5h,pH10.0;酶与底物比0.5%(w/w),底物与水为1∶25(w/v),水解温度55℃,水解时间5h,pH8.0。本研究为藜麦蛋白的后期的深加工利用提供一定理论依据。     

超声辅助离子液体提取藜麦麸皮总皂苷及其抑菌活性研究

采用超声波辅助离子液体(IL-UAE)提取藜麦麸皮中的总皂苷.考察了一系列阳离子组成不同的1-烷基-3-甲基咪唑离子液体的提取得率,并通过单因素与响应面实验探究料液比、离子液体浓度和提取时间及其交互作用对藜麦皂苷得率的影响,对IL-UAE的超声参数进行了优化.结果表明:超声辅助离子液体提取法提取藜麦麸皮总皂苷的最佳工艺...     

响应面法优化藜麦麸皮皂苷酸水解工艺

为了提高藜麦麸皮皂苷的抗氧化性,以DPPH·清除率为指标,对其酸水解工艺条件进行了响应面法优化。结果表明:影响藜麦麸皮皂苷酸水解的因素大小顺序为:水解时间水解温度盐酸浓度液液比,优化的最佳工艺条件为:盐酸浓度4.8 mol/L、液液比1∶2(mL/mL)、水解温度80℃、水解时间2.5 h。此工艺条件下,藜麦麸皮皂苷水解产物对DPPH·的清除率为68.84%,较水解前清除率提高了2倍多。酸水解可有效提高藜麦麸皮皂苷清除自由基及抗氧化活性。     

藜麦麸皮不可溶性膳食纤维对面包品质的影响

为提高藜麦麸皮利用度,改善面包品质,添加藜麦麸皮不可溶性膳食纤维（0%、3%、6%、9%）制作面包,通过对面包比容、保水性、老化性、质构特性、感官评价、抗氧化性等特性分析,研究藜麦麸皮不可溶性膳食纤维含量对面包品质的影响。结果显示：随藜麦麸皮不可溶性膳食纤维添加量增加,面包比容、弹性显著减少（P＜0.05）,保水性、硬度、咀嚼性显著增加（P＜0.05）,内聚性无显著变化,抗氧化活性显著提高（P＜0.05）。研究结果表明,添加藜麦麸皮膳食纤维可以提高面包品质。     

藜麦水解蛋白肽制备及其抗氧化活性研究

目的 使用蛋白酶水解藜麦蛋白,制备抗氧化性高的藜麦多肽。方法 通过单因素和响应面法优化,以1,1-二苯基-2-苦基肼自由基(1,1-diphenyl-2-picrylhydrazyl radical, DPPH·)清除率为指标,运用电子顺磁共振(electron paramagnetic resonance, EPR)技术,通过EPR波谱图分析,直接、准确地研究藜麦多肽的抗氧化活性。结果 根据所得EPR波谱图进行分析, 5种蛋白酶(复合蛋白酶、木瓜蛋白酶、胰蛋白酶、中性蛋白酶、碱性蛋白酶)的产物均有抗氧化性,胰蛋白酶处理所得物的DPPH·清除率最大,选择胰蛋白酶进行工艺优化,根据响应面模型对条件进行优化,得到最佳工艺条件是:酶添加量为2000 U/g、pH为7.2、温度为43.6℃、时间为4.30h。以优化所得最佳条件进行验证,藜麦抗氧化肽的DPPH·清除率为49.56%。结论 胰蛋白酶在最优条件下水解藜麦蛋白,可生产抗氧化性高的藜麦多肽。本研究为酶解藜麦蛋白生产抗氧化肽工艺提供了数据积累,有利于藜麦功能性产品的进一步研发。     

Nutritional and functional characterisation of hydrolysates from quinoa flour (Chenopodium quinoa) using two proteases

The objective was to study the nutritional and functional properties of hydrolysates from quinoa (Chenopodium quinoa) obtained by enzymatic hydrolysis of defatted quinoa flour (DQF). The commercial enzymes alcalase and flavourzyme were used to obtain the hydrolysates defatted quinoa flour hydrolysate with alcalase (DQFA) and defatted quinoa flour hydrolysate with flavourzyme (DQFF), respectively, after 3 h of digestion at 50°C and pH 8. The degree of hydrolysis (47.32%), yield (31.05%) and protein recovery (88.80%) values were higher in DQFA; however, its protein content (48.34%) was lower compared to that of DQFF (55.06%). Also, DQFA had a solubility greater than 57% over a wide pH range (2–10) and good foam stability (70–90%). On the other hand, DQFF presented adequate emulsifying activity (61.30 m²/g), emulsifying stability (158.62 min) and foaming capacity (131%). Due to the high content of macro- and micronutrients and adequate emulsifying and foaming properties, DQFA and DQFF could be used as ingredients in various processed food products and protein supplements.     

Interrelationships among seed yield, total protein and amino acid composition of ten quinoa (Chenopodium quinoa) cultivars from two different agroecological regions

BACKGROUND: Quinoa is a good source of protein and can be used as a nutritional ingredient in food products. This study analyses how much growing region and/or seasonal climate might affect grain yield and nutritional quality of quinoa seeds. RESULTS: Seeds of ten quinoa cultivars from the Andean highlands (Bolivia/Argentina site) and Argentinean Northwest (Encalilla site) were analysed for seed yield, protein content and amino acid composition. Grain yields of five cultivars growing at Encalilla were higher, and four were lower, compared with data from the Bolivia/Argentina site. Protein contents ranged from 91.5 to 155.3 and from 96.2 to 154.6 g kg^?1 dry mass for Encalilla and Bolivia/Argentina seeds respectively, while essential amino acid concentrations ranged from 179.9 to 357.2 and from 233.7 to 374.5 g kg^?1 protein respectively. Significant positive correlations were found between the content of essential amino acids and protein percentage. CONCLUSION: It appears that there are clear variations in seed yield, total protein content and amino acid composition among cultivars from the two sites. Essential amino acid composition was more affected than grain yield and protein level. The study revealed that both environmental and climatic factors influence the nutritional composition of quinoa cultivars growing in different agroecological regions. Copyright © 2011 Society of Chemical Industry     

Cell wall phenolics and polysaccharides in different tissues of quinoa (Chenopodium quinoa Willd)

Quinoa (Chenopodium quinoa Willd) is an Andean pseudo-cereal, of the Chenopodiaceae family, which is currently being studied for introduction in Northern Europe as an alternative to industrial crops. The aim of this work was to verify existence in quinoa of the distinctive cell wall features identified in other Chenopodiaceae, ie presence of pectin-bound ferulic acid and dehydrodiferulic acids. Alcohol-insoluble solids (AIS) were prepared from leaves, stems and roots of mature quinoa plants, representing 0.10, 0.20 and 0.47 g g⁻¹ respectively of the fresh weight. Ferulic acid and dehydrodiferulic acid derivatives were present in all the organs, with the highest concentrations in the leaves with 2.1 and 0.5 mg g⁻¹ AIS respectively. The ratio of dehydrodiferulic acid to ferulic acid was highest in the roots. Pectins extracted by hot HCl from AIS of leaves were rich in ferulic acid (3.4 mg g⁻¹), but also highly acetylated (DAc 20), and rich in rhamnose, two characteristics encountered in other Chenopodiaceae. © 1999 Society of Chemical Industry     

Innovations in Health Value and Functional Food Development of Quinoa (Chenopodium quinoa Willd.)

Quinoa (Chenopodium quinoa Willd., Amaranthaceae) is a grain‐like, stress‐tolerant food crop that has provided subsistence, nutrition, and medicine for Andean indigenous cultures for thousands of years. Quinoa contains a high content of health‐beneficial phytochemicals, including amino acids, fiber, polyunsaturated fatty acids, vitamins, minerals, saponins, phytosterols, phytoecdysteroids, phenolics, betalains, and glycine betaine. Over the past 2 decades, numerous food and nutraceutical products and processes have been developed from quinoa. Furthermore, 4 clinical studies have demonstrated that quinoa supplementation exerts significant, positive effects on metabolic, cardiovascular, and gastrointestinal health in humans. However, vast challenges and opportunities remain within the scientific, agricultural, and development sectors to optimize quinoa's role in the promotion of global human health and nutrition.     

藜麦皂苷研究进展

藜麦(Chenopodium quinoa Willd.)是南美洲特有的一种植物,其叶片、花、果实、籽实和种皮中富含皂苷,藜麦皂苷是一种苦味物质和抗营养因子。目前常用的皂苷提取方法主要有溶剂提取法、酸碱水解法、沉淀法、超临界CO_2法及超声波萃取法等。近年来的研究表明,藜麦皂苷具有抗氧化、抗肿瘤、抑菌、免疫调节等药理活性,这些特性都使藜麦皂苷成为医学、保健品、食品等行业的重点研究对象。本文主要对藜麦皂苷的研究现状、结构组成、提取方法、分离纯化、分析测定、生物活性、以及环境对藜麦皂苷的影响进行了概述,以期为藜麦的进一步研究开发提供参考。     

藜麦皂苷的提取及其酪氨酸酶抑制活性

探究藜麦"陇藜1号"籽粒中皂苷的最佳提取条件并验证其酪氨酸酶抑制活性。设计三因素三水平正交实验,探索料液比,乙醇浓度及超声时间对藜麦皂苷提取得率的影响。构建L-多巴诱导的B16细胞模型,测定藜麦皂苷对细胞活性及酪氨酸酶活性的影响,最终通过免疫印迹法(Westernblot)探索藜麦皂苷影响酪氨酸酶活性的作用通路。结果显示:藜麦皂苷最佳提取条件为料液比1:40,70%浓度的乙醇下超声60 min,得率为17.85 mg/g。当藜麦皂苷的浓度低于200μg/m L时,其对B16细胞无显著抑制作用,但能显著抑制酪氨酸酶的活性和黑色素的形成,200μg/m L藜麦皂苷处理B16细胞72 h,黑色素相对含量降至73.85%,酪氨酸酶活性降至53.31%。藜麦皂苷通过抑制小眼畸型相关转录因子(MITF)及酪氨酸酶(TYR)蛋白表达来抑制黑色素形成。藜麦皂苷可以作为一种具有美白活性的组分在化妆品或药品中应用。     

Afrosimetric estimation of threshold saponin concentration for bitterness in quinoa (Chenopodium quinoa Willd)

Taste testings and saponin estimation by a simple afrosimetric method showed that quinoa containing 0·11% saponins or less (corresponding to foam heights of 1·0 cm or less) can be considered sweet. A variation of the standard afrosimetric method is described which reduces total analysis time from 73 to 7 min. Used with the proper precautions, this rapid method, in which quinoa producing foam heights of 1·3 cm or less is considered sweet, is suitable for selecting promising low-saponin varieties in field trials and for monitoring the efficacy of abrasive dehulling (polishing) as a debittering process.     

响应面优化碱性蛋白酶法提取藜麦淀粉工艺

采用青海高原藜麦作为原料,碱性蛋白酶作为酶解剂,研究藜麦淀粉的提取工艺。在单因素试验的基础上,以藜麦淀粉提取率作为评价指标,利用响应面法优化提取藜麦淀粉的工艺条件。结果表明:最佳工艺条件为酶添加量为0.598%,pH值为9.09,酶解时间为122 min,酶解温度为40.60℃,在此条件下藜麦淀粉提取率的预测值为89.26%。以最佳工艺条件对藜麦淀粉进行提取,验证试验中藜麦淀粉的提取率为(89.09±0.15)%,蛋白质残留率为(1.02±0.46)%。藜麦淀粉提取率的预测值与实测值的相对误差为0.19%,与所建立的模型预测值接近,表明此模型优化藜麦淀粉提取工艺具有可行性与科学性。