低剂量X射线系统动力学机理分析及对大麦发芽的影响

建立了X射线强度与大麦种子发芽关系的系统动力学模型,阐释并确证了X射线对发芽大麦的影响和变化机理。研究发现,X射线对大麦种子发芽阶段的芽长、根长、生物量产生抑制作用,接受剂量为1 059.65 μSv/s,试验组Ⅰ在3 d后淀粉、蛋白质和脂肪含量分别比对照组延迟增加了19.8%,31.6%,33.3%,可溶性膳食纤维降低了41.8%,且变化程度与X射线强度呈正相关,但X射线对发芽率没有显著影响。     

大麦萌发过程的温度效应与相关因素分析

制麦过程是人工控制的大麦种子发芽生理反应的一个阶段。在这一阶段中,大麦种子需要有足够的水分、适当的温度和充足的氧气条件才能正常萌发溶解。这三大要素既是大麦种子生化反应的促进因素,又可形成种子生化过程中的制约条件。正确认识三大要素对大麦种子萌发的影响,是制定制麦工艺的关键。本文将对麦芽萌发过程的温度效应及温度与其它两大因素的关系作一论述,与同行们共商榷。三大麦萌发过程的环境因素分析制麦的实质是大麦种子在一定的环境条件下生长并适时终止生长过程。在大麦萌发过程中,大麦胚乳的贮藏物质在酶的作用下溶解供胚…     

藜麦发芽过程中蛋白质与皂苷及淀粉消化特性的变化规律

发芽是改善谷物质构及其营养价值的一种高效的加工方式。本文研究了藜麦发芽过程中蛋白质与皂苷及淀粉消化特性的变化规律。结果显示,发芽显著地提高了藜麦中粗蛋白和可溶性蛋白含量,分别增加了5.38%和17.55%。随着发芽时间不断增加,藜麦总淀粉、直链淀粉及支链淀粉含量分别减少25.95%、4.86%和29.53%,而还原糖含量增加了26.60%。发芽处理显著改善了藜麦种子的淀粉消化性能。发芽前藜麦种子中快消化淀粉、慢消化淀粉及抗性淀粉的百分含量分别为38.45%、43.64%和17.90%。发芽48h后,快消化淀粉的百分含量显著地增加至53.46%,而慢消化淀粉及抗性淀粉的百分含量分别下降至40.42%和6.11%。此外,发芽后藜麦种子中总皂苷含量显著增加了16.46%。研究表明,发芽的藜麦种子含有更好的营养价值和消化性能,可以用于加工功能性食品,促进人体健康。     

萌发大麦种子内肽酶活力、醇溶蛋白及氨基酸含量变化

以两个大麦品种垦啤8号和Harrington为材料研究了大麦种子萌发过程中体内醇溶性蛋白质、游离氨基酸和内肽酶活力的变化。垦啤8号大麦种子的醇溶蛋白含量高,但其降解量比Harrington多。垦啤8号游离氨基酸增长量略高于Harrington。整个大麦种子发芽期间,国产品种内肽酶活力始终高于进口品种。以上表明,与Harrington相比,虽然国产品种垦啤8号含氮量高,但其内肽酶活力升高快,最大酶活力高,醇溶蛋白降解、转化为可输出氮的进程快,有制造优质麦芽的潜力。     

日本发现调节大麦发芽的特定基因

正据日媒报道,日本冈山大等研究组发现了调节大麦种子发芽时间的基因,该发现可应用于发芽用大麦品种的开发和防止收获前在麦穗上发芽的危害。这项研究成果5月18日发表在英科学杂志《Nature Communications》电子版上。众所周知,野生大麦为了抵抗夏季高温干燥,种子成熟之后休眠几个月再发芽。由野生大     

大麦发芽过程中蛋白质组的变化研究

通过双向电泳技术监测大麦发芽过程中水溶蛋白质组的变化,明确大麦发芽过程中蛋白质组的变化规律,为麦芽制造提供一定理论依据.以澳麦“schooner”为研究对象,提取其水溶蛋白进行双向电泳分析,结合分析软件监测大麦发芽过程中蛋白质组的变化.结果显示,本实验检测出大麦种子中大约有804种蛋白质,发芽过程中有424种蛋白质未发生变化,379种蛋白质降解消失或浓度降低,另有77种新的蛋白质产生.结果表明,进一步证实浸麦阶段主要是蛋白质的降解过程;发芽前期蛋白质的降解和合成转化较为缓和,发芽中期(48～72h)蛋白质的降解最为旺盛;发芽后期蛋白质的变化基本趋于平衡.     

不同品种大麦种子萌发过程醇溶蛋白变化

以4个品种大麦甘啤2号、甘啤3号、Gairdner和Schooner为材料研究大麦种子萌发过程中蛋白酶活力和醇溶蛋白的变化.国产品种大麦醇溶蛋白含量高于进口品种,但蛋白酶活力发芽24 h以后高于进口品种大麦.在蛋白酶的作用下,国产品种大麦醇溶蛋白降解量大于进口品种大麦,发芽结束时,国产品种大麦醇溶蛋白含量低于进口品种或与之相近.表明与两个进口品种大麦相比,两个国产品种大麦蛋白酶活力升高快,最大酶活力高,醇溶蛋白降解进程快,有制造优质麦芽的潜力.     

发芽对精白保胚米淀粉分子结构的影响

目的：研究发芽对精白保胚米淀粉分子结构的影响。方法：采用扫描电子显微镜、高效液相色谱、X射线衍射仪及傅里叶红外光谱(FT-IR)分析精白保胚发芽米淀粉颗粒的表面结构、相对分子质量分布、结晶度和特征结构的变化。结果： 精白保胚米发芽之后淀粉颗粒表面结构变化不明显,但淀粉的相对分子质量、结晶度降低;发芽后精白保胚米淀粉的红外透光率降低,O－H键、C－H键和C－O键的伸缩振动均增强。结论：发芽过程中直链淀粉和支链淀粉降解,使精白保胚米淀粉分子结构发生明显变化。     

发芽对大豆蛋白凝胶性质的影响

研究了发芽大豆蛋白质凝胶性质的变化。采用碱提酸沉法制备大豆分离蛋白(SPI),以葡萄糖酸-δ-内酯(GDL)为凝固剂制备大豆蛋白凝胶,系统研究了不同芽长大豆蛋白凝胶强度的变化。通过SDS-聚丙烯酰胺凝胶电泳(SDS-PAGE)图谱分析了发芽过程中SPI的变化及其对大豆凝胶强度的影响。结果发现:SPI中7S球蛋白的α'、α亚基和11S球蛋白的酸性亚基A3、A发芽时发生明显降解,但11S球蛋白各亚基在发芽初期变化小,利于大豆蛋白质分子之间形成网络结构使凝胶强度增强。随着发芽时间的延长,11S球蛋白也部分发生降解,凝胶强度下降。     

玉米发芽过程中碳水化合物代谢变化的研究

以苏玉24号玉米品种为试材,研究不同发芽阶段玉米的主要生理生化变化和碳水化合物组成变化。结果显示：随着发芽时间的延长,干物质含量减少,芽长和发芽率均呈现不同程度的增加,呼吸强度整体呈上升的趋势,可溶性蛋白在发芽60h达到最低,与未发芽相比降低了39.47%;淀粉酶活力逐渐增大,α-淀粉酶、β-淀粉酶和总淀粉酶活力在发芽60h时分别是未发芽玉米的4.74、16.82倍和14.41倍,在发芽108h时分别是未发芽玉米的18.33、69.77倍和59.58倍;在淀粉酶的作用下,淀粉含量总体呈下降的趋势,60h达到最小值,比未发芽玉米降低了12.62%;直链淀粉含量总体也呈下降的趋势,发芽60h后比未发芽降低了3.19%,而还原糖、可溶性糖逐渐增大,在发芽72h达到最大值,分别是未发芽玉米的4.69倍和6.88倍;同时DE值(dextrose equivalent value)先增大后减小,在发芽36h后变化显著(P＜0.05),并在发芽84h达到最大值,是未发芽玉米的13.71倍。各指标相关性表明玉米发芽过程中主要生理变化对碳水化合物的组成有很大影响。     

脉冲电场对啤酒大麦萌发性质的影响

在啤酒麦芽制备过程中引入脉冲电场(PEF)技术,对浸渍后的大麦种子进行不同电场强度的处理,以了解PEF对大麦萌发性质的影响。结果表明,PEF处理有利于提高大麦萌发活力和相关理化性质。大麦籽粒经电场强度1.5、3.0、4.5、6.0、7.5 kV/cm处理后,萌发大麦的芽长、根长、根数、鲜重、干重、发芽势、发芽率、简化活力指数、还原糖含量、β-葡聚糖酶活力、α-淀粉酶活力、β-淀粉酶活力、可溶性蛋白质和氨基态氮含量等指标与对照组比较均有明显提高,发芽势、根长、β-葡聚糖酶活力、α-淀粉酶活力和β-淀粉酶活力提高的幅度分别为38.96%、43.33%、21.46%、26.48%和23.57%。对14项指标进行主成分分析的结果表明,当电场强度为6.0 kV/cm时,脉冲电场对大麦萌发的促进效果最好。     

发芽对青稞的营养成分和抗氧化活性的影响

本实验通过对青稞进行发芽处理,来研究发芽前后青稞基础营养成分、总酚、总黄酮以及抗氧化活性的变化,并以此来评价发芽对青稞的营养价值和抗氧化活性的影响。研究结果表明,发芽使青稞的蛋白质和灰分含量提高了23.4%和31.5%,使直链淀粉和脂肪含量降低了13.8%和19.2%。发芽后青稞的总酚和总黄酮含量显著提高,分别增加了85.0%和101.7%。抗氧化活性分析表明,发芽青稞的IC₅₀DPPH值和FRAP(铁离子还原能力,ferric-reducing antioxidant power)值分别为(39.98±1.14)mg/mL和0.33~1.13 μmol V_C/g,其抗氧化能力显著高于未发芽青稞。相关性分析表明,发芽青稞较强的抗氧化能力与高的总酚和总黄酮含量显著相关(R2=0.803~0.990)。这说明发芽能够改善青稞的营养价值和功能特性,其结果为青稞的加工应用以及相关功能食品的开发提供了可靠的科学依据。     

发芽对2种青稞营养成分及抗氧化活性的影响

以隆子黑青稞和藏青2000为原料,通过测定芽长、淀粉、蛋白质、脂肪、纤维、总酚、总黄酮和抗氧化活力,探讨萌发对2种青稞营养成分及抗氧化活性的影响.结果 表明:未发芽青稞中,除淀粉含量外,隆子黑青稞的蛋白质、脂肪、纤维、总酚、总黄酮含量与抗氧化活性均大于藏青2000.发茅处理降低了青稞的淀粉、蛋白质、总酚含量和铁离子还原...     

Physicochemical changes in barley starch during malting

The objective of this work was to study the physicochemical modifications of starch during the malting of barley. The results showed that malting modifies the physicochemical properties of the starch over time by the action of barley enzymes. The gelatinisation temperature of starch increased as a function of the malting time owing to the selective enzymatic attack. The viscosity of starch decreased through malting. During germination, scanning electron microscopy showed that the enzymes degrade some starch granules which exhibited micro‐holes on the surface. X‐ray diffraction showed an apparent increase in the crystallinity during the first three days of germination, reflecting the consumption of amorphous regions. Such changes have not been previously reported. Infrared spectroscopy (1200–1500 cm^?1) showed the unfolding of carbohydrates as a result of enzymatic action. Such changes in the physicochemical properties of starch indicate that the amorphous area is consumed in the early stages of malting. © 2018 The Institute of Brewing & Distilling     

烘烤和发芽对大麦挥发性风味影响的分析研究

以发芽大麦为研究对象,采用电子鼻,电子舌与气相色谱串联质谱技术相结合分别对发芽前后大麦、烘烤发芽前后大麦进行了挥发性风味研究。结果表明烘烤发芽第一天的大麦茶风味有明显的变化,电子鼻能灵敏地检测到相较于烘烤未发芽大麦茶,烘烤发芽大麦茶在传感器PA/2、T70/2、P40/1、P10/2、P10/1、T30/1上的响应值有所增加。电子舌的苦味值、鲜味值在烘烤发芽第一天的时候最高。电子鼻主成分分析能够较好地区分烘烤发芽大麦茶和烘烤未发芽大麦茶,电子舌主成分分析显示发芽1 d大麦和未发芽大麦有部分重叠。在挥发性物质上,烘烤发芽第一天的大麦的挥发性组分醛类、酮类、酸类的相对含量有所下降,在第一天分别比未发芽下降了15.3%、0.44%、7.14%。香气组分杂环类有显著变化,相比未发芽大麦增加了46.87%,香气组分比未发芽大麦多出了8种。相较于烘烤未发芽大麦,烘烤发芽第一天大麦的风味具有明显变化。     

Effect of processing on the antioxidant properties of extracts from Mexican barley (Hordeum vulgare) cultivar

The effect of traditional cooking, roasting and germination on the antioxidant capacity of a Mexican barley cultivar is presented. Barley dried grains were processed and phenolic extracts obtained by successive extractions with hexane, aqueous acetone (70%), aqueous methanol (50%) and water. Total phenolic content was evaluated by the Folin–Ciocalteu method and the radical scavenging capacity by the DPPH method. The inhibition of LDL oxidation was also determined. Results showed that cooking and roasting barley extracts increase, the total phenolic content in comparison with control (unprocessed) barley extracts, but the germination reduces it. Germinated seeds subjected to roasting, cooking and unprocessed barley grains showed a higher antioxidant activity (IC₅₀). Traditionally cooked barley grains showed the highest inhibition of LDL oxidation. These results indicate that processing affects significantly the antioxidant capacity of barley phenolic extracts.     

萌发对青稞甜醅饮料的活性成分及其抗氧化活性的影响

目的 探究青稞籽粒萌发对所制青稞甜醅饮料的活性成分及其抗氧化活性的影响。方法 对青稞籽粒进行不同时间的萌发预处理, 再进行甜醅发酵并与纯净水、稳定剂复配制备青稞甜醅饮料, 以未萌发青稞籽粒制备的饮料为对照, 测定饮料的总酚、总黄酮含量及对2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐[2-azinlbis-(3-ethylbenzthiazoline-6-sulphonate), ABTS]、1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl, DPPH)和羟自由基的清除率。结果 不同时间萌发时间处理条件下, 青稞甜醅饮料的活性成分含量及其抗氧化活性相较于对照均有所提升, 其中总酚和总黄酮含量均在萌发第40 h时达到最高, 分别为2.69 mg/mL和1.71 mg/mL, 分别比对照 2.21和1.35 mg/mL提高了21.72%和26.67%。经萌发处理后的青稞甜醅饮料对ABTS自由基和羟自由基清除能力在萌发第48 h时清除率分别达到64.64%和76.97%, 分别比对照48.83%和67.61%提高了32.38%和13.84%, 对DPPH自由基清除能力在萌发第40 h时清除率达到最高为94.11%, 比对照86.28%提高了9.07%。结论 青稞籽粒经萌发处理后制得的青稞甜醅饮料具有良好的抗氧化能力, 为提高青稞系列产品的附加值提供参考。     

原子发射光谱法测定大麦发芽时金属离子的代谢

大麦在发芽过程中大麦内部的金属离子大麦有结合态与游离态2种存在状态。利用原子发射光谱法跟踪监测其金属离子总含量和游离态含量的变化，结果显示：在大麦发芽过程中总的离子含量一般呈现出单调的变化，而游离态的离子含量随发芽时间的不同呈现出波动变化。金属离子不同的存在状态有着不同的生理功能，通过跟踪监测离子的2种状态的含量变化，可以为研究金属离子在大麦发芽过程中的生理作用提供新的方法。     

Morphological,Physicochemical and Structural Characteristics of Oxidized Barley and Corn Starches

Barley starch was oxidized to different levels and the morphological, physicochemical and structural of the resultant oxidized barley starch were determined and compared with oxidized corn starch at the same oxidation level. The amylose content in oxidized starches decreased with increasing oxidation level, and the extent of decrease was similar for both starch types. No evidences of alteration in morphology and X‐ray diffraction pattern were noted after oxidation. The crystallinity of barley starch increased with increasing oxidation but corn starch displayed a reduced crystallinity at 5% NaOCl. The onset and peak gelatinization temperatures of oxidized starches as measured by differential scanning calorimetry showed a slight increase up to 3% NaOCl and then decreased at 5% NaOCl, whereas gelatinization enthalpy gradually decreased with increasing oxidation level. The melting temperature of retrograded oxidized starches increased with increasing oxidation. Both amylose and amylopectin were degraded during oxidation, but a higher degradation in both components as determined by high‐performance size‐exclusion chromatography (HPSEC) was noted for barley starch than for corn starch. Results of amylopectin chain‐length distribution showed that the proportions of A and B1 chains significantly increased while that of B2+ chains significantly decreased. These results suggest that differences in the structure of barley and corn starches affected their responses to oxidation. Barley starch seemed to be more susceptible to oxidation with more significant reduction in pasting temperature, viscosity, and molecular size than corn starch.     

Application of Ultrasonic Waves as a Priming Technique for Accelerating and Enhancing the Germination of Barley Seed: Optimization of Method by the Taguchi Approach

In this study the effects of different intensities and exposure time of ultrasound on barley seed have been investigated to determine the optimal conditions for accelerating germination. For optimization, the Taguchi approach was used. The germination rates and/or yield of the treated sample seed were compared with those of the untreated seed germinated under normal conditions. The seeds were treated with ultrasonic energy (input power 20–90% of 460W) and were exposed to three time periods ranging from 5 to 15 min. It was found that germination of the treated barley seed was increased about 1.042‐1.065 times compared with that of the untreated seed. The ultrasonic treatment proved to be efficient in reducing the germination period by 30–45%. It was concluded that priming of seeds with ultrasound was effective in improving water uptake and germination. The data presented in this paper suggest that the increase in final germination percentage, together with the reduced germination period in treated seeds, may be due to the action of ultrasound and that it led to an improved hydration process with concurrent shell fragmentation.