全麦酒酿关键加工工艺对淀粉的理化性质及体外消化性的影响

通过对淀粉颗粒表面结构、晶体结构、表观直链淀粉含量、热力学性质、溶解度与溶胀度、糊化性质及体外消化性的测定研究全麦酒酿关键加工工艺(煮制和发酵)对淀粉的影响。结果表明,煮制及发酵处理改变了淀粉的理化特性,使淀粉表面状态发生变化,但均未改变淀粉A-型结晶;与天然淀粉相比,煮制淀粉和发酵淀粉的直链淀粉含量、溶胀度、转型温度、凝胶化焓值、峰值黏度和最终黏度均显著降低,而凝胶化温度、溶解度显著增大。体外消化试验显示,天然淀粉经煮制和发酵处理后,快消化淀粉含量增加,抗性淀粉含量降低,具有更好的消化性能。全麦酒酿加工过程中发酵处理降低了煮制淀粉的消化性,可成为一种新型功能性健康淀粉食品。     

乳酸菌发酵降镉对大米淀粉结构和理化性质的影响

以乳酸菌发酵降镉后的大米作为研究对象,通过Osborne分级提取法分离出蛋白质后,分层提取大米白、黄淀粉。分析乳酸菌发酵降镉对大米淀粉的微观形态、结晶度、热特性、糊化特性、溶解度和膨润力的影响。结果表明,乳酸菌发酵降镉对大米白、黄淀粉的表面有轻微的损害;晶型未改变,为A型,但结晶度降低;糊化初始温度增加,吸热焓降低;随着糊化温度和峰值时间增加,崩解值减小;溶解度和膨润力均有小幅度增加。     

芭蕉芋淀粉对米粉理化性质及粉丝品质的影响

将芭蕉芋淀粉和籼米粉按照一定比例复配并制作粉丝,以复配粉的溶胀性质、热特性、糊化特性、流变学特性为理化性质测定指标,以粉丝的质构特性、蒸煮性质、感官品质为其质量评价指标,考察了芭蕉芋淀粉对米粉理化性质和粉丝品质的影响。结果表明：随着芭蕉芋淀粉添加量的增加,复配粉的直链淀粉含量、膨润力、峰值黏度、最低黏度、降落值、糊化焓、回生焓、回生度、弹性模量、黏性模量增加,而溶解度、最终黏度、回升值、糊化温度逐渐降低;米粉丝的硬度、弹性、黏附性、咀嚼性随芭蕉芋淀粉添加量的增加而增大。与纯籼米粉粉丝相比,复配粉米粉丝的筋道感和柔韧度增强,其光滑度却下降。综合考虑,添加2%～5%芭蕉芋淀粉的米粉丝品质最佳,具有很好的可接受性。     

纯种发酵对小米淀粉分子结构及老化特性的影响

利用自然发酵液中对淀粉老化特性起主要作用的菌种发酵,研究发酵对小米淀粉分子结构及老化特性的影响。采用0.2 g/100 m L的NaOH溶液提取发酵后的小米淀粉,研究不同菌种发酵后对小米淀粉颗粒特性、官能团、分子质量、糊化及老化特性的影响。结果表明:发酵未改变淀粉的偏光十字;植物乳杆菌、戊糖片球菌和屎肠球菌发酵后小米淀粉表面被侵蚀,酿酒酵母及芽孢菌发酵后淀粉颗粒表面侵蚀迹象变重,孔道加深且数量增多;酿酒酵母及芽孢菌发酵后小米淀粉官能团区的峰位未变,但特征峰强度减弱,植物乳杆菌、戊糖片球菌及屎肠球菌发酵后小米淀粉指纹区图谱部分消失;植物乳杆菌发酵后Ⅰ区、Ⅱ区的重均、数均分子质量较小米淀粉降低。戊糖片球菌、屎肠球菌、酿酒酵母发酵后Ⅰ区的重均分子质量升高,数均分子质量降低,Ⅱ区重均、数均分子质量降低。芽孢菌发酵后Ⅰ区的数均分子质量略有升高,Ⅱ区重均、数均分子质量降低。植物乳杆菌、戊糖片球菌及屎肠球菌发酵后淀粉的糊化温度、回生值及最终黏度降低,热焓值升高。酿酒酵母发酵后糊化温度及回生值降低,最终黏度及热焓值升高。发酵使淀粉的分子结构、支链淀粉及直链淀粉分子发生改变,短期抗老化性能提高。     

自然发酵优势菌对小米淀粉物化性质的影响

小米自然发酵过程难控制,研究自然发酵液分离并鉴定出的优势菌(乳酸菌、酵母菌)对发酵小米淀粉物化性质的影响,可更好地剖析小米自然发酵的机理,为掌握并控制自然发酵提供理论依据。采用质量浓度为0.2 g/100 mL的NaOH溶液提取发酵后小米淀粉,并测定自然发酵、乳酸菌和酵母菌发酵小米淀粉溶解度、膨润度、透明度、热特性、黏度特性。结果表明,随发酵时间的延长,3种发酵方式所得小米淀粉的溶解度、膨润度和透明度均降低,且乳酸菌和酵母菌发酵小米淀粉的透明度较自然发酵下降1.4%和1.0%;乳酸菌和酵母菌发酵96 h时糊化温度较自然发酵下降1.84℃和1.13℃,峰值温度较自然发酵下降1.04℃和0.43℃;终止温度降低3.69℃和2.85℃;热焓值较自然发酵相比上升1.00 J/g和0.78 J/g;而乳酸菌和酵母菌的衰减值、回生值较自然发酵分别下降978 mPa·s和400 mPa·s、743 mPa·s和471 mPa·s,峰值黏度较自然发酵相比上升185 mPa·s和103 mPa·s。自然发酵的优势菌(乳酸菌、酵母菌)使小米淀粉发生改性,且发酵后的物化性质较自然发酵发生显著变化。     

复配粉理化性质与米线质构性质关系的研究

将粳米粉与绿豆淀粉按照一定比例进行混合,得到粳米粉和绿豆淀粉的复配粉体系,并测定了复配粉体系的溶胀性质、糊化性质、凝胶质构性质和拉伸性质,研究了复配米粉体系的拉伸性质与米线质构性质的关系。结果表明:随着绿豆淀粉添加量比例的增加,复配米粉体系的总直链淀粉含量、可溶性直链淀粉含量和不溶性直链淀粉含量明显增加,峰值黏度、谷值黏度、末值黏度、硬度也显著性增加,咀嚼性、拉伸强度和表观弹性模量显著增加,85℃下的溶解度和膨润力显著上升;糊化温度显著降低;衰减值和回生值分别比粳米粉高了33.73 RVU和50.60 RVU;与单一体系相比,由复配粉体系制成的米线呈现较好的硬度、弹性、韧性、蒸煮性和物理性质。当绿豆淀粉∶粳米粉为1∶1时,其制得的米粉的质构性质最好。     

自然发酵对豌豆淀粉理化性质的影响

豌豆在35℃下分别自然发酵0、1、3、5 d,研究对豌豆淀粉的直链淀粉含量、透明度、溶解度、膨润力、黏度特性和质构特性等理化性质的影响。结果表明:随着发酵时间的延长,发酵液的pH从7下降到4.2,直链淀粉含量增加,透明度降低。自然发酵后豌豆淀粉的溶解度和膨润力均降低,发酵5 d后,糊化温度从73.05℃升高到83.55℃,峰值黏度从178.42 RVU降低到120.8 RVU,淀粉凝胶硬度从920.34 g降低到104.01 g。     

乳酸菌发酵对大米淀粉物理化学性质的影响

本文采用早籼稻为原料，利用乳酸菌发酵，研究发酵对大米淀粉物理化学性质的影响。对比发酵前后的大米粉，发现发酵后其保水力和溶解度以及凝胶体积膨胀率都有不同程度的增加。扫描电镜分析，发酵后大米淀粉颗粒被腐蚀，小颗粒淀粉增多。RVA和DSC结果表明：发酵后淀粉糊化过程中最高峰值粘度下降了692cp，糊化起始温度提前，糊化所需时间延长，糊化焓升高。X-射线衍射图谱显示发酵没有改变大米淀粉的晶型，但使结晶度由28％降低到22％。     

小麦粉中的淀粉对其糊化特性的影响

从小麦粉中提取淀粉、直链和支链淀粉,再将其按不同的梯度添加到原小麦粉中去,用RVA来测定其粉糊化特性,以此来研究同源小麦淀粉、直链和支链淀粉对其糊化特性的影响规律。随着淀粉或支链淀粉添加量的增加,小麦粉糊化时的峰值黏度、低谷黏度、崩解值、最终黏度、衰减值和峰值时间都出现了上升的趋势,而糊化温度则表现为降低趋势。随着直链淀粉添加量的增加,小麦粉糊化时的峰值黏度、低谷黏度、崩解值、最终黏度、衰减值、峰值时间和糊化温度都出现了下降的趋势。     

热处理对不同直链淀粉含量的玉米淀粉理化性质的影响

采用快速黏度分析法、离心法、差示扫描量热分析法、动态流变仪分析法等,研究了干热与湿热处理对3种不同直链淀粉含量的玉米淀粉糊化性质、膨润性质、热力学性质、流变性质的影响,为淀粉的物理改性研究和加工应用提供理论依据。结果表明,干热处理使淀粉更易糊化,表现为3种玉米淀粉糊化温度降低,溶解度、膨胀度增加。湿热处理加大糊化难度,使3种玉米淀粉的糊化温度升高,膨胀度降低。热处理使玉米淀粉糊稠度、糊化焓值降低。蜡质玉米淀粉经热处理后,溶解度和老化率增加。流变性质测定结果表明,湿热处理不利于高直链玉米淀粉黏弹性凝胶的形成。     

Physicochemical properties of the starchy flour extracted from sweet potato tubers through lactic acid fermentation

The efficiency of starch extraction from sweet potato tubers was improved by lactic acid fermentation using a mixed culture inoculum. Study of the properties of the starchy flour showed that there was a significant reduction in the starch content and consequently the soluble and apparent amylose contents of fermented samples from all six varieties used. A fall in peak viscosity and viscosity breakdown was observed for fermented samples, while the pasting temperature was enhanced significantly. The fermented flour showed greater solubility and reduced swelling. Differential scanning calorimetry studies indicated a delay in gelatinisation and a fall in enthalpy of gelatinisation of the starch on fermentation. Unlike cassava, all the properties of the starch from sweet potato tubers, ie viscosity, swelling, solubility, gelatinisation temperature, amylose content and starch content, were affected by fermentation, and variation was also observed among cultivars. Copyright © 2005 Society of Chemical Industry     

Physicochemical Changes in Cassava Starch and Flour Associated With Fermentation: Effect on Textural Properties

Physicochochemical changes in cassava starch and flour associated with fermentation were investigated and related to textural properties of its flour pastes. Cyanide and pH decreased, while crude protein, acidity, and apparent amylose content increased in the fermented products. Average starch granule diameter, solubility, and swelling power were depressed, while gelatinization enthalpy increased. Amylograph of starch showed increased peak visocity temperature, reduced peak, breakdown, and setback viscosities, while Texture Profile Analysis showed a decreased in hardness, cohesiveness, elasticity, and gumminess of the fermented flour paste. The altered textural properties were attributed to greater starch granule stability due to short amylose-like fragments formed by enzymatic hydrolysis of amylopectin.     

干热处理对藜麦淀粉结构和理化性质的影响

以高筋小麦粉为原料添加酵母制作面团,在温度28℃、湿度80%条件下发酵1～6 h,提取小麦淀粉。研究发酵时间对小麦直链淀粉含量、损伤淀粉含量、粒径、颗粒表面结构、糊化及消化特性的影响。结果表明：面团发酵1 h后直链淀粉含量和损伤淀粉含量均显著低于原淀粉(P<0.05)。快速黏度分析结果表明,发酵1 h的小麦淀粉峰值黏度、热浆黏度和冷浆黏度最低。发酵处理后淀粉的粒径均小于原淀粉,其中发酵5 h的平均粒径最小。扫描电镜结果表明,发酵6 h的小麦淀粉颗粒表面出现破裂现象。体外消化实验表明,发酵5 h和6 h小麦淀粉的消化速率最高,发酵后抗性淀粉含量低于原淀粉,而慢消化淀粉含量高于原淀粉(P<0.05)。     

Physicochemical properties of thermal alkaline treated pigeonpea (Cajanus cajan L.) flour

Thermal alkaline treatment, normally used for corn, was applied to pigeonpea grains. Starch granules were isolated using wet milling and alkaline treatments. Effects of the calcium hydroxide [Ca(OH)₂] concentration in the range of 0–1% (w/v) on granule structure, crystalline structure, chemical composition, and physicochemical, thermal, and pasting properties of isolated starch granules were determined. Compared to native samples, thermal alkaline treated samples had higher protein, lipid, calcium, and phosphorus contents, but lower starch and amylose contents. Thermal alkaline treatment increased starch granular size and gelatinization temperatures, but decreased relative crystallinity, gelatinization enthalpy, swelling power, solubility, amylose leaching, and the pasting viscosity. Amylose-lipid complexes were not found in thermal alkaline treated flours. As the Ca(OH)₂ concentration increased, the amylose content, relative crystallinity, gelatinization temperature, and enthalpy also increased, but the swelling power, solubility, amylose leaching, and paste viscosity decreased. A higher Ca(OH)₂ concentration produced more stable starch granules that resisted re-gelatinization.     

乳酸湿热处理改善大米粉性质及粉条品质的研究

主要研究乳酸湿热处理对大米粉性质及其干粉条和湿粉条品质的影响。以水磨籼米粉为原料,通过不同浓度乳酸、湿热以及乳酸与湿热联用的方法对米粉进行处理,研究不同条件下制备的大米粉的糊化特性、溶解度、膨胀率以及干粉条和湿粉条的蒸煮品质和质构品质。实验结果表明:乳酸湿热处理对大米粉糊化特性影响显著,大米粉通过湿热处理、乳酸处理、乳酸湿热联用处理后,大米粉的峰值黏度、谷值黏度、衰减值、最终黏度、回生值都有所降低。在乳酸处理(pH=4)时,峰值黏度最高。乳酸湿热处理对大米粉的溶解度和膨胀度都有一定的影响,与原样相比,被处理过的样品其溶解度、膨胀度都逐渐降低。在粉条蒸煮品质测定中,乳酸处理(pH=4)后,干粉条和湿粉条的断条率、蒸煮损失率都达到最低。在粉条质构品质测定中,经过湿热处理、乳酸处理和乳酸湿热联用处理三种方法处理以后,湿粉条的硬度、咀嚼性均有所下降,在乳酸处理(pH=4)时,湿粉条的弹性达到最大;在湿热处理、乳酸处理和乳酸湿热联用处理中,干粉条的黏度有所下降,在乳酸(pH=4)时,干粉条的弹性达到最大。最终结果:在乳酸处理(pH=4)时,对改善大米粉性质及粉条品质的效果是最优的。     

植物乳杆菌发酵对燕麦蛋白溶解度和营养特性的影响

利用植物乳杆菌(Lactobacillus plantarum)发酵燕麦酸面团,测定发酵过程中面团酸度和菌落总数的变化以显示菌体在体系中的生长情况,并着重研究乳酸菌发酵对燕麦蛋白的溶解度和体外消化率、氨基酸组成和营养指标的影响。结果表明：植物乳杆菌在燕麦基质中生长良好,具有较强的产酸能力;植物乳杆菌发酵可以显著(P＜0.05)提高燕麦蛋白的溶解度,发酵24h和48h的样品与未发酵样品相比,分别提高了19.50%和54.06%。采用胃蛋白酶和胰蛋白酶两步法分析发酵过程中燕麦蛋白体外消化率的变化,发现植物乳杆菌发酵可以显著(P＜0.05)提高燕麦蛋白的体外消化率。植物乳杆菌发酵对燕麦蛋白的总氨基酸含量及组成无显著影响,但其氨基酸评分(AAS)由原来的71.53提高到76.60,蛋白质功效比值(PER)也有所增加。     

脱脂对燕麦淀粉理化性质影响研究

研究了燕麦粉的脱脂条件和脱脂对燕麦淀粉性质的影响.结果表明:燕麦粉脱脂条件为料液比为1∶4,脱脂时间4h;燕麦淀粉经脱脂后粗脂肪和损伤淀粉含量分别降低81.3％、26.9％;燕麦破损淀粉含量由4.64％下降至3.63％;燕麦淀粉经脱脂透光率增加、沉降体积变小、冻融吸水率下降;经脱脂后燕麦淀粉溶解度下降,膨润力变高;经脱脂燕麦淀粉峰值黏度升高,谷值黏度基本不变,衰减值、最终黏度、回生值、糊化温度均有所下降.     

Morphology and physicochemical changes in rice flour during rice paper production

Rice flour samples from four steps of rice paper processing were prepared from rice grain, Chainart 1 variety: wet-milled flour (WMF), 24 hour soak-milled flour (24SF), 48 hour soak-milled (48SF), and dried rice paper (DRP). Decrease in protein, fat and amylose content occurred during prolonged fermentation but increase of ash content due to addition of salt occurred. Because of lactic acid bacteria activity, increases occurred in titratable acidity as lactic acid in soaking water during fermentation. Scanning electron microscopy revealed that starch granule surfaces wilted and showed corrosion channels with longer fermentation. Pasting and thermal properties of the four samples were significantly different; 24SF and 48SF showed lower peak viscosity, breakdown and final viscosity. Increasing fermentation time increased gelatinization temperature, endothermic energy and relative crystallinity. The results suggest that lactic acid and enzyme hydrolysis during fermentation in rice paper processing caused significant decrease in amorphous structure and increase in crystallinity in rice starch.