Effects of high pressure and temperature on the structural and rheological properties of sorghum starch

Pressure-induced gelatinisation of sorghum starch was studied and compared to heat-induced gelatinisation. Starch suspensions were treated at increasing pressure (200–600 MPa) or temperature (60–95 °C) for 10 min. The degree of gelatinisation was determined using differential scanning calorimetry, changes in birefringence and damaged starch measurements. Furthermore, the pasting behaviour and structural changes during gelatinisation were investigated using rheology and microscopy. The pressure-induced as well as the temperature-induced gelatinisation curves were sigmoid-shaped. Gelatinisation occurred between 300 MPa and 600 MPa or between 62 °C and 72 °C. No significant differences were found between the rheological properties and the microstructure of the pressure-treated samples and the temperature-treated samples within the gelatinisation intervals. Granules lost their birefringence, but granular structure was maintained; however, when heated beyond the endpoint of gelatinisation, the formation of a “sponge-like” structure was observed. This change in structure at very high temperatures was reflected by a decrease in complex viscosity.

Industrial relevance

In order to apply high pressure as an alternative to temperature in the structural engineering of starch-based systems, a full understanding of the pressure-induced gelatinisation process is necessary. No rheological and ultra-structural differences were observed between pressure- and temperature-induced gelatinisation of sorghum starch. These results indicate that pressure treatment can be utilised as a replacement technology for temperature during processing of complex starch-containing products.     

储藏温度对稻米淀粉糊化特性的影响

为研究稻谷储藏温度对稻米淀粉糊化特性的影响,用人工气候箱将早籼稻谷在5、15、25、35 C条件下储藏12个月.分析测定了不同温度储藏稻米淀粉的提取率、色泽、溶解度、润涨力、糊化特性及淀粉凝胶的质构特性.结果表明,相对于新收获稻米,经35℃储藏稻米提取的淀粉色泽微黄,淀粉提取率降低了19.65％;5℃储藏稻米淀粉在90℃时的膨润力最大,经储藏处理稻米淀粉在80℃和90℃的溶解度均高于新收获稻米;稻米淀粉的糊化温度和淀粉凝胶的硬度随储藏温度升高而增加,淀粉的峰值黏度和最终黏度及淀粉凝胶的黏聚性随储藏温度升高而降低.     

高压均质对板栗淀粉糊化、流变及质构特性的影响

研究了不同均质压力、均质次数、淀粉乳浓度对板栗淀粉糊化、流变、质构及偏光特性的影响。经20～100 MPa处理后,峰值、谷值和终值黏度较原淀粉减小2. 36%～8. 58%、4. 33%～12. 73%和2. 88%～8. 92%;增加均质次数,崩解值和糊化温度分别降低3. 03%～15. 54%和3. 90%～7. 42%;经高压均质处理后,质量分数为1%～10%淀粉乳的峰值、谷值和终值黏度下降4. 59%～8. 58%、11. 24%～12. 73%和7. 35%～8. 22%。同时,高压均质处理后淀粉糊稠度系数减小,储能模量和损耗模量显著降低,硬度、黏性、弹性等凝胶特性显著改变,且淀粉偏光十字模糊,结晶区被破坏。高压、少次、高浓度条件下的均质改性效果最佳,所得的淀粉黏度低、黏弹性减小、抗剪切稀化且凝胶强度低,可显著改善板栗乳饮料、板栗营养粉等产品的稳定性、口感与消化性。     

醋酸酯变性淀粉对荞麦挂面烹煮、质构特性的影响

以荞麦-小麦混合粉为原料,研究木薯醋酸酯淀粉、马铃薯醋酸酯淀粉在不同添加量下对荞麦挂面品质的影响。两种醋酸酯淀粉均可显著降低荞麦挂面的烹煮损失,提高吸水率(p<0.05)。两种醋酸酯淀粉的添加量与荞麦挂面硬度、内聚性、胶着性极显著负相关,而与荞麦挂面的弹性呈极显著正相关,但与咀嚼性无显著相关性。     

湿热和韧化处理对荞麦淀粉结构及消化特性的影响

为研究湿热和韧化改性荞麦淀粉的消化机制,分别在体系水分含量为15%、20%、25%、30%,温度为100℃的条件和料液比为1:5,体系温度为30℃、40℃、50℃、60℃对荞麦淀粉进行湿热和韧化处理,测定了湿热和韧化处理前后荞麦淀粉的理化性质和消化特性。结果表明：湿热和韧化处理并未改变荞麦淀粉原有的A-型结晶结构,但淀粉的糊化焓显著降低,从7.96J/g分别降低到6.68J/g和2.77J/g。微观结构表明,淀粉颗粒表面出现裂痕和凹陷。同时,经过湿热和韧化处理后的荞麦淀粉中慢消化淀粉（SDS）和抗性淀粉（RS）含量出现不同程度的改变,表现为湿热处理过程中SDS含量增加（HMT-25,HMT-30除外）,RS含量减少,而韧化处理只有（ANN-50）提高了RS的含量,SDS含量也出现了增加（ANN-40,ANN-60除外）。结论：荞麦淀粉可以通过湿热和韧化改变理化结构从而改变消化速率。     

荞麦萌动过程中淀粉黏度变化规律的研究

探究荞麦萌动的方法,并选取萌动1d和2d的荞麦进行淀粉黏度变化规律的研究,研究结果显示,甜荞粉和萌动甜荞粉最易形成淀粉糊,萌动1d的甜荞粉黏度较高、稳定性好,萌动1d的甜荞冷胶黏度虽然稍低于苦荞,但其稳定性最好,试验为进一步了解萌动荞麦粉淀粉的特性及应用开发提供了一定的理论依据。     

Effects of high hydrostatic pressure on the structure and retrogradation inhibition of oat starch

As a non-thermal processing technology, high hydrostatic pressure (HHP) can be used for starch modification without affecting the quality and flavour constituents. The effect of HHP on starch is closely related to the treatment pressure of HHP. In this paper, we investigated the impacts of HHP treatment pressure (0, 100, 200, 300, 400, 500, 600 MPa) on the microstructure and retrogradation characteristics of oat starch, established the retrogradation kinetic model and elaborated the mechanism of HHP treatment inhibiting the retrogradation of oat starch. Results show that HHP treatment caused the microstructure of oat starch experienced crystallisation perfection (100–300 MPa), crystallisation destruction (400 MPa), crystallisation disintegration and gelatinisation (500–600 MPa). Results of oat starch retrogradation showed that, after treated at 500 MPa for 15 min, the recrystallisation rate of oat starch was reduced, the formation of nuclei at the early stage of oat starch retrogradation suppressed and its nucleation mode was changed from instantaneous to spontaneous, otherwise, the mobility of water in oat starch gel system reduced. Therefore, 500 MPa treated for 15 min can inhibits the retrogradation of oat starch. This study provides theoretical guidance for the application of HHP technology in starch modification and food processing.     

Nonthermal starch hydrolysis using ultra high pressure: I. Effects of acids and starch concentrations

Corn starches with 2 mol/l hydrochloric acid (HCl), 2 mol/l sulfuric acid (H₂SO₄) and 2 mol/l oxalic acid (C₂H₂O₄) were pressurized at 600 MPa for 30 min. Corn starch with C₂H₂O₄ formed a gel after ultra-high-pressure (UHP) treatment. Corn starch with HCl showed partial disintegration but starch with H₂SO₄ maintained its shape. Corn starch with HCl showed higher (0.42-0.47) degree of hydrolysis compared to starch with C₂H₂O₄ (about 0.14) and H₂SO₄ (0.13-0.14) regardless of increasing starch concentration up to 20 g/100 g sample. Main component of starch hydrolysate was maltose for HCl and oligosaccharides for H₂SO₄ and C₂H₂O₄. Crystallinity of starch with HCl decreased with decreasing starch concentration as observed by both differential scanning calorimetry (DSC) and X-ray diffraction. Therefore, UHP can be used for nonthermal starch hydrolysis and HCl would be a good catalyst for UHP starch hydrolysis compared to H₂SO₄ and C₂H₂O₄. This work provides a potential of nonthermal UHP processing for new starch hydrolysis method.     

制备荞麦淀粉醋酸酯的研究

本研究以荞麦淀粉为原料制备荞麦淀粉醋酸酯 ,探讨了荞麦淀粉乳浓度、醋酸酐用量、氢氧化钠浓度、反应液 pH值、反应温度和反应时间对荞麦淀粉酯化的影响 ,通过正交试验 ,确定合成荞麦淀粉醋酸酯最优工艺条件。     

动态超高压微射流对蜡质大米淀粉理化性质的影响

以蜡质大米淀粉为研究对象,采用动态超高压微射流进行处理,研究不同压力对蜡质大米淀粉理化性质(淀粉粒径、溶解度、膨胀度等)的影响.结果表明:动态超高压微射流处理后淀粉颗粒粒度减小,经过160MPa处理后,平均粒径为0.43μm;经过160MPa处理后,比表面积达1.271123m2/g;蜡质大米淀粉的溶解度和膨胀度随着处理压力的增大而显著增大.     

荞麦淀粉生产技术的研究

对荞麦淀粉的生产工艺、生产方法及工艺参数进行了研究;分析测定了荞麦淀粉的理化特性;论述了荞麦淀粉的特性及应用。对指导生产和开发荞麦淀粉提供了有益的参考,为杂粮加工和精深加工开辟了新的途径。     

制备荞麦淀粉醋酸酯的研究

本研究以荞麦淀粉为原料制备荞麦淀粉醋酸酯,通过正交试验,确定合成荞麦淀粉醋酸酯最优工艺条件。     

贮藏温度对高温高压海参体壁组织结构变化的作用

为研究贮藏温度对高温高压海参体壁组织结构变化的影响,将预处理后的刺参组织分别在4、20、37、50和60℃进行恒温贮藏。通过质构(texture profile analysis,TPA)参数、水分状态、扫描电镜(scanning electron microscopy,SEM)和透射电镜(transmission electron microscopy,TEM)图像的变化情况,研究贮藏温度对高温高压海参体壁稳定性的影响。结果表明,高温高压热处理过程中微生物和内源酶已完全失活,并且在贮藏0～30 d过程中仍然保持失活状态。在高温高压热处理过程中,胶原纤维束的结构被破坏,胶原蛋白的三螺旋结构也逐渐解旋和降解。在贮藏过程中,胶原纤维束和胶原蛋白的结构被进一步破坏和降解,且被破坏的程度与贮藏温度呈正相关。因此,可以通过降低贮藏温度进而有效地减小对组织结构的破坏程度,从而延长高温高压海参产品的货架期。     

纳米金刚石-立方相氮化硅烧结体的高温高压制备与表征

采用直接相变的方法制备出了纳米金刚石-立方相氮化硅的烧结体。将石墨与六方相氮化硅的混合粉末经氮气保护球磨26小时后,在约18 GPa、2000℃的压力/温度条件下进行烧结。对烧结产物的X射线衍射分析和扫描电镜分析表明,烧结体中的石墨和六方相氮化硅全部转变成纳米金刚石和纳米立方相氮化硅。烧结体的硬度测试结果显示其平均维氏硬度约为39 GPa。     

天然淀粉的超高压糊化压力研究

在悬浮液浓度为5%(w/v),温度为(20±2)℃时,对8种不同淀粉进行高压处理5 min使淀粉发生糊化,采用X射线衍射测试技术得到了各种淀粉完全糊化的压力:小麦淀粉和木薯淀粉约为500 MPa,玉米淀粉、荸荠淀粉、糯小麦淀粉和糯米淀粉均为550 MPa,糯玉米淀粉约为650 MPa,马铃薯淀粉为750 MPa.     

苦荞麦淀粉微球的制备及表征

目的:优化苦荞麦淀粉微球的制备工艺和性能。方法:正交实验法优化交联淀粉微球的最佳工艺,红外、扫描电镜和粒度分析对其进行表征。结果:制备苦荞麦淀粉微球的最佳条件为:5%苦荞麦淀粉、0.9gSpan60、3mL环氧氯丙烷、反应温度60℃、反应时间为4h。在该条件下制备的淀粉微球近似球状,球体表面粗糙,结构呈多孔立体网络结构,平均粒径为32μm;其对次甲基蓝的吸附量为3.78mg/g。结论:苦荞麦淀粉微球粒径分布均匀,具有良好的吸附和缓释性能,可应用于药物载体。     

苦荞淀粉糊化性质的研究

通过使用DV-T2黏度温控一体机测定苦荞淀粉在不同溶剂中黏度的变化曲线.结果 表明,苦荞生粉的热稳定性、凝胶性较早餐粉苦荞强,更易回生;以硬度高的水为溶剂时苦荞淀粉的热稳定性较好,凝胶性较弱,不易回生;以柠檬酸溶液或食盐溶液为溶剂时,苦荞淀粉的热稳定性随浓度的升高而增强,凝胶性随浓度的升高而减弱,不易回生;以蔗糖溶液为...     

Effects of high hydrostatic pressure on the RS content of amaranth,quinoa and wheat starch

RS exerts a range of beneficial effects on human health. Therefore, ways to increase the RS content in processed food products are looked for. The effects of high hydrostatic pressure treatments on the RS content of wheat, quinoa and amaranth starch were analysed in this study. A 2³ factorial screening design of experiments was used. Experimental factors were pressure (100–600 MPa), temperature (40–60°C) and time (10–30 min). RS in wheat starch increased with increasing pressure by a factor of up to 10 to a value of 4%. In detail, RS content increased significantly at pressures higher than 100 MPa in wheat starch, whereas in quinoa starch significant changes occurred at pressures above 350 MPa (up to 3.3% RS compared to 0.2% in native quinoa starch). Contrary, in amaranth starch the RS content of all pressure treated samples (about 0.5%) was lower than that of the native starch (1.3%). Wheat starch granules swelled to a maximum of 3.67 times their original size and quinoa starch up to 3.36 times. The extent of swelling (2.90) was lowest in amaranth starch.     

氧化淀粉对小麦面团品质变化影响研究

通过对面筋强度、巯基和二硫键含量测定、面筋蛋白电泳观察分析及面团流变学特性变化,研究氧化淀粉对小麦面团品质特性影响。结果表明,氧化淀粉能增加面筋乳酸溶涨值和透光率,提高面筋强度;对面筋蛋白具有氧化作用,增加大分子麦谷蛋白亚基含量,对面团粉质特性影响不显著;但能改善面团拉伸性能,其中以羧基含量为0.27%至0.40%氧化度氧化淀粉对面团品质变化影响最为显著。