油炸过程中淀粉功能特性的变化

采用深层油炸模型,研究了油炸过程中淀粉的溶解度、膨胀度、冻融稳定性和透光率等功能特性的变化。结果表明,在试验范围内,初炸100 s的淀粉溶解度最高,其次是初炸75 s的淀粉,复炸80 s的淀粉溶解度最低。随冻融循环次数的增加,不同油炸处理淀粉的析水率均增大,但不同处理的淀粉析水率增幅不同;初炸25 s的淀粉糊析水率始终高于其他油炸处理的淀粉。当初炸时间在25~75 s时,淀粉的透光率随初炸时间的延长,而逐渐增大;随复炸时间的增加,淀粉的透光率却逐渐下降。     

亚麻籽胶对玉米淀粉糊化特性的影响

采用差示扫描量热仪(DSC)、傅里叶变换红外光谱分析(FT-IR)、X射线衍射分析(XRD)和扫描电子显微镜(SEM)研究添加亚麻籽胶对玉米淀粉糊化的影响。DSC结果表明,添加亚麻籽胶显著地提高了玉米淀粉的糊化起始温度和熔晶热焓值;FT-IR结果表明,添加或未添加亚麻籽胶玉米淀粉结构没有发生变化,在65℃时,亚麻籽胶和玉米淀粉之间没有发生明显的相互作用,在75℃时添加亚麻籽胶促进了淀粉分子结合水的能力增强;X射线衍射分析显示,糊化前添加亚麻籽胶玉米淀粉相对结晶度没有太明显变化,糊化能显著降低玉米淀粉的结晶度,同时也表明添加亚麻籽胶对玉米淀粉糊化有一定延迟作用;SEM也直观地证明了亚麻籽胶延缓了玉米淀粉的糊化。     

海藻酸钠和低甲氧基果胶抑制油炸甘薯淀粉吸油效果及结构变化（网络首发、推荐阅读）

为探明海藻酸钠（sodium alginate,AG）和低甲氧基果胶（low methoxyl pectin,LMP）对油炸甘薯淀粉吸油率的影响,使用低场核磁共振仪、激光共聚焦显微镜、X射线衍射仪、红外光谱及差示扫描量热仪分别分析了添加0.5%（w/w）、2%（w/w）AG和2%（w/w）LMP的油炸甘薯淀粉的油含量及其分布、热性质等。结果表明,添加AG或LMP可以显著降低油炸甘薯淀粉总油含量,油主要分布在淀粉颗粒表层,淀粉结晶类型由A+V型变为V型,糊化焓和相对结晶度明显降低。与添加LMP的油炸甘薯淀粉相比,添加AG后总油含量、相对结晶度和糊化焓更低。添加AG质量分数为2%时,油炸甘薯淀粉糊化程度最高,淀粉颗粒表层呈连续、致密结构,总油含量和表层油含量均为最低。可为健康、低脂油炸淀粉类食品加工提供参考。     

油炸过程中挂糊油炸猪肉片外壳食用品质的变化

采用深层油炸模型,利用色差仪、脂肪测定仪和质构仪等分析测试手段,研究了油炸过程中挂糊油炸猪肉片外壳的表观色度、水分含量、含油率及硬度、脆度和易碎性等质构参数的变化。试验结果表明,随油炸温度的升高和时间的延长,挂糊油炸猪肉片外壳的白度(L*值)逐渐降低,红度(a*值)和黄度(b*值)不断增加;复炸时间较短时,产品外壳白度较高,黄度较低;复炸时间过长时,油炸产品外壳红度过高。质构分析显示,随复炸时间的增加,油炸食品外壳的硬度增大,脆性和易碎性得到改善。此外,挂糊油炸猪肉片外壳的含油率与水分含量之间具有负相关关系,相关系数(R2)高达0.981。就色度、含油率和质构而言,在初炸100 s和复炸40-60 s的条件下,制备的挂糊油炸猪肉片外壳具有较高的食用品质。     

超高压处理对玉米淀粉结构及糊化特性的影响

利用光学显微、X-射线衍射、差示扫描量热、快速黏度分析技术研究了超高压处理对玉米淀粉结构及糊化性质的影响。结果显示,超高压处理能使玉米淀粉糊化,处理压力为500 MPa及600 MPa时完全糊化所需保压时间分别为15 min和5 min,但400 MPa超高压处理30 min也不会使淀粉糊化。超高压糊化过程中,淀粉颗粒结构逐渐破坏膨胀,结晶结构由A型向V型转化,RVA黏度曲线峰值黏度逐渐消失。适宜条件的超高压处理对淀粉颗粒同时具有韧化和晶体破坏作用。其中,400 MPa超高压处理5~10 min时,淀粉颗粒内部韧化作用占优,因而表现为相对结晶度、糊化温度(T_o,T_p)及糊化焓增加,而RVA曲线峰值黏度降低。     

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％。     

部分糊化玉米淀粉浆液的性能

以玉米淀粉为原料,采用蒸汽升温法制备部分糊化淀粉浆液。运用光学显微镜、粒度分析仪、差示热分析仪、X射线衍射仪等对原淀粉和用蒸汽升温法于不同温度下制备的部分糊化淀粉浆液的形态结构、颗粒大小、膨胀势、糊化度、结晶度等进行了测试和比较。结果表明:随着制备温度的提高,部分糊化淀粉浆液的偏光十字逐渐消失,结晶度下降,而糊化度、粒径、膨胀势逐渐增大;64℃时制备的稳定性较好的部分糊化淀粉浆液的大部分偏光十字消失,但仍有结晶峰存在,糊化度为72.22%。     

烤烟烟叶淀粉颗粒结构特征与基本特性

为明确烟叶淀粉颗粒结构和特性,合理调控烤后烟叶淀粉含量,采用环境扫描电子显微镜、X-射线衍射仪和同步热分析仪测定了云烟87、中烟103和中烟202三个品种田间成熟烟叶的淀粉颗粒结构特征、晶体特性和热特性。结果表明:三个品种田间成熟烟叶淀粉颗粒主要为圆球形和长圆柱状,个别呈不规则形状,平均粒径为3～4μm;长圆柱状和不规则形状的淀粉颗粒上存在明显的层状结构,且中烟103和中烟202两个品种的烟叶淀粉表面的层状结构明显多于并较云烟87明显;X-射线衍射均为"B"型模式,品种间相对结晶度差异明显;烟叶淀粉颗粒的糊化起始温度较低,但糊化峰值温度、终止温度和糊化焓较高,三个品种之间的各糊化温度略有差异,但糊化焓差异较大;热焓值随着结晶度的降低而降低。     

响应面法优化锅包肉炸制工艺

目的 优化锅包肉炸制工艺。方法 以质构、色差、理化、感官为评价指标, 采用单因素试验考查淀粉种类、初炸温度、初炸时间、复炸温度、复炸时间对锅包肉品质的影响, 通过响应面法优化锅包肉的最佳工艺参数。结果 各影响因素对锅包肉的影响顺序为: 复炸温度>初炸时间>初炸温度>复炸时间, 初炸温度与复炸温度、初炸温度与复炸时间、初炸时间与复炸温度交互作用对感官评分的影响显著。最佳工艺条件为: 选用马铃薯淀粉, 通过初油炸温度175 ℃、初炸时间100 s、复炸温度210 ℃、复炸时间50 s, 在此条件下油炸锅包肉颜色均匀金黄、香气浓郁、软硬适中、具有良好的脆性和感官品质, 感官评分为98.40分。结论 优化后的工艺具有可行性, 可为锅包肉的工业化加工提供一定的理论依据。     

黑曲霉发酵法制备小红栲多孔淀粉

对黑曲霉发酵法制备小红栲多孔淀粉的工艺进行了研究,并分析了多孔淀粉的形态结构、晶体特征和糊化特性。试验结果表明,在发酵培养基母液体积分数为90%的培养基中,当黑曲霉发酵至第48 h时,加入质量分数为7.0%的原淀粉后继续发酵56 h,由此制得小红栲多孔淀粉。小红栲多孔淀粉的形成过程是:酶作用于淀粉颗粒表面的凹坑形成孔洞,由浅入深,直达颗粒中心,最终形成彼此相连的桥形网状空洞结构,其上分布着孔径1μm左右的孔洞。小红栲原淀粉与多孔淀粉的X-射线衍射图谱由尖峰衍射特征和弥散衍射特征两部分组成,属C-型晶体。多孔淀粉比原淀粉的结晶度、微晶尺寸和吸热焓要大,而微晶间距和糊化温度则小。     

高速射流对木薯淀粉结构和性能的影响

以粒度分析、扫描电子显微镜(SEM)、X-射线衍射(XRD)、扫描示差量热(DSC)为分析手段,研究了木薯淀粉经不同压力(60、100、140、180、220 MPa)高速射流处理2次对木薯淀粉的粒度、微观结构、冻融稳定性、溶解性及DSC曲线的影响。结果表明:木薯淀粉经高速射流处理后,颗粒结构被严重破坏,发生部分糊化,粒度显著增加,溶解性提高,但冻融稳定性下降;高速射流处理并不改变木薯淀粉的晶形,但其结晶度降低。     

油炸对马铃薯淀粉特性的影响

本文采用直接油炸淀粉的方法,研究不同油炸温度对马铃薯淀粉结构和性能的影响。采用电子扫描显微镜(SEM)、偏光显微镜、X-射线衍射仪(XRD)、Brabender 粘度仪等对油炸处理后淀粉的颗粒形态、结晶结构、糊化性质、透明度及冻融稳定性等进行测定分析。结果表明,随着油炸温度的升高,马铃薯淀粉的颗粒表面结构发生了明显的变化,淀粉颗粒表面出现凹陷、膨胀和破裂,样品的偏光十字双折射强度减弱,甚至消失;油炸破坏了淀粉的结晶结构,180℃油炸淀粉结构变化最显著,最适于淀粉的消化吸收;随着油炸温度的升高,样品粘度逐渐降低,且峰值粘度小于原淀粉;油炸淀粉的透光率较低,冻融稳定性较差,且均低于原淀粉,油炸淀粉类食品不适于冷冻。     

Physicochemical,crystalline, and thermal properties of native and enzyme hydrolyzed Pueraria lobata (Willd.) Ohwi and Pueraria thomsonii Benth. starches

Starches isolated from the bulbs of Pueraria lobata (Willd.) Ohwi (PLO) and Pueraria thomsonii Benth. (PTB) were hydrolysed by glucoamylase for different lengths of time (2, 4, 8, 12, and 24 h). The hydrolysis results were compared by scanning electron microscope (SEM), X‐ray power diffractometer (XRD), and differential scanning calorimetry (DSC). The SEM results revealed that both of the PLO and PTB starches showed the same hydrolysis mechanism, which indicated that the glucoamylase primarily attacking the exterior of starch granules and then the interior. The results of XRD revealed the crystalline type of PTB starch changed from C‐type to A‐type with crystallinity reducing from 43.5 to 20.9% during the hydrolysis. Unlike PTB starch, the PLO starch did not show marked changes in crystalline style but lower degree of crystallinity was obtained from 32.4 to 13.7% during the hydrolysis. All the XRD results demonstrated that B‐type polymorph was preferentially degraded than A‐type polymorph in the C‐type starch. The DSC results revealed that both of the PLO and PTB starches showed decreased enthalpy of gelatinization (ΔH_gel) and gelatinization temperature range (R)‐value after hydrolysis, while the gelatinization temperature (T_p) indicated different tendency, initially ranging from 68.6 to 64.3°C and then increasing to 67.8°C for PLO starch. While for PTB starch, the T_p‐value showed progressive reduction from 85.4 to 74.3°C during the whole process.     

加酶挤压对小麦淀粉结构和理化性质的影响

本文旨在探究加酶挤压对小麦淀粉结构和理化性质的影响。分别设置浓度梯度为0%、0.1%、0.2%、0.5%、1%、2%的α-淀粉酶-小麦淀粉混合物样品,挤压处理后,利用扫描电镜（SEM）、差示扫描量热仪（DSC）、X-射线衍射仪（XRD）、快速粘度仪（RVA）等分析淀粉结构与理化性质的变化。结果表明:各处理组的堆积密度无显著差异（P>0.05）;吸水指数与加酶量呈负相关,水合指数与加酶量呈正相关;挤压后淀粉糊化度均大幅度提高,接近完全糊化;挤压后淀粉的颗粒结构被完全破坏且加酶使得淀粉颗粒粒径更小;加酶挤压处理后相对结晶度降低,从原淀粉的17.52%降至10.29%（酶浓度2%）;挤压处理后小麦淀粉的糊化焓均显著下降（P<0.05）,挤压淀粉样品焓值最低,仅为0.24 J/g,加酶挤压淀粉的焓值高于挤压淀粉,随着加酶量的增加,淀粉的焓值上升至2.5 J/g左右;RVA曲线可明显看出处理组的粘度远低于原淀粉粘度,且加酶挤压样品粘度低于不加酶挤压粘度。本文探明了加酶挤压对淀粉结构和理化性质的作用规律,可为加酶挤压技术在淀粉基食品领域的应用提供理论指导。     

Effect of high‐pressure microfluidization on the structure of cassava starch granule

Microfluidization has been applied to modify starch granules. The study was conducted to investigate the effect of microfluidization on the structure and thermal properties of cassava starch–water suspension (20% w/w). The means of optical microscopy, SEM, FTIR spectroscopy, XRD, and DSC were applied to analyze the changes in microstructure, crystallinity, and thermal property. Microscopy observations revealed that native starch granules were oval, round, and truncated in shape. After the microfluidization treatment, a bigger starch granule was partially gelatinized, and a gel‐like structure was formed on a granular surface. No significant difference in XRD patterns of the samples were observed and all samples exhibited A‐type allomorph. Crystallinity decreased with the pressure. Sample treated at 150 MPa contains 17.1% crystalline glucan polymer, lower than that of native granules which have crystallinity of about 25.8%. A lower crystallinity means poor order of crystalline glucan polymer structure in starch granules. The disruption of crystalline order within the granule was also observed by FTIR measurement. Thermal analysis using DSC indicated that the microfluidization treatment brought about a significant decrease of melting enthalpy. The gelatinization enthalpy was 12.0 and 3.0 J/g for the native sample and samples treated under the 150 MPa, respectively. The results indicate that high‐pressure microfluidization process induced the gelatinization of cassava starch, which is evaluated by a percentage of the degree of gelatinization, due to a pronounced decrease with increasing microfluidizing pressure.     

Effect of alkali treatment on structure and function of pea starch granules

The effect of alkaline treatment on the structural and functional properties of pea starch granules was studied using a range of characterization methods including amylose content, scanning electron microscopy (SEM), X-ray diffraction (XRD), (13)C nuclear magnetic resonance (NMR), swelling power, differential scanning calorimetry (DSC), the Rapid Visco Analyser (RVA) and in vitro digestibility. The amylose content decreased by about 20-25% after 15days of alkaline treatment and there were small decreases in relative crystallinity and double helix content. Deformations were observed on the surface of alkali-treated granules, and there was evidence of adhesion between some of the granules. There was a 25-30% reduction in peak and final RVA pasting viscosities, but only a small reduction in swelling power. The endothermic transition of alkali-treated starch was broadened with a shift of the endothermic peak to higher temperature. However, the endothermic enthalpy remained largely unaffected. Alkali-treatment greatly increased the rate of in vitro enzymatic breakdown of the pea starch. More prolonged alkaline treatment for 30days did not cause further significant changes to the structural and functional properties of the starch granules. The effects of alkali on structure and function of pea starch are explained on the basis of limited gelatinization of the granules.     

马铃薯抗性淀粉的微波-湿热制备工艺优化及结构表征

以马铃薯淀粉为原料,采用微波-湿热法制备马铃薯抗性淀粉。考察了淀粉乳质量分数、微波功率、微波时间对马铃薯抗性淀粉得率及结构的影响。结果表明,在微波时间240 s、微波功率750 W、淀粉乳质量分数15%条件下,马铃薯抗性淀粉的最大得率为9.77%。通过扫描电镜、红外光谱、X-射线衍射分析表明,马铃薯淀粉颗粒完整性被破坏,结晶结构改变,结晶度增加;马铃薯淀粉经微波-湿热处理后,未有新的官能团产生,但分子间氢键发生变化。     

Physical,Thermal and Sorption Profile of Starch Obtained from Tacca leontopetaloides

The purpose of this study was to elucidate functional properties of starch granules obtained from tubers of Tacca leontopetaloides and compare them to a commercially available maize starch. Scanning electron microscopy (SEM), particle size analysis, X‐ray powder diffraction (XRPD), gravimetric moisture sorption, and differential scanning calorimetry (DSC) were used to characterize the samples. Tacca starch exhibited a monomodal distribution of irregularly shaped granules with a mean particle size of 2.64 µm. The spherulites of both samples indicated an A‐type pattern, with the degree of crystallinity estimated to be 35% for tacca starch and 38% for maize starch. The moisture sorption profile of both samples was analyzed according to the Guggenheim, Anderson and de Boer (GAB) equation. GAB analysis estimated the monolayer coverage for tacca and maize starch to be 0.0928 g/g and 0.0856 g/g, respectively. The gelatinization parameters of tacca starch were found to be 65.57 – 68.56 – 73.10°C while that of maize starch were 67.30 – 70.97 – 76.25°C. The results of DSC studies indicate that the associative forces that stabilize the granule structure in tacca starch are weaker than those in maize starch. The results obtained in this study establish the fundamental characteristics of tacca starch and suggest that further exploration of its potential for use in a variety of fields is warranted.     

挤压剪切活化对添加耐高温α-淀粉酶脱胚玉米淀粉结构和理化特性的影响

本研究通过偏光显微镜、扫描电子显微镜、热台显微镜、X射线衍射、差示扫描量热分析、傅里叶变换红 外光谱分析等手段,研究原脱胚玉米、挤压脱胚玉米和添加耐高温α-淀粉酶挤压脱胚玉米的淀粉结构及性质变化, 并探究其相互关系,揭示挤压剪切活化对脱胚玉米的淀粉颗粒机械力化学效应。研究表明：与原脱胚玉米和挤压脱 胚玉米相比较,挤压处理对添加耐高温α-淀粉酶脱胚玉米的淀粉结构及性质产生显著影响,酶解力和糊化度增大,碘 蓝值、直链淀粉含量减小。添加耐高温α-淀粉酶挤压脱胚玉米淀粉颗粒形貌破坏,偏光十字破坏,结晶度变小;升温糊 化过程中,焓变降低;挤压使淀粉颗粒的结晶结构破坏,淀粉颗粒发生聚集,破损淀粉颗粒易糊化和裂解。     

微波对板栗淀粉结构和理化性质的影响

为探讨微波辐照对板栗淀粉颗粒结构和理化性质的影响,采用微波辐照板栗淀粉,通过扫描电镜(SEM)、X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FTIR)、差示扫描量热仪(DSC)等研究微波处理不同时间后板栗淀粉的颗粒结构和理化特性。研究表明:与原淀粉相比,微波处理后板栗淀粉的微观形貌发生明显变化,但淀粉颗粒仍为C型晶体。随着微波处理时间的增加,直链淀粉含量增大,淀粉颗粒表面出现裂纹、孔洞和黏结越显著,淀粉颗粒的相对结晶度降低、红外光谱(1 047/1 022)cm~(-1)峰强度比值降低;淀粉膨胀度和透光率也随微波处理时间的增加而降低。DSC分析表明,微波处理80 s的淀粉相转变温度(T_o和T_p)降低、糊化焓(ΔH)减少。表明微波辐照对板栗淀粉的颗粒结构和理化特征均有显著影响。