羧甲基纤维素钠的种类和用量对干热变性淀粉糊化性质的影响

研究玉米淀粉、M202,Cocodrie,CM101和土豆淀粉与1%CMC、2%CMC的混合物在130℃下干热反应4 h后,干热变性淀粉的糊化特性和粒径的变化.除土豆淀粉外,其它4种淀粉在1%低黏度CMC存在的条件下,130℃处理4 h后,淀粉糊化的起始温度都有所降低,糊化的峰值黏度和终黏度都升高了;用2%低黏度的CMC或1%中黏度的CMC干热处理,淀粉的糊化黏度反而降低了;如果使用2%中黏度的CMC,淀粉几乎不糊化.在干热过程中,离子胶可以作为交联剂与两个或多个淀粉分子连接,生成交联淀粉.     

黄原胶协同干热变性对紫薯淀粉特性的影响

为开发强度高、透明度好且阻水能力优的可食性淀粉膜,本试验添加黄原胶对紫薯淀粉进行干热变性处理,研究其产物特性的变化。结果表明:黄原胶协同干热变性处理后的紫薯淀粉颗粒略微膨胀,大小不均一且发生粘连现象;糊化起始温度略有降低,峰值黏度与终值黏度均升高,热稳定性提高;淀粉糊的冻融稳定性显著提高,溶解度和膨胀度降低,且透明度有所降低;淀粉糊的流变曲线表现为逆时针环状,屈服应力明显增大,其形成的凝胶呈现固体特征,储能模量G'增加,剪切结构恢复力显著提高;淀粉属C-型晶体,干热处理前后淀粉的X-射线衍射图谱无明显变化,但干热变性处理使淀粉结晶度增大。因此,添加黄原胶对紫薯淀粉进行干热变性,可使产物的特性发生明显改变。     

干热变性莲子淀粉制备工艺对其成膜特性影响的研究

通过将莲子淀粉与海藻酸钠混合均匀后干热反应制得干热变性莲子淀粉,并以其为主要原料制备可食膜,研究不同离子胶用量、反应pH、干热处理的温度和时间对干热变性莲子淀粉成膜特性的影响,确定干热变性莲子淀粉的制备工艺.结果显示:添加海藻酸钠对莲子淀粉进行干热变性处理能改善莲子淀粉的成膜特性,pH和干热温度对干热变性莲子淀粉的成膜性影响最显著.经正交试验优化,当海藻酸钠质量分数为1.0％、pH 7、130℃条件下干热反应3h时制备的干热变性莲子淀粉成膜特性最优,为海藻酸钠与莲子淀粉干热反应的最佳工艺参数.     

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。     

不同添加量的氨基酸辅助干热处理对玉米淀粉理化和消化性质的影响（网络首发、推荐阅读）

以玉米淀粉为原料,通过氨基酸（天冬氨酸和赖氨酸）辅助干热处理对其改性,采用快速黏度仪、差式扫描量热仪、X射线衍射仪,对不同氨基酸添加量（0.5%、2%、4%和10%,w/w）的干热玉米淀粉的糊化特性、热特性、结构特性和消化性质进行了研究。结果表明,氨基酸添加量对干热处理玉米淀粉-氨基酸混合物的理化性质和消化性质有显著影响。随着两种氨基酸添加量的增多,淀粉的峰值黏度、回生值和糊化焓值降低,而相对结晶度和抗性淀粉含量升高;干热玉米淀粉-天冬氨酸混合物的糊化温度呈先升高而后降低的趋势,干热玉米淀粉-赖氨酸混合物的糊化温度呈升高趋势。提高氨基酸添加量能促进淀粉颗粒内部的晶体排列更紧密、有序,能更好地抑制淀粉的短期老化,降低淀粉的消化性能;可作为玉米淀粉改性的一种新方法,为生产改性淀粉提供参考。     

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。     

几种不同淀粉的物性分析研究

以玉米淀粉、蜡质玉米淀粉、马铃薯淀粉、马铃薯酯化变性淀粉、木薯淀粉和木薯醋酸酯淀粉为原料,比较研究了激光粒度仪和X-射线衍射仪测定的淀粉的颗粒大小和结构,快速粘度仪测定糊化特性,差示扫描量热仪和热重分析仪测定淀粉的热特性。结果表明,淀粉的平均粒径大小顺序为马铃薯类淀粉玉米类淀粉木薯类淀粉,且湿法和干法测定有差异;玉米淀粉、木薯淀粉和木薯醋酸酯淀粉为A型结构,蜡质玉米淀粉经过变性处理无双峰结构,马铃薯及其酯化变性淀粉为B型结构;马铃薯淀粉峰值粘度最大,热焓值最高,持水力最强,玉米淀粉的糊化温度最高,峰值粘度和衰减值最小,马铃薯酯化淀粉的起始糊化温度最低,综合持水力最弱。     

食品胶协同干热处理对马铃薯淀粉理化特性的影响

为了改善马铃薯淀粉加工特性,选用瓜尔胶、羧甲基纤维素钠和黄原胶3种食品胶分别与马铃薯淀粉复配后进行干热处理,研究食品胶协同干热处理对马铃薯淀粉糊化、老化和流变特性的影响。研究发现,中3种食品胶协同干热处理均能够降低糊化温度与糊化焓,并且均能增强淀粉体系稳定性,使其呈现出弹性流体性质,不仅如此还均能提高淀粉糊热稳定性以及耐剪切能力,此外均能增强淀粉凝胶的冻融稳定性。结果表明,3种食品胶协同干热处理均能起到改善马铃薯淀粉加工特性的作用,对其改善程度对比分析发现,黄原胶协同干热处理改善马铃薯淀粉特性效果最好。     

不同离子胶对玉米磷酸酯双淀粉性质的影响

研究了离子胶(羧甲基纤维素钠、海藻酸钠、卡拉胶、壳聚糖)不同添加量(0∶1、1∶9、3∶7)对玉米磷酸酯双淀粉糊化特性、凝胶质构特性、溶胀度和吸油率等性质的影响。结果表明,阴离子胶(羧甲基纤维素钠、海藻酸钠、卡拉胶)降低了玉米磷酸酯双淀粉的峰值黏度、衰减值;而阳离子胶(壳聚糖)使玉米磷酸酯双淀粉的峰值黏度、衰减值显著增加。阴离子胶使玉米磷酸酯双淀粉凝胶硬度下降,而壳聚糖则使其凝胶硬度上升。阴离子胶能促进玉米磷酸酯双淀粉的溶胀,但壳聚糖抑制其溶胀。壳聚糖使玉米磷酸酯双淀粉吸油率增加。离子胶对玉米磷酸酯双淀粉性质的影响,不仅与离子胶自身性质有关,而且可能与二者之间的静电作用密切相关。     

DSC法测定水分含量对玉米淀粉糊化和老化特性的影响

建立差示扫描量热法(DSC)测定玉米淀粉糊化的方法,在升温速率和温度范围分别为10℃/min和45～95℃的条件下,研究不同水分含量对玉米淀粉糊化和老化特性的影响。结果证明玉米淀粉水分含量越高,其糊化需要的热焓越大;4℃贮存条件下,玉米淀粉老化快;水分含量越大,玉米淀粉老化速率越低。     

Effect of dry heating with ionic gums on physicochemical properties of starch

Corn starch, potato starch, pea starch were impregnated with ionic gums (sodium alginate, CMC, and xanthan, 1% based on starch solids) and heat-treated in a dry state for 0, 2, or 4 h at 130 °C. Effects of the dry heating on paste viscosity (RVA), microstructure and thermal properties were examined. Dry heat treatment with ionic gums reduced the pasting temperature of the three starches. Heating with xanthan increased the paste viscosity of corn and potato starch. With heat treatment, the paste viscosity of all the starch-sodium alginate mixtures decreased. Heating with CMC increased the paste viscosity of potato starch, but decreased that of corn and pea starch. After dry-heating, To, Tp and Tc of potato starch with ionic gums decreased significantly. SEM of potato starch with CMC showed that the gel structure got compacter after drying-heating. Heat treatment obviously improved the functional properties of the three starches.     

Physicochemical properties,resistant starch content and enzymatic digestibility of unripe banana,edible canna,taro flours and their rice noodle products

Unripe banana, edible canna and taro flours, which have been reported to contain significant amounts of fibre, were investigated for their physicochemical properties, resistant starch (RS) content and in vitro starch digestibility, and compared with commercial high‐fibre‐modified starches from corn and tapioca. Differential scanning calorimetry showed a single endothermic peak located around 70–83 °C for the samples except the modified starches, which exhibited no transition enthalpy. The samples showed different pasting behaviours in the Rapid Visco‐Analyser (RVA) ranging from full to restricted swelling. The RS content varied from 1–26 g per 100 g dry sample, and the estimated glycaemic indices (GIs) of the samples were from 67% to 99%. Generally, samples with high RS were low in GI values. The starches produced acceptable rice noodles but with reduced rate of starch digestion and GI. The effects of the unripe banana, edible canna and taro flours on starch digestibility were either comparable or better than the commercial modified starches. These flours can substitute commercial modified starches to lower GIs of noodles and identical foods.     

Effect of ionic gums and dry heating on physicochemical,morphological, thermal and pasting properties of water chestnut starch

Starch from water chestnuts (Trapa natans) was isolated and modified by dry heating and hydrocolloids [carboxy methyl cellulose (CMC) and sodium alginate]. Native and modified starches were evaluated for their physicochemical, pasting, thermal and morphological properties. Pasting and thermal properties were studied using Rapid Visco Analyzer (RVA) and Differential Scanning Calorimeter (DSC) respectively. Morphological properties were studied by Scanning Electron Microscopy (SEM). Modification of the starch by dry heating with and without gums reduced paste clarity and increased the water and oil binding capacity; solubility and swelling power decreased. Dry heating of native starch increased peak viscosity; however, with addition of CMC, peak viscosity decreased. Starch modified with CMC and 4 h heating exhibited lowest gelatinization temperature (T₀). Pasting characteristics of native water chestnut starch were largely affected by the addition of gums and/or heat treatment. Overall onset gelatinization temperature reduced with heat treatment and addition of gums. Morphological studies revealed no significant variation in starch granule size. Starch granules were seen agglomerated because of leaching of amylose and granule interspacing decreased with addition of gums.     

Interaction of Guar and Xanthan Gums with Starch in the Gels Obtained from Normal,Waxy and High‐amylose Corn Starches

The objectives of the present study were to analyze the chemical interactions between guar and xanthan gums and starches. Gels were obtained from normal (NCS), waxy (WCS) and high‐amylose (HACS) corn starches containing gums. The gels were evaluated according to their pasting properties and infra‐red absorption. The guar (GG) and xanthan (XG) gums affected the properties of the NCS paste more significantly than those of the WCS paste. In the infra‐red absorption spectra, no covalent bonds between the starches and gums were observed under the conditions studied, so probably the only interactions occurring between them were hydrogen bonds.     

Effect of acetylation,oxidation and annealing on physicochemical properties of bean starch

Black and Pinto bean starches were physically and chemically modified to investigate the effect of modification on digestibility and physicochemical properties of bean starch. The impact of acetylation, oxidation (ozonation) and annealing on the chemical composition, syneresis, swelling volume, pasting, thermal properties and digestibility of starches was evaluated. The physicochemical and estimated glycemic index (eGI) of the Black and Pinto bean starches treated with ozone were not significantly (P > 0.05) different than that of their respective control starches. Annealed starches had improved thermal and pasting properties compared to native starches. Acetylated starches presented reduced syneresis, good pasting properties and lower eGI. Also, all modified starches had increased levels of resistant starch (RS). Therefore, the digestibility and physicochemical properties of bean starch were affected by the type of modification but there were no significant (P > 0.05) differences between the Black and Pinto bean starches.     

Paste viscosity of rice starches of different amylose content and carboxymethylcellulose formed by dry heating and the physical properties of their films

Starch modified by combination with sodium carboxymethylcellulose (CMC) has been reported to have improved film properties. In this study, rice starches with different amylose content were heat-treated in a dry state after being impregnated with low or medium-viscosity CMC. Noticeable change was found in pasting properties of the starches after dry heat treatment with CMC. It indicated that crosslinkage occurred between the starch and CMC. The waxy starch showed significant change in viscosity throughout pasting after dry heating with CMC, suggesting that the ester bonds were mostly formed between the hydroxyl groups in amylopectin branches of rice starch and carboxylate acid groups of CMC. Particle size also increased after heat treatment with CMC. The modified starch-based films showed improvement in the tensile strength. Both water vapor and oxygen permeability reduced for the modified starch-based films. Dynamic mechanical analysis (DMA) study showed that the values of G′ of modified starch-based film were higher than those of native starch-based film over the temperature range −40 to 60 °C. The heating process with CMC could be used as a modification method for starch and provide desirable properties of starch-based films.     

Physicochemical properties of acetylated starches from some Indian kidney bean (Phaseolus vulgaris L.) cultivars

Starches separated from four kidney bean cultivars were modified by acetylation to reduce retrogradation and increase gel stability and compared with respective native starches (data of native starch reported by Wani et al., 2010 ). Acetylation was carried out by treating starches with 0.04 and 0.08 g of acetic anhydride per gram of starch dry weight basis (dwb) at 25 °C and pH between 8.0 and 8.5. The extent of acetylation increased proportionally with the concentration of acetic anhydride used. The pasting curves of 10.7% starch determined by Rapid Visco Analyzer at 160 rpm showed that acetylation decreased the setback viscosity values by 0.64–34.58% and pasting temperature by 4.4–9.2 °C when compared with the native starch. Differential scanning calorimetry observations also revealed significant (P ≤ 0.05) decrease in gelatinisation temperature of acetylated starches than the corresponding native starches. Hardness of starch gels varied between 14.3 and 44.0 g, which was significantly (P ≤ 0.05) lower than the corresponding native starch gels.     

Pasting Properties of Potato Starch and Waxy Maize Starch Mixtures

The pasting viscosity, morphological properties, and swelling properties of potato starch and waxy maize starch mixtures at different ratios were investigated. Pasting analysis of the starch mixtures (7% solids in water, w/w) using a Rapid Visco Analyser showed linear changes in peak viscosity and pasting temperature according to the mixing ratios of both starches, but not in breakdown and setback. The pasting profile revealed that the starches rendered mutual effects during pasting, more significantly when the amounts of potato and waxy maize starches were similar. The volume fraction of swollen granules and the presence of amylose appeared to be important parameters in the mutual effects of both starched during pasting. Under a light microscope, the swelling of potato starch granules was delayed by the presence of waxy maize starch. Overall results indicate that new pasting properties can be generated by mixing starches of different botanical sources.     

两种大米淀粉及其磷酸酯淀粉理化特性的比较研究

对比分析2种大米(籼米和粳米)的全粉、淀粉和取代度均为0.068的磷酸酯淀粉的理化特性.粳米的全粉、淀粉和磷酸酯淀粉的膨胀力分别为7.5,10.7,21.6 g/g,分别高于籼米的全粉、淀粉和磷酸酯淀粉的膨胀力(5.8,8.9,17.4 g/g).2种大米淀粉经磷酸酯化后透光率增高,相应淀粉的透光率次之,全粉的透光率最低,籼米的全粉、淀粉和磷酸酯淀粉的透光率分别低于粳米的全粉、淀粉和磷酸酯淀粉的透光率.经快速黏度分析仪测定的糊化特性结果表明,淀粉或变性淀粉膨胀力高,其峰值黏度和崩解值也高,此外,蛋白质含量和直链淀粉含量也极大的影响了淀粉的糊化特性.使用动态流变仪测定的流变特性表明,在相同的温度下,籼米的全粉、淀粉和变性淀粉的储能模量(G')分别比粳米的全粉、淀粉和变性淀粉的储能模量(G')高,对于相同的大米品种,全粉的储能模量(G')最高,变性淀粉的储能模量(G')最低.