变性淀粉对速冻水饺质量的影响

分析不同原料(蜡质玉米淀粉、木薯淀粉和马铃薯淀粉)制备的羟丙基淀粉的性能,并将羟丙基蜡质玉米淀粉,羟丙基木薯淀粉和羟丙基马铃薯淀粉分别添加到面粉中,研究其对速冻水饺品质的影响。实验表明:变性淀粉添加量为3%～4%(以面粉干基计),面团含水量为44%～45%时,速冻水饺的冷藏稳定性最好。其中添加羟丙基蜡质玉米淀粉在减少速冻水饺的冻裂率,改善速冻水饺的透明度、光泽和色泽方面效果最明显。     

交联和羟丙基改性对蜡质玉米淀粉糊性能的影响

本研究采用蜡质玉米淀粉为原料,湿法工艺制备了磷酸酯双淀粉(1412)、羟丙基淀粉(1440)和羟丙基二淀粉磷酸酯(1442),通过对蜡质玉米淀粉(WS)和3种变性淀粉(1412、1440、1442)在黏度、抗剪切、耐酸性、冻融稳定性和透明度等性能的比较,探讨了羟丙基醚化和交联改性处理对蜡质玉米淀粉糊性能的影响。试验结果显示:⑴羟丙基改性处理降低了淀粉的糊化温度,提高了淀粉峰值黏度,透明度和冻融稳定性得到显著改善,但热稳定性、耐酸性和抗剪切均较差;⑵磷酸盐交联改性的磷酸酯双淀粉糊化温度升高,峰值黏度降低,糊液在抗剪切、耐酸性方面得到显著改善,但糊液透明度降低,冻融稳定性未得到改善;⑶通过交联和羟丙基改性的羟丙基二淀粉磷酸酯,兼具有磷酸酯双淀粉和羟丙基淀粉的共同特性。     

木薯羟丙基淀粉制备工艺的研究

以木薯淀粉为原料,环氧丙烷为醚化剂,硫酸钠为淀粉膨胀抑制剂,采用湿法工艺制备木薯羟丙基淀粉,以产品摩尔取代度(MS)为评价指标,通过单因素试验分别探讨了环氧丙烷用量、硫酸钠用量、反应pH值、反应温度、反应时间等对羟丙基醚化反应的影响,在此基础上应用正交试验确定了木薯羟丙基淀粉制备的最佳工艺条件。试验结果显示:(1)随环氧丙烷用量的增大,取代度逐渐升高,反应效率逐渐降低;(2)适当提高反应pH和反应温度有利于取代度的提高,但反应pH值超过11.5和反应温度超过45℃,会导致淀粉的局部糊化,不利于醚化反应的进程。制备木薯羟丙基淀粉的最佳工艺条件为:淀粉乳浓度40%,环氧丙烷添加量10%(对干基),硫酸钠添加量12%(对干基),反应pH值11.5,反应温度40℃,反应时间22 h。所得木薯羟丙基淀粉的取代度为0.143。     

交联剂和醚化剂添加量对改性蜡质玉米淀粉性质的影响

目的:为有效控制交联羟丙基淀粉制备过程中交联和醚化程度，改善产品性能。方法:以蜡质玉米淀粉(WCS)为原料，以三偏磷酸钠(STMP)为交联剂、环氧丙烷(PO)为醚化剂，在碱性条件下制备了复合变性淀粉——羟丙基二淀粉磷酸酯(HDP),重点考察了STMP和PO添加量对蜡质玉米淀粉Brabender黏度曲线、透明度、冻融稳定性的影响。结果:通过前期条件探索和研究优化，获得了兼具热稳定性和易糊化特性、冻融稳定性和透明度较单一交联或醚化改性WCS改善的HDP,具体制备条件为：STMP添加量0.30 g/100 g,交联反应时间45 min, PO添加量6 mL/100 g,醚化反应时间90 min。结论:经交联和醚化后的淀粉性能相比原淀粉有了明显的改善，糊化温度降低，冻融稳定性提高，热稳定性和凝胶性均有所增强。     

一步法制备蜡质玉米复合变性淀粉工艺研究

以蜡质玉米淀粉为原料,环氧丙烷为醚化剂,三偏磷酸钠为交联剂,氢氧化钠为催化剂,无水硫酸钠为膨胀抑制剂,采用一步法湿法工艺制备了蜡质玉米复合变性淀粉。研究了环氧丙烷、三偏磷酸钠、氢氧化钠、无水硫酸钠用量对产品取代度和反应效率的影响,结果表明:交联羟丙基复合变性淀粉反应时膨胀抑制剂无水硫酸钠的适宜用量为13%,催化剂Na OH适宜用量为1.2%,醚化剂适宜用量为10%,反应时间为16 h,反应温度为45℃;三偏磷酸钠用量对产品取代度和反应效率影响较小;并制备了羟丙基复合变性淀粉,为蜡质玉米淀粉的应用和变性淀粉的开发提供了理论参考。     

羟丙基玉米淀粉的制备及特性研究

本文研究了用环氧丙烷制备羟丙基玉米淀粉的反应条件以及羟丙基化对玉米淀粉糊特性的影响,在反应条件中,着重研究了淀粉乳浓度、环氧丙烷用量、反应温度和时间对醚化程度以及反应效率的影响规律,试验表明：羟丙基化能大大提高玉米淀粉糊的抗剪切性能和抗盐性能,使淀粉糊的透明度和冻融稳定性都有所增加。     

几种蜡质玉米变性淀粉的性质研究

比较了不同蜡质玉米变性淀粉的性质。重点考察了羟丙基蜡质玉米淀粉、己二酸醋酸酯淀粉和羟丙基己二酸醋酸酯淀粉的凝沉性、冻融稳定性、粘度、透明度、耐盐、耐酸性及淀粉糊的外观。     

微波法制备羟丙基玉米淀粉的研究

研究了微波作用下,淀粉乳质量分数、微波处理时间、微波的功率、环氧丙烷用量对羟丙基淀粉理化性质的影响,通过正交实验获得了制备羟丙基淀粉的最佳反应条件为:淀粉乳质量分数40%、环氧丙烷用量4.8%,微波作用时间90 s(每次作用10 s,间歇1 min)、微渡功率600 W,在该条件下制备的羟丙基淀粉的分子取代度为0.041,其冷水可溶性好、糊透明度高、热稳定性好、黏度大、冻融稳定性好.与常规方法相比,微波法制备羟丙基淀粉的反应时问大大缩短.     

羟丙基豌豆淀粉制备工艺及性质研究

以豌豆淀粉为原料,环氧丙烷、氢氧化钠分别为醚化剂和催化剂,对制备羟丙基淀粉的工艺和性质进行了研究。探讨了制备工艺中环氧丙烷、pH值、温度、时间对羟丙基取代度的影响;采用响应面法设计优化试验。得到最佳工艺条件为:环氧丙烷添加量12%、反应pH11.3、反应温度40℃、反应时间18h。结果表明:与原淀粉相比,制得的低取代度羟丙基淀粉糊化温度下降了11～18℃,峰值黏度增加了74%～109%;在34～90℃,溶胀度随取代度的增加而增加;同时,羟丙基化还降低了淀粉的消化性。     

辐照作用对羟丙基玉米淀粉取代度的影响

γ-射线辐照技术是一种新型的物理加工处理方法,目前将辐照技术用于淀粉改性的研究是一新热点。为此以玉米淀粉为原料,考察了辐照剂量、淀粉乳浓度、环氧丙烷用量、NaOH用量、Na2SO4用量、反应温度和反应时间对其羟丙基化的影响,并通过正交实验获得了辐照法制备羟丙基玉米淀粉的最优工艺条件为:辐照剂量为7 kGy、环氧丙烷用量12%、淀粉浓度为45%、NaOH用量为1.0%,在该条件下于45℃反应8 h制备的羟丙基玉米淀粉的摩尔取代度(MS)为0.27。     

羟丙基糯米淀粉的制备及其性质的研究

以糯米淀粉为原料制备羟丙基淀粉,考察了环氧丙烷用量、反应时间、反应温度、淀粉乳浓度、氢氧化钠、硫酸钠对淀粉取代度和反应效率的影响,并对不同取代度的羟丙基淀粉的性质进行了研究。实验结果表明,以上各因素对羟丙基淀粉的取代度都有明显的影响,而且不同取代度的羟丙基淀粉的透明度和冻融稳定性及表观黏度比原淀粉都有提高,但白度变化不明显。     

In vitro Digestibility of Hydroxypropylated and Cross-linked Waxy and Non-waxy Rice Starches

In vitro digestibility of hydroxypropylated and cross-linked waxy and non-waxy rice starches was investigated to find the proper resistant starch (RS) assaying method for chemically modified starches. RS and total dietary fiber (TDF) content of hydroxypropylated and cross-linked waxy and non-waxy rice starches were measured using the approved AOAC RS assay procedure (AOAC method 2002.02) and the AOAC TDF assay procedure (AOAC method 985.29). Hydroxypropylation did not alter the RS content of waxy and non-waxy rice starches (less than 1% of RS). Cross-linking also did not change the RS content of waxy and non-waxy rice starches (less than 1% of RS). It is interesting to note that non-RS content decreased with increasing hydroxypropylation (97-80%) and cross-linking (99-95%) in both waxy and non-waxy rice starches. This indicates that some fraction of RS in hydroxypropylated and cross-linked waxy and non-waxy rice starches cannot be measured using approved AOAC RS and TDF assay procedures. Therefore, the RS and TDF assay procedures performed in this study are not appropriate to determine the RS content of chemically modified starch. Further investigation is needed to develop a method to determine the RS content of chemically modified starch.     

Synthesis and Characterization of Hypochlorite Oxidized Starches

Egyptian rice and maize starches were treated with sodium hypochlorite at different concentrations. The oxidized starches so obtained were monitored for carboxyl content and rheological properties. In addition, the extent and rate of the oxidation reaction was assessed by investigating the chlorine consumption. Results indicated that the extent and rate of oxidation of rice starch, expressed as chlorine consumption, are much higher than those of maize starch. The opposite holds true for the carboxyl content. Pastes of rice and maize starches before and after oxidation exhibit non-Newtonian thixotropic behaviour but their apparent viscosity decreases by increasing the hypochlorite concentration. At any event, however, the apparent viscosity of rice starch is substantially higher than that of maize starch. Storing the pastes for 24 h adversely affect the apparent viscosity particularly with oxidized starches prepared using higher hypochlorite concentrations.     

Retrogradation Kinetics of Eight Starches

Retrogradation rate and extent were determined by differential scanning calorimetry and rheology measurements on 40% dry matter gels made from pea, modified waxy maize, rice, waxy rice, wheat, manioc, potato and microwaved irradiated potato starches. As a result, each starch retrogrades differently, depending also on the measurement technique. Nevertheless, potato and pea starches seem to be the most sensitive and the waxy and modified waxy types are the least sensitive to retrogradation.     

韧化处理对不同玉米淀粉理化特性的影响

以不同直/支链比例的普通玉米淀粉和蜡质玉米淀粉为材料,在40、50、60℃进行韧化处理,研究韧化处理对玉米淀粉理化特性的影响。结果表明：韧化处理的两种玉米淀粉颗粒形貌有较小变化。韧化处理后,两种淀粉的溶解度和膨胀度随着处理温度的升高而降低;所有韧化处理过的玉米淀粉黏度低于原淀粉,起糊温度高于原淀粉;韧化处理后淀粉的糊化温度升高,热焓变化不大。     

Characteristics of Imitation Cheese Containing Native Starches

ABSTRACT Imitation cheeses containing 3% native maize, waxy‐maize, wheat, potato or rice starch were manufactured and the microstructure, meltability, texture and dynamic rheology of these products were compared to a control (0% starch). Fat globules in starch‐containing products (except potato) were smaller than in the control as evidenced by electron microscopy. All starches reduced meltability and cohesiveness of the imitation cheeses. Hardness was increased by wheat, potato or maize starch but reduced by waxy‐maize or rice starch. Starches significantly reduced tan 8 peaks compared to the control with potato starch having the greatest effect. Rice starch appears to have the most potential as a partial casein substitute in imitation cheese.     

Effect of Modified Starches on Rheological Properties of Ketchup

The aim of this work was to study the effect of commercial modified starches of different origin on rheological properties of ketchup. The following starches were used to produce the ketchup samples: chemically modified potato (acetylated distarch adipate from potato starch), waxy maize (acetylated distarch adipate from waxy maize starch and hydroxypropyl distarch phosphate from waxy maize starch), and cassava (acetylated distarch adipate from cassava starch) starches and physically modified cassava and waxy maize starches (physically modified cassava starch and physically modified waxy maize starch). The SEM microphotographs revealed that swollen or disrupted starch granules were present in the ketchup samples. As was evaluated by particle size distribution analysis, two peaks characteristic for different starch granule sizes were observed, the first peak at about 100 μm for ketchup thickened with potato starch and the second one at about 50 μm for the rest of the samples. Ketchups showed non-Newtonian, shear-thinning flow with tendency to yield stress. Values of the rheological parameters describing the flow curves significantly correlated with Bostwick consistency. Ketchup samples exhibited different susceptibility for temperature changes, while values of flow activation energy were from 4.18 to 9.00 kJ/mol. On the basis of mechanical spectra, it is noted that values of G′ were higher than these of G″ showing that elastic properties dominated over the viscous ones. Ketchup samples exhibited properties of weak gels which were estimated from the values of G′ and G″ moduli and their relation and from values of tangent of phase angle (tan δ = 0.14???0.37). Principal component analysis revealed both similarities and differences in rheological behavior of the examined ketchup samples thickened with different modified starches.     

Pasting properties of hydroxypropylated starches before or after proteinase treatment

To examine the effect of starch protein on hydroxypropylation, corn (normal and waxy) and potato starches were hydroxypropylated with propylene oxide at two levels (8.3 and 12.3% based on dry basis of starch weight) before or after proteinase (thermolysin) treatment, and then pasting properties of the starches were measured. For normal corn starch, protein appeared to be involved in hydroxypropylation, especially at the higher concentration of reagent (12.3%); the starch hydroxypropylated after proteinase treatment (Enz‐HP) showed less reaction efficiency than that only hydroxypropylated (HP) or proteinase treated starch after hydroxypropylation (HP‐Enz). This suggests a possible reaction between some of the reagent and the starch proteins that exist in the channel and surface of the starch granules. However, not much difference was found with the waxy corn starch, as it contains much lower amounts of amylose and protein than normal corn starch. The potato starch, which has no channels, showed complicated protein effects. For potato starch, a different access of the enzyme and chemical reagents to the granule matrix could be possible.     

羟丙基糯玉米淀粉合成工艺及性能研究

本文以糯玉米淀粉为原料，以环氧丙烷为醚化剂、氢氧化钠为催化剂、硫酸钠为抑制膨胀剂，对糯玉米羟丙基淀粉合成工艺及其性能进行了研究，探讨了糯玉米淀粉乳浓度、环氧丙烷用量、反应时间、反应温度、氢氧化钠用量及硫酸钠用量对糯玉米羟丙基淀粉取代度和反应效率的影响。实验结果表明，增加环氧丙烷用量、延长反应时间，可使羟丙基淀粉取代度增加。对糯玉米羟丙基淀粉的冻融稳定性、透明度及粘度进行研究表明，随着羟丙基糯玉米淀粉取代度的增加，其冻融稳定性和透明度增加，但粘度却降低。     

Comparison of Thermal and Viscoelastic Properties of Four Waxy Starches and the Effect of Added Surfactant

The waxy starches used in this investigation (maize (WM), barley (WB) and two rice starches RD4 and IR29) showed different gelatinization temperatures (GT) and enthalpies (ΔH_G) measured with differential scanning calorimetry (DSC). The differences in GT and ΔH_G could only partially be related to X-ray crystallinity. The high GT waxy starches WM and RD4 retrograded to a greater extent measured with DSC and the order of increased retrogradation agreed well with the order of X-ray crystallinity of the retrograded waxy starches. The melting temperature (T_C) of the retrograded waxy starches in contrast to GT was very similar for all starches. This indicates that the temperature of the glass transition (T_g) of the amorphous regions in the starch granules controlled the onset GT and perhaps also the extent of retrogradation. Addition of cetyl trimethyl ammonium bromide (CTAB) decreased the extent of retrogradation more than 45% compared to the melting enthalpy (ΔH_C) of the waxy starches without CTAB addition. The rice starch RD4 was most affected by the CTAB addition, and the WM starch the least. The viscoelastic behaviour in the temperature interval 25–90°C of 12%(w/w) gels differed between the waxy starches. The WB starch gels showed the highest storage modulus (G′) value and the lowest phase angle (δ), i. e. strongest and least viscous gels. The WM starch gels showed the lowest G′ value and the highest δ. The rice starches were in between with the RC4 starch (high GT) showing higher G′ value and lower δ than the IR29 (low GT). The viscoelastic parameters changed only slightly with increased temperature. The addition of CTAB to the waxy starch gels changed the viscoelastic behaviour of the stronger and less viscous starch gels of the WB and RD4 as their G′ value decreased and δ increased with increased temperature. The effect on WM and IR29 was only small.