三氯氧磷交联马铃薯淀粉颗粒膨胀历程及溶胀机理研究

利用淀粉与三氯氧磷的交联反应 ,通过控制交联反应程度 ,成功地控制了交联淀粉颗粒的膨胀并使其停留在不同的溶胀阶段。本文详细地研究了处在不同溶胀阶段交联淀粉颗粒的结构特征和变化趋势 ,揭示了交联淀粉颗粒由高交联非糊化到低交联溶胀糊化的膨胀历程及溶胀机理 ,即交联马铃薯淀粉是以颗粒尾端为主的不均衡膨胀。     

三氯氧磷交联木薯淀粉颗粒膨胀历程及溶胀机理研究

利用木薯淀粉与三氯氧磷的交联反应,通过控制交联反应程度,成功地控制了交联淀粉颗粒的膨胀并使其停留在不同的溶胀阶段,详细地研究了处在不同溶胀阶段的三氯氧磷交联木薯淀粉颗粒的结构特征和变化趋势,揭示了三氯氧磷交联木薯淀粉颗粒的具体的膨胀历程及溶胀机理,即木薯淀粉是“花蕾绽放式”膨胀历程。     

三偏磷酸钠交联玉米淀粉颗粒膨胀历程及结构特征

利用淀粉与三偏磷酸钠的交联反应,通过控制交联反应程度,成功地控制了交联淀粉颗粒膨胀程度并使其停留在不同的溶胀阶段,详细研究了处在不同溶胀阶段交联淀粉颗粒的结构特征和变化趋势,揭示了三偏磷酸钠交联玉米淀粉颗粒的膨胀历程及结构特征,即随着淀粉颗粒交联程度的降低,颗粒的膨胀历程由中心脐点处爆裂膨胀方式转化为颗粒整体向外的均匀膨胀方式.     

三偏磷酸钠高交联玉米淀粉非糊化特征研究

研究了以三偏磷酸钠为交联剂制备非糊化的高交联玉米淀粉的方法，测定了反应的取代度和布拉班德粘度曲线，提出高交联玉米淀粉与原淀粉颗粒不同，在沸水只发生轻微溶胀，呈非糊化颗粒态。     

高交联马铃薯淀粉非糊化特性研究

研究了以三氯氧磷为交联剂制备非糊化的高交联马铃薯淀粉的方法，测定了反应的取代度和布拉班德粘度曲线，研究了在沸水中受热后非糊化淀粉的颗粒形貌及粒度分布等特性。提出高交联非糊化马铃薯淀粉存在着不同于原淀粉颗粒的沸水中只发生轻度有限溶胀的非糊化颗粒态。     

三偏磷酸钠高交联马铃薯淀粉非糊化特征研究

研究了以三偏磷酸钠为交联剂制备非糊化的高交联马铃薯淀粉的方法;测定了反应的取代度和布拉班德粘度曲线,提出高交联马铃薯淀粉与原淀粉颗粒不同,在沸水中只发生轻微溶胀,呈非糊化颗粒态。     

高交联木薯淀粉非糊化特征研究

研究了以三偏磷酸钠为交联剂制备非糊化的高交联木薯淀粉的方法,测定了反应的取代度和布拉班德粘度曲线,提出高交联木薯淀粉与原淀粉颗粒不同,在沸水中只发生轻微溶胀,呈非糊化颗粒态。     

高交联木薯淀粉的非糊化特性

以三氯氧磷为交联剂制备非糊化的高交联木薯淀粉,并测定了反应的取代度和布拉班德粘度曲线,研究了在沸水中受热后非糊化淀粉的颗粒形貌及粒度分布等特性．提出高交联非糊化木薯淀粉存在着不同于原淀粉颗粒的在沸水中只发生轻度有限溶胀的非糊化颗粒态     

淀粉颗粒粒径对淀粉交联程度影响的研究

本文通过改变淀粉颗粒的粒径来研究淀粉的交联。交联程度高的淀粉，溶胀度低，在同温度下黏度低。通过测定交联淀粉的黏度与溶胀度发现：淀粉的交联难易程度的大小随着淀粉颗粒粒径的变化而变化，在一定范围内，淀粉颗粒粒径越大，淀粉越易发生交联反应，同一交联条件下越易形成交联程度高的淀粉。     

稻米淀粉的糊化动力学研究

采用一级反应模型对不同类型稻米淀粉的糊化特性和糊化动力学进行了研究，结果表明：不同类型稻米淀粉的糊化特性有较大差异。淀粉的糊化能耗主要用于淀粉晶体的熔解，颗粒的膨胀和直链淀粉分子从淀粉颗粒中的脱离。其中以晶体崩解速度最大，所需能耗最小；其次为颗粒膨胀能，直链淀粉溶出的速度最小，所需能耗最大。不同来源淀粉的膨胀速度和直链淀粉溶解速度，糊化能及其分配也有所差异，以籼稻的润胀能较小，其次依次为粳稻和糯稻；籼稻直链淀粉脱离淀粉颗粒（淀粉糊上清液BV值）所需能耗最大，其次为粳稻。3种稻米淀粉的酶解能耗差异不大，以糯稻淀粉较难以水解。     

Structure-viscosity relationships for starches from different rice varieties during heating

The effects of starch particle size and leached amylose on the viscosity of rice starch dispersions and changes of short-range structure and amylose content in starch granules of different rice varieties during heating were investigated. It was found that starch granule swelling increased rice starch dispersion viscosity during heating. The viscosities of the starch dispersions during heating were principally dependent on granular volume fraction and independent of starch variety. A distinct correlation between the amount of leached amylose and swelling of starch granules was also found. High initial amylose concentrations in starch granules reduced swelling during heating, thereby reducing rice dispersion viscosities. Fourier-transform IR spectroscopy indicated that the loss of short-range order was significant when the temperature reached the pasting onset temperature. The short-range order of waxy and medium grain rice starches was higher than that of long grain rice starches before gelatinization. The loss of order of waxy and medium grain rice starches was greater than that of long grain rice starches during heating, which was due to the presence of amylose, restraining the swelling and disruption of starch granules during heating.     

Changes in Starch Granules Trapped and Heated Using Optical Tweezers

A microscopic method to investigate the swelling process of individual starch granules heated in excess water is proposed. A starch granule focused under a light microscope is adjustably trapped using the optical tweezing of a near-infrared laser beam, which simultaneously heats the granule. Using this method, morphological changes in starch granules during heating were continuously recorded and quantitatively analyzed by image-processing techniques. The changes in granules of domestic wheat starches with differing amylose content were investigated under irradiation by the laser beam at constant optical power. The shapes of swollen granules of waxy wheat starches were observed to be distinctly different from those of non-waxy starches. Numerical indicators, specifically the time constant of swelling for the granule and its swelling magnification, were also obtained. These showed little relation to the pasting profiles of the same starches, obtained with a Rapid Visco Analyser.     

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.     

Physicochemical, crystallinity, pasting and morphological properties of bean starch oxidised by different concentrations of sodium hypochlorite

The effect of bean starch oxidation at different active chlorine concentrations (0.5%, 1.0% and 1.5%) on the physicochemical, crystallinity, pasting and morphological properties of starch was investigated. The carbonyl content, carboxyl content, starch colour, swelling power, solubility, gel hardness, X-ray crystallinity, pasting properties, gelatinisation characteristics and morphology of the starches were evaluated. The bean starch oxidised with 0.5% active chlorine had the characteristic of a slightly crosslinked starch. As compared to the native and 0.5% active chlorine-oxidised starches, active chlorine at 1.0% and 1.5% increased the carbonyl content, carboxyl content and solubility of the starches. Moreover, these concentrations of active chlorine decreased the swelling power, gel hardness, relative crystallinity, breakdown, peak viscosity and setback, as compared to the native and 0.5% active chlorine-oxidised starches. The starch granules oxidised with 1.5% active chlorine had imperfections in their structure, and its surface appears to be rougher than the other granules.     

Physicochemical Properties of Field Pea, Pinto and Navy Bean Starches

Legume starches were compared for physicochemical properties that may explain differences in functional properties. Field pea starch had higher amylose, greater swelling power and solubility, and lower pasting temperatures than pinto and navy bean starches. Scanning electron microscopy (SEM) showed that field pea starch had larger, more irregularly shaped granules and more broken large granules than pinto or navy starches. The most starch damage was observed for field pea. Pinto and navy bean starches had greater resistance to swelling at 60°C than field pea indicating a more strongly bonded micellar network. Higher cold paste viscosity was observed for navy bean and field pea.     

Investigations on starches from major starch crops grown in Ghana: II.—Swelling and solubility patterns: Amyloclastic susceptibility

The patterns of progressive swelling and solubilisation of various starches from major Ghanaian starch crops have been evaluated over the range of pasting temperatures to provide evidence of the associative bonding (i.e. hydrogen bonding) within the granules. The swelling patterns were greatly influenced by the species of the starch tested, but all the starches, except those of maize and cocoyam (Xanthosoma sagittifolium), exhibited a single-stage swelling, reflecting the presence of one set of internal bonding forces. The dissolving action of amylases on granular starches, which provides another means for studying granule structure, was examined by measuring the starch degradation at different enzyme concentration levels and fixed amount of substrate. There was considerable variation in resistance to enzyme action among the starches. With ‘root’ starches, the resistance increased in parallel with increasing size of the granules.     

RELATIONSHIP BETWEEN PHYSICOCHEMICAL PROPERTIES OF STARCHES AND EXPANSION OF FISH CRACKER 'KEROPOK'

The influence of physicochemical properties of starches on expansion of‘keropok’was studied. Swelling power, solubility, and amylose leaching of a starch were dependent on the lipid and protein contents of the starch. The morphology of different starch granules used in‘keropok’gel was observed using scanning electron microscopy. The sizes of swollen starch granules in the gel were quantitatively measured by image analysis. The average length and width of swollen gelatinized sago and tapioca starch granules were significantly higher than that of wheat starch, and consequently, the linear expansion of‘keropok’with wheat starch was lower than those of‘keropok’made with tapioca or sago starches. Linear expansion was positively correlated to swelling power and solubility of the starch. Textural properties of‘keropok’gels with different starches were also measured and found to have correlation with linear expansion of the final products.     

Effect of Acetylation on Some Properties of Corn and Potato Starches

Corn starch and starches separated from different potato cultivars were acetylated to evaluate the effect of plant source on the physicochemical, morphological, thermal, rheological, textural and retrogradation properties of the starches. Corn starch showed a lower degree of acetylation than potato starches under similar experimental conditions. The degree of acetylation for different potato starches also differed significantly. Morphological examination revealed that the granules of acetylated Kufri Chandermukhi and Kufri Sindhuri starches tended to appear as fused and less smooth than native starch granules. Acetylation of corn and potato starches decreased the transition temperatures and enthalpy of gelatinization and increased swelling power and light transmittance. However, the change in these was greater in the potato starches with higher percentage of small sized granules. Acetylated starches showed higher peak G', G'' and lower tan δ than their counterpart native starches during heating. Among the starches from different cultivars, the change in the rheological parameters after acetylation differed to a significant extent. The retrogradation was observed to be negligible in the acetylated cooked starch pastes. Results implied that the change in functional properties of starches with acetylation depends on source and granule morphology of native starch.