集水区土地利用监控模式

台湾省的土地资源非常有限,山地面积占73.65%,平地仅占26.35%,由於人口急速膨胀,大量向都市集中淤是都市范围不断扩张,使得广大山坡地成为重要开发之目标。本省山地约占2/3,因地形起伏大,加上降雨集中,一遇豪雨,雨水所汇集之迳流即流入溪流,迅速排出,无法渗透至地下,故集流时间短、洪峰流量大,成为台湾水文环境之特性。在资源有限,自然环境欠佳,而各种森林资源之开发、农地之利用、人口居住又面临迫切的需求下,如何兼顾资源的开发与保育,避免两者之间的冲突,集水区水资源的开发与划定亦是重要的课题之一。水里溪集水区位於台湾省中部,属浊水溪中游之水系,面积约7400hm²,包括明湖、明潭、日月潭等三个水库及钜工调整池。由於区内交通方便,游客众多,观光事业发达;另一方面,因本集水区的气候、土壤适宜栽种摈榔等经济作物,在有厚利可图的情况下,集水区内的土地纷纷改种槟榔,近年来更有大量种植的趋势,使得森林的覆盖减少,造成生态环境、微气候的改变,并对当地的水土冲蚀、水质、水量产生影响,故对於集水区的经营与管理,需有一合宜的监控模式。本集水区的环境日益恶化,究其原因乃为土地利用之改变,故本研究即利用遥测影像加以判释,了解其土地利？     

Effects of Oxido-Reductants on Rheological Properties of Wheat Flour Dough and Comparison with Some Characteristics of Extruded Noodles

The effects of oxido-reductants on the rheological properties of wheat flour dough were evaluated by using a capillary rheometer and an oscillatory rheometer at three temperatures. The oxidants potassium iodate (KIO₃) and l -ascorbic acid (l -AA) significantly increased the apparent viscosity and G′ and decreased loss tangent at low temperatures of 30 and 60°C due to enhanced formation of disulfide bonds. The reductant glutathione (GSH) had the opposite effect. Heating caused the gelatinization of starch, which diminished the effects of the oxido-reductants and produced doughs with similar rheological properties at 80°C. The correlation between dough rheology and characteristics of extruded noodles was also studied.     

Effect of Amylose Content on Expansion of Extruded Rice Pellet

Rice pellets were prepared by single‐screw extrusion cooking with an in‐barrel water content of 50 wt%. Three different types of rice, indica glutinous, japonica, and indica, were used as raw materials. Reconstituted rice flour was made to study the effect of amylose content on pellet expansion. The glass transition (T_g) and expansion (T_e) temperatures of extruded pellet were determined by differential scanning calorimetry (DSC) and noncontact infrared thermometer, respectively. The amylose content was not significantly affected by extrusion cooking. The reduction in intrinsic viscosity indicated that amylopectin experienced some degradation. The T_g and T_e were not functions of amylose content, which affected the expansion ratio of the pellets. The Gordon‐Taylor equation was applied to estimate the T_g of the rice pellets.     

Molecular and Gelatinization Properties of Rice Starches from IR24 and Sinandomeng Cultivars

The differences in pasting properties involving gelatinization and retrogradation of rice starches from IR24 and Sinandomeng cultivars during heating‐cooling processes were investigated using a Rapid Visco Analyser (RVA)and a dynamic rheometer. The results were discussed in relation to the molecular structure, actual amylose content (AC), and concentration of the starches. Generally, both starches possessed a comparable AC (≈11 wt%), amylose average chain length (CL), iodine absorption properties, and dynamic rheological parameters on heating to 95°C at 10 wt% and on cooling to 10°C at higher concentrations. In contrast to Sinandomeng, IR24 amylose had a greater proportion of high molecular weight species and number‐average degree of polymerization (DP_n). IR24 amylopectin possessed a lower DP_n and greater CL, exterior CL (ECL), and interior CL (ICL). Comparing the results of RVA analysis and dynamic rheology, the gelatinization properties and higher retrogradation tendencies of IR24 starch can be related to the structural properties and depend on starch concentration. In addition, the exponent n of starch concentration for storage moduli at 25°C (G′₂₅ ∝ Cⁿ) increased linearly with increasing AC.