削皮、水洗和干燥温度对木薯淀粉纯度和淀粉糊化粘度的影响

木薯在热带地区是碳水化合物的主要来源。木薯淀粉的品质受许多因素的影响。本项研究着重探讨淀粉提取过程中，削皮、水洗、干燥温度对淀粉纯度、白度和淀粉糊化粘度的影响。结果表明，未削皮的淀粉样品色发灰，但具有比削皮处理高的峰值粘度、95℃最后粘度、50℃时粘度、峰值降和持久性。增加水洗次数，不但能增加淀粉纯度，还可提高淀粉高峰值粘度、95℃最后粘度、50℃时粘度、持久性和糊化温度。不同干燥温度对淀粉白度无影响，但淀粉纯度随干燥温度的提高而稍稍增加。通常高的干燥温度有高的峰值粘度、95℃最后粘度、峰值降、50℃时粘度和持久性。     

Physicochemical and Pharmaceutical Properties of Carboxymethyl Rice Starches Modified from Native Starches with Different Amylose Content

Carboxymethyl rice starches (CMRS) were prepared from nine strains of native rice starches with amylose contents of 14.7–29.1%. The reaction was conducted at 50°C for 120 min using monochloroacetic acid as a reagent under alkaline conditions and 1-propanol as a solvent. After determining the degree of substitution (DS), the physicochemical properties including water solubility, pH, and viscosity of 1% (w/v) solution, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analyses of the granules, as well as some pharmaceutical properties of CMRS powders and pastes were investigated. The DS range was 0.25–0.40. All CMRS dissolved in unheated water and formed viscous gel. A good positive correlation was observed between amylose content and DS (r = 0.9278) but not viscosity. SEM and XRD concurrently revealed significant physical alteration of CMRS granules compared with those of native starches, which reflected the changes in the properties of CMRS. At 3% (w/w), CMRS can function as tablet binder in the wet granulation of both water-soluble and water-insoluble diluents. The tablets compressed from these granules showed good hardness with fewer capping problems compared with those prepared using the pregelatinized native rice starch as a binder. In addition, most CMRS pastes formed clear films with varying film characteristics, depending upon the amylose content of the native starches. This type of modified rice starch can potentially be employed as a tablet binder and film-former for pharmaceutical dosage formulations.     

Environmental conditions during root development: Drought constraint on cassava starch quality

Cassava has the reputation of being a drought tolerant crop, however, when deprived of water, plant and root development are affected. This ultimately will translate to an altered starch synthesis expressed by variation of starch quality. The magnitude of which, is influenced by the severity of stress conditions and stage of plant maturity. During early plant development,water stress retards growth, which will only be resumed after the immature plant has received sufficient water. Despite of an increased starch yield, the effect of initial water stress on starch quality is still sustained. In mature plants, starch quality is affected by environmental conditions prior to root harvest, especially the onset of rain after a stress period as indicated by a reduced starch paste. This paper presents the argument for extending the scope of traditional breeding programs beyond selecting for plant growth under drought conditions, to strategies that place greater emphasis on stabilizing starch quality. This revised version was published online in July 2006 with corrections to the Cover Date.     

Influence of amylopectin structure and amylose content on the gelling properties of five cultivars of cassava starches

Five cassava genotypes were investigated to identify the fine amylopectin structures and granule chemical compositions, which differentiated the starches into high (T(o) = 63.7 degrees C on average) and low (57.3 degrees C on average) gelatinization temperatures. The amylose contents (15.9-22.4%) and granular dimensions (12.9-17.2 microm) significantly differed among the starches. Diverse amylopectin structural elements resulted in significant swelling power, viscoelastic properties, and gel firmness. Debranched starches revealed a trimodal amylopectin distribution of three fractions: FIII (DP 12), FII (DP 24.31), and FI (DP 63) and FIII (DP 12), FII (DP 24.69), and FI (DP 67) for the low and high gelatinization starch groups, respectively. The higher proportion of FI long chain entanglement with amylose chain lengths to form longer helical structures was confirmed in the high gelatinization starch group, which developed "true" gels with better shear resistance, frequency independence, and higher gel firmness. Significant amounts of resistant starch fractions revealed the potential for application of these genotype starches in diverse foods.     

Border crossing of Muslim women in southern‐border provinces of Thailand

In general, the main roles of married Thai Muslim women were as home makers good wives and good mothers. Nevertheless, both married and single women from rural areas have been increasingly obliged to work outside the household, locally and in other countries. People in rural areas are now faced with the difficulty of maintaining their livelihoods if they depended on agricultural production alone. In some instances, female migration might be a response to families not being able to survive on the incomes earned by the male household heads. In response, women in southern Thailand provinces use long‐standing social networks that facilitate their migration for work, because they benefit from the close proximity, language, and religion that they share with the destination area. Commonly, they travel to work in Malaysia by using a border pass, while some travel and work without any documents. The effects of crossing national borders on migrants themselves and on their communities are mixed, generally positive from an economic perspective, but negative from a social viewpoint. Socially negative responses reflect a system of social control in the region based on patriarchy.