ABSTRACT:The effects of polyethylene-grafted maleic anhydride (PE-g-MA) on the thermal properties, morphology, and tensile properties of blends of low-density polyethylene (LDPE) and corn starch were studied with a differential scanning calorimeter (DSC), scanning electron microscope (SEM), and Instron Universal Testing Machine, respectively. Corn starch-LDPE blends with different starch content and with or without the addition of PE-g-MA were prepared with a lab-scale twin-screw extruder. The crystallization temperature of LDPE-corn starch-PE-g-MA blends was similar to that of pure LDPE but higher than that of LDPE-corn starch blends. The interfacial properties between corn starch and LDPE were improved after PE-g-MA addition, as evidenced by the structure morphology revealed by SEM. The tensile strength and elongation at break of corn starch-LDPE-PE-g-MA blends were greater than those of LDPE-corn starch blends, and their differences became more pronounced at higher starch contents.

ABSTRACT:The effects of glycerol and polyethylenegrafted maleic anhydride (PE-g-MA) on the morphology, thermal properties, and tensile properties of low-density polyethylene (LDPE) and rice starch blends were studied by scanning electron microscopy (SEM), differential scanning calorimetry, and the Instron Universal Testing Machine, respectively. Blends of LDPE/rice starch, LDPE/rice starch/ glycerol, and LDPE/rice starch/glycerol/PE-g-MA with different starch contents were prepared by using a laboratory scale twin-screw extruder. The distribution of rice starch in LDPE matrix became homogenous after the addition of glycerol. The interfacial adhesion between rice starch and LDPE was improved by the addition of PE-g-MA as demonstrated by SEM. The crystallization temperatures of LDPE/rice starch/glycerol blends and LDPE/rice starch/glycerol/PEg-MA blends were similar to that of pure LDPE but higher than that of LDPE/rice starch blends. Both the tensile strength and the elongation at break followed the order of rice starch/LDPE/glycerol/PE-g-MA blends Ͼ rice starch/ LDPE/glycerol Ͼ LDPE/rice starch blends. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 344 -350, 2004

Cereal Chem. 75(3):380-385A digital image analysis method was developed to quickly and accurately measure the degree of milling (DOM) of rice. The digital image analysis method was statistically compared to a chemical analysis method for evaluating DOM, which consisted of measuring the surface lipids concentration (SLC) of milled rice. The surface lipid area percentage (SLAP) obtained by the image analysis method and the SLC obtained by chemical analysis had a high coefficient of determination using a quadratic model (R 2 = 0.9819) and using a logarithmic model (R 2 = 0.9703). The quadratic model and the logarithmic model were validated using the test data set and it received high coefficients of determination (R 2 = 0.9502 and R 2 = 0.9459, respectively).Rice millers grade rice quality for nutritional and economic considerations and, thus, need a fast and accurate grading system as part of their milling assessment operations. The primary physical grading factors are head rice yield, which is the weight percentage of rough rice remaining as head rice (kernels that are 75% or more of their original length after milling), and degree of milling (DOM), which indicates how much bran remains on milled kernels (USDA 1979). Generally, milled rice with a high DOM level has less kernel bran than does milled rice with low DOM levels. The current methods for grading rice quality are subjective and time-consuming. This study developed a digital image analysis method that can quickly and accurately determine DOM.DOM is an important factor in terms of the nutritional value and the economic return of the milled rice. Low DOM level rice contains more protein, vitamins, minerals, and lipids than does high DOM rice (Wadsworth et al 1991). Although low DOM level rice has greater nutritional value, it often has a lower market appeal because most consumers prefer the taste and appearance of well-milled rice. Additionally, the degree to which rice is milled inversely affects head rice yield (Sun and Siebenmorgen 1993). Therefore, adjusting DOM during the rice milling operations is essential for optimizing quality and economic return. DOM can be measured by several methods, including visual inspection, chemical analysis, and optical measurements. Traditionally, DOM has been determined through visual inspection by trained personnel. For official grading, this judgment is made by comparing a sample to one of four official samples representing the four DOM grades (undermilled, lightly milled, reasonably well-milled, and well-milled) defined by the United States Standards for Milled Rice (USDA 1979). The closest similarity between the official representative sample and the inspection sample determines the DOM grade. Visual inspection is not only subjective but also is lacking in terms of quantitatively assessing the milling degree. For accurate measurement, more objective and quantitative methods must be employed to determine DOM.Chemical methods of assessing DOM include the differential dye-staining procedure and the compositional analysis...