SIFAT PASTA PATI MILLET (Pennisetum glaucum (L.) R. Br.) TERMODIFIKASI HEAT MOISTURE TREATMENT UNTUK PEMBUATAN SOHUN

Improve the consumption of millet to vermicelli promoted for food diversification. Millet starch less stable of stirring and heating. Starch modification can improve the quality. In this research to evaluate pasting character of millet starch modified by heat moisture treatment which suitable for vermicelli. Heat moisture treatment conditioned at 25% moisture content and heating 100, 130 and 150 0C for 3, 5 and 7 hours with oven. Crystalline and starch paste properties of modified starch were analyzed and then selected to vermicelli. The suitable starch for vermicelli which stable paste of stirring and heating and high gel strength. The results show modified starch with 100 °C for 7 hours has an ideal for vermicelli. Shown by lower peak viscosity and viscosity breakdown (2951 cP and 71 cP), high final viscosity (3695 cP).Keyword : Heat moisture treatment, millet starch, RVA, pasting properties

Effects of micronized-roasted coffee concentration and temperature process on technological properties of rice-based extruded

New ingredients have been used in extruded products to increase the healthiness and regionalization of these products. However, the process variables that can interfere with the technological quality of the product should be studied, aimed at good acceptance by consumers. This study aimed to evaluate the effects of the concentration of micronized roasted coffee (MRC) and the barrel temperature on the technological properties of rice-based extrudates. The extrudates were made with 3 and 8% MRC to replace rice flour and processed in a mono-extruder at 140 and 180 oC. They were characterized for color, expansion index, hardness, bowl-life, porosity, water absorption index, and solubility index, and paste properties. To assess the effects of the process variables, analysis of variance, and Scott-Knott test (p <0.05) were applied to compare the means. The increase in MRC concentration reduced the color parameters and hardness, while the increase in temperature affected the expansion index. A joint effect of the variables concentration and temperature was observed for the other properties evaluated. The study showed that MRC is a potential source of fibers and natural pigments, with a direct effect on the main technological properties of the final product.

Effect of Extrusion on the Crystalline Structure of Starch during RS5 Formation

Amylose is well known to be organized helically with six glucose per turn, allowing it to form complexes with various ligands. This interaction can be affected by the type of crystalline structure present in the starch sources. This study evaluated the effect of extrusion on the crystalline structure of starch during RS5 formation. Rice and potato starches were extruded at 100 °C and 15 rpm with 5% and 10% oleic acid (OA), then the physical, thermal, paste properties, and resistant starch content (RS) were evaluated. Potato starch extruded with 10% OA showed granules embedded in a gelatinized starch matrix. The X-ray revealed that rice (orthorhombic) and potato (hexagonal) structures remain unchanged even after extrusion. Differential scanning calorimetry (DSC) evidenced the formation of type IIa amylose-lipid complexes in OA treatments, where potato extruded with 10% OA had the highest enthalpy (0.9 J/g). Moreover, the extruded potato showed the highest pasting temperature (87.19 °C), supporting the complex formation. The RS was reduced from 15.8 (isolated) to 4.14 mg/100 mg (extruded 10% OA) in rice. For potato, RS decreased from 17 to 13 mg/100 mg (isolated and extruded 10% OA). Overall, these findings suggest a tendency in potato starch (ortho-rhombic) to interact with OA during the extrusion process, promoting a crystalline lamellae growth when extruded with 10% OA; therefore, changing their properties.

Influence of internal sulfate attack on cement paste properties: contamination by pyrite

abstract: The objective of this work was to evaluate the influence of the presence of sulfate in the microstructure and compressive strength of cement pastes. The lack of availability of more suitable aggregates, for reasons of distance or costs, sometimes leads to the use of materials that contain sulfate in their composition, which is harmful to cement mixtures. Currently, there are normative recommendations that limit the content of contaminants in the aggregates. However, there are still divergences as to the content that does not damage the concrete. In order to discuss the levels presented in the standards and the values above those allowed by them, tests were carried out on cementitious compounds contaminated by pyrite in different levels of sulfates (0.0%, 0.5%, 1.0% and 5.0% of SO3). SEM, XRD, compressive strength, ultrasonic pulse velocity and porosity analyses were performed in samples at different ages until 720 days of age. During early ages until the first year, the most contaminated samples presented an increase in their strength (1.0% and 5.0% of SO3). This behavior was explained by SEM, XRD and porosity analyses by filling the pores with products of sulfate attack, such as ettringite. At the end of the tests (720 days) the series that presented the lowest compressive strength, the presence of cracks and large amounts of ettringite was the one that had 5.0% SO3 contamination, proving the importance of a normative limit content.