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Flour starch thermal characteristics
Modulated scanning calorimetric study
main source of starch in biscuit product is flour. Soft wheat flour is comprised of 74% starch, 9% protein, 2.5% fat, 0.5% ash, and 14% moisture. The heat capacity of a starch–water system above the glass transition does not reach the expected
potential use as reinforcing fillers in thermoplastics [ 8 ]. This study examined bio-composites with pineapple flour and destarched cassava flour from tropical crops to enhance the thermal and mechanical properties. In addition, the manufactured bio
) and plum puree and concentrate ( Sheikholeslami et al., 2018 ) for increasing nutritional value, delaying staleness and quality improvement may be the prime examples for these research efforts. The wheat variety and quality of flour are the most
) and plum puree and concentrate ( Sheikholeslami et al., 2018 ) for increasing nutritional value, delaying staleness and quality improvement may be the prime examples for these research efforts. The wheat variety and quality of flour are the most
chloride (PVC) [ 10 – 14 ]. Among these, the markets for wood flour-poly(vinyl chloride) composites (WF-PVC) are increasing dramatically, with a growth perspective of 200% from 2002 to 2010[ 1 ]. They are now typically used in building construction
Construction of a wheat-flour state diagram
Application to extrusion processing
We use pressure-variable differential scanning calorimetry to detect and characterize thermally induced transitions (glass, melting, gelatinization) in pre- and post-extruded wheat flour. The resulting data allow us to construct a two-dimensional state diagram which maps the physical states that pre- and post-extruded wheat flour can assume, at constant pressure, as a function of moisture content, temperature, and the specific mechanical energy, SME, generated in the extruder. We describe how this state diagram can be used to map the path of extrusion processing, to assess the impact of extrusion conditions, and, ultimately, to design formulations and processing conditions that result in desired end-product attributes. For the extrudates, we find that the extent of processing-induced fragmentation, as monitored by reductions in the extrudate glass transition temperature,T g, increases with the SME generated in the extruder. We demonstrate that a wheat-flour state diagram, which includes the glass curve of the wheat-flour extrudates produced at various SME values, allows one to predict and control the impact of processing conditions on extrudate properties.
–polymer adhesion, mixing time, and processing temperature [ 5 – 8 ]. Among these factors, fiber–fiber interactions as well as the fiber–matrix adhesion plays the most important role in transferring the stress from the matrix to the filler, wood flour (WF) has a
Abstract
Glass transition temperature of red crayfish flour (moisture 3.56%) was determined using a phase transition analyser (Wenger Technical Centre, USA). Due to the importance of physical ageing in functional properties of red crayfish flour (with 65% protein) the possible occurrence of physical ageing in dry powder of crayfish flour was studied at different temperatures below and close to the glass transition. Endothermic peaks that corresponded to relaxation enthalpy were observed for a commercial crayfish flour with 4.5% moisture. Enthalpy and peak temperature increased on storage of crayfish flour when it was held in the glassy-state at different temperatures (5, 15, 25°C).
Abstract
Isothermal crystallization and melting of isotactic polypropylene in binary polypropylene-wood flour composites has been studied by DSC, and the influence of an ethylene-methacrylic acid copolymer interfacial agent analyzed. Wood flour induces a slight nucleating effect, reducing the basal interfacial free energy of nucleation and increasing the overall crystallization rate. The interfacial agent generates a compatibilization phenomenon and an increase in the basal interfacial free energies with respect to the binary composites. In both binary and ternary systems the melting behaviour is a function of undercooling and is unaltered by the presence of either wood flour or the interfacial agent.
Summary In this study, the thermal properties of agro-flour-filled polybutylene succinate (PBS) bio-composites were investigated. PBS is one of the biodegradable polymers made from the condensation reaction of glycols and dicarboxylic acid and is naturally degraded by natural soil burial system. The thermal properties of the bio-composites were analyzed according to the agro-flour content and mesh size. On increasing agro-flour content, the thermal stability, degradation temperature and derivative thermogravimetric curve (DTGmax) temperature of the bio-composites decreased while the ash content increased. The thermal degradation of the bio-composites was not affected by agro-flour mesh size. The glass transition (T g) and melting (T m) temperatures of the bio-composites were not significantly changed. The storage modulus (E’) of the bio-composites was higher than that of neat PBS, because the incorporation of agro-flour increased the stiffness of the bio-composites. At higher temperatures, E’ of the bio-composites decreased due to the increasing viscosity and chain mobility of neat PBS. The thermal properties of bio-composites have an important effect on the manufacturing system and application methods.
