Hyperbranched polyester polyol plasticized tapioca starch/low density polyethylene blends

ABSTRACT: In this work, low density polyethylene (LDPE)/plasticized starch (TPS) blends were prepared. The TPS employed in this study was obtained by plasticization of tapioca starch with a hyperbranched polyester polyol. Differential scanning calorimetry analysis showed that the melting temperature increased with the TPS content. The opposite effect was exhibited in the crystallization temperature and additional changes were not observed during the heating. X-ray diffraction analysis showed a reduction in intensity of the peak at Bragg’s angle 17.5°, proving a diminution on A type crystallinity with the increasing amount of LDPE. Micrographs obtained by scanning electron microscopy exhibited starch granules without destructure. TPS acted as a filler to LDPE, since the mechanical properties (Young’s modulus and tensile strength) improved ostensibly. The Young’ modulus and tensile strength decreased with the amount of LDPE, however, the elongation at break exhibited an opposite behavior

Extrusion of starch-based films and characterization of physico-mechanical, thermal and microstructural properties

The objectives of this dissertation work were to study the film-forming behavior of corn starch and to characterize the microstructure and functional properties of the films. The effects of glycerol, water, stearic acid and extrusion temperature on the film-forming attributes of corn starch and on selected physical and functional properties of starch films were analyzed. The tensile and water vapor properties (WVP) of starch films were significantly influenced by plasticizer content. The multiple glass transitions recorded in the thermoplastic starch were indicative of phase separation of starch into starch-rich and glycerol-rich domains. Similarly, the melting endotherms and presence of starch granules in films suggested that the starch granules were not melted completely during extrusion. Amylose-lipid complexes were formed during extrusion processing, depending on the moisture and stearic acid contents. Urea plasticized the starch more effectively than stearic acid and sucrose, and formed stable hydrogen bonds with starch. High-performance size exclusion chromatography data confirmed that both amylopectin and amylose were fragmented during extrusion, resulting in reductions in the amylopectin content and a consequential increase in the amylose content. However, the extent of fragmentation in the amylopectin and amylose chains was not on a logarithmic scale. Regression models predicting the relative percentages of amylose and amylopectin and their molecular weights in the thermoplastic starch were developed. Fourier-transform infrared spectra revealed interactions between the functional groups of starch and glycerol. The native \u27A\u27 type crystalline structure of starch was destroyed during extrusion. Aging studies demonstrated that the extruded amorphous starch developed \u27B\u27 and \u27V\u27 type crystalline polymorphs after just three days of storage. The tensile strengths of starch films increased progressively while both the tensile strains and WVP decreased continuously with respect to aging-time. Blending of low-density polyethylene (LDPE) into starch network improved the tensile strengths and strains of the films and decreased the WVP. Compounding of the ingredients before film-forming improved the dispersibility of starch and LDPE and the stress transfer between the two polymers

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Research findings based on student's PhD workDeep-fat frying (DFF) is the major processing step in preparation of pantoa, a popular Indian dairy sweetmeat. In this study, the dough for pantoa was rolled into balls of 15 g, and fried in sunflower oil at 125, 135 and 145 °C for 8 min. Convective heat transfer coefficient, which defines the heat transfer characteristics of the product during DFF, was determined using one-dimensional transient heat conduction equation as 92.71–332.92 W·m− 2·K− 1. Neurocomputing techniques such as connectionist models and adaptive neurofuzzy inference system (ANFIS) were compared vis-à-vis multiple linear regression (MLR) models for prediction of heat transfer coefficient. A back-propagation algorithm with Bayesian regularization optimization technique was employed to develop connectionist models while the ANFIS model was based on Sugeno-type fuzzy inference system. Both connectionist and ANFIS models exhibited superior prediction abilities than the classical MLR model. Amongst the three approaches, the hybrid ANFIS model with triangular membership function and frying time and temperature as input factors gave the best fit of convective heat transfer coefficient with R2 as high as 0.9984 (99.84% accuracy) and %RMS value of 0.1649.Not Availabl

Influence of circadian rhythm, breed, stage of lactation, milk yield and parity on body and udder skin surface temperature of lactating cows monitored by infrared thermography

ABSTRACTThe objective of the study was to establish baseline thermographic information on body and udder skin surface temperature (USST) of lactating cows in different stages of lactation, milk yield, parity, breed and season. Holstein Friesian crossbred (n = 19 cows) and Deoni lactating cows (n = 14 cows) were monitored for body (i.e. eye) and USST prior to milking using a forward looking infra-red (FLIR) camera. It was observed that the mean body and USST of both crossbred and Deoni cows did not differ significantly. The body and USST of both the breeds were significantly higher by 0.9–1.0°C during evening than morning milking. There was no difference in body and USST between days and between udder quarters. Similarly, stage of lactation, milk yield and parity did not show any influence over body and USST. The body and USST were higher in summer (1.1°C) than in spring and winter seasons. Deoni cows had 1.0°C lesser body and USST than crossbred cows. It is concluded that baseline thermographic information on body and USST would be useful in developing breed-specific thermographic signature for individual animal

Influence of moisture content on the flow properties of basundi mix

In this study, flow and flow-related properties namely morphology, angle of repose, moisture sorption, glass transition and sticky point temperature of basundi mix powder were determined. The bulk and tapped densities decreased from 690.71 to 622.71 kg/m3 and 819.10 to 729.31 kg/m3, respectively as moisture content increased from 3 to 9% (d.b.). Cohesiveness, expressed in terms of Hausner ratio and Carr index, increased with increase in moisture content. The sticky point temperature also decreased from about 40 °C at 2% moisture content to 10 °C at 8% moisture content, suggesting that the product was very much susceptible to caking. The basic flow energy values increased from 783.39 kPa at 3% moisture content to 1883.2 kPa at 9% moisture content. Shear tests showed that basundi mix was relatively more flowable at 3% (or less moisture content) than at 9% moisture content. It could be concluded that dynamic flow tests were better in characterizing flowability of basundi mix than static flow indicators such as angle of repose and Hausner ratio. Overall, basundi mix could be classified as a cohesive material, and to have better flowability and less stickiness, this powder is recommended to be stored at < 30 °C and 40% RH. This characterization will help to understand the behavior of basundi mix during processing, and will be useful in the design of handling, processing and storage equipment.by Hrishikesh Mitra, Heartwin A. Pushpadass, Magdaline Eljeeva Emerald Franklin, R.P. Kingsly Ambrose, Chinmay Ghoroi and Surendra Nath Battul