Photoacoustic measurements of thermal diffusivity of amylose, amylopectin and starch

Rodríguez, P.; Cruz, G. González de la

doi:10.1016/s0260-8774(02)00343-6

Cited by 18 publications

(11 citation statements)

References 11 publications

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“…The increase in the thermal diffusivity of SCFX extrudates due to void fraction increase could be explained by thermal diffusivity difference between air and solid materials including starch, whey protein and water. Provided the thermal diffusivity for air (2.16 × 10 -5 m 2 /s) reported by Shen et al [31] is two order of magnitude higher than the value of starch (2.0 × 10 −7 m 2 /s) reported by Rodriguez et al [32] more air in the foam will increase the thermal diffusivity of the product. Tomas et al [33] reported that the thermal diffusivity of whey protein concentrate (WPC-80) film was 0.71 × 10 −7 m 2 /s, which is close to that of starch.…”

Section: Resultsmentioning

confidence: 76%

Thermal Properties of Starch-Based Biodegradable Foams Produced Using Supercritical Fluid Extrusion (SCFX)

Mariam

Cho

Rizvi

2008

International Journal of Food Properties

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Starch-based extruded foams are in demand for many industrial applications because starch is biodegradable, inexpensive, and readily available in abundant quantity. In this study, the production of starch-based extruded foams using supercritical fluid extrusion (SCFX) having thermal properties such as heat capacity, thermal conductivity and thermal diffusivity comparable to commercial products have been reported. Pregelatinized corn starch was extruded with different concentrations of whey protein isolate (WPI) (0, 12, and 18 wt. %) with supercritical CO 2 (SC-CO 2) injection rates of 0.0, 0.4, 0.8, and 1.2 wt%. It was possible to vary the expansion and the density of SCFX extrudates by manipulating WPI concentration and SC-CO 2 injection rate. It was observed that the heat capacity, thermal conductivity and thermal diffusivity of starch-based SCFX extrudates were strong functions of their void fraction. The SCFX system is a useful tool for production of starchbased biodegradable foams, which do not require any organic solvents and are environmentally friendly and sustainable.

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Section: Resultsmentioning

confidence: 76%

Thermal Properties of Starch-Based Biodegradable Foams Produced Using Supercritical Fluid Extrusion (SCFX)

Mariam

Cho

Rizvi

2008

International Journal of Food Properties

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“…Ring, 1987;Conde-Petit et al, 1998;odr guez Gonz lez de la Cruz, 2003). When starch is dispersed in water or dimethyl sulfoxide (DMSO) (Killion & Foster, 1960), AM can be separated from AP by complex forming agents (Takeda et al, 1986;Takeda & Susumu, 1987;Charoenkul et al, 2006;Naguleswaran et al, 2013).…”

Section: Starch Fractionation Via Complex Formationmentioning

confidence: 99%

Methodologies for producing amylose: A review

Doblado-Maldonado

Gomand

Goderis

et al. 2015

Critical Reviews in Food Science and Nutrition

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Three main in vitro approaches can be distinguished for obtaining amylose (AM): enzymatic synthesis, AM leaching, and AM complexation following starch dispersion. The first uses α-d-glucose-1-phosphate (G1P), a glucosyl primer with a degree of polymerization (DP) of at least 4 and phosphorylase (EC 2.4.1.1), commonly from potatoes. Such approach provides AM chains with low polydispersity, the average DP of which can be manipulated by varying the reaction time and the ratio between G1P, primer, and enzyme dose. AM leaching is the result of heating a starch suspension above the gelatinization temperature. This approach allows isolating AM on large scale. The AM DP, yield, and purity depend on the heating rate, leaching temperature, shear forces and botanical origin. High leaching temperatures (80-85°C) result in mostly pure AM of DP >1000. At higher temperatures, lower purity AM is obtained due to amylopectin leaching. Annealing as pretreatment and ultracentrifugation or repetitive organic solvent-based precipitations after leaching are strategies, which improve the purity of AM extracts. When AM is separated by complex formation, complete dispersion of starch is followed by bringing AM into contact with, e.g., n-butanol or thymol. The resultant complex is separated from amylopectin as a precipitate. Complete starch dispersion without degradation is critical for obtaining AM of high purity. Finally, higher DP AM can be converted enzymatically into AM fractions of lower DP.

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“…Whereas density of slurries is useful for designing transport operations, specific heat capacity, thermal conductivity, and thermal diffusivity play an important role in the design of heat transfer processes. In addition to the basic information for flow design, the knowledge of density and thermal properties is necessary to model processes involving heat, momentum, and mass transfer in heterogeneous systems such as acid slurries of cassava bagasse 21 . According to Samaniuk et al, 22 much of the cost involved in the biomass pretreatment is related to the energy needed to warm up and cool down the biomass flows.…”

Section: Introductionmentioning

confidence: 99%

Thermophysical properties of dilute acid slurries of cassava bagasse as a function of biomass loading, acid concentration, and temperature

Polachini

Mulet

Cárcel

et al. 2020

Env Prog and Sustain Energy

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For suitable design of equipment and process optimization, the determination of thermophysical properties of the raw materials is necessary. Therefore, this work was aimed at determining and modeling the density, specific heat, thermal diffusivity, and thermal conductivity of acid slurries of cassava bagasse used during its conversion into bioethanol. Experimental measurements were carried out in slurries with different mass fractions of cassava bagasse (0.00 to 0.10) and phosphoric acid (0.00 to 0.10) at temperatures from 278.13 to 318.13 K. Results obtained show that density varied from 986.5 to 1,029.3 kg∙m−3, specific heat from 3,830.0 to 4,142.6 J∙kg−1∙K−1, thermal diffusivity from 0.9624 × 10−7 to 1.5249 × 10−7 m2∙s−1 and thermal conductivity from 0.3825 to 0.6212 W∙m−1∙K−1. While density increased with increasing solids and acid content at decreasing temperature, the thermal properties decreased at higher solids and acid content and increased when heating the slurries. The values were well‐fitted to polynomial models with good accuracy (R2 > 0.921 and MRE < 1.75%), allowing the application of the models to obtain reliable and ready‐to‐use data for cassava bagasse processing. Thus, the data reported in this study can be used for designing and managing momentum, heat and mass transfer processes for enhancing bioethanol production from cassava bagasse.

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Photoacoustic measurements of thermal diffusivity of amylose, amylopectin and starch

Cited by 18 publications

References 11 publications

Thermal Properties of Starch-Based Biodegradable Foams Produced Using Supercritical Fluid Extrusion (SCFX)

Thermal Properties of Starch-Based Biodegradable Foams Produced Using Supercritical Fluid Extrusion (SCFX)

Methodologies for producing amylose: A review

Thermophysical properties of dilute acid slurries of cassava bagasse as a function of biomass loading, acid concentration, and temperature

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