Dielectric properties of six different species of starch at 2450 MHz

Ndife, Matrid; Şumnu, Gülüm; Bayındırlı, Levent

doi:10.1016/s0963-9969(98)00058-1

Cited by 85 publications

(45 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Similar results were obtained by for corn starch solutions when the temperature was increased from 20°C to 80°C at a frequency of 10 MHz. In potato, wheat, corn, and waxy corn starch slurries (5-30% w/w) at 2.75 GHz (Ryynänen et al, 1996) and in wheat, tapioca, rice, corn, waxy corn and high-amylose starches at 2.45 GHz (Ndife et al, 1998), it was found that when the starch was already gelatinized, as in the present case, the mobility of water increased with temperature and heating caused a slight increase in the loss factor. Nelson et al (1991) also observed that the e 00 of different powdered hydrocolloids (potato starch, locust bean gum, gum arabic, carrageenan, and carboxymethyl cellulose) increased with temperature over the range from 20°C to 100°C.…”

Section: Dielectric Propertiessupporting

confidence: 68%

Optimización de la formulación de una salsa apta para calentar en microondas: estudio químico y microestructural

Expósito¹,

Miguel²

View full text Add to dashboard Cite

The microstructure and rheological properties of white sauces formulated with different starches were analyzed after being microwave-heated for different times. Significant differences (P < 0.05) in rheological parameters analyzed-storage modulus (G ), loss modulus (G ), and loss tangent (tan δ)-were obtained for sauces made with different starches. Microwave reheating did not affect G and G values until water evaporation became significant. In addition, tan δ values did not change significantly (P < 0.05) even during long reheating times showing that sauce viscoelastic properties did not change after microwave irradiation. However, microstructure assessed by confocal laser scanning microscopy showed changes in fat globule and protein. These microstructural changes did not seem to have a significant effect on rheological measurements since starch and ι-carrageenan are mainly responsible for the viscoelastic behavior of the sauces.Keywords: confocal laser scanning microscopy, microwave, rheology, starch, white sauce Practical Application: The development of products appropriate to microwave heating is constantly rising in food industry. It is necessary to understand the behavior of the ingredients and the final product to microwave heating in order to choose those ingredients which will develop the best performance. Starches are common ingredients in industrial sauces, and rheological and microstructural techniques have shown their usefulness in characterization of starch-based systems. IntroductionThe ready-to-eat meal sector has grown to currently become one of the most successful areas in food industry. This is mainly due to the new consumption habits characterized by an increased demand for products which are easy to prepare and consume and do not sacrifice sensory quality. In this context, microwave oven has become an indispensable appliance in every home due to its ease of use and quickness in preparing such foodstuff.Some commercial ready-to-eat products include sauces and dressings in their formulation. These liquid media are subjected to industrial processing in which heating and agitation stages lead to significant chemical and physical changes in raw ingredients until the final product is achieved. Moreover, these products withstand freezing or refrigeration conditions until they reach the final consumer. In order to maintain desirable appearance, texture, and stability throughout the product shelf life, these products usually have hydrocolloids and modified starches in their formulation (Sikora and others 2008;Mason 2009); moreover, the current demand for natural, clean-label foods has promoted the use of native starches (Arocas and others 2009a). These ingredients are able to bind water molecules forming a complex matrix in which interactions with other food components are crucial to understand product rheological and organoleptic behavior (Sikora and others 2008). MS 20110330 Submitted 3/15/2011, Accepted 7/2/2011 Authors Guardeño, Quiles, and Guardeño (E-mail: luiguaex@upvnet.upv .es...

show abstract

Section: Dielectric Propertiessupporting

confidence: 68%

Optimización de la formulación de una salsa apta para calentar en microondas: estudio químico y microestructural

Expósito¹,

Miguel²

View full text Add to dashboard Cite

show abstract

“…Afterwards, Tomasik et al [14] studied the effects of low-power (10 W; specific power not mentioned) microwave radiation on properties and structure of low-moisture content (14.5 %) potato starch. They mentioned a rapid drop in sample viscosity when it was treated with microwave for longer than 300 s. Lewandowicz et al [15] investigated potato and tapioca starch with 0.4 W g -1 specific incident microwave power and reported isothermal drying which affected the gelatinization temperature while Ndife et al [16] determined dielectric properties of six different species of starch in granular and solution form.…”

Section: Introductionmentioning

confidence: 99%

Vacuum Microwave Treatment of Potato Starch and the Resultant Modification of Properties

Mollekopf

Treppe

Fiala

et al. 2011

Chemie Ingenieur Technik

View full text Add to dashboard Cite

The study focuses on the vacuum microwave treatment of low-moisture potato starch. Typical temperature and drying profiles are presented and explained with the help of other process parameters such as sample weight, pressure, incident and absorbed microwave power. Subsequently water absorption capacity of vacuum microwave treated and conduction heated samples was investigated at 55°C. During vacuum microwave treatment, 50 g samples were treated with incident powers of 460, 500 and 750 W at 3800 Pa for durations between 30 and 300 s. Water absorption capacity increased exponentially with the net absorbed energy but could not be functionally correlated to end temperature and incident power. During conduction heating, starch samples were treated at temperature values of 120, 130, 140, 150 and 160°C, till constant weight.The water absorption capacity was observed to increase with increase in treatment temperature.

show abstract

“…20 Whereas, the relative permittivity of the starch is about 2-5. 21 According to the dielectric polarization theory, the BaTiO 3 particles that possess higher relative permittivity are strongly polarized under an electric field. The strong interactions between the polarized particles induce strong ER response.…”

mentioning

confidence: 99%

Mechanical and electrical properties of hydrous electrorheological elastomers based on gelatin/glycerin/water hybrid

Gao¹,

Zhao²

2007

J of Applied Polymer Sci

View full text Add to dashboard Cite

Aimed at improving the stability of geometrical shape, mechanical performance, and particles dispersion of electrorheological (ER) hydrous elastomers, a new gelatin water-based elastic gels containing starch particles were prepared under an applied dc electric field, and their ER effects were described with the compression modulus and the electric resistivity. The result demonstrates that the mechanical and electrical properties of the ER elastomers are dominated by an externally applied electric field as well as the weight fraction of particles. On comparing with the same chemical composition, elastomers cured without a field and with barium titanate/gelatin water-based elastomer, some conclusions are suggested: the object elastomer has stronger responses to a field than the same chemical composition elastomer, especially with higher weight fractions of particles. The object elastomer has steady geometrical shape and mechanical performance because of the addition of glycerin into the matrix, and has a better dispersion of particles.

show abstract

Dielectric properties of six different species of starch at 2450 MHz

Cited by 85 publications

References 8 publications

Optimización de la formulación de una salsa apta para calentar en microondas: estudio químico y microestructural

Optimización de la formulación de una salsa apta para calentar en microondas: estudio químico y microestructural

Vacuum Microwave Treatment of Potato Starch and the Resultant Modification of Properties

Mechanical and electrical properties of hydrous electrorheological elastomers based on gelatin/glycerin/water hybrid

Contact Info

Product

Resources

About