The effect of moisture content on the crystallinity and glass transition temperature of inulin

Zimeri, J.E; Kokini, Jozef L.

doi:10.1016/s0144-8617(01)00260-0

Cited by 108 publications

(42 citation statements)

References 24 publications

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“…However, the shift in the glass transition temperature of the wet resin system shows a confinement effect as discussed by Arndt et al 47 for salol relaxation dynamics in nanometer size pores; the relaxation rate of the confined material increased compared to bulk material. Some other examples of observed low T g with moisture/ water content can be found in the literature, 10,11,48 where change in the glass temperature was reported for inulin, epoxy resins and cellulose. The epoxy system studied 11 showed that the glass transition estimated from the mechanical modulus shifted to lower temperatures with different moisture treatment with shift related to the moisture weight gain, which we have not included in this work.…”

Section: Dielectric Relaxation Mapmentioning

confidence: 85%

Change in dielectric relaxation with the presence of water in highly filled composites

Tuncer

2017

J. Adv. Dielect.

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It is important to determine the dielectric characteristics of semiconductor encapsulation materials based on epoxy resins. We employed the dielectric spectroscopy technique to investigate the dielectric relaxation in the presence of water and how it changes the relaxation. It was observed that the dielectric relaxation of the material was significantly influenced by absorbed water, the local segmental motion (also known as Johari-Goldstein ( ) relaxation) was influenced most by the presence of the water, it was modified by the wet sample compared to dry one, and required high activation energy. The relaxation related to the glass transition was contributed by the cooperative motion (the -relaxation) of the epoxy resin system. The -relaxation was shifted to a low temperature in the wet sample compared to dry one. The relaxation was modeled with a clear Vogel-Fulcher-Tammann-Hesse (VFTH) behavior; the Vogel temperature of the wet sample was 8 K lower than the dry sample. The presence of water acts as a plasticizer for the molecular relaxation, and speed-up the cooperative process. The measured data were also used to estimate the electrical properties of the resin system by employing an effective-medium model together with a porous media continuum model by taking into account the physical properties of the system. It is already known that the influence of water in semiconductor packaging is important in sensitive applications. The presented measurements and the analysis method would be appreciated within the semiconductor packaging community to improve material selection and performance evaluation efforts.

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Section: Dielectric Relaxation Mapmentioning

confidence: 85%

Change in dielectric relaxation with the presence of water in highly filled composites

Tuncer

2017

J. Adv. Dielect.

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“…The Raman spectroscopy results combined with chemometric analyses reveal that lactose-hydrolyzed dairy products do not crystallize when subjected to conditions favorable for glass transition. (Roos & Karel, 1991;Zhu et al, 2011); inulin Tg 120°C, ΔCp 0,65 J·kg -1 ·°C -1 (Zimeri and Kokini, 2002). …”

Section: Discussionmentioning

confidence: 99%

Technological aspects of lactose-hydrolyzed milk powder

Torres

Stephani

Tavares

et al. 2017

Food Research International

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Few reports describe the effect of lactose hydrolysis on the properties of milk powder during production and storage. Hence, the aim of this study was to evaluate the effects of five different levels of enzymatic lactose hydrolysis during the production and storage of milk powder. As the lactose hydrolysis rate increased, adhesion to the drying chamber also increased, due to higher levels of particle agglomeration. Additionally, more brown powder was obtained when the lactose hydrolysis rate was increased, which in turn negatively affected rehydration ability. Using Raman spectroscopy, crystallization of the lactose residues in various samples was assessed over 6 weeks of accelerated aging at a room temperature environment with 75.5 % of air moisture.Products with 25% or greater lactose hydrolysis showed no signs of crystallization, in contrast to the non-hydrolyzed sample.

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“…Recently, the stability of inulin during the storage has been evaluated and related to the concepts of a w and Tg, where a w is expressed as the amount of water adsorbed per 100 g of dried sample. In other works, inulin was analyzed as a model system: Blecker et al (2003) discussed about the structure, stability, and texture of inulin as a fiber, highlighting the importance of this ingredient in the dietary fiber, fat substitute, and in other applications in the food industry; Kawai et al (2011) investigated the effect of water content, molecular weight, and crystallinity on the Tg; Zimeri and Kokini (2002) determined the Tg for inulin and inulin-water mixtures at different water contents, finding that Tg increases at low water contents, when inulin is semicrystalline and at high molecular weights; Ronkart et al, (2006Ronkart et al, ( , 2009) studied the Tg for inulin with different polymerization degrees, finding that Tg increases with the degree of polymerization. Saavedra et al (2014) found that, up to a water content of 10 % and water activity of 0.6, the structure of inulin remains stable and without agglomeration; however, at levels higher than 15 % and 0.8, agglomerations were observed.…”

Section: Phase Stabilitymentioning

confidence: 99%