scholarly journals Estimation of the apparent glass transition temperature of spray-dried emulsified powders and yeast powders by their flavor release behavior under temperature ramping conditions

2018 ◽  
Author(s):  
A. Sultana ◽  
J. L. Zhu ◽  
H. Yoshii
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Spray Drying ◽  
Yeast Cells ◽  
Release Behavior ◽  
Simple Method ◽  
Flavor Release ◽  
Yeast Powder ◽  
Spray Dried

Flavor release from powders depends on the glass transition temperature (Tg) and water absorption. This study reports a simple method to estimate the apparent Tg by aroma sensing upon flavor release from spray-dried powders. Four different wall materials (maltodextrin (MD), MD blends with fructose at 20 and 40wt%, and yeast cells) were used to encapsulate flavors by spray-drying. The apparent Tg values of MD and MD with 20 and 40wt% fructose were determined as 130, 110, and 75 °C, respectively, similar to those calculated by the Gordon–Taylor equation. The slow flavor release from dried-yeast powder afforded the highest Tg. Keywords: yeast; flavor; encapsulation; spray drying; aroma sensor.

scholarly journals Long-Term Physical (In)Stability of Spray-Dried Amorphous Drugs: Relationship with Glass-Forming Ability and Physicochemical Properties

Pharmaceutics ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 425 ◽  
Author(s):  
Edueng ◽  
Bergström ◽  
Gråsjö ◽  
Mahlin
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Physicochemical Properties ◽  
Physical Stability ◽  
Glass Forming Ability ◽  
Melt Quenching ◽  
Glass Forming ◽  
Spray Dried

This study shows the importance of the chosen method for assessing the glass-forming ability (GFA) and glass stability (GS) of a drug compound. Traditionally, GFA and GS are established using in situ melt-quenching in a differential scanning calorimeter. In this study, we included 26 structurally diverse glass-forming drugs (i) to compare the GFA class when the model drugs were produced by spray-drying with that when melt-quenching was used, (ii) to investigate the long-term physical stability of the resulting amorphous solids, and (iii) to investigate the relationship between physicochemical properties and the GFA of spray-dried solids and their long-term physical stability. The spray-dried solids were exposed to dry (<5% RH) and humid (75% RH) conditions for six months at 25 °C. The crystallization of the spray-dried solids under these conditions was monitored using a combination of solid-state characterization techniques including differential scanning calorimetry, Raman spectroscopy, and powder X-ray diffraction. The GFA/GS class assignment for 85% of the model compounds was method-dependent, with significant differences between spray-drying and melt-quenching methods. The long-term physical stability under dry condition of the compounds was predictable from GFA/GS classification and glass transition and crystallization temperatures. However, the stability upon storage at 75% RH could not be predicted from the same data. There was no strong correlation between the physicochemical properties explored and the GFA class or long-term physical stability. However, there was a slight tendency for compounds with a relatively larger molecular weight, higher glass transition temperature, higher crystallization temperature, higher melting point and higher reduced glass transition temperature to have better GFA and better physical stability. In contrast, a high heat of fusion and entropy of fusion seemed to have a negative impact on the GFA and physical stability of our dataset.

Water sorption isotherms and glass transition temperature of spray dried tomato pulp

2008 ◽  
Vol 85 (1) ◽  
pp. 73-83 ◽  
Author(s):  
Athanasia M. Goula ◽  
Thodoris D. Karapantsios ◽  
Dimitris S. Achilias ◽  
Konstantinos G. Adamopoulos
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Water Sorption ◽  
Sorption Isotherms ◽  
Tomato Pulp ◽  
Spray Dried ◽  
Water Sorption Isotherms

scholarly journals Thermal and thermodynamic characterization of a dye powder from liquid turmeric extracts by spray drying

2016 ◽  
Vol 69 (1) ◽  
pp. 7845-7854 ◽  
Author(s):  
Aura Yazmin Coronel Delgado ◽  
Héctor José Ciro Velásquez ◽  
Diego Alonso Restrepo Molina
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Glass Transition ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Mass Loss ◽  
Spray Drying ◽  
Transient Flow ◽  
Sorption Isotherms

This study aimed to evaluate the thermodynamic properties of sorption isotherms and glass transition temperature (Tg) and the thermal properties of a dye powder obtained from turmeric extracts using spray drying. The sorption isotherms were evaluated at 15, 25 and 35 °C using the dynamic gravimetric method, wherein the isotherm data of the experiment were fit to GAB and BET models. Likewise, the Tg was measured using differential scanning calorimetry (DSC). Thermogravimetric analysis (TGA) was used to determine the mass loss, and the thermal properties (heat capacity, diffusivity and thermal conductivity) were determined using transient flow method. The results demonstrated that the GAB model best fit the adsorption data. The DSC analysis presented a glass transition temperature of 65.35 °C and a loss of volatiles at 178.07 °C. The TGA analysis indicated a considerable mass loss starting at 193 °C, resulting in degradation of the product. The thermal properties demonstrated a heat capacity of 2.45 J/g °C, a thermal conductivity of 0.164 ± 0.001 W/mK and a thermal diffusivity of 8.7x10-8 ± 0.000 m2/s.

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