Towards an improved understanding of glass transition and relaxations in foods: molecular mobility in the glass transition range

Champion, Dominique; Meste, M. Le; Simatos, D.

doi:10.1016/s0924-2244(00)00047-9

Cited by 252 publications

(172 citation statements)

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“…These physical changes were successfully explained and predicted by the glass transition concept on the basis of glass transition temperature (T g ) as a reference temperature (Chuy and Labuza 1994). Such physical transformations have been observed to occur above T g ( Aguilera et al 1995;Champion et al 2000). Table 8 show's the thermal behaviour of SFJP.…”

Section: Nutritional Properties Of Sfjpmentioning

confidence: 83%

Optimization of spray drying process for developing seabuckthorn fruit juice powder using response surface methodology

Selvamuthukumaran

Khanum

2012

J Food Sci Technol

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The response surface methodology was used to optimize the spray drying process for development of seabuckthorn fruit juice powder. The independent variables were different levels of inlet air temperature and maltodextrin concentration. The responses were moisture, solubility, dispersibility, vitamin C and overall color difference value. Statistical analysis revealed that independent variables significantly affected all the responses. The Inlet air temperature showed maximum influence on moisture and vitamin C content, while the maltodextrin concentration showed similar influence on solubility, dispersibility and overall color difference value. Contour plots for each response were used to generate an optimum area by superimposition. The seabuckthorn fruit juice powder was developed using the derived optimum processing conditions to check the validity of the second order polynomial model. The experimental values were found to be in close agreement to the predicted values and were within the acceptable limits indicating the suitability of the model in predicting quality attributes of seabuckthorn fruit juice powder. The recommended optimum spray drying conditions for drying 100 g fruit juice slurry were inlet air temperature and maltodextrin concentration of 162.5°C and 25 g, respectively. The spray dried juice powder contains higher amounts of antioxidants viz., vitamin C, vitamin E, total carotenoids, total anthocyanins and total phenols when compared to commercial fruit juice powders and they are also found to be free flowing without any physical alterations such as caking, stickiness, collapse and crystallization by exhibiting greater glass transition temperature.

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Section: Nutritional Properties Of Sfjpmentioning

confidence: 83%

Optimization of spray drying process for developing seabuckthorn fruit juice powder using response surface methodology

Selvamuthukumaran

Khanum

2012

J Food Sci Technol

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“…The Stokes-Einstein relation is not expected to predict with high accuracy the diffusion rates of small gas molecules such as OH, O 3 , NO x , NH 3 , and H 2 O and may be inaccurate near the glass transition RH Shiraiwa et al, 2011). However, the Stokes-Einstein relationship should give reasonable estimations of diffusion rates for large organic molecules for conditions not close to the glass transition temperature of the matrix (Champion et al, 2000;Koop et al, 2011;Shiraiwa et al, 2011;Power et al, 2013;Marshall et al, 2016).…”

Section: Discussionmentioning

confidence: 99%

“…In the figure, the boxes represent the median, 25th, and 75th percentiles and the whiskers show the 10th and 90th percentiles. In addition to RH, viscosity can depend strongly on temperature (Champion et al, 1997;Koop et al, 2011). For example, the viscosity of solutions of sucrose and water may increase by 2-3 orders of magnitude for a 10 K decrease in temperature close to the glass transition temperature (Champion et al, 1997).…”

Section: Atmospheric Implicationsmentioning

confidence: 99%

“…In addition to RH, viscosity can depend strongly on temperature (Champion et al, 1997;Koop et al, 2011). For example, the viscosity of solutions of sucrose and water may increase by 2-3 orders of magnitude for a 10 K decrease in temperature close to the glass transition temperature (Champion et al, 1997). However, the effect of temperature on the viscosity of toluene-derived SOM has not been quantified.…”

Section: Atmospheric Implicationsmentioning

confidence: 99%

“…After determining viscosities as a function of RH, the Stokes-Einstein equation is used to convert the viscosities into equivalent diffusion rates of large organic molecules within toluene-derived SOM. The Stokes-Einstein equation should give reasonable values of diffusion rates when the viscosity is not near the viscosity of a glass (∼ 10 12 Pa s) and when the molecules are roughly the same size or larger than the molecules in the SOM matrix (Champion et al, 2000;Koop et al, 2011;Shiraiwa et al, 2011;Power et al, 2013). Finally, the results are used to estimate the viscosities and diffusion rates in organic particulate matter over megacities.…”

Section: Introductionmentioning

confidence: 99%

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Relative humidity-dependent viscosity of secondary organic material from toluene photo-oxidation and possible implications for organic particulate matter over megacities

et al. 2016

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Abstract. To improve predictions of air quality, visibility, and climate change, knowledge of the viscosities and diffusion rates within organic particulate matter consisting of secondary organic material (SOM) is required. Most qualitative and quantitative measurements of viscosity and diffusion rates within organic particulate matter have focused on SOM particles generated from biogenic volatile organic compounds (VOCs) such as α-pinene and isoprene. In this study, we quantify the relative humidity (RH)-dependent viscosities at 295 ± 1 K of SOM produced by photo-oxidation of toluene, an anthropogenic VOC. The viscosities of toluene-derived SOM were 2 × 10 −1 to ∼ 6 × 10 6 Pa s from 30 to 90 % RH, and greater than ∼ 2 × 10 8 Pa s (similar to or greater than the viscosity of tar pitch) for RH ≤ 17 %. These viscosities correspond to Stokes-Einstein-equivalent diffusion coefficients for large organic molecules of ∼ 2 × 10 −15 cm 2 s −1 for 30 % RH, and lower than ∼ 3 × 10 −17 cm 2 s −1 for RH ≤ 17 %. Based on these estimated diffusion coefficients, the mixing time of large organic molecules within 200 nm toluene-derived SOM particles is 0.1-5 h for 30 % RH, and higher than ∼ 100 h for RH ≤ 17 %. As a starting point for understanding the mixing times of large organic molecules in organic particulate matter over cities, we applied the mixing times determined for toluene-derived SOM particles to the world's top 15 most populous megacities. If the organic particulate matter in these megacities is similar to the toluene-derived SOM in this study, in Istanbul, Tokyo, Shanghai, and São Paulo, mixing times in organic particulate matter during certain periods of the year may be very short, and the particles may be wellmixed. On the other hand, the mixing times of large organic molecules in organic particulate matter in Beijing, Mexico City, Cairo, and Karachi may be long and the particles may not be well-mixed in the afternoon (15:00-17:00 LT) during certain times of the year.

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Flavor Delivery Systems

Ubbink

Schoonman

2003

Kirk-Othmer Encyclopedia of Chemical Technology

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An overview is given of flavor delivery systems and technologies for flavor encapsulation. A central conceptual distinction made is between systems aimed at protecting the encapsulated flavor against evaporation and the adverse effects of environmental oxygen in low‐moisture states, and those whose principal aim is to modify the release of the encapsulated flavor during food processing, storage, or consumption. The former class of systems, which are designated as glass‐encapsulation systems since they are invariably based on amorphous carbohydrates in the glassy state, are generally prepared by well‐established technologies like spray drying and melt extrusion. These systems have found widespread commercial application. Accounts are given of the most‐used technologies and of the underlying material science. The latter class of systems, principally aimed at controlling the release rate of the encapsulated flavor, is far more diverse in composition, working principle, and manufacturing technology. Their common feature is that, in the food matrix, they retain a core structure whose role is to control both the rate and the extent of release of the encapsulated flavor. It is argued that application of such systems necessitates a careful tuning of the delivery system to both the specific composition of the flavor, the composition and structure of the food matrix and the conditions during food processing, storage and consumption, because of the comparatively well‐defined release aimed for. Several of the principal technologies are highlighted. Examples are given of successful applications in food matrices. It is conjectured that limitations currently experienced in the application of controlled release systems for flavors and that impede a truly widespread adoption in the food industry can only be eliminated by a concerted approach including encapsulation technology, flavor physico‐chemistry and chemistry, food materials science, and focused product development efforts.

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Towards an improved understanding of glass transition and relaxations in foods: molecular mobility in the glass transition range

Cited by 252 publications

References 69 publications

Optimization of spray drying process for developing seabuckthorn fruit juice powder using response surface methodology

Optimization of spray drying process for developing seabuckthorn fruit juice powder using response surface methodology

Relative humidity-dependent viscosity of secondary organic material from toluene photo-oxidation and possible implications for organic particulate matter over megacities

Flavor Delivery Systems

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