Water and Solids Mobility in Foods

Schmidt, Shelly J.

doi:10.1016/s1043-4526(04)48001-2

Cited by 82 publications

(77 citation statements)

References 135 publications

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“…1 H NMR spin-lattice relaxation time (T1) has also been related to molecular mobility, but spin-spin relaxation time (T2) measurements are primarily used to study matrix mobility in food. 6,7 Spin-spin relaxation time is affected by changes in the internal environment arising from chemical exchanges such as those involved in molecular mobility. 8 Single-pulse 1 H NMR experiments are used to study low-mobility proton pools with T2 of 10-1000 µs.…”

Section: Objectivementioning

confidence: 99%

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Determination of the Gelation Mechanism of Freeze–Thawed Hen Egg Yolk

Acevedo

Horner

et al. 2015

J. Agric. Food Chem.

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A study of yolks stored up to 168 d at −20 °C was conducted to determine the gelation behavior and mechanism of freeze–thawed yolk. Methods used were rheology, native and sodium dodecyl sulfate polyacrylamide gel electrophoresis (native- and SDS-PAGE), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), particle size analysis, and proton nuclear magnetic resonance (1H NMR) spectroscopy for matrix mobility. Results indicate that both constituents of plasma and granules contributed to gelation of yolk under freezing. PAGE analyses suggest that granular proteins participated in aggregation during freeze–thaw. Increasing gel strength and particle size and decreasing water and lipid–water mobility indicate that lipoproteins or apolipoproteins aggregated. At storage times ≥84 d, increased protein and lipid mobility, the detection of smaller particles, and secondarily increased gel strength suggest the liberation of protein or lipoprotein components from previously formed aggregates and further aggregation of these constituents. Disruption of the gelled yolk matrix observed with TEM supported that ice crystal formation was required for gelation to occur. A two-stage dynamic gelation model is thus proposed.

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Section: Objectivementioning

confidence: 99%

“…In this study, fresh and gelled yolk (stored at -20°C for 0, 1,3,7,14,28,84, and 168 d and thawed) were examined to determine the effect of varying frozen storage times on yolk gelation. Our preliminary results indicated that frozen storage time had an effect on gelation.…”

Section: Introductionmentioning

confidence: 99%

Determination of the Gelation Mechanism of Freeze–Thawed Hen Egg Yolk

Acevedo

Horner

et al. 2015

J. Agric. Food Chem.

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“…A sudden decrease in T 1 to certain temperature (T RLL ) and a sudden increase is observed. The change in T 2 is small at low temperatures, while a sudden increase in T 2 is observed after a certain temperature (T RLL ) (Adapted from [122]) observation of T g is often dependent on the application, the information required and the material of interest [187,188].…”

Section: Nuclear Magnetic Resonancementioning

confidence: 99%

A Review of Methods, Data and Applications of State Diagrams of Food Systems

2010

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Understanding of the amorphous glassy state of food systems is often crucial in determining physicochemical characteristics and predicting stability of dehydrated and frozen foods. At the glass transition temperature (T g ) of food components, transformation from the amorphous glassy state to the liquid-like rubbery state occurs. T g and ice-melting temperatures (T m ) of food systems are used to construct their state diagrams, in which the different physical states/phases and state/phase transitions of food components are presented in relation to temperature and concentration. A state diagram may be used to identify the appropriate processing and storage conditions of food systems. An overview of determination methods is carried out for glass transition temperature, ice-melting temperature and conditions of maximum-freeze-concentration (glass transition temperature of maximum-freeze-concentrated solution, T g 0 and onset of ice-melting temperature, T m 0 ) for food systems. The data as T g , T m , T g 0 and T m 0 are necessary for construction of state diagrams of foods. The advantages and limitations of the determination methods are discussed. Combined data for glass transition temperature, ice-melting temperature and conditions of maximum-freeze concentration for selected food systems are presented in this study. The effect of food composition on glass line, freezing/melting curve and maximum-freezeconcentration conditions is evaluated. The significance of the state diagrams in predicting the physical, chemical and microbial stability in foods is briefly examined. Glass transition concept and state diagrams are useful for describing the physical and structural stability of food systems at specific conditions, yet they are not considered as the only determining factors of chemical, biochemical and microbial stability of food systems.

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“…The three-dimensional space formed after the removal of the water species creates micropores accompanying the production of various structures with various degrees of porosity and kinds of labyrinths (see Figure 14). Considering the water activity map presented by many researchers (Labuza et al, 1970;Van den Berg and Bruin, 1981;Rockland and Stewart, Eds., 1981;Schmidt, 2004), the three regions are evident in the water activity space.…”

Section: Featuresmentioning

confidence: 95%

Advantage of the Hybrid Method of Chemical Engineering - Proton NMR Technique for Food Engineering

Konishi

Kobayashi²

2013

FSTR

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As a new scientific method to overcome the difficulties in designing requested food products in the food engineering field, a hybrid method combining the chemical engineering-proton NMR technique was examined by using 18 different kinds of foods. The hybrid method proposed clearly distinguished water species-A 1 and -A 2 , which were divided at the correlation time of τ C = 1 × 10 −8 s evaluated by the proton NMR technique. Water species-A 1 was recognized as a weakly restricted water species, such as free water, whereas water species-A 2 was recognized as a strongly restricted water species, such as bound water formed by strong adsorption. It was clearly demonstrated that the two water species were reproduced during repeated cycles of dehydration and re-hydration. All the parameters, such as effective diffusivity of water (De), activation energy of De (E D ), pre-exponential factor of De (δD 0 ) and hardness (N P ) of food, were evaluated individually for the two water species.

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Water and Solids Mobility in Foods

Cited by 82 publications

References 135 publications

Determination of the Gelation Mechanism of Freeze–Thawed Hen Egg Yolk

Determination of the Gelation Mechanism of Freeze–Thawed Hen Egg Yolk

A Review of Methods, Data and Applications of State Diagrams of Food Systems

Advantage of the Hybrid Method of Chemical Engineering - Proton NMR Technique for Food Engineering

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