THERMAL AND DYNAMIC-MECHANICAL PROPERTIES OF FROZEN WHEAT DOUGHS WITH ADDED SUCROSE, NaCl, ASCORBIC ACID, AND THEIR MIXTURES

Figures & data

Figure 1. DSC thermograms for frozen wheat dough+sucrose, dough+NaCl, and dough+sucrose+NaCl and also their onset of ice melting temperatures, T′_m, and relative unfrozen water contents, W′_g (g H₂O/g solute).

Table 1. The Onset Temperatures of Ice Melting (T′_m), Relative Amounts of the Unfrozen Water Content, W′_g (g H₂O/g solute), and Relative Solid Concentrations in Unfrozen Water, C′_g (Weight % Solute) for Different Doughs Measured by DSC

Sample	T′m (°C)	W′g (g H2O/g solute)	C′g (weight % solute)
Dough (flour+water) ^(a)	−18 ± 0.5	0.35 ± 0.00	74.3 ± 0.2
Dough+sucrose	−26 ± 0.5	0.38 ± 0.00	72.7 ± 0.2
Dough+NaCl	−26 ± 1.0	0.37 ± 0.00	72.9 ± 0.0
Dough+AA ^(b)	−18 ± 0.5	0.35 ± 0.00	74.3 ± 0.1
Dough+sucrose+NaCl	−26 ± 1.0	0.38 ± 0.00	72.5 ± 0.0
Dough+sucrose+NaCl+AA ^(b)	−26 ± 0.5	0.38 ± 0.00	72.5 ± 0.0

^(a)Data from Laaksonen and Roos¹⁰.

^(b)Ascorbic acid.

Figure 2. The loss modulus (G′′) of frozen wheat dough with added sucrose, as a function of temperature, as measured by DMA at 2.5, 5 and 10 Hz.

Figure 3. The loss modulus (G″) of frozen wheat dough with added sucrose, as a function of whole temperature range, as measured by DMA at 2.5, 5 and 10 Hz.

Table 2. The Onset and Endset Temperatures of β- and γ-relaxation, the Glass Transition Temperatures (T′_g), and Onset of Ice Melting Temperatures (T′_m) of Different Wheat Doughs, as Measured by DMA and T′_m of Different Wheat Doughs Measured by DSC

	Relaxation (°C)
	γ		β
Sample	Onset	Endset	Onset	Endset	T′g (°C)	T′m (°C)	T′ ^(c) m(°C)
Dough (flour+water) ^(a)	−136 ± 1.0	−106 ± 0.5	−65 ± 1.5	−50 ± 1.0	−34 ± 0.5	−20 ± 0.5	−18 ± 0.5
Dough+sucrose	−136 ± 1.0	−100 ± 1.5	−91 ± 1.5	−70 ± 1.0	−31 ± 1.0	−25 ± 0.0	−26 ± 0.5
Dough+NaCl	−141 ± 1.0	−108 ± 0.5	−102 ± 1.5	−40 ± 1.0	−31 ± 0.5	−26 ± 0.5	−26 ± 0.5
Dough+AA ^(b)	−136 ± 1.0	−106 ± 1.0	−65 ± 1.0	−50 ± 1.5	−34 ± 0.5	−20 ± 0.5	−18 ± 0.5
Dough+suc+NaCl	−146 ± 0.5	−124 ± 1.0	−118 ± 1.5	−64 ± 0.5	−31 ± 0.5	−26 ± 0.5	−26 ± 1.0
Dough+suc+NaCl+AA ^(b)	−146 ± 1.0	−124 ± 1.0	−118 ± 0.5	−64 ± 1.0	−31 ± 0.5	−26 ± 0.5	−26 ± 0.5

^(a)Data from Laaksonen and Roos [10].

^(b)Ascorbic acid.

^(c)Measured by DSC.

Figure 4. The loss modulus (G″) of frozen wheat dough with added NaCl, as a function of temperature, as measured by DMA at 2.5, 5 and 10 Hz.

Figure 5. The loss modulus (G″) of frozen wheat dough with added sucrose and NaCl, as a function of temperature, as measured by DMA at 2.5, 5 and 10 Hz.

Laaksonen , T. J. and Roos , Y. H. 2000 . Thermal, Dynamic-Mechanical, and Dielectric Analysis of Phase and State Transitions of Frozen Wheat Doughs . J. Cereal Sci. , 32 : 281 – 292 .

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