Physical State Study of (Sugar Mixture)-Polymer Model Systems

Figures & data

Table 1 Anhydrous glass transition temperature (T_g) as well as glass transition temperature (T_g´), and onset of ice melting temperature (T_m´) of maximally freeze-concentrated solutions of lactose/sucrose and lactose/sucrose protein and lactose/sucrose cornstarch mixtures (C_g´) for various sugar/proteins and polysaccharide mixtures. A 15 min annealing time was used for all solutions

Material	Annealingtemperature (°C)	Tg (°C)(Onset)	Tg´ (°C)(Onset)	Tm´ (°C)(Onset)	k^†	Cg´*(%)
Lactose/sucrose (1:1)	−34	80^a	−43^a	−33^a	5.4	82
Lactose/sucrose/albumin (1:1:1)	−32	98^b	−51^b	−31^b	6.8	80
Lactose/sucrose/ gelatine (1:1:1)	−29	101^c	−51^b	−28^c	5.8	77
Lactose/sucrose/ cornstarch (1:1:1)	−35	103^d	−48^c	−25^d	6.4	80
Lactose/sucrose/ gelatine/ cornstarch (1:1:1:1)	−25	111^e	−46^d	−26^d	6.4	80
Mean values ± standard deviation followed by different letters (a, b, c, d) within the same column are differ significantly (P ≤ 0.05). ^†Constant k for Gordon and Taylor eq.[18]; *Calculated using Gordon and Taylor eq.[18]

Figure 1 Thermograms of 20%, lactose/ sucrose, lactose/ sucrose/ albumin (1:1), lactose/ sucrose/ gelatin (1:1:1), lactose/ sucrose/ cornstarch (1:1:1), and lactose/ sucrose/ gelatin/c ornstarch (1:1:1:1) solutions isothermally annealed at (T_m´−1)°C for 15 minutes before determination of the transitions during rewarming from –100 to 20°C at 5°C min⁻¹.

Figure 2 DSC thermograms (Second scan) of freeze-dried anhydrous, lactose/ sucrose (1:1), lactose/ sucrose/ albumin (1:1:1), lactose/ sucrose/ gelatin (1:1:1), lactose/ ucrose/ cornstarch (1:1:1), and lactose/ sucrose/ gelatin/ cornstarch (1:1:1:1). The arrow indicates the onset of T_g.

Figure 3 State diagrams for lactose/sucrose, lactose/sucrose/albumin (1:1:1), lactose/ sucrose/ gelatin (1:1:1), lactose/ sucrose/ cornstarch (1:1:1), and lactose/ sucrose/ cornstarch/ gelatin (1:1:1:1). T_g curve was predicted by the Gordon and Taylor equation (Gordon and Taylor, 1952).[37] Below T_g all solutions were in the glassy state. Maximally freeze concentrated solutions showed constant T_g´ (onset of glass transition temperature) and T_m´ (onset of ice melting temperature) values. All solution showed maximum concentration of solute in the unfrozen phase at C_g´.

Table 2 The glass transition temperature (T_g´), and onset of ice melting temperature (T_m´) of maximally freeze-concentrated solutions of sugar mixtures/proteins/cornstarch mixtures. A 15 min annealing time was used for all solutions

Sugar mixtures(1:1)	Transition temperatures for sugar mixture solutions (1:1)		Transition temperatures for mixed sugars-albumen (1:1:1)		Transition temperatures for mixed sugars-gelatin (1:1:1)		Transition temperatures for mixed sugars-cornstarch (1:1:1)
	Tg´ (°C)(Onset)	Tm´ (°C)(Onset)	Tg´ (°C)(Onset)	Tm´ (°C)(Onset)	Tg´ (°C)(Onset)	Tm´ (°C)(Onset)	Tg´ (°C)(Onset)	Tm´ (°C)(Onset)
Lactose/sucrose (1:1)	−43^a	−33^a	−51^a	−31^a	−51^a	−28^a	−48^a	−25^a
Lactose/trehalose (1:1)	−40^b	−31^b	−48^b	−30^a	−50^a	−28^a	−47^a	−30^b
Sucrose/trehalose (1:1)	−44^c	−33^b	−51^a	−31^a	−49^b	−30^b	−48^a	−28^c
Mean values ± standard deviation followed by different letters (a, b, c) within the same column are differ significantly (P ≤ 0.05).

Figure 4 a) Thermograms of 20% solutions, lactose/sucrose (1:1), lactose/ trehalose (1:1), and sucrose/ trehalose isothermally annealed at (T_m´−1) °C for 15 minutes before determination of the transitions during rewarming from –100 to 20°C at 5°C min⁻¹. b) Thermograms of 20% solutions, lactose/ sucrose/ albumin (1:1:1), lactose/ trehalose/ albumin (1:1:1), and sucrose/ trehalose/ albumin (1:1:1) isothermally annealed at (T_m´−1) °C for 15 minutes before determination of the transitions during rewarming from –100 to 20°C at 5°C min⁻¹. c) Thermograms of 20% solutions, lactose/ sucrose/ gelatin (1:1:1), lactose/ trehalose/ gelatin (1:1:1), and sucrose/trehalose/gelatin (1:1:1) isothermally annealed at (T_m´−1) °C for 15 minutes before determination of the transitions during rewarming from –100 to 20°C at 5°C min⁻¹. d) Thermograms of 20%, lactose/sucrose/cornstarch (1:1:1), lactose/ trehalose /cornstarch (1:1:1), and sucrose/ trehalose/ cornstarch (1:1:1) isothermally annealed at T_m´−1 for 15 minutes before determination of the transitions during rewarming from –100 to 20°C at 5°C min⁻¹.

Singh , K.J. and Roos , Y.H. 2006 . State transitions and freeze concentration in trehalose–protein–cornstarch mixtures . Lebensm.-Wiss.u.-Technol. , 39 ( 8 ) : 930 – 938 .

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Gordon , M. and Taylor , J.S. 1952 . Ideal copolymers and the second-order transitions of synthetic rubbers. I. Non-crystalline copolymers . J. Appl. Chem. , 2 : 493 – 500 .

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