Copigmentation effects and thermal degradation kinetics of purple sweet potato anthocyanins with metal ions and sugars

Applied Biological Chemistry

Table 2 The spectroscopic parameters of hyperchromic effect (expressed as (A − A ₀)/A ₀) of PSPAs (0.1 g L⁻¹) on complex formation with sugars in pH 4 buffer

Glucose		Sucrose		Fructose
Concentration (g L⁻¹)	Hyperchromic effect (%)	Concentration (g L⁻¹)	Hyperchromic effect (%)	Concentration (g L⁻¹)	Hyperchromic effect (%)
10	−0.27 ± 0.47^a	10	−0.67 ± 0.28	10	−0.37 ± 0.27
50	1.40 ± 0.42	50	−0.07 ± 0.19	50	2.53 ± 0.40
100	3.44 ± 0.14*	100	2.40 ± 0.81*	100	5.40 ± 1.03**
150	5.61 ± 0.90***	150	2.84 ± 0.42*	150	5.40 ± 1.18**
200	9.21 ± 1.06***	200	3.64 ± 0.99*	200	5.03 ± 0.42**
250	10.68 ± 0.99***	250	6.84 ± 0.71***	250	8.33 ± 1.26***
300	11.25 ± 1.24***	300	8.54 ± 0.57***	300	8.93 ± 1.35***

Maltodextrin		Konjac glucomannan		Sodium carboxymethyl cellulose
Concentration (g L⁻¹)	Hyperchromic effect (%)	Concentration (g L⁻¹)	Hyperchromic effect (%)	Concentration (g L⁻¹)	Hyperchromic effect (%)
0.1	−0.27 ± 0.64	0.1	1.24 ± 0.54	0.1	−0.51 ± 0.79
0.5	−0.12 ± 0.45	0.2	1.44 ± 0.12	0.5	−0.59 ± 0.60
1	0.48 ± 0.55	0.4	5.66 ± 0.83**	1	−1.46 ± 0.35
2	−0.27 ± 0.64	0.8	6.76 ± 0.24**	2	−0.84 ± 0.09
4	1.99 ± 0.25	1.2	10.56 ± 1.27***	3	−0.68 ± 0.45
8	2.44 ± 0.38*	1.6	16.64 ± 1.12***	4	0.08 ± 0.37

^aNegative values mean hypochromic effect
*, **, *** Significance levels of p < 0.05, 0.01, 0.001, respectively, by comparing the absorbance (A) of copigmented PSPAs solution with the value (A ₀) of corresponding solution without adding sugars by multiple comparison analysis