Effect of Water Activity and Temperature in Color and Chlorophylls Changes in Yerba Mate Leaves

Figures & data

Figure 1 Experimental and theoretical values for chlorophylls a and b at 60°C and different water activities.

Figure 2 Experimental and theoretical values for chlorophylls a and b at aw₂ (0.652-0.690) and different temperatures.

Table 1 Constants of the first order kinetic “k” (Eq. 1) and correlation coefficient for chlorophyll a in hours⁻¹.

Water activity	k-values (h^−1) (correlation coefficient)
	50°C	60°C	70°C	80°C
aw1 (0.789-0.812)	0.0620(0.980)	0.1474 (0.996)	0.2143 (0.998)	0.5433 (0.993)
aw2 (0.652-0.690)	0.0249 (0.995)	0.0578 (0.997)	0.1405 (0.998)	0.4584 (0.993)
aw3 (0.497-0.514)	0.0094 (0.993)	0.0371 (0.988)	0.1332 (0.995)	0.2255 (0.995)
aw4 (0.260-0.305)	0.0053 (0.994)	0.0158 (0.994)	0.0664 (0.996)	0.1028 (0.995)
aw5 (0.105-0.111)	0.0046 (0.992)	0.0138 (0.998)	0.0611 (0.990)	0.0655 (0.993)

Table 2 Constants of the first order kinetic “k” (Eq. 1) and correlation coefficient for chlorophyll b in hours⁻¹.

Water activity	k-values (h^−1) (correlation coefficient)
	50°C	60°C	70°C	80°C
aw1 (0.789-0.812)	0.0265 (0.997)	0.0794 (0.998)	0.1125 (0.996)	0.2968 (0.994)
aw2 (0.652-0.690)	0.0088 (0.994)	0.0239 (0.997)	0.0610 (0.995)	0.2258 (0.980)
aw3 (0.497-0.514)	0.0043 (0.997)	0.0140 (0.986)	0.0596 (0.993)	0.0999 (0.990)
aw4 (0.260-0.305)	0.0043 (0.993)	0.0107 (0.995)	0.0334 (0.997)	0.0579 (0.997)
aw5 (0.105-0.111)	0.0042 0.994)	0.0111 (0.998)	0.0380 (0.998)	0.0497 (0.997)

Table 3 Constant values of Eq. (3) (a, b, c, d) for chlorophylls a and b and color and mean percentage error (MPE).

	a	b	c	d	MPE
Chlorophyll a	32.32	−6.98	−12369.6	−0.273	7.90
Chlorophyll b	26.73	2.98	−10572.5	0.022	7.42
Parameter color a*	19.79	2.07	−8568.1	−0.057	6.09

Figure 3 Experimental and predicted values of rate constant with Eq. (3) for Chlorophyll a.

Figure 4 Experimental and predicted values of rate constant with Eq. (3) for Chlorophyll b.

Figure 5 “a*/a₀*” values at aw₂ (0.652-0.690) at different temperatures.

Figure 6 Experimental and predicted values of rate constant with Eq. (3) for color parameter. “a*”

Table 4 Constants of the first order kinetic “k” (Eq. 4) and correlation coefficient for color parameter “a*” in hours⁻¹.

“a”	k-values (h^−1) (correlation coefficients)
	50°C	60°C	70°C	80°C
aw1 (0.789-0.812)	0.01722 (0.989)	0.0361 (0.990)	0.0533 0.988)	0.0747 (0.985)
aw2 (0.652-0.690)	0.0070 (0.994)	0.0159 (0.991)	0.0278 (0.994)	0.0894 (0.948)
aw3 (0.497-0.514)	0.0029 (0.994)	0.0107 (0.986)	0.0184 (0.991)	0.0517 (0.992)
aw4 (0.260-0.305)	0.0022 (0.990)	0.0044 (0.991)	0.0080 (0.995)	0.0015 (0.993)
aw5 (0.105-0.111)	0.0009 (0.988)	0.0029 (0.995)	0.0086 (0.990)	0.0061 (0.995)