Anthocyanin Extract from Blackberry Used as an Indicator of Hydrogen Potential

Figures & data

Table 1. Factorial design 2⁴ to the extraction of anthocyanin from Castilla and Wild blackberry.

Run	X1 Variety of blackberry	X2 Type of Raw material	X3 Microwave pretreatment	X4 Extraction method	Y Total monomeric anthocyanin (mg cyanidin-3-O-glucoside/100 g)^a
1	Castilla(1)*	Fresh(−1)	No(−1)	Conventional(−1)		32.50 ± 2.47
2	Castilla	Lyophilized(1)	No	Conventional		115.64 ± 0.13
3	Castilla	Fresh	Yes(1)	Conventional		37.79 ± 2.47
4	Castilla	Fresh	No	Ultrasound(1)		54.66 ± 5.46
5	Castilla	Fresh	Yes	Ultrasound		66.05 ± 0.05
6	Castilla	Lyophilized	Yes	Conventional		130.3 ± 12.70
7	Castilla	Lyophilized	No	Ultrasound		187.96 ± 11.28
8	Castilla	Lyophilized	Yes	Ultrasound		205.99 ± 21.87
9	Wild(−1)	Fresh	No	Conventional		38.55 ± 2.03
10	Wild	Lyophilized	No	Conventional		177.19 ± 11.37
11	Wild	Fresh	Yes	Conventional		41.19 ± 1.30
12	Wild	Fresh	No	Ultrasound		72.09 ± 1.64
13	Wild	Fresh	Yes	Ultrasound		78.49 ± 0.28
14	Wild	Lyophilized	Yes	Conventional		203.37 ± 8.57
15	Wild	Lyophilized	No	Ultrasound		394.53 ± 24.11
16	Wild	Lyophilized	Yes	Ultrasound		429.16 ± 2.44

*Numbers in parenthesis show independent variables in coded units. ^a mean ± standard deviation n = 3.

Table 2. Raw material characterization.

Parameter (n = 3)	Castilla blackberries (mean± standard deviation)	Wild blackberries (mean± standard deviation)
Equatorial diameter (mm)	20.91 ± 1.76^a	15.75 ± 1.05^b
Polar diameter (mm)	30.09 ± 2.50^a	20.36 ± 1.49^b
Moisture (%)	87.68 ± 0.45 ^a	85.25 ± 0.30 ^b
Total soluble solids of the pulp (°Brix)	7.83 ± 0.06^a	5.67 ± 0.6^b
pH of the pulp	3.07 ± 0.03^a	3.16 ± 0.09^a
Titratable acidity of the pulp (% citric acid)	1.88 ± 0.01^a	1.71 ± 0.01^b
Maturity index (°Brix per Titratable acidity)	4.16 ± 0.03^a	3.33 ± 0.02^b

^aEqual letters in a file means that there are no significant differences based on Tukey test, (p < 0.05).

Table 3. ANOVA and regression coefficients for the transformed model of the total monomeric anthocyanin content in blackberries extracts.

Parameter	Coefficient Estimate*	F Value	p-value Prob > F
Model	-	1108.83	< 0.0001
${\mathbf{X}}_1$ Variety	−0.19	498.32	< 0.0001
${\mathbf{X}}_2$ Type of Raw Material	0.71	6896.19	< 0.0001
${\mathbf{X}}_3$ Microwave Pretreatment	0.058	45.50	< 0.0001
${\mathbf{X}}_4$ Extraction Method	0.30	1243.79	< 0.0001
${\mathbf{X}}_1{\mathbf{X}}_2$	−0.10	142.89	< 0.0001
${\mathbf{X}}_1{\mathbf{X}}_4$	−0.050	33.92	< 0.0001
${\mathbf{X}}_2{\mathbf{X}}_4$	8.778x10^3	1.05	0.3125
${\mathbf{X}}_1{\mathbf{X}}_2{\mathbf{X}}_4$	−0.026	9.02	0.0046
Intercept	4.63
Lack of Fit test	-	0.74	0.6435
R^2	0.996
Adjusted R^2	0.995

*Those coefficients correspond to the model with the transformation: y’ = ln(y), the independent variables are in coded units.

Figure 1. Total monomeric anthocyanin content from blackberries extracts and its best conditions. A. Effect of variety, type of raw material and extraction method. B. Effect of microwave pretreatment.

Table 4. Blackberries extracts’ color in different pH.

pH	Castilla blackberry extract					Wild blackberry extract
	L	a*	b*	^aΔE	Color	L	a*	b*	^aΔE	Color
*	46.17	57.19	28.64			52.32	58.53	29.43
1.03	47.65	59.63	30.80	3.58		46.17	57.19	28.64	6.34
2.02	50.9	59.63	29.89	5.47		48.00	59.70	30.07	4.52
3.1	52.96	56.51	27.28	6.96		50.90	59.63	29.89	1.85
4.06	59.98	46.43	18.76	20.10		66.21	38.00	13.81	29.30
4.98	72.82	29.57	9.86	42.73		74.84	22.20	25.79	42.90
6.07	57.99	24.92	3.6	42.52		66.76	19.36	2.28	49.80
7.1	45.8	28.51	9.4	34.54		54.21	27.89	3.87	39.95
7.97	30.22	20.96	5.78	45.71		38.11	30.73	13.12	35.22
9.03	28.67	20.25	5.44	47.00		31.43	26.41	11.63	42.25
10.02	26.38	18.72	4.67	49.46		28.02	24.23	10.57	46.07
11.06	15.76	15.65	6.28	56.13		15.76	15.65	6.28	60.92
12.04	20.45	−23.45	24.78	84.73		22.60	−18.91	7.72	85.74
12.94	30.34	−23.69	26.7	82.44		39.46	−38.58	32.78	98.02

* Those parameters were determined to the pure extracts. ^aΔE values were calculated using the color parameters of the pure extracts as reference.

Table 5. pH determination of different substances from visual indicators.

Substance	pH (Potentiometer reading)	Universal Indicator Paper		Castilla blackberry extract		Wild blackberry extract
		Estimated pH	Color	Estimated pH	Color	Estimated pH	Color
Lime juice	2.52	2		2.02		2.02
White vinegar	2.84	3		3.1		3.1
Lemon juice	2.69	3		3.1		3.1
Peach syrup	3.56	3		4.06		4.06
Passion fruit juice	4.16	5		4.98		4.06
Cantaloupe juice	5.81	6		6.07		6.07
Water	6.97	7		7.1		7.1
Antiseptic alcohol	7.38	7		7.97		7.1
Sodium bicarbonate	8.43	8		7.97		9.03
Bleach	10.55	10		10.04		11.1