Nutritional and nutraceutical changes in blue corn (Zea mays) stored at different temperatures

Figures & data

Table 1. Pigmented (blue) maize genotypes selected for the study

Genotypes	Collection sites	Grain	Flour
AV=Azul Veracruz (Raza Tuxpeño)	Veracruz
AS= Azul Sinaloa (Raza Chalqueño x Elotes Cónicos)	Sinaloa
AP= Azul Poblano (Raza Chalqueño x Elotes Cónicos)	Puebla

Table 2. Content of proximal analysis (moisture, protein, carbohydrates, and starch) in genotypes of blue maize stored at different temperatures for 120 days

Proximal analysis	Time (days)	Temperature °C			Average
		6	25	35
Moisture (%)	0	12.36±0.55
	30	11.04±0.08 a A	10.43±0.10 a B	6.24±0.10 a C	9.24
	60	11.01±0.13 a A	10.21±0.08 ab B	5.56±0.05 b C	8.93
	90	11.01±0.24 a A	9.27±0.14 b B	4.66±0.15 c C	8.31
	120	11.00±0.22 a A	9.80±0.32 c B	4.10±0.05 d C	8.30
	Retention (%)	88.99	79.28	33.17	67.15
Protein (%)	0	10.67±0.14			10.67
	30	4.81±0.22 a C	5.52±0.15 a A	4.84±0.20 a B	5.06
	60	4.63±0.36 ab A	4.67±0.37 b A	4.66±0.21 a A	4.65
	90	4.64±0.12 ab B	4.69±0.30 bc AB	4.96±0.16 a A	4.76
	120	4.42±0.16 b B	4.36±0.18 c B	4.73±0.17 a A	4.50
	Retention (%)	41.42	40.86	44.33	42.20
Carbohydrates (%)	0	68.78±0.99			68.78
	30	76.43±0.43 a B	76.36±0.27 a B	81.28±0.22 a A	78.02
	60	74.74±0.42 b C	76.94±0.53 a B	81.04±0.30 ab A	77.57
	90	74.60±0.42 b C	76.61±0.64 a B	81.79±0.30 ab A	77.66
	120	74.37±0.54 b C	76.31±0.64 a B	81.27±0.50 b A	77.32
	Retention (%)	108.13	110.95	118.16	112.41
Starch (g/100g)	0	19.37±1.16			19.37
	30	19.29±1.32 c A	18.64±0.76 c A	17.39±0.37 a A	18.44
	60	19.17±0.61 c A	19.56±0.94 c A	19.63±0.75 a A	19.45
	90	32.52±0.98 b A	30.51±1.16 b A	29.90±1.29 b A	30.98
	120	41.89±1.55 a A	42.97±2.14 a A	32.46±1.40 b B	39.11
	Retention (%)	216.26	221.84	167.58	201.89

The values are the average of three repetitions. Means (n=3) ± standard deviation. Different letters within each column means that the treatments were statistically different Tukey (p≤0.05). Lower case letters compare times and upper-case letters compare temperatures. Retention % from 0 to 120 days.

Table 3. Total phenol content (free and bound) in genotypes of blue maize stored for 120 days at different temperatures

Phenols (mg GAE/100)	Time (days)	Temperature °C			Average
		6	25	35
Free	0	81.17±4.14			81.17
	30	83.60±2.13 a C	103.92±3.80 a B	129.22±5.58 a A	105.58
	60	78.65±2.30 b B	79.71±2.30 b B	94.59±3.16 b A	84.32
	90	69.93±3.33 c A	67.98±3.30 c A	58.31±2.33 c B	65.41
	120	65.32±2.82 d A	51.10±1.89 d B	40.19±2.65 d C	52.20
	Retention (%)	80.47	62.95	49.51	64.30
Bound	0	247.97±6.41			247.97
	30	247.91±5.84 a C	261.82±3.61 a B	286.86±5.95 a A	265.53
	60	241.31±5.89 a A	224.67±4.14 b B	203.35±4.91 b C	223.11
	90	227.04±4.54 b A	202.31±3.64 c B	162.63±7.08 c C	197.33
	120	216.21±4.83 c A	177.65±6.12 d B	128.54±6.60 d C	174.13
	Retention (%)	87.19	71.64	51.84	70.22

The values are the average of three repetitions. Means (n=3) ± standard deviation. Different letters within each column means that the treatments were statistically different Tukey (p≤0.05). Lower case letters compare times and upper-case letters compare temperatures. Retention % from 0 to 120 days.

Table 4. Total flavonoid content (free and bound) in genotypes of blue maize stored for 120 days at different temperatures

Flavonoids (mg CE/100 g)	Time (days)	Temperature °C			Average
		6	25	35
Free	0	18.78±1.21			18.78
	30	21.10±1.51 a B	23.57±1.45 a A	24.96±1.81 a A	23.21
	60	19.22±0.77 b A	16.92±1.17 b B	16.94±1.89 b B	17.69
	90	17.79±1.30 bc A	13.34±1.75 c B	10.74±1.40 c C	13.96
	120	17.22±1.04 c A	12.17±1.05 c B	7.69±1.13 d C	12.36
	Retention (%)	91.69	64.80	40.94	65.81
Bound	0	50.51±1.72			50.51
	30	55.47±2.63 a C	62.58±3.28 a B	65.53±3.55 a A	61.19
	60	50.99±2.21 b A	50.35±2.20 b A	44.22±2.03 b B	48.52
	90	46.73±0.70 c A	39.21±2.21 c B	26.86±2.80 c C	37.60
	120	45.13±0.69 c A	33.07±1.91 d B	18.63±2.14 d C	32.27
	Retention (%)	89.34	65.47	36.88	63.88

The values are the average of three repetitions. Means (n=3) ± standard deviation. Different letters within each column means that the treatments were statistically different Tukey (p≤0.05). Lower case letters compare times and upper-case letters compare temperatures. Retention % from 0 to 120 days.

Table 5. Total anthocyanin content and chromatic properties in blue maize genotypes stored for 120 days at different temperatures

	Time (days)	Temperature °C			Average
		6	25	35
L*	0	32.84±0.43
	30	33.85±0.32 a A	32.84±0.29 a B	32.48±1.12 b B	33.05
	60	33.48±1.01 a A	32.05±1.28 a C	34.71±0.73 a B	33.41
	90	33.21±0.75 a A	32.62±1.18 a B	30.99±0.69 c C	32.27
	120	33.09±0.57 a A	32.41±0.39 a B	29.38±0.65 d C	31.63
C*	0	2.07±0.20
	30	1.99±0.25 a B	2.07±0.44 a AB	2.84±0.49 a A	2.30
	60	1.85±0.12 a B	2.04±0.42 a B	3.04±0.49 a A	2.31
	90	1.72±0.11 a B	2.06±1.36 a B	2.57±0.40 b A	2.12
	120	1.70±0.36 a B	2.08±0.37 a AB	2.11±0.32 b A	1.96
h	0	84.69±0.23
	30	90.71±0.20 bc A	84.69±0.43 b B	81.72±0.49 bc B	85.71
	60	102.85±0.29 a A	85.71±0.42 ab B	84.36±0.49 b B	90.97
	90	94.79±0.58 b A	89.69±1.36 a B	89.73±0.40 a B	91.40
	120	96.61±0.30 b A	84.68±0.37 b B	84.63±0.32 b B	88.64
Anthocyanins (mg C3GE/100 g)	0	28.80±0.96
	30	27.36±1.87 a A	26.63±0.66 a A	23.42±0.37 a B	25.80
	60	23.14±0.72 b A	21.89±0.96 b B	19.23±0.62 b C	21.42
	90	21.80±0.69 bc A	19.40±0.95 c B	16.59±0.57 c C	19.26
	120	20.84±0.74 c A	16.34±0.99 d B	13.44±0.59 d C	16.87
	Retention (%)	72.36	56.74	46.67	58.58

The values are the average of three repetitions. Means (n=3) ± standard deviation. Different letters within each column means that the treatments were statistically different Tukey (p≤0.05). Lower case letters compare times and upper-case letters compare temperatures. % Retention from 0 to 120 days. L*: brightness; C*: color saturation; h: hue angle.

Table 6. Antioxidant capacity DPPH, ABTS and FRAP (free and bound) in genotypes of blue maize stored for 120 days at different temperatures

µmol TE/100 g	Time (days)	Temperature °C
		6		25		35
		Free	Bound	Free	Bound	Free	Bound
DPPH	0			596.42±10.47	797.53±11.53
	30	599.76±6.55a A	796.62±7.90 a A	591.06±7.76 a B	783.52±9.22 a B	572.03±4.88 a C	761.40±10.08 a C
	60	599.85±9.59 a A	785.77±11.25 ab A	576.22±6.80 b B	740.49±6.75 b B	549.51±4.37 b C	702.73±7.10 b C
	90	595.30±9.70 a A	778.65±15.05 b A	548.84±4.98 c B	697.50±8.65 c B	523.31±4.45 c C	652.25±7.72 c C
	120	595.07±8.26 a A	776.73±13.69 b A	519.55±5.32 d B	659.23±6.34 d B	494.75±4.72 d C	604.56±7.85 d C
	Retention (%)	99.81	97.39	87.11	82.65	82.95	75.80
ABTS	0			703.78±13.51	855.63±8.92
	30	703.13±10.98 a A	858.28±11.93 a A	689.22±11.48 a B	831.22±9.49 a B	653.75±11.59 a C	801.75±5.45 a C
	60	701.62±8.61 a A	853.39±13.56 a A	670.07±14.12 b B	802.07±10.10 b B	623.62±10.96 b C	763.29±3.61 b C
	90	694.80±7.53 ab A	841.45±10.69 b A	643.85±8.22 c B	776.74±7.24 c B	571.30±10.61 c C	728.43±6.24 c C
	120	681.00±7.09 b A	827.82±7.32 c A	596.70±8.27 d B	739.30±4.65 d B	546.34±16.49 d C	683.14±6.34 d C
	Retention (%)	96.76	96.75	84.78	86.40	77.63	79.84
FRAP	0			843.08±12.94	968.74±14.30
	30	842.64±12.91 a A	966.35±12.59 a A	824.90±10.77 a B	944.29±11.55 a B	799.77±5.61 a C	910.03±7.48 a C
	60	839.41±12.58 a A	959.08±12.98 a A	797.33±8.77 b B	902.9±6.69 b B	755.58±9.39 b C	857.89±10.59 b C
	90	830.63±12.51 ab A	942.35±14.19 b A	770.60±11.31 c B	855.18±10.94 c B	706.17±10.27 c C	802.22±8.65 c C
	120	823.26±13.00 b A	923.34±8.72 c A	725.57±8.82 d B	801.99±13.65 d B	662.63±10.2 d C	744.26±7.65 d C
	Retention (%)	97.65	95.31	86.06	82.79	78.60	76.83

The values are the average of three repetitions. Means (n=3) ± standard deviation. Different letters within each column means that the treatments were statistically different Tukey (p≤0.05). Lower case letters compare times and upper-case letters compare temperatures. Retention % from 0 to 120 days. DPPH= 2,2-diphenyl-1-picrylhydrazyl; ABTS= 2,2′azinobis (3-ethylbenzothiazoline-6-sulfonic acid); FRAP= Ferric Reducing Antioxidant Power.