Effect of thermal and non-thermal processing on antioxidant potential of cowpea seeds

Figures & data

Table 1. Effect of thermal and non-thermal processing on TPC (mg GAE/100 g) of cowpea cultivars.

		Thermal processing						Non-thermal processing
		Autoclave		Microwave		Boiling	Roasting	Soaking	Fermentation
Cultivars	Raw	15 min	30 min	15 min	30 min	90 min	45 min	6 h	16 h	24 h	32 h	40 h
EC-4216	147.3 ± 2.49^e	77.3 ± 5.23^b	106.9 ± 6.30^cd	69.9 ± 3.30^b	110.6 ± 1.39^d	50.7 ± 3.91^a	100.7 ± 5.99^c	99.7 ± 7.74^ab	156.4 ± 8.51^c	150.8 ± 6.25^c	108.0 ± 7.19^b	92.9 ± 9.04^a
		(47.48%)	(27.40%)	(52.53%)	(24.88%)	(65.54%)	(31.64%)	(32.29%)	(6.1%)	(2.4%)	(26.63%)	(36.93%)
BL-2	187.3 ± 3.29^d	68.8 ± 6.24^b	82.9 ± 3.50^c	47.6 ± 1.46^a	64.3 ± 1.04^b	49.2 ± 6.25^a	70.2 ± 2.32^b	86.0 ± 2.92^a	159.1 ± 4.02^c	153.5 ± 13.17^c	119.8 ± 7.34^b	96.5 ± 3.2^a
		(63.27%)	(55.70%)	(74.55%)	(65.65%)	(73.69%)	(62.47%)	(54.05%)	(15.06%)	(18.05%)	(36.01%)	(48.46%)
Kohinoor	113.3 ± 2.39^d	64.9 ± 1.99^b	82.9 ± 3.50^c	67.7 ± 5.45^b	125.4 ± 3.64^e	109.5 ± 1.66^d	55.2 ± 5.43^a	77.8 ± 3.00^a	160.7 ± 11.36^c	154.4 ± 31.86^c	99.2 ± 9.31^b	90.4 ± 2.50^b
		(42.73%)	(26.82%)	(40.21%)	(10.65%)	(3.36%)	(51.29%)	(31.34%)	(41.78%)	(36.16%)	(12.49%)	(20.26%)
Gomati	78.3 ± 0.47^e	13.4 ± 0.10^a	10.8 ± 0.64^a	23.0 ± 1.76^b	62.2 ± 5.74^d	36. ± 3.74^c	63.9 ± 4.19^d	51.9 ± 4.79^a	122.1 ± 8.86^e	104.1 ± 2.97^d	93.6 ± 9.90^cd	90.4 ± 2.50^c
		(82.82%)	(86.10%)	(70.52%)	(20.56%)	(53.48%)	(18.28%)	(33.63%)	(56.05%)	(33.02%)	(19.56%)	(15.46%)

All data are the mean ± SD of three replicates.

For each cowpea cultivars, means within a row not sharing a common letter differ significantly (p < 0.05).

Values given in bracket are percentage differences calculated from raw values.

Table 2. Effect of thermal and non-thermal processing on DPPH radical scavenging activity (%) of cowpea cultivars.

		Thermal processing						Non-thermal processing
		Autoclave		Microwave		Boiling	Roasting	Soaking	Fermentation
Cultivars	Raw	15 min	30 min	15 min	30 min	90 min	45 min	6 h	16 h	24 h	32 h	40 h
EC-4216	87.5 ± 4.5^abc	86.63 ± 1.80^ab	89.97 ± 1.80^bcd	84.33 ± 1.43^a	92.22 ± 0.44^d	91.54 ± 1.43^cd	93.44 ± 0.96^d	92.78 ± 0.67^b	94.20 ± 0.615^b	93.50 ± 0.5^b	92.82 ± 0.30^b	91.87 ± 0.40^b
		(0.99%)	(2.28%)	(3.62%)	(5.39%)	(4.61%)	(6.78%)	(6.03%)	(7.65%)	(6.85%)	(6.08%)	(4.99%)
BL-2	88.9 ± 4.8^b	94.56 ± 1.19^b	87.69 ± 1.19^ab	82.31 ± 1.43^a	91.44 ± 1.21^b	90.04 ± 3.64^b	90.86 ± 1.45^b	89.50 ± 2.81^ab	95.33 ± 0.42^c	94.88 ± 0.46^c	94.88 ± 0.46^c	93.53 ± 0.99b^c
		(6.36%)	(1.36%)	(7.41%)	(2.85%)	(1.28%)	(2.20%)	(0.67%)	(7.23%)	(6.72%)	(6.72%)	(5.20%)
Kohinoor	79.7 ± 2.9^a	87.02 ± 0.28^b	88.78 ± 0.28^b	85.71 ± 5.12^b	93.70 ± 2.17^c	94.04 ± 0.49^c	89.61 ± 1.9^bc	88.59 ± 0.93^b	94.15 ± 0.12^b	93.57 ± 0.18^b	92.80 ± 0.51^b	80.12 ± 10.07^a
		(9.18%)	(11.39%)	(7.54%)	(17.56%)	(17.99%)	(12.43%)	(11.15%)	(18.13%)	(17.40%)	(16.43%)	(0.52%)
Gomati	67.4 ± 1.92^a	87.15 ± 0.36^bc	89.22 ± 0.36^c	79.41 ± 7.01^b	91.71 ± 0.63^c	91.95 ± 0.95^c	89.48 ± 8.19^c	88.56 ± 0.46^c	77.11 ± 2.64^b	76.87 ± 3.41^b	69.36 ± 2.47^a	68.96 ± 3.67^a
		(29.30%)	(32.37%)	(17.81%)	(36.06%)	(36.42%)	(32.75%)	(31.39%)	(14.40%)	(14.05%)	(2.90%)	(2.31%)

All data are the mean ± SD of three replicates.

For each cowpea cultivars, means within a row not sharing a common letter differ significantly (p < 0.05).

Values given in bracket are percentage differences calculated from raw values.

Table 3. Effect of thermal and non-thermal processing on FRAP (mmol Fe (II) Eq/g) of cowpea cultivars.

		Thermal processing						Non-thermal processing
		Autoclave		Microwave		Boiling	Roasting	Soaking	Fermentation
Cultivars	Raw	15 min	30 min	15 min	30 min	90 min	45 min	6 h	16 h	24 h	32 h	40 h
EC-4216	7.89 ± 0.62^e	3.47 ± 0.03^c	3.64 ± 0.07^c	3.02 ± 0.08^b	2.72 ± 0.07^ab	2.48 ± 0.07^a	4.84 ± 0.05^d	1.58 ± 0.05^a	8.10 ± 0.16^b	8.20 ± 0.15^b	8.463 ± 0.23^b	8.94 ± 0.27^c
		(56.02%)	(53.86%)	(61.72%)	(65.52%)	(68.56%)	(38.65%)	(79.97%)	(2.66%)	(3.92%)	(7.22%)	(13.30%)
BL-2	6.79 ± 0.36^e	3.34 ± 0.04^c	3.43 ± 0.16^c	2.72 ± 0.07^b	1.98 ± 0.08^a	2.56 ± 0.2^b	4.81 ± 0.11^d	1.49 ± 0.03^a	8.079 ± 0.11^c	8.137 ± 0.11^c	8.404 ± 0.19^cd	8.71 ± 0.10^d
		(50.81%)	(49.48%)	(59.94%)	(70.83%)	(62.29%)	(29.16%)	(78.05%)	(18.98%)	(19.83%)	(23.71%)	(28.27%)
Kohinoor	7.36 ± 0.32^f	3.25 ± 0.37^cd	3.45 ± 0.25^d	2.88 ± 0.03^b	2.82 ± 0.01^b	2.01 ± 0.13^a	4.37 ± 0.08^e	1.79 ± 0.005^a	7.788 ± 0.36^b	7.813 ± 0.24^b	8.362 ± 0.13^c	8.507 ± 0.22^c
		(55.84%)	(53.12%)	(60.86%)	(61.68%)	(72.69%)	(40.62%)	(75.67%)	(5.81%)	(6.15%)	(13.61%)	(15.58%)
Gomati	5.09 ± 0.20^e	3.32 ± 0.05^c	3.28 ± 0.14^c	2.62 ± 0.03^b	1.90 ± 0.14^a	2.08 ± 0.06^a	3.54 ± 0.15^d	0.99 ± 0.06^a	7.602 ± 0.20^c	7.797 ± 0.16^cd	7.787 ± 0.26^cd	8.00 ± 0.17^d
		(34.77%)	(35.55%)	(48.52%)	(62.67%)	(59.13%)	(30.54%)	(80.55%)	(49.31%)	(53.04%)	(52.84%)	(57.17%)

All data are the mean ± SD of three replicates.

For each cowpea cultivars, means within a row not sharing a common letter differ significantly (p < 0.05).

Values given in bracket are percentage differences calculated from raw values.

Table 4. Effect of thermal and non-thermal processing on total flavonoid content (TFC) (mg QE/g) of cowpea cultivars.

		Thermal processing						Non-thermal processing
		Autoclave		Microwave		Boiling	Roasting	Soaking	Fermentation
Cultivars	Raw	15 min	30 min	15 min	30 min	90 min	45 min	6 h	16 h	24 h	32 h	40 h
EC-4216	1.026 ± 0.04^e	0.18 ± 0.032^a	0.45 ± 0.01^b	0.68 ± 0.050^c	0.83 ± 0.040^d	0.54 ± 0.09^b	0.76 ± 0.08^cd	0.42 ± 0.02^b	0.54 ± 0.02^c	0.41 ± 0.03^b	0.33 ± 0.036^a	0.31 ± 0.03^a
		(82.45%)	(56.14%)	(33.72%)	(19.10%)	(47.36%)	(25.92%)	(59.06%)	(47.36%)	(60.03%)	(67.83%)	(69.78%)
BL-2	0.842 ± 0.012^e	0.173 ± 0.09^a	0.413 ± 0.045^b	0.531 ± 0.02^c	0.649 ± 0.06^d	0.506 ± 0.01^c	0.59 ± 0.04^cd	0.5 ± 0.05^b	0.68 ± 0.05^c	0.51 ± 0.02^b	0.49 ± 0.02^b	0.35 ± 0.06^a
		(79.45%)	(50.95%)	(36.93%)	(22.92%)	(39.90%)	(29.92%)	(40.61%)	(19.2%)	(39.42%)	(41.80%)	(58.43%)
Kohinoor	0.981 ± 0.015^f	0.24 ± 0.019^a	0.368 ± 0.05^b	0.632 ± 0.08^cd	0.777 ± 0.09^e	0.54 ± 0.02^c	0.673 ± 0.07^d	0.71 ± 0.06^c	0.82 ± 0.04^d	0.75 ± 0.07^cd	0.62 ± 0.014^b	0.48 ± 0.015^a
		(75.53%)	(62.48%)	(35.57%)	(20.79%)	(44.95%)	(31.39%)	(27.62%)	(16.41%)	(23.54%)	(36.79%)	(51.07%)
Gomati	1.053 ± 0.02^e	0.18 ± 0.02^a	0.18 ± 0.01^a	0.69 ± 0.02^c	0.83 ± 0.02^d	0.59 ± 0.03^b	0.70 ± 0.01^c	0.49 ± 0.04^c	0.64 ± 0.015^d	0.46 ± 0.011^bc	0.44 ± 0.03^ab	0.41 ± 0.02^a
		(82.90%)	(82.90%)	(34.47%)	(21.17%)	(43.96%)	(33.52%)	(53.46%)	(39.22%)	(56.31%)	(58.21%)	(61.06%)

All data are the mean ± SD of three replicates.

For each cowpea cultivars, means within a row not sharing a common letter differ significantly (p < 0.05).

Values given in bracket are percentage differences calculated from raw values.

Table 5. Correlation between antioxidant activity and total phenolic content and total flavonoid content of thermal processing of cowpea cultivars.

	TPC							TFC
	Raw	A15	A30	M15	M30	Boil	Roast	Raw	A15	A30	M15	M30	Boil	Roast
DPPH	0.936	0.246	0.062	0.979	0.888	0.792	0.974	−0.644	−0.415	−0.032	−0.099	0.203	0.384	0.482
FRAP	0.573	0.354	0.912	0.932	0.993	0.497	0.538	−0.213	0.656	0.877	−0.208	0.392	−0.678	0.145

Table 6. Correlation between antioxidant activity and total phenolic content and total flavonoid content of non-thermal processing of cowpea cultivars.

	TPC						TFC
	Raw	Soak	F16	F24	F32	F40	Raw	Soak	F16	F24	F32	F40
DPPH	0.936	0.785	0.993	0.996	0.726	0.817	−0.644	−0.649	0.169	0.306	0.169	−0.653
FRAP	0.573	0.734	0.753	0.557	0.701	0.587	−0.213	0.503	−0.383	−0.560	0.034	−0.590