Instrumental texture and flavonoid profile of paste developed from sprouted onion varieties of Indian origin

Figures & data

Figure 1. Images of raw and sprouted onion varieties: PWR: Punjab White raw; PNR: Punjab Naroya raw; PRO 6 R: PRO 6 raw; CMR: commercial raw; PWS: Punjab White sprouted; PNS: Punjab Naroya sprouted; PRO 6 S: PRO 6 sprouted; and CMS: commercial sprouted.

Table 1. Effect of sprouting on physic-chemical composition of paste of four onion varieties.

	Punjab White		Punjab Naroya		PRO-6		Commercial
	Raw	Sprouted	Raw	Sprouted	Raw	Sprouted	Raw	Sprouted
pH	4.03 ± 0.02^aP	3.89 ± 0.11^BCP	4.01 ± 0.11^aP	3.81 ± 0.10^CP	4.05 ± 0.04^aP	4.01 ± 0.01^ABP	4.06 ± 0.04^aP	4.09 ± 0.02^AP
Acidity (%)	0.34 ± 0.02^aP	0.40 ± 0.18^BP	0.35 ± 0.05^aP	0.47 ± 0.04^AP	0.32 ± 0.04^aP	0.37 ± 0.03^DP	0.31 ± 0.02^aP	0.25 ± 0.06^CP
TSS (°B)	21.03 ± 0.50^bP	16.01 ± 1.50^BP	24.04 ± 0.50^aP	23.01 ± 1.50^AP	21.50 ± 1.50^bP	16.50 ± 1.30^BQ	23.00 ± 1.32^abP	18.02 ± 2.50^BQ
TS (%)	22.46 ± 0.84^bP	20.00 ± 0.87^BP	26.02 ± 0.50^aP	25.20 ± 1.81^AP	22.7 ± 1.76^bP	20.73 ± 0.89^BP	25.0 ± 1.32^aP	21.02 ± 1.0^BQ
NaCl (%)	9.03 ± 0.75^aP	8.43 ± 0.92^AP	9.75 ± 0.15^bP	9.70 ± 0.43^DP	9.13 ± 0.15^dP	8.85 ± 0.22^BP	9.56 ± 1.04^cP	9.00 ± 0.50^CP
Water activity	0.77 ± 0.02^cQ	0.88 ± 0.09^AP	0.72 ± 0.03^dQ	0.82 ± 0.09^CP	0.75 ± 0.04^aQ	0.87 ± 0.11^DP	0.74 ± 0.17^bQ	0.84 ± 0.05^BP
Moisture (%)	69.72 ± 0.37^aQ	70.58 ± 0.87^AP	67.91 ± 0.87^cQ	68.71 ± 0.59^CP	69.34 ± 1.31^dQ	70.23 ± 1.72^BP	68.20 ± 0.93^bQ	69.83 ± 0.97^DP

Results are expressed as mean values ± standard deviations. Means in a row with same superscripts (a, b, c, d) for raw and (A, B, C, D) for sprouted are not significantly different (P < 0.05). Means in a row with same superscripts (P, Q) within a particular variety are not significantly different (P < 0.05).

Table 2. Effect of sprouting on colour and particle size of paste of four onion varieties.

		Punjab White		Punjab Naroya		PRO-6		Commercial
		Raw	Sprouted	Raw	Sprouted	Raw	Sprouted	Raw	Sprouted
Colour	L* value	56.70 ± 0.44^aP	51.90 ± 0.20^AQ	54.00 ± 0.36^bP	48.83 ± 0.31^BQ	40.43 ± 0.42^dP	38.60 ± 0.36^DQ	45.47 ± 0.35^cP	44.80 ± 0.22^CP
	a value	–2.50 ± 0.40^dQ	–0.63 ± 0.31^DP	2.10 ± 0.20^cQ	2.83 ± 0.31^CP	9.70 ± 0.36^aQ	14.03 ± 0.15^AP	9.03 ± 0.15^bQ	13.40 ± 0.37^BP
	b value	8.40 ± 0.26^aP	8.80 ± 0.36^AP	5.03 ± 0.15^aQ	8. 05 ± 0.61^BP	0.13 ± 0.06^cQ	3.70 ± 0.30^DP	4.07 ± 0.21^bP	4.50 ± 0.30^CP
Particle size	Median	701.45 ± 17.99^aP	635.45 ± 25.46^AQ	609.98 ± 17.79^bP	580.28 ± 48.13^AP	682.78 ± 33.55^aP	663.69 ± 45.45^AP	724.24 ± 34.78^aP	620.93 ± 58.45^AP
	Mean	686.57 ± 20.07^aP	620.28 ± 73.68^AP	558.87 ± 49.16^bP	553.53 ± 33.14^AP	667.45 ± 25.08^aP	633.26 ± 66.03^AP	690.08 ± 22.83^aP	594.04 ± 57.31^AP
	Modal	675.33 ± 31.48^bP	675.33 ± 31.48^AP	675.33 ± 31.48^bP	675.33 ± 31.48^AP	675.33 ± 31.48^bP	675.33 ± 31.48^AP	675.33 ± 31.48^bP	675.33 ± 31.48^AP
	Q3 (10%)	472.60 ± 16.64^aP	472.60 ± 16.64^AP	293.62 ± 29.11^bQ	372.52 ± 28.66^BCP	472.60 ± 16.64^aP	419.58 ± 34.08^ABP	472.60 ± 16.64^aP	419.58 ± 34.08^ABP
	Q3 (90%)	965.40 ± 26.45^aP	760.61 ± 24.06^BQ	856.81 ± 43.95^bP	760.61 ± 24.06^BQ	965.40 ± 26.45^aP	965.40 ± 26.45^AP	965.40 ± 26.45^aP	760.61 ± 24.06^BQ

Results are expressed as mean values ± standard deviations. Means in a row with same superscripts (a, b, c, d) for raw and (A, B, C, D) for sprouted are not significantly different (P < 0.05). Means in a row with same superscripts (P, Q) within a particular variety are not significantly different (P < 0.05).

Figure 2. Microscopic pictures of onion paste with a magnification of 100× obtained for: (a) paste from Punjab White raw onion variety; (b) paste from Punjab White sprouted onion variety.

Table 3. Effect of sprouting on phenolic content, antioxidant activity, and textural characteristics of paste of four onion varieties.

	Punjab White		Punjab Naroya		PRO-6		Commercial
	Raw	Sprouted	Raw	Sprouted	Raw	Sprouted	Raw	Sprouted
TPC (mg/g)	3.45 ± 0.09^cQ	4.79 ± 0.22^BP	4.60 ± 0.23^aQ	5.00 ± 0.06^ABP	4.78 ± 0.14^aQ	5.23 ± 0.11^AQ	4.18 ± 0.13^bP	4.43 ± 0.25^CP
TFC (mg /g)	2.27 ± 0.04^cQ	2.64 ± 0.21^BP	2.75 ± 0.05^bQ	2.96 ± 0.12^BP	3.46 ± 0.17^aP	3.72 ± 0.40^AP	2.35 ± 0.12^cP	2.48 ± 0.17^BP
Total antioxidant capacity (mg/g)	5.14 ± 0.05^dQ	5.85 ± 0.05^BP	6.38 ± 0.41^bP	6.76 ± 0.79^ABP	7.14 ± 0.03^aP	7.69 ± 0.55^AP	5.87 ± 0.10^cP	5.93 ± 0.23^BP
DPPH (%)	21.18 ± 0.18^dQ	26.71 ± 1.53^BP	41.67 ± 0.71^bQ	51.84 ± 1.92^BP	48.35 ± 0.13^aP	64.52 ± 1.30^AP	22.98 ± 1.48^cQ	27.56 ± 1.43^CP
Firmness (g)	356.88 ± 9.69^cP	194.62 ± 1.76^DQ	407.87 ± 3.03^bP	313.47 ± 2.91^BQ	520.28 ± 5.26^aP	323.90 ± 9.0^AQ	363.007 ± 3.14^cP	260.66 ± 3.97^CQ
Adhesiveness (g-s)	–2593.48 ± 6.47^aP	–755.84 ± 9.07^CQ	–895.90 ± 9.75^bP	–604.11 ± 1.36^DQ	–788.07 ± 24.88^cQ	–545.34 ± 10.93^BP	–954.65 ± 10.06^cQ	–538.837 ± 13.39^AP
Cohesiveness	0.28 ± 0.02^cP	0.54 ± 0.11^AQ	0.39 ± 0.01^bQ	0.58 ± 0.05^AP	0.53 ± 0.05^aP	0.60 ± 0.03^AP	0.35 ± 0.07^bcQ	0.57 ± 0.04^AP
Springiness	82.75 ± 2.01^bP	97.55 ± 2.07^AQ	92.88 ± 1.95^aP	94.17 ± 2.84^AP	54.19 ± 3.08^cQ	97.87 ± 2.15^AP	94.107 ± 1.21^aP	97.16 ± 3.50^AP
Gumminess	102.53 ± 1.55^dQ	116.70 ± 2.50^DP	123.84 ± 1.86^cQ	142.68 ± 2.66^CP	186.88 ± 3.09^aP	221.21 ± 5.23^BQ	187.14 ± 1.21^bQ	217.43 ± 2.66^AP
Chewiness	84.65 ± 1.83^dQ	113.85 ± 2.64^DP	115.07 ± 3.65^cQ	133.59 ± 2.27^CP	155.15 ± 3.50^bQ	182.91 ± 2.46^BP	181.59 ± 1.59^aQ	204.75 ± 1.64^AP

Results are expressed as mean values ± standard deviations. Means in a row with same superscripts (a, b, c, d) for raw and (A, B, C, D) for sprouted are not significantly different (P < 0.05). Means in a row with same superscripts (P, Q) within a particular variety are not significantly different (P < 0.05).

Table 4. Effect of sprouting on flavonoid profile of paste of four onion varieties (mg/kg).

	Punjab White		Punjab Naroya		PRO-6		Commercial
Flavonoids	Raw	Sprouted	Raw	Sprouted	Raw	Sprouted	Raw	Sprouted
Quercetin	125.03 ± 1.76^cP	123.90 ± 4.00^CP	193.60 ± 0.80^bQ	212.40 ± 1.80^BP	220.30 ± 3.00^aQ	288.10 ± 2.90^AP	69.50 ± 1.39^dQ	73.20 ± 1.95^DP
Kaempferol	5.10 ± 0.90^bP	4.20 ± 0.47^DQ	10.90 ± 1.61^aP	5.20 ± 0.40^CQ	14.50 ± 0.75^aQ	18.20 ± 0.72^AP	12.30 ± 2.55^aP	8.10 ± 0.35^BQ
Myricetin	29.20 ± 1.28^bP	28.60 ± 2.83^BP	31.40 ± 3.00^abQ	40.30 ± 2.31^AP	36.68 ± 4.60^aP	41.40 ± 3.14^AP	27.90 ± 2.71^bP	26.80 ± 1.80^BP
Quercetin-3′-glucoside	1.04 ± 0.06^cP	0.90 ± 0.01^CQ	2.90 ± 0.40^bP	2.80 ± 0.38^BP	3.16 ± 0.31^bQ	4.50 ± 0.32^AP	2.40 ± 0.30^aP	2.60 ± 0.20^BP
Quercetin-4′-glucoside	52.01 ± 2.19^bP	41.50 ± 1.43^BQ	40.70 ± 2.50^cP	42.10 ± 1.08^BP	85.10 ± 2.57^aP	88.00 ± 2.85^AP	37.40 ± 1.82^cP	36.90 ± 2.22^CP
Total flavonoids	212.37 ± 2.76^cP	199.10 ± 2.14^CQ	279.50 ± 5.3^bQ	302.80 ± 2.66^BP	359.80 ± 5.52^aQ	440.20 ± 7.94^AP	149.50 ± 3.50^dP	147.60 ± 2.45^DP

Results are expressed as mean values ± standard deviations. Means in a row with same superscripts (a, b, c, d) for raw and (A, B, C, D) for sprouted are not significantly different (P < 0.05). Means in a row with same superscripts (P, Q) within a particular variety are not significantly different (P < 0.05).

Figure 3. The typical representation of HPLC chromatograms obtained for: (a) Punjab Naroya raw onion variety; (b) Punjab Naroya sprouted onion variety (1: quercetin-3-glucoside; 2: quercetin-4-glucoside; 3: quercetin; 4: myricetin; 5: kaempferol).