High-performance liquid chromatography-diode array detector determination and availability of phenolic compounds in 10 genotypes of walnuts

Figures & data

Figure 1. Tehama variety chromatogram which identifies:(1) gallic acid, (2) gallocatechin, (3) catechin, (4) procyanidin B₂, (5) gallate epigallocatechin, (6) epicatechin and (7) gallate epicatechin at 280 nm. (8) syringic acid, (9) chlorogenic acid and (10) p-coumaric acid at 320 nm and (11) ellagic acid identified at 360 nm.

Table 1. Flavonoid phenolic compounds quantified in the different genotypes of walnuts.

	Catechin**	Epicatechin*	Gallate epicatechin*	Gallocatechin*	Gallate epigallocatechin*	Procyanidin B2**
Algaida	17.86 ± 0.05^b	365.67 ± 4.41^b,c	160.53 ± 3.69^c,d,e	166.65 ± 12.44^a,b	83.33 ± 5.72^a,b	19.83 ± 2.37^a,b
Amigo	20.02 ± 0.06^a	366.83 ± 7.78^b,c	179.58 ± 2.97^a,b	155.62 ± 13.18^b,c	65.32 ± 19.22^b,c,d	17.35 ± 1.19^b,c
Chico	14.87 ± 1.01^c,d	353.07 ± 4.59^d	148.25 ± 3.63^e,f	164.62 ± 13.58^a,b	31.31 ± 0.72^g	14.61 ± 0.24^c,d
Eureka	12.32 ± 0.11^e	390.55 ± 1.16^a	183.75 ± 1.10^a	139.06 ± 3.27^c	42.02 ± 6.44^e,f	13.19 ± 0.55^d,e
Franquette	10.92 ± 0.03^e	351.52 ± 11.07^d	170.49 ± 3.05^a,b,c	183.58 ± 4.26^a	80.88 ± 6.89^a,b	14.10 ± 0.74^c,d
Payne	16.93 ± 0.21^b,c	375.17 ± 1.61^a,b	157.16 ± 3.29^d,e,f	177.15 ± 3.44^a,b	87.48 ± 3.66^a	19.19 ± 1.40^a,b
Pedro	11.89 ± 1.29^e	362.48 ± 4.67^b,c	139.41 ± 2.93^f	167.52 ± 8.78^a,b	77.06 ± 2.13^a,b,c	20.78 ± 0.80^a
Serr	11.48 ± 0.82^e	350.15 ± 5.01^d	144.69 ± 2.09^e,f	157.35 ± 1.97^b,c	48.99 ± 2.78^d,e,f	14.22 ± 1.21^c,d
Sunland	19.92 ± 0.37^a	369.72 ± 15.74^a,b,c	181.88 ± 1.36^a	164.36 ± 0.57^a,b	40.98 ± 2.52^e,f	11.01 ± 0.61^e
Tehama	15.05 ± 1.12^c	374.35 ± 4.17^a,b	190.72 ± 0.56^a	161.17 ± 8.93^a,b,c	59.46 ± 2.89^c,d,e	15.19 ± 0.68^c,d

**Results expressed as mg/100 g of walnut (mean ± SD).

*Results expressed as µg/100 g of walnut (mean ± SD).

Figure 2. Availability of flavonoid compounds identified after “in vitro” digestion. *Indicates statistical differences (p < 0.05).

Table 2. Phenolic acids quantified in the different genotypes of walnuts.

	Gallic acid**	Ellagic acid**	Syringic acid**	Chlorogenic acid**	p-Coumaric acid*
Algaida	16.39 ± 1.38^b,c	50.77 ± 9.05^a,b	38.01 ± 1.91^a,b	7.01 ± 0.75^a,b	214.11 ± 7.49^a,b,c
Amigo	11.73 ± 0.80^e	23.76 ± 1.23^c	21.30 ± 1.22^c,d	4.32 ± 0.95^a,b,c	167.60 ± 2.82^c,d
Chico	16.16 ± 1.12^b,c	33.31 ± 4.62^b,c	27.73 ± 1.33^b,c,d	2.42 ± 0.73^c	155.00 ± 20.52^c,d
Eureka	16.53 ± 1.76^b,c	70.47 ± 1.90^a	44.59 ± 5.72^a	4.97 ± 2.37^a,b,c	219.73 ± 16.93^a,b,c
Franquette	15.05 ± 1.30^b,c,d	44.69 ± 10.05^b,c	20.77 ± 0.59^c,d	4.80 ± 1.28^a,b,c	173.67 ± 51.13^c,d
Payne	11.58 ± 0.8^e	52.57 ± 14.89^a,b	27.82 ± 7.15^b,c,d	7.82 ± 1.62^a	179.78 ± 8.43^c,d
Pedro	13.34 ± 0.87^d,e	36.68 ± 5.10^b,c	33.44 ± 1.57^a,b,c	5.29 ± 1.07^a,b,c	146.51 ± 13.25^d
Serr	17.55 ± 1.94^b	21.73 ± 2.16^c	18.74 ± 0.78^d	5.61 ± 2.05^a,b,c	203.30 ± 18.33^b,c,d
Sunland	13.77 ± 1.33^b,c,d	56.31 ± 11.83^a,b	41.16 ± 1.05^a,b	3.75 ± 1.09^b,c	260.66 ± 18.04^a,b
Tehama	21.92 ± 1.67^a	69.18 ± 10.49^a	15.19 ± 0.95^d	2.75 ± 0.66^c	273.21 ± 27.92^a

**Results expressed as mg/100 g of walnut (mean ± SD).

*Results expressed as µg/100 g of walnut (mean ± SD)

Table 3. Flavonoid phenolic compounds quantified in the dialyzed fraction of the different genotypes of walnuts.

	Catechin**	Epicatechin*	Gallate epicatechin*	Gallocatechin*	Gallate epigallocatechin*	Procyanidin B2**
Algaida	7.51 ± 0.02^a,b	84.10 ± 1.01^d	57.79 ± 1.33^b	71.66 ± 5.35^c	42.50 ± 2.92^a	8.13 ± 0.97^a
Amigo	8.20 ± 0.02^a	91.71 ± 1.95^c	61.06 ± 1.01^a	98.04 ± 8.30^a	34.62 ± 10.19^a,b	6.59 ± 0.45^b
Chico	6.54 ± 0.44^c	45.90 ± 0.60^g	45.96 ± 1.13^d	69.14 ± 5.70^c	12.21 ± 0.28^e	3.65 ± 0.06^c,d
Eureka	1.48 ± 0.01^e	54.68 ± 0.16^f	40.42 ± 0.24^e	57.01 ± 1.34^d	15.55 ± 2.38^d,e	3.82 ± 0.16^c,d
Franquette	5.13 ± 0.01^d	133.58 ± 4.21^b	28.98 ± 0.52^f	71.60 ± 1.66^c	29.12 ± 2.48^b,c	3.81 ± 0.20^c,d
Payne	6.59 ± 0.08^c	67.53 ± 0.29^e	53.43 ± 1.12^c	62.00 ± 1.20^c,d	35.87 ± 1.50^a,b	4.80 ± 0.35^c
Pedro	4.76 ± 0.52^d	148.62 ± 1.91^a	20.91 ± 0.44^h	72.03 ± 3.70^c	23.89 ± 0.66^c,d	2.91 ± 0.11^d
Serr	6.31 ± 0.45^c	66.53 ± 0.95^e	28.94 ± 0.42^f	26.75 ± 0.33^e	20.57 ± 1.17^c,d,e	4.55 ± 0.39^c
Sunland	6.97 ± 0.13^b,c	144.19 ± 6.14^a	23.64 ± 0.18^g	83.82 ± 0.30^b	11.06 ± 0.68^e	3.85 ± 0.21^c,d
Tehama	5.42 ± 0.40^d	33.69 ± 0.38^h	24.79 ± 0.07^g	62.85 ± 3.48^c d	10.70 ± 0.52^e	4.10 ± 0.18^c

**Results expressed as mg/100 g of walnut (mean ± SD).

*Results expressed as µg/100 g of walnut (mean ± SD).

Figure 3. Availability of non-flavonoid compounds identified after “in vitro” digestion. *Indicates statistical differences (p < 0.05) with ellagic acid and syringic acid.

Table 4. Phenolic acids quantified in the dialyzed fraction of the different genotypes of walnuts.

	Gallic acid**	Ellagic acid**	Syringic acid**	Chlorogenic acid**	p-Coumaric acid*
Algaida	6.89 ± 0.58^a	16.25 ± 2.90^a	7.60 ± 0.38^b,c	1.89 ± 0.20^a,b	55.67 ± 1.95^b
Amigo	5.75 ± 0.39^b	9.03 ± 0.47^b	3.41 ± 0.20^d	1.34 ± 0.29^b,c	36.87 ± 0.62^c,d,e
Chico	6.46 ± 0.45^a,b	9.66 ± 1.34^b	5.82 ± 2.38^c,d	0.46 ± 0.14^d	35.65 ± 4.72^c,d,e
Eureka	5.62 ± 0.60^b	14.80 ± 0.40^a	4.46 ± 0.57^d	0.99 ± 0.47^b,c	103.27 ± 7.96^a
Franquette	2.86 ± 0.25^c,d,e	4.92 ± 1.11^c,d	4.99 ± 0.14^c,d	1.63 ± 0.44^a,b	33.00 ± 9.71^d,e
Payne	2.55 ± 0.18^d,e	5.26 ± 1.49^c,d	6.12 ± 1.57^b,c,d	2.43 ± 0.50^a	48.54 ± 2.28^b,c
Pedro	2.27 ± 0.15^d,e	4.40 ± 0.61^c,d	8.70 ± 0.41^b	1.96 ± 0.40^a,b	23.44 ± 2.12^e
Serr	3.86 ± 0.43^c	2.82 ± 0.28^d	5.25 ± 0.22^c,d	0.96 ± 0.35^b,c	44.73 ± 4.03^b,c,d
Sunland	1.93 ± 0.19^e	5.07 ± 1.06^c,d	12.76 ± 0.33^a	1.65 ± 0.48^a,b	36.49 ± 2.53^c,d,e
Tehama	3.29 ± 0.25^c,d	7.61 ±1.15^b,c	4.10 ± 0.26^d	0.94 ± 0.22^b,c	40.98 ± 4.19^c,d

**Results expressed as mg/100 g of walnut (mean ± SD).

*Results expressed as µg/100 g of walnut (mean ± SD).