Comparison of some physical and chemical characteristics of buckwheat (Fagopyrum esculentum Moench) grains

Figures & data

Table 1. Size distribution of buckwheat grains based on length (L), width (W) and thickness (T).

Tabla 1. Distribución del tamaño de los granos de trigo sarraceno en base a la alargada (L), la anchura (W) y el espesor (T).

	Size category
Samples	Ungraded	Small	Medium	Large
Length (L)
Commercial buckwheat	3.11–4.55 (100)	3.11–3.59 (26)	3.60–4.07 (57)	4.08–4.55 (17)
Güneş variety	4.90–7.33 (100)	4.90–5.71 (21)	5.72–6.52 (57)	6.53–7.33 (22)
Width (W)
Commercial buckwheat	2.73–4.22 (100)	2.73–3.23 (30)	3.24–3.74 (63)	3.75–4.22 (7)
Güneş variety	2.20–4.90 (100)	2.20–3.67 (31)	3.68–4.28 (58)	4.29–4.90 (11)
Thickness (T)
Commercial buckwheat	2.43–3.82 (100)	2.43–2.89 (12)	2.90–3.35 (71)	3.36–3.82 (17)
Güneş variety	2.87–4.52 (100)	2.87–3.42 (49)	3.43–3.97 (51)	3.98–4.52 (3)

Range and frequency (%) in parenthesis.

Rango y frecuencia (%) en paréntesis.

Figure 1. Frequency distribution curves of buckwheat grain dimensions: (a) commercial buckwheat; (b) Güneş variety.

Figura 1. Curvas de distribución de frecuencia de las dimensiones de las dimensiones de los granos de trigo sarraceno: (a) trigo sarraceno comercial; (b) variedad Güneş.

Table 2. Physical and mechanical characteristics of buckwheat grains.

Tabla 2. Características físicas y mecánicas de los granos de trigo sarraceno.

Characteristics	Number of replications	Commercial buckwheat	Güneş variety
Moisture (d.b.)	3	6.46 ± 0.26 b	9.46 ± 0.36 a
Length (mm)	100	3.80 ± 0.28 b	6.14 ± 0.49 a
Width (mm)	100	3.36 ± 0.27 b	3.87 ± 0.35 a
Thickness (mm)	100	3.14 ± 0.26 b	3.46 ± 0.26 a
Arithmetic mean diameter (mm)	100	3.43 ± 0.22 b	4.49 ± 0.29 a
Geometric mean diameter (mm)	100	3.41 ± 0.23 b	4.34 ± 0.28 a
Sphericity (%)	100	89.94 ± 4.98 a	70.79 ± 4.46 b
Aspect ratio (%)	100	88.50 ± 7.02 a	63.25 ± 6.44 b
Seed volume (mm^3)	100	21.19 ± 4.29 b	43.44 ± 8.48 a
Surface area (cm^2)	100	36.78 ± 4.91 b	59.33 ± 7.70 a
1000-grain weight (g)	20	19.98 ± 1.21 Ns	21.74 ± 0.81 Ns
Bulk density (kg/m^3)	20	833.7 ± 48.4 a	598.6 ± 27.5 b
True density (kg/m^3)	20	1269.3 ± 138.5 a	1077.1 ± 94.2 b
Porosity (%)	20	33.9 ± 3.9 b	44.2 ± 3.3 a
Rupture force (N)	20	27.59 ± 1.33 a	18.72 ± 1.84 b
Angle of repose (^o)	20	22.03 ± 1.85 b	25.47 ± 1.51 a
Terminal velocity (m/s)	20	2.98 ± 0.48 Ns	3.11 ± 0.45 Ns
Coefficient of static friction on
Rubber	20	0.462 ± 0.022 A	0.474 ± 0.022 A
Aluminium	20	0.431 ± 0.023 B	0.442 ± 0.031 B
Stainless steel	20	0.396 ± 0.023 Cb	0.438 ± 0.035 Ba

Different letter in the same line indicate significant differences (P < 0.05).

Letters a and b indicate the statistical difference in rows.

Letters A–C indicate the statistical difference in columns for coefficient of static friction.

Ns: Not significant

Las distintas letras en la misma línea indican diferencias significativas (P < 0,05).

Las letras a y b indican diferencias estadísticas en las filas.

Las letras A–C indican diferencias estadísticas en las columnas para el coeficiente de fricción estática.

Ns: No es significativo

Table 3. Correlation coefficients among seed dimensions (L, W and T), sphericity (ϕ), surface area (A_s), aspect ratio (R_a) and seed volume (V) of buckwheat grains.

Tabla 3. Coeficientes de correlación entre las dimensiones de las semillas (L, W y T), la esfericidad (ϕ), el área de superficie (A_s), la relación de aspecto (R_a) y el volumen de la semilla (V) de los granos de trigo sarraceno.

Species		W	T	Da	Dg	ϕ	As	Ra	V
Commercial buckwheat^a
	L	0.436**	0.327*	0.713**	0.676**	–0.503**	0.674**	–0.469**	0.672**
	W	1	0.899**	0.924**	0.937**	0.528**	0.939**	0.588**	0.938**
	T		1	0.877**	0.899**	0.633**	0.897**	0.592**	0.891**
	Da			1	0.998**	0.245^Ns	0.997**	0.268*	0.993**
	Dg				1	0.294*	0.999**	0.314*	0.995**
	ϕ					1	0.294*	0.975**	0.291*
	As						1	0.315*	0.999**
	Ra							1	0.315*
Güneş variety^a
	L	0.275*	0.257^Ns	0.758**	0.631**	–0.603**	0.629**	–0.531**	0.625**
	W	1	0.825**	0.813**	0.889**	0.569**	0.887**	0.666**	0.882**
	T		1	0.785**	0.869**	0.567**	0.872**	0.526**	0.875**
	Da			1	0.984**	0.061^Ns	0.983**	0.129^Ns	0.979**
	Dg				1	0.235^Ns	0.999**	0.293*	0.996**
	ϕ					1	0.236*	0.970**	0.237^Ns
	As						1	0.292*	0.999**
	Ra							1	0.289*

^Ns: not significant; ^a 98 degrees of freedom; * Significant level at 5%; ** Significant level at 1%.

^Ns: No es significativo; ^a 98 grados de libertad; * nivel de significancia a 5%; ** nivel de significancia a 1%.

Table 4. Colour parameters of buckwheat grains^a.

Tabla 4. Parámetros de color de los granos de trigo sarraceno¹.

Parameter	Commercial buckwheat	Güneş variety
L*	42.41 ± 0.95 a	36.08 ± 1.83 b
a*	11.45 ± 0.23 a	7.35 ± 0.12 b
b*	21.10 ± 0.44 a	14.66 ± 0.37 b
C	24.01 ± 0.49 a	16.40 ± 0.38 b
α	61.53 ± 0.13 b	63.40 ± 0.23 a

^aDifferent letter in the same line indicate significant differences (P < 0.05).

¹Las distintas letras en la misma línea indican diferencias significativas (P < 0,05).

Table 5. Chemical properties of buckwheat grains^a,b.

Tabla 5. Propiedades químicas de los granos de trigo sarraceno^1,2.

Property	Commercial buckwheat	Güneş variety
Total solids (g/100 g)	93.54 ± 0.26 a	90.54 ± 0.36 b
Ash (g/100 g)	2.56 ± 0.14 b	4.89 ± 0.86 a
Protein (g/100 g)	14.62 ± 0.41 a	13.75 ± 0.29 b
Antioxidant capacity (µmol TE/g)	1.41 ± 0.14 b	2.86 ± 0.16 a
Total phenolic content (mg GAE/100 g)	207.12 ± 2.67 b	329.83 ± 3.88 a
P (mg/kg)	3451.34 ± 62.39 Ns	3643.47 ± 101.85 Ns
K (mg/kg)	3900.00 ± 50.00 b	5458.33 ± 38.19 a
Mg (mg/kg)	1890.40 ± 12.06 b	2083.83 ± 21.03 a
Na (mg/kg)	741.67 ± 14.43 b	933.33 ± 14.43 a
Ca (mg/kg)	133.33 ± 14.43 b	916.67 ± 14.43 a
Fe (mg/kg)	44.01 ± 1.82 b	170.50 ± 4.20 a
Zn (mg/kg)	30.00 ± 1.36 a	24.29 ± 0.94 b
Mn (mg/kg)	13.88 ± 0.86 Ns	14.91 ± 0.41 Ns
Cu (mg/kg)	7.86 ± 0.46 Ns	8.26 ± 0.02 Ns
B (mg/kg)	0.49 ± 0.01 b	19.25 ± 0.25 a
Ni (mg/kg)	4.24 ± 0.47 a	2.85 ± 0.09 b
Cr (mg/kg)	0.66 ± 0.10 b	1.10 ± 0.07 a
Pb (mg/kg)	0.19 ± 0.01 b	0.24 ± 0.01 a
Cd (mg/kg)	–	–

^aDifferent letter in the same line indicates significant differences (P < 0.05).

^bBased on dry matter.

a and b letters indicate the statistical difference in rows.

Ns: Not significant

¹Las distintas letras en la misma línea indican diferencias significativas (P < 0,05).

²En base a la materia seca.

Las letras a y b indican diferencias significativas en las filas.

Ns: No es significativo