Effect of roasting on physicochemical and functional properties of flaxseed flour

Figures & data

Table 1. Physical properties of flaxseed

Parameters	Flaxseed
Moisture content
Moisture content (%w.b.)	7.66 ± .52
Moisture content (%d.b.)	8.29 ± .62
Color values
L*	46.63 ± .25
a*	8.21 ± .37
b*	8.96 ± .01
Geometrical properties
Length X(mm)	5.43 ± .25
Width Y(mm)	3.39 ± .15
Thickness Z (mm)	1.69 ± .24
Geometric mean diameter D g (mm)	2.19 ± .03
Arithmetric mean diameter D a (mm)	3.51 ± .17
Sphericity ϕ (%)	40.34 ± 1.38
Surface area S (mm^2)	15.08 ± .49
Gravimetric properties
Bulk density, ρ b (g/cm^3)	.66 ± .08
True density, ρ s (g/cm^3)	1.34 ± .09
Porosity, ε (%)	51.56 ± 4.72
Aspect ratio, R a (%)	62.58 ± 3.25
Thousand kernel weight (g)	7.14 ± .26
Friction properties
Angle of repose (°)	19.40 ± 1.27
Static coefficient of friction
Glass	.32 ± .01
Stainless steel	.36 ± .02
Plywood perpendicular	.33 ± .01
Plywood parallel	.33 ± .01

Results are expressed as mean ± SD of triplicate observations.

Figure 1. Dimensional representation of flaxseed

Table 2. Physical and functional properties of wheat and flaxseed flour

Parameters	WF	URFF	RFF
Bulk density (g/cm^3)	.49 ± .01^a	.47 ± .01^a	.48 ± .01^a
Tap density (g/cm^3)	.60 ± .03^b	.81 ± .01^a	.77 ± .06^a
True density (g/cm^3)	1.40 ± .13^b	1.77 ± .19^a	1.58 ± .13^ab
Porosity (%)	64.44 ± 3.72^b	73.01 ± 2.80^a	69.09 ± 2.99^ab
Angle of repose (°)	33.60 ± 1.25^c	39.71 ± .52^a	36.56 ± .26^b
WAI (g/g)	4.89 ± .18^b	5.96 ± .05^a	5.33 ± .57^ab
WSI (%)	4.24 ± .26^c	6.61 ± .20^b	10.83 ± .74^a
Functional properties
WAC (g/g)	.63 ± .04^b	1.47 ± .17^a	1.61 ± .27^a
OAC (g/g)	1.14 ± .03^a	1.08 ± .19^a	.96 ± .20^a
Foaming capacity (%)	30.40 ± .76^a	9.23 ± .23^b	7.82 ± .02^c
Foaming stability (%)	56.05 ± 5.56^a	54.43 ± 1.07^ab	48.60 ± .51^b
Sedimentation value (ml)	23.56 ± 1.25^a	24.93 ± .58^a	23.60 ± .50^a

Mean  ± SD with different superscripts in a row differ significantly (p < .05) (n = 3). WF = wheat flour.

URFF = unroasted flaxseed flour; RFF = roasted flaxseed flour. WAI: water absorption index.

WSI: water solubility index; WAC: water absorption capacity; OAC: oil absorption capacity.

Table 3. Physicochemical properties and color of wheat and flaxseed flour

Parameters	WF	URFF	RFF
Moisture (%)	13.55 ± .25^a	4.71 ± .23^b	4.13 ± .58^b
Protein (%)	11.46 ± 1.25^b	23.78 ± 2.19^a	22.83 ± 2.40^a
Crude Fat (%)	1.30 ± .43^b	32.27 ± .39^a	31.05 ± 1.05^a
Ash (%)	.78 ± .05^b	3.16 ± .05^a	3.29 ± .085^a
Crude fiber (%)	.57 ± .19^b	9.34 ± .22^a	9.63 ± .29^a
Carbohydrate (%)	71.47^a	26.72^b	29.06^b
Energy value (Cal/100 g)	346.84^b	492.51^a	487.04^a
Color
L*	92.65 ± .28^a	45.40 ± .31^b	34.43 ± .11^c
a*	2.13 ± .07^c	7.61 ± .15^a	6.95 ± .05^b
b*	9.89 ± .15^b	10.72 ± .07^a	9.27 ± .06^c
∆E	–	47.57 ± .30^b	58.42 ± .10^a
Whiteness index	87.48^a	43.84^b	33.41^c

Mean ± SD with different superscripts in a row differ significantly (p < .05) (n = 3). WF = wheat flour.

URFF = unroasted flaxseed flour; RFF = roasted flaxseed flour.

Table 4. Least gelation concentration of wheat flour and different flaxseed samples

Flour conc. (%)	WF	URFF	RFF
2	No gel	No gel	No gel
4	No gel	No gel	No gel
6	No gel	No gel	Gel
8	No gel	Gel	Gel
10	No gel	Firm gel	Firm gel
12	Gel	Firm gel	Firm gel
14	Gel	Very firm gel	Firm gel
16	Firm gel	Very firm gel	Very firm gel
18	Firm gel	Very firm gel	Very firm gel
20	Very firm gel	Very firm gel	Very firm gel

WF = wheat flour; URFF = unroasted flaxseed flour; RFF = roasted flaxseed flour.