Quality evaluation and discrimination of flavouring process of garlic-flavoured vegetable oils

Figures & data

Table 1. Effects of flavouring processes on quality parameters.

Quality parameters
AV^c			∆AV^d	PV^e	∆PV^f	L^g	∆L	a	∆a	b	∆b
Canola	CMO^a	2.70 ± 0.04c	1.7	14.7 ± 0.5c	12.7	24.0 ± 0.1c	−12.7	2.80 ± 0.01a	−0.4	13.4 ± 0.1a	−0.9
	CAO^b	1.10 ± 0.02b	0.1	1.1 ± 0.1a	−1.0	25.2 ± 0.3ab	−1.0	3.8 ± 0.1c	0.6	16.4 ± 0.4b	2.0
	Control	1.00 ± 0.02a		2.0 ± 0.1b		26.1 ± 0.9b		3.2 ± 0.2b		14.4 ± 0.7a
Olive	OAM	1.8 ± 0.1c	1.1	9.4 ± 0.4a	−0.1	23.1 ± 0.2a	−1.0	−0.04 ± 0.01a	−0.6	14.6 ± 0.3a	−1.2
	OAO	0.4 ± 0.0a	−0.2	14.10 ± 0.01b	4.8	25.30 ± 0.04b	1.4	0.2 ± 0.0b	−0.5	14.50 ± 0.03a	−1.3
	Control	0.60 ± 0.01b		9.3 ± 0.1a		24 ± 1a		−0.6 ± 0.1c		15.9 ± 0.7b
Sunflower	SMO	1.30 ± 0.07b	1.3	16.7 ± 0.1c	15.0	28.4 ± 0.04a	−6.1	−0.40 ± 0.01a	−0.2	5.60 ± 0.04a	0.2
	SAO	0.1 ± 0.0a	0.05	3.0 ± 0.2b	1.3	30 ± 1a	−5.3	−0.9 ± 0.1b	0.3	6.9 ± 0.5b	1.4
	Control	0.1 ± 0.0a		1.7 ± 0.7a		34.5 ± 0.4b		−0.6 ± 0.0a		5.5 ± 0.1a

Values are mean ± standard deviation within each column followed by different letters that denote significant differences (P < 0.05), according to Tukey’s test.

^aMO: macerated oil

^bAO: aromatised oil

^cAV: acidity values expressed as g oleic acid g⁻¹

^d∆AV: delta acidity value difference

^ePV: peroxide values expressed in meq O₂ kg⁻¹

^f∆PV: delta peroxide value difference

^gColour: L: lightness; ʽaʼ: redness to greenness; ʽbʼ: yellowness to blueness

Table 2. OSC profiles of prepared flavoured oils.

	Macerated oils			Aromatised oils
OSCs^a (µg/g)	Canola	Olive	Sunflower	Canola	Olive	Sunflower
DAS	nd	46.5 ± 0.2^b	17 ± 4^a	nd	nd	18 ± 1^a
DADS	46 ± 1b	82 ± 2^c	25.8 ± 0.2^a	19.5 ± 0.1^a	31.8 ± 0.6^c	26.7 ± 0.1^bc
DATS	nd	nd	nd	90 ± 3^a	117 ± 3^b	117 ± 3^b
Allicin	4 ± 3a	nd	1.7 ± 0.2^a	nd	nd	nd
Ajoene	6 ± 2b	20 ± 3^c	0.90 ± 0.02a	nd	nd	nd
2-VD	131 ± 10c	35.8 ± 0.5^b	10.60 ± 0.02^a	nd	nd	nd
3-VD	nd	nd	10 ± 1	nd	nd	nd

Values are mean ± standard deviation within each column followed by different letters that denote significant differences (P < 0.05), according to Tukey’s test.

^aOSCs: DAS: diallyl sulphide; DADS: diallyl disulphide; DATS: diallyl trisulphide; 2-VD and 3-VD: isomers of vinyldithiins. nd: not detected (LOD/LOQ: DAS = 2.02/11.09; DADS = 0.01/4.51; Allicin = 1.38/4.44; E/Z ajoene = 0.01/0.62; 2-VD = 3.16/6.03).

Figure 1. Percentage composition of OSCs found in prepared flavoured oils.

Table 3. Physicochemical analysis of commercial flavoured garlic oils.

	PV^d	AV^e	Colour^f
			L	a	b
C1^a	2.8 ± 0.1b	0.40 ± 0.01^a,b,c	34.1 ± 0.2^b,c	−0.9 ± 0.1^a,b,c	5.9 ± 0.1^a
C2^a	2.7 ± 0.6b	0.2 ± 0.0^a,b	35.6 ± 0.2^c	−0.50 ± 0.03^b,c	7.1 ± 0.1^b
C3^b	0.7 ± 0.1a	1.40 ± 0.01^c	29.5 ± 0.1^a,b	0.80 ± 0.03^c	19.4 ± 0.2^d
C4^c	1.5 ± 0.3a	0.5 ± 0.0^b,c	30.2 ± 0.9^a,b,c	−1.4 ± 0.1^a	8.2 ± 0.4^c
C5^c	2.40 ± 0.03b	0.10 ± 0.02^a	26.6 ± 0.3^a	−1.10 ± 0.03^a,b	19.6 ± 0.4^d

Values are mean ± standard deviation within each column followed by different letters that denote significant differences (P < 0.05), according to Tukey’s test.

^aC1 and C2: commercial flavoured sunflower oils

^bC3: commercial aromatised canola oils

^cC4 and C5: commercial aromatised olive oils

^dPV: peroxide values expressed in meq O₂ kg⁻¹

^eAV: acidity values expressed as g oleic acid g⁻¹

^fColour: L: lightness; ʽaʼ: redness to greenness; ʽbʼ: yellowness to blueness.

Table 4. OSC profiles of commercial flavoured oils.

	OSCs (µg/g)
	DAS^b	DADS	DATS	Allicin	Ajoene	2-VD	3-VD
C1^a	4 ± 1b	10 ± 2a	29 ± 8a	nd	nd	nd	nd
C2	16.0 ± 0.2c	19 ± 5b	68 ± 3b	14.3 ± 0.8	30 ± 1b	154 ± 7b	traces
C3	29 ± 3d	14.2 ± 0.1a,b	28.9 ± 0.5a	nd	1.5 ± 0.6a	nd	nd
C4	nd	28 ± 5c	nd	nd	2.70 ± 0.01a	nd	nd
C5	0.37 ± 0.05a	12 ± 4a,b	66.6 ± 0.3b	nd	2.4 ± 0.2a	22 ± 2a	7 ± 2

Values are mean ± standard deviation within each column followed by different letters that denote significant differences (P < 0.05), according to Tukey’s test.

^aCommercial flavoured oils: C1 and C2: commercial flavoured sunflower oils; C3: commercial flavoured canola oil; C4 and C5: commercial flavoured olive oils

^bOSCs: DAS: diallyl sulphide; DADS: diallyl disulphide; DATS: diallyl trisulphide; 2-VD and 3-VD: isomers of vinyldithiins. nd: not detected (LOD/LOQ: DAS = 2.02/11.09; DADS = 0.01/4.51; Allicin = 1.38/4.44; E/Z ajoene = 0.01/0.62; 2-VD = 3.16/6.03).

Figure 2. Graph of the principal components (PCs) belonging to the flavoured oils analysed.