Quality profile determination of palm olein: potential markers for the detection of recycled cooking oils

Figures & data

Table 1. Determination of the smoke points of commercial cooking oils

Type of cooking oil	Sample	Smoke point (°C)
Pure Palm Olein (PPO)	PPO1	221.00 ± 1.41^i
	PPO2	181.00 ± 1.41^a
	PPO3	189.50 ± 0.71^cde
	PPO4	200.00 ± 1.41^fg
	PPO5	226.50 ± 0.71^j
	PPO6	209.50 ± 0.71^h
	PPO7	197.50 ± 0.71^f
	PPO8	209.50 ± 0.71^h
	PPO9	222.50 ± 0.71^ij
Blended Palm Olein (BPO)	BPO1	225.00 ± 1.41^ij
	BPO2	203.50 ± 0.71^g
	BPO3	185.50 ± 0.71^bc
Packet Oil (PO)	PO1	184.70 ± 1.84^ab
	PO2	208.00 ± 1.41^h
	PO3	189.50 ± 0.71^cde
	PO4	192.00 ± 1.41^e
	PO5	189.50 ± 0.71^cde
	PO6	191.35 ± 0.92^de
	PO7	196.90 ± 0.14^f
	PO8	187.55 ± 0.64^bcd
	PO9	202.50 ± 0.71^g
	PO10	187.70 ± 0.42^bcd
	PO11	192.50 ± 0.71^e

*Data are expressed as the mean ± standard deviation (n = 4). Mean values with different superscripts in the same column are significantly different at p < 0.05.

Table 2. Determination of the polar fraction content and composition of commercial cooking oils

Type of cooking oil	Sample	Polar fraction content (%, g 100 g^−1)	Polar fraction composition (%, g 100 g^−1)
			TAG Oligomers	TAG Dimers	Oxidized TAG Monomers	Diacylglycerols	Free Fatty Acids
Pure Palm Olein (PPO)	PPO1	7.04 ± 0.13^abc	N.D.	0.31 ± 0.04^bcdef	0.97 ± 0.11^ab	5.58 ± 0.01^ab	0.18 ± 0.01^ab
	PPO2	8.47 ± 0.06^cd	N.D.	0.39 ± 0.01^ef	1.10 ± 0.24^abc	6.40 ± 0.08^abc	0.58 ± 0.10^c
	PPO3	7.52 ± 0.00^abc	N.D.	0.36 ± 0.07^def	0.80 ± 0.09^ab	6.01 ± 0.05^ab	0.36 ± 0.21^abc
	PPO4	6.96 ± 0.91^ab	N.D.	0.28 ± 0.04^bcdef	0.89 ± 0.08^ab	5.56 ± 0.75^ab	0.22 ± 0.03^ab
	PPO5	7.87 ± 0.30^abc	N.D.	0.24 ± 0.01^abcde	1.18 ± 0.38^abc	6.22 ± 0.21^ab	0.22 ± 0.12^ab
	PPO6	7.26 ± 0.33^abc	N.D.	0.26 ± 0.02^bcdef	0.94 ± 0.26^ab	5.80 ± 0.12^ab	0.25 ± 0.03^ab
	PPO7	8.19 ± 0.40^abcd	N.D.	0.29 ± 0.03^bcdef	0.84 ± 0.06^ab	6.73 ± 0.30^abc	0.34 ± 0.07^abc
	PPO8	7.22 ± 0.17^abc	N.D.	0.42 ± 0.01^f	1.00 ± 0.11^ab	5.56 ± 0.17^ab	0.24 ± 0.11^ab
	PPO9	8.25 ± 0.01^abcd	N.D.	0.38 ± 0.01^ef	1.73 ± 0.16^cd	5.99 ± 0.19^ab	0.14 ± 0.00^ab
Blended Palm Olein (BPO)	BPO1	7.31 ± 0.01^abc	N.D.	0.24 ± 0.02^abcde	0.93 ± 0.17^ab	5.98 ± 0.08^ab	0.16 ± 0.08^ab
	BPO2	7.40 ± 0.26^abc	N.D.	0.32 ± 0.03^bcdef	1.30 ± 0.21^abcd	5.47 ± 0.42^a	0.30 ± 0.08^abc
	BPO3	9.67 ± 0.38^d	N.D.	0.32 ± 0.04^bcdef	1.41 ± 0.32^bcd	7.52 ± 0.06^c	0.42 ± 0.03^bc
Packet Oil (PO)	PO1	7.67 ± 0.13^abc	N.D.	0.27 ± 0.06^bcdef	0.93 ± 0.15^ab	6.21 ± 0.25^ab	0.25 ± 0.03^ab
	PO2	6.84 ± 0.02^a	N.D.	0.17 ± 0.01^abc	0.66 ± 0.04^a	5.80 ± 0.05^ab	0.20 ± 0.03^ab
	PO3	7.91 ± 0.01^abc	N.D.	0.36 ± 0.00^def	1.29 ± 0.01^abcd	5.99 ± 0.02^ab	0.28 ± 0.01^ab
	PO4	7.69 ± 0.11^abc	N.D.	0.29 ± 0.10^bcdef	1.12 ± 0.01^abc	6.10 ± 0.03^ab	0.19 ± 0.01^ab
	PO5	8.24 ± 0.02^abcd	N.D.	0.16 ± 0.04^ab	1.35 ± 0.02^abcd	6.38 ± 0.02^abc	0.34 ± 0.07^abc
	PO6	7.37 ± 0.11^abc	N.D.	0.19 ± 0.01^abcd	0.79 ± 0.14^ab	6.17 ± 0.09^ab	0.21 ± 0.05^ab
	PO7	7.61 ± 0.38^abc	N.D.	0.34 ± 0.06^cdef	1.05 ± 0.28^abc	5.89 ± 0.19^ab	0.32 ± 0.04^abc
	PO8	8.35 ± 1.00^bcd	N.D.	0.08 ± 0.01^a	1.93 ± 0.13^d	6.10 ± 0.90^ab	0.24 ± 0.03^ab
	PO9	7.57 ± 0.59^abc	N.D.	0.16 ± 0.05^ab	1.08 ± 0.11^abc	6.03 ± 0.44^ab	0.29 ± 0.00^abc
	PO10	8.18 ± 0.21^abcd	N.D.	0.24 ± 0.01^abcde	1.15 ± 0.03^abc	6.40 ± 0.14^abc	0.39 ± 0.05^abc
	PO11	7.41 ± 0.37^abc	N.D.	0.76 ± 0.10^g	0.87 ± 0.04^ab	5.66 ± 0.28^ab	0.12 ± 0.05^a

N.D.: not detected

*Data are expressed as the mean ± standard deviation (n = 4). Mean values with different superscripts in the same column are significantly different at p < 0.05.

Table 3. Quantitative determination of epoxyFAMEs, ketoFAMEs and hydroxyFAMEs (g/100 g) in commercial cooking oils

Type of cooking oil	Sample	EpoxyFAMEs	KetoFAMEs	HydroxyFAMEs
Pure Palm Olein (PPO)	PPO1	N.D.	N.D.	N.D.
	PPO2	N.D.	N.D.	N.D.
	PPO3	N.D.	N.D.	N.D.
	PPO4	N.D.	N.D.	N.D.
	PPO5	N.D.	N.D.	N.D.
	PPO6	N.D.	N.D.	N.D.
	PPO7	N.D.	N.D.	N.D.
	PPO8	N.D.	N.D.	N.D.
	PPO9	N.D.	N.D.	N.D.
Blended Palm Olein (BPO)	BPO1	N.D.	N.D.	N.D.
	BPO2	N.D.	N.D.	N.D.
	BPO3	N.D.	N.D.	N.D.
Packet Oil (PO)	PO1	N.D.	N.D.	N.D.
	PO2	N.D.	N.D.	N.D.
	PO3	N.D.	N.D.	N.D.
	PO4	N.D.	N.D.	N.D.
	PO5	N.D.	N.D.	N.D.
	PO6	N.D.	N.D.	N.D.
	PO7	N.D.	N.D.	N.D.
	PO8	N.D.	N.D.	N.D.
	PO9	N.D.	N.D.	N.D.
	PO10	N.D.	N.D.	N.D.
	PO11	N.D.	N.D.	N.D.

N.D.: not detected

*Data are expressed as the mean ± standard deviation (n = 4). Mean values with different superscripts in the same column are significantly different at p < 0.05.

Table 4. Determination of the fatty acid composition of commercial cooking oils

		Fatty acid composition (relative percentages)
Type of cooking oil	Sample	C12:0	C14:0	C16:0	C18:0	C18:1	C18:2	C18:3	C18:2/C16:0	C8 (ppm)
Pure Palm Olein (PPO)	PPO1	0.29 ± 0.00^efgh	1.57 ± 0.32^a	38.28 ± 0.07^defg	4.18 ± 0.02^ijk	44.70 ± 0.21^bc	10.94 ± 0.01^fghij	0.00 ± 0.00^a	0.29 ± 0.00^ij	0.15 ± 0.22^a
	PPO2	0.52 ± 0.00^i	1.80 ± 0.01^a	36.26 ± 0.02^bc	3.99 ± 0.01^cdefghi	45.04 ± 0.02^bc	12.33 ± 0.00^k	0.00 ± 0.00^a	0.34 ± 0.00^n	0.88 ± 0.01^c
	PPO3	0.25 ± 0.00^bcdefg	1.82 ± 0.16^a	38.88 ± 0.05^g	4.22 ± 0.02^jk	44.12 ± 0.06^b	10.68 ± 0.03^defgh	0.00 ± 0.00^a	0.27 ± 0.00^h	0.00 ± 0.00^a
	PPO4	0.32 ± 0.00^fgh	1.79 ± 0.04^a	36.55 ± 0.01^bcde	3.86 ± 0.01^bcd	45.90 ± 0.04^bc	11.54 ± 0.00^j	0.00 ± 0.00^a	0.32 ± 0.00^m	0.07 ± 0.03^a
	PPO5	0.36 ± 0.00^gh	1.47 ± 0.01^a	36.42 ± 0.01^bcd	3.73 ± 0.01^b	46.90 ± 0.00^c	11.07 ± 0.01^ghij	0.00 ± 0.00^a	0.30 ± 0.00^k	0.54 ± 0.12^b
	PPO6	0.39 ± 0.00^h	1.86 ± 0.03^a	37.97 ± 0.00^cdefg	3.96 ± 0.00^cdefgh	45.81 ± 0.02^bc	9.97 ± 0.04^bc	0.00 ± 0.00^a	0.26 ± 0.00^de	0.20 ± 0.02^a
	PPO7	0.12 ± 0.00^a	1.81 ± 0.07^a	38.50 ± 0.01^efg	3.86 ± 0.00^bc	44.54 ± 0.05^b	11.17 ± 0.01^hij	0.00 ± 0.00^a	0.29 ± 0.00^j	0.00 ± 0.00^a
	PPO8	0.32 ± 0.00^fgh	1.80 ± 0.06^a	39.02 ± 0.00^g	4.26 ± 0.01^k	43.96 ± 0.05^b	10.61 ± 0.01^cdefgh	0.00 ± 0.00^a	0.27 ± 0.00^gh	0.17 ± 0.02^a
	PPO9	0.29 ± 0.00^defgh	1.49 ± 0.00^a	39.17 ± 0.00^g	4.09 ± 0.00^fghijk	44.57 ± 0.01^b	10.37 ± 0.00^cdef	0.00 ± 0.00^a	0.26 ± 0.00^ef	0.00 ± 0.00^a
Blended Palm Olein (BPO)	BPO1	0.25 ± 0.00^bcdefg	1.50 ± 0.02^a	36.86 ± 0.00^bcdef	4.09 ± 0.01^fghijk	45.87 ± 0.01^bc	11.41 ± 0.00^ij	0.00 ± 0.00^a	0.31 ± 0.00^l	0.00 ± 0.00^a
	BPO2	0.31 ± 0.00^fgh	2.08 ± 0.17^a	37.98 ± 0.01^cdefg	4.05 ± 0.01^cdefghij	44.68 ± 0.11^bc	10.80 ± 0.04^efghi	0.00 ± 0.00^a	0.28 ± 0.00^i	2.13 ± 0.25^d
	BPO3	0.32 ± 0.00^fgh	1.94 ± 0.10^a	35.63 ± 0.00^b	3.98 ± 0.01^cdefgh	45.56 ± 0.07^bc	12.53 ± 0.02^k	0.00 ± 0.00^a	0.35 ± 0.00°	0.12 ± 0.05^a
Packet Oil (PO)	PO1	0.13 ± 0.00^ab	1.97 ± 0.01^a	39.70 ± 0.01^g	3.91 ± 0.00^bcdef	44.13 ± 0.02^b	10.16 ± 0.00^bcde	0.00 ± 0.00^a	0.26 ± 0.00^bc	0.00 ± 0.00^a
	PO2	0.34 ± 0.00^gh	2.11 ± 0.04^a	37.93 ± 0.00^cdefg	3.89 ± 0.00^bcde	45.30 ± 0.03^bc	10.39 ± 0.01^cdef	0.00 ± 0.00^a	0.27 ± 0.00^h	0.00 ± 0.00^a
	PO3	0.19 ± 0.00^abcde	2.22 ± 0.06^a	39.10 ± 0.04^g	4.12 ± 0.01^hijk	44.30 ± 0.00^b	10.07 ± 0.01^bcd	0.00 ± 0.00^a	0.26 ± 0.00^bc	0.00 ± 0.00^a
	PO4	0.14 ± 0.00^abc	2.79 ± 0.18^a	39.34 ± 0.06^g	3.92 ± 0.00^bcdefg	43.63 ± 0.11^b	10.18 ± 0.01^bcde	0.00 ± 0.00^a	0.26 ± 0.00^cd	0.00 ± 0.00^a
	PO5	0.26 ± 0.00^defg	2.34 ± 0.09^a	38.52 ± 0.02^efg	4.01 ± 0.01^cdefghi	45.21 ± 0.06^bc	9.63 ± 0.00^b	0.00 ± 0.00^a	0.25 ± 0.00^a	0.00 ± 0.00^a
	PO6	0.22 ± 0.00^abcdef	1.70 ± 0.04^a	38.75 ± 0.03^fg	4.07 ± 0.00^efghijk	44.82 ± 0.02^bc	10.42 ± 0.00^cdefg	0.00 ± 0.00^a	0.27 ± 0.00^fg	0.00 ± 0.00^a
	PO7	0.17 ± 0.00^abcd	2.50 ± 0.03^a	38.95 ± 0.00^g	4.11 ± 0.00^ghijk	44.19 ± 0.02^b	10.07 ± 0.00^bcd	0.00 ± 0.00^a	0.26 ± 0.00^cd	0.00 ± 0.00^a
	PO8	0.10 ± 0.14^a	19.15 ± 6.19 ^b	32.82 ± 2.35^a	3.23 ± 0.22^a	36.40 ± 2.71^a	8.31 ± 0.77^a	0.00 ± 0.00^a	0.25 ± 0.01^ab	0.00 ± 0.00^a
	PO9	0.28 ± 0.00^defgh	2.23 ± 0.09^a	38.84 ± 0.02^fg	4.05 ± 0.00^defghij	44.31 ± 0.05^b	10.25 ± 0.01^bcde	0.00 ± 0.00^a	0.26 ± 0.00^e	0.00 ± 0.02^a
	PO10	0.26 ± 0.00^cdefg	1.96 ± 0.07^a	37.82 ± 0.01^cdefg	3.93 ± 0.00^bcdefg	45.54 ± 0.05^bc	10.46 ± 0.02^cdefg	0.00 ± 0.00^a	0.28 ± 0.00^h	0.00 ± 0.01^a
	PO11	0.28 ± 0.00^defgh	2.00 ± 0.02^a	38.99 ± 0.03^g	4.03 ± 0.00^cdefghi	44.37 ± 0.04^b	10.30 ± 0.02^cdef	0.00 ± 0.00^a	0.26 ± 0.00^ef	0.00 ± 0.00^a

*Data are expressed as the mean ± standard deviation (n = 4). Mean values with different superscripts in the same column are significantly different at p < 0.05.

Figure 1. Principal component (a) score plot and (b) biplot based on quality of commercial cooking oil samples (PPO = pure palm olein; BPO = blended palm olein; PO = packet oil)

* TPC: total polar compounds; TAG: triacylglycerol; OXTAG: oxidized triacylglycerol monomers; DAG: diacylglycerols; FFA: free fatty acids