Effects of UV-C and single- and multiple-cycle high hydrostatic pressure treatments on flavor evolution of cow milk: Gas chromatography-mass spectrometry, electronic nose, and electronic tongue analyses

Figures & data

Table 1. Comparison of the content of volatile compounds (ng mL⁻¹) in milk treated with high hydrostatic pressure and UV-C radiation.

RT		CAS	Control	200 MPa	200 MPa	400 MPa	400 MPa	600 MPa	600 MPa	UV-C
(min)	Compounds	number	(untreated)	(1 × 5 min)	(2 × 2.5 min)	(1 × 5 min)	(2 × 2.5 min)	(1 × 5 min)	(2 × 2.5 min)	(5 min)
Acids
29.098	Hexanoic acid	142-62-1	70.92 ± 4.93^a	130.44 ± 9.08^c	147.24 ± 16.71^d	61.60 ± 6.29^a	92.82 ± 3.33^b	70.56 ± 5.74^a	72.76 ± 8.44^a	68.62 ± 5.60^a
33.549	Octanoic acid	124-07-2	123.07 ± 6.91^a	181.49 ± 12.38^c	179.52 ± 11.29^c	122.88 ± 1.31^a	156.28 ± 12.52^b	146.36 ± 19.59^ab	130.13 ± 17.57^a	125.54 ± 9.19^a
35.874	Nonanoic acid	112-05-0	2.21 ± 1.17^abc	3.15 ± 0.24^c	2.42 ± 0.37^bc	1.26 ± 0.25^a	1.59 ± 0.36^ab	2.75 ± 0.44^c	3.03 ± 0.71^c	9.25 ± 0.73^d
37.817	n-Decanoic acid	334-48-5	—	58.05 ± 4.20^de	50.47 ± 8.17^cd	38.41 ± 0.50^b	47.77 ± 6.42^bc	46.82 ± 4.96^bc	60.92 ± 6.78^e	54.10 ± 4.69^cde
Alcohols
10.344	1-Decanol, 2-hexyl-	2425-77-6	14.44 ± 1.27^b	21.55 ± 1.16^c	16.70 ± 1.72^b	23.00 ± 1.37^cd	14.46 ± 0.94^b	9.51 ± 0.94^a	24.42 ± 2.21^de	26.43 ± 1.99^e
13.937	1-Dodecanol	112-53-8	9.28 ± 0.86^b	10.05 ± 1.28^b	9.33 ± 1.90^b	6.52 ± 0.85^a	10.67 ± 1.50^b	8.42 ± 0.73^ab	8.76 ± 1.56^ab	22.91 ± 2.22^c
14.759	1-Pentanol	71-41-0	18.68 ± 2.41^bcd	14.87 ± 3.70^ab	11.21 ± 0.52^a	13.82 ± 3.22^ab	15.19 ± 4.14^abc	15.75 ± 1.13^abc	21.07 ± 3.34^d	20.18 ± 1.13^cd
16.905	1-Hexanol	111-27-3	—	—	—	—	—	—	—	13.30 ± 0.98^b
18.741	2-octanol	123-96-6	6.31 ± 0.54^c	3.98 ± 0.36^b	11.68 ± 2.08^d	2.01 ± 0.11^a	2.67 ± 0.32^ab	1.79 ± 0.13^a	2.52 ± 0.30^ab	3.96 ± 0.35^b
19.272	1-tetradecanol	112-72-1	—	—	—	—	—	—	—	16.46 ± 1.34^b
20.56	1-hexanol, 2-ethyl-	104-76-7	9.83 ± 0.70^bcd	10.64 ± 4.56^cd	10.23 ± 1.00^bcd	6.87 ± 0.71^ab	6.09 ± 1.18^a	5.41 ± 0.72^a	7.81 ± 2.02^abc	12.07 ± 1.17^d
22.26	1-octanol	111-87-5	11.20 ± 1.06^a	16.28 ± 0.53^c	15.47 ± 2.60^bc	11.16 ± 0.39^a	13.85 ± 0.89^abc	11.52 ± 0.24^a	13.10 ± 2.02^ab	32.89 ± 2.61^d
32.935	n-Tridecan-1-ol	112-70-9	8.67 ± 1.20^b	7.66 ± 2.21^b	8.60 ± 3.23^b	4.47 ± 0.34^a	4.70 ± 0.72^a	4.16 ± 0.13^a	6.79 ± 0.53^ab	5.97 ± 0.81^ab
Aldehydes
2.2	1-heptene	592-76-7	—	—	—	—	—	—	—	8.38 ± 3.16^b
2.268	Hexane, 2,2,5-trimethyl-	3522-94-9	—	7.94 ± 1.76^b	—	8.46 ± 1.35^b	—	—	12.58 ± 1.54^c	10.53 ± 3.77^bc
8.297	Hexanal	66-25-1	11.19 ± 1.12^b	5.95 ± 1.15^a	5.15 ± 0.48^a	6.96 ± 1.76^ab	2.78 ± 1.48^a	6.47 ± 1.89^a	15.77 ± 1.67^c	41.35 ± 6.26^d
11.601	Heptanal	111-71-7	—	—	6.38 ± 0.89^a	—	—	—	—	60.53 ± 9.61^b
17.879	Nonanal	124-19-6	13.81 ± 0.58^a	27.38 ± 6.82^a	17.22 ± 1.99^a	12.90 ± 1.29^a	14.09 ± 0.88^a	8.22 ± 0.15^a	9.09 ± 1.80^a	537.32 ± 59.58^b
20.681	Decanal	112-31-2	7.51 ± 5.62^b	4.30 ± 2.89^ab	2.65 ± 0.20^a	2.41 ± 0.22^a	3.20 ± 0.83^ab	3.49 ± 0.35^ab	3.67 ± 1.28^ab	16.06 ± 1.26^c
Aliphatic Hydrocarbons
2.336	Heptane, 3-methyl-	589-81-1	8.67 ± 1.60^ab	21.14 ± 2.77^c	6.55 ± 1.60^a	20.87 ± 1.07^c	21.63 ± 3.74^c	10.08 ± 2.22^ab	13.93 ± 3.79^b	12.46 ± 5.16^b
2.523	Octane	111-65-9	52.56 ± 2.64^b	137.99 ± 13.61^e	28.53 ± 2.94^a	104.68 ± 6.44^c	123.12 ± 8.89^d	57.65 ± 2.07^b	58.33 ± 5.21^b	38.49 ± 2.13^a
2.88	1-Octene	111-66-0	10.73 ± 0.97^ab	35.35 ± 9.06^c	6.91 ± 5.00^a	38.91 ± 2.02^c	44.37 ± 2.88^c	20.18 ± 5.28^b	16.64 ± 5.76^b	62.80 ± 6.06^d
3.488	Ethane, 1,1-diethoxy-	105-57-7	9.63 ± 0.50^a	13.75 ± 0.48^bc	12.45 ± 4.74^abc	14.87 ± 1.22^bc	16.22 ± 1.60^c	11.74 ± 1.19^ab	11.39 ± 2.22^ab	21.29 ± 1.51^d
4.702	Heptane, 2,2,4,6,6-pentamethyl-	55162-61-3	—	—	—	—	—	—	103.98 ± 10.33^b	111.85 ± 7.22^c
4.949	Nonane, 3-methyl-	5911-04-6	44.49 ± 17.48^a	108.64 ± 5.67^bc	130.25 ± 21.28^cd	134.46 ± 9.75^d	131.22 ± 11.30^cd	61.27 ± 13.97^a	118.28 ± 10.19^bcd	95.81 ± 6.38^b
5.847	Decane	124-18-5	54.39 ± 8.73^a	114.54 ± 7.08^c	92.87 ± 13.49^b	92.23 ± 6.04^b	91.40 ± 7.68^b	47.38 ± 1.42^a	87.28 ± 10.16^b	58.80 ± 4.49^a
7.108	1-decene	872-05-9	4.24 ± 0.37^a	13.35 ± 1.26^c	9.17 ± 0.69^b	10.16 ± 0.53^b	10.11 ± 1.04^b	4.48 ± 0.25^a	4.19 ± 0.79^a	38.08 ± 3.11^d
8.041	Cyclopentane, pentyl-	3741-00-2	4.66 ± 0.35^a	7.84 ± 0.94^a	5.54 ± 1.14^a	15.05 ± 1.29^b	7.97 ± 0.76^a	7.26 ± 1.33^a	19.57 ± 3.67^c	27.07 ± 3.71^d
8.654	Undecane, 5-methyl-	1632-70-8	4.82 ± 0.30^a	6.55 ± 0.53^ab	5.11 ± 1.52^a	10.84 ± 3.07^c	4.20 ± 0.15^a	8.95 ± 2.19^bc	17.24 ± 1.12^d	16.96 ± 1.52^d
8.757	Dodecane	112-40-3	7.57 ± 1.08^a	9.32 ± 1.15^a	6.52 ± 0.85^a	21.48 ± 8.74^c	5.63 ± 2.18^a	9.63 ± 3.63^a	12.21 ± 1.24^ab	18.34 ± 2.06^bc
9.441	Nonadecane	629-92-5	5.94 ± 2.30^a	5.08 ± 1.76^a	5.98 ± 1.35^a	15.04 ± 1.28^b	7.34 ± 4.37^a	6.86 ± 4.01^a	22.79 ± 4.41^c	15.50 ± 1.16^b
9.671	Undecane, 2,6-dimethyl-	17301-23-4	2.86 ± 0.09^a	4.57 ± 1.53^ab	4.31 ± 0.76^ab	6.50 ± 1.71^d	3.25 ± 0.12^a	3.58 ± 0.35^a	6.01 ± 1.07^bc	5.91 ± 0.53^bc
9.783	Decane, 2,5-dimethyl-	17312-50-4	4.04 ± 1.29^a	8.14 ± 2.40^d	6.35 ± 1.28^abc	5.30 ± 0.59^ab	6.34 ± 2.15^abc	6.08 ± 0.32^abc	7.06 ± 0.60^bc	5.87 ± 0.20^abc
10.94	Undecane, 3-methyl-	1002-43-3	25.14 ± 3.15^b	37.63 ± 2.97^c	25.82 ± 3.25^b	34.83 ± 1.29^c	22.54 ± 2.11^b	14.58 ± 0.49^a	38.16 ± 5.30^c	27.64 ± 1.88^b
11.849	D-Limonene	5989-27-5	6.64 ± 0.25^bc	6.60 ± 2.31^bc	12.22 ± 1.32^d	5.94 ± 0.54^abc	5.44 ± 0.69^ab	4.45 ± 0.83^a	6.62 ± 1.03^bc	7.75 ± 0.43^c
12.059	Dodecane	16661-24-8	13.72 ± 0.87^bc	19.17 ± 2.99^de	10.64 ± 2.73^a	16.25 ± 1.14^cd	10.91 ± 0.62^b	7.34 ± 0.69^a	20.99 ± 2.53^e	16.65 ± 1.33^cd
13.107	1-decyne	764-93-2	7.32 ± 0.39^ab	11.21 ± 0.89^bc	13.19 ± 5.60^c	7.03 ± 1.38^ab	9.54 ± 2.60^abc	5.13 ± 0.71^a	9.19 ± 0.92^abc	19.45 ± 1.88^d
17.147	Tridecane, 3-methyl-	6418-41-3	4.40 ± 0.29^c	5.84 ± 0.98^d	4.08 ± 0.22^bc	6.43 ± 0.90^d	3.01 ± 0.61^ab	2.51 ± 0.25^a	8.07 ± 1.28^e	5.71 ± 0.25^d
Aromatic Hydrocarbons
6.931	Toluene	108-88-3	307.01 ± 31.09^c	271.84 ± 16.78^bc	452.63 ± 39.17^e	165.65 ± 8.50^a	254.79 ± 21.22^b	159.68 ± 19.60^a	353.65 ± 39.31^d	198.58 ± 16.20^a
9.543	Ethylbenzene	100-41-4	3.13 ± 0.58^a	4.10 ± 0.44^a	5.72 ± 1.06^b	7.63 ± 0.29^c	11.24 ± 1.27^d	3.22 ± 1.14^a	2.76 ± 0.40^a	7.69 ± 0.45^c
33.451	Phenol, 3-methyl-	108-39-4	—	—	—	—	—	—	—	4.07 ± 0.25^b
37.672	Phenol, 2,4-bis(1,1-dimethylethyl)-	96-76-4	62.81 ± 5.02^d	17.00 ± 4.88^ab	14.09 ± 3.08^a	20.26 ± 3.88^ab	17.86 ± 3.82^ab	27.82 ± 0.66^c	21.17 ± 2.69^b	31.96 ± 2.46^c
Esters
5.445	Butanoic acid, methyl ester	623-42-7	15.51 ± 3.77^ab	23.12 ± 6.01^c	10.14 ± 1.85^a	13.52 ± 2.87^a	11.26 ± 0.75^a	11.15 ± 4.58^a	20.55 ± 2.99^bc	14.42 ± 0.99^ab
11.748	Hexanoic acid, methyl ester	106-70-7	8.87 ± 0.53^e	7.75 ± 1.50^de	6.13 ± 1.36^bcd	4.62 ± 0.74^abc	4.34 ± 1.33^ab	4.23 ± 0.35^a	4.75 ± 0.46^abc	6.34 ± 0.90^cd
13.463	Hexanoic acid, ethyl ester	123-66-0	5.95 ± 0.29^ab	9.04 ± 2.66^c	6.59 ± 0.79^abc	5.63 ± 0.45^ab	5.75 ± 1.59^ab	4.46 ± 1.27^a	7.71 ± 1.76^bc	28.29 ± 2.21^d
19.055	Octanoic acid, ethyl ester	106-32-1	5.46 ± 1.00^a	9.39 ± 1.25^cde	8.31 ± 1.74^bc	7.08 ± 1.16^ab	11.53 ± 0.99^e	11.03 ± 0.71^de	9.60 ± 1.93^cde	8.92 ± 0.13^bcd
Ethers
1.869	Ethyl ether	60-29-7	75.99 ± 6.84^b	83.59 ± 5.52^b	66.24 ± 11.73^ab	66.40 ± 10.26^ab	72.96 ± 8.92^ab	68.73 ± 5.86^ab	56.16 ± 7.85^a	69.50 ± 15.38^ab
3.371	Ethyl acetate	141-78-6	3.16 ± 0.59^a	6.82 ± 0.92^b	7.17 ± 2.96^b	9.37 ± 1.13^bc	10.40 ± 0.66^c	7.98 ± 1.81^bc	6.73 ± 2.01^b	16.58 ± 1.50^d
Ketones
2.64	Acetone	67-64-1	24.31 ± 7.62^a	32.03 ± 1.43^ab	38.80 ± 7.69^b	27.31 ± 5.65^a	27.20 ± 4.63^a	29.89 ± 3.04^ab	37.99 ± 3.01^b	27.23 ± 1.48^a
3.58	2-Butanone	78-93-3	10.77 ± 1.55^ab	13.88 ± 0.40^b	14.67 ± 4.89^b	13.11 ± 1.33^b	14.67 ± 1.35^b	12.07 ± 1.31^b	8.00 ± 0.52^a	27.62 ± 2.43^c
16.606	Cyclopentanone, 2-methyl-	1120-72-5	—	—	—	—	—	—	—	5.46 ± 0.38^b
35.589	2H-Pyran-2-one, Tetrahydro-6-pentyl-	542-28-9	5.23 ± 0.43^abc	7.28 ± 0.88^de	6.74 ± 1.95^cde	4.44 ± 0.21^ab	5.86 ± 0.56^bcd	6.40 ± 0.95^cd	8.19 ± 0.68^e	3.99 ± 0.14^a
Sulfur compounds
29.763	Dimethyl sulfone	67-71-0	0.81 ± 0.08^abc	0.83 ± 0.07^abc	0.92 ± 0.06^c	0.71 ± 0.08^a	0.76 ± 0.05^ab	0.71 ± 0.07^a	0.75 ± 0.05^ab	0.88 ± 0.09^bc

RT: retention time (min).

Values were expressed as average ± SD (n = 3).

Figure 1. Principal component analysis A and linear discriminant analysis B of volatile compounds of (1) untreated; (2) UV-C-treated; and (3) high hydrostatic pressure treated (200 MPa [2 × 2.5 min]; 4: 400 MPa [2 × 2.5 min]; 5: 600 MPa [2 × 2.5 min]; 6: 200 MPa [1 × 5 min]; 7: 400 MPa [1 × 5 min]; 8: 600 MPa [1 × 5min]) milk samples by e-nose.

Figure 2. Principal component analysis A and linear discriminant analysis B of (1) untreated; (2) UV-C-treated; and (3) high hydrostatic pressure treated (200 MPa [2 × 2.5 min]; 4: 400 MPa [2 × 2.5 min]; 5: 600 MPa [2 × 2.5 min]; 6: 200 MPa [1 × 5 min]; 7: 400 MPa [1 × 5 min]; 8: 600 MPa [1 × 5 min]) milk samples by e-tongue.