. 2020 Dec 16;11:614208. doi: 10.3389/fmicb.2020.614208

TABLE 2.

Concentrations of volatile compounds in Kazak cheeses sampled at 40 days (μg/kg).

Compound	Calculated RI	IA	Control	KmC	PkC	PfC
Alcohols
Ethanol	932	MS	434.46 ± 9.6^b	81.29 ± 2.5^d	898.64 ± 17.8^a	271.76 ± 7.5^c
Isobutanol	1092	MS	24.36 ± 3.5^b	21.73 ± 1.6^b	50.92 ± 1.6^a	9.38 ± 0.6^c
Isoamylol	1209	MS	290.25 ± 7.3^b	7.90 ± 0.7^d	649.08 ± 12.4^a	52.20 ± 1.2^c
Pentanol	1250	MS, RI	4.37 ± 0.3^b	92.30 ± 1.9^a	5.97 ± 0.8^b	4.69 ± 0.2^b
4-Methyl-hexan-2-ol	1327	MS	1.16 ± 0.3^b	195.04 ± 6.3^a	4.97 ± 0.3^b	2.46 ± 0.1^b
1-Hexanol	1355	MS	5.19 ± 0.4^c	14.40 ± 1.7^b	20.94 ± 0.2^a	5.97 ± 0.5^c
3-Octanol	1393	MS, RI	1.87 ± 0.1^c	40.22 ± 3.2^a	5.75 ± 0.4^b	0.90 ± 0.1^c
2-Ethylhexanol	1491	MS, RI	1.27 ± 0.2^b	1963.82 ± 35.7^a	2.12 ± 0.1^b	nd
2,3-Butanediol	1543	MS, RI	322.98 ± 1.8^c	4071.46 ± 43.8^a	416.49 ± 8.6^b	117.34 ± 2.8^d
1-Octanol	1557	MS, RI	3.62 ± 0.6^c	7.62 ± 0.3^a	6.48 ± 0.9^b	3.55 ± 0.3^c
Isobutoxypropanol	1582	MS	44.61 ± 1.3^b	695.07 ± 38.2^a	51.64 ± 1.5^b	18.14 ± 0.9^b
4-Methyl-2-pentenal	1604	MS	1.98 ± 0.1^b	27.80 ± 1.7^a	2.57 ± 0.2^b	nd
1-Non-anol	1660	MS, RI	2.50 ± 0.2^bc	11.57 ± 2.5^a	4.13 ± 0.4^b	1.52 ± 0.1^c
1,3-Butanediol	1576	MS, RI	nd	1186.32 ± 32.6	nd	nd
Methionol	1719	MS, RI	2.58 ± 0.1^b	1196.36 ± 28.5^a	3.96 ± 0.2^b	1.33 ± 0.3^b
α-Cumyl alcohol	1773	MS, RI	0.41 ± 0.1^b	6.49 ± 0.7^a	nd	0.66 ± 0.1^b
Phenylethanol	1906	MS, RI	128.63 ± 3.6^b	222.00 ± 4.3^a	1.23 ± 0.1^d	9.71 ± 0.4^c
2-Methylheptan-2-ol	1053	MS	Nd	8.75 ± 0.5	10.27 ± 0.9	nd
Aldehydes
Hexanal	1083	MS, RI	0.64 ± 0.1^c	36.69 ± 2.7^a	30.32 ± 2.4^b	2.13 ± 0.3^c
2-Heptenal	1322	MS, RI	0.86 ± 0.1^c	5.08 ± 0.4^a	2.07 ± 0.3^b	0.99 ± 0.1^c
Non-anal	1391	MS, RI	5.94 ± 0.8^c	58.71 ± 0.6^a	15.24 ± 2.6^b	13.93 ± 0.3^b
Decanal	1498	MS, RI	nd	1.27 ± 0.2^b	2.01 ± 0.2^a	1.52 ± 0.1^b
3-Butanolal	2423	MS	0.34 ± 0.1^c	1.41 ± 0.1^a	1.06 ± 0.1^b	0.90 ± 0.1^b
Acids
Acetic acid	1449	MS, RI	465.28 ± 26.3^c	187.14 ± 17.5^d	815.79 ± 45.2^a	728.22 ± 33.6^b
Isobutyric acid	1570	MS, RI	98.11 ± 10.4^c	56.73 ± 2.1^d	195.13 ± 20.7^a	167.41 ± 14.2^b
Butanoic acid	1625	MS, RI	64.82 ± 9.4^d	383.31 ± 21.8^a	158.28 ± 17.3^b	111.51 ± 7.7^c
2-Methylcaproic acid	1757	MS, RI	55.18 ± 6.9^c	8.47 ± 1.5^d	159.84 ± 14.8^b	285.36 ± 26.3^a
Pentanoic acid	1733	MS, RI	0.90 ± 0.1^c	6.49 ± 0.7^a	1.84 ± 0.3^b	1.61 ± 0.4^bc
2-Methylvalerate	1764	MS	1.98 ± 0.2^b	nd	1.73 ± 0.1^b	5.87 ± 0.2^a
Hexanoic acid	1846	MS, RI	69.60 ± 6.3^c	nd	142.98 ± 7.3^a	120.94 ± 5.7^b
Heptanoic acid	1950	MS, RI	1.42 ± 0.2^b	387.68 ± 37.4^a	0.56 ± 0.1^b	0.33 ± 0.1^b
Non-anoic acid	2171	MS, RI	0.41 ± 0.1^b	1.13 ± 0.1^b	1.28 ± 0.2^b	51.59 ± 2.5^a
Octanoic acid	2060	MS, RI	25.07 ± 1.5^a	16.09 ± 2.8^b	0.17 ± 0.1^d	8.15 ± 1.1^c
Benzoic acid	2412	MS, RI	6.28 ± 1.8^b	13.97 ± 1.5^a	16.41 ± 2.1^a	nd
Esters
Ethyl acetate	888	MS, RI	620.10 ± 48.4^a	493.96 ± 42.9^b	690.90 ± 37.4^a	267.28 ± 26.4^c
Isobutyl acetate	1012	MS, RI	4.97 ± 1.1^c	22.30 ± 1.6^b	4.13 ± 1.3^c	30.06 ± 2.9^a
Ethyl butanoate	1035	MS, RI	12.59 ± 1.2^c	178.53 ± 5.1^a	30.65 ± 1.8^b	nd
Isoamyl acetate	1122	MS, RI	571.08 ± 16.4^b	36.69 ± 1.7^c	573.21 ± 34.1^b	1931.13 ± 41.7^a
Ethyl hexanoate	1233	MS, RI	35.83 ± 2.9^b	23.57 ± 2.8^c	73.97 ± 6.3^a	15.02 ± 2.8^d
Hexyl acetate	1272	MS	2.32 ± 0.2^c	10.02 ± 1.4^a	nd	7.63 ± 1.2^b
Ethyl tert-butylacetate	1334	MS	0.97 ± 0.1^b	2.54 ± 0.6^a	2.46 ± 0.2^a	1.09 ± 0.1^b
Ethyl propanoate	1365	MS	0.26 ± 0.1^b	nd	3.07 ± 1.1^a	0.85 ± 0.2^b
Ethyl lactate	1427	MS	26.23 ± 5.2^b	8.19 ± 0.03^d	67.78 ± 2.1^a	17.86 ± 3.2^c
Ethyl caprylate	1435	MS, RI	55.70 ± 3.9^a	39.94 ± 1.9^c	47.34 ± 0.8^b	25.01 ± 2.7^d
Propyleneacetate	1526	MS, RI	1.91 ± 0.1^b	147.06 ± 3.2^a	4.91 ± 1.1^b	1.75 ± 0.1^b
Glycol diacetate	1535	MS, RI	4.03 ± 0.8^b	45.02 ± 2.1^a	4.30 ± 1.2^b	1.23 ± 0.2^c
Ethyl caprate	1638	MS, RI	3.44 ± 0.6^b	4.80 ± 1.7^b	3.91 ± 1.8^b	15.54 ± 2.5^a
Phenethyl acetate	1815	MS, RI	212.17 ± 24.7^c	1750.72 ± 57.2^a	154.59 ± 25.8^c	319.56 ± 16.4^b
Phenethyl butyrate	1958	MS, RI	2.88 ± 0.8^b	208.45 ± 24.8^a	1.40 ± 0.3^b	0.28 ± 0.1^b
D-(-)-Pantolactone	2029	MS, RI	0.49 ± 0.1^b	18.21 ± 1.9^a	0.50 ± 0.1^b	nd
5-Decanolide	2194	MS, RI	1.46 ± 0.2^c	7.34 ± 0.3^a	nd	2.27 ± 0.2^b
Ketones
2-Heptanone	1078	MS, RI	13.97 ± 3.2^b	14.54 ± 2.8^b	49.30 ± 4.2^a	15.40 ± 0.8^b
Acetoin	1284	MS, RI	85.55 ± 9.4^b	8.47 ± 1.9^d	154.31 ± 5.8^a	47.32 ± 6.3^c
6-Methyl-5-hepten-2-one	1338	MS, RI	0.93 ± 0.1^c	13.27 ± 2.6^a	9.04 ± 0.3^b	8.62 ± 1.4^b
2-Non-anone	1390	MS, RI	12.18 ± 1.2^c	54.90 ± 4.2^a	27.41 ± 3.9^b	28.94 ± 2.8^b

¹Data are mean ± SD of three replicate analyses (n = 3). ^a–dMeans with different superscripts within the same row are significantly (P < 0.05) different. ²Control, KmC, PkC, and PfC represent samples collected on 40 days. ^ndMeans not detected. IA, identification approach.