Evaluation of Volatile Compounds during the Fermentation Process of Yogurts by Streptococcus thermophilus Based on Odor Activity Value and Heat Map Analysis

Table 2

OAVs of volatile compounds in yogurt fermented by S. thermophilus at different times.

Compound names	Odor descriptor	Odor threshold (mg·kg^−1)	OAV
			0 h	1.5 h	3.0 h	4.5 h	6.0 h
Aldehydes
Benzaldehyde	Almond, burnt sugar^3	0.35	3.8	5.3	5.8	9.2	10.5
Octanal	Fat, lemon, green^3	0.0009	1608.2	1831.1	1661.1	842.6	1423.4
Benzeneacetaldehyde	Sweet, flora^24	0.004	0.0	0.0	315.3	0.0	0.0
Nonanal	Sweet, floral, citrus, grass^3	0.04	213.4	106.9	83.4	41.9	86.9
Decanal	Fatty^3	0.03	78.3	39.9	38.0	42.5	0.0
(E)-2-Decenal	Fatty, waxy, green^24	0.001	0.0	640.7	0.0	0.0	0.0
Undecanal	Fatty^3	0.01	0.0	0.0	0.0	0.0	255.7
(E,E)-2,4-Decadienal	Fatty, green^24	0.0001	22156.6	14623.5	17060.5	17810.2	22278.7
Dodecanal	Soapy, waxy, citrus^24	0.0015	5836.5	3535.7	4192.9	615.0	0.0
Ketones
2-Heptanone	Fresh cream^25	0.14	386.6	404.1	466.1	437.0	513.1
2-Nonanone	Grass, fruity, floral^25	0.08	808.4	816.7	994.0	760.5	833.9
2-Nonen-4-one	Fruity, floral^3	0.0009	0.0	0.0	0.0	3391.7	2870.4
2-Decanone	Sweet, waxy^3	0.08	56.5	42.3	44.2	0.0	0.0
2-Undecanone	Orange, grass, fresh^25	0.08	1102.6	1054.7	1427.2	482.7	572.3
2-Dodecanone	Orange, grass, fresh^24	0.08	24.8	28.3	34.8	0.0	0.0
Acids
Hexanoic acid	Spicy, rancidity^25	1.84	0.0	0.0	0.0	2.8	16.4
Octanoic acid	Chess, sweaty^25	1.9	0.0	0.3	0.4	29.4	78.6
Decanoic acid	Rancid^3	3	0.0	0.0	0.9	23.6	260.7
Undecanoic acid	Rancid^24	10	0.0	0.0	0.0	1.0	1.6
Dodecanoic acid	Rancid^24	10	1.1	0.2	0.6	6.7	56.4
Tridecanoic acid	Rancid^24	10	0.0	0.0	0.0	0.0	0.6
Tetradecanoic acid	Rancid^24	10	0.1	0.5	2.1	4.2	30.0
Benzene derivatives
Ethylbenzene	Gasoline^24	0.2	19.9	26.2	27.2	26.4	27.7
p-Xylene	Phenolic^24	1	13.2	15.1	13.5	13.6	13.4
Styrene	Sweet, balsamic^24	0.05	254.2	245.5	238.7	203.9	220.9
Naphthalene	Phenolic^24	0.006	190.6	144.0	119.1	166.0	190.0
1-Methyl-naphthalene	Phenolic^24	0.0075	465.1	266.7	278.4	301.4	0.0
Other compounds
Diethyl disulfide	Cabbage, sulfide, gasoline^25	0.01	0.0	293.0	310.7	0.0	0.0
2-Pentyl-furan	Green, fat^3	0.006	364.9	0.0	0.0	0.0	0.0
Limonene	Orange, mint^25	0.2	18.4	16.6	16.2	6.2	6.3

Odor description and threshold were provided in references [3, 24, 25].