Table 2. Changes in volatile aroma compositions (%) of kefir during storage (1- 30 d)

Control MS MS1 MS2 MS3

1 30 1 30 1 30 1 30 1 30
1-Nonanol (CAS) n-Nonyl alcohol 0.22±0.01c 0.40±0.03bc 0.68±0.05a 0.52±0.02ab 0.77±0.09a 0.67±0.15a 0.64±0.08ab 0.59±0.01ab 0.71±0.13a 0.64±0.00ab
2-Undecanol n.d. 0.18±0.01d n.d. 0.25±0.00bc n.d. 0.28±0.04b n.d. 0.30±0.02ab 0.19±0.04cd 0.36±0.00a
Benzeneethanol (CAS) n.d. 0.37±0.03ab n.d. n.d. n.d. 0.40±0.04a n.d. 0.33±0.00bc n.d. 0.29±0.02c
1-Dodecanol (CAS) 0.22±0.0cd 0.14±0.01cd 0.60±0.49bc n.d. n.d. n.d. 2.36±0.16a 0.41±0.01cd 0.98±0.03b n.d.
Total (%) 2.12±0.07j 21.37±0.00e 9.55±0.00h 25.24±0.02a 9.19±0.03i 22.63±0.02d 10.57±0.02g 24.91±0.01b 10.97±0.02f 23.43±0.02c
Carbonyl compounds
Acetaldehyde (CAS) Ethanal 0.29±0.11cd 0.97±0.19ab 0.24±0.04d 0.66±0.07abcd 0.34±0.17bc 1.11±0.26a 0.37±0.01bcd 0.89±0.40abc 0.33±0.05bcd 0.63±0.12abcd
2-Propanone (CAS) Acetone 0.16±0.04a n.d. n.d. n.d. 0.11±0.01b n.d. 0.12±0.01ab n.d. 0.12±0.00ab n.d.
2,3-Butanedione (Diacthyl) 5.39±1.16a 0.62±0.09de 2.79±0.09bc n.d. 1.56±0.91cd n.d. 3.67±0.01b n.d. 5.34±0.00a n.d.
2,3-Pentanedione (CAS) 0.21±0.04d n.d. 0.32±0.03c n.d. 0.66±0.05a n.d. 0.46±0.00b n.d. 0.66±0.04a n.d.
2-Pentanone, 4-methyl- (CAS) 0.52±0.24cd 1.75±0.19a n.d. n.d. 1.18±0.30ab 1.17±0.05ab 0.98±0.04bc 1.09±0.12bc 1.00±0.22bc 1.43±0.21ab
Hexanal (CAS) n-Hexanal 0.42±0.02b 0.38±0.13b 1.33±0.33a 1.52±0.06a 1.67±0.39a 1.23±0.03a 1.84±0.23a 1.18±0.16a 1.66±0.26a 1.30±0.00a
2-Heptanone (CAS) Heptan-2-one 1.26±0.14a 0.14±0.01c 0.93±0.04b 0.12±0.00c 0.91±0.06b n.d. 0.78±0.11b n.d. 0.98±0.00b 0.14±0.01c
Heptanal 0.28±0.01a 0.12±0.01ab 0.21±0.01a 0.11±0.03ab 0.27±0.12a 0.10±0.00ab 0.25±0.11a n.d. 0.13±0.00ab n.d.
Dodecane n.d. 0.13±0.02bc 0.17±0.03abc 0.19±0.03bg 0.20±0.00ab 0.10±0.00c 0.14±0.00abc 0.21±0.03a 0.12±0.03bc 0.17±0.00abc
Furan, 2-pentyl- n.d. n.d. 1.21±0.03a 0.70±0.03cd 0.73±0.15cd 0.45±0.16d 0.81±0.15bcd 0.88±0.07abc 1.13±0.20ab 1.15±0.03ab
2-Butanone,3-hydroxy-(CAS) Acetoin 10.35±0.32ab 0.57±0.09d 11.02±0.58a n.d. 8.67±0.41c n.d. 8.16±0.23c n.d. 9.59±0.10b n.d.
Amyl methyl carbinol 0.26±0.03c 1.40±0.20a 0.18±0.01c 1.12±0.02ab 0.18±0.02c 1.08±0.15b 0.17±0.00c 1.13±0.05ab 0.22±0.01c 1.17±0.09ab
2-Heptenal, (Z)- (CAS) n.d. n.d. 0.72±0.03a 0.37±0.02bc 0.52±0.02b 0.31±0.05c 0.83±0.05a 0.28±0.02c 0.75±0.15a 0.32±0.01c
2-Nonanone(CAS) 1.27±0.04a n.d. 0.89±0.02b n.d. 0.83±0.04b n.d. 0.71±0.18b 0.17±0.03c 0.89±0.13b n.d.
Nonanal (CAS) n-Nonanal 1.58±0.08a 0.48±0.20cd 1.09±0.03b 0.62±0.02c 0.17±0.03e 0.31±0.06de 0.39±0.01cd n.d. 0.54±0.05cd n.d.
2-Octenal, (E)- n.d. n.d. 0.48±0.02a 0.25±0.01b n.d. 0.26±0.05b 0.43±0.04a 0.22±0.02b 0.49±0.10a 0.21±0.00b
2-Nonenal, (E)- (CAS) 0.26±0.01c 0.30±0.00b 0.19±0.03d n.d. n.d. n.d. n.d. n.d. 0.42±0.03a n.d.
Nonyl methyl ketone 0.80±0.05a 0.18±0.01d 0.63±0.00bc n.d. n.d. n.d. 0.52±0.12c n.d. 0.67±0.01ab n.d.
2,4-Decadienal, (E,E)- n.d. n.d. 1.12±0.06a 0.32±0.02bc 0.90±0.05a n.d. 1.33±0.26a 0.42±0.02b 1.09±0.21a 0.32±0.02bc
2-Tridecanone (CAS) 0.39±0.01a 0.16±0.02b n.d. n.d. 0.34±0.02a 0.26±0.07ab 0.26±0.09ab n.d. 0.29±0.06ab 0.17±0.03b
Decalactone <delta-> 0.87±0.01a 0.50±0.06b 0.56±0.04b 0.53±0.01b 0.60±0.05b 0.56±0.06b 0.51±0.13b 0.54±0.01b 0.43±0.01b 0.61±0.03b
Dodecalactone <delta-> 0.72±0.05a 0.63±0.03a n.d. 0.70±0.08a 0.69±0.01a 0.65±0.06a n.d. 0.61±0.02a 0.55±0.11a 0.63±0.07a
Benzaldehyde (CAS) Phenylmethanal 1.61±0.27a 0.88±0.06b 0.61±0.10bc 0.41±0.00c 1.74±0.23a 0.34±0.02cd 1.75±0.07a n.d. 1.68±0:07a 0.23±0.00cd
Total (%) 26.66±0.02b 7.36±0.02f 24.72±0.01c 6.61±0.05h 22.36±0.04e 6.95±0.03g 24.56±0.02d 6.49±0.02h 28.99±0.07a 7.31±0.03f