Table 4. Volatile components of TVPH and tuna viscera flavor enhancer

Component	RI	Concentration (ppm)
Component	RI	TVPH	Trt A	Trt B	Trt C	Trt D	Trt E	Trt F	Trt G
Alcohols
2-Furanmethanol	854		0.42 ± 0.07^ab	0.47 ± 0.06^b	0.47 ± 0.05^b	0.40 ± 0.03^ab	0.41 ± 0.01^ab	0.35 ± 0.05^a	0.34 ± 0.05^a
21-Octen-3-ol^ns	979	0.01 ± 0.00	0.006 ± 0.00	0.01 ± 0.00	0.01 ± 0.00	0.01 ± 0.00	0.01 ± 0.00	0.007 ± 0.00	0.006 ± 0.00
22-Ethyl-1-hexanol^ns	1,029		0.007 ± 0.00	0.004 ± 0.00	0.005 ± 0.00	0.004 ± 0.00			0.003 ± 0.00
Aldehydes
2-Methylpropanal	543		0.03 ± 0.01^a	0.05 ± 0.01^b	0.03 ± 0.00^a	0.03 ± 0.00^a	0.04 ± 0.01^ab	0.04 ± 0.00^ab
3-Methylbutanal	643	0.02 ± 0.00^a	0.31 ± 0.02^d	0.25 ± 0.02^cd	0.25 ± 0.14^cd	0.21 ± 0.02^cd	0.17 ± 0.02^bc	0.16 ± 0.05^bc	0.09 ± 0.04^ab
2-Methylbutanal	653	0.01 ± 0.00^a	0.17 ± 0.01^bc	0.36 ± 0.01^f	0.24 ± 0.08^cd	0.27 ± 0.04^de	0.34 ± 0.08^ef	0.16 ± 0.03^bc	0.09 ± 0.03^b
Hexanal	800	0.076 ± 0.02^b	0.009 ± 0.00^a	0.005 ± 0.00^a	0.004 ± 0.00^a		0.004 ± 0.00^a	0.005 ± 0.00^a	0.004 ± 0.00^a
(Z)-4-heptenal	900	0.02 ± 0.00^c	0.008 ± 0.00^b	0.002 ± 0.00^a	0.002 ± 0.00^a	0.002 ± 0.00^a	0.002 ± 0.00^a	0.003 ± 0.00^a	0.002 ± 0.00^a
Benzaldehyde	956	0.03 ± 0.02^b	0.02 ± 0.00^ab	0.02 ± 0.00^a	0.02 ± 0.00^ab	0.02 ± 0.00^ab	0.02 ± 0.00^ab	0.01 ± 0.00^a	0.02 ± 0.00^a
Benzene acetaldehyde	1,041	0.01 ± 0.00^a	0.08 ± 0.01^b	0.09 ± 0.02^b	0.09 ± 0.01^b	0.09 ± 0.01^b	0.09 ± 0.02^b	0.07 ± 0.02^b	0.09 ± 0.01^b
Ketones
2-Butanone	593		0.02 ± 0.01^abc	0.02 ± 0.01^abc	0.02 ± 0.01^bc	0.01 ± 0.00^ab	0.03 ± 0.01^c	0.02 ± 0.01^bc	0.009 ± 0.00^a
3-Hexanone	782						0.002 ± 0.00
5-Methyl-2-hexanone	843			0.001 ± 0.00^a	0.001 ± 0.00^a	0.001 ± 0.00^a	0.003 ± 0.00^b		0.001 ± 0.00^a
2-Heptanone	890		0.01 ± 0.00^c	0.01 ± 0.00^c	0.01 ± 0.00^b	0.01 ± 0.00^c	0.01 ± 0.00^c	0.008 ± 0.00^ab	0.006 ± 0.00^a
Acetophenone	1,064	0.001 ± 0.00^a	0.003 ± 0.00^a	0.005 ± 0.00^a	0.005 ± 0.00^a	0.01 ± 0.00^b	0.007 ± 0.00^ab	0.006 ± 0.00^a	0.012 ± 0.00^b
Pyrazines
Methylpyrazine	819		0.007 ± 0.00^a	0.01 ± 0.00^b	0.01 ± 0.01^b	0.01 ± 0.00^b	0.01 ± 0.00^b	0.01 ± 0.01^b	0.01 ± 0.00^b
Ethylpyrazine^ns	913		0.003 ± 0.00	0.007 ± 0.00	0.007 ± 0.01	0.01 ± 0.01	0.008 ± 0.00	0.008 ± 0.00	0.009 ± 0.01
2,5-Dimethylpyrazine	910		0.014 ± 0.00^a	0.054 ± 0.01^bc	0.061 ± 0.01^bcd	0.05 ± 0.01^bcd	0.07 ± 0.00^d	0.04 ± 0.01^b	0.07 ± 0.01^cd
2,3-Dimethylpyrazine^ns	917		0.002 ± 0.00	0.003 ± 0.00	0.002 ± 0.00	0.004 ± 0.00	0.002 ± 0.00	0.002 ± 0.00	0.002 ± 0.00
Trimethylpyrazine	1,002		0.04 ± 0.00^a		0.06 ± 0.00^b
2,5-Dimethyl-3-ethylpyrazine^ns	1,078		0.009 ± 0.01	0.01 ± 0.00	0.01 ± 0.01	0.01 ± 0.00	0.01 ± 0.01	0.01 ± 0.00	0.01 ± 0.00
Sulfurs
Dimethyl disulfide	737		0.006 ± 0.00^a	0.01 ± 0.00^b	0.01 ± 0.00^b	0.01 ± 0.00^ab	0.01 ± 0.01^b	0.01 ± 0.00^ab	0.01 ± 0.01^ab
Methional	905	0.02 ± 0.00^a	0.06 ± 0.01^bc	0.06 ± 0.01^bc	0.06 ± 0.00^bc	0.07 ± 0.01^bc	0.06 ± 0.01^b	0.08 ± 0.02^c	0.08 ± 0.01^c
Dimethyl trisulfide	963		0.003 ± 0.00^a	0.009 ± 0.00^c	0.008 ± 0.00^bc	0.005 ± 0.00^ab	0.01 ± 0.00^c	0.004 ± 0.00^ab	0.008 ± 0.00^bc
2-Acetylthiazole	1,017		0.002 ± 0.00^ab	0.003 ± 0.00^ab	0.002 ± 0.00^ab	0.004 ± 0.00^b	0.003 ± 0.00^ab	0.001 ± 0.00^a	0.001 ± 0.00^a

Values are presented as mean ± SD (n = 3).
Different lowercase letters in the same row represent a significant difference (p < 0.05) of mean between treatments.
TVPH, tuna viscera protein hydrolysate; RI, retention index; Trt A, Treatment A; Trt B, Treatment B; Trt C, Treatment C; Trt D, Treatment D; Trt E, Treatment E; Trt F, Treatment F; Trt G, Treatment G; ns, not significant.