Table 4.

Concentration (μg/g) of volatile aroma profiles in cooked bellies as affected fat level

Items	Retention time (min)	Fat level			Identify method1)	Odor descriptors from literatures	Source	References
		Low fat	Medium fat	High fat
Aldehydes
Propanal	1.723	0.04±0.01	0.04±0.01	0.06±0.01	MS+STD	Sweet, caramel and alcohol	Beef	[36]
2-ethylhexanal	2.167	0.03±0.01a	0.02±0.00ab	0.01±0.01b	MS+STD	NF
3-methybutanal	2.72	0.05±0.01a	0.03±0.01b	0.02±0.01b	MS+STD	Meaty and fishy	Beef	[36,37]
2-methylbutanal	2.829	0.09±0.02a	0.05±0.01b	0.03±0.01b	MS+STD	Nutty and onion	Beef	[37]
Hexanal	6.121	3.12±0.15a	2.75±0.07b	2.56±0.05b	MS+STD	Green, fatty, fruity, aldehyde, and rancid	Beef, pork	[36,37]
Heptanal	9.261	0.17±0.03	0.13±0.03	0.16±0.01	MS+STD	Green, fatty, oily, oily, fatty, fruity, rancid and unpleasant	Beef, chicken	[37,38]
2-Heptenal	10.755	0.04±0.01	0.03±0.01	0.03±0.02	MS+STD	Soapy, fatty, almond, fishy and unpleasant	Beef	[35]
Benzaldehyde	10.873	0.04±0.01	0.05±0.00	0.06±0.01	MS+STD	Almond oil, bitter almond, burning aromatic taste	beef	[35]
Octanal	11.915	0.18±0.06b	0.20±0.03ab	0.29±0.05a	MS+STD	Sweet, fatty, fruity, lemon, green and oily	beef	[35,37]
Benzenacetaldehyde	12.874	0.01±0.00	0.01±0.00	0.02±0.01	MS+STD	NF
E,2-octenal	13.19	0.02±0.01	0.02±0.01	0.02±0.00	MS+STD	Fatty, nutty and green	Beef	[35,36]
Nonanal	14.198	0.14±0.01c	0.20±0.00b	0.26±0.03a	MS+STD	Sweet, fat, fruity and citrus	Beef	[35,36]
E,2-nonenal	15.33	0.09±0.02	0.08±0.02	0.19±0.15	MS+STD	Fatty, aldehyde, nutty and cucumber	Beef	[35,36]
Alcohols
1-penten-3-ol	3.067	0.01±0.00	0.01±0.00	0.01±0.00	MS+STD	NF
4-amino-1-hexanol	3.302	0.19±0.02	0.24±0.02	0.23±0.04	MS	NF
1-Pentanol	5.026	0.16±0.01	0.11±0.00	0.12±0.02	MS+STD	Roasted meat, mild odor, fruit	Beef	[35,38]
1-Heptanol	11.112	0.01±0.00b	0.01±0.00b	0.02±0.01a	MS+STD	Fragrant, woody, oily, green, fatty, winey, sap and herb	Beef	[35]
1-Octen-3-ol	11.356	0.09±0.02	0.05±0.02	0.09±0.05	MS+STD	Mushrooms	Beef	[35]
2-ethyl-1-hexanol	12.588	0.03±0.01	0.03±0.00	0.03±0.00	MS+STD	NF
Hydrocarbons
Toluene	4.929	0.01±0.00	0.01±0.00	0.01±0.00	MS+STD	NF
1,3-dimethyl benzene	7.982	0.01±0.00	0.01.±.0.00	0.02±0.00	MS	NF
Xylene	8.915	0.07±0.03	0.07±0.05	0.08±0.03	MS	NF
2,4-dimethylhexane	13.029	0.03±0.01	0.03±0.00	0.03±0.00	MS	NF
Benzoic acid	15.433	0.06±0.01	0.06±0.01	0.06±0.03	MS+STD	NF
Sulfur- and nitrogen-containing compounds
Carbon disulfide	1.862	0.01±0.00	0.01±0.00	0.01±0.00	MS	NF
2,5-dimethyl pyrazine	9.558	0.03±0.00a	0.01±0.00b	0.02±0.00b	MS+STD	Roasty and toasty	Beef, pork	[32,39]
4-methylthiazole	11.475	0.23±0.01a	0.19±0.01ab	0.16±0.02b	MS+STD	Roasty and meaty	Beef, pork	[39,40]
2-ethyl-3,5-dimethylpyrazine	13.575	0.04±0.00a	0.02±0.00b	0.02±0.00b	MS	Roasty and toasty	Beef, pork	[32,37,39]
Furans
2-pentylfuran	11.581	0.25±0.09	0.29±0.02	0.24±0.07	MS+STD	Green bean and butter	Beef	[35]
2-n-Octylfuran	17.889	0.04±0.02	0.03±0.00	0.02±0.01	MS+STD	NF

NF, not found.

¹⁾Identification method: the compounds were identified by mass spectra (MS) from library or external standard (STD).

^a–cMeans within a row with different letters are different at p<0.05.