Flavor characteristics of the juices from fresh market tomatoes differentiated from those from processing tomatoes by combined analysis of volatile profiles with sensory evaluation

Figures & data

Table 1. Characteristics of the tomato juice samples used in this study.

Sample ID	Variety type used for^a	Container	Brix	Acidity (w/v %)	pH	Lycopene content (mg%)	Viscosity (mPas^b)
A	Processing	Can	5.1	0.44	4.32	12.3	468
B	Processing	Can	6.0	0.53	4.26	14.4	648
C	Processing	Can	5.3	0.34	4.40	12.3	376
D	Processing	Bottle	5.3	0.38	4.30	14.1	630
E	Processing	Can	5.2	0.43	4.35	12.2	462
F	Fresh market (var. Momotaro)	Can	7.0	0.39	4.36	6.0	659
G	Processing	Can	5.3	0.39	4.45	11.5	428
H	Processing	Can	5.6	0.38	4.34	4.9	408
I	Processing	Can	5.6	0.38	4.40	9.4	616
J	Fresh market	Bottle	6.4	0.49	4.14	7.0	572
K	Fresh market (var. Momotaro)	Can	6.6	0.44	4.21	3.5	441
L	Processing	Can	4.8	0.31	4.25	12.1	164
M	Processing	Can	4.8	0.37	4.33	13.1	410
N	Processing	Can	4.8	0.37	4.35	8.6	259
O	Processing	Can	5.0	0.37	4.31	11.6	374

^a Fresh market tomato and processing tomato are the tomato varieties usually consumed at fresh state and after cooked, respectively.

^b Measured using a b-type viscometer.

Table 2. Compounds frequently detected as high VIP scores (>1.0) and their contribution to each sensory descriptor, lycopene content and Brix.

	2-methylbutanal	hexenal	furfural	cis-3-hexenol	methional	6-methyl-5-hepten-2-one	o-cymene	2-isobutylthiazole	2-methylbenzonitrile	1-nitro-phenylethane	geranylacetone
Positives^a	13	14	12	16	12	17	13	14	14	13	13
Negatives^a	15	14	18	13	16	13	17	14	14	14	14
Stuffy_A^c				－			＋		＋		＋
Fresh tomato_A	－^b	＋	－	＋	－	＋	－	＋	＋	＋	＋
Whole processed tomato_A	＋^b	－	＋	－	＋	－	＋	－	－	－	－
Fresh grass_A	－	＋	－	＋	－	＋	－	＋	＋	＋	＋
Grated carrot_A	＋	－	＋	－	＋	－	＋	－	－	－	－
Earthy_A	－		－			＋	－
Fresh cut grass_A	－	＋	－	＋	－	＋	－	＋	＋	＋	＋
Tabasco_A			－	＋			－	＋
Herb_A	－	＋	－	＋	－	＋	－	＋	＋	＋	＋
Sweet_A	－	＋	－	＋	－	＋	－	＋	＋	＋	＋
Peach_A	＋	－	＋	－	＋	－	＋	－	－	－	－
Orange_A	＋	－	＋	－	＋	－	＋	－	－	－	－
Lemon_A				＋			－
Apple_A	＋	－	＋		＋	－		－	－	－	－
Sour_A		＋	－	＋	－	＋	－	＋
Metallic_A	＋	－	＋	－	＋	－	＋	－	－	－	－
Vinyl_A		－	－		－	－		－	－	－	－
Green tea_A	－		－		－	＋	－
Stuffy_F^d						＋	＋				＋
Fresh tomato_F	－	＋	－	＋	－	＋	－	＋	＋	＋
Whole processed tomato_F	＋	－		－			＋	－
Fresh grass_F	－	＋	－	＋	－	＋	－	＋	＋	＋	＋
Celery_F	－	＋	－	＋	－	＋	－	＋	＋	＋	＋
Grated carrot_F	＋	－	＋	－	＋	－	＋	－	－	－	－
Fresh cut grass_F	－	＋	－	＋	－	＋	－	＋	＋	＋	＋
Tabasco_F											－
Herb_F	－	＋	－	＋	－	＋	－	＋	＋	＋	＋
Peach_F	＋	－	＋	－	＋	－	＋	－	－	－	－
Orange juice_F	＋	－	＋	－	＋	－	＋	－	－	－	－
Lemon_F				＋					－	－
Apple_F	＋	－	＋	－	＋	－	＋	－	－	－	－
Metallic_F	＋	－	＋	－	＋	－		－	－	－	－
Green tea_F	－	＋	－		－	＋			＋	＋	＋
Fresh tomato aftertaste_F	－	＋	－	＋	－	＋	－	＋	＋	＋
Lycopene	－	＋	－	＋	－	＋	－	＋	＋	＋	＋
Brix	＋	－	＋	－	＋	－	＋	－	－	－	－

^a Total number of descriptors positively or negatively contributed by compounds.

^b Labeled + and – mean statistically positive and negative contribution, respectively.

^c,d Aroma or flavor of sensory descriptors are abbreviated as “A” or “F”, respectively.

Fig. 1. Principal components analysis of volatile compounds. Score plot (A) and loading plot (B) for the detected volatile compounds are shown.

Notes: Pareto scaling was used for analysis. EtAc, ethyl acetate; GeraAc, geranyl acetate; Mes, dimethyl sulfide; MeSal, methyl salicylate; 6-MetHep, 6-methyl-5-hepten-2-one; NitroMetBut, 3-methyl-1-nitrobutane; NitrophenylEt, 1-nitro-2-phenylethane; PhenylAc, phenylacetaldehyde; PhenylEt, 2-phenylethanol; 2-Met-2-But, 2-methyl-2-butenal; 2-MetBenNit; 2-methylbenzonitrile.

Fig. 2. Relative peak intensities of ethyl acetate (A), dimethyl sulfide (B), cis-3-hexenol (C) and furfural (D) among 15 tomato juices.

Notes: The y-axis indicates the peak intensity of specific m/z for each compound; ethyl acetate (m/z 43), dimethyl sulfide (m/z 62), cis-3-hexenol (m/z 67), and furfural (m/z 96).

Fig. 3. Hierarchical clustering of tomato juices.

Note: The z-score for each detected volatile was used for analysis.

Fig. 4. Correlation between apocarotenoid volatiles and lycopene content, and the pathway of synthesis of apocarotenoids from lycopene by carotenoid cleavage dioxygenase in tomato.

Notes: Correlations between the contents of (A) 6-methyl-5-hepten-2-one and geranylacetone, (B) 6-methyl-5-hepten-2-one and lycopene, and (C) geranylacetone and lycopene. (D) Degradation of lycopene to 6-methyl-5-hepten-2-one and geranylacetone by carotenoid cleavage dioxygenase.

Fig. 5. Correlation analysis of the PC1 values for the volatile compounds (x-axis) and sensory descriptors (y-axis) determined for the tomato juice samples.

Notes: Pareto scaling was performed for both analyses.

Fig. 6. The first predictive component values under score and loading plots by O2PLS analysis using volatile profiles (X-variables) and sensory scores by QDA analysis (Y-variables).

Notes: Unit valance scaling was used for the analysis. (A) Score plot values, (B) loading plot values for sensory descriptions, and (C) loading plot values for volatile compounds. The score t[1] indicates the largest variation summarizing the X-variables based on the information of Y-variables. The loadings p and q correspond to the covariance between X-variables to the predictive score vectors, and between Y-variables to the predictive score vectors, respectively.