Optimization of “Zaoheibao” wine fermentation process and analysis of aroma substances

Figures & data

Figure 1. Fermentation process from the “Zaoheibao” grape fruits to wine.

Table 1. Level table of the orthogonal test factors.

Level	SO2 (mg/L)	Yeast (mg/L)	Fermentation time (days)
1	20	100	2
2	30	150	6
3	40	200	10

Table 2. Table of orthogonal test analysis.

Treatment No.	A (SO2)	B (Yeast)	C (Fermentation time)
1	1	1	1
2	1	2	2
3	1	3	3
4	2	1	3
5	2	2	1
6	2	3	2
7	3	1	2
8	3	2	3
9	3	3	1

Table 3. Orthogonal test results for “Zaoheibao” wine.

Treatment No.	A(SO2)	B (Yeast)	C (Fermentation time)	Blank	Relative content of esters (%)
1	1	1	1	2	22.42
2	1	2	2	2	26.23
3	1	3	3	2	34.18
4	2	1	3	3	23.69
5	2	2	1	3	31.57
6	2	3	2	1	45.59
7	3	1	2	1	20.20
8	3	2	3	1	22.13
9	3	3	1	3	27.26
mean1	27.61	22.1	27.08	29.31
mean2	33.62	26	30.67	27.61
mean3	23.2	35.68	26.67	27.50
R	10.42	13.58	4	1.81

Figure 2. Effect of different factors on the generation of ester volatile aroma compounds during fermentation of “Zaoheibao” wine. Amount of yeast (a); SO₂ amount (b); fermentation time (c). Note: A, B, C, D indicate significant differences (p < 0.01).

Table 4. ANOVA of the orthogonal test for “Zaoheibao” wine.

Source of variance	Sum of squared deviations (SS)	Degrees of freedom (df)	Mean square (MS)	F	P
SO2 amount	164.13	2	82.065	5.627	0.15
Yeast amount	286.45	2	143.225	9.82	0.09
Fermentation cycle	29.11	2	14.555	0.09	0.50
Error	29.17	3	14.585
Variation	508.86	8
R^2=0.943

Note: Source of variance represents the total variance of all observations, including the inter-treatment variation and error. SS represents the sum of the total square of the total variation of all observations. Degrees of freedom are defined as df = n-1 (n represents the number of levels for each factor). MS represents the degree of variation of observations, MS = SS/df.

Table 5. Composition of volatile aroma substances (in %) in “Zaoheibao” wine, as determined from the orthogonal test.

Aroma substance	Juice and treatments										Odor description
	0	1	2	3	4	5	6	7	8	9
Ethyl palmitate	0.01	–	0.01	–	0.02	0.01	0.01	0.01	0.01	0.01	Wax, fruit and cream
Ethyl hexanoate	1.06	4.7	4.55	4.14	3.88	5.5	12.89	4.66	4.36	5.73	Green apple, floral, violet
Ethyl laurate	–	–	–	–	–	0.02	–	–	–	–	Sweet, floral, fruity, cheese
Ethyl isovalerate	–	–	0.02	0.01	–	–	–	–	–	–	Banana, sweet fruit
Isoamyl acetate	0.95	1.75	7.93	3.5	6.44	10.15	22.81	2.95	6.66	8.34	Banana, sweet fruit
Isobutyl acetate	0.07	0.06	0.17	0.16	0.17	0.22	0.49	0.1	0.17	0.14	Strawberry, fruity, floral
Ethyl acetate	27.28	6.03	7.06	19.66	7.07	9.19	5.43	6.23	6.13	4.8	Fruity, sweet
Hexyl acetate	–	–	0.05	–	0.02	0.09	0.32	–	–	0.06	Fruity, pear
Ethyl octanoate	0.36	6.15	4.38	2.62	3.48	4.09	2.67	4.14	3.06	4.83	Pineapple, pear, floral
Crystal violet lactone	–	–	–	–	–	0.02	0.01	–	–	–	–
Ethyl nonanoate	–	0.02	–	0.01	–	–	0.02	0.02	0.04	0.01	Fruit, banana
Ethyl caprate	0.18	3.3	1.62	0.58	2.24	1.58	0.46	1.65	1.61	2.84	Fruity, fat
Trans-4-decenoic acid, ethyl ester	–	0.04	–	–	–	0.01	–	–	–	–	Wax, pear, leathery
Ethyl butyrate	0.09	0.35	0.43	0.39	0.36	0.68	0.48	0.43	0.08	0.49	Cranberry, strawberry, fruity
Ethyl propionate	–	–	–	3.1	–	–	–	–	–	–	Pineapple
Isoamyl n-octanoate	0.02	0.02	0.01	0.01	0.01	0.01	–	0.01	0.01	0.01	Brandy aroma, sweet
Isoamyl alcohol	31.95	27.89	0.02	0.06	28.33	28.85	0.01	29.11	30.59	27.58	Mellow, pungent, bitter
Ethanol	0.09	0.57	0.05	–	0.71	0.18	0.02	0.49	0.22	1.19	Alcohol
Linalool	0.09	0.33	0.15	0.29	0.24	0.16	0.32	0.29	0.29	0.17	Musk, floral, fruity
α-Terpineol	–	–	–	0.1	–	–	–	–	–	–	Haitong flowers, sweet lilac, lily of the valley
2,3-Butanediol	–	–	–	0.19	–	0.1	–	0.01	–	–	Butter, cheese
(2R,3R)-(−)-2,3-butanediol	–	–	–	0.04	–	–	0.01	–	–	–	Butter, cheese
1-Pentanol	–	0.02	–	–	–	–	–	–	–	–	Bitter almond, fat
Phenethyl alcohol	–	–	–	–	–	0.05	–	–	–	–	Sweet rose
2-Cetyl alcohol	–	–	–	–	–	0.01	–	–	–	–	–
Oxalic acid	29.79	–	24.34	18.1	30.02	20.7	17.92	28.32	28.15	27.94	–
N-Benzoyl-L-isoleucine	–	–	33.79	30.64	–	–	20.33	–	–	–	–
N^6-Anisoyl adenylate	–	0.42	0.37	0.5	0.5	0.02	0.38	0.55	0.52	0.36	–
2-(Aminooxy)acetic acid	–	26.19	0.11	0.64	0.07	–	0.14	0.22	0.09	–	–
L-homocysteine	–	–	–	–	–	0.01	–	–	–	–	–
2,4-Di-tert-butylphenol	–	–	–	0.02	–	–	–	–	–	–	–
3,5-Di-tert-butylphenol	–	–	0.01	–	–	–	–	–	–	–	–
Phenol	1.02	–	–	–	0.18	–	–	–	0.15	–	Special smell
2-Methyltetrahydrothiophene-3-one	0.02	–	0.06	0.08	0.05	–	–	–	0.05	0.04	–
4-Hydroxy-2-butanone	–	0.02	–	–	–	0.01	0.04	0.03	0.01	–	Cream, fat
3-Hydroxybutyraldehyde	–	–	0.01	–	0.01	–	–	–	0.01	–	–
Ethylbenzene	0.02	0.13	0.16	0.16	0.11	0.03	0.16	0.17	0.16	0.16	Fragrant smell
m-Xylene	–	–	–	–	0.49	–	0.65	–	–	–	–
o-Xylene	0.01	–	–	–	–	0.23	–	–	0.57	–	–
p-Xylene	0.05	0.62	0.76	0.85	0.11	0.94	0.1	0.86	0.24	0.77	Fragrant smell
1,3-Di-tert-butylbenzene	0.08	0.08	0.13	0.26	0.1	0.16	0.09	0.12	0.09	0.09	–
2,4-Dimethyl-1-heptene	–	–	–	1.01	–	0.19	–	–	–	–	–
1,1-Diethoxyethane	0.15	3.15	0.36	0.9	0.32	0.05	0.42	2.2	0.66	0.33	Fruity
2,5-Dimethylhexane-2,5-hydrogen peroxide	–	–	–	0.06	–	–	–	–	–	–	–
2,4,5-Trimethyl-1,3-dioxolane	0.13	1.25	0.22	0.82	0.08	–	–	0.7	0.09	–	–
4-Methyl-2-(2-methylpropenyl) tetrahydro-2H-pyran	–	0.02	–	0.06	–	–	0.01	0.02	–	0.01	–
2,5-Diethoxytetrahydrofuran	–	0.01	–	–	–	–	–	–	–	–	–

Note: T0, grape juice; T1–T9, wine (see Table 2); - represents not detected;- in the odor description indicates lack of information about odor in the known literature; the values in boldface indicate the highest values of isoamyl acetate, ethyl acetate and ethyl octanoate among the treatments.

Figure 3. “Zaoheibao” wine and grape juice main components. Note: Left panel, treatments (wine T1–T9; grape juice T0; see Table 2). Right panel, aroma substances.

Figure 4. Aroma substance and odor contour map of “Zaoheibao” wine based on the orthogonal test. Note: Treat 1–9 represent different treatments (various amounts of SO₂ and yeast starter and fermentation time; see Tables 1 and 2).