Physicochemical properties and bioactive compounds of fermented pomegranate juice as affected by high-pressure processing and thermal treatment

Figures & data

Table 1. Sensory attributes and reference scores used for sensory evaluation of fermented pomegranate juice

Sensory attributes	Descriptions	Reference score
Color	The color is bright, pomegranate red and uniform	4–5
	The color is slightly reddish, uneven, and dull	2–3
	The color is brownish yellow, no pomegranate red, and uneven	0–1
Aroma	The aroma is unique and pure, sweet, and slightly flowers and fruits	4–5
	The aroma is rich and pure, slightly sweet, slightly flowers and fruits	2–3
	The aroma is light and impure, and the overall smell is uncoordinated	0–1
Flavor	The scent of juice is rich and unique, pomegranate, harmony and soft, and the aroma remains for a long time after drinking	4–5
	The scent of juice is light and pure, slightly pomegranate, but the residual time is short	2–3
	The scent of juice is light and impure, not obvious pomegranate, not harmony	0–1
Mouthfeel	Juice is moderate sweet and sour, and no bitter taste	4–5
	Juice is slightly sweet or slightly sour, and slightly bitter taste	2–3
	Juice is too sweet or too sour, and very bitter	0–1
Acceptability	Overall very satisfied, acceptable	4–5
	Satisfied, acceptable	2–3
	Unacceptable	0–1

Table 2. Microbial inactivation of fermented pomegranate juice by high pressure processing and thermal processing

Treatments conditions	Aerobic plate count (log10 N)/CFU/mL			Yeasts and molds (log10 N)/CFU/mL
	400 MPa	500 MPa	600 MPa	400 MPa	500 MPa	600 MPa
Unfermented	ND			ND
Untreated	4.16 ± 0.23	4.16 ± 0.23	4.16 ± 0.23	2.37 ± 0.23	2.37 ± 0.23	2.37 ± 0.23
65 °C/20 min	ND			ND
3 min	2.74 ± 0.17	2.43 ± 0.15	1.98 ± 0.12	1.21 ± 0.18	ND	ND
5 min	2.25 ± 0.21	1.46 ± 0.18	0.88 ± 0.16	ND	ND	ND
7 min	2.04 ± 0.11	1.01 ± 0.13	0.69 ± 0.09	ND	ND	ND
10 min	1.84 ± 0.20	0.91 ± 0.12	0.56 ± 0.06	ND	ND	ND

All data were the means ± SD, n = 3, ND = Not Detectable; Untreated: fermented but not pressure or thermal treated

The detection limit<100 CFU/mL.

Table 3. The Weibull model kinetic parameters of microbial inactivation of fermented pomegranate juice treated by high pressure processing

Pressure/MPa	b	n	R^2
400	0.99 ± 0.09	0.38 ± 0.05	0.993
500	1.19 ± 0.26	0.46 ± 0.11	0.965
600	1.66 ± 0.34	0.36 ± 0.11	0.965

Data b and n were the scale factors and shape factors.

Figure 1. Microbial inactivation of fermented pomegranate juice treated by high pressure processing fitting by the Weibull model

Table 4. Effects of thermal processing and high pressure processing on physicochemical parameters of fermented pomegranate juice

Treatment	L*	a*	b*	ΔE	pH	TSS	TA (%)
Untreated	8.45 ± 0.11^ab	1.10 ± 0.05^b	0.53 ± 0.05^f	–	3.64 ± 0.01^bc	21.48 ± 0.01^bc	3.79 ± 0.10^a
65 °C/20 min	8.52 ± 0.05^a	1.37 ± 0.05^a	0.77 ± 0.05^d	0.37 ± 0.04^d	3.65 ± 0.01^b	21.49 ± 0.00^abc	3.49 ± 0.07^c
400 MPa/10 min	8.30 ± 0.09^cd	0.74 ± 0.08^e	0.62 ± 0.04^e	0.40 ± 0.08^d	3.64 ± 0.01^bc	21.49 ± 0.01^abc	3.58 ± 0.02^bc
500 MPa/5 min	8.32 ± 0.08^bcd	0.95 ± 0.03^c	1.01 ± 0.03^b	0.52 ± 0.07^bc	3.64 ± 0.01^bc	21.48 ± 0.02^bc	3.72 ± 0.13^ab
500 MPa/7 min	8.24 ± 0.10^cde	0.84 ± 0.03^d	1.03 ± 0.05^b	0.60 ± 0.08^b	3.65 ± 0.01^b	21.48 ± 0.01^bc	3.56 ± 0.13^c
500 MPa/10 min	8.18 ± 0.10^de	0.83 ± 0.02^d	1.13 ± 0.02^a	0.71 ± 0.03^a	3.64 ± 0.01^bc	21.50 ± 0.01^ab	3.52 ± 0.03^a
600 MPa/3 min	8.37 ± 0.04^bc	0.88 ± 0.03^d	0.64 ± 0.06^e	0.26 ± 0.05^e	3.65 ± 0.01^b	21.51 ± 0.01^a	3.76 ± 0.03^a
600 MPa/5 min	8.29 ± 0.02^cde	0.87 ± 0.02^d	0.85 ± 0.05^cd	0.43 ± 0.02^cd	3.65 ± 0.01^b	21.48 ± 0.02^c	3.59 ± 0.11^bc
600 MPa/7 min	8.23 ± 0.09^cde	0.83 ± 0.02^d	0.89 ± 0.03^c	0.50 ± 0.05^c	3.66 ± 0.00^ab	21.49 ± 0.02^bc	3.54 ± 0.09^c
600 MPa/10 min	8.15 ± 0.03^e	0.82 ± 0.01^d	0.98 ± 0.04^b	0.61 ± 0.07^b	3.66 ± 0.01^ab	21.50 ± 0.01^ab	3.47 ± 0.04^c

Data are expressed as mean ± SD (n = 3). ^a-f Different letters in the same column indicate a significant difference (p ≤ 0.05). TSS: total soluble solids; TA: titratable acidity; untreated: fermented but not pressure or thermal treated.

Table 5. Effects of thermal processing and high pressure processing on total phenols, total flavonoids, anthocyanins and total antioxidant activity in fermented pomegranate juice

Treatment	Total phenols (mg/L)	Total flavonoids (mg/L)	Anthocyanins (mg/L)	Antioxidant activity (μM Trolox/L)
Untreated	803.34 ± 13.04^a	875.04 ± 4.59^a	41.30 ± 1.11^b	225.29 ± 4.74^a
65 °C/20min	585.75 ± 2.98^h	757.55 ± 3.86^cd	28.44 ± 0.54^f	200.08 ± 8.50^e
400 MPa/10 min	696.42 ± 4.37^d	761.90 ± 3.36^cd	38.46 ± 0.54^cd	210.36 ± 1.73^bc
500 MPa/5 min	772.34 ± 10.94^b	772.19 ± 4.18^c	40.19 ± 0.67^bc	211.18 ± 3.41^bc
500 MPa/7 min	701.78 ± 3.48^d	761.29 ± 3.49^cd	39.47 ± 0.42^cd	210.77 ± 4.53^bc
500 MPa/10 min	654.07 ± 8.84^f	699.58 ± 4.99^e	38.13 ± 1.55^d	209.67 ± 5.60^cd
600 MPa/3 min	783.41 ± 2.87^b	797.90 ± 3.93^b	39.52 ± 0.75^cd	216.03 ± 4.61^bc
600 MPa/5 min	726.41 ± 8.67^c	762.80 ± 2.10^cd	38.52 ± 0.26^cd	208.85 ± 2.34^cd
600 MPa/7 min	667.85 ± 6.05^e	739.02 ± 2.86^d	37.85 ± 0.70^d	208.24 ± 4.73^cd
600 MPa/10 min	611.51 ± 4.42^g	698.17 ± 2.15^e	35.68 ± 0.54^e	204.26 ± 5.55^de

Data are expressed as mean ± SD (n = 3). ^a-h Different letters in the same column indicate a significant difference (p ≤ 0.05). Untreated: fermented but not pressure or thermal treated.

Table 6. Pearson’s correlation analysis between different indices of fermented pomegranate juice

Treatments	Total phenols (mg/L)	Total flavonoids (mg/L)	Anthocyanins (mg/L)	Antioxidant activity (μM)
Total phenols	1
Total flavonoids	0.770**	1
Anthocyanins	0.818**	0.391	1
Antioxidant activity	0.875**	0.799**	0.792**	1

Data were analyzed by Pearson two-sided test, *Correlation is significant at p ≤ 0.05, and **Correlation is significant at p ≤ 0.01. The ‘*’ is used at upper right of the number.

Table 7. Effects of thermal processing and high pressure processing on volatile compounds in fermented pomegranate juice

Category	Compounds name	RC
		Unfermented	Untreated	65 °C /20 min	400 MPa/10 min	500 MPa/5 min	500 MPa/7 min
Aldehydes and Ketones	2,2-Dimethylhex-4-yn-3-one	1.15 ± 0.10^a	0.72 ± 0.30^b	0.44 ± 0.10^c	0.78 ± 0.10^b	0.79 ± 0.13^b	0.17 ± 0.03^d
	6-Methyl-5-hepten-2-one	5.92 ± 0.22^a	1.83 ± 0.35^b	1.48 ± 0.10^c	1.65 ± 0.14^bc	1.69 ± 0.16^bc	1.65 ± 0.16^bc
	3,4-Hexanedione	1.85 ± 0.20^a	1.48 ± 0.20^b	0.71 ± 0.10^d	1.18 ± 0.13^c	1.17 ± 0.22^c	1.13 ± 0.17^c
	Hex-4-yn-3-one	5.81 ± 0.13^a	0.58 ± 0.04^b	0.23 ± 0.06^b	0.42 ± 0.05^c	0.28 ± 0.03^b	0.37 ± 0.04^cd
	4-Methylhept-6-en-3-one	3.92 ± 0.20^a	1.86 ± 0.23^e	1.55 ± 0.13^f	2.60 ± 0.10^de	2.78 ± 0.15^c	3.44 ± 0.24^b
	2-Nonanone	1.66 ± 0.14^a	0.91 ± 0.20^b	0.82 ± 0.18^b	0.88 ± 0.08^b	0.75 ± 0.20^b	0.84 ± 0.12^b
	2-Heptnone	3.52 ± 0.06	ND	ND	ND	ND	ND
	2-Octanone	1.69 ± 0.11	ND	ND	ND	ND	ND
Alcohols	Trans-2,3-hexanediol	0.37 ± 0.05^f	3.19 ± 0.19^ab	3.41 ± 0.00^a	3.00 ± 0.00^bc	2.55 ± 0.03^de	2.81 ± 0.00^cd
	Trans-hexane-1,2-diol	0.41 ± 0.07^e	5.46 ± 0.47^a	3.40 ± 0.15^d	4.29 ± 0.00^c	4.70 ± 0.03^b	4.68 ± 0.00^b
	1,5-Hexadien-3-ol	0.34 ± 0.03^d	4.22 ± 0.06^a	3.75 ± 0.14^c	4.18 ± 0.08^a	4.17 ± 0.05^a	4.13 ± 0.09^ab
	1,3-Dioxolan-2-ylmethanol	2.65 ± 0.10^g	3.96 ± 0.20^a	3.15 ± 0.18^f	3.75 ± 0.22^ab	3.68 ± 0.10^bc	3.47 ± 0.06^cd
	3,3-Dimethyl-1-Butanol	1.38 ± 0.01^e	1.94 ± 0.03^a	1.62 ± 0.05^cd	1.71 ± 0.05^bc	1.74 ± 0.02^b	1.71 ± 0.06^bc
	1-(Furan-2-yl)but-3-ene-1,2-diol	ND	2.09 ± 0.02^a	1.06 ± 0.01^g	1.40 ± 0.08^e	1.58 ± 0.03^d	1.26 ± 0.12^f
	1-Butanol	0.15 ± 0.01^i	3.21 ± 0.02^a	2.49 ± 0.10^g	2.58 ± 0.00^ef	3.10 ± 0.03^b	2.61 ± 0.00^de
	2-Nonanol	1.01 ± 0.08^e	6.11 ± 0.19^a	4.32 ± 0.00^d	4.56 ± 0.23^bc	4.65 ± 0.10^b	4.59 ± 0.09^bc
	Phenylethyl Alcohol	ND	3.13 ± 0.02^a	2.58 ± 0.00^f	2.86 ± 0.02^d	3.01 ± 0.05^bc	3.03 ± 0.08^b
	2-Heptanol	0.14 ± 0.05^g	1.84 ± 0.01^e	1.20 ± 0.03^f	2.77 ± 0.05^bc	2.95 ± 0.07^ab	2.75 ± 0.00^cd
Esters	Ethyl Acetate	2.28 ± 0.06^c	20.87 ± 0.16^b	23.34 ± 0.28^a	21.05 ± 0.38^b	20.78 ± 0.25^b	20.84 ± 0.36^b
	Vinyl Sorbate	ND	0.10 ± 0.04	ND	ND	ND	ND
	Ethyl-2-methylbutyrate ester	ND	3.16 ± 0.00^b	3.34 ± 0.17^a	3.08 ± 0.06^bc	2.95 ± 0.00^c	3.00 ± 0.13^bc
	Ethyl butyrate	0.22 ± 0.02^c	4.54 ± 0.19^c	8.12 ± 0.24^a	5.48 ± 0.14^b	5.55 ± 0.16^b	5.61 ± 0.14^b
	Ethyl citrate	0.21 ± 0.02^h	1.07 ± 0.09^g	3.23 ± 0.08^a	2.21 ± 0.12^ef	2.45 ± 0.07^cd	2.64 ± 0.18^b
	Hexyl isovalerate	ND	0.71 ± 0.00^a	0.39 ± 0.05^b	0.29 ± 0.03^d	0.29 ± 0.03^d	0.34 ± 0.01^bcd
	Methyl 8-oxooctadecanoate	0.32 ± 0.04^e	1.98 ± 0.08^d	5.44 ± 0.39^a	2.72 ± 0.18^bc	2.52 ± 0.20^c	2.53 ± 0.00^c
	Ethyl hexanoate	0.66 ± 0.10^d	3.20 ± 0.32^c	4.20 ± 0.27^a	3.64 ± 0.19^bc	3.24 ± 0.18^bc	3.47 ± 0.18^bc
	Ethyl propanoate	ND	2.50 ± 0.32^a	1.71 ± 0.32^d	2.24 ± 0.00^abc	2.25 ± 0.12^abc	2.15 ± 0.03^bc
	Hexyl acetate	1.41 ± 0.21^e	3.36 ± 0.21^d	6.57 ± 0.64^a	4.32 ± 0.60^bc	4.24 ± 0.24^bc	4.56 ± 0.37^bc
Heterocyclic and aromatic compounds	2,6-Dimethylpyrazine	12.30 ± 0.44^a	2.30 ± 0.22^d	1.79 ± 0.10^e	3.76 ± 0.13^b	3.61 ± 0.12^bc	3.56 ± 0.10^bc
	2,3-Dihydro Benzofuran	3.61 ± 0.28^a	1.61 ± 0.19^b	0.90 ± 0.09^de	0.79 ± 0.06^e	0.98 ± 0.13^cde	1.04 ± 0.05^cd
	2,6-Lutidine	1.74 ± 0.26^a	0.65 ± 0.20^b	0.40 ± 0.09^d	0.57 ± 0.06^bc	0.40 ± 0.00^d	0.38 ± 0.08^d
	2-Heptyl-1,3-dioxolane	2.52 ± 0.15^a	0.89 ± 0.04^d	1.14 ± 0.15^cd	1.62 ± 0.08^b	1.30 ± 0.27^bcd	1.44 ± 0.30^bc
	Styrene	29.63 ± 0.58	ND	ND	ND	ND	ND
Acids	Azetidine-2-carboxylic acid	ND	0.58 ± 0.07^d	0.19 ± 0.10^e	0.58 ± 0.07^d	0.66 ± 0.04^cd	0.72 ± 0.02^c
	4-(Benzyloxy)-3-methoxy-2-nitrobenzoic acid	ND	0.11 ± 0.02	ND	ND	ND	ND
	Nonanoic acid	0.12 ± 0.03^g	1.22 ± 0.09^a	0.52 ± 0.03^f	0.93 ± 0.07^b	1.00 ± 0.02^b	0.91 ± 0.03^bc
	Hexanoic acid	ND	0.28 ± 0.05^a	ND	ND	0.16 ± 0.00^b	ND
Hydrocarbons	2,5,5-Trimethyl heptane	0.37 ± 0.05^b	0.68 ± 0.08^a	0.21 ± 0.12^c	0.48 ± 0.14^ab	0.43 ± 0.09^b	0.48 ± 0.06^ab
	2,6,10-Trimethyl dodecane	2.87 ± 0.13^a	2.82 ± 0.13^a	1.03 ± 0.08^d	2.36 ± 0.19^c	2.50 ± 0.02^bc	2.50 ± 0.06^bc
Others	Carbon dioxide	1.78 ± 0.16^a	1.79 ± 0.07^a	1.43 ± 0.13^b	1.26 ± 0.30^b	1.28 ± 0.17^b	1.30 ± 0.15^b
	2-Thioxotetrahydro-1,3-Oxazole	0.54 ± 0.11^a	0.21 ± 0.07^de	0.20 ± 0.00^e	0.26 ± 0.06^bcde	0.28 ± 0.00^bc	0.27 ± 0.05^bcd
	2-Methyl-2-nitropropane	0.68 ± 0.08^a	0.25 ± 0.05^bc	0.16 ± 0.03^e	0.20 ± 0.00^de	0.27 ± 0.00^b	0.21 ± 0.03^cd
	Dodecamethylcyclohexasiloxane	3.63 ± 0.28^a	2.37 ± 0.17^c	3.14 ± 0.20^ab	3.27 ± 0.14^a	3.00 ± 0.04^ab	3.12 ± 0.12^ab
	N,N-Dimethylformamide	0.28 ± 0.04^cd	0.22 ± 0.07^e	0.34 ± 0.05^abc	0.28 ± 0.02^cd	0.27 ± 0.00^de	0.30 ± 0.01^abc
		RC
Category	Compounds name	500 MPa/10 min	600 MPa/3 min	600 MPa/5 min	600 MPa/7 min	600 MPa/10 min
Aldehydes and Ketones	2,2-Dimethylhex-4-yn-3-one	0.74 ± 0.03^b	0.77 ± 0.03^b	0.80 ± 0.04^b	0.84 ± 0.06^b	0.90 ± 0.06^a
	6-Methyl-5-hepten-2-one	1.70 ± 0.16^bc	1.72 ± 0.13^bc	1.65 ± 0.16^bc	1.71 ± 0.10^bc	1.82 ± 0.14^bc
	3,4-Hexanedione	1.28 ± 0.09^bc	1.33 ± 0.09^bc	1.31 ± 0.13^bc	1.31 ± 0.13^bc	1.40 ± 0.06^ab
	Hex-4-yn-3-one	0.27 ± 0.07^de	0.42 ± 0.05^b	0.19 ± 0.03^f	0.34 ± 0.02^de	0.44 ± 0.10^b
	4-Methylhept-6-en-3-one	2.75 ± 0.10^c	2.37 ± 0.10^d	2.85 ± 0.11^d	2.73 ± 0.18^c	2.59 ± 0.10^bc
	2-Nonanone	0.96 ± 0.06^b	0.88 ± 0.06^b	0.81 ± 0.10^b	0.80 ± 0.10^b	0.80 ± 0.07^a
	2-Heptnone	ND	ND	ND	ND	ND
	2-Octanone	ND	ND	ND	ND	ND
Alcohols	Trans-2,3-hexanediol	2.63 ± 0.01^de	2.73 ± 0.13^de	2.68 ± 0.36^de	2.52 ± 0.18^e	2.69 ± 0.17^de
	Trans-hexane-1,2-diol	4.39 ± 0.00^bc	4.44 ± 0.12^bc	4.67 ± 0.25^b	4.39 ± 0.05^bc	4.38 ± 0.05^bc
	1,5-Hexadien-3-ol	4.01 ± 0.02^b	4.22 ± 0.06^a	4.28 ± 0.12^a	4.13 ± 0.08^ab	4.00 ± 0.10^b
	1,3-Dioxolan-2-ylmethanol	3.41 ± 0.04^de	3.67 ± 0.27^bc	3.62 ± 0.06^bc	3.50 ± 0.00^bc	3.29 ± 0.00^ef
	3,3-Dimethyl-1-Butanol	1.66 ± 0.03^bc	1.76 ± 0.09^b	1.68 ± 0.05^bc	1.54 ± 0.12^d	1.41 ± 0.01^e
	1-(Furan-2-yl)but-3-ene-1,2-diol	1.25 ± 0.04^f	1.97 ± 0.06^b	1.81 ± 0.06^c	1.79 ± 0.00^c	1.59 ± 0.00^d
	1-Butanol	2.58 ± 0.01^ef	2.71 ± 0.06^c	2.66 ± 0.06^cd	2.51 ± 0.02^fg	2.30 ± 0.00^h
	2-Nonanol	4.49 ± 0.05^bc	4.63 ± 0.00^b	4.50 ± 0.02^bc	4.55 ± 0.03^bc	4.39 ± 0.10^cd
	Phenylethyl Alcohol	2.92 ± 0.03^d	3.13 ± 0.10^a	3.05 ± 0.02^ab	2.93 ± 0.00^cd	2.74 ± 0.04^e
	2-Heptanol	2.63 ± 0.06^d	2.99 ± 0.15^a	2.84 ± 0.23^ab	2.78 ± 0.00^bc	2.59 ± 0.18^d
Esters	Ethyl Acetate	20.94 ± 0.60^b	20.77 ± 0.35^b	20.76 ± 0.38^b	21.00 ± 0.38^b	21.14 ± 0.37^b
	Vinyl Sorbate	ND	ND	ND	ND	ND
	Ethyl-2-methylbutyrate ester	3.08 ± 0.06^bc	2.78 ± 0.02^d	3.02 ± 0.06^bc	2.99 ± 0.18^bc	3.07 ± 0.05^bc
	Ethyl butyrate	5.71 ± 0.30^b	5.49 ± 0.21^b	5.61 ± 0.17^b	5.59 ± 0.20^b	5.79 ± 0.27^b
	Ethyl citrate	2.52 ± 0.00^bc	2.08 ± 0.06^f	2.23 ± 0.00^ef	2.35 ± 0.05^de	2.19 ± 0.06^f
	Hexyl isovalerate	0.29 ± 0.00^d	0.36 ± 0.07^bc	0.37 ± 0.00^bc	0.32 ± 0.00^cd	0.38 ± 0.04^bc
	Methyl 8-oxooctadecanoate	2.86 ± 0.29^bc	2.63 ± 0.10^c	2.62 ± 0.32^c	2.72 ± 0.02^bc	3.03 ± 0.03^b
	Ethyl hexanoate	3.54 ± 0.33^bc	3.43 ± 0.58^bc	3.40 ± 0.22^bc	3.58 ± 0.32^bc	3.83 ± 0.26^ab
	Ethyl propanoate	2.14 ± 0.02^bc	2.22 ± 0.13^abc	2.28 ± 0.00^abc	2.40 ± 0.01^ab	2.02 ± 0.02^c
	Hexyl acetate	4.56 ± 0.26^bc	4.00 ± 0.23^c	4.33 ± 0.21^bc	4.53 ± 0.27^bc	4.86 ± 0.27^b
Heterocyclic and aromatic compounds	2,6-Dimethylpyrazine	3.58 ± 0.15^bc	3.42 ± 0.12^c	3.33 ± 0.15^c	3.34 ± 0.23^c	3.48 ± 0.20^ab
	2,3-Dihydro Benzofuran	1.16 ± 0.12^cd	1.10 ± 0.00^cd	0.96 ± 0.06^cde	0.96 ± 0.13^cde	1.10 ± 0.12^bc
	2,6-Lutidine	0.48 ± 0.08^cd	0.41 ± 0.00^d	0.44 ± 0.00^cd	0.41 ± 0.06^d	0.35 ± 0.06^c
	2-Heptyl-1,3-dioxolane	1.66 ± 0.43^b	1.61 ± 0.31^b	1.33 ± 0.12^bcd	1.47 ± 0.25^bc	1.57 ± 0.20^ab
	Styrene	ND	ND	ND	ND	ND
Acids	Azetidine-2-carboxylic acid	0.68 ± 0.05^cd	0.95 ± 0.02^a	0.92 ± 0.09^a	0.85 ± 0.05^ab	0.75 ± 0.06^bc
	4-(Benzyloxy)-3-methoxy-2-nitrobenzoic acid	ND	ND	ND	ND	ND
	Nonanoic acid	0.81 ± 0.03^cd	0.93 ± 0.08^bc	0.81 ± 0.12^de	0.75 ± 0.00^de	0.69 ± 0.07^e
	Hexanoic acid	ND	ND	ND	ND	ND
Hydrocarbons	2,5,5-Trimethyl heptane	0.47 ± 0.11^ab	0.48 ± 0.12^ab	0.51 ± 0.11^ab	0.47 ± 0.10^ab	0.52 ± 0.12^ab
	2,6,10-Trimethyl dodecane	2.56 ± 0.19^bc	2.52 ± 0.06^bc	2.55 ± 0.06^ab	2.63 ± 0.10^ab	2.64 ± 0.09^ab
Others	Carbon dioxide	1.26 ± 0.12^b	1.29 ± 0.07^b	1.27 ± 0.19^b	1.20 ± 0.19^b	1.22 ± 0.16^b
	2-Thioxotetrahydro-1,3-Oxazole	0.31 ± 0.00^b	0.25 ± 0.00^bcde	0.23 ± 0.03^cde	0.29 ± 0.00^bc	0.31 ± 0.03^a
	2-Methyl-2-nitropropane	0.18 ± 0.00^de	0.27 ± 0.00^b	0.25 ± 0.04^bc	0.21 ± 0.00^cd	0.17 ± 0.00^cd
	Dodecamethylcyclohexasiloxane	3.21 ± 0.12^ab	2.98 ± 0.03^b	3.08 ± 0.25^ab	3.12 ± 0.11^ab	3.20 ± 0.10^ab
	N,N-Dimethylformamide	0.33 ± 0.00^abcd	0.29 ± 0.00^bcd	0.30 ± 0.05^abc	0.35 ± 0.00^ab	0.36 ± 0.01^a

Data are expressed as mean ± SD (n = 3). RC: Relative content (%), ND: Not Detectable, untreated: fermented but not pressure or thermal treated.

^a-i Different letters in the same row indicate a significant difference (p ≤ 0.05).

Table 8. Effects of thermal processing and high pressure processing on concentrations (mean ± SE, %) of different volatile compound groups in fermented pomegranate juice

Treatment	RC
	Aldehydes and Ketones	Heterocyclic and aromatic compounds	Esters	Alcohols	Acids	Hydrocarbons	Other compounds
Unfermented	25.52 ± 0.82^a	52.80 ± 1.21^a	5.10 ± 0.30^d	6.45 ± 0.93^g	0.12 ± 0.02^g	3.24 ± 0.13^ab	6.77 ± 0.47^a
Untreated	7.38 ± 1.60^b	5.45 ± 0.60^c	41.49 ± 1.20^c	35.15 ± 0.80^a	2.19 ± 0.22^a	3.5 ± 0.20^a	4.84 ± 0.40^b
65 °C/20min	5.23 ± 0.80^c	4.23 ± 0.40^d	56.34 ± 1.55^a	26.98 ± 1.00^f	0.71 ± 0.11^f	1.24 ± 0.30^c	5.27 ± 0.40^b
400 MPa/10 min	7.51 ± 0.70^b	6.74 ± 0.30^b	45.03 ± 1.46^b	31.10 ± 0.60^bc	1.51 ± 0.13^de	2.84 ± 0.30^b	5.27 ± 0.50^b
500 MPa/5 min	7.46 ± 1.10^b	6.29 ± 0.50^bc	44.27 ± 1.20^b	32.13 ± 0.60^b	1.82 ± 0.04^bc	2.93 ± 0.10^b	5.1 ± 0.20^b
500 MPa/7 min	7.59 ± 0.90^b	6.42 ± 0.50^bc	45.14 ± 1.26^b	31.04 ± 0.58^bc	1.63 ± 0.04^bcde	2.98 ± 0.10^b	5.2 ± 0.30^b
500 MPa/10 min	7.70 ± 0.60^b	6.88 ± 0.70^b	45.64 ± 1.71^b	29.97 ± 0.49^de	1.49 ± 0.25^de	3.03 ± 0.30^b	5.29 ± 0.20^b
600 MPa/3 min	7.49 ± 0.60^b	6.54 ± 0.40^bc	43.76 ± 1.55^b	32.25 ± 0.30^b	1.88 ± 0.10^b	3.00 ± 0.20^b	5.08 ± 0.10^b
600 MPa/5 min	7.61 ± 0.70^b	6.06 ± 0.30^bc	44.62 ± 1.30^b	31.79 ± 0.60^bc	1.73 ± 0.20^bcd	3.06 ± 0.10^b	5.13 ± 0.50^b
600 MPa/7 min	7.73 ± 0.80^b	6.18 ± 0.60^bc	45.58 ± 1.24^b	30.64 ± 0.40^cd	1.60 ± 0.05^cde	3.10 ± 0.20^b	5.17 ± 0.30^b
600 MPa/10 min	7.95 ± 0.50^b	6.50 ± 0.55^bc	46.31 ± 1.20^b	29.38 ± 0.60^e	1.44 ± 0.13^e	3.16 ± 0.20^ab	5.26 ± 0.20^b

Data are expressed as mean ± SD (n = 3). RC: Relative content (%). ^a-g Different letters in the same column indicate a significant difference (p ≤ 0.05). Untreated: fermented but not pressure or thermal treated.

Figure 2. Influence of different HPP and TP treatment conditions on the sensory attributes of fermented pomegranate juice