Effects of Zanthoxylum bungeanum M. and Capsicum annuum L. oil on the formation of aroma characteristics of Jiao-ma chicken as evaluated by GC-MS and E-nose

Abstract

Spices have long been used in many countries to enhance or modify the flavor of meat and meat products. In general, different cooking treatments of spices can produce significantly different flavor. Jiao-ma chicken (JMC), as a traditional and characteristic cuisine in China, is prepared by boiled chicken seasoned with its exquisite flavor sauce. The delicious flavor of its sauce has won great popularity, and fried chili pepper (Capsicum annuum L.) oil (CPO) and pricklyash peel (Zanthoxylum bungeanum M.) oil (PPO) are its essential ingredients. To investigate the effects of CPO and PPO on the formation of aroma characteristics of JMC, the volatiles of CPO and PPO with and without chicken soup (CS) were analyzed by SPME/GC-MS. A total of 69 and 64 volatiles were identified in semi-finished JMC sauce (CS, CPO, and PPO) and final JMC sauce, respectively. GC-MS results showed that the composition and proportions of volatiles were significantly changed. Adding CPO and PPO to the basic CS generated several terpenes, and caused significant decreases in alcohols, aldehydes, and ketones, resulting in an exquisite spicy flavor of JMC sauce. Combined with GC-O and principal component analysis (PCA) results, it was found that 23 volatiles positively involved in the aroma formation, and might be significantly contributed to the unique flavor of JMC sauces.

Keywords:
chili pepper; pricklyash peel; Jiao-ma chicken (JMC) sauce; volatile profiles; Principle component analysis (PCA)

1 Introduction

Jiao-ma chicken (JMC), also named pepper chicken, is a famous cuisine from Xinjiang Province, China. JMC has long been favored by consumers due to its characteristics, unique ways of eating, full-bodied chicken aroma, savor-rich properties, and long aftertaste. This cuisine needs to be cooked in two steps: boiling the chicken and making the flavory sauce. The flavory sauce is generally prepared by addition of the fried spice oils to the boiled chicken soup (CS). Plus prior to tasting this dish, consumers need to immerse the chicken meat into the flavory sauce. Thus, this dish can not only preserve the flavor of chicken but also incorporate the flavor of the spices. When tasting it at first time, consumers are often amazed by its exquisite taste and aroma attributes, mixed with the flavor of “ma”, “la” and “umami”, and the characteristic aroma of spice oil and chicken. Among these, “ma” and “la” are the feeling of tingling and hot in the mouth and nose. The “ma” effect is generated from a spice, called “huajiao,” and the “la” taste is from red chili. Furthermore, the addition of these two spice oils can intensify the meat flavor of chicken to some extents, and make the consumers salivating. Thus, these two ingredients might function prominently in the formation of the characteristic flavor of JMC.

Spices, regarded as “plant products”, are often used for seasoning, flavoring, and imparting aroma in foods (Garruti et al., 2021; Dhanya & Sasikumar, 2010), and can enhance and/or modify the flavory properties of food in cooking (Raghavan, 2006). Spices are used in many countries to improve the flavor of meat/meat products (Wang et al., 2022). As the key spices used in JMC, “Huajiao,” also named pricklyash peel, is the dried fruit of Zanthoxylum bungeanum Maxim. from the aromatic Rutaceae family (Yang, 2008), whereas chili pepper (Capsicum annuum L.) belongs to the Solanaceae family (Kumar et al., 2014). This combination of two spices is extensively used for cooking in many parts of the world, especially popular in Sichuan Province, China.

Abundant information on the volatile analysis of spices and their effects on meat flavor are available (Yang, 2008; Pino et al., 2006; Lee et al., 2005). Moreover, researchers found that the unique or characteristic flavors of spices can be changed, intensified or integrated into a particularly attractive aroma by certain cooking technique, such as heated in the meat soup or fried in vegetable oil at high temperature. For example, Ho et al. (1989) showed that baking or deep-frying shallots could increase the amounts of dimethyl thiophene, unsaturated alkyl trisulfides, and some small high molecular weight compounds. Chen et al. (2017) found that besides the strong tingling taste of dried pricklyash, deep-frying spices can also generate a moderate salty flavor, which is more adaptable for the demand of Chinese cuisine. To our knowledge, few study has been made on the effects of fried chili pepper and pricklyash peel oil on the formation of aroma characteristics of meat in literature.

Current study aims to (1) investigate the volatile compounds of JMC sauces, and (b) evaluate the impacts of different fried spicy oils on the formation of aroma characteristics of JCPs by GC-MS, GC-O and E-nose.

2 Materials and methods

2.1 Materials

Fresh chicken, approximately 60 days of age, were purchased from Aijia Supermarket, Shihezi (Xinjiang, China), and stored at -18 °C until analysis. Chinese traditional spices (e.g., ginger, scallion, dried chili pepper, and green pricklyash peel) and other condiments (salt) were obtained from local wholesalers or local markets.

The standard solution containing a series of n-alkanes (C₆–C₂₆) was provided by Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). 1,2-Dichlorobenzene, which was used as the internal standard, was obtained from Sigma Chemical, Co. (St. Louis, Mo, USA).

2.2 Sample preparation

Preparation of chili pepper oil (CPO) and pricklyash peel oil (PPO)

These two spices were placed in a frying pan with pre-heated rapeseed oil (approximately 100.0 mL), then heated at 150 °C for approximately 3 and 5 min to obtain the CPO and PPO samples, respectively. In this process, the mixture was constantly stirred to prevent local overheating. Thereafter, the samples were cooled down to the room temperature, sealed in a flask and maintained 24 h, then remove granules prior to further analyzing. These obtained samples were denoted as the basic elements of JMC sauce, namely, CPO and PPO.

Preparation of JMC sauce samples

Fresh chicken carcass, approximately 0.8 kg each, were washed with running water for several times, then placed in boiling water, and boiled for another 50 min. The chicken carcass was then removed, and the obtained samples was known as chicken soup (CS). Subsequently, the previously prepared CPO or PPO were added to the CS samples, respectively, and the mixture was maintained the temperature with slightly boiling state for 20 min. The solutions were diluted to 1 L, and these two obtained samples were named JMC1 and JMC2. JMC3 was the JMC sample with CPO and PPO and added with 0.5% salt. All the JMCs were immediately cooled and stored at 4 °C for 24 h for further analysis.

2.3 GC-MS analysis

The homogenized JMC sauce sample (5.0 mL) was quantified into a 15-mL vial with a magnetic stirring bar, to which 4 μL internal standard (1,2-dichlorobenzene) in methanol (0.555 μg/μL) was added as well. Afterwards, the vial was sealed with PTFE/BYTL septum, and then placed in a water bath at 50 °C to equilibrate the headspace. The fiber (75 µm CAR/PDMS) (Supelco, USA) was then exposed to the headspace and maintained for 30 min. Subsequently, the fiber was immediately transferred to the GC injection port for thermal desorption (7 min at 250 °C). The selection of desorption time and desorption temperature (250 °C) were based on the principle of improving the peak shape and sensitivity while reducing the carryover from the previous analysis.

Volatile compounds were separated by a DB-5 capillary column (30 m × 0.25 mm × 0.25 μm) and analyzed with a Finnigan Trace GC-MS (Finnigan, USA). The flow rate of carrier gas (helium) was 0.9 mL/min. Oven temperature was held at 40 °C for 3 min, then ramped to 90 °C at 6 °C/min, and finally increased to 210 °C at 10 °C/min and kept at this temperature for 3 min. MS in the electron impact ionization mode were captured in a mass range of m/z 35-450 at 70 eV.

Volatiles identification was based on comparison of (a) the Kováts retention indices (KI) with those of authentic standard compounds or those of reported in the literature. KI was determined for each volatile with a series of n-alkanes (C₆–C₂₆) according to the method of our previous research (Tian et al., 2017); (b) the mass spectra with those in the Wiley and NIST Library (Rahman et al., 2022).

2.4 GC-O analysis

GC-O was carried out using an Finnigan trace GC (Finnigan, USA) equipped with an FID and an OP275 sniffing port (GL Sciences Inc., Japan). The samples collected, column, and operating conditions were all the same as those of the GC-MS analysis, and the detection frequency method used in GC-O analysis was conducted according to our previous research (Zhan et al., 2013).

2.5 E-nose analysis

E-nose analysis was performed with an electronic nose (Fox 4000 gas-sensor, Alpha M.O.S., Toulouse, France, containing 18 metal oxide sensors) to quantify the sensor responses for the volatiles of JMC samples, according to previous study (Zhang et al., 2022).

The E-nose analysis was conducted according to our previous research (Tian et al., 2014). Prior to detection, each homogenized JMC sauces (2.0 g) was placed in a 10 mL glass vial, and then sealed with preheated Teflon/Silicon septa and screw capped. The samples were equilibrated at 60 °C for 5 min. Sensor-response data were acquired for 120 s. The vessel was purged with compressed air for 3 min before the next run. All JMC sauces were analyzed with three replicates. In order to simplify the data analyzing, only the maximum resistance changes of each sensor were collected.

2.6 Statistical analysis

The obtained results were subjected to the Analysis of Variance (ANOVA) and analyzed through Duncan’s multiple comparison tests. Differences among samples in terms of volatile compounds were found a 95% significant difference (p < 0.05) by SPSS version 20.0. For purpose of providing a solid evidence of correlations among different JMC sauces prepared with different CPO and PPO ratio, a principal component analysis (PCA) was performed by Unscrambler established by the volatile compounds found in GC-MS-O.

3 Results and discussion

3.1 Compound analysis of semi-finished JMC products

Table 1 shows the volatile compounds found from semi-finished products of JMC sauce (CS, CPO and PPO). A total of 69 volatiles were observed in the GC-MS profiles, including 8 esters, 16 alcohols, 4 aldehydes, 4 ketones, 29 alkenes and terpenes, 2 sulfur compounds and 6 others.

Table 1
Volatile compounds identified in basic materials of JMC sample.

No.	Compounds	Relative concentration (μg/100 mL)
		Chicken soup	Chili pepper oil (CPO)	Pricklyash peel oil (PPO)
1	Ethyl acetate	-	-	0.110 ± 0.10
2	Ethyl methylcarbamate	-	-	0.224 ± 0.02
3	(Z)-sabinene hydrate	-	-	1.062 ± 0.14
4	Linalyl butyrate	6.547 ± 0.56	-	-
5	Linalyl anthranilate	-	8.723 ± 1.654	3.225 ± 0.29
6	(E)-bornyl acetate	-	-	0.445 ± 0.11
7	Octyl acetate	-	-	0.427 ± 0.04
8	Geranyl acetate	0.045 ± 0.01	-	-
9	Ethanol	1.564 ± 0.05	13.018 ± 1.92	6.542 ± 0.60
10	Hexanol	0.083 ± 0.01	-	0.718 ± 0.05
11	1-Octen-3-ol	0.309 ± 0.02	-	0.511 ± 0.04
12	Heptanol	-	-	0.402 ± 0.01
13	(Z)-β-terpineol	0.183 ± 0.01	2.576 ± 0.54	2.706 ± 0.31
14	Linalool	7.908 ± 2.58	15.004 ± 1.19	20.065 ± 2.94
15	Cycloheptanol	-	-	0.309 ± 0.04
16	Octanol	-	-	0.687 ± 0.04
17	l-Terpinen-4-ol	2.319 ± 0.24	67.569 ± 6.70	11.522 ± 1.51
18	2-Furanmethanol	-	-	0.227 ± 0.09
19	α-Terpineol	-	37.973 ± 4.64	-
20	3,7-Dimethyloct-2-en-1-ol	-	-	0.216 ± 0.03
21	2,6-Octadien-1-ol	-	-	0.116 ± 0.03
22	Geraniol	0.062 ± 0.05	-	-
23	(2Z,6E)-Farnesol	0.120 ± 0.11	-	-
24	(Z)-Carveol	-	-	0.230±0.03
25	Hexanal	1.297 ± 0.26	0.730 ± 0.08	-
26	(E)-2-Heptenal	-	-	0.266 ± 0.06
27	3,7-Dimethyl-6-octenal	-	-	0.335 ± 0.02
28	(E,E)-2,4-Decadienal	2.851 ± 1.02	--	0.399 ± 0.02
29	2-Octanone	0.092 ± 0.07	-	0.210 ± 0.03
30	4-Isopropylcyclohexanone	0.043 ± 0.04	-	1.159 ± 0.18
31	Cryptone	-	5.943 ± 0.79	1.414 ± 0.16
32	Piperitone	-	17.735 ± 2.23	3.202 ± 0.56
33	3-Thujene	0.276 ± 0.05	-	11.827 ± 2.78
34	α-Pinene	-	15.464 ± 1.36	-
35	β-Pinene	0.349 ± 0.07	6.291 ± 0.70	0.258 ± 0.02
36	Sabinene	-	36.054 ± 3.43	5.706 ± 0.56
37	2-Carene	0.355 ± 0.06	65.778 ± 7.92	6.072 ± 0.86
38	β-Thujene	0.112 ± 0.115	164.336 ± 13.08	-
39	3-Carene	-	8.303 ± 1.20	-
40	α-Phellandrene	0.273 ± 0.32	45.937 ± 4.69	3.388 ± 0.36
41	α-Terpinene	0.271 ± 0.07	29.995 ± 3.61	3.527 ± 0.62
42	Myrcene	-	15.461 ± 2.01	20.170 ± 2.43
43	d-Limonene	1.752 ± 0.32	198.598 ± 25.70	35.273 ± 3.72
44	4-Carene	-	18.327 ± 1.81	-
45	β-Phellandrene	0.398 ± 0.02	-	23.390 ± 3.11
46	β-Terpinene	-	21.725 ± 2.08	-
47	γ-Terpinene	0.620 ± 0.10	84.158 ± 7.66	2.141 ± 0.30
48	(Z)-β-ocimene	0.283 ± 0.05	36.439 ± 5.10	7.472 ± 0.93
49	(E)-β-ocimene	0.264 ± 0.06	76.167 ± 8.31	15.349 ± 2.13
50	g-Terpinene	-	-	16.100 ± 1.75
51	Terpinolene	0.236 ± 0.07	13.164 ± 2.22	5.902 ± 1.02
52	(4E,6Z)-allo-ocimene	-	12.162 ± 1.86	1.804 ± 0.17
53	Perillene	-	-	0.432 ± 0.10
54	(E,E)-cosmene	-	-	0.082 ± 0.06
55	p-Cymenene	-	-	0.308 ± 0.08
56	α-Copaene	-	-	0.133 ± 0.11
57	β-Elemene	-	-	1.413 ± 0.52
58	β-Caryophyllene	0.079 ± 0.04	-	1.207 ± 0.11
59	Tricyclene	-	-	2.105 ± 0.24
60	2,6-Dimethyl-2,6-octadiene	-	-	0.635 ± 0.07
61	o-Xylene	-	-	0.142 ± 0.04
62	1,8-Cineole	0.714 ± 0.50	69.386 ± 8.98	15.209 ± 1.26
63	p-Cymene	-	11.437 ± 3.82	0.340 ± 0.11
64	m-Cymene	0.174 ± 0.04	-	-
65	o-Cymene	-	20.545 ± 3.29	3.509 ± 0.46
66	Ethyl maltol	-	-	2.836 ± 0.19
67	Dipropyl disulfide	1.527 ± 0.07	-	0.720 ± 0.27
68	(Z)-linalool oxide	0.135 ± 0.01	-	-
69	2-Methyl-3-furanthiol	9.023 ± 0.39

Among these compounds, terpenes were the largest category, and there are mainly monoterpenes (C₁₀) and sesquiterpenes (C₁₅) in this category. These compounds, comprising two and three isoprene units, are often regarded to be among the most important flavory compounds for spices (Díaz-Maroto et al., 2002). In general, they are described as green, wood, herb, turpentine, or other sensory characteristics when in the low concentrations. As shown in Table 1, 15 terpenes were detected in the CS, whereas 20 and 27 terpenes were found in CPO and PPO, respectively. Moreover, the total terpene content in CPO was 949.727 μg/100 mL, much higher than that in CS (6.156 μg/100 mL) and in PPO (183.885 μg/100 mL). D-limonene, which is related to the citrus-like and refreshing aroma, was found to be one of the most abundant terpenes in above samples. In terms of quantity, myrcene, β-thujene, γ-terpinene, (E)-β-ocimene, 2-carene, α-phellandrene, sabinene, (Z)-β-ocimene, and α-terpinene were found sufficient in the CPO, most of them have been reported to be significant for the aroma characteristics of pepper (Jirovetz et al., 2002). Meanwhile, the content of some terpenes in PPO was found much more than it was in CPO, there were mainly including β-phellandrene (23.390 μg/100 mL), myrcene (20.170 μg/100 mL), g-terpinene (16.100 μg/100 mL), and 3-thujene (11.827 μg/100 mL). These compounds were mostly monoterpenes, and might be important in the characteristic aroma of pricklyash peel. In accordance with it, Yang (2008) reported that limonene and myrcene could be the major characteristic volatile compounds for Huajiao. Additionally, Jiang & Kubota (2004) also found that limonene and β-phellandrene were the major components for the Zanthoxylum piperitum (pricklyash peel) oil.

In term of alcohols, another big class but less than the content of terpenes, there were 8, 5, and 12 types of alcohols been found in CS, CPO, and PPO, respectively. The unsaturated alcohol, 1-octen-3-ol, is produced by lipid oxidation and degradation (Tian et al., 2014) and often refers to the mushroom, green, and earthy aroma; it was only detected in the CS sample (0.309 μg/100 mL), but not in the other two samples. This compound usually shows strong modification to meat flavors, and is one of the most prominent aromatic contributors to chicken. In addition, a large number of terpene alcohols were also found in the above samples. For example, linalool and 1,8-cineole are found in all three samples. α-terpineol was only found in the CPO, and in a relatively high content (37.973 μg/100 mL). 1,8-Cineole relates to the peppermint-like flavor, and linalool has a floral aroma when at low threshold (Jagella & Grosch, 1999). These two compounds were found in many types of spices as the characteristic volatile compounds.

As for aldehydes, only four were identified in three samples. Furthermore, they all existed at relatively low concentrations. Among them, hexanal (1.297 μg/100 mL) and (E,E)-2,4-decadienal (2.851 μg/100 mL) were presented at higher levels in CS compared to the other two samples (CPO and PPO). These two aldehydes have relatively low thresholds, which is at 0.007 μg/100 g for hexanal and 0.45 μg/100 g for (E,E)-2,4-decadienal. They are also reported as the key volatile compounds for chicken flavor (Grosch, 1993).

3.2 Compound analysis of JMC sauces

To investigate the changes of volatiles during making the JMC sauce, the CS added with CPO (JMC1), PPO (JMC2), and CPO:PPO at 1:1 v:v (JMC3) were analyzed and compared, and the CS was used as the control. Table 2 lists the specific concentrations of the compounds, unknown compounds and alkanes were excepted.

Table 2
Volatile compounds of different JMC sauce samples, measured by GC-MS analysis.

No.	Compounds		KI		CAS No.	Relative concentration (μg/100 mL)				Odor description
			KIcal	KIref		CS	JMC1	JMC2	JMC3
1	Ethyl acetate	P1	892	878	000141-78-6	0.000 ± 0.00a	0.000 ± 0.00a	0.000 ± 0.00a	4.598 ± 0.32b	Fruity, flower
2	Ethyl butyrate		1013	1021	000105-54-4	0.000 ± 0.00a	0.000 ± 0.00a	0.120 ± 0.02b	0.000 ± 0.00a
3	Ethyl valerate		1119	1116	000539-82-2	0.000 ± 0.00a	0.000 ± 0.00a	0.130 ± 0.01b	0.000 ± 0.00a
4	Ethyl heptanoate		1303	1310	000106-30-9	0.000 ± 0.00a	0.000 ± 0.00a	0.280 ± 0.03b	0.000 ± 0.00a
5	Isobutyl hexanoate		1350	1356	000105-79-3	0.000 ± 0.00a	0.000 ± 0.00a	0.142 ± 0.02b	0.000 ± 0.00a
6	Ethyl octanoate		1431	1420	000106-32-1	0.000 ± 0.00a	0.000 ± 0.00a	0.218 ± 0.03b	0.000 ± 0.00a
7	Linalyl butyrate		1492	-	000078-36-4	6.547 ± 0.56b	0.000 ± 0.00a	0.000 ± 0.00a	0.000 ± 0.00a
8	Linalyl anthranilate	P2	1506	-	007149-26-0	0.000 ± 0.00a	5.478 ± 0.52b	6.272 ± 0.30b	16.925 ± 3.68c	Green, salty, flower
9	Linalool propionate		1673	1690	000144-39-8	0.000 ± 0.00a	0.000 ± 0.00a	5.970 ± 1.159b	0.000 ± 0.00a
10	Geranyl acetate		1728	1740	000105-87-3	0.045 ± 0.01b	0.081 ± 0.01c	0.000 ± 0.00a	0.000 ± 0.00a
11	Ethanol	P3	906	900	000064-17-5	1.564 ± 0.05a	5.594 ± 0.14a	4.197 ± 0.04 a	3.704 ± 0.29b	Flower, sweet
12	2-Methyl-1-propanol		1072	1086	000078-83-1	0.000 ± 0.00a	0.000 ± 0.00a	0.123 ± 0.01b	0.000 ± 0.00a
13	Hexanol		1363	1360	000111-27-3	0.083 ± 0.01b	0.341 ± 0.06c	0.144 ± 0.01b	0.000 ± 0.00a
14	1-Octen-3-ol	P4	1418	1430	003391-86-4	0.309 ± 0.02d	0.278 ± 0.02c	0.000 ± 0.00a	0.202 ± 0.01b	Mushroom
15	(Z)-β-terpineol	P5	1492	-	007299-41-4	0.183 ± 0.01a	0.526 ± 0.07b	0.142 ± 0.01a	0.800 ± 0.04c	Must
16	Linalool	P6	1532	1547	000078-70-6	7.908 ± 2.58a	10.797 ± 1.78a	30.347 ± 1.01b	49.348 ± 6.77c	Flower, lavender
17	(Z)-p-Menth-2-en-2-ol		1592	1615	029803-82-5	0.000 ± 0.00a	0.000 ± 0.00a	0.426 ± 0.19b	0.000 ± 0.00a
18	l-Terpinen-4-ol	P7	1632	-	020126-76-5	2.319 ± 0.24a	2.445 ± 0.05a	6.101 ± 0.41b	6.487 ± 0.47b	Herb, spicy
19	4- Isopropylcyclohexanol		1659	-	004621-04-9	0.000 ± 0.00a	0.000 ± 0.00a	0.288 ± 0.04b	0.000 ± 0.00a
20	a-Terpineol	P8	1713	1698	000098-55-5	0.000 ± 0.00a	1.126 ± 0.20b	1.652 ± 0.32b	5.805 ± 0.68c	Fresh, flower, sweet
21	Geraniol		1811	1830	000106-24-1	0.062 ± 0.05b	0.000 ± 0.00a	0.000 ± 0.00a	0.000 ± 0.00a
22	(2Z,6E)-farnesol		2206	2286	003790-71-4	0.120 ± 0.11b	0.000 ± 0.00a	0.000 ± 0.00a	0.000 ± 0.00a
23	Hexanal	P9	1061	1080	000066-25-1	1.297 ± 0.26b	0.107 ± 0.06a	0.000 ± 0.00a	1.894 ± 0.54c	Grass, tallow, fat
24	(Z)-2-heptenal		1301	1319	057266-86-1	0.000 ± 0.00a	0.000 ± 0.00a	0.000 ± 0.00a	1.700 ± 0.19b
25	Geranial	P10	1751	1733	000141-27-5	0.000 ± 0.00a	0.000 ± 0.00a	0.000 ± 0.00a	2.384 ± 0.69b
26	4-Isopropylbenzaldehyde		1778	1769	000122-03-2	0.000 ± 0.00a	0.120 ± 0.10b	0.000 ± 0.00a	0.000 ± 0.00a
27	(E,E)-2,4-decadienal	P11	1791	1784	025152-84-5	2.851 ± 1.02	0.000 ± 0.00a	0.000 ± 0.00a	0.000 ± 0.00a	Fatty, oily, meaty
28	2-Octanone		1270	1283	000111-13-7	0.092 ± 0.07b	0.000 ± 0.00a	0.000 ± 0.00a	0.000 ± 0.00a
29	3-Thujanone	P12	1362	-	001125-12-8	0.000 ± 0.00a	0.000 ± 0.00a	5.324 ± 0.70c	1.217 ± 0.16b	Pepper, green
30	β-Thujone		1441	-	000471-15-8	0.000 ± 0.00a	0.000 ± 0.00a	0.100 ± 0.09b	0.000 ± 0.00a
31	a-Thujone		1456	-	000546-80-5	0.000 ± 0.00a	0.000 ± 0.00a	0.189 ± 0.13b	0.000 ± 0.00a
32	4-Isopropylcyclohexanone		1473	-	005432-85-9	0.043 ± 0.04b	0.000 ± 0.00a	0.000 ± 0.00a	0.000 ± 0.00a
33	3-Thujene	P13	938	924	002867-05-2	0.276 ± 0.05a	2.068 ± 0.34c	0.804 ± 0.15b	5.405 ± 0.27d	Green, herb
34	α-Pinene	P14	998	1026	000080-56-8	0.000 ± 0.00a	3.837 ± 0.46b	0.000 ± 0.00a	4.209 ± 0.41b	Lemon
35	Camphene	P15	1031	1059	000079-92-5	0.000 ± 0.00a	0.081 ± 0.08a	0.000 ± 0.00a	1.495 ± 0.16b	Camphor
36	β-Pinene	P16	1069	1094	000127-91-3	0.349 ± 0.07a	5.02 ± 0.41b	0.038 ± 0.06a	4.748 ± 0.61b	Pine, resin, turpentine
37	Sabinene	P17	1081	1103	003387-41-5	0.000 ± 0.00a	1.670 ± 0.10b	0.000 ± 0.00a	11.480 ± 1.69b	Pepper, turpentine, wood
38	2-Carene	P18	1107	1122	000554-61-0	0.355 ± 0.06b	0.409 ± 0.10a	0.870 ± 0.16a	19.352 ± 2.88b	Lemon, resin
39	β-Thujene	P19	1117	1133	028634-89-1	0.112 ± 0.115a	69.205 ± 17.60b	0.000 ± 0.00a	81.456 ± 12.32b	Wood, green, herb
40	3-Carene		1139	-	000498-15-7	0.000 ± 0.00a	0.176 ± 0.11a	0.000 ± 0.00a	1.162 ± 0.22b
41	α-Phellandrene	P20	1146	1157	000099-83-2	0.273 ± 0.32a	16.602 ± 2.88b	0.666 ± 0.12a	3.074 ± 0.88a	Sweet, fruit, herb
42	α-Terpinene		1162	1167	000099-86-5	0.271 ± 0.07b	0.000 ± 0.00a	0.000 ± 0.00a	0.000 ± 0.00a
43	Myrcene	P21	1173	1170	000123-35-3	0.000 ± 0.00a	8.015 ± 0.17c	2.676 ± 0.18b	15.740 ± 0.63d	Balsamic, must, spice
44	d-Limonene	P22	1186	-	005989-27-5	1.752 ± 0.32a	17.581 ± 2.57b	8.029 ± 1.89ab	53.120 ± 7.08c	Citrus, mint
45	4-Carene		1191	1149	029050-33-7	0.000 ± 0.00a	0.511 ± 0.11b	0.000 ± 0.00a	3.262 ± 0.38c
46	β-Phellandrene	P23	1224	1203	000555-10-2	0.398 ± 0.02a	2.642 ± 0.11b	6.584 ± 0.43c	10.440 ± 1.43d	Fresh, orange, spice
47	β-Terpinene		1238	1218	000099-84-3	0.000 ± 0.00a	3.446 ± 0.37b	0.000 ± 0.00a	0.000 ± 0.00a
48	γ-Terpinene	P24	1251	1232	000099-85-4	0.620 ± 0.10a	2.667 ± 0.25c	1.876 ± 0.23b	5.154 ± 0.43d	Gasoline, turpentine
49	(Z)-β-ocimene		1259	1236	003338-55-4	0.283 ± 0.05a	2.315 ± 0.22c	1.145 ± 0.17b	5.016 ± 0.43d
50	(E)-β-ocimene	P25	1262	1244	003779-61-1	0.264 ± 0.06a	2.121 ± 0.23b	3.401 ± 0.29c	5.681 ± 0.62d	Sweet, herb
51	Terpinolene		1274	1271	000586-62-9	0.236 ± 0.07a	0.852 ± 0.09b	0.784 ± 0.08b	1.787 ± 0.17c
52	(4E,6Z)-2,6-dimethyl-2,4,6-octatriene		1387	-	007216-56-0	0.000 ± 0.00a	0.393 ± 0.06c	0.078 ± 0.04b	0.000 ± 0.00a
53	β-Caryophyllene		1552	1570	000087-44-5	0.079 ± 0.04b	0.000 ± 0.00a	0.000 ± 0.00a	0.000 ± 0.00a
54	Estragole		1723	1679	000140-67-0	0.000 ± 0.00a	0.312 ± 0.06b	0.000 ± 0.00a	0.000 ± 0.00a
55	Pentadecane		1423	-	000629-62-9	0.111 ± 0.09b	0.000 ± 0.00a	0.000 ± 0.00a	0.000 ± 0.00a
56	1,8-Cineole	P26	1181	1199	000470-82-6	0.714 ± 0.50a	17.571 ± 2.54c	3.429 ± 0.47a	12.788 ± 1.64b	Mint, sweet
57	p-Cymene		1239	1253	000099-87-6	0.000 ± 0.00a	2.611 ± 0.56c	0.739 ± 0.13b	3.050 ± 0.18c
58	m-Cymene		1267	1263	000535-77-3	0.174 ± 0.04b	0.000 ± 0.00a	0.000 ± 0.00a	0.000 ± 0.00a
59	o-Cymene		1276	1298	000527-84-4	0.000 ± 0.00a	0.463 ± 0.07b	0.000 ± 0.00a	0.000 ± 0.00a
60	(Z)-1,1,3,5-trtramethyl-cyclohexane		1301	-	050876-32-9	0.000 ± 0.00a	0.000 ± 0.00a	0.195 ± 0.05b	0.000 ± 0.00a
61	Dipropyl disulfide	P27	1362	1378	000629-19-6	1.527 ± 0.07b	1.785 ± 0.15c	0.000 ± 0.00a	0.000 ± 0.00a	Garlic, pungent
62	(Z)-linalool oxide		1437	1451	005989-33-3	0.135 ± 0.01b	0.000 ± 0.00a	0.156 ± 0.02b	2.005 ± 0.11c
63	Anethol	P28	1836	1817	000104-46-1	0.000 ± 0.00a	2.118 ± 0.30b	0.000 ± 0.00a	13.911 ± 1.18c	Anise, spicy
64	Eugenol	P29	2119	2153	000097-53-0	0.000 ± 0.00a	6.733 ± 1.24c	2.248 ± 0.28b	1.418 ± 0.30b	Clove, honey

• KI_cal: Kováts retention indices calculated of unknown compounds on a DB-WAX capillary column (30 m × 0.25 mm × 0.25 μm) with a homologous series of n-alkanes (C₆-C₂₆). KI_ref: Kováts retention indices obtained from the species database (National Institute of Standards and Technology, 2022) or in the literature. ^a-d Numbers with different letters are significantly different from one another in each row (p < 0.05). P1-P29 were the compounds corresponding to Figure 1. CAS No.: The numbers from Chemical Abstracts Service (CAS). KI: Kováts index. CS: Control samples.

As shown in Table 2, a total of 32, 37, 36, and 34 volatile compounds were identified in CS and JMC1–JMC3 samples, respectively. Table 2 groups compounds on the basis of their functionality. For the individual JMC samples, the volatiles, including 2 esters (6.592 μg/100 mL), 8 alcohols (12.548 μg/100 mL), 2 aldehydes (4.148 μg/100 mL), 15 terpenes (6.262 μg/100 mL), and 2 other compounds (1.662 μg/100 mL) existed in the control sample CS. Volatiles in JMC1 contained 2 esters (5.559 μg/100 mL), 7 alcohols (21.107 μg/100 mL), 2 aldehydes (0.227 μg/100 mL), 23 terpenes (160.568 μg/100 mL), and 3 other compounds (10.636 μg/100 mL); Volatiles in JMC2 contained 7 esters (13.132 μg/100 mL), 9 alcohols (43.420 μg/100 mL), 15 terpenes (31.314 μg/100 mL), and 2 other compounds (2.404 μg/100 mL); Moreover, 2 esters (21.523 μg/100 mL), 6 alcohols (66.346 μg/100 mL), 3 aldehydes (5.978 μg/100 mL), 19 terpenes (248.419 μg/100 mL), and 3 other compounds (17.334 μg/100 mL) were identified in JMC3. Detailed information of the main volatiles in JCP samples are presented in the following section.

Terpenes were found closely related to the spicy and herbal attributes. In current study, they were found to be the largest class of volatile compounds for JMC sauce. The results from control sample showed that 15 types of terpenes were identified. Based on our study, these terpenes were not related to the volatile compounds from chicken, so they probably derived from the condiments of CS, like ginger and scallion, ect. The results from JMC1-JMC3 analyzing showed that 11, 4, and 7 new types of terpenes were detected in JMC1, JMC2 and JMC3 respectively. 5 (α-pinene, camphene, sabinene, 3-carene, and 4-careneoriginated) in 7 terpenes from JMC3 were proved originally from CPO, and myrcene, p-cymene were from CPO and PPO. However, compared with the results from raw material analyzing (CPO and PPO), the type of most terpenes were the same as it has been found in the raw materials, and they can be existed even after being added to the CS. In this experiment, only camphene was a new-discovered terpene found in JMC1 and JMC3. It was also found that the terpene contents were significantly decreased in JMC1 and JMC2 (160.568 μg/100 mL and 31.314 μg/100 mL), but increased in JMC3 (248.419μg/100mL). For example, β-thujene, described as a woody, green and herbal note, was found at a high concentration of 164.336 μg/100 mLin CPO, but at relatively lower concentrations (69.205-81.456 μg/100 mL) in JMC1 and JMC3, plus this compound was undetected in JMC2. D-limonene, as the main contributor to the spicy flavor, exhibited a similar condition to β-thujene, the terpene contents were significantly decreased (p < 0.05) in JMC1-5. Meanwhile, some terpenes, such as α-terpinene, (2-, 3-, and 4-) careens, and o-cymene, were either undetected or at the trace level in JMC1-5. These findings indicated that terpene compounds from chili pepper and pricklyash might be inhibited by or interacted with chicken volatiles, thus resulted in different content levels among samples. Despite the significant decrease of terpenes from the semi-finished products to the final products, JMC3 exhibited a coordinated overall flavor, such as generous salty flavor and mild tingling flavor. This result showed that only small amount of terpene in samples can present an appropriate sensory effect, it is due to the low threshold value of terpene. This finding is in accordance with several published studies, they also agreed with that terpene compounds might have significant effects on food’s aromas, even in the micro concentrations (Marais, 2017).

Other terpenoids, including monoterpene alcohols, aldehydes, and ketones, were found as the second largest volatile class for the aroma compound analyzing of JMC sauce. These compounds were reported to be either generated directly, or converted from sesquiterpenes and monoterpenes originally from fresh spices by oxidation, dehydrogenation, and other reactions. In this study, JMC3 owned all highest volatile compound levels except for (Z)-p-menth-2-en-2-ol, 3-thujanone, and a-/β-thujone. However, compared with the results from volatile compound analyzing of semi-finished JMCs (CPO and PPO), the terpenoids from final JMCs presented a similar change tendency to the other volatiles, like terpenes. In brief, the amount of terpenoids was significantly decreased during processing into the final product.

Similar to our results, esters were found to have weak odor influence on meat products (Li et al., 2016). Table 2 shows the only two types of esters were detected in the control and JMC3 samples, but the total concertration of esters was found at 21.523 μg/100 mL in JMC3, which was much higher than it in the CS (6.592 μg/100 mL); especially for the compound of linalyl anthranilate, as high as 16.925 μg/100mL was found in JMC3, and it was also detected in high content for JMC1 and JMC2. Thus, most of esters might be derived from spices (chili pepper and pricklyash), and only small amount was produced from lipid oxidation of monoterpene alcohols and acetic acid (Li et al., 2016). This results was similar to our previous findings, which is the amount of monoterpene alcohols was decreased significantly during cooking process..

Dipropyl disulfide was the only one S-containing compound detected in both control and JMC1 samples. The formation of this compound is associated with S-containing amino acids, namely, cysteine and methionine degradation (Varlet & Fernandez, 2010). Other compounds, such as alcohols, aldehydes, and ketones, were found either at trace amounts or not detected. This finding was in accordance with the study of Jung et al. (2014), who found that some aldehydes (such as 2-methyl-butanal and 3-methyl-butanal) and sulfur compounds are inhibited when nutmeg is added.

3.3 E-nose analysis

We used the E-nose to differentiate the control sample CS and JMC1-JMC3 in order to confirm the results obtained from the GC-MS-O equiped with the PCA model. The score plot for the first two PCs (PC1 vs PC2) is shown in Figure 1. As shown, the control sample CS was located on the upper loading plot. JMC1, prepared with CS and PPO, was on central loading plot; JMC2 was prepared with CS and CPO, locating in the left middle of the loading plot. However, JCM3 was prepared with CS and CPO:PPO in 1:1 ratio, they were gathered at the left bottom of the loading plot. These results indicated that the volatile constituents of JCM1-JCM3 differed significantly when prepared with different recipes.

Figure 1
The plot of the first two principal components based on the electronic nose data.

3.4 Principal component analysis (PCA)

For determining the contributions of these volatile compounds on the aroma profiles of JMC sauces, it is considerably important to select the most distinguishing compounds from these 64 compounds to represent the JMC aroma characteristics. Based on the results, some volatiles might have no contribution to the aroma characteristics of JMC sauce, it may because the concentration of a compound does not necessarily reflect its aroma intensity due to their different odor thresholds. Furthermore, one volatile compound hardly represents an authentic food flavor. These volatile compounds should first be odor-active, so that they can be selected codor-active, so that they can be selected as the specific characteristic compounds; this can be accomplished by the GC-O assessment (the detection frequency >50%). On the basis of the detection frequency method, 29 compounds were selected as the specific characteristic compounds. These compounds were then used in PCA to study the potential correlations between different JMC sauces undertaken various preparation processes.

Figure 2 presents the PCA results of JMC sauces followed different recipes. PC1 and PC2 accounted for 47.839% and 17.067%, respectively, of the Y variance, so the PC1 and PC2 were explored. Figure 2 shows that data from the JMC 1 (prepared with CS and CPO) and the JMC2 (prepared with CS and PPO) were on the negative axis of PC1, but they clustered in the different domains. The data from control sample CS was located between JMC1 and JMC2. However, JMC3 (prepared with CS, CPO and PPO) appeared on the positive axis of PC1. These results also indicated that the concentrations of volatiles varied in JMC1-3, it means that they had kept changing in concentrations during cooking processes. The changes of volatile concentration may be caused by the reactions between compounds from different sources (e.g.,spices, chicken and new compounds). The differences of volatile concentrations could be because of the different spices been used. In the PCA, JMC3 was negative to the other samples, but it was the most closely associated with volatile compounds except for 1-octen-3-ol, geranial, (E,E)-2,4-decadienal, β-thujene, (E)-β-ocimene, and dipropyl disulfide. These results indicated that another 23 volatile compounds might be the characteristic volatile compounds for JMC sauce.

Figure 2
Principal Component Analysis (PCA) of the JMC samples during different processing. (A) loading plot, (B) score plot.

4 Conclusions

The semi-finished products of JMC (i.e. CS, CPO, and PPO) and the final products (JMC1-JMC3) obtained from different stages of processing were analyzed for aroma profiles and volatile compositions. GC-MS results indicated that the compositions and concentrations of volatile compounds in testing samples changed significantly. Terpenes was the largest compound class found in CPO and PPO, but the content level decreased while cooking from semi-finished products to the final products. Meanwhile, alcohols, aldehydes, ketones were also inhibited when adding CPO and PPO into CS. Combined with GC-O analysis and PCA results, twenty-three compounds, including ethyl acetate, linalyl anthranilate, ethanol, (Z)-β-terpineol, linalool, l-terpinen-4-ol, a-terpineol, hexanal, 3-thujanone, 3-thujene, α-pinene, camphene, β-pinene, sabinene, 2-carene, α-phellandrene, myrcene, d-limonene, β-phellandrene, γ-terpinene, 1,8-cineole, anethol and eugenol were discovered might have great positive contributions to the characteristic aroma of JMC sauce.

Acknowledgements

National Natural Science Foundation of China (31960510), Special Support Plan of Shaanxi Province (TZ0432), Science and Technology Innovation Team of Shaanxi Province (2022TD-14), Shaanxi Natural Science Foundation (Grant No.2019JQ-665), Shaanxi key research and development program (Grant No. 2022NY-144 and 2021NY-132).

• Practical Application: The changes in volatile compounds are main factors that caused the difference in flavor quality among Jiao-ma chicken products. These results could provide a theoretical reference for the design of a modern high-quality Jiao-ma chicken processing technology.

References

• Chen, H. T., Sun, F. Y., Wang, D., Sun, B. G., & Zhang, Y. Y. (2017). Identification of Key aroma-active compounds of fried Zanthoxylum essential oil by aroma extract dilution analysis and gas chromatography-olfactometry-mass spectrometry. Shipin Yu Fajiao Gongye, 43, 191-198.
• Dhanya, K., & Sasikumar, B. (2010). Molecular marker based adulteration detection in traded food and agricultural commodities of plant origin with special reference to spices. Current Trends in Biotechnology and Pharmacy, 4, 454-489.
• Díaz-Maroto, M. C., Pérez-Coello, M. S., & Cabezudo, M. D. (2002). Headspace solid-phase microextraction analysis of volatile components of spices. Chromatographia, 55(11-12), 723-728. http://dx.doi.org/10.1007/BF02491788
  » http://dx.doi.org/10.1007/BF02491788
• Garruti, D. S., Mesquita, W. S., Magalhães, H. C. R., Araújo, Í. M. S., & Pereira, R. C. A. (2021). Odor-contributing volatile compounds of a new Brazilian tabasco pepper cultivar analyzed by HS-SPME-GC-MS and HS-SPME-GC-O/FID. Food Science and Technology (Campinas), 41(3), 696-701. http://dx.doi.org/10.1590/fst.18020
  » http://dx.doi.org/10.1590/fst.18020
• Grosch, W. (1993). Detection of potent odorants in foods by aroma extract dilution analysis. Trends in Food Science & Technology, 4(3), 68-73. http://dx.doi.org/10.1016/0924-2244(93)90187-F
  » http://dx.doi.org/10.1016/0924-2244(93)90187-F
• Ho, C. T., Zhang, Y., Shi, H., & Tang, J. (1989). Flavor chemistry of Chinese foods. Food Reviews International, 5(3), 253-287. http://dx.doi.org/10.1080/87559128909540855
  » http://dx.doi.org/10.1080/87559128909540855
• Jagella, T., & Grosch, W. (1999). Flavour and off-flavour compounds of black and white pepper (Piper nigrum L.) II. Odour activity values of desirable and undesirable odorants of black pepper. European Food Research and Technology, 209(1), 22-26. http://dx.doi.org/10.1007/s002170050450
  » http://dx.doi.org/10.1007/s002170050450
• Jiang, L., & Kubota, K. (2004). Differences in the volatile components and their odor characteristics of green and ripe fruits and dried pericarp of Japanese pepper (Xanthoxylum piperitum DC.). Journal of Agricultural and Food Chemistry, 52(13), 4197-4203. http://dx.doi.org/10.1021/jf030663a PMid:15212469.
  » http://dx.doi.org/10.1021/jf030663a
• Jirovetz, L., Buchbauer, G., Ngassoum, M. B., & Geissler, M. (2002). Aroma compound analysis of Piper nigrum and Piper guineense essential oils from Cameroon using solid-phase microextraction–gas chromatography, solid-phase microextraction–gas chromatography–mass spectrometry and olfactometry. Journal of Chromatography. A, 976(1-2), 265-275. http://dx.doi.org/10.1016/S0021-9673(02)00376-X PMid:12462618.
  » http://dx.doi.org/10.1016/S0021-9673(02)00376-X
• Jung, S., Jo, C., Kim, I. S., Nam, K. C., Ahn, D. U., & Lee, K. H. (2014). The influence of spices on the volatile compounds of cooked beef patty. Korean Journal for Food Science of Animal Resources, 34(2), 166-171. http://dx.doi.org/10.5851/kosfa.2014.34.2.166 PMid:26760934.
  » http://dx.doi.org/10.5851/kosfa.2014.34.2.166
• Kumar, O. A., Tata, S. S., & Rupavathi, T. (2014). Evaluation of genetic diversity in 21 cultivars of chili pepper (Capsicum annuum L.) using isozyme markers. European Journal of Experimental Biology, 4, 44-49.
• Lee, S. J., Umano, K., Shibamoto, T., & Lee, K. G. (2005). Identification of volatile components in basil (Ocimum basilicum L.) and thyme leaves (Thymus vulgaris L.) and their antioxidant properties. Food Chemistry, 91(1), 131-137. http://dx.doi.org/10.1016/j.foodchem.2004.05.056
  » http://dx.doi.org/10.1016/j.foodchem.2004.05.056
• Li, H., Li, X., Zhang, C. H., Wang, J. Z., Tang, C. H., & Chen, L. L. (2016). Flavor compounds and sensory profiles of a novel Chinese marinated chicken. Journal of the Science of Food and Agriculture, 96(5), 1618-1626. http://dx.doi.org/10.1002/jsfa.7263 PMid:25988332.
  » http://dx.doi.org/10.1002/jsfa.7263
• Marais, J. (2017). Terpenes in the aroma of grapes and wines: a review. South African Journal of Enology and Viticulture, 4(2), 49-58. http://dx.doi.org/10.21548/4-2-2370
  » http://dx.doi.org/10.21548/4-2-2370
• National Institute of Standards and Technology – NIST, & U.S. Secretary of Commerce. (2022). Gaithersburg: NIST Standard Reference Data. http://webbook.nist.gov/chemistry/name-ser.html
  » http://webbook.nist.gov/chemistry/name-ser.html
• Pino, J., Sauri-Duch, E., & Marbot, R. (2006). Changes in volatile compounds of Habanero chile pepper (Capsicum chinense Jack. cv. Habanero) at two ripening stages. Food Chemistry, 94(3), 394-398. http://dx.doi.org/10.1016/j.foodchem.2004.11.040
  » http://dx.doi.org/10.1016/j.foodchem.2004.11.040
• Rahman, F. U., Nawaz, M. A., Liu, R., Sun, L., Jiang, J., Fan, X., Liu, C., & Zhang, Y. (2022). Evaluation of volatile aroma compounds from Chinese wild grape berries by Headspace-SPME with GC-MS. Food Science and Technology (Campinas), 42, e54320. http://dx.doi.org/10.1590/fst.54320
  » http://dx.doi.org/10.1590/fst.54320
• Raghavan, S. (2006). Handbook of spices, seasonings and flavorings Boca Raton: CRC Press. http://dx.doi.org/10.1201/b13597
  » http://dx.doi.org/10.1201/b13597
• Tian, H. L., Wang, P., Zhan, P., Yan, H. Y., Zhou, W. J., & Zhang, F. (2017). Effects of β-glucosidase on the aroma characteristics of flat peach juice as assessed by descriptive sensory analysis and gas chromatography and compared by partial least squares regression. Lebensmittel-Wissenschaft + Technologie, 82, 113-120. http://dx.doi.org/10.1016/j.lwt.2017.04.029
  » http://dx.doi.org/10.1016/j.lwt.2017.04.029
• Tian, H., Zhan, P., Li, W., Zhang, X., He, X., Ma, Y., Guo, Z., & Zhang, D. (2014). Contribution to the aroma characteristics of mutton process flavor from oxidized suet evaluated by descriptive sensory analysis, gas chromatography, and electronic nose through partial least squares regression. European Journal of Lipid Science and Technology, 116(11), 1522-1533. http://dx.doi.org/10.1002/ejlt.201300473
  » http://dx.doi.org/10.1002/ejlt.201300473
• Varlet, V., & Fernandez, X. (2010). Sulfur-containing volatile compounds in seafood: occurrence, odorant properties and mechanisms of formation. Food science and technology international = Ciencia y tecnologia de los alimentos internacional, 16(6), 463-503. http://dx.doi.org/10.1177/1082013210379688 PMid:21339165.
  » http://dx.doi.org/10.1177/1082013210379688
• Wang, L. M., Chen, Q., Zhong, Z., Yi, Y., Hou, W. F., & Wang, H. X. (2022). Research on variation of volatile compounds of Cinnamomum cassia Presl in different processing stage of stewed beef. Food Science and Technology (Campinas), 42, e09322. http://dx.doi.org/10.1590/fst.09322
  » http://dx.doi.org/10.1590/fst.09322
• Yang, X. (2008). Aroma constituents and alkylamides of red and green huajiao (Zanthoxylum bungeanum and Zanthoxylum schinifolium). Journal of Agricultural and Food Chemistry, 56(5), 1689-1696. http://dx.doi.org/10.1021/jf0728101 PMid:18271544.
  » http://dx.doi.org/10.1021/jf0728101
• Zhang, D., Ji, H.-W., Luo, G.-X., Chen, H., Liu, S.-C., & Mao, W.-J. (2022). Insight into aroma attributes change during the hot-air-drying process of white shrimp using GC-MS, E-Nose and sensory analysis. Food Science and Technology (Campinas), 42, e70820. http://dx.doi.org/10.1590/fst.70820
  » http://dx.doi.org/10.1590/fst.70820
• Zhan, P., Tian, H. L., Zhang, X. M., & Wang, L. P. (2013). Contribution to aroma characteristics of mutton process flavor from the enzymatic hydrolysate of sheep bone protein assessed by descriptive sensory analysis and gas chromatography olfactometry. Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences, 921-922, 1-8, 921-922. http://dx.doi.org/10.1016/j.jchromb.2012.12.026 PMid:23416288.
  » http://dx.doi.org/10.1016/j.jchromb.2012.12.026

Publication Dates

• Publication in this collection
  08 July 2022
• Date of issue
  2022

History

• Received
  08 May 2022
• Accepted
  14 June 2022