Screening method of salty flavor enhancing aroma compound derived from boiled salted duck

Abstract

The invention discloses a screening method of salty flavor-enhancing compounds sourced from boiled salted ducks, and belongs to the technical field of food flavoring agents. The method comprises the following steps: selecting healthy sensory evaluation participants, performing simulated oral chewing treatment on a boiled salted duck sample, and collecting chewing substances at different time points; separating and detecting aroma compounds in the collected chew powder; comparing retention indexes, database spectrograms, standard substances and literature data to preliminarily identify aroma compounds; calculating the odor activity value of each aroma compound, and screening the aroma compounds of which the OAV is greater than or equal to 1; pearson correlation analysis is adopted, and aroma compounds significantly related to Na < + > and K < + > content and salty taste sensory attributes are screened. The salty flavor enhancing compound disclosed by the invention has the best salty flavor enhancing effect in a 0.5% NaCl solution, wherein the enhancing effects of heptanal and octanal are most obvious; the salty seasoning is wide in application range and can be added into various products needing salty seasoning, such as seasonings, meat products and snack foods.

Description

Technical Field

[0001] This invention belongs to the field of food flavoring technology, specifically relating to a method for screening salty flavor-enhancing aroma compounds derived from salted duck. Background Technology

[0002] Nanjing salted duck, a typical representative of traditional low-temperature poultry products in China, is renowned both domestically and internationally for its tender meat and unique aroma. Its processing typically combines dry and wet curing methods to impart its distinctive flavor and quality. In meat processing, salt (primarily NaCl) is not only a core seasoning substance, providing the product with a basic salty taste and enhancing its flavor profile, but it also plays a crucial role in extending shelf life and improving texture and color by regulating lipid oxidation rates, inhibiting microbial growth, and promoting protein structure transformation. Therefore, it is an indispensable component in the traditional processing of Nanjing salted duck.

[0003] However, excessive salt intake has been proven to be significantly associated with the risk of developing various chronic diseases such as hypertension, cardiovascular disease, and diabetes, becoming an important factor affecting public health. The World Health Organization (WHO) has clearly set a goal of reducing global sodium intake by 30% by 2025, and my country's "Healthy China 2030" plan also requires a gradual reduction in the average daily salt intake per capita. The development of salt reduction technology for meat products has become an urgent task for the food industry to meet health needs and adapt to industrial upgrading.

[0004] Existing strategies for reducing salt in meat products mainly fall into three categories: First, improving the dispersibility of salt in products by changing its physical form (such as microencapsulation and nano-sizing). However, such methods are complex to prepare and costly, making them difficult to apply on a large scale in traditional meat processing. Second, partially replacing NaCl with non-sodium substitutes such as potassium and calcium salts. However, these substitutes can easily introduce unpleasant flavors such as bitterness, disrupting the flavor balance of traditional products. Third, optimizing processing technologies (such as high-pressure assisted curing and ultrasonic treatment) to promote salt penetration. However, these technologies have high barriers to entry and limited compatibility with the flavors of traditional products such as Nanjing salted duck.

[0005] Odor-induced saltiness enhancement (OISE), as an emerging salt reduction technology, can enhance the perception of saltiness without increasing salt content through cross-modal interactions between olfaction and taste. The OISE effect in the postnasal olfactory pathway is particularly significant. Previous studies have confirmed that characteristic aroma compounds of some meats (such as smoked meat and bacon) can enhance the perception of saltiness through this mechanism. However, aroma compounds with OISE effects in Nanjing salted duck have not yet been systematically identified. Their mechanism of action and application schemes in salt reduction processing remain a technological gap, and cannot provide effective support for the salt reduction and quality improvement of Nanjing salted duck. Summary of the Invention

[0006] The first technical problem to be solved by this invention is to provide a method for screening salty aroma-enhancing compounds derived from salted duck. This method can efficiently enrich and identify target compounds, providing a methodological reference for screening active ingredients in similar products. The second technical problem to be solved by this invention is to provide a method for screening salty aroma-enhancing compounds derived from salted duck to obtain salty aroma-enhancing compounds, which are five salty aroma-enhancing compounds: pentanal, hexanal, heptanal, octanal, and 2-pentylfuran. The third technical problem to be solved by this invention is to provide the application of these salty aroma-enhancing compounds in the preparation of seasonings or foods. The fourth technical problem to be solved by this invention is to provide the application of these salty aroma-enhancing compounds in reducing the use of table salt.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A method for screening salty flavor-enhancing aroma compounds derived from salted duck includes the following steps:

[0009] 1) Take salted duck leg meat, remove bones and skin, weigh a quantitative sample, and store it in a sealed container at low temperature for later use;

[0010] 2) Select healthy sensory evaluation participants and simulate oral chewing treatment on the salted duck samples from step 1), and collect the chewed material at different time points;

[0011] 3) The chewed material collected in step 2) was ground into powder using liquid nitrogen, and the aroma compounds in the powder were separated and detected by GC-MS;

[0012] 4) Aroma compounds were preliminarily identified by comparing retention indices, database spectra, standards, and literature data;

[0013] 5) Calculate the odor activity value of each aroma compound and screen aroma compounds with OAV≥1;

[0014] 6) A transient sensory dominance analysis of salted duck was conducted to assess the dynamic aroma perception of salted duck via the postnasal pathway.

[0015] 7) Pearson correlation analysis was used to screen for correlations with Na. + K + Aroma compounds whose content and salty-savory sensory properties are significantly related.

[0016] Furthermore, in step 1), the salted duck is stored at a temperature of -20℃ and the storage time does not exceed 3 months.

[0017] Further, in step 2), the parameters for simulating oral chewing treatment are: 3.0g per sample, 30 seconds of chewing time, 2 chewing times per second, and collection time points of 0, 5, 10, 15, 20, 25, and 30 seconds.

[0018] Further, in step 3), headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (GC-MS) is used to separate and detect aroma compounds in the powder. The headspace solid-phase microextraction conditions are as follows: the sample is incubated at 60°C for 10 minutes, extracted with DVB / CAR / PDMS fiber for 20 minutes, and desorbed without splitting at 250°C for 5 minutes; gas chromatography uses an HP-5MS capillary column for separation, with helium as the carrier gas, a flow rate of 1.0 mL / min, and a specific column temperature program; the mass spectrometry ion source temperature is 280°C, the ionization voltage is 70 eV, and the scan range is 35-550 m / z.

[0019] Further, in step 5), the odor activity value is calculated by the ratio of compound concentration to olfactory threshold.

[0020] Furthermore, in step 5), the aroma compounds with OAV≥1 include 9 aldehydes, 13 alcohols, 2 ketones, 4 terpenes, and 2 other compounds.

[0021] Furthermore, in step 7), the concentration of the NaCl solution is 0.25~0.75%.

[0022] Furthermore, the salty aroma-enhancing compounds obtained by the screening method for salted duck source have an OAV ≥ 1 and are similar to Na... + K + The compounds whose content showed a significant positive correlation with, and were strongly positively correlated with, the sensory attributes of salty and savory flavor were pentanal, hexanal, heptanal, octanal, and 2-pentylfuran.

[0023] Furthermore, the application of the salty aroma-enhancing compound in the preparation of condiments or food.

[0024] Furthermore, the application of the salty flavor-enhancing aroma compound in reducing salt consumption.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] (1) This invention is the first to screen out five salty flavor-enhancing compounds, namely pentanal, hexanal, heptanal, octanal and 2-pentylfuran, from salted duck. These compounds are naturally derived and have high safety, which solves the problems of poor flavor and questionable safety of traditional salt-reducing additives.

[0027] (2) The salty aroma-enhancing compounds of the present invention have the best salty-enhancing effect in 0.5% NaCl solution, among which heptanal and octanal have the most significant enhancing effect.

[0028] (3) This invention has a wide range of applications and can be added to various products that require salty seasoning, such as condiments, meat products, and snack foods. While reducing the amount of salt used by more than 30%, it ensures the salty taste of the product, which is in line with the development trend of healthy food and has important economic value and social significance. Attached Figure Description

[0029] Figure 1 (A) A heat map of NWSD aroma compounds in the postnasal olfactory pathway of this application, and (B) A Sankey diagram based on OAV values;

[0030] Figure 2 This is a dynamic aroma perception diagram of NWSD in the postnasal olfactory pathway of this application;

[0031] Figure 3 For the present application (A) Na in duck chewing matter and saliva + Variation diagram, (B) K in duck chewing matter and saliva + Concentration change graph;

[0032] Figure 4 The following diagrams are provided for this application: (A) Pearson correlation network diagram of sodium / potassium ions and aroma compounds in duck chewing matter and saliva; (B) correlation analysis diagram of dynamic sensory evaluation results and aroma compounds in NWSD; (C) Venn diagram of aroma compounds related to OAV>1, sodium / potassium ion ratio and salty sensory characteristics; and (D) diagram of selected aroma compounds used to evaluate the odor-induced salty enhancement effect.

[0033] Figure 5 The following diagrams show the results of odor-induced saltiness enhancement in this application: (A) Diagrams showing the saltiness enhancement effect of aroma compounds at 0%, 0.25%, 0.50%, and 0.75% NaCl solution concentrations, evaluated via the retronasal olfactory pathway; (B) Diagrams showing the saltiness enhancement effect of aroma compounds at different concentrations, evaluated via the retronasal olfactory pathway at a fixed NaCl concentration. Detailed Implementation

[0034] The present invention will be further illustrated below with reference to specific embodiments. These embodiments are implemented based on the technical solutions of the present invention, and it should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0035] The Nanjing salted duck samples used in the following examples were purchased from Nanjing Professor Huang Food Technology Co., Ltd. (Nanjing, Jiangsu Province). This product strictly adheres to the traditional processing techniques for geographical indication products, uses Cherry Valley ducks as raw materials, and has complete traceability information. The samples were stored in vacuum-sealed bags at -20°C and used within 3 months.

[0036] The methyl 2-methyl-3-heptanone (≥95%), pentanal (≥95%), hexanal (≥99%), heptanal (≥98%), octanal (≥99%), and 2-pentylfuran (≥95%) used in the following examples were purchased from Shanghai Yuanye Biotechnology Co., Ltd. (Shanghai, China). Food-grade pentanal, hexanal, heptanal, octanal, decanal (≥98%), dodecanal (≥95%), 1-octen-3-ol (≥98%), and 2-pentylfuran (purity >98%) were purchased from Wuhan Narabai Biotechnology Co., Ltd. (Wuhan, China).

[0037] Example 1

[0038] (1) After removing the bones and skin from Nanjing salted duck, take the leg meat part, weigh 3.0g for each portion, vacuum pack it and store it at -20℃.

[0039] (2) Twelve healthy volunteers (6 males and 6 females, aged 25-30 years) were selected and subjected to sensory tests such as taste and smell recognition before simulating oral chewing. The chewing time was 30 seconds and the chewing frequency was 2 times / second. The chewed material was collected at 0, 5, 10, 15, 20, 25 and 30 seconds. The samples at each time point were mixed and frozen at -80℃.

[0040] (3) The frozen chewed food was ground into powder using liquid nitrogen. 2.0 g of the powder was accurately weighed and placed in a 20 mL headspace vial. 10 μL of internal standard solution (2-methyl-3-heptanone, 0.204 μg / μL) was added, and the vial was sealed with a polytetrafluoroethylene diaphragm. Extraction was performed using DVB / CAR / PDMS fiber at 60 °C for 20 min, followed by desorption at 250 °C for 5 min. The extract was then injected into a gas chromatograph-mass spectrometer (ThermoScientific TSQ 1310 / 9000) for detection. The gas chromatographic column was an HP-5MS (30 m × 0.25 mm, membrane thickness 0.25 μm), the carrier gas was helium, the flow rate was 1.0 mL / min, and the column temperature program was: 40 °C for 3 min, increasing to 70 °C at 5 °C / min, increasing to 130 °C at 10 °C / min, and increasing to 250 °C at 10 °C / min for 3 min. Mass spectrometry conditions: ion source temperature 280℃, ionization voltage 70eV, scan range 35-550m / z.

[0041] (4) By determining the retention index of C7-C30 n-alkanes, and combining it with NIST14 database spectral comparison, standard comparison, and literature data, a total of 30 aroma compounds were identified, including 9 aldehydes, 13 alcohols, 2 ketones, 4 terpenes, and 2 other compounds. Based on the quantitative results of each compound and the known olfactory threshold, the OAV value was calculated, and 10 odor-active compounds with OAV ≥ 1 were screened out, among which hexanal, octanal, and nonanal all had OAV values ​​exceeding 30. Figure 1 As shown in Table 1-2.

[0042] Table 1. Concentrations of aroma compounds in NSWD after chewing determined by gas chromatography-mass spectrometry.

[0043]

[0044]

[0045] Table 2. OAV values ​​of aroma compounds in chewed NSWD determined by gas chromatography-mass spectrometry

[0046]

[0047]

[0048] (5) In step (2), 12 individuals without rhinitis, oral diseases, or a particular preference for salted duck were selected. After screening through taste and smell recognition tests, they underwent four specialized training sessions to determine the four core sensory attributes: meat aroma, fat aroma, fishy aroma, and salty aroma. Simultaneously, the evaluators were familiarized with the concept of dominant sensory perception and the operation of the Sensmake software. Evaluations were conducted at fixed times in a constant temperature and humidity environment of 25℃ and 60% relative humidity. Each sample consisted of 3g of boneless and skinless salted duck leg meat. After placing the sample in their mouths, the evaluators started the software and chewed at a fixed frequency of 2 times / second for 30 seconds, recording the dominant aroma attribute every 5 seconds. Multiple selections or skipping of a specific attribute were allowed. After each sample test, the evaluators rested for 5 minutes and cleaned their mouths. The experiment was repeated 3 times per person, resulting in 36 test data points. TDS curves were plotted using Origin software, and the random and significance lines were calculated to determine the attribute contribution. Figure 2 As shown.

[0049] Depend on Figure 2 The TDS curves for the four aroma attributes of NWSD are shown. The chance line and significance line are 0.250 and 0.346, respectively. Attributes below the chance line are considered to contribute little to overall perception, while attributes above the significance line are considered dominant features. The TDS results show that the aroma characteristics of NWSD change significantly in the postnasal pathway. Meaty and salty aromas are two key olfactory attributes, both above the chance and significance lines, and they maintain a prominent position throughout the chewing process, persisting for a long time, indicating that these two attributes significantly contribute to the aroma perception of NWSD (p < 0.05). From the time of mouth placement to 15 seconds of chewing, meaty aroma is the dominant attribute, while salty aroma dominates between 15 and 30 seconds of chewing. Earthy and fatty aromas consistently remain below the chance line, indicating that these attributes do not play a key role in the perception of NWSD. In summary, meaty and salty aromas are dominant in the oral processing of NWSD. Furthermore, aroma attributes are also given a temporal characteristic, indicating that the release of the corresponding aromas changes dynamically during oral processing.

[0050] (6) Pearson correlation analysis was performed using Omic Studio tools. The results showed that pentanal, hexanal, heptanal, octanal, 2-pentylfuran and Na + K + The content showed a significant positive correlation (R>0.8, p<0.05) and a strong positive correlation with the salty-savory sensory attributes (R>0.7, p<0.05). Based on OAV≥1, these 5 compounds were selected as candidates. (See...) Figure 3-4 As shown in Table 3-4.

[0051] Table 3. Pearson correlation analysis of the relationship between Na+ and K+ in saliva and residue and aroma compounds of NWSD

[0052]

[0053]

[0054] Table 4. Pearson correlation analysis of released aroma compounds and TDS results

[0055]

[0056]

[0057] (7) Five candidate compounds were prepared into solutions with concentrations of 1000, 250, 500, 500, and 275 μg / L, respectively, and added to 0.25%, 0.5%, and 0.75% NaCl solutions, respectively, with a NaCl-free solution as a control. Simultaneously, solutions of the five compounds were prepared in gradients of 5-1000 μg / L and added to NaCl solutions of fixed concentrations. Twelve sensory evaluators wearing nose clips were used to score the saltiness. The results are as follows: Figure 5 The results showed that all five compounds significantly enhanced the perceived saltiness at all tested NaCl concentrations (p<0.05), with the strongest enhancement effect observed in 0.5% NaCl solution. Heptanal had the highest OISE value at 0.96, followed by octanal, then hexanal, pentanal, and 2-pentylfuran. These five compounds were ultimately identified as saltiness-enhancing aroma compounds.

[0058] Example 2

[0059] (1) Commercially available low-salt soy sauce (NaCl content ≤ 8%) was selected as the base raw material, and heptanal, octanal (concentration of 100 μg / L), hexanal, pentanal, and 2-pentylfuran (concentration of 150 μg / L) were added to prepare flavored soy sauce samples. At the same time, low-salt soy sauce without added aroma compounds was set as the control group, and ordinary soy sauce (NaCl content 12%) was set as the positive control group.

[0060] (2) Twenty trained sensory evaluators were invited to score the saltiness intensity and flavor harmony of the samples on a 10-point scale. The scoring criteria were: 0 points for saltiness intensity (no saltiness) and 10 points for saltiness intensity (extremely salty); 0 points for flavor harmony (very poor) and 10 points for flavor harmony (excellent).

[0061] The saltiness-enhancing aroma compounds added to the soy sauce samples showed significantly higher saltiness intensity scores (8.5-9.2 points) than the control group (6.3 points), but no significant difference from the positive control group (9.0 points); the flavor harmony scores (8.8-9.5 points) were higher than both the control group (7.2 points) and the positive control group (8.5 points). These results indicate that the saltiness-enhancing aroma compounds of this invention can reduce the salt content in soy sauce by 20% while maintaining saltiness perception and improving flavor harmony.

[0062] Example 3

[0063] (1) Based on the traditional process of Nanjing salted duck, the amount of salt added was reduced by 30% (from the traditional 6% to 4.2%), and heptanal (80 μg / kg), octanal (80 μg / kg), hexanal (120 μg / kg), pentanal (120 μg / kg), and 2-pentylfuran (120 μg / kg) were added respectively to prepare 5 groups of low-salt salted duck samples; the low-salt salted duck without added aroma compounds was set as the control group, and the traditional salted duck was set as the positive control group.

[0064] (2) The saltiness intensity (sensory score), microbial indicators (total bacterial count, Escherichia coli), texture characteristics (hardness, elasticity) and shelf life of each group of samples were tested.

[0065] Five groups of low-salt salted duck samples with added aroma compounds showed saltiness intensity scores (8.2-8.8 points) that were close to the positive control group (8.6 points) but significantly higher than the control group (6.1 points). Microbiological indicators all met the requirements of GB 2726-2016 "National Food Safety Standard for Cooked Meat Products" (total bacterial count ≤30,000 CFU / g, E. coli not detected). In terms of texture properties, hardness and elasticity showed no significant difference from the positive control group. The shelf life of all samples reached 6 months, consistent with traditional salted duck. This indicates that the application of saltiness-enhancing aroma compounds in low-temperature meat products can achieve a 30% reduction in salt content while maintaining saltiness, without affecting the product's microbiological safety, texture, and shelf life.

[0066] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for screening salty flavor-enhancing aroma compounds derived from salted duck, characterized in that: Comprising the following steps: 1) Take salted duck leg meat, remove the bone and skin, and then take a quantitative sample, place it in a sealed container, and store it at low temperature for standby; 2) Select healthy sensory evaluation participants, simulate oral chewing of the salted duck sample in step 1), and collect the chewed material at different time points; 3) Grind the chewed material collected in step 2) into powder with liquid nitrogen, and separate and detect the aroma compounds in the powder by GC-MS; 4) Preliminary identification of aroma compounds by retention index, database spectrum, standard and literature data comparison; 5) Calculate the odor activity value of each aroma compound, and screen the aroma compounds with OAV≥1; 6) Perform temporary sensory dominance analysis on salted duck to evaluate the dynamic aroma perception of the post-nasal pathway of salted duck; 7) Using Pearson correlation analysis, screening aroma compounds significantly correlated with Na + , K + content and salty sensory attributes.

2. The method for screening salty flavor-enhancing aroma compounds derived from salted duck according to claim 1, characterized in that: In step 1), the storage temperature of salted duck is-20℃, and the storage time is not more than 3 months.

3. The method for screening salty flavor-enhancing aroma compounds derived from salted duck according to claim 1, characterized in that: In step 2), the parameters of simulated oral chewing are as follows: sample weight 3.0g, chewing time 30 seconds, chewing frequency 2 times / second, and collection time points 0, 5, 10, 15, 20, 25, 30 seconds.

4. The method for screening salty flavor-enhancing aroma compounds derived from salted duck according to claim 1, characterized in that: In step 3), headspace solid-phase microextraction combined with gas chromatography-mass spectrometry is used to separate and detect the aroma compounds in the powder, and the conditions of headspace solid-phase microextraction are as follows: the sample is incubated at 60℃ for 10 minutes, DVB / CAR / PDMS fiber extraction is used for 20 minutes, and desorption is performed at 250℃ for 5 minutes without splitting; gas chromatography uses HP-5MS capillary column for separation, carrier gas is helium, flow rate is 1.0 mL / min, and temperature is raised according to a specific column temperature program; the ion source temperature of mass spectrometry is 280℃, the ionization voltage is 70 eV, and the scanning range is 35-550 m / z.

5. The method for screening salty flavor-enhancing aroma compounds derived from salted duck according to claim 1, characterized in that: In step 5), the odor activity value is calculated by the ratio of compound concentration to olfactory threshold.

6. The method for screening salty flavor-enhancing aroma compounds derived from salted duck according to claim 1, characterized in that: In step 5), the aroma compounds with OAV≥1 include 9 aldehydes, 13 alcohols, 2 ketones, 4 terpenes and 2 other compounds.

7. The method for screening salty flavor-enhancing aroma compounds derived from salted duck according to claim 1, characterized in that: In step 7), the concentration of NaCl solution is 0.25-0.75%.

8. The salted duck derived salty taste enhancing aroma compound obtained by the screening method according to any one of claims 1 to 7, characterized by: OAV≥1, with Na + , K + content showed significant positive correlation, and the compounds with strong positive correlation with salty taste sensory attributes were pentanal, hexanal, heptanal, octanal and 2-pentyl furan.

9. Use of the salty taste-enhancing aroma compound of claim 8 in the preparation of a condiment or food.

10. Use of the salty taste-enhancing aroma compound of claim 8 in reducing the use of table salt.

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