A method for roasting sesame seeds under vacuum conditions

Abstract

The application provides a method for roasting sesame seeds under vacuum conditions, and relates to the sesame roasting technical field. The method can improve the processing properties of sesame seeds and roast the sesame seeds to have pure and more intense flavor by normal pressure conditioning and vacuum high-temperature roasting. Meanwhile, the method can avoid inducing excessive oxidation of lipids, producing burnt, smelly and other peculiar smells, and carcinogenic substances such as benzopyrene. The method is simple in operation, low in cost and suitable for industrial application.

Description

Technical Field

[0001] This invention relates to the field of sesame roasting technology, and more specifically, to a method for roasting sesame seeds under vacuum conditions. Background Technology

[0002] Sesame is a high-quality oil crop and a specialty agricultural product, with 55% of sesame used for sesame oil production. The core of the unique aroma of sesame oil lies in the high-temperature roasting process of sesame. Existing sesame roasting processes are mainly divided into three categories: First, roasting is carried out by directly heating the roasting furnace with heat sources such as wood, coal, natural gas, or electromagnetic fields; second, high-temperature roasting is achieved by using a double-layer roasting furnace and uniformly heating the inner wall with heat-conducting oil; and third, roasting is achieved by directly heating the sesame with microwaves. All of the above processes need to be carried out under natural atmospheric pressure, and the roasting temperature is usually controlled between 180-210℃.

[0003] During atmospheric pressure roasting, sesame seeds are exposed to an oxygen-rich environment for an extended period, making them highly susceptible to oxidation at high temperatures. When roasting exceeds 10 minutes, sesame seeds are prone to scorching, darkening of color, and impure aroma, accompanied by off-flavors such as burnt and rancid tastes. More seriously, excessive lipid oxidation can induce the formation of carcinogens such as benzo[a]pyrene, glycidyl esters, and acrylamide, posing food safety risks. Furthermore, open-air atmospheric pressure processing generates large amounts of fumes, dust, and exhaust gases, polluting the production environment and surrounding ecosystem, which does not meet the requirements of green production. Therefore, we have proposed an improvement: a method for roasting sesame seeds under vacuum conditions. Summary of the Invention

[0004] This invention provides a method for roasting sesame seeds under vacuum conditions, comprising the following steps: S1: Wash the sesame seeds with water and roast them in a vacuum roasting pan. S2: Quickly create a vacuum to raise the temperature of the vacuum seed roasting pan and heat it to the roasting stage; S3: Stop heating and cool down under vacuum conditions to complete the stir-frying process.

[0005] As a preferred technical solution of this application, in S1, the roasting temperature range is 100-120℃, and the roasting time is 15-25 minutes.

[0006] As a preferred technical solution of this application, in S1, the moisture content of the sesame seeds after roasting is 8%-10%.

[0007] As a preferred technical solution of this application, in S2, the vacuum is rapidly evacuated to between 0.03-0.04 MPa.

[0008] As a preferred technical solution of this application, in S2, the vacuum is rapidly evacuated to between 0.05-0.06 MPa.

[0009] As a preferred technical solution of this application, in S2, the vacuum is rapidly evacuated to between 0.07-0.08 MPa.

[0010] As a preferred technical solution of this application, in S2, the temperature of the improved vacuum seed roasting pan is 180-210℃.

[0011] As a preferred technical solution of this application, in S2, the sesame seeds are roasted for 20-25 minutes.

[0012] As a preferred technical solution of this application, in S3, the temperature is reduced to 30-50°C under vacuum conditions.

[0013] As a preferred technical solution of this application, in S1, the water washing is a running water rinse, and the water washing time is 3-5 minutes to remove dust from the surface of the sesame seeds.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This application involves conditioning sesame seeds under normal pressure and high-temperature vacuum roasting, which improves the processing properties of sesame seeds and produces a purer and richer aroma. At the same time, it avoids inducing excessive lipid oxidation, which can produce burnt, rancid odors and carcinogenic substances such as benzo[a]pyrene. Furthermore, this application is simple to operate, low in cost, and suitable for industrial application. Attached Figure Description

[0015] Figure 1 A flowchart of a first embodiment of the method for roasting sesame seeds under vacuum conditions provided in this application; Figure 2 A flowchart of a second embodiment of the method for roasting sesame seeds under vacuum conditions provided in this application; Figure 3 A flowchart of a third embodiment of the method for roasting sesame seeds under vacuum conditions provided in this application. Detailed Implementation

[0016] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0017] It should be noted that, unless otherwise specified, the embodiments and features and technical solutions in the embodiments of the present invention can be combined with each other.

[0018] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. The sesame aroma compounds described in the following examples mainly include the sum of core aroma compounds such as pyrazines (2-ethyl-3,5-dimethylpyrazine, 2-ethylpyrazine), sulfur-containing compounds (methylthion, dimethyl disulfide, dimethyl trisulfide), and 5-methylfurfural produced after sesame roasting.

[0019] Example 1, please refer to Figure 1 A method for roasting sesame seeds under vacuum conditions, comprising the following steps: S1: Wash the sesame seeds and roast them in a vacuum roasting pan at a temperature of 100-120℃ for 15-25 minutes. The moisture content of the roasted sesame seeds should be 8%-10% to enhance their aroma production. Compared to direct high-temperature roasting, the low-temperature environment of 100-120℃ can reduce the destruction of internal oils and flavor precursors in sesame seeds by high temperatures, and gently activate flavor precursors such as sugars and amino acids inside the sesame seeds. This lays the foundation for subsequent Maillard reactions and fat degradation to produce aroma. At the same time, controlling the moisture content of the sesame seeds at 8%-10% can prevent the sesame seeds from drying out and burning during subsequent roasting. It can also promote the opening of the internal pores of the sesame seeds through appropriate evaporation of moisture, thereby enhancing the overall aroma production potential of the sesame seeds and effectively strengthening their ability to generate aroma. S2: Rapid vacuuming raises the temperature of the vacuum roasting pan to the roasting stage; rapid vacuuming to 0.03-0.04 MPa increases the pan temperature to 180-210℃, roasting the sesame seeds for 15 minutes, with the rapid vacuuming operation completed within 5 minutes; fully activating the Maillard reaction to produce pure aroma; rapid vacuuming within 5 minutes quickly creates a low-pressure sealed environment, and the high vacuum of 0.03-0.04 MPa significantly reduces the oxygen content in the air, effectively inhibiting the oxidation and deterioration of sesame oils and preventing rancid and oxidized off-flavors; the high temperature of 180-210℃ combined with the vacuum environment precisely triggers the Maillard reaction and the thermal degradation reaction of fats in the sesame seeds, generating core aroma substances such as pyrazines and furans; the short roasting time of 15 minutes is suitable for this vacuum parameter and can quickly activate the aroma; S3: Stop heating and cool down to 30-50℃ under vacuum conditions to complete the roasting process; constant temperature cooling under vacuum conditions, unlike rapid cooling under normal pressure, can stop the continuous oxidation reaction and excessive Maillard reaction at high temperature, lock in the generated aroma substances in time, and prevent the sesame from being continuously carbonized and flavor substances from being lost due to residual heat; at the same time, slow cooling can avoid the sesame from cracking and uneven oil release due to sudden temperature changes, thus preserving the sesame's complete appearance and original oil nutrition; Furthermore, in S1, the water washing is a running water rinse for 3-5 minutes to remove dust from the surface of the sesame seeds.

[0020] In this embodiment, the total amount of core aroma substances in the roasted sesame seeds increased by 75.2%.

[0021] Example 2, please refer to Figure 2 A method for roasting sesame seeds under vacuum conditions, comprising the following steps: S1: Wash the sesame seeds with water and roast them in a vacuum roasting pan at a temperature of 100-120℃ for 15-25 minutes. The moisture content of the roasted sesame seeds should be 8%-10% to enhance their aroma production. S2: Rapid vacuuming raises the temperature of the vacuum roasting pan to the roasting stage; rapid vacuuming to between 0.05-0.06 MPa increases the pan temperature to 180-210℃, roasting the sesame seeds for 20 minutes, with the rapid vacuuming operation completed within 5 minutes; this fully stimulates the Maillard reaction, producing a pure aroma; the 0.05-0.06 MPa pressure environment ensures more even heating of the sesame seeds, preventing localized overheating and carbonization; simultaneously extending the roasting time to 20 minutes provides ample reaction time for the Maillard reaction and fat degradation reaction within the sesame seeds to fully proceed, maximizing the conversion into core aroma compounds; S3: Stop heating and cool down to 30-50℃ under vacuum conditions to complete the stir-frying process.

[0022] Furthermore, in S1, the water washing is a running water rinse for 3-5 minutes to remove dust from the surface of the sesame seeds.

[0023] In this embodiment, the total amount of core aroma compounds in the roasted sesame seeds increased by 175.6%. The aroma was pure and free of burnt smell. The moderate vacuum of 0.05-0.06 MPa combined with the standard roasting time of 20 minutes achieved a precise balance between the intensity of the thermal reaction and the reaction time, resulting in a full Maillard reaction without excessive pyrolysis and effective inhibition of lipid oxidation.

[0024] Example 3, please refer to Figure 3 A method for roasting sesame seeds under vacuum conditions, comprising the following steps: S1: Wash the sesame seeds with water and roast them in a vacuum roasting pan at a temperature of 100-120℃ for 15-25 minutes. The moisture content of the roasted sesame seeds should be 8%-10% to enhance their aroma production. S2: Rapid vacuuming raises the temperature of the vacuum roasting pan to the roasting stage; rapid vacuuming to between 0.07-0.08 MPa, resulting in a roasting temperature of 180-210℃ for sesame seeds, with a roasting time of 25 minutes. The rapid vacuuming operation is completed within 5 minutes, fully stimulating the Maillard reaction and producing a pure aroma. This embodiment uses a low vacuum of 0.07-0.08 MPa and a long-lasting roasting process of 25 minutes. The rapid vacuuming within 5 minutes quickly creates a low-oxygen, sealed environment, fundamentally inhibiting excessive lipid oxidation, rancidity, and the production of carcinogens such as benzo[a]pyrene. S3: Stop heating and cool down to 30-50℃ under vacuum conditions to complete the stir-frying process.

[0025] Furthermore, in S1, the water washing is a running water rinse for 3-5 minutes to remove dust from the surface of the sesame seeds.

[0026] In this embodiment, the total amount of core aroma compounds in the roasted sesame seeds increased by 243.7%. There was no burnt smell in the aroma; the aroma was pure and rich. The 0.07-0.08 MPa vacuum degree was suitable for 25 minutes of long-term roasting, which ensured a thorough and gentle thermal reaction, and the conversion rate of flavor precursors reached its peak, resulting in a large enrichment of core aroma compounds. At the same time, the low-oxygen vacuum environment suppressed oxidation and carbonization side reactions throughout the process.

[0027] This application also includes atmospheric pressure roasting as a reference, comparing it with the above embodiments to visually demonstrate the difference between existing atmospheric pressure roasting technology and the vacuum roasting of this application. Sesame seeds are washed with water, added to an atmospheric pressure roasting pan, and roasted at 100-120℃ for 15-20 minutes to adjust the moisture content of the sesame seeds to 8%-10%. The pan is then heated to 180-210℃ and roasted for 10 minutes. After stopping heating, the temperature is rapidly reduced to 30-50℃ to complete the roasting process. Testing revealed that the atmospheric pressure roasted sesame seeds contained 23 core aroma pyrazine compounds with a total content of 67.8 mg / kg; 5 sulfur-containing compounds with a total content of 4.5 mg / kg; and methyl furfural at 3 mg / kg, exhibiting a burnt aroma.

[0028] By comparison, this application adopts low-temperature and normal-pressure pre-frying, which achieves the effect of adding water to adjust the quality and enhance the aroma; after low-temperature and normal-pressure pre-frying, vacuum high-temperature frying is carried out to produce a pure and rich aroma, while reducing the loss of flavor substances; this application can reduce the induction of excessive lipid oxidation, producing burnt, rancid and other off-odors, as well as carcinogenic substances such as benzo[a]pyrene.

[0029] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0030] Obviously, the embodiments described above are merely some embodiments of the present invention, not all embodiments. The accompanying drawings show preferred embodiments of the present invention, but do not limit the patent scope of the present invention. The present invention can be implemented in many different forms; rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the patent protection scope of this invention.

Claims

1. A method for roasting sesame seeds under vacuum conditions, characterized in that, Includes the following steps: S1: Wash the sesame seeds with water and roast them in a vacuum roasting pan. S2: Quickly create a vacuum to raise the temperature of the vacuum seed roasting pan and heat it to the roasting stage; S3: Stop heating and cool down under vacuum conditions to complete the stir-frying process.

2. The method for roasting sesame seeds under vacuum conditions according to claim 1, characterized in that, In S1, the roasting temperature range is 100-120℃, and the roasting time is 15-25 minutes.

3. The method for roasting sesame seeds under vacuum conditions according to claim 1, characterized in that, In S1, the moisture content of roasted sesame seeds is 8%-10%.

4. The method for roasting sesame seeds under vacuum conditions according to claim 1, characterized in that, In S2, a vacuum is rapidly pumped to between 0.03 and 0.04 MPa.

5. The method for roasting sesame seeds under vacuum conditions according to claim 1, characterized in that, In S2, a vacuum is rapidly drawn to a pressure between 0.05 and 0.06 MPa.

6. The method for roasting sesame seeds under vacuum conditions according to claim 1, characterized in that, In S2, a vacuum is rapidly pumped to between 0.07 and 0.08 MPa.

7. The method for roasting sesame seeds under vacuum conditions according to claim 1, characterized in that, In S2, the temperature of the vacuum seed roasting pan is increased to 180-210℃.

8. The method for roasting sesame seeds under vacuum conditions according to claim 1, characterized in that, In S2, the sesame seeds are roasted for 20-25 minutes.

9. The method for roasting sesame seeds under vacuum conditions according to claim 1, characterized in that, In S3, the temperature is lowered to 30-50℃ under vacuum conditions.

10. The method for roasting sesame seeds under vacuum conditions according to claim 1, characterized in that, In S1, the water washing is done by rinsing with running water for 3-5 minutes to remove dust from the surface of the sesame seeds.

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