A pine pollen drying and processing method for preventing odor generation

Abstract

The invention belongs to the technical field of food processing, and relates to a pine pollen drying processing method for preventing the generation of peculiar smell, comprising the following steps: 1) sieving; 2) mixing; 3) airflow instantaneous drying; 4) infrared drying; 5) packaging and storage. The invention does not add any additives, retains the original flavor and nutrients of the pine pollen as much as possible, is a drying method with low temperature, short time, and can accurately control the moisture content, and the moisture content of the pine pollen after drying can be accurately controlled at a level of 2-3wt%, so that the generation of peculiar smell is avoided by controlling the moisture, and the loss of active ingredients is avoided, the whole process has good drying effect, high production efficiency, and high product quality.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and in particular relates to a pine pollen drying processing method for preventing the generation of peculiar smell. Background Art

[0002] Pine pollen, also known as pine flower and pine yellow, refers to the dried pollen of Pinus massoniana, Pinus tabulaeformis or plants of the same genus in the Pinaceae family. It is the only pollen variety in the treasure house of Chinese medicine that can be used as both food and medicine. Dried pine pollen is a light yellow fine powder, in the form of uniform small round particles, light and easy to fly, smooth, not sinking in water, slightly fragrant, and greasy. Pine pollen is rich in nutrients, containing protein, polysaccharides, flavonoids, phytosterols, unsaturated fats, choline, coenzymes and other nutrients. It has many health benefits such as enhancing immune function, delaying aging, regulating metabolism, improving gastrointestinal function, anti-inflammatory and analgesic, and anti-fatigue.

[0003] Pine pollen is rich in lipids, especially unsaturated fats. Unsaturated fats are very easy to come into contact with lipase, air, etc. to undergo hydrolysis or oxidation reactions, causing lipid rancidity and oxidation, producing odors such as rancidity, thereby reducing the sensory quality and nutritional value of pine pollen and shortening the shelf life of the product. Lipid oxidation is one of the main reasons for the deterioration of pine pollen. The usual method of inhibiting oxidation and extending the shelf life of the product is to add antioxidants, such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tert-butylhydroquinone (TBHQ), etc., and the addition of such antioxidants affects the natural properties of the product, and long-term use may have an impact on the health of the body.

[0004] Traditional drying methods, such as hot air drying in an oven, often consume a lot of energy, take a long time, and have low efficiency. Long-term heating causes a large amount of active ingredients in pine pollen to be lost or deteriorate, affecting product quality. Studies have found that pine pollen treated with microwave drying is more likely to have a "rancid smell" due to fat oxidation during storage, which causes the quality of pine pollen to deteriorate during its shelf life. Therefore, how to choose a suitable drying method to strictly limit the moisture content of pine pollen to a reasonable range while retaining the active ingredients as much as possible, avoid the appearance of pine pollen odor during storage, and improve product quality is a new topic in the development of the pollen industry. Summary of the invention

[0005] The present invention aims at solving the above-mentioned deficiencies in the prior art and provides a pine pollen drying and processing method for preventing the generation of odor.

[0006] The specific technical solutions of the present invention are as follows:

[0007] A pine pollen drying and processing method for preventing the generation of odor comprises the following steps:

[0008] 1) Sieving: Sieve the pine pollen through a 80-100 mesh sieve to remove lumps, so as to facilitate airflow drying;

[0009] 2) Mixing: Mix the sieved pine pollen in an air flow mixer for 3-10 minutes with a compressed air pressure of 0.7-1.2 MPa to make the state and moisture of the pine pollen raw materials more consistent, so as to accurately control the drying parameters and achieve the target moisture content;

[0010] 3) Airflow instant drying: The mixed pine pollen is subjected to pulsed airflow instant drying to obtain preliminarily dried pine pollen;

[0011] 4) Infrared drying: drying the preliminarily dried pine pollen by medium and short wave infrared drying to obtain dried pine pollen;

[0012] 5) Packaging and storage: The dried pine pollen is packaged and stored; it is sealed in a plastic bag and a composite kraft paper bag and stored in a cool and dry warehouse with an ambient humidity of ≤65%.

[0013] The pine pollen drying processing method of the present invention is a drying method with low temperature, short time and accurate control of moisture content; the generation of odor is avoided by controlling the moisture content, and the loss of active ingredients is avoided as much as possible.

[0014] It is difficult to reduce the moisture content of pine pollen to the target moisture content by using a single airflow drying; if a second drying is performed, the energy consumption is large, and the moisture content after drying is difficult to control, and it is easy to make the moisture content after drying too high or too low. Infrared drying takes a long time, which has a great impact on the active ingredients therein. The instantaneous airflow drying technology first adopted by the present invention can reduce the moisture content of pine pollen to a lower level in a relatively short time, and then reduce the moisture content of pine pollen to the target level through medium and short wave infrared drying. Airflow drying has a short time and high efficiency; medium and short wave infrared rays have strong penetrating power, uniform drying, low energy consumption, and temperature and time can be precisely controlled; the two drying methods are organically combined to shorten the entire process time and reduce the temperature, and the moisture content can be precisely controlled, while the energy consumption is low, and the quality of the pine pollen does not change significantly, and the nutrients and active substances are retained to the greatest extent.

[0015] The drying processing method provided by the invention can prevent the generation of pine pollen odor, which is beneficial to prolonging the shelf life of the product.

[0016] Furthermore, in the step 3), the inlet air temperature of the pulsed airflow instantaneous drying treatment is 150-180°C, the feed rate is 30-70kg / hour, and the inlet air flow rate is 7-12m / s.

[0017] Furthermore, in the step 3), the moisture content of the pine pollen after the preliminary drying is controlled at 6-8wt%.

[0018] The instantaneous airflow drying technology adopted by the present invention has a short airflow drying time and high efficiency, and can reduce the moisture content of pine pollen to 6-8wt% within a short time of 2-4 seconds.

[0019] Furthermore, in the step 4), the wavelength of the medium- and short-wave infrared drying is 2-4 μm, the temperature is 70-85° C., the time is 5-8 min, the material thickness is 2-3 cm, and the radiation distance is 6-10 cm.

[0020] Furthermore, in the step 4), the moisture content of the dried pine pollen is controlled at 2-3 wt %.

[0021] The present invention can accurately control the moisture content of pine pollen to the level of 2-3wt% through medium and short wave infrared drying with strong penetration, uniform drying and low energy consumption.

[0022] The rancid smell of dried pine pollen is mainly caused by fat oxidation, which is closely related to water content. If the water content in food is not well controlled and the water activity is less than a certain value, the oxidation reaction is a free radical reaction, and the food has many opportunities to combine with oxygen and fat, and the oxidation rate is very fast. Food containing unsaturated fatty acids is also very easy to oxidize and become rancid when exposed to the air. However, when the water activity is greater than a certain value, the presence of water increases the fluidity of the catalyst and increases the rate of oil oxidation.

[0023] The present invention avoids the generation of odor by controlling the moisture content and avoids the loss of active ingredients as much as possible. The present invention controls the moisture content of the final dried pine pollen at a level of 2-3wt%, thereby well controlling the water activity, allowing the moisture in the food to hydrogen bond with the peroxide, slowing down the initial rate of peroxide decomposition; water can combine with trace amounts of metal ions to produce insoluble metal hydrates, causing them to lose their catalytic activity or reduce their catalytic activity; thereby reducing their auto-oxidation reaction and improving the quality stability of the pine pollen.

[0024] The pine pollen drying processing method of the present invention is a drying method with low temperature, short time and accurate control of moisture content, which avoids the generation of odor and the loss of active ingredients. The parameters of each step are studied and determined, which prevents the generation of pine pollen odor and is conducive to extending the shelf life of the product.

[0025] The beneficial effects of the present invention are:

[0026] The invention provides a pine pollen drying processing method for preventing the generation of peculiar smell, which does not add any additives, retains the original flavor and nutritional components of the pine pollen as much as possible, and the moisture content of the pine pollen after drying can be accurately controlled at a level of 2-3wt%, thereby better inhibiting the oxidation reaction of fat therein, preventing the pine pollen from generating peculiar smell during the shelf life, and the whole process has good drying effect, high production efficiency, and improved product quality. DETAILED DESCRIPTION

[0027] The principles and features of the present invention are described below in conjunction with embodiments. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0028] Embodiment 1:

[0029] A pine pollen drying and processing method for preventing the generation of odor comprises the following steps:

[0030] 1) Sieve: Sieve the pine pollen through an 80-mesh sieve to remove lumps;

[0031] 2) Mixing: Mix the sieved pine pollen in an air flow mixer for 5 minutes with a compressed air pressure of 0.7 MPa;

[0032] 3) Airflow instant drying: The mixed pine pollen is subjected to pipeline airflow instant drying to obtain preliminarily dried pine pollen, the air inlet temperature is 150°C, the feed rate is 30kg / hour, the air inlet flow rate is 7-8m / s, and the moisture content of the preliminarily dried pine pollen is 7.0wt%;

[0033] 4) Infrared drying: The preliminarily dried pine pollen is dried by medium- and short-wave infrared drying. The drying conditions are wavelength 2-4 μm, temperature 70° C., time 8 min, material thickness 2.5 cm, radiation distance 8 cm, and the moisture content of the dried pine pollen is 2.5 wt%;

[0034] 5) Packaging and storage: The dried pine pollen is sealed in a plastic bag and a composite kraft paper bag and stored in a cool and dry warehouse with an ambient humidity of ≤65%.

[0035] Embodiment 2:

[0036] A pine pollen drying and processing method for preventing the generation of odor comprises the following steps:

[0037] 1) Sieve: Sieve the pine pollen through an 80-mesh sieve to remove lumps;

[0038] 2) Mixing: Mix the sieved pine pollen in an air flow mixer for 5 minutes at a compressed air pressure of 1.0 MPa;

[0039] 3) Airflow instant drying: The mixed pine pollen is subjected to pipeline airflow instant drying to obtain preliminarily dried pine pollen, the air inlet temperature is 165°C, the feed rate is 50kg / hour, the air inlet flow rate is 9-10m / s, and the moisture content of the preliminarily dried pine pollen is 6.6wt%;

[0040] 4) Infrared drying: The preliminarily dried pine pollen is dried by medium- and short-wave infrared drying. The drying conditions are wavelength 2-4 μm, temperature 78° C., time 6.5 min, material thickness 2.5 cm, radiation distance 8 cm, and the moisture content of the dried pine pollen is 2.3 wt%;

[0041] 3) Packaging and storage: The dried pine pollen is sealed and packaged in a layer of plastic bag and a layer of composite kraft paper bag, and stored in a cool and dry warehouse with an ambient humidity of ≤65%.

[0042] Embodiment 3:

[0043] A pine pollen drying and processing method for preventing the generation of odor comprises the following steps:

[0044] 1) Sieve: Sieve the pine pollen through an 80-mesh sieve to remove lumps.

[0045] 2) Mixing: Mix the sieved pine pollen in an air flow mixer for 5 minutes at a compressed air pressure of 1.2 MPa.

[0046] 3) Airflow instant drying: The mixed pine pollen is subjected to pipeline airflow instant drying to obtain preliminarily dried pine pollen, the air inlet temperature is 180°C, the feed rate is 70kg / hour, the air inlet flow rate is 11-12m / s, and the moisture content of the preliminarily dried pine pollen is 7.3wt%;

[0047] 4) Infrared drying: The preliminarily dried pine pollen was dried by medium- and short-wave infrared drying. The drying conditions were wavelength 2-4 μm, temperature 85°C, time 5 min, material thickness 2.5 cm, radiation distance 8 cm, and the moisture content of the dried pine pollen was 2.2 wt%.

[0048] 5) Packaging and storage: The dried pine pollen is sealed in a plastic bag and a composite kraft paper bag and stored in a cool and dry warehouse with an ambient humidity of ≤65%.

[0049] Comparative Example 1:

[0050] A pine pollen drying and processing method comprises the following steps:

[0051] 1) Sieve and mix as in Example 1

[0052] 2) Blast drying: The mixed pine pollen is dried in an electric blast drying oven to obtain dried pine pollen at a temperature of 85°C for 3 hours. The moisture content of the dried pine pollen is 2.5wt%.

[0053] 3) Packaging and storage: The dried pine pollen is sealed and packaged in a layer of plastic bag and a layer of composite kraft paper bag, and stored in a cool and dry warehouse with an ambient humidity of ≤65%.

[0054] Comparative Example 2:

[0055] A pine pollen drying and processing method comprises the following steps:

[0056] 1) Sieve and mix as in Example 1

[0057] 2) Infrared drying: The mixed pine pollen was dried by medium- and short-wave infrared drying. The drying conditions were wavelength 2-4 μm, temperature 75°C, time 45 min, material thickness 2.5 cm, radiation distance 8 cm, and the moisture content of the dried pine pollen was 2.6 wt%.

[0058] 3) Packaging and storage: The dried pine pollen is sealed and packaged in a layer of plastic bag and a layer of composite kraft paper bag, and stored in a cool and dry warehouse with an ambient humidity of ≤65%.

[0059] The values ​​of the active ingredient representative index β-carotene in the dried pine pollen of Example 1-3 and Comparative Example 1-2 are shown in Table 1:

[0060] Table 1 Numerical table of β-carotene in pine pollen after drying in the embodiments and comparative examples

[0061] β-carotene content (mg / 100g) Example 1 8.92 Example 2 8.81 Example 3 8.76 Comparative Example 1 3.10 Comparative Example 2 5.21

[0062] We conducted a three-month stability sensory test on the pine pollen obtained in Examples 1-3 and Comparative Examples 1-2. The results are shown in Tables 2 to 6:

[0063] Table 2 Results of sensory testing of pine pollen stability obtained in Example 1

[0064]

[0065] Table 3 Results of sensory testing of pine pollen stability obtained in Example 2

[0066]

[0067] Table 4: Results of sensory testing of pine pollen stability obtained in Example 3

[0068]

[0069] Table 5 Comparative Example 1 Sensory Test Results of Pine Pollen Stability

[0070]

[0071] Table 6 Comparative Example 2 Sensory Test Results of Pine Pollen Stability

[0072]

[0073] Compared with comparative examples 1-2, the entire process of examples 1-3 of the present invention has a low temperature and a short time, and the moisture content can be accurately controlled at a level of 2-3wt% during the operation.

[0074] As can be seen from Table 1, the loss of β-carotene, a representative indicator of active ingredients, in the dried pine pollen of Comparative Example 1 is relatively large, the loss of β-carotene in the dried pine pollen of Comparative Example 2 is obvious, and the values ​​of β-carotene in the dried pine pollen of Examples 1-3 are significantly higher than those of Comparative Examples 1-2.

[0075] It can be seen from Tables 2 to 6 that the pine pollen obtained in Examples 1 to 3 retained the unique smell and taste of pine pollen and had no peculiar smell after being placed in a constant temperature and humidity chamber and under sunlight for 3 months, and the color and state did not change significantly; the pine pollen obtained in Comparative Example 1 became darker in color and had agglomeration, and had a peculiar smell (or a slight peculiar smell) after being placed in a constant temperature and humidity chamber and under sunlight for 3 months.

[0076] The pine pollen drying method of the present invention can effectively prevent the generation of pine pollen odor while minimizing the loss of active ingredients, and the effect is remarkable.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for drying pine pollen to prevent the generation of odor, characterized in that: The following steps are involved: 1) Sieve: Sieve the pine pollen through a 80-100 mesh sieve to remove lumps; 2) Mixing: Mix the sieved pine pollen in an air flow mixer for 3-10 minutes with compressed air pressure of 0.7-1.2MPa; 3) Airflow instant drying: The mixed pine pollen is subjected to pulsed airflow instant drying to obtain preliminarily dried pine pollen; the pulsed airflow instant drying process has an inlet air temperature of 150-180°C, a feed rate of 30-70kg / hour, and an inlet air flow rate of 7-12m / s; 4) Infrared drying: drying the preliminarily dried pine pollen by medium- and short-wave infrared drying to obtain dried pine pollen; the wavelength of the medium- and short-wave infrared drying is 2-4 μm, the temperature is 70-85°C, the time is 5-8 min, the material thickness is 2-3 cm, and the radiation distance is 6-10 cm; 5) Packaging and storage: Packaging and storage of dried pine pollen.

2. The pine pollen drying and processing method for preventing the generation of odor according to claim 1, characterized in that: In the step 3), the moisture content of the pine pollen after the preliminary drying is controlled at 6-8wt%.

3. The pine pollen drying and processing method for preventing odor generation according to claim 2, characterized in that: In the step 4), the moisture content of the dried pine pollen is controlled at 2-3 wt %.

4. The pine pollen drying and processing method for preventing odor generation according to claim 1, characterized in that: In the step 5), a layer of plastic bag and a layer of composite kraft paper bag are used for sealing packaging, and the product is stored in a cool and dry warehouse with an ambient humidity of ≤65%.

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