Electron beam irradiation insecticidal method applied to starter propagation process

Abstract

The invention discloses an electron beam irradiation insecticidal method applied to a koji making process, and relates to the technical field of storage of Luzhou-flavor liquor koji. After the method is adopted for killing insects, the performance indexes are as follows: the live insect detection rate is 0, and the moisture content, acidity, saccharifying power, liquefying power, total bacterium number, fungus number and micro-ecological structure of the Luzhou-flavor liquor koji stored for 3 months after irradiation treatment are not changed, so that the Luzhou-flavor liquor koji can safely live in summer; the irradiated Luzhou-flavor liquor yeast can guarantee the micro-ecological and physicochemical properties of the yeast which is not irradiated after being stored for three months, and yeast pests in all stages in the yeast are killed.

Description

Technical Field

[0001] The invention relates to the technical field of Luzhou-flavor liquor Daqu storage, and in particular to an electron beam irradiation insecticide method applied to a koji making process. Background Art

[0002] After the fermentation and cultivation of Daqu, the koji industry has to go through a long period of stacking (storage), during which time, koji insects will eat the Daqu, and the saccharification and liquefaction power of the koji blocks will decrease, which will not only lead to a decline in the quality of Daqu, but also pollute the surrounding environment and cause ecological problems, especially during the summer storage period, the loss is as high as 30%. Traditional insecticide methods include chemical insecticides, radio frequency heating insecticides, atmosphere-controlled insecticides, and trapping lamp insecticides. Chemical insecticides can cause pests to develop drug resistance, and the residues can cause health hazards and have a negative impact on the environment. Radio frequency heating insecticides can cause stable changes, and temperature-sensitive foods cannot be used for this method. The atmosphere-controlled insecticide method is expensive and difficult to use for large-scale pest control. The insecticide efficiency of trapping lamps is not high, and can only guarantee an insecticide efficiency of 30-40%, which cannot fundamentally solve the problem.

[0003] Radiation has been approved in about 60 countries for use with up to 40 different foods to control microbial contamination, prevent sprouting or insect infestation. For decades, Canada has approved the irradiation of wheat and whole wheat flour to control insects, as well as the irradiation of dehydrated seasonings to control microorganisms. Electron beam irradiation is limited in its use in food due to its limited penetration, usually less than 5 cm, but simultaneous application on both sides can double the overall penetration rate. Daqu pests are a major problem, and there is an urgent need to strengthen technical research on the safety of Daqu during the summer to improve the quality of Daqu, while also improving the working environment of the staff, and also reducing the contamination of brewing raw materials by the spread of koji insects. For this reason, this application provides an electron beam irradiation pest control method applied to the koji making process. Summary of the invention

[0004] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0005] An electron beam irradiation pest control method applied to koji making process comprises the following steps:

[0006] S1. Pack the Luzhou-flavor liquor Daqu in a woven bag and place it flat on the irradiation tray, ensuring that each brick is placed flat and the total height does not exceed 6 cm;

[0007] S2. The irradiation tray is made of transparent glass, and a pair of irradiation sources are used and located at the upper and lower parts of the irradiation tray, and the placed samples are irradiated on both sides;

[0008] S3. Ensure that the cumulative irradiation dose is ≤1.40kGy and the number of irradiation times is 2 times.

[0010] Furthermore, the moisture content of the irradiated Daqu is controlled to be ≤12%.

[0011] Furthermore, the woven bag packaging is a nylon-polypropylene composite plastic bag.

[0012] Furthermore, the radiation source is a high-energy electron beam.

[0013] The beneficial effects of the present invention are as follows:

[0014] 1. The performance indicators of the present invention after killing insects by this method are: the detection rate of live insects is 0, and the moisture content, acidity, saccharification power, liquefaction power, total bacteria count, fungus count, and microecological structure of the Luzhou-flavor liquor Daqu stored for 3 months after irradiation treatment remain unchanged, so that the Luzhou-flavor liquor Daqu can safely survive the summer and meet the industry use standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a microecological community identification diagram of a sample of Daqu bacteria microecologically treated with irradiation at a dose of less than 1.40 kGy and stored for 90 days and a sample of a sample not treated with irradiation and stored for 90 days;

[0016] Figure 2 It is a microecological community identification diagram of a sample of the Daqu fungus microecological system irradiated with a dose of less than 3.55 kGy and stored for 90 days and a sample not irradiated and stored for 90 days;

[0017] Figure 3 It is a comparison table of the physical and chemical properties of the Daqu samples after irradiation treatment of the present invention. DETAILED DESCRIPTION

[0018] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0019] The present application provides an electron beam irradiation pest control method applied to the koji making process, and provides the following technical solutions, which will be described in detail below:

[0020] An electron beam irradiation pest control method applied to koji making process comprises the following steps:

[0021] S1. Pack the Luzhou-flavor liquor Daqu in a nylon-polypropylene composite plastic bag and place it flat on a glass irradiation tray, ensuring that each brick is placed flat and the total height does not exceed 6 cm;

[0022] S2. The irradiation source is a high-energy electron beam, and a pair of irradiation sources are used and located above and below the glass irradiation tray, and the placed samples are irradiated on both sides;

[0023] S3. Ensure that the cumulative irradiation dose is ≤1.40kGy, and the number of irradiations is 2 times, and control the moisture content of the irradiated Daqu to ≤12%.

[0024] Taking Luzhou-flavor liquor Daqu as an example, the performance indicators after using this method to kill insects are: the detection rate of live insects is 0, and the moisture content, acidity, saccharification power, liquefaction power, total bacteria count, fungi count, and microecological structure of Luzhou-flavor liquor Daqu after irradiation treatment and storage for 3 months remain unchanged, so that Luzhou-flavor liquor Daqu can safely spend the summer and meet the industry use standards (Luzhou-flavor liquor Daqu after irradiation can ensure that the microecology and physical and chemical properties of Daqu that have not been irradiated can be restored to those of Daqu that have not been irradiated after storage for three months and Daqu pests at all stages in Daqu can be killed);

[0025] The experimental basis of this method is: 0, 0.37, 1.40, 2.80, 3.10, and 3.55 kGy high-energy electron beam irradiation doses were selected for irradiation treatment of Daqu. Strict aseptic operation and storage were ensured to explore the effect of irradiation treatment on the original microorganisms of Daqu. Traditional cultivable technology and high-throughput Illumina-MiSeq sequencing methods were used to detect the composition and changes of microbial diversity in Daqu, and the effects of high-energy electron beam irradiation treatment on the microecology and physical and chemical properties of Daqu were explored.

[0026] Through physical and chemical properties and microbial testing, high-energy electron beam irradiation doses of 0, 0.18kGy, 0.27kGy, 0.50kGy and 1.4kGy were selected for irradiation treatment of Daqu, and the feasibility of high-energy electron beam irradiation of Daqu to kill insects was explored.

[0027] Experimental data

[0028] Through the traditional culturable counting method, it was found that after 40 days, the total number of Daqu samples, molds and yeasts after irradiation of 1.40 kGy or less could be restored to the level of samples without irradiation treatment, and the number of microorganisms could reach the same order of magnitude, and the microecological changes were shown in Table 1-2:

[0029] Table 1 Changes in the number of microorganisms of fungi and yeast at different irradiation doses and storage times

[0030]

[0031]

[0032] Table 2 Changes in the number of total bacteria at different irradiation doses and different storage times

[0033]

[0034] From the weighted UniFrac distance PCoA of bacterial and fungal communities analyzed by Illumina MiSeq sequence analysis, it can be seen that the microecology of Daqu bacteria treated with irradiation below 1.40kGy after 90 days of storage is similar to that of samples not treated with irradiation for 90 days, and the microecology of Daqu fungal microecology treated with irradiation below 3.55kGy after 90 days of storage is similar to that of samples not treated with irradiation for 90 days. In summary, irradiation below 1.4kGy will not have a significant impact on the microbial structure of Daqu. The results are as follows Figure 1 , Figure 2 Shown

[0035] Figure 1 , Figure 2 Weighted UniFrac distance PCoA of bacterial and fungal communities by Illumina MiSeq sequence analysis (Note: Point A in the figure represents samples irradiated with 0 kGy and not stored, points BG correspond to samples stored for 25 days after irradiation with 0 kGy, 0.37 kGy, 1.40 kGy, 2.80 kGy, 3.10 kGy, and 3.55 kGy, respectively; points HM correspond to samples stored for 60 days after irradiation with 0 kGy, 0.37 kGy, 1.40 kGy, 2.80 kGy, 3.10 kGy, and 3.55 kGy, respectively; points NS correspond to samples stored for 90 days after irradiation with 0 kGy, 0.37 kGy, 1.40 kGy, 2.80 kGy, 3.10 kGy, and 3.55 kGy, respectively).

[0036] Under irradiation treatment of 0kGy-3.55kGy, the moisture content in Daqu remained basically unchanged, and the acidity, saccharification power, liquefaction power and other enzyme activities fluctuated within the first 15 days after irradiation, and gradually returned to the non-irradiated level after 15 days. Irradiation has little effect on the physical and chemical properties, and after a storage period of 90 days, the physical and chemical properties of the Daqu samples after irradiation are slightly different from those of the Daqu samples without irradiation. The test results of physical and chemical property changes are as follows: Figure 3 ; and the changes in physical and chemical properties under different irradiation doses and different storage times (Note: WC is water content, TA is acidity, LP is liquefaction power, and DP is saccharification power).

[0037] At an irradiation dose of 0.18 kGy, no insects were found on the 60th day after irradiation, and very few koji worms were observed from 75 to 90 days. At 0.27 kGy and above, no insects were found on the 90th day after irradiation. However, koji worms were observed on the 30th day of the unirradiated Daqu samples, and the koji worms were rampant on the 60th day. This shows that after electron beam irradiation with a dose of 0.27 kGy or above, the insect pests in the Daqu blocks can be well suppressed, which can meet the purpose of killing insect pests. The insecticide test data is shown in Table 3, the environmental temperature record is shown in Table 4, and the koji worm observation on the 45th day is shown in Table 3:

[0038] Table 3 Effects of different irradiation doses on insect infestation during storage of Daqu

[0039]

[0040]

[0041] “-” not infested;

[0042] “+” means the insects start to grow, with a small number (less than 30 can be observed) of worms;

[0043] “++”: The worms can be clearly observed (the number of worms is between 30 and 100);

[0044] “+++” means that there are a large number of worms (100 to 300 worms);

[0045] "++++" There are too many beetles, and the beetle infestation is out of control (number of beetles) 300)

[0046] Table 4 Environmental temperature and humidity records

[0047]

[0048] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An electron beam irradiation pest control method applied to koji making process, characterized in that: The following steps are involved: S1. Pack the Luzhou-flavor liquor Daqu in a woven bag and place it flat on the irradiation tray, ensuring that each brick is placed flat and the total height does not exceed 6 cm; S2. The irradiation tray is made of transparent glass, and a pair of irradiation sources are used and located at the upper and lower parts of the irradiation tray, and the placed samples are irradiated on both sides; S3. Ensure that the cumulative irradiation dose is ≤1.40kGy and the number of irradiation times is 2 times.

2. The electron beam irradiation pest control method used in koji making process according to claim 1, characterized in that: Control the moisture content of irradiated Daqu to ≤12%.

3. The electron beam irradiation pest control method used in koji making process according to claim 1, characterized in that: The woven bag packaging is a nylon-polypropylene composite plastic bag.

4. The electron beam irradiation pest control method applied to koji making process according to claim 1, characterized in that: The radiation source is a high energy electron beam.

Images