阅读说明：本技术 一种鲜茧茧层的热处理方法 (Heat treatment method of fresh cocoon layer ) 是由 徐新雨 姜可欣 江文斌 谢乃钧 于 2021-10-20 设计创作，主要内容包括：本发明公开了一种鲜茧茧层的热处理方法。将结茧化蛹后的茧子,集中收购后,在24h内置干燥机中,平铺茧子重叠高度为45～65mm,50℃条件下停留时间为不超过50min；60℃条件下停留时间为不超过20min,得到茧层干燥而茧腔内的蛹保持活体状态的茧,经散热降温2～4h后,能直接进行选茧、煮茧工艺。本发明的鲜茧茧层的热处理方法,既能快速干燥茧层,又能保证蛹活且不出蛾,提高生丝品质及鲜蛹附加值,还能解决鲜茧无法短期保存的困境。(The invention discloses a heat treatment method of a fresh cocoon shell. After collectively purchasing cocoons after cocooning and pupation, flatly paving cocoons in a built-in drying machine for 24 hours, wherein the overlapping height of the cocoons is 45-65 mm, and the retention time at 50 ℃ is not more than 50 min; the retention time is not more than 20min at the temperature of 60 ℃, cocoons with dry cocoon shells and living pupas in cocoon cavities are obtained, and the cocoons can be directly subjected to cocoon selection and cocoon cooking processes after heat dissipation and temperature reduction for 2-4 h. The heat treatment method of the fresh cocoon shell can not only dry the cocoon shell quickly, but also ensure that the pupa is alive without producing moths, improve the raw silk quality and the fresh pupa additional value, and solve the dilemma that the fresh cocoon can not be stored in a short period.)

1. A heat treatment method of a fresh cocoon shell is characterized by comprising the following steps:

1) placing fresh cocoons after cocooning and pupation in a drying machine at the temperature of 50-60 ℃ for quick drying to obtain cocoons with dry cocoon shells and pupas in cocoon cavities in a living state;

2) placing the cocoon with the dried live pupa cocoon layer in a plastic frame with holes at the periphery, spreading and radiating heat at room temperature, then directly selecting cocoon, removing leftover cocoon which can not be reeled, vacuum permeating and absorbing water, and adding the selected cocoon into a cocoon cooking machine to cook the cocoon.

2. The process for heat-treating fresh cocoon shells as claimed in claim 1, wherein in step 1), said fresh cocoon shells are cocoon shells which are collected within 24 hours after collection.

3. The method for heat-treating fresh cocoon shells as claimed in claim 1, wherein in step 1), the overlapping height of spread cocoons in the drying machine is 45-65 mm, and the retention time at 50 ℃ is not more than 50 min; the retention time at 60 deg.C is not more than 20 min.

4. The method for heat-treating fresh cocoon shells as claimed in claim 1, wherein in step 2), heat is dissipated for 2-4 hours.

Technical Field

The invention relates to a fresh cocoon preservation method, in particular to a heat treatment method of a fresh cocoon shell.

Background

The silkworm cocoons are mainly used as raw silk after silk reeling, and are used as raw materials of silk products, fresh mulberry silkworm cocoons purchased from farmers contain more water, and living silkworm chrysalis in a cocoon cavity is transformed into moths after a plurality of days to fly out and damage cocoon layer cocoon silk, so that the conventional fresh silkworm cocoons are usually treated by adopting a high-temperature heating and pupa killing mode, and the purposes of drying the silkworm cocoons, killing pupa bodies and facilitating long-term storage are realized. The high-temperature heating drying pupa killing mode widely adopts a continuous hot air circulation heating mode to carry out high-temperature drying treatment on fresh cocoons for a long time, the temperature of the fresh cocoons which just enter a cocoon drying machine is generally 100-120 ℃, then the layering temperature is gradually reduced, the temperature of a cocoon outlet is 60-75 ℃, and the dry-suitable cocoons with fully dried cocoon shells and pupa bodies are obtained. The application time is 5-6h

In recent years, fresh silkworm cocoons are stored in a freezing fresh cocoon mode, and fresh pupas of fresh cocoons after silk reeling can be eaten. The silkworm cocoon is dried, the edible value of the dried silkworm cocoon is not high, and the silkworm cocoon is mainly used as an extract of feed or chemical raw materials; while the fresh pupa value of the frozen fresh cocoons is protected, the cocoon silk sericin of a cocoon layer is not dried, and the raw silk is usually reeled and produced only after vacuum infiltration by adopting a method without cocoon cooking, and the performance of reeling, cleaning, cleanness and the like of the raw silk is not as good as that of the raw silk reeled by dry cocoons.

Published literature also reports fresh cocoon preservation methods such as:

1. the patent document with publication number CN 101509150A and publication number 2009.08.19 discloses a method for pretreating fresh cocoons, which comprises the steps of transferring fresh cocoons purchased from a cocoon station into a conveyor belt before no moth is produced, bringing the fresh cocoons into the temperature of-2 ℃ to-4 ℃ through the conveyor belt, after 0.15 to 0.75 hour, bringing the cocoons into the temperature of-5 ℃ to-18 ℃ through the conveyor belt, after 2 to 48 hours of treatment, bringing the cocoons into the environmental temperature of 0 ℃ to 4 ℃ through the conveyor belt, and after 2 to 30 hours of natural balance, carrying out normal hot air drying or superheated steam drying process. The method utilizes dynamic freezing pretreatment, the pretreatment can be continuously carried out, after the pretreatment is carried out on the fresh cocoons, the silkworm chrysalis can be killed, the problem that the drying time of the silkworm cocoons is short is solved, the effects of improving the reelability and reducing the myriameter hanging of the silkworm cocoons are particularly realized, and the phenomenon that the inner layer cocoon layer is damaged due to the fact that the raw foot cocoons are heated to aggravate in the drying process of the silkworm cocoons can be reduced.

2. Publication number: CN 102965738A, published as 2013.03.13, discloses a fresh cocoon preservation method, placing the deactivated fresh cocoons in a six-side sealed tent, exhausting oxygen-enriched air in the tent, introducing carbon dioxide for circular air drying, absorbing water by a drying agent in a circular gas passage, adjusting the temperature in the tent to 10-25 ℃, performing circular drying treatment on the fresh cocoons in the tent, and reducing the water of pupas in the fresh cocoons to 15% after circular drying, wherein the invention not only enables the silk reeling process of the fresh cocoons to be smoothly performed, but also solves the problems of large energy consumption and air pollution in the traditional cocoon drying process, adopts a device, the drying agent and the carbon dioxide, has low cost and no pollution, and the carbon dioxide is recycled, so that the cost is greatly saved, and no preservative is added in the whole process, so that the silkworm pupas processing and recycling are guaranteed, the silk quality is not changed, and the reeling is more facilitated.

However, the inventor researches and discovers that in the published documents, the fresh cocoon treatment method is complex and time-consuming, and fresh pupae die in the treatment process, so that the higher nutritional value and economic benefit of the fresh pupae are reduced.

Disclosure of Invention

In order to overcome the defects that the existing fresh cocoons are not easy to store, the quality of the reeled raw silk is relatively poor, and the value of silkworm chrysalis is reduced by drying treatment, the invention aims to provide a fresh cocoon storage method, which can keep the living state of silkworm chrysalis in a cocoon cavity while drying a cocoon layer so as to improve the quality of the raw silk and the added value of the fresh silkworm chrysalis. Therefore, the invention adopts the following technical scheme:

a heat treatment method of a fresh cocoon shell is characterized by comprising the following steps:

1) placing fresh cocoons after cocooning and pupation in a drying machine at the temperature of 50-60 ℃ for quick drying to obtain cocoons with dry cocoon shells and pupas in cocoon cavities in a living state;

2) the cocoons with the dried live pupa cocoon layers from the drying machine are placed in a plastic frame with holes at the periphery, heat dissipation is carried out by paving at room temperature, then cocoon selection is directly carried out, the lower-leg cocoons which cannot be reeled are removed, the selected cocoons are added into a cocoon cooking machine for cocoon cooking after vacuum permeation and water absorption, the adhesive force among cocoon layers and silk is reduced, the cocoon unwinding is facilitated, and the silk reeling requirement is met.

Further, in step 1), the fresh cocoons refer to cocoons which are purchased in a centralized manner and are kept for a set time, and the time is generally controlled within 24 hours.

Further, in the step 1), in a drying machine, the overlapping height of spread cocoons is 45-65 mm, and the residence time at 50 ℃ is not more than 50 min; the retention time at 60 deg.C is not more than 20 min. After the cocoon shell is rapidly processed by the dryer, the drying rate of the cocoon shell is preferably controlled to be 96-98%, so that the subsequent process treatment is facilitated, and the survival rate of the pupa is not influenced, and the drying rate of the cocoon shell is calculated as shown in the formula (1):

further, in the step 2), heat dissipation is carried out for 2-4 hours.

The invention has the beneficial effects that:

1) the silkworm cocoons with the dried cocoon layers can be produced according to the existing reeling process requirements, sericin on the surfaces of the cocoon silks after cocoon cooking is fully swelled, the performances of cohesion, cleanness, cleanliness and the like of raw silks can be improved, and the quality of the cocoon silk reeling is consistent with that of the dry cocoon silk reeling obtained after the traditional cocoon drying.

2) The silkworm pupae can keep a living state in the cocoon cavity, and the fresh pupae have higher nutritional quality and development and utilization value than the dry pupae obtained by common heat treatment.

3) The preservation time of the fresh pupated cocoons is only 12-15 days generally, and after the silkworm moths break the cocoons, the values of the cocoon silks and the pupas are completely lost. The invention can dry cocoon layer quickly, ensure pupa to live and not to produce moth, is especially suitable for the area with suitable climatic conditions and capable of collecting silkworm cocoon for a plurality of periods in one year, and solves the problem that fresh cocoon can not be stored for a short period.

Detailed Description

The heat treatment method of the fresh cocoon shell comprises the following steps:

1) putting cocoons subjected to cocooning and pupation in a drying machine at the temperature within 24 hours of centralized acquisition, wherein the overlapping height of the flat cocoons is 45-65 mm, and the retention time at 50 ℃ is not more than 50min at most; the retention time at 60 deg.C is no more than 20min at most, and cocoon is obtained with dry cocoon layer and living pupa inside cocoon cavity.

2) Placing the cocoons with the dried live pupa cocoon layers in the drying machine in a plastic frame with holes at the periphery for heat dissipation and temperature reduction for 2-4 h, then directly selecting cocoons, removing leftover cocoons which cannot be subjected to silk reeling, adding the selected cocoons into a cocoon cooking machine for cocoon cooking after vacuum permeation and water absorption, and then carrying out silk reeling to reduce the adhesive force among cocoon layers and silk, so that the cocoon silk unwinding is facilitated, and the silk reeling requirement is met.

The invention will be described in further detail below with reference to the selection of different parameters and the results of a small sample test in each example.

The first embodiment is as follows:

spring cocoons which are pupated at Zhuang Kou of Zhejiang province are purchased in a centralized manner, 3 parts of cocoon samples with equal weight (same particle number and same weight) are selected, the particle number of each cocoon is 50 during the experiment, the cocoon is placed in a drying machine at the temperature of 50 ℃, the cocoon is treated for 10min, 20min, 30min, 40min and 50min respectively, the cut-open test is carried out, the number of the living pupas is recorded, the mass of the pupas is weighed, the moisture content of cocoon layers is measured, and the average values are respectively taken to obtain the results shown in the table 1. For comparison, fresh silkworm cocoons in the same batch are selected and placed in a plastic basket with openings at the periphery without any treatment, the silkworm cocoons are used as reference samples, 3 parts of cocoon samples with equal weight (the same weight and the same grain number) are selected from the reference samples for comparative analysis, normal phenomena of rotten cocoons, bad cocoons, dead cocoons and the like exist in the selected reference samples, the average rate of the living cocoons is 91.47%, and the moisture content of a cocoon layer is 8.94%. Under the condition of 50 ℃, the influence of drying treatment of the fresh cocoons for 10-40min on the survival state of the silkworm chrysalis is small, the live pupa rate when the fresh cocoons are kept, the change of the pupa body quality is not obvious, the change of the moisture content of the cocoon layer after heat treatment is obvious, and a good drying effect is achieved; at 50 ℃, the pupa rate of fresh cocoons after drying treatment for 50min begins to obviously decrease, and the maximum allowable time at the temperature cannot exceed 50 min.

TABLE 150 ℃ Effect of drying time on silkworm cocoon

In this embodiment, the calculation method of the live pupa rate is as shown in formula (2), the cocoon weight change rate is as shown in formula (3), the cocoon layer water content is as shown in formula (4), and the pupa mass change rate is as shown in formula (5).

Wherein, the average cocoon sample number in the formula (2) comprises all samples of rotten cocoons, bad cocoons, dead cocoons and the like contained in the batch of sample cocoons, and if double-cocoon exists, the pupa body number obtained by actual cutting is counted.

Example two:

spring cocoons which are pupated at Zhuang Kou of Zhejiang province are purchased in a centralized manner, 3 parts of cocoon samples with equal weight (same particle number and same weight) are selected, the particle number of each cocoon is 50 during the experiment, the cocoon samples are placed in a drying machine at the temperature of 60 ℃, the cocoon samples are processed for 10min, 20min, 30min, 40min and 50min respectively, the cut-open inspection is carried out, the number of the living pupas is recorded, the mass of the pupas is weighed, the moisture content of cocoon layers is measured, and the average values are respectively taken to obtain the results shown in the table 2. For comparison, fresh silkworm cocoons in the same batch are selected and placed in a plastic basket with openings at the periphery without any treatment, the silkworm cocoons are used as reference samples, 3 parts of cocoon samples with equal weight (the same weight and the same grain number) are selected from the reference samples for comparative analysis, normal phenomena of rotten cocoons, bad cocoons, dead cocoons and the like exist in the selected reference samples, the average rate of the living cocoons is 91.47%, and the moisture content of a cocoon layer is 8.94%. Under the condition of 60 ℃, the influence of the fresh cocoon drying treatment for 10-20min on the survival state of the silkworm chrysalis is small, the living chrysalis rate in the fresh cocoon state can be maintained, and the living chrysalis rate and the chrysalis body quality change obviously when the fresh cocoon is dried for more than 20 min. The moisture content of the cocoon layer is obviously changed after heat treatment, and a better drying effect is achieved. The calculation method of each index was the same as in example 1.

TABLE 260 ℃ Effect of drying time on silkworm cocoon

Example three:

spring cocoons which are pupated at Zhuang Kou of Zhejiang province are purchased in a centralized manner, 3 parts of cocoon samples with equal weight (same particle number and same weight) are selected, the particle number of each cocoon is 50 during the experiment, the cocoon samples are placed in a drying machine at the temperature of 70 ℃ and are treated for 10min, 20min and 30min respectively, cutting and inspection are carried out, the number of live pupas is recorded, the mass of the pupas is weighed, the moisture content of cocoon layers is measured, and the results shown in the table 3 are obtained by averaging respectively. For comparison, fresh silkworm cocoons in the same batch are selected and placed in a plastic basket with openings at the periphery without any treatment, the silkworm cocoons are used as reference samples, 3 parts of cocoon samples with equal weight (the same weight and the same grain number) are selected from the reference samples for comparative analysis, normal phenomena of rotten cocoons, bad cocoons, dead cocoons and the like exist in the selected reference samples, the average rate of the living cocoons is 91.47%, and the moisture content of a cocoon layer is 8.94%. Under the condition of 70 ℃, the drying time has obvious influence on the survival state of the silkworm chrysalis, when the fresh cocoons are dried for 10min or more, the survival rate of the silkworm chrysalis is suddenly reduced, and the survival rate is only 0% after 30min of treatment. The moisture content of the cocoon layer is obviously changed after heat treatment, and the drying effect is good. The calculation method of each index was the same as in example 1.

TABLE 370 ℃ Effect of drying time on silkworm cocoon

Example four:

spring cocoons which are pupated at Zhuang Kou of Zhejiang province are purchased in a centralized manner, 3 parts of cocoon samples with equal weight (same number and weight) are selected and placed in a drying machine at the temperature of 40 ℃, the cocoon samples are processed for 40min and 50min respectively, cut-open inspection is carried out, the number of live pupae is recorded, the mass of the pupae is weighed, the water content of a cocoon layer is measured, and the results shown in the table 4 are obtained by averaging respectively. For comparison, fresh silkworm cocoons in the same batch are selected and placed in a plastic basket with openings at the periphery without any treatment, the silkworm cocoons are used as reference samples, 3 parts of cocoon samples with equal weight (the same weight and the same grain number) are selected from the reference samples for comparative analysis, normal phenomena of rotten cocoons, bad cocoons, dead cocoons and the like exist in the selected reference samples, the average rate of the living cocoons is 91.47%, and the moisture content of a cocoon layer is 8.94%. Under the condition of 40 ℃, the length of the drying treatment time has no obvious influence on the survival state of the silkworm chrysalis, the change of the cocoon weight and the change of the pupa body quality. After the moisture content of the cocoon layer is subjected to heat treatment, the moisture content of the cocoon layer is increased compared with that of a fresh cocoon after the moisture in the pupa body is evaporated, the drying effect of the cocoon layer is not ideal, and the cocoon layer is not suitable for being used as the drying temperature. The calculation method of each index was the same as in example 1.

TABLE 440 ℃ Effect of drying time on silkworm cocoon

The heat treatment method for the cocoon shell of the fresh cocoon can realize quick drying of the cocoon shell and guarantee that the pupa can live without moth emergence after implementation and detection. The embodiments of the present invention were tested using different conditions to obtain: the retention time at 50 ℃ is not more than 50min at most; the retention time at 60 deg.C is no more than 20min at most, and cocoon is obtained with dry cocoon layer and living pupa inside cocoon cavity. The silkworm cocoons after drying treatment can be directly subjected to cocoon selection and cocoon cooking processes. At 40 ℃, the water content of the cocoon layer is increased compared with that of fresh cocoons after the water in the pupa body is evaporated, the drying effect is not ideal, and the drying temperature is not suitable for being used.

The above description is only an embodiment of the present invention, but the structural features of the present invention are not limited thereto, and any changes or modifications within the scope of the present invention by those skilled in the art are covered by the present invention.