CN-122004283-A - Tussah fresh-keeping method

CN122004283ACN 122004283 ACN122004283 ACN 122004283ACN-122004283-A

Abstract

The application provides a method for preserving tussah, which comprises the steps of S1 dividing a first group and a second group with different freezing response characteristics according to developmental biology characteristics of the tussah, wherein the freezing response characteristics are characterized by at least one parameter of tissue moisture content, methylene blue penetration depth and body wall elastic modulus, S2 respectively applying differential pretreatment to the first group and the second group to ensure that the difference of any characterization parameter of the first group and the second group is not more than a preset threshold value, S3 combining the two groups of tussah to freeze, cooling the first group from 0-1 ℃ to-10 ℃ at 0.8-1.2 ℃ per minute, cooling the second group from-10 ℃ to-30 ℃ at 0.45-0.55 ℃ per minute, cooling the third group from-30 ℃ to-45 ℃ at 1.8-2 ℃ per minute, vacuum packaging after S4 is frozen, and storing the second group at-45-40 ℃. The tussah fresh-keeping method of the application reduces juice loss and inhibits abnormal release of endogenous enzymes by maintaining the structural integrity of cells, better maintains nutritional ingredients in the long-term freezing process, and maintains the sensory characteristics of compact meat, uniform color and no peculiar smell.

Inventors

HAN BING
SHEN JINYU
DUAN YU
MA YANHUI
ZHAO SHIWEN
LI HONGDA
DONG YANGE
LI XISHENG

Assignees

辽宁省蚕业科学研究所

Dates

Publication Date: 20260512
Application Date: 20260212

Claims (10)

1. The tussah fresh-keeping method is characterized by comprising the following steps of: s1, dividing tussah into a first group and a second group with different freezing response characteristics according to the developmental biological characteristics of the tussah, wherein the freezing response characteristics are defined as the degree of damage of ice crystals to cell tissue structures of the tussah under the same freezing condition, and are characterized by at least one parameter of tissue moisture content, methylene blue penetration depth and body wall elastic modulus; s2, respectively applying differential pretreatment to the first group and the second group, so that the difference of the first group and the second group on any characterization parameter does not exceed a preset threshold value; s3, combining the two groups of tussah silkworms subjected to the differentiation pretreatment, and freezing by adopting the same three-stage gradient freezing program, wherein, A first cooling stage, namely cooling from 0-1 ℃ to-10 ℃ at a cooling rate of 0.8-1.2 ℃ per minute; A second cooling stage, namely cooling from-10 ℃ to-30 ℃ at a cooling rate of 0.45-0.55 ℃ per minute; A third cooling stage, namely cooling from-30 ℃ to-45 ℃ at a cooling rate of 1.8-2 ℃ per minute; And S4, after the freezing is finished, vacuum packaging is carried out, and the products are stored at-45 to-40 ℃.
2. The method for keeping tussah fresh according to claim 1, wherein, The freeze response characteristic of the first set is higher than the second set; The pretreatment of the first group comprises the steps of air-drying for 8-12 min in an environment of 2-4 ℃, and then soaking in a first fresh-keeping liquid with pH of 5.0-5.5 for 10-20 min at 2-4 ℃; The second group of pretreatment comprises the steps of wetting with 0.3-0.7% citric acid solution in an environment of 2-5 ℃ and then soaking in a second fresh-keeping solution with pH of 4.0-4.5 for 25-35 min at 2-5 ℃; the first fresh-keeping liquid comprises, by weight, 0.15-0.25 part of chitosan, 0.08-0.12 part of tea polyphenol, 0.03-0.06 part of ascorbic acid and 100 parts of sterile water; the second fresh-keeping liquid comprises, by weight, 0.05-0.12 part of chitosan, 0.12-0.18 part of tea polyphenol, 0.05-0.07 part of ascorbic acid, 0.02-0.04 part of citric acid and 100 parts of sterile water.
3. The method for keeping tussah fresh according to claim 2, wherein the step S1 is preceded by a standardized pretreatment: Selecting fresh tussah, flushing with sterile water at 3-5 ℃, and draining off water on the surface of the fresh tussah; And (3) pre-cooling the drained tussah in an environment of-2 ℃ for 30-60 min, so that the surface temperature of the tussah is reduced to 0-1 ℃.
4. The method for keeping tussah fresh according to claim 1, wherein said preset threshold value satisfies at least one of: the absolute value of the tissue water content difference value of the two groups of tussah silkworms is less than or equal to 3 percent; the absolute value of the difference value of the methylene blue penetration depths of the two groups of tussah silkworms is less than or equal to 20 mu m; the absolute value of the difference value of the body wall elastic modulus of the two groups of tussah silkworms is less than or equal to 0.05 MPa.
5. The method for keeping tussah fresh according to claim 1, wherein said three-stage gradient freezing process further comprises: After the first cooling stage is cooled to-10 ℃, preserving heat for 20-40 min at-10 ℃; After the second cooling stage is cooled to-30 ℃, preserving heat for 45-75 min at-30 ℃; And after the third cooling stage is cooled to-45 ℃, preserving heat for 75-105 min at-45 ℃.
6. The method for keeping tussah fresh according to claim 1, wherein said step S1 is preceded by the further steps of: Collecting a plurality of tussah samples, and determining the developmental biological characteristics of each tussah sample and the corresponding characteristic parameters of the freezing response characteristic, wherein the developmental biological characteristics comprise body length, head shell width and body wall transmittance, and the characteristic parameters of the freezing response characteristic comprise tissue moisture content, methylene blue penetration depth and body wall elastic modulus; and based on the measured data, establishing a mapping relation between the developmental biological characteristics and the characteristic parameters of the freezing response characteristics to obtain a prediction model, wherein the prediction model is used for predicting the freezing response characteristics of the tussah to be divided according to the developmental biological characteristics of the tussah to be divided, and dividing the tussah to be divided into the first group or the second group according to the prediction model.
7. The method for keeping tussah fresh according to claim 6, wherein said step S1 comprises: Measuring the body length, the head shell width and the body wall light transmittance of the tussah to be divided; Predicting the tissue water content, methylene blue penetration depth and body wall elastic modulus of the tussah to be divided by using the prediction model; If the predicted value meets any one of the following conditions that the tissue water content is more than or equal to 84%, the methylene blue penetration depth is more than or equal to 150 mu m and the body wall elastic modulus is less than or equal to 0.25 MPa, determining that the freezing response characteristic is high, and dividing the first group; Otherwise, determining that the freezing response characteristic is low, and dividing the freezing response characteristic into the second group.
8. The method for keeping tussah fresh according to claim 1, wherein, Before the step S1 and before the differential pretreatment for 6-12 hours, placing tussah in a closed environment, and introducing a gas mixture for fumigation treatment; The gas mixture contains methyl jasmonate or salicylic acid, the volume concentration of the methyl jasmonate or the salicylic acid is 10-50 ppm, the fumigation treatment temperature is 15-25 ℃, and the fumigation treatment time is 1-2 h.
9. The method for keeping tussah fresh according to claim 1, wherein, The vacuum packaging is carried out in an environment of not more than-10 ℃.
10. The method for keeping tussah fresh according to claim 1, wherein after step S4 is completed and before eating, further comprising the step of adopting three-stage gradient rewarming: A first rewarming stage, namely heating from-45 to-40 ℃ to-1 ℃ at a heating rate of 0.8-1.2 ℃ per minute, and preserving heat at-1 ℃ for 25-35 min; A second re-heating stage, namely heating from-1 ℃ to 4 ℃ at a heating rate of 0.05-0.1 ℃ per minute, and preserving heat for 45-55 min at the temperature of 4 ℃; And in the third re-heating stage, heating from 4 ℃ to 12 ℃ at a heating rate of 0.3-0.6 ℃ per minute, and preserving heat at 12 ℃ for 10-15 min.

Description

Tussah fresh-keeping method Technical Field The application relates to the technical field of food preservation, in particular to a tussah preservation method. Background Tussah larvae are a special insect resource with high protein, low fat, high content of essential amino acids of human body and rich multiple mineral substances. The crude protein content of tussah 5-instar larvae in a fresh state can reach more than 28 g/100g, the total amino acid content exceeds 25 g/100g, and the content of fat is extremely low, so that the tussah 5-instar larvae are excellent edible insects with high nutritive value. In recent years, along with large-scale popularization of new feed resources of tussah, namely, artemia salix in western Liaoning, eastern inner Mongolia and other areas, the annual output of 5-year larvae of tussah is continuously increased. However, the harvesting of the tussah 5-year larvae is highly concentrated around 9 months each year, physiological metabolism is vigorous after harvesting, and the shelf life is less than 48 hours at normal temperature, so that the cross-regional circulation and peak shifting sales capacity of the tussah 5-year larvae are severely restricted. In the prior art, a quick-freezing process is adopted to freeze the tussah 5-instar larvae, namely, the picked tussah 5-instar larvae are directly placed into freezing equipment at-18 to-22 ℃ for one-time freezing after being simply cleaned and drained, and then are transferred into a refrigeration house with the same temperature for storage. The method is simple and convenient to operate, but the cooling process is lack of precise control, and ice crystals with large size and uneven distribution are easily formed in tissues in the freezing process, so that cell membranes and tissue structures are seriously damaged, and the loss of juice after thawing is obviously caused, nutrient components (such as protein and amino acid) are rapidly degraded, the risk of microorganism breeding is increased, and the sensory quality (including meat quality, color and flavor) is obviously deteriorated. The practical shelf life of the method is usually not more than 3 months, and the requirements of long-term storage and high-quality fresh-keeping are difficult to meet due to the restrictions of the factors. Therefore, the conventional freezing and fresh-keeping technology for tussah larvae is difficult to realize long-term (more than 12 months) freezing and storage, and meanwhile, the cell structural integrity of the tussah is effectively maintained, so that the loss of nutrient components, the increase of microbial safety risks and the deterioration of sensory quality and taste are caused, and the value is reduced. Disclosure of Invention The embodiment of the application aims to provide a method for preserving tussah so as to effectively maintain the cell structural integrity of the tussah while realizing long-term (more than 12 months) freezing and storage, and further ensure the nutrient content retention rate, microbial safety and sensory quality of the tussah. In order to solve the technical problems, the embodiment of the application provides the following technical scheme: the first aspect of the application provides a tussah fresh-keeping method, which comprises the following steps: s1, dividing tussah into a first group and a second group with different freezing response characteristics according to the developmental biological characteristics of the tussah, wherein the freezing response characteristics are defined as the degree of damage of ice crystals to cell tissue structures of the tussah under the same freezing condition, and are characterized by at least one parameter of tissue moisture content, methylene blue penetration depth and body wall elastic modulus; s2, respectively applying differential pretreatment to the first group and the second group, so that the difference of the first group and the second group on any characterization parameter does not exceed a preset threshold value; s3, combining the two groups of tussah silkworms subjected to the differentiation pretreatment, and freezing by adopting the same three-stage gradient freezing program, wherein, A first cooling stage, namely cooling from 0-1 ℃ to-10 ℃ at a cooling rate of 0.8-1.2 ℃ per minute; A second cooling stage, namely cooling from-10 ℃ to-30 ℃ at a cooling rate of 0.45-0.55 ℃ per minute; A third cooling stage, namely cooling from-30 ℃ to-45 ℃ at a cooling rate of 1.8-2 ℃ per minute; And S4, after the freezing is finished, vacuum packaging is carried out, and the products are stored at-45 to-40 ℃. In some variations of the first aspect of the present application, the freeze response characteristics of the first set are higher than the second set; The pretreatment of the first group comprises the steps of air-drying for 8-12 min in an environment of 2-4 ℃, and then soaking in a first fresh-keeping liquid with pH of 5.0-5.5 for 10-20 min at 2-4 ℃; The second gr