Crispy type tussah pupae pre-prepared food and method for preparing the same

Abstract

The application relates to a crisp type pre-conditioned food of tussah pupae and a preparation method thereof. The method is characterized in that fresh tussah pupae are used as raw materials, a series of processing technologies such as spraying and moisturizing of organic acid, temperature control, inorganic acid immersion and killing, microbial-enzymatic treatment of tussah pupae, pickling and baking are combined to prepare the crisp type pre-conditioned food of tussah pupae, the method is simple in operation, can change the permeability of the chitin shell of the tussah pupae, increase the migration rate of the seasoning, reduce the proportion of the burst plasma, and simultaneously reduce the oil oxidation caused by repeated baking treatment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of food processing, in particular to a crispy type pre-prepared silkworm chrysalis food and a preparation method thereof. BACKGROUND

[0002] Autheraea pernyi belongs to arthropod, insect class, lepidoptera, and is a special product in China. The annual output of Autheraea pernyi cocoon is about 100,000 tons, and the output of silkworm chrysalis is 80,000 tons, accounting for more than 90% of the world's total output. For many years, China has maintained the position of the world's largest silkworm producer. The Autheraea pernyi production areas in China are mainly distributed in Liaoning, Jilin, Heilongjiang, Shandong, Inner Mongolia and Henan provinces, and the largest breeding area is in Liaoning, accounting for about 60% of the total Autheraea pernyi production in China.

[0003] Autheraea pernyi is a complete metamorphosis insect, and the individual development goes through egg, larva, pupa and adult (moth) four morphologically and physiologically completely different development stages to complete its life cycle. The Autheraea pernyi pupa is a transitional stage of Autheraea pernyi larva to adult metamorphosis. After the Autheraea pernyi autumn silkworm spins cocoon, it passes through a long winter in the form of pupa. In order to continue the species and survive, the pupa accumulates rich nutrients, which has high nutritional and health care value. The results of modern nutrition research show that the Autheraea pernyi pupa contains rich protein, which accounts for about 52% of the dry weight, higher than chicken eggs and pork, and most of which is globulin and albumin, easy to be absorbed and utilized by the human body. The Autheraea pernyi pupa protein contains 18 kinds of amino acids, and the content of essential amino acids for human body is higher than that of pig, cow, sheep and other three major meat foods except phenylalanine. The proportion of amino acid composition is reasonable, close to the standard mode of protein and amino acid content recommended by WHO / FAD, and belongs to high-quality protein easy to absorb. The lipid composition in the Autheraea pernyi pupa accounts for 25%-30% of the dry weight, mainly composed of various unsaturated fatty acids, which has various physiological and health care effects. The nutrients in the Autheraea pernyi pupa mainly include carotene, VA, VB2, VC, VE and the like, and the mineral elements mainly include potassium, magnesium, copper, zinc and selenium, among which the contents of VB2, VC, VE and zinc and selenium are relatively high. In addition, the Autheraea pernyi pupa also contains active ingredients such as lysozyme, superoxide dismutase (SOD), phospholipid, nucleotide and androgen-like substances. The Autheraea pernyi pupa, which is a healthy food with high nutritional and medicinal value, is increasingly favored by consumers. In addition, the Autheraea pernyi pupa is large and delicious, and has been widely eaten as a delicacy.

[0004] The pupa of the oak silkworm is delicious, but it is not easy to process. The pupa of the oak silkworm is large and thick-skinned, and there are often problems such as insufficient flavor and sticky pot caused by explosion during cooking, which is mainly due to the following technical bottlenecks in the processing of the pupa of the oak silkworm: (1) The chitin shell makes it difficult to season, and the internal moisture of the pupa of the oak silkworm is not easy to evaporate, which leads to explosion and sticky pot, thereby causing problems such as long operation time, and the oil used for frying cannot be recycled; (2) Repeated baking-frying processing is easy to cause oxidation of nutritional components, resulting in poor flavor.

[0005] The nutritional value of the pupa of the oak silkworm at different development stages is different, and the temperature is closely related to the body development of the pupa of the oak silkworm. Most researchers mainly focus on the influence on breeding, for example, during the warm cocoon period, the body of the pupa of the oak silkworm undergoes extremely intense changes, in order to adapt to the needs of the adult stage, some tissues and organs dissociate, and some tissues and organs occur and form, among which the changes of the reproductive system, the digestive system, the nervous system and the fat body are significant. However, there are few studies on the changes of the substances in the pupa of the oak silkworm during this period and the processing characteristics of the pupa of the oak silkworm. SUMMARY

[0006] Therefore, it is necessary to provide a preparation method of a crispy type pupa of the oak silkworm pre-conditioned food, which is simple in operation, can reduce the explosion ratio, and also reduce the oxidation of nutritional components caused by repeated baking-frying processing, so that the pupa of the oak silkworm prepared by the method is more crispy and delicious.

[0007] The specific technical solutions are as follows:

[0008] The application provides a preparation method of a crispy type pupa of the oak silkworm pre-conditioned food, which comprises the following steps:

[0009] Pre-treatment: fresh and live pupa of the oak silkworm is incubated at 26-28°C for 24-144h, and then the temperature is lowered to 4-6°C for 36-48h, and after multiple cycles, the final accumulated temperature reaches 170-180°C, and during the incubation, an organic acid solution is sprayed on the pupa of the oak silkworm, and the indoor humidity for storing the pupa of the oak silkworm is maintained at 70-75%;

[0010] Inactivation: the pre-treated pupa of the oak silkworm is soaked in an inorganic acid solution to inactivate the pupa of the oak silkworm;

[0011] Microbial-enzymolysis treatment: the inactivated pupa of the oak silkworm is uniformly sprayed with a culture solution of intestinal microorganisms of the pupa of the oak silkworm, and after 2-4h, water and a compound enzyme are added for enzymolysis; wherein the compound enzyme comprises lysozyme, acid cellulase and acid protease;

[0012] Pickling: the microbe-enzyme treated pupa of the oak silkworm is pickled with pickling material, and the pickling material comprises mulberry leaf extract and salt; and

[0013] Baking-frying: the pickled pupa of the oak silkworm is repeatedly baked and fried to prepare a crispy type pupa of the oak silkworm pre-conditioned food.

[0014] The application also provides a crispy tussah pupa pre-prepared food prepared by the preparation method.

[0015] Compared with the prior art, the application has the following beneficial effects:

[0016] The application uses fresh tussah pupa as raw material, and a series of processing technologies such as organic acid spraying and moisturizing, temperature control, inorganic acid immersion and killing, tussah pupa microbial-enzymatic treatment, pickling and frying are used to prepare the crispy tussah pupa pre-prepared food. The method is simple to operate, can change the permeability of the chitin shell of the tussah pupa, increase the migration rate of the seasoning, reduce the proportion of the explosion plasma, and also reduce the oil oxidation caused by repeated frying treatment.

[0017] The tussah pupa prepared by the method is more crispy, has better taste and longer shelf life. DETAILED DESCRIPTION

[0018] In order to make the above-mentioned purposes, features and advantages of the application more obvious and easy to understand, the specific embodiments of the application are described in detail below. In the following description, a large number of specific details are set forth in order to fully understand the application. However, the application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the application, so the application is not limited by the specific embodiments disclosed below.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the application belongs. The terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit the application.

[0020] The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0021] As used herein, "% (w / w)" means mass percentage.

[0022] As used herein, the term "accumulated temperature" refers to the total of the temperature above the starting temperature, which can be expressed by the following formula: K=N×(T-T0), K represents the accumulated temperature, T is the temperature of the tussah pupa (℃), N is the holding time of the tussah pupa at T temperature (days, D), and T0 is the starting temperature (the minimum effective accumulated temperature) (the starting temperature of the tussah pupa is 8℃). For example, the warm cocoon temperature in Liaoning is 21℃, so the accumulated temperature under this condition is 13℃ per day. The effective accumulated temperature of pupation is about 225 degrees.

[0023] As used herein, the term "oxidative stability" refers to the ability of a substance to resist the effects of oxygen or other oxidizing agents without permanently changing its properties.

[0024] The present application changes the permeability of the outer shell of the tussah pup, and combines drying, frying and seasoning processes to obtain a processing method which is simple to operate and can maintain the appearance and shelf life of the tussah pup.

[0025] Therefore, an embodiment of the present application provides a preparation method of a crispy tussah pup pre-prepared food, which comprises the following steps (1)-(5):

[0026] In step (1), pretreatment: fresh tussah pup is incubated at 26-28°C for a certain period of time, and then incubated at 4-6°C for a certain period of time after cooling, and the final accumulated temperature reaches 170-180°C after multiple cycles. Organic acid is sprayed on the tussah pup during incubation, and the indoor humidity for storing the tussah pup is maintained at 70-75%. Through the process of accumulated temperature, the fresh tussah pup changes, and the permeability of the chitin shell of the tussah pup and the degree of combination of the pup shell and the content of the tussah pup are changed. Further, during the process of accumulated temperature, the spraying of organic acid can soften the chitin shell, and the organic acid can also enter the body through the joints of the tussah pup, change its physiological changes, and make it easier to process.

[0027] In one specific example, the number of cycles is 3. In a more specific example, the fresh tussah pup is incubated at 26-28°C for 120-144h, then incubated at 4-6°C for 48h after cooling, and then incubated at 26-28°C for 60-72h after further warming, and then incubated at 4-6°C for 48h after cooling, and then incubated at 26-28°C for 24-48h after further warming, so that the final accumulated temperature reaches 170-180°C.

[0028] In one specific example, the organic acid in the organic acid solution includes malic acid. Alternatively, the amount of malic acid is ≤15% of the weight of the organic acid solution.

[0029] In one specific example, the organic acid in the organic acid solution also includes other organic acids, such as citric acid and acetic acid. Malic acid is an organic acid essential for the human body and an ideal food additive with low calories. Appropriate amount of malic acid combined with lemon or acetic acid can present strong natural fruit flavor, which helps to improve the flavor of the tussah pup.

[0030] Alternatively, the organic acid in the organic acid solution is malic acid and acetic acid, and the molar ratio of acetic acid to malic acid is (8.5-9):(1-1.5).

[0031] Optionally, the organic acid in the organic acid solution is malic acid and citric acid, and a molar ratio of citric acid to malic acid is (8.5-9):(1-1.5).

[0032] Optionally, the organic acid in the organic acid solution is malic acid, citric acid and acetic acid, and a molar ratio of the sum of citric acid and acetic acid to malic acid is (8.5-9):(1-1.5).

[0033] Optionally, a concentration of the organic acid in the organic acid solution is 1 mol / L-2 mol / L.

[0034] Step (2), inactivation: the pretreated tussah pupae are soaked in the inorganic acid solution to inactivate the tussah pupae.

[0035] In one specific example, the inorganic acid in the inorganic acid solution includes phosphoric acid and hydrochloric acid, and a molar ratio of phosphoric acid to hydrochloric acid is 1:(1-2).

[0036] In one specific example, a concentration of the inorganic acid in the inorganic acid solution is 3 mol / L-4 mol / L.

[0037] Step (3), microbial-enzymatic treatment: the inactivated tussah pupae are uniformly sprayed with the intestinal microbial culture solution of the tussah pupae, and water and a compound enzyme are added for enzymolysis after 2-4 hours, wherein the compound enzyme includes lysozyme, acid cellulase and acid protease.

[0038] The microbial-enzymatic treatment causes the protein and other substances of the tussah pupae shell to be enzymolyzed, thereby changing the performance of the shell itself.

[0039] In one specific example, a temperature of the enzymolysis is 45°C-65°C, a pH of the enzymolysis is 4.0-5.5, and a time of the enzymolysis is 1-2 hours.

[0040] In one specific example, in the compound enzyme, a weight ratio of the lysozyme, the acid cellulase and the acid protease is (1-3):1:1.

[0041] Optionally, an enzyme activity of the lysozyme is 10000 U / g-12000 U / g, an enzyme activity of the acid cellulase is 80000 U / g-90000 U / g, and an enzyme activity of the acid protease is 65000 U / g-70000 U / g.

[0042] Optionally, a dosage of the compound enzyme is 0.2%-0.4% (w / w) of the tussah pupae.

[0043] In one specific example, a weight ratio of the tussah pupae to water is (2-3):(1-2).

[0044] In one specific example, the intestinal microorganism is derived from the intestines of a tussah pup within 1-2 days after pupation.

[0045] In one specific example, the intestinal microorganism includes cellulase-producing bacteria and amylase-producing bacteria.

[0046] In one specific example, the method for preparing the culture solution of the intestinal microorganism includes the following steps:

[0047] The intestines of five-year-old tussah pupae are removed, crushed, and then transferred to various liquid culture media for enrichment culture. The obtained enrichment solution is diluted and then inoculated on various solid culture media for culture. The amylase and cellulase inhibition zones are selected and expanded for culture to prepare the culture solution of the intestinal microorganism.

[0048] Optionally, the absorbance of the culture solution of the intestinal microorganism at 600 nm is between 0.6 and 0.8.

[0049] In one specific example, the liquid culture medium is a beef extract peptone culture medium (NA).

[0050] Optionally, the beef extract peptone culture medium includes 10-12 g of peptone, 5-6 g of beef extract, 5-6 g of NaCl, and 1000 mL of water.

[0051] In one specific example, the solid culture medium includes a cellulase solid culture medium and an amylase solid culture medium.

[0052] The cellulase solid culture medium includes 10-12 g of CMC-Na, 4-5 g of ammonium sulfate, 2-3 g of potassium dihydrogen phosphate, 0.5-1 g of magnesium sulfate heptahydrate, 0.5-1 g of sodium chloride, 1-1.5 g of peptone, 20-22 g of agar, and 1000 mL of distilled water. Sterilization is performed at 121°C for 20 min.

[0053] The step of selecting and expanding the amylase inhibition zone for culture includes the following steps: after the bacteria grow well, 0.1 g / L of Congo red is added for staining, followed by washing with 1 mol / L of sodium chloride. The transparent circle is observed, and the activity is confirmed. Then, the bacteria are transferred to a special liquid culture medium (10-12 g of peptone, 10-12 g of yeast powder, 10-12 g of CMC-Na, 5-6 g of NaCl, 1-2 g of KH2PO4, 1000 mL of water, and pH 7.0) for shake flask culture.

[0054] The amylase solid culture medium includes 2.5-3 g of soluble starch, 5-6 g of peptone, 2.5-3 g of ammonium sulfate, 3-4 g of potassium dihydrogen phosphate, 2.5-3 g of calcium chloride hexahydrate, 0.5-1 g of sodium chloride, 20-22 g of agar, and 1000 mL of distilled water. Sterilization is performed at 121°C for 20 min.

[0055] The steps of selecting the amylase with the inhibition zone and amplifying the culture: after the bacteria grow well, iodine solution is added for staining, and the transparent circle is observed to determine the activity, and then the bacteria are transferred to a special liquid culture medium (starch 10g~12g, beef extract 3g~4g, peptone 10g~12g, NaCl 5g~6g, water 1000mL) for shake flask culture.

[0056] Step (4), salting: the microbial-enzyme treated tussah pupae are salted with a salting material containing mulberry leaf extract and salt.

[0057] The mulberry leaf extract can be prepared according to a conventional extraction method or purchased commercially; the mulberry leaf extract in the salting material can increase the oxidative stability of the oil and fat of the product and reduce the influence of frying and storage on the stability of the oil and fat of the tussah pupae.

[0058] In a specific example, in the salting material, the mass percentage of the mulberry leaf extract is 1%~2%, and the mass percentage of the salt is 4%~6%.

[0059] Step (5), frying: the salted tussah pupae are repeatedly fried to prepare the crispy tussah pupae pre-prepared food. The purpose of repeated frying is to make the tussah pupae crispier and less hard.

[0060] In a specific example, the tussah pupae are coated with hot oil, first hot frying, hot oil frying, second hot frying, hot oil re-frying, and third hot frying to prepare the crispy tussah pupae pre-prepared food.

[0061] Optionally, the moisture content of the crispy tussah pupae pre-prepared food is 20%~30%.

[0062] Optionally, the oil temperature for frying is 200℃~230℃. Optionally, the time for hot oil frying and hot oil re-frying is not more than 1min. Optionally, the first hot frying is performed at a temperature of 120℃~130℃ for 10min~20min; the second hot frying is performed at a temperature of 95℃~100℃ for 10min~15min; and the third hot frying is performed at a temperature of 60℃~65℃ for 60min~90min.

[0063] An embodiment of the present application provides the crispy tussah pupae pre-prepared food prepared by any one of the preparation methods described above. The tussah pupae pre-prepared food has the significant characteristics of crispiness, delicious taste, convenience for eating, and high nutritional value. The tussah pupae as the pre-prepared food can be directly eaten after being fried in hot oil for 1min~2min, and is a kind of nutritious food with rich nutrition, delicious flavor, and convenience for eating.

[0064] The embodiments of the present application will be described in detail below with examples. It should be understood that these examples are only used to illustrate but not to limit the scope of the present application. The experimental methods in the following examples without specific conditions are preferred to refer to the instructions given in the present application, but also can be in accordance with the experimental manual or conventional conditions in the art, or according to the conditions suggested by the manufacturer, or in accordance with the experimental methods known in the art.

[0065] In the following specific examples, the measurement parameters of the raw material components may have slight deviations within the weighing accuracy range if not otherwise specified. The temperature and time parameters allow for acceptable deviations caused by the instrument testing accuracy or operating accuracy.

[0066] The lysozyme, acid cellulase and acid protease used in the following examples can be commercially purchased, and the activity unit contents of the lysozyme, acid cellulase and acid protease are 10000 U / g, 90000 U / g and 65000 U / g, respectively.

[0067] Example 1

[0068] The present example provides a preparation method of a crispy type pre-conditioned food of tussah pupae, comprising the following steps:

[0069] (1) Pretreatment: fresh and live tussah pupae are incubated at 28℃ for 120h, then cooled to 6℃ for 48h, continuously incubated at 28℃ for 60h, then cooled to 6℃ for 48h, and finally incubated at 28℃ for 24h, so that the final accumulated temperature reaches 170℃-180℃. During the incubation, the tussah pupae are sprayed with a mixture of citric acid and malic acid (1 mol / L) at a molar ratio of 9:1, and the indoor humidity for storing the tussah pupae is maintained at 70%-75%.

[0070] (2) Inorganic acid soaking and inactivation: the tussah pupae are soaked in a mixed solution of phosphoric acid and hydrochloric acid (molar ratio of phosphoric acid to hydrochloric acid is 1:1) at 3 mol / L for 10-20 min, then taken out and rinsed with about 1 times the volume of tap water twice for standby.

[0071] (3) Microbial-enzymatic treatment: the tussah pupae are first sprayed with the intestinal microbial culture solution of five-year-old tussah pupae, and then treated for 2h. After adding water (weight ratio of pupae to water is 2:1) and 0.2% of mixed enzymes (weight ratio of lysozyme, acid cellulase and acid protease is 1:1:1) equal to the weight of the tussah pupae, the tussah pupae are treated in a bubble washing machine at a temperature of 45℃ and a pH value of 4.0 for 1h, and then drained for standby.

[0072] The preparation method of the gut microbial culture solution of the silkworm is as follows: after the fifth instar silkworm is immersed in 75% ethanol for surface disinfection, the silkworm is moved into 2-3 times of sterile water for rinsing 2-3 times, the gut is taken out through sterile operation, the gut is crushed, and then the gut is moved into a liquid culture medium for enrichment culture.

[0073] The enrichment culture condition is as follows: 150 r / min, 28 DEG C culture for 48 h, and enrichment culture for 2 times. After the second enrichment solution is diluted by 10 times dilution, 0.2 mL of the second enrichment solution is coated on various solid culture media, and culture is carried out in a 28 DEG C incubator. The bacteria with the inhibition circle of cellulase and amylase are selected for amplification culture, and the gut microbial culture solution of the silkworm pupa is obtained.

[0074] The liquid culture medium is beef extract peptone culture medium (NA): 10.0 g of peptone, 5.0 g of beef extract, 5.0 g of NaCl, and 1000 mL of water.

[0075] The solid culture medium is as follows:

[0076] a. The cellulase solid culture medium: 10 g of CMC-Na (sodium carboxymethyl cellulose), 4 g of ammonium sulfate, 2 g of potassium dihydrogen phosphate, 0.5 g of magnesium sulfate heptahydrate, 0.5 g of sodium chloride, 1 g of peptone, 20 g of agar, and 1000 mL of distilled water. Sterilization is carried out at 121 DEG C for 20 min.

[0077] The step of selecting the bacteria with the inhibition circle of cellulase for amplification culture is as follows: after the bacteria grow well, 0.1 g / L of congo red is added for dyeing, then 1 mol / L of sodium chloride is added for washing, a transparent circle is observed, and the activity is determined, and then the bacteria are transferred into a special liquid culture medium (10 g of peptone, 10 g of yeast powder, 10 g of CMCNa, 5 g of NaCl, 1 g of KH2PO4, and 1000 mL of water, pH 7.0) for shake flask culture.

[0078] b. The amylase solid culture medium: 2.5 g of soluble starch, 5 g of peptone, 2.5 g of ammonium sulfate, 3 g of potassium dihydrogen phosphate, 2.5 g of calcium chloride hexahydrate, 0.5 g of sodium chloride, 20 g of agar, and 1000 mL of distilled water. Sterilization is carried out at 121 DEG C for 20 min.

[0079] The step of selecting the bacteria with the inhibition circle of amylase for amplification culture is as follows: after the bacteria grow well, iodine solution is added for dyeing, a transparent circle is observed, the activity is determined, and then the bacteria are transferred into a special liquid culture medium (10 g of starch, 3 g of beef extract, 10 g of peptone, 5 g of NaCl, and 1000 mL of water) for shake flask culture.

[0080] (4) pickling: adding a pickling solution (containing 1% (w / w) mulberry leaf extract and 4% (w / w) salt) for pickling for 30 min, and then draining for standby.

[0081] (5) Hot-oil frying: wrap hot oil-frying-fry-fry-fry, prepare crisp type tussah moth pupa pre-prepared food, cold storage or normal temperature cool storage.

[0082] Wherein, twice frying oil temperature is 200℃, time is not more than 1min; oil weight ratio is 2:1; three times hot frying conditions are as follows: temperature 130℃, time 15min, temperature 100℃, time 10min, temperature 65℃, time 60min, ensure that the final product moisture content is 20%-30%.

[0083] Further, in order to study the influence of different pickling time in step (4), the pickling time in step (4) is set to 0h, 0.5h, 1h, 2h respectively, and other steps are the same as above-mentioned embodiment 1, the salt ion migration rate in tussah moth pupa pickled for different time is detected, and the results are shown in Table 1.

[0084] Example 2

[0085] The embodiment provides a preparation method of crisp type tussah moth pupa pre-prepared food, comprising the following steps:

[0086] (1) Pretreatment: take fresh tussah moth pupa and store at 26℃ for 144h, then reduce the temperature to 4℃ for 48h, continue to increase the temperature to 26℃ for 72h, then reduce the temperature to 4℃ for 48h, continue to increase the temperature to 26℃ for 24h, and finally store at 170℃-180℃; during the storage, spray the tussah moth pupa with acetic acid and malic acid (1mol / L) with a molar ratio of 8.5:1.5 to keep the humidity of the tussah moth pupa at 70%-75%.

[0087] (2) Inorganic acid soaking and inactivation: put into a mixed solution of 4mol / L phosphoric acid and hydrochloric acid (the molar ratio of phosphoric acid to hydrochloric acid is 1:2) for 10min-20min, then take out to obtain killed tussah moth pupa, and then rinse twice with about 1 times the volume of tap water.

[0088] (3) Microbial-enzymatic treatment: first spray the tussah moth pupa with intestinal microbial culture solution of tussah moth pupae, and then after 3h, add water (the weight ratio of pupae to water is 3:2) and 0.4% mixed enzymes (the weight ratio of lysozyme, acid cellulase and acid protease is 3:1:1) to the tussah moth pupae, and then treat in a bubble cleaning machine under the conditions of 60℃ and pH 5.0 for 2h, and then drain and reserve.

[0089] Wherein, the preparation method of the intestinal microbial culture solution of tussah moth pupae is the same as that in embodiment 1.

[0090] (4) Pickling: add pickling solution (containing 2% (w / w) mulberry leaf extract and 6% (w / w) salt) for pickling for 30min, and then drain and reserve.

[0091] (5) Hot-air frying: hot oil-wrapped hot-air frying, hot-air frying, hot-air frying, and hot-air frying, to prepare a crispy type pre-prepared food of oak silkworm pupae, which is stored in cold storage or at room temperature.

[0092] Among them, the oil temperature for twice frying is 230°C, and the time is not more than 1 min; the weight ratio of oil to material is 2:1; the conditions of the three times of hot-air frying are as follows: temperature 120°C, time 20 min, temperature 100°C, time 10 min, and temperature 60°C, time 90 min, to ensure that the moisture content of the final product is 20-30%.

[0093] Comparative Example 1

[0094] The content of Example 1 is basically the same, except that steps (2) and (3) are missing.

[0095] Specifically, a preparation method of a crispy type pre-prepared food of oak silkworm pupae is provided, which comprises the following steps:

[0096] Pre-treatment: take fresh and live oak silkworm pupae and incubate at 28°C for 120 h, then cool to 6°C for 48 h, continue to incubate at 28°C for 60 h, then cool to 6°C for 48 h, continue to incubate at 28°C for 24 h, and finally the accumulated temperature reaches 170-180°C; during the incubation, spray the oak silkworm pupae with a molar ratio of 9:1 of citric acid and malic acid (1 mol / L), and keep the indoor humidity for storing the oak silkworm pupae at 70-75%.

[0097] Marinating: add marinating solution (containing 1% (w / w) mulberry leaf extract and 4% (w / w) salt) and marinate for 30 min, then drain and reserve.

[0098] Hot-air frying: hot oil-wrapped hot-air frying, hot-air frying, hot-air frying, and hot-air frying, to prepare a crispy type pre-prepared food of oak silkworm pupae, which is stored in cold storage or at room temperature.

[0099] Among them, the oil temperature for twice frying is 200°C, and the time is not more than 1 min; the weight ratio of oil to material is 2:1; the conditions of the three times of hot-air frying are as follows: temperature 130°C, time 15 min, temperature 100°C, time 10 min, and temperature 65°C, time 60 min, to ensure that the moisture content of the final product is 20-30%.

[0100] Comparative Example 2

[0101] The content of Example 1 is basically the same, except that steps (1) and (3) are missing.

[0102] Specifically, a preparation method of a crispy type pre-prepared food of oak silkworm pupae is provided, which comprises the following steps:

[0103] Inorganic acid soaking inactivation: the fresh and live tussah pupae are soaked in a mixed solution of phosphoric acid and hydrochloric acid (molar ratio of phosphoric acid to hydrochloric acid is 1:1) for 10 min to 20 min, taken out, rinsed with about 1 times volume of tap water, and then used for killing tussah pupae.

[0104] Pickling: adding a pickling solution (containing 1% (w / w) mulberry leaf extract and 4% (w / w) salt) for pickling for 30 min, and then draining and preparing for use.

[0105] Frying: hot oil-warming-frying-warming-repeated frying-warming, to prepare a crispy tussah pupae pre-prepared food, which is stored in cold storage or at room temperature in a cool place.

[0106] Among them, the oil temperature for twice frying is 200℃, and the time is not more than 1 min; the weight ratio of oil to material is 2:1; the conditions of the three times of warming are as follows: temperature 130℃, time 15 min, temperature 100℃, time 10 min, and temperature 65℃, time 60 min, to ensure that the final product has a moisture content of 20% to 30%.

[0107] Comparative Example 3

[0108] The content of Example 1 is basically the same, except that steps (1) and (2) are missing.

[0109] Specifically, a preparation method of a crispy tussah pupae pre-prepared food is provided, which comprises the following steps:

[0110] Microbial-enzymatic treatment: first, the tussah pupae are sprayed with a tussah gut microbial culture solution, and then treated for 2 h; then, water is added to the tussah pupae (weight ratio of pupae to water is 2:1), and then 0.2% of a mixed enzyme (weight ratio of lysozyme, acid cellulase and acid protease is 1:1:1) is added to the tussah pupae, and then the tussah pupae are treated in a bubble cleaning machine under the conditions of a temperature of 45℃ and a pH of 4.0 for 1 h, and then drained and prepared for use.

[0111] Among them, the preparation method of the tussah gut microbial culture solution is the same as that of Example 1.

[0112] Pickling: adding a pickling solution (containing 1% (w / w) mulberry leaf extract and 4% (w / w) salt) for pickling for 30 min, and then draining and preparing for use.

[0113] Frying: hot oil-warming-frying-warming-repeated frying-warming, to prepare a crispy tussah pupae pre-prepared food, which is stored in cold storage or at room temperature in a cool place.

[0114] Among them, the oil temperature is 200℃, and the time is not more than 1 min; the oil weight ratio is 2:1; the conditions of the third heat baking are as follows: temperature 130℃, time 15 min, temperature 100℃, time 10 min, and temperature 65℃, time 60 min, to ensure that the final product moisture content is 20%~30%.

[0115] Comparative Example 4

[0116] The fresh tussah pupae were added with 4% (w / w) salt solution for pickling, and the pickling time was set to 0 h, 0.5 h, 1 h and 2 h respectively. The pickled tussah pupae were drained, and were baked and fried according to the step (5) in Example 1 to ensure that the product moisture content was 20%~30%.

[0117] Comparative Example 5

[0118] The content of Example 1 was basically the same, except that the pickling solution in step (4) did not contain mulberry leaf extract.

[0119] Test

[0120] The burst ratio, salt ion migration rate (salt content in tussah pupae) and product oil oxidation index were determined, and the results are shown in Tables 1~4.

[0121] As can be seen from Table 1, compared with Comparative Example 4, the method of Example 1 promoted the migration of salt ions, making the tussah pupae more easily flavored.

[0122] Table 1 Influence of the method of Example 1 and Comparative Example 4 on the salt ion migration rate

[0123]

[0124] As can be seen from Table 2, compared with Comparative Examples 1~4, the burst ratio of the crisp tussah pupae prepared by the method of Example 1 was significantly reduced; and compared with Comparative Example 4, Comparative Examples 1~3 had no obvious improvement in burst ratio, indicating that the steps in Example 1 synergistically reduced the burst ratio of tussah pupae.

[0125] Table 2 Influence of the method of Example 1~2 and Comparative Examples 1~5 on the integrity of tussah pupae and the migration rate of salt ions

[0126]

[0127] As can be seen from Tables 3~4, compared with Comparative Example 5, the addition of mulberry leaf extract in the method of Example 1 can significantly reduce the acid value and peroxide value of the terminal product of tussah pupae, and the taste is better. It shows that the method of Example 1 can improve the oil oxidation stability of the terminal product tussah pupae.

[0128] Table 3 Effect of the method of Example 1 and Comparative Example 5 on the oxidative stability of the oil from the pupae of the tussock moth

[0129]

[0130] The peroxide value indicates the primary degree of oxidation of the fat and is an index for measuring the primary oxidation products of the fat. Hydroperoxide is a key product of the oxidative rancidity of the fat, and therefore, the peroxide value of the fat can indicate the degree of oxidative deterioration of the fat.

[0131] The acid value is one of the indexes indicating the degree of hydrolytic rancidity of the fat, and reflects the degree of hydrolysis of the fat due to light, heat or lipase. The oxidation and decomposition of the unsaturated fatty acids to form organic acids is the main cause of the increase in the acid value.

[0132] The TBA value is one of the most widely used indexes for evaluating the final degree of oxidation of the fat, and indicates the reaction of the secondary oxidation product malondialdehyde produced by the oxidation and decomposition of the unsaturated fatty acids in the fat with TBA.

[0133] Table 4 Sensory evaluation of the end products prepared in Example 1 and Comparative Example 5

[0134]

[0135] The technical features of the above-described embodiments can be combined in any manner. In order to make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, however, as long as the combinations of the technical features do not contradict each other, they should be considered to be within the scope of the present disclosure.

[0136] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that, for those skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the scope of the present application. Therefore, the scope of the patent of the present application should be subject to the appended claims, and the description can be used to explain the content of the claims.

Claims

1. A method for preparing a pre-cooked food of crisp type of silkworm pupae, characterized in that, The method comprises the following steps: Pre-treatment: fresh and live tussah pupae are incubated at 26-28°C for 24-144 hours, then cooled to 4-6°C for 36-48 hours, and subjected to multiple cycles to reach a final accumulated temperature of 170-180°C; an organic acid solution is sprayed on the tussah pupae during incubation to maintain the indoor humidity at 70-75%, the organic acid in the solution includes malic acid, and the organic acid also includes one or more of acetic acid and citric acid, the molar ratio of the sum of citric acid and acetic acid to malic acid is (8.5-9):(1-1.5); Inactivation: the pre-treated tussah pupae are soaked in an inorganic acid solution to inactivate the tussah pupae; Microbial-enzyme treatment: the inactivated tussah pupae are uniformly sprayed with a culture solution of intestinal microorganisms of tussah pupae, and water and a compound enzyme are added for enzymolysis after 2-4 hours; the compound enzyme includes lysozyme, acid cellulase and acid protease; the intestinal microorganisms include cellulase-producing bacteria and amylase-producing bacteria; the culture solution of the intestinal microorganisms is prepared by the following steps: The intestines of five-year-old tussah pupae are taken out, crushed, and then transferred into liquid culture media for enrichment culture, and the obtained enrichment solution is diluted and then coated on solid culture media for culture, and the bacteria inhibition circles of cellulase and amylase are selected for amplification culture to prepare the culture solution of the intestinal microorganisms; The liquid culture medium is beef extract peptone culture medium; The solid culture medium includes cellulase solid culture medium and amylase solid culture medium; In the compound enzyme, the weight ratio of lysozyme, acid cellulase and acid protease is (1-3):1:1; The amount of the compound enzyme is 0.2-0.4% of the weight of the tussah pupae; The temperature of enzymolysis is 45-65°C, the pH of enzymolysis is 4.0-5.5, and the time of enzymolysis is 1-2 hours; In the step of microbial-enzyme treatment, the weight ratio of the tussah pupae to water is (2-3):(1-2); Pickling: the microbial-enzyme treated tussah pupae are pickled with pickling materials containing mulberry leaf extract and salt; and Oven-frying: the pickled tussah pupae are repeatedly oven-fried to prepare crisp tussah pupae pre-prepared food.

2. The production method according to claim 1, characterized by, In the pre-treatment step, the number of cycles is 3.

3. The preparation method according to claim 2, characterized in that, Fresh and live tussah pupae are incubated at 26-28°C for 120-144 hours, then cooled to 4-6°C for 48 hours, then incubated at 26-28°C for 60-72 hours, then cooled to 4-6°C for 48 hours, and then incubated at 26-28°C for 24-48 hours to reach a final accumulated temperature of 170-180°C.

4. The production method according to any one of claims 1 to 3, characterized by, The organic acid solution meets one or more of the following conditions: (1) the amount of malic acid is ≤15% of the weight of the organic acid solution; (2) the concentration of the organic acid in the organic acid solution is 1-2 mol / L.

5. The preparation method according to any one of claims 1 to 3, characterized in that, The inorganic acid solution meets one or more of the following conditions: 1) the inorganic acid in the inorganic acid solution includes phosphoric acid and hydrochloric acid, and the molar ratio of the phosphoric acid to the hydrochloric acid is 1:(1-2). 2) the concentration of the inorganic acid in the inorganic acid solution is 3 mol / L ~ 4 mol / L.

6. The preparation method according to any one of claims 1 to 3, characterized in that, In the step of microbial-enzymatic treatment, the intestinal microorganism is derived from the intestine of five-year-old silkworm moth.

7. The method of any one of claims 1 to 3, wherein the method further comprises the step of: The pickling material contains 1%~2% (w / w) mulberry leaf extract and 4%~6% (w / w) salt. ​ 8. The method of any one of claims 1 to 3, wherein the method further comprises the step of: In the frying step, the crispy silkworm pupa pre-prepared food is prepared by first hot frying, hot oil frying, second hot frying, hot oil re-frying and third hot frying after the silkworm pupa is coated with hot oil. ​ 9. The production method according to claim 8, characterized by, One or more of the following conditions are met: (1) the moisture content of the crispy silkworm pupa pre-prepared food is 20%~30%; (2) the oil temperature is 200℃~230℃; (3) the time of hot oil frying and hot oil re-frying is not more than 1 min; (4) the first hot frying is at a temperature of 120℃~130℃ for 10 min ~ 20 min; (5) the second hot frying is at a temperature of 95℃~100℃ for 10 min~15 min; and the third hot frying is at a temperature of 60℃~65℃ for 60 min~90 min.

10. The crispy silkworm pupa pre-prepared food prepared by the preparation method of any one of claims 1~9.

Images