• International Journal of Industrial Entomology and Biomaterials
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• v.46 no.1
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• pp.9-15
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• 2023

Recently, a silkworm strain (tentatively named Sericinjam) producing 100% sericin cocoons has been studied in South Korea. In this preliminary study, the crystallinity, mechanical properties, and dissolution conditions of sericin from Sericinjam cocoons were examined. The Sericinjam cocoon could be dissolved in water at high temperature (120℃) and high pressure (HTHP method) in an autoclave and in a CaCl₂/H₂O/EtOH mixture (ternary solvent method), resulting in 82% and 97% dissolution after 30 min, respectively. The solution viscosity of the silk sericin formic acid (SSFA) solution obtained from sericin extracted using the ternary solvent method was higher than that obtained using the HTHP method; however, SSFA solutions obtained from sericin extracted from conventional Baekokjam cocoons yielded a higher solution viscosity. The crystallinity and breaking strength of the sericin film from Sericinjam cocoons were slightly lower, respectively, than those from Baekokjam cocoons. In contrast, the elongation at break of the Sericinjam sericin film obtained using the HTHP method was higher than that of the Baekokjam sericin film.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.501-519
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• 2003

Silk Sericin(SS) is a natural protein extracted from cocoon of bombix mori and shows moisturizing effect to the skin due to a number of hydroxyl groups in the structure. But its application to cosmetics is limited due to its poor solubility in water. In order to solve this drawback and expand its application to cosmetics, polyethyleneglycol(PEG) was conjugated with sericin by reacting activated polyethyleneglycol(ActPEG). Reaction site of sericin is tyrosine residue, which was determined by using $^1$H-NMR. Random coil structure of sericin was transformed to beta-sheet structure by conjugating polyethyleneglycol. It was confirmed that melting point of sericin-PEG conjugate was lowered compared to that of each sericin and PEG due to the interaction between sericin and PEG in crystalline structure. Self-assembled sericin-PEG nanoparticle was obtained by dialyzing with alcohol solution of sericin-PEG conjugate against water. The particle is spherical and has 200-400nm of size. The moisturizing ability of sericin-PEG nanoparticle was much higher than that of sericin itself. Incorporation of vitamin A into sericin-PEG nanoparticle was carried out by diafiltration method. The content of incorporated Vitamin A in sericin-PEG nanoparticle was 8.9 wt％. Releasing behaviour of vitamin A incorporated into nanoparticle was tested in phosphate buffer, pH 7.4 at 37$^{\circ}C$. and half-life of Vitamin A release was 43hrs. Sericin-PEG nanoparticle exhibited higher moisturing effect than sericin itself and distilled water, respectively. No toxicity and irritation were observed in animal tests. It can be expected that the self-assembled sericin-PEG nanoparticle can be developed for cosmetics.

• Journal of Sericultural and Entomological Science
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• v.44 no.2
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• pp.82-86
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• 2002

Silk sericin powder was prepared by mechanical treatment from culled-cocoon extract of Bombyx mori silkworm. The physical and structural characteristics of sericin powder were investigated by instrumental analysis. The solubility of sericin powder was decreased nearly half of sericin lyophilized. Amino acid analysis showed that arginine content was decreased from 3.72% to 0.03∼0.07%. XRD showed that molecules of sericin were somewhat regularly arranged by mechanical treatment. On the other hand, FT-IR showed the molecular vibration of silk sericin was not induced by mechanical treatment. Thermal properties also did not changed.

• Textile Coloration and Finishing
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• v.21 no.1
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• pp.38-45
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• 2009

First of all, the properties imparted to PET fabrics are resistance to and recovery from creasing or wrinkling when wet or dry; high resistance to stretch in the filament yarns but not in the staple; high abrasion resistance; good texture and appearance; resistance to heat ageing; good chemical resistance and good resistance, behind glass, to sunlight. But, the low moisture regain of PET fabric conduces to static troubles in textile processing. Furthermore, garments made from PET may, during wear, develop electric charges which attract to the fabric particles of soil(dirt, swarf, dust) flying in the air, so that the cuffs of shirts, for example, become soiled quickly and are not easily laundered clean. The sericin constitutes 25$\sim$30％ of silk protein and surrounds the fibroin fiber with sticky layer that supports the formation of a cocoon. The useful biochemical properties of sericin protein are oxidation resistant, antibacterial, UV resistant, hydrophilic property, and good affinity with hydrophobic material. These properties can be used as an improving reagent or a coating agent for natural and synthetic fibers, fabrics, and other intermediate products. The sericin is also applied to cross-link, and can be blended with other materials. In this study, we modified the surface of PET fabric by mixture of sericin finishing agent; sericin, polyuretane binder and 1,2,3,4-butanetetracarboxylic acid (BTCA) cross-link agent. Also, we investigated the finshing effect; moisture regain, stiffness, handle, drape and electrostatic. The moisture regain of PET fabric treated with sericin finishing agent was higher than that of untreated PET fabric. As a result of evaluating influence about handle of PET fabrics treated with sericin finishing agent, it was confirmed that the sericin finishing agent could be use as a linen like finishing agent.

• Journal of Sericultural and Entomological Science
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• v.13 no.1
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• pp.61-67
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• 1971

This experiment was conducted to know the effects of abnormal cocoons on the silk quality during the silk reeling process. The results obtained are summarized as follows: 1. The length, the width, the weight, the layer weight, and the layer ratio of abnormal cocoons are in every case 0.83∼4.65% less than those of normal cocoons. 2. The thickness of the abnormal cocoon layer is at)out 20.62∼22.4% less than that of the normal cocoon. 3. The sericin solubility of tile abnormal cocoon layer is about 11.75∼30% more than that of the normal cocoon layer. 4. The degumming ratio of the abnormal cocoon layer is about 6.51∼9.32% more than that of the normal cocoon layer. 5. The length of a have, the weight of a tave and percentage of raw silk yield of the abnormal cocoon are decreased 9.43%, 8.53% and 6.72% each as compared with those of the normal cocoon. 6. The percentage of reelability of abnormal cocoons is decreased 9.58％ as compared with that of normal cocoons. 7. The neatness of abnormal cocoons is 3 per cent lower than that of normal cocoons. 8. In the cleanness test of abnormal cocoons, the number of split ends i9 about 1.5∼3.8 times as much as that of normal cocoons. Especially cleanness of abnormal cocoons is 16,3 per cent lower than that of normal cocoons. 9. The number of non-reelable cocoons of abnormal cocoons is increased 1.4∼5.5 times as much as that of normal cocoons. In abnormal cocoon, the number of knot which resulted in the breaking of silk end is increased 1.9∼3.5 times as much as that in normal cocoon.

• Journal of Sericultural and Entomological Science
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• v.16 no.2
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• pp.77-98
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• 1974

This study was carried out ill an attempt to investigate the properties and activities of sericin obtained from silk cocoon shells in silk reeling water through various instrumental analyses. In addition, the effects of the characteristics in sericin solubility on the reeling process and silk qualities were also studied on the basis of tile above conditions. The results obtained are as follows： I. The sericin properties and activities through various analytical instruments. 1. The water solubility of each amino acid such as serine, glycine. glutamic and aspartic acids against the pH modified water by using automatic amino acid analyzer, showed the lowest solubility at PH 5, but it increased according to drifting toward the alkalinity. 2. When the obtained sericin particles by water pH variation were observed with the electronic microscope, it was found for the sericin Particles to expand in the alkaline regions. 3. The IR spectrum results showed the differences among the pH modified sericin solutions at the range of 2,100cm-1 and 1.890cm-1 of wave number. 4. The existence of sericin with in silk fabrics made differences in the X-ray interference intencity, that is, the non-degummed fabrics had the interference peak at 2$\theta$=14$^{\circ}$, 17$^{\circ}$, 24$^{\circ}$, and the degummed ones had it at 2$\theta$=17$^{\circ}$, 18$^{\circ}$, 20$^{\circ}$, 23$^{\circ}$, 26$^{\circ}$. II. The results of sericin solubility for silk reeling process. 1. The sericin solubility and swelling had a tendency to increase up with high M-alkalinity and pH value of water. But in case of acidity. water hardness and concentration of ethylene glycol were high, the sericin solubility and swelling were decreased. 2. With the filature experiments, the best conditions of filature orator are summarized as fellows ; a. pH; 6.9${\pm}$0.2 d. acidity; below10ppm b. total hardness; 55：5ppm e. Fe ion; none c. M-alkalinity; 40${\pm}$10ppm

• Journal of Sericultural and Entomological Science
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• v.10
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• pp.73-75
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• 1969

There are two fold aims in this experimental study. The aim is to investigate the bacteria which produce the high activity enzyme or the cocoon for utilization to the textile and the industry. The ether is to protect against the bacteria that damage silk protein during storage. The results are summarized as followes: 1. Among the isolated bacteria from the cocoon, No 4 strain had the high activity of the $\alpha$-amylase. But this strain had not been identified. The results of experiment is shown in the table II. 2. Among the isolated bacteria from the cocoon, No II strain had the high activity of the protease on substance of the casein. The results of the experiment is shown in the table II. 3. The bacteria which had the high activity of the degumming effect of the sericin, the part of the operation for 7 days was higher part of the operation for 3 days. The results of the experiment are indicated in Fig I and Fig II.

• Journal of Sericultural and Entomological Science
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• v.13 no.1
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• pp.49-59
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• 1971

This experiment was conducted, how making use of "Seracol 100", a kind of nonionic surface active reagent, during cocoon cooking and silk reeling process which is mainly used in Korea and developed by one of the authors since 1965. Main purpose of the experiment is to investigate the influence of the activity of the reelability aid reagent on various degree of hardness component and various salts which are contained in filature water being used by silk factories now. Specifically, it was tried to determine the effects of the reelability aid reagent added to each sample water of artificially differentiated the degree of hardness component upon sericin solubility. Some of the major findings are summarized as follows. 1. "Seracol 100", with below 5$^{\circ}$dH water, increased sericin solubility in each sample water, but above $10^{\circ}$dH the effect of it shows a significant relationship with the different degree of hardness component. Besides the component (MgCO$_3$)$_4$ㆍMg(OH)$_2$, generally, the higher the degree of hardness in the water, the less the amount of desolved sericin in the water showed. There is little or no difference between 1000 times diluted "Seracol 100" water and 2000 times diluted "Seracol 100" water in terms of sericin solubility. 2. The different kind of degree of hardness component shows a significant relationship with sericin solubility, In case use of "Seracol 100", Mg hardness component affected on the sericin solubility more than Ca hardness. But in the control, contrary to this, that is Ca hardness component did more than Mg hardness, 3. The different kind of salts in degree of hardness component show a significant relationship with sericin solubility. In the control water, nitrate is the greatest among salts affecting on sericin solubility, next chloride and sulfate are in order. In case of "Seracol 100" water, chloride is the least among salts, below $10^{\circ}$dH, next sulfate and nitrate are in order, and above 15$^{\circ}$dH, next nitrate and sulfate are in order. 4. In case of "Seracol 100" water, the more contained heavy metal salts (Fe, Al, Cu, Mn) in the water, the less sericin solubility showed. It is found that there is little or no difference among other salts in terms of sericin solubility. But alkaline metal salt remarkably increased sericin solubility. 5. In case of "Seracol 100" water, tinting of the water was affected by Ca salts more than by Mg salts. Among other salts, only Al and Fe affected on the tinting of the water, specifically, in view of the fact that "Seracol 100" water increase the tinting of Fe salt water, but decrease the tinting of raw silk. It is thought that "Seracol 100" deter Fe$^{+2}$ from absorbing to raw silk by deteriorating the activity of Fe$^{+2}$ . 6. "Seracol 100" have the effect on osmosis of the water, After treatment until 2hrs the osmosis of 1000 times diluted "Seracol 100" water is the greatest, next orders are 2000 times diluted "Seracol 100" and control. From 2 hrs to 6 hrs the osmosis of 2000 times diluted water is the greatest, next orders are 1000 times diluted water and control. After 6 hrs the osmosis of the water is the same order as above. 7. In view of tile fact that "Seracol 100" have the effect to control the degree of hardness during the treatment of cocoon layer in the water, it is thought that, in varying degree of hardness in the water, there is a significant relationship between "Seracol 100" and degree of hardness components in cocoon layer.

• Journal of Sericultural and Entomological Science
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• v.43 no.2
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• pp.109-115
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• 2001

Silk sericin protein was extracted by treatment with enzyme or NaOH solution from raw silk and culled-cocoon shell. The extracted sericin was characterized and examined the functional properties as well as subjective properties for its use as a soap and a body cleaner. The optimum extraction conditions on specimen are NaOH (0.02 wt.%) or enzyme, Flavourzyme 3% under N2 gas. Molecular weights of sericin was decreased by treatment with enzyme, Actinase, from 10,000-30,000 to 2,700-4,200. Sericin showed important bioactive properties, for instance, lowering effect on blood glucose and alcohol. Subjective test of sericin soap and body cleaner showed superior in washability, foamability, and skin hydration, etc., to commercial soap and body cleaner. Therefore, it is thought that silk sericin can be expected as the source of bioactive and skin-compatible materials.

• International Journal of Industrial Entomology and Biomaterials
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• v.11 no.1
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• pp.13-19
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• 2005

Biotechnological researches in Central Asian Research Institute of Sericulture were developed since 1981 when laboratory of artificial diets for mulberry silk­worm was created. The researches were directed not only to creation of accessible artificial diets (AD) for off-season mass rearing of economical beneficial insect and for industrialization of sericulture but also to obtaining of easy reproducible source of animal proteins, carbohydrates, lipids, enzymes, enzymes inhibitors and other metabolites - bioresource for manufacture of oriental medicine preparations. Space experiments with silkworms became possible with use of AD. These experiments used mulberry silkworm as high effective board test organism with outstanding developmental, reproductive and transgenic properties having impor­tant significance in future of cosmonautics. Introduction to practice of bioprotective and ecologically pure method of drying and sterilizing of green cocoons and by-products of silk manufacture allows to increase efficiency of cocoons reeling technology as well as to preserve nativity of biological active substances in mulberry silkworm pupae that is unachievable by traditional methods of raw material processing. New spheres of application of two important silk proteins - fibroin and sericin in medicine, cosmetics, for bio- and nanotechnology are opening with use of biotechnological approaches. At present the achievements and experience of R & D in these fields are used in creation of modern pests biocontrol agents. Schemes of efficient processing of cocoon raw material, by-products and wastes of sericulture and cocoon processing are devel- Institute of Physiology and Biophysics, Uzbek Academy of Sciences, I, Niyazov street, 700095, Tashkent, Uzbekistan. oped for obtaining of traditional and new consumer products.