• Journal of Sericultural and Entomological Science
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• v.41 no.3
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• pp.196-200
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• 1999

The flat-ways spinned cocoon was prepared from the silkworm using flat and circular type cocooning frame. The spinning rate of the silkworm was 76.9% compared to the normal mounted silkworm. The arrangement of cocoon baves of the flat-ways spinned cocoon was more linear than the normal cocoon which is curved. To maintain the size-stability of the flat-ways spinned cocoon, degumming process was treated with enzymes. These flat-ways spinned cocoons could be used as padding materials for the thermal insulations and decoration uses for the traditional fan which the silkworms are mounted directly on the fan frame.

• 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.45 no.1
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• pp.46-57
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• 2003

This study was carried out to investigate the characteristics of the soluble sericins after degumming and after hydrolysis of insoluble sericin with various enzymes. Especially, the hydrolysis characteristics were examined in terms of molecular weight of the soluble sericin. Amino acid composition and molecular weight characteristics of the soluble sericins were also studied. When the insoluble sericin was hydrolyzed with kojizyme and flavourzyme, the solubility was highest at pH 7 and 50$^{\circ}C$. On the other hand, in the cases of protamex and alcalase, the highest solubility was obtained at 60$^{\circ}C$. In these cases, solubility increased with pH. In enzymatic hydrolysis, the solubility was increased with concentration of enzymes until 4 hours. After then, a slight difference was found along with treatment times. In enzymatic hydrolysis, the absorbance of the soluble sericin was increased with concentration of enzymes and treatment times. Average degree of polymerization was decreased with treatment time and concentration. The amino acid compositions were similar in low(low molecular weight by degumming) and high (high molecular weight by degumming). Those of PK (soluble sericin hydrolyzed with kojizyme), PP (soluble sericin hydrolyzed with protamex), and PA(soluble sericin hydrolyzed with alcalase) were similar to each other. Serine and tyrosine compositions were higher in low and high than those of PK, PP, and PA. However proline was absent in low and high. Molecular weights of the various sericins became higher as KP>high>PP>low>PA and those of KP and PA were 9,800 and 905 respectively.

• Membrane Journal
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• v.17 no.4
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• pp.375-380
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• 2007

To recover sericin protein from by-product in silk production process, a polyethersulfone hollow fiber ultra-filtration membrane module was used. The soap in the degummed solution was precipitated by calcium chloride. The influence of membrane module of submerged and external type on membrane fouling was investigated. The effect of soap and protein on the membrane fouling in the external type membrane module was also studied. The removal of soap resulted in decreasing the membrane fouling. It was shown that the protein and the membrane were affected by the soap.

• Textile Coloration and Finishing
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• v.22 no.2
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• pp.132-139
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• 2010

Sericin pulverization process was applied by freezing-thawing of sericin protein concentration solution and physicochemical properties of sericin/chitosan blended films were investigated. In sericin pulverization process by freezing-thawing method, the refrigeration storage at $4^{\circ}C$ maximized gelling between sericin molecules, which increased 10% of recovery ratio from sericin concentration solution that using ultrafiltration procedure. In physicochemical properties of sericin/chitosan blended films, the maximum load of chitosan (6.7kgf) had higher than that of sericin (1.2kgf), and the elongation of sericin and chitosan had 96% and 34%, respectively. Also FT-IR analysis of sericin/chitosan blended films showed that both sericin and chitosan films had amide I peak (N-H bond) in $1,521cm^{-1}$ and amide II peak (C=O bond) in $1,630cm^{-1}$. In addition, it could confirm compatibility between both materials as indicated by the decrease in the amide I peak's absorption value as chitosan content increases.

• Journal of Sericultural and Entomological Science
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• v.45 no.1
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• pp.58-65
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• 2003

This study was carried out to investigate the characteristics of the soluble sericins after degumming and after hydrolysis of insoluble sericin with various enzymes. Physical and chemical characteristics of the soluble sericins were also studied and pack test was conducted. Electro donating ability of the various sericins became higher as high＞low＞KP＞PP＞PA. In FT-IR analysis, the band of insoluble sericin at 3,285cm$\^$-1/ was shifted to the lower wavelengths in soluble sericins. The intensity of the amide II band was reduced and shifted to lower wavelengths as a result of hydrolysis. In DSC analysis, all sericins showed endothermic peaks around 200$^{\circ}C$ and insoluble sericin showed another peak at 250$^{\circ}C$. The endothermic peak of the insoluble sericin was found at higher temperature compared with those of the soluble sericins which showed at 300$^{\circ}C$. Whiteness of the various sericins became higher as low＞high＞PP＞PA＞PK＞IN and yellowness were PK＞PA＞PP＞low＞high. In pack test, the skin packed with the non-woven fabric treated with the various sericins was more smooth and less oily.

• Journal of Sericultural and Entomological Science
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• v.25 no.2
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• pp.44-50
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• 1984

The effects of sodium pyrophosphate, sodium tripolyphosposphate and ethylene diamine tetraacetic acid as a degumming aid reagent were investigated under the conditions of underground water and dimineralized water for the scouring water sources. The changes of water qualities by adding the condensed sodium phosphates and the physical properties of scoured silk fabric were examined, respectively. 1. The water hardness of underground water was decreased by adding the condensed sodium phosphates and it was further reduced according to the increasing temperature. The water hardness reducing power of sodium pyrophosphate was a little stronger than that of sodium tripolyphosphate. 2. The sodium silicate as an alkaline reagant for scouring decreased the water hardness, but the sodium carbonate increased it in the underground water. 3. The pH value of 0.4% soap and 0.25% sodium silicate mixed solution after boiling was. 9.80, but it was leveled upto 9.90 by adding 0.05% sodium pyrophosphate and upto 9.95 by 0.02% ehtylene diamine tetraacetic acid, respectively. 4. The masking action of Fe$\^$3+/ ions dissolved in the scouring water was more remarkable by ethylene diamine tetraacetic acid than by the condensed sodium phosphates. Of the condensations, sodium tripolyphosphate was more effective than sodium pyrophosphate in the action. 5. Genrally, the dimineralized water scouring increased the boil-off ratio with reducing the flexural rigidity of fabric which was negatively related with the favorablility of hand-touch more than the underground one did. 6. Under the underground water scouring, the addition of ethylene diamine tetraacetic acid increased the boil-of ratio and compressive elasticity of fabric with reducing the flexural rigidity more than that of the condensed sodium phosphates did. 7 The additions of sodium tripolyphosphate and ethylene diamine tetraacetic acid reduced the flexural rigidity of fabric with raising the boil-off ratio even in the dimineralized water scouring, but there was no sifnificant difference between both of them.

• International Journal of Industrial Entomology and Biomaterials
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• v.8 no.1
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• pp.101-106
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• 2004

The process of removal of gummy proteinous material sericin from silk is commonly called as degumming loss or boil-off loss ratio. In the present study, the boil-off loss ratio in the cocoon shells of twelve multivoltine${\times}$bivoltine hybrids and their parents were analysed. Inheritance pattern of boil-off loss ratio was analysed in crosses involving high and low boil-off loss parents, F$_1$s, F$_2$s and back-crosses by parent off spring regression analysis. Heterosis and heterobeltiosis was also analysed for this character, Highly significant (P＞0.01) variations were observed in eight out of ten multivoltine and two out of five bivoltine parents indicating the presence of genetic variation in the expression of boil-off loss ratio. Among F$_1$ hybrids, ten hybrids expressed significant (P＞0.01) variations when compared with control hybrid PM${\times}$NB$_4$D$_2$. Significant negative heterosis was expressed in three multi ${\times}$ bi hybrids viz., BL67${\times}$CSR$_{101}$, 96A${\times}$CSR$_{19}$ and 96C${\times}$CSR$_{19}$, which is desirable for this character, whereas expression of heterobeltiosis was significant only with one hybrid, 96C${\times}$CSR$_{18}$ in desired direction. Studies on inheritance pattern showed that the character is heritable and contribution percentage of female and male in the ratio of 50.9: 49.1 and it appears that both the parents are influencing in the expression of boil-on loss ratio in silkworm. Based on the overall performance and evaluation by multiple trait evaluation index and also considering the expression of the boil-off loss ratio three hybrids vix., BL67 ${\times}$ CSR$_{101}$, 96A${\times}$CSR$_{19}$ and 96C${\times}$CSR$_{18}$ were found superior and recommended for commercial exploitation.n.ion.n.

• Journal of Sericultural and Entomological Science
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• v.16 no.1
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• pp.21-48
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• 1974

The studies were carried out to disclose the physical and chemical properties of sericin fraction obtained from silk cocoon shells and its characteristics of swelling and solubility. The following results were obtained. 1. The physical and chemical properties of sericin fraction. 1) In contrast to the easy water soluble sericin, the hard soluble sericin contains fewer amino acids include of polar side radical while the hard soluble amino acid sach as alanine and leucine were detected. 2) The easy soluble amino acids were found mainly on the outer part of the fibroin, but the hard soluble amino acids were located in the near parts to the fibroin. 3) The swelling and solubility of the sericin could be hardly assayed by the analysis of the amino acid composition, and could be considered to tee closely related to the compound of the sericin crystal and secondary structure. 4) The X-ray patterns of the cocoon filament were ring shape, but they disappeared by the degumming treatment. 5) The sericin of tussah silkworm (A. pernyi), showed stronger circular patterns in the meridian than the regular silkworm (Bombyx mori). 6) There was no pattern difference between Fraction A and B. 7) X-ray diffraction patterns of the Sericin 1, ll and 111 were similar except interference of 8.85A (side chain spacing). 8) The amino acids above 150 in molecular weight such as Cys. Tyr. Phe. His. and Arg. were not found quantitatively by the 60 minutes-hydrolysis (6N-HCI). 9) The X-ray Pattern of 4.6A had a tendency to disappear with hot-water, ether, and alcohol treatment. 10) The partial hydrolysis of sericin showed a cirucular interference (2A) on the meridian. 11) The sericin pellet after hydrolysis was considered to be peptides composed with specific amino acids. 12) The decomposing temperature of Sericin 111 was higher than that of Sericin I and II. 13) Thermogram of the inner portioned sericin of the cocoon shell had double endothermic peaks at 165$^{\circ}C$, and 245$^{\circ}C$, and its decomposing temperature was higher than that of other portioned sericin. 14) The infrared spectroscopic properties among sericin I, II, III and sericin extracted from each layer portion of the cocoon shell were similar. II. The characteristics of seriein swelling and solubility related with silk processing. 1) Fifteen minutes was required to dehydrate the free moisture of cocoon shells with centrifugal force controlled at 13${\times}$10$^4$ dyne/g at 3,000 R.P.M. B) It took 30 minutes for the sericin to show positive reaction with the Folin-Ciocaltue reagent at room temperature. 3) The measurable wave length of the visible radiation was 500-750m${\mu}$, and the highest absorbance was observed at the wave length of 650m${\mu}$. 4) The colorimetric analysis should be conducted at 650mu for low concentration (10$\mu\textrm{g}$/$m\ell$), and at 500m${\mu}$ for the higher concentration to obtain an exact analysis. 5) The absorbing curves of sericin and egg albumin at different wave lengths were similar, but the absorbance of the former was slightly higher than that of the latter. 6) The quantity of the sericin measured by the colorimetric analysis, turned out to be less than by the Kjeldahl method. 7) Both temperature and duration in the cocoon cooking process has much effect on the swelling and solubility of the cocoon shells, but the temperature was more influential than the duration of the treatment. 8) The factorial relation between the temperature and the duration of treatment of the cocoon cooking to check for siricin swelling and solubility showed that the treatment duration should be gradually increased to reach optimum swelling and solubility of sericin with low temperature(70$^{\circ}C$) . High temperature, however, showed more sharp increase. 9) The more increased temperature in the drying of fresh cocoons, the less the sericin swelling and solubility were obtained. 10) In a specific cooking duration, the heavier the cocoon shell is, the less the swelling and solubility were obtained. 11) It was considered that there are differences in swelling or solubility between the filaments of each cocoon layer. 12) Sericin swelling or solubility in the cocoon filament was decreased by the wax extraction.. 13) The ionic surface active agent accelerated the swelling and solubility of the sericin at the range of pH 6-7. 14) In the same conditions as above, the cation agent was absorbed into the sericin. 15) In case of the increase of Ca ang Mg in the reeling water, its pH value drifted toward the acidity. 16) A buffering action was observed between the sericin and the water hardness constituents in the reeling water. 17) The effect of calcium on the swelling and solubility of the sericin was more moderate than that of magnecium. 18) The solute of the water hardness constituents increased the electric conductivity in the reeling water.