Cocoon Cooking Research Articles

Novel ultrasonic-assisted cleaner technology for cocoon brushing at low temperature

Cocoon brushing is a vitally important process in silk reeling, it closely relates to raw silk quality and reeling efficiency. In this research, an ultrasonic-assisted cocoon brushing process is proposed, which can achieve cocoon reeling and silk cleaning at lower temperature and alleviate the problem of using excessive temperature to cocoon brushing in silk reeling factories. The cocoon brushing effect of different treatment conditions is investigated by fuzzy orthogonal method to obtain the optimal process: ultrasonic temperature 80 °C, ultrasonic time 40 s, ultrasonic power 144 W, cocoon cooking time 3 min. Compared with the conventional process, the total number of cocoon brushing is reduced by 4.75 times, the reelability percentage is heightened 11.39% and the rushing upon cocoons per myriameter is lessened 2.53 times. After ultrasonic treatment, the secondary structure and thermal stability of raw silk are not change. The sericin distribution is more uniform and the mechanical properties are improved to a certain extent. The temperature of this process is about 15 °C lower than the silk reeling factory and it can save 93 MJ for 1 kg of raw silk per reeling. Results show that ultrasonic can be used to develop an green process for cocoon brushing, which may provide a technical reference for the silk environmental protection production.

Use of Pineapple Fruit Juice as a Technology for Softening of Oak Tasar Cocoons

Oak tasar cocoons are difficult to reel due to the presence of high amounts of protein-tannin complexes. The chemical methods developed for reeling these cocoons is not readily adopted by the common tasar silk reelers and weavers due to various reasons including relatively low reeling performance, low fuel efficiency, complicated procedure and prolonged cooking time. Proteolytic enzymes that cleaves the internal peptide bonds in an amino acid chain have the potential to effect partial solubilisation of the proteinaceous silk gum (sericin) involved in biding the silk (fibroin) strands together in silkworm cocoon, an essential step in the silk cocoon cooking and reeling. Pineapple fruit extract rich in cysteine endopeptidases has a potential application in cooking and reeling of oak tasar (Antheraea proylei J.) silk cocoons which cannot be softened by boiling in plain water unlike the mulberry cocoons (Bombyx mori L). The experimental results from the present investigation on the oak tasar cocoon cooking with pineapple extract at room temperature and subsequent study have indicated for an applicability of pineapple extract as an effective agent for the oak tasar (Antheraea proylei J.) cocoon cooking and reeling. It is observed that enzymatic cocoon cooking has advantages over chemical method. The method involving pineapple extract is a relatively better method regarding its overall better reeling performances and also mostly due to the abundant availability of pineapples grown in the oak tasar belt in India. Moreover, the method is environmentally friendly and is readily accessible to the common tasar silk reelers and weavers.

Effects of Low-Temperature Cocoon Cooking Method and Chemicals on Raw Silk Cohesion and Physical Properties

Effects of Low-Temperature Cocoon Cooking Method and Chemicals on Raw Silk Cohesion and Physical Properties

Recovery of silk sericin from the filature wastewater by using a novel foam fractionation column

Silk industry was an important mainstay of Asian textile industry. However, a large volume of filature wastewater is produced during the cocoon cooking step and it might lead to severe environment pollution without effective treatment. In fact, the wastewater contained an important and valuable protein, silk sericin. In this work, foam fractionation was purposed to recover silk sericin (SS) from the filature wastewater. A novel column with groined internal component (GIC) was developed for strengthening foam fractionation at room temperature. Compared with the control column, the collected foam from the experimental column possessed of a low liquid holdup because the low gas-liquid weakened the viscous effect caused by the rising velocity of the bubbles, when the rising foam passed through the corner channels creased by GIC. Under the suitable operating conditions of pH 4.0, length of GIC 400 mm, volumetric air flow rate 200 mL/min and pore diameter of gas distributor 180 μm, the enrichment ratio and the recovery percentage of SS reached 6.77 and 80.29%, respectively. This work is expected to provide a cost-effective technique to recover SS from the filature wastewater, and to facilitate the industrialization of foam fractionation in wastewater treatment.

Studies on Tasar Cocoon Cooking Using Permeation Method

Cocoon cooking is an important process before reeling of tasar silk yarn. Cooking ensures loosening of the filaments in the tasar cocoons thereby easing the process of yarn withdrawal during reeling process. Tasar cocoons have very hard shell and hence these cocoons need chemical cooking process to loosen the silk filaments. Attempt has been made in this article to study the effect of using vacuum permeation chamber for tasar cocoon cooking in order to reduce the cooking time and improve the quality of tasar silk yarn. Vacuum assisted permeation cooking method has been studied in this article on tasar daba cocoons for cooking efficiency, deflossing and reelability. Its efficiency has been evaluated with respect to different cooking methods viz, traditional and open pan cooking methods. The tasar silk produced after reeling process has been tested for fineness, strength and cohesion properties. Results indicate that permeation method of tasar cooking ensures uniform cooking with higher efficiency along with better reeling performance and improved yarn properties.

The extraction of sericin protein from silk reeling wastewater by hollow fiber nanofiltration membrane integrated process

Sericin protein having high additional value in many industries such as textiles, pharmaceuticals and cosmetics is always discharged in silk reeling wastewater which causes serious environmental pollution. In this paper, different combined process of acidulation precipitation–ultrafiltration (UF)–nanofiltration (NF) was investigated and optimized to recover high-purity sericin protein from silk reeling wastewater. Inner-pressure hollow fiber polyamide NF composite membrane was prepared through the interfacial polymerization. The results showed that the recovery of sericin protein in the supernatant liquid after acidulation precipitation treatment could reach 72.1% when using the UF membrane (MWCO 6000)–NF membrane integrated process. When the mixture of sericin protein precipitation and concentrated liquid after UF and NF filtration was diluted four times, the better comprehensive results were achieved. The loss rate of sericin protein and the salt content of concentrated liquid was 34.1% and 29.1%, respectively while the conductivity after UF membrane treatment was lower than that of the local tap water. More than 86% sericin protein from cocoon cooking wastewater, refining wastewater and mixed wastewater could be recovered by the optimized UF–NF combination process. Using 0.2molL−1 hydrochloric acid as the cleaning agent could effectively recover the water flux of NF membrane.

Silk reeling of silkworm cocoon in strongly alkaline electrolyzed water as a sericin swelling agent at low temperature

Strongly alkaline electrolyzed water (SAEW) was used as a sericin swelling agent for silk reeling from cocoons of the silkworm Bombyx mori. Tap water was electrolyzed with a laboratory-made combined water electrolyzer to generate SAEW with pH 11.50. The hardness of SAEW was 30% less than that of the tap water, whereas the concentrations of Na+ in SAEW were 18% higher than those in the tap water. The pH of the SAEW was stable for at least a month in an airtight container. Cocoons were immersed in pH 11.50 SAEW for 15 min with shaking, which replaces one step of the complex cocoon cooking process in the traditional reeling method (TRM) where penetration is achieved by repeatedly alternating high and low temperatures. The swollen cocoons were transferred into fresh pH 11.50 SAEW for reeling at the same, or slightly lower, temperature. The sericin loss from the whole cocoon in pH 11.50 SAEW is about 3.5% and the tensile property of the single silk fibroin filament is similar to or better than that of TRM. Silk reeling in SAEW involves only one step of cocoon swelling in pH 11.50 SAEW (70°C), which replaces a series of complex processes including water penetration, water absorption, swelling, and then silk reeling in the TRM. A novel low-temperature and simple reeling technology suitable for development by the silk industry is described.

Separation of silkworm proteins in cocoon cooking wastewaters via nanofiltration: Effect of solution pH on enrichment of sericin

Cocoon cooking wastewater contains waste silkworm proteins including sericin, which is a valuable raw material for many industries including cosmetics and pharmaceuticals. Sericin can be recovered via nanofiltration (NF) with high efficiency; however the process conditions need to be optimized to maximize separation. In this study, the effect of solution pH on NF performance was investigated for separation of silkworm proteins towards sericin enrichment. Solution pH (3.5–9.0) slightly influenced sericin rejection, which was higher than 80% in all cases. On the other hand, solution pH significantly influenced transmission of contaminant proteins, which was highest (0.52) at pH 3.5 and lowest (0.06) at pH 9.0. Increased transmission of contaminant proteins at acidic pH was attributed to possible effects of concentration polarization and increased ionic strength. Although acidic conditions (pH 4.5) favored sericin enrichment, the instantaneous purity of sericin in the retentate remained at 0.48–0.52 at pH 3.5–9.0. Furthermore, working at acidic pH caused severe fouling problems; more than threefold increase occurred in flux decline; with an increase of flux decline from 20% to 69% and fouling resistance from 3.8 × 10 13 m −1 to 15.5 × 10 13 m −1 (almost fourfold) when pH was reduced from 6.4 to 4.5. The contribution of fouling resistance to total resistance increased from 32–40% (pH 6.4) to 70% and 53% in acidic and alkaline conditions, respectively. Concentrating the wastewater at pH 4.5 had adverse impacts on rejection performance of NF membrane; rejection of sericin and contaminant proteins decreased from 78% to 52% and from 33% to 9%, respectively, as volume reduction factor increased from 1.00 to 1.70. Correspondingly, sericin purity in the retentate decreased from 0.59 to 0.55. The pH adjustment had no benefit for separation of sericin from contaminant proteins, and hence it was decided not to apply pH adjustment in NF stage. Instead, a two-stage process, NF (at original pH of 6.4) plus ethanol-induced precipitation were adopted, which enabled enrichment of sericin 1 from 80.0% to 92.9%. The product was considered to be of high quality as it contained greater than 90% sericin.

Effect of cocoon cooking conditions on reeling performance of semi-dried Indian bivoltine hybrid cocoons

Effect of cocoon cooking conditions on reeling performance of semi-dried Indian bivoltine hybrid cocoons

Studies on the systematization of cocoon cooking

Studies on the systematization of cocoon cooking

Method of analysis on the thermal properties in the cocoon cooking process

Method of analysis on the thermal properties in the cocoon cooking process

Transfer characteristics of the cocoon cooking and reeling process

Transfer characteristics of the cocoon cooking and reeling process

Development of a computer control system of the cocoon cooking process

Development of a computer control system of the cocoon cooking process

On the expert system by means of applying principal component analysis for cocoon cooking

On the expert system by means of applying principal component analysis for cocoon cooking

Expert system for cocoon cooking by the application of Fuzzy rules

Expert system for cocoon cooking by the application of Fuzzy rules

Effect of degree of cocoon drying and cocoon cooking conditions on reeling performance and quality of raw silk of Indian bivoltine hybrid cocoons

Effect of degree of cocoon drying and cocoon cooking conditions on reeling performance and quality of raw silk of Indian bivoltine hybrid cocoons

Effect of cocoon cooking condition on cocoon filament unwinding tension, reeling characteristics and quality characteristics of raw silk of Indian bivoltine hybrid cocoons

Effect of cocoon cooking condition on cocoon filament unwinding tension, reeling characteristics and quality characteristics of raw silk of Indian bivoltine hybrid cocoons

Treatment of silk production wastewaters by membrane processes for sericin recovery

Sericin protein, although a valuable resource for many industries including cosmetics, pharmaceutical and biomedical, has been discarded as a waste in silk industry, causing environmental pollution. This paper describes determination of a membrane-based process for sericin recovery from cocoon cooking wastewaters (CCW) that will enable value-added utilization of waste sericin. The iso-electric point (p I) of sericin was found as 5–6, whose MW was distributed as 180–200, 70–80, 30–40 and 10–25 kDa. Prior to membrane filtration, sericin was separated from other impurities via centrifugation (CFG) followed by microfiltration (MF) in the pre-treatment stage, which also helped minimize post membrane fouling. Ultrafiltration (UF) and nanofiltration (NF) were adopted at a pH equal to p I of sericin. UF achieved partial recovery of sericin polypeptides at 37–60%, which was attributed to increased transmission of uncharged sericin polypeptides at their p I. On the other hand, NF achieved sericin recovery as high as 94–95%, containing all MW fractions. Severe flux decline was the major problem due to protein–membrane interactions and high sericin concentrations, where concentration polarization mainly had a dominant effect. Although flux declines were as high as 58–88% in UF and 70–75% in NF, flux recovery by at least 83% was achieved by chemical cleaning using NaOH and free chlorine.

Development of an Expert System for Cocoon Cooking by using Neural Network Technology

Development of an Expert System for Cocoon Cooking by using Neural Network Technology

Studies on bivoltine cocoon reeling - Influence of cocoon cooking condition and croissure length on quality characteristics of raw silk of Indian bivoltine hybrid cocoons

Studies on bivoltine cocoon reeling - Influence of cocoon cooking condition and croissure length on quality characteristics of raw silk of Indian bivoltine hybrid cocoons