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Assam Agricultural University, Jorhat
Assam Agricultural University is the first institution of its kind in the whole of North-Eastern Region of India. The main goal of this institution is to produce globally competitive human resources in farm sectorand to carry out research in both conventional and frontier areas for production optimization as well as to disseminate the generated technologies as public good for benefitting the food growers/produces and traders involved in the sector while emphasizing on sustainability, equity and overall food security at household level.
Genesis of AAU -
The embryo of the agricultural research in the state of Assam was formed as early as 1897 with the establishment of the Upper Shillong Experimental Farm (now in Meghalaya) just after about a decade of creation of the agricultural department in 1882. However, the seeds of agricultural research in today’s Assam were sown in the dawn of the twentieth century with the establishment of two Rice Experimental Stations, one at Karimganj in Barak valley in 1913 and the other at Titabor in Brahmaputra valley in 1923. Subsequent to these research stations, a number of research stations were established to conduct research on important crops, more specifically, jute, pulses, oilseeds etc. The Assam Agricultural University was established on April 1, 1969 under The Assam Agricultural University Act, 1968’ with the mandate of imparting farm education, conduct research in agriculture and allied sciences and to effectively disseminate technologies so generated. Before establishment of the University, there were altogether 17 research schemes/projects in the state under the Department of Agriculture. By July 1973, all the research projects and 10 experimental farms were transferred by the Government of Assam to the AAU which already inherited the College of Agriculture and its farm at Barbheta, Jorhat and College of Veterinary Sciences at Khanapara, Guwahati.
Subsequently, College of Community Science at Jorhat (1969), College of Fisheries at Raha (1988), Biswanath College of Agriculture at Biswanath Chariali (1988) and Lakhimpur College of Veterinary Science at Joyhing, North Lakhimpur (1988) were established. Presently, the University has three more colleges under its jurisdiction, viz., Sarat Chandra Singha College of Agriculture, Chapar, College of Horticulture, Nalbari & College of Sericulture, Titabar. Similarly, few more regional research stations at Shillongani, Diphu, Gossaigaon, Lakhimpur; and commodity research stations at Kahikuchi, Buralikson, Tinsukia, Kharua, Burnihat and Mandira were added to generate location and crop specific agricultural production packages.
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ThesisItem Open Access DEVELOPMENT OF NANOPARTICLE-BASED FOOD EMULSION TO STABILIZE CURCUMIN IN AQUEOUS FOOD MEDIUM(2023) Gade, Priyanka; Purkayastha, Manashi DasEmulsions are thermodynamically unstable bi-phase systems whose basic components include a continuous phase, a dispersed phase, and an emulsifier. Emulsifier is an amphiphilic compound that immediately adsorbs to freshly formed oil droplets and prevents their aggregation. Based on the nature of origin, emulsifiers are classified into natural and synthetic emulsifiers; as the latter is often associated with carcinogenic properties, now researchers are heading towards identifying and exploring natural emulsifiers (without derivatizing or modifying the chemical composition). Among natural compounds/molecules that can act as emulsifiers, proteins are of great interest because of their wide functional properties. Even though these protein molecules can stabilize emulsions in the initial period, in the long term they tend to de-stabilization. Conjugation of proteins to other bioactive molecules like polyphenols can enhance their functionalities, thereby improving the stability of protein-stabilized emulsions. In this study, rapeseed protein-tea polyphenol (P-P) nano-conjugates were created, which were then used at different concentrations (0.25% to 1.5% (w/v)) to fabricate emulsions (namely E1 (0.25%), E2 (0.5%), E3 (0.75%), E4 (1.0%), E5 (1.25%), and E6 (1.5%)) by using curcumin containing oil (5 mg curcumin/ml of oil) and aqueous medium (200 mM phosphate buffer, pH-7.0). The synthesized emulsions were exposed to various storage and thermal processing conditions (4℃, 25℃, 90℃, and 121℃), and subsequently, their physico-chemical characteristics were analyzed. Emulsifying capacity and centrifugal stability were found to increase with an increase in conjugate concentration. Droplet size of emulsions increased throughout the storage period; samples stored at 4℃ (without any thermal pre-treatment) recorded smaller diameter, and sterilized emulsions (stored at 4℃) recorded larger size. Zeta potential showed higher negative values for emulsions stored at 4℃ (without any thermal pre-treatment) and lower values for the sterilized samples (stored at 4℃). Values of zeta potential were seen to increase with the storage period. Creaming was observed in E1 (0.25%) of emulsions stored at 4℃ and E1 (0.25%) & E2 (0.5%) of emulsions stored at 25℃ (without any thermal pre-treatment) from the storage period of 24 h, whereas thermally treated emulsions (stored at 4℃) with low concentrations of conjugates started to show creaming tendency from the storage period of 168 h (7 days). Entrapped curcumin was recorded more in samples stored at 4℃ (without any thermal pre-treatment), and the least was noted in the sterilized emulsions (stored at 4℃). Values of loading efficiency of curcumin and DPPH scavenging activity also followed the same pattern. There is a significant difference (p<0.05) for all tested characteristics of samples throughout the storage period, and among all the emulsions under this study, E6 (bearing 1.5% conjugate) stored at 4℃ (without any thermal pretreatment) was found to perform the best. Further, the performance of P-P conjugates in stabilizing curcumin was compared against six commercially renowned permissible food emulsifiers (adding their maximum concentration as prescribed by FSSAI guidelines). These were as follows: CMC-Carboxyl methyl cellulose (0.5% w/v), DATEM-Di-acetyl-tartaric acid ester of mono-triglycerides (0.2% w/v), GMS-Glycerol Mono-stearate (0.5% w/v), INS-475 - Polyglycerol Polyricinoleate esters (0.5% w/v), LACTEM- Lactic Acid Esters of Mono –Diglycerides (0.2% w/v), and Soy lecithin (1.5% w/v). Except for soy lecithin, all other tested emulsifiers failed to form stable emulsions with curcumin-loaded oil under the given test conditions. Hence, a comparative study was carried out between soy lecithin and P-P conjugate-stabilized emulsions. Following the same concentration as adopted for P-P conjugates, soy lecithin formed emulsion at all given concentrations (e1- 0.25%, e2 - 0.5%, e3- 0.75%, e4 -1%, e5-1.25%, e6 - 1.5%); however, dispersion of curcumin appeared to be non-homogeneous (as evident from a dense yellow emulsified phase at the top). Soy lecithin showed less emulsifying capacity at lower concentrations compared to P-P conjugates, and immediately after thermal treatment, most of the emulsions formed by soy lecithin presented complete separation. Based on visual observations, the dispersibility of curcumin by soy lecithin was poorer than that of the P-P conjugates. After 72 h, there was a complete separation of phases in soy lecithin-based emulsions stored at 25℃. At the end of the stipulated storage period, i.e., 336 h (14 days), the best emulsion amongst the soy lecithin stabilized ones, i.e., e6 (stored at 4℃ without any thermal pretreatment), could entrap only 0.08 mg of curcumin per ml of emulsion, which was half of the curcumin entrapped by that of P-P conjugates (i.e., 0.186 mg/ml), and exhibited nearly 3 times less antioxidant activity (14.2%) than that showed by P-P conjugates (42.1%). So, the overall performance of soy lecithin was low compared to P-P conjugates at the given test conditions to stabilize curcumin in the aqueous phase. And thus, the synthesized nanoconjugates can be recommended for food and pharmaceutical usage, if high dispersibility of curcumin is desired therein.ThesisItem Open Access Phytochemical analysis of dried leaves of Paederia foetida(2023) Saikia, Prapti; Baishya, SamindraWith advancing gain of interest in medicinal herb due to its health benefits, drying of leaves play an important role in packaging and preservation. Being highly perishable, drying of P. foetida leaves can be utilised for its widespread use. The present study was carried out to identify the impact of drying methods on phytochemical content and antioxidant activity of P. foetida leaves. Different drying techniques utilised in the study were oven drying at 40ºC, 50ºC, sun drying, solar drying and shade drying. Preliminary phytochemical screening of ethanolic extract revealed presence of phenol, flavonoid, tannin, glycoside and terpenoid. Impact of drying methods on phytochemical content was found significant. Moisture content of dried sample ranged from 11.18%in oven dried sample @50 ºC to 12.76% in shade dried sample. Total phenolic, flavonoid and tannin contents varied from 10.97- 16.46 mg GAE/g, 2.22- 8.39 mg QE/g, 4.25- 4.90 mg TAE/g respectively with highest amount in solar dried sample. Ascorbic acid content was retained most in oven dried sample @50 ºC with 8.4 mg/100 g and lowest in shade dried sample with of 7.2 mg/100 g. Total antioxidant activity ranged from 10.30-15.69 mg AAE/g with maximum activity in solar dried sample. Scavenging activity using DPPH free radical portrayed a gradual increase in activity with increased concentration of sample extract. Highest inhibition was recorded for solar dried sample. Solar dried sample was found best amongst the drying treatments on retention of bioactive compounds and antioxidant activity.ThesisItem Open Access PECTIN-BASED MICROENCAPSULATION OF PROBIOTICS FOR IMPROVING SURVIVAL IN GASTRO-INTESTINAL TRACT(2023) Gogoi, Pratyasha; Saikia, AnantaThe probiotic organisms exert various health benefits. The viability of probiotics is reduced while passing through the stomach and upper intestine because of the low pH. In this study, pectin was extracted from lemon peels and pumpkin, and microcapsules were made by encapsulation of probiotic microorganism species Lactobacillus plantarum, L. delbrueckii and Pediococcus. pentosaceous with plant-based pectin through emulsification. The degree of esterification was highest in lemon pectin (66.10%) with the highest encapsulated bead yield of 13.08g/g pectin. The initial probiotic cell count of L. plantarum, L. delbrueckii and P. pentosaceous was 9.54, 9.61 and 9.51 log cfu/ml respectively. The microcapsules of L. delbrueckii gave the highest viability attributed to its higher tolerance to acid. The microcapsules of L. plantarum, L. delbrueckii and P. pentosaceous achieved encapsulation yields of 84%, 86% and 83% from lemon pectin and, 81%, 83% and 83% from pumpkin pectin respectively. However, results of simultaneous incubation in simulated gastric and intestinal fluid revealed a slight reduction in the viability of encapsulated cells remaining within 5 log cfu/ml. The microencapsulated beads were observed under the inverted microscope to detect the presence of bacteria after gram staining which showed gram- positive cells. No difference was detected in the bead appearance by environmental scanning electron microscopy, except that the pectin beads made from lemon peel pectin resulted in lesser severe wrinkles on the surface. The overall study indicated that the most stable microcapsules were made from lemon peel pectin with the potential for industrial application.ThesisItem Open Access DEVELOPMENT OF BIODEGRADABLE BIOPLASTIC FROM BANANA PEELS(2023) Talukdar, Nilakshi; Boro, Robin ChandraThe development of biodegradable bioplastic has gained significant attention in recent years due to its potential as a sustainable solution for plastic waste management. The present study was to develop bioplastic from banana peels and characteristic its physical properties. The biofilm was prepared from banana peels by casting method using glycerol (10%) as a plasticizer and corn starch as co-biopolymer. Five banana peel bioplastics (T1 -T5) were prepared with different concentrations of corn starch (2%, 4%, 6%, 8% and 10% respectively) and the bioplastic (T0) without corn starch was taken as a control. Based on the study, the thickness of the bioplastic was recorded in the range of 0.38 mm - 0.59 mm. The bioplastic (T4) with 8% corn starch was found to have the highest tensile strength of 0.388 MPa as compared to other treatments. The highest water solubility was observed in the bioplastic (T5) with 10% corn starch. At different temperatures (250C, 300C and 350C), the water vapour transfer rate (WVTR) of the bioplastic were studied. The best result for WVP was observed in T5 where the concentration (10%) of corn starch was highest. The biodegradability of the films was determined by carbon dioxide evolution. There was a gradual increase in carbon dioxide evolution from day 7th to day 90th. After 90 days the net carbon dioxide evolution was recorded as 0.5190 g for T4 (corn starch 10%). Lastly, the microbial growth was detected only after 60 days of storage. The study revealed that the treatment T4 (Glycerol 10% and 8% corn starch) is found to be the best among the treatments considering its highest tensile strength (0.388 MPa), elongation percent (9.77%), maximum load (2.48 N), intermediate solubility (34.12%), thickness (0.56 mm), susceptibility to microbial contamination and biodegradability. Effects of concentration of corn starch showed positive effect on water vapor transmission rate of the bioplastics. By using bioplastic, the environmental pollution can be reduced as well as the waste banana peels can be turned into a new value-added biodegradable plastic product.ThesisItem Open Access MECHANICAL DE-SEEDING OF ROSELLE AND ITS EFFECTS ON QUALITY OF BREWED ROSELLE TEA(2023) Mudoi, Nani Gopal; Borah, AbhijitThe manual deseeding of Roselle is time-consuming and labour-intensive process. Dealing with bulk quantities manual, deseeding can result in loss of edible parts of calyx due to human error and drudgery. Therefore, considering the need and expectations of the small-scale manufactures of Roselle products, an efficient, low-cost, fast deseeding design was developed and compared with hand/manual deseeding. The developed machine has a foot paddle and link mechanism. Coil spring mechanism has been provided for return action of the punching tool to its original position. The machine cost was estimated to be Rs.1800/-. The rate of deseeding by the machine was 2.5 kg/h with minimum broken percentage producing good quality of deseeded calyces. When compared with manual deseeding, it was found that manual deseeding capacity was 1.5 kg/h apart from quality degradation of the calyces. Brewed Roselle tea was taken for quality tests to see the effect of mechanical deseeding against manual deseeding. Mechanically and manually deseeded whole calyx and powder (dried at 80 °C) were selected as treatments. The quality parameters like Anthocyanin (monomeric), Total phenol content, Total flavonoid, Antioxidant activity, Total soluble solids, Colour, Sensory Analysis, Bulk density, True density, Porosity were determined for both mechanical and manual deseeded calyces and powders. The highest mean of monomeric-anthocyanin content was found in mechanically deseeded powder and whole calyces’ tea (39.83 mg/ml and 16.59 mg/ml), same trend was observed for the phenol content (26.03 mg/ml and 14.58 mg/ml), flavonoid content (24.37 mg/ml and 16.56 mg/ml) and antioxidant activity (88.70% and 87.60%). Sensory assessment of the Roselle tea revealed that mechanically deseeded whole calyx dried at 80 °C was highly accepted and judged best among other Roselle tea samples. Mechanically deseeded calyces dried at 80 °C exhibit higher porosity (51.41%) and lower bulk density (0.69 gm/cm3), which plays important role for production of tea or herbal infusion of dried Roselle because a lower bulk density allows for better infusion and extraction of flavours and compounds. The result obtained from the quality parameters opened up a possibility having a good impact on the small-scale manufactures, marginal farmers and Self-help groups (SHGs) for having a good quality Roselle’s products and smooth deseeding operation with the deseeder.ThesisItem Open Access PREPARATION OF STARTER CULTURE FROM DIFFERENT SOURCES OF GUNDRUK & GUNDRUK FERMENTATION FROM WASTE LEAVES OF CABBAGE(2023) Mahanta, Jyotiraditya; Nath, TankeswarGundruk is an ethnic fermented food produce by fermenting leafy vegetables primarily valued for its uniquely appetizing taste and flavor. From nutritional standpoint, Gundruk can be considered as a concentrated source of minerals, vitamins, therapeutically active compounds and probiotics. During this present investigation, effort towards finding the possibility of improving the production technology of fermenting Gundruk from waste leaves of cabbage has been made. 3 different samples of Gundruk were collected from 3 different districts of Assam (Jorhat, Biswanath and Sonitpur), from which 6 different bacterial strains were isolated (coded as JR1, JR2, BN1, BN2, SP1 and SP2) characterized and screened for Gundruk fermentation as starting culture. Along with these starting cultures, a mixture of microbial isolates directly isolated from the collected Gundruk samples by soaking them with sterilized distilled water and keeping in shaking incubator overnight at room temperature and 200rpm (coded as JR3, BN3 and SP3). These mixture cultures were also used directly for Gundruk fermentation as stating cultures, separately. Proximate analysis of all the final Gundruk products produced after 14 days of fermentation and sun drying was carried along with the raw waste cabbage leaves (used as substrate). The results obtained after the proximate analysis showed that the crude fiber and moisture contents of all the Gundruk samples decreased considerably over the non-fermented leaves to a level of 8.61 percent and 8.13 percent from 12.67 percent & 82.3 percent, respectively. But, all the other minerals (Potassium, Phosphorus, Iron, Calcium, Magnesium, Sodium and Zinc) as well as the ash contents found to be increased considerably in fermented products over the non-fermented one. Gundruk product fermented using bacterial isolates showed increased level of mineral profile than the Gundruk fermented naturally. The highest level of K (257.29mg/100g), P (43.59mg/100g), Mg (33.79mg/100g) and Ca (63.79mg/100g) were found in product treated with the bacterial isolate BN1 (isolated from Biswanath-Gundruk). This increase in the minerals content of the Gundruk product might be associated with the presence of more numbers of lactic acid bacteria in the added starting cultures which facilitate the process of fermentation leading to the release of more minerals. Microbial load was evaluated in each final product and it was found that the product inoculated with bacterial mixture SP3 (prepared from Sonitpur-Gundruk) used as starter culture showed the highest microbial growth (7.17 log cfu/g)) over all the treated and absolute controlled-products. Sensory evaluation of all the final fermented products was carried out by 20 evaluators using 9-point hedonic rating scale. The highest scoring in terms of flavor, taste and overall appearance goes with the product treated with bacterial isolate JR2 (isolated from Jorhat-Gundruk) as starting culture as. However, there were no considerable difference found among the different products in terms of color and appearance. From the present investigation it can be concluded that it is possible to prepare Gundruk with acceptable quality characteristics using readily available seasonal leafy vegetables, specifically unused leaves of cabbage as well as known bacterial isolates, isolated from naturally fermented Gundruk product under controlled conditions. However, to make it commercialized product it needs more investigation in details like standardization of starter culture, evaluation of more leafy vegetables, standardization of procedures for storage as well as packaging and estimation profitability etcThesisItem Open Access DEVELOPMENT OF GLUTEN-FREE BISCUITS USING RICE, SOY OKARA AND ELEPHANT APPLE POMACE(2023) Lahkar, Anandita; Purkayastha, Manashi DasFuture years are going to witness a marked rise in the demand for gluten-free (GF) foods, as the prevalence of gluten-related disorders is rising globally. In the present study, two set of GF biscuits (using Bora chaul and Komal chaul) were prepared. In the first set of biscuit formulation, Bora chaul was used on the basis of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100% (w/w) substitution of soy okara respectively and were accordingly coded as B1, B2, B3, B4, B5, B6, B7, B8, B9, B10. Similarly, in the second set of biscuit formulation, Komal chaul was added as 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100% (w/w) replacement of soy okara respectively and were accordingly coded as K1, K2, K3, K4, K5, K6, K7, K8, K9 and K10. In both the formulations, T0 bearing only wheat flour (i.e. absence of rice or okara) served as the control; while S0 served as the formulation containing 100% soy okara alone (i.e. absence of rice and refined wheat flour). The products’ physical, proximate and organoleptic properties were evaluated. In Bora chaul-soy okara biscuits, bulk density ranged from 0.54±0.01 g/cm3 (B1) to 0.49±0.01 g/cm3 (B10) which were higher than T0 (0.42±0.01 g/cm3). Minimum spread ratio of samples was observed in S0 followed by B1 with B6 to B10 in close proximity to T0. In B1 to B10, ash content, crude protein and crude fibre content ranged within 2.20±0.02% to 1.96±0.03%, 12.36±0.13% to 5.89±0.17%, and 11.98±0.36% to 3.59±0.33%, respectively, and were higher than those of T0. Total carbohydrates and energy value were lowest in S0 and highest in B9 and B10. Likewise, Komol chaul-soy okara biscuits’ bulk density ranged from 0.56±0.00 g/cm3 (K1) to 0.50±0.01 g/cm3 (K10) and were higher than those of T0 and S0. Spread ratio of samples were intermediate to that found for T0 (maximum) and S0 (minimum), with K7 to K9 comparable with T0. Mineral content ranged from 2.21±0.02% to 1.94±0.01%, crude protein between 13.03±0.20% to 6.28±0.36%, crude fibre within 12.1±0.04% to 3.95±0.21% and total carbohydrates from 47±0.57% to 70.34±0.09%. Energy value was observed lowest in K4, and highest in K9 and K10, which were slightly lesser than that of T0. Based on sensory scores, it was deduced that replacement of soy okara upto 30% in Bora chaul biscuits and upto 40% in Komol chaul biscuits can result in satisfactory products. Production of these kind of nutrient-dense gluten-free baked goods would prove suitable for valorization of soy okara as-well-as provide fibre-rich snacking option for gluten sensitive consumers.ThesisItem Open Access OPTIMIZATION OF Tamarindus indica L. DYE FOR SURFACE ENRICHMENT OF SILK FABRIC(2023) BURAGOHAIN, SHILPI; Boruah, SunitaThe art of dyeing and printing has played a vital role in adding beauty to textile. Increased awareness regarding environmental issues has vastly encouraged the idea of using eco-dyes and eco-printing for textiles offers numerous benefits, as their preparation and application involved minimal or no harsh chemical reaction that are good for nature and also have positive effects on the wearer’s health. In the field of textiles, the present era can truly be called the era of eco-dyeing and printing. Value addition of the silk fabric through eco-dyeing and printing will lead to more consumer acceptance in the National on International markets thereby, more profitability. Dyeing and printing also add natural value to mulberry silk, making it more attractive and allowing for the creation of diversified products. In light of these benefits, the researcher conducted a study on “Optimization of Tamarindus indica L. Dye for Surface Enrichment of Silk Fabric”, with the following objectives: • Optimization of dyeing condition of Tamarind seed dye on mulberry silk fabric • Surface enrichment of dyed fabric using eco-printing method • Analysis of properties of dyed and printed fabrics To carry out the study, mulberry silk fabric with two different mordants (Alum and Aloe vera) was selected. Seeds of tamarind (Tamarindus indica L.) were selected after pre-testing as a natural dye source. For the study, selected natural dye and mulberry silk fabrics were collected from the local market of Jorhat district, and mordants were collected from the campus of the Assam Agricultural University, Jorhat. Identification of samples was done by assigning names to each a C (Control sample), CT (Without mordanted), CTA1 (Alum mordanted), CTA2 (Aloe vera mordanted), DMEA1 (Dyed fabric with Manjistha Eco-print using Alum as mordant), and DMEA2 (Dyed fabric with Marigold Eco-print using Alum as mordant). Different dyeing conditions such as extraction medium, extraction time, dye material concentration, dyeing time, mordant concentration, mordanting time and mordanting methods such as (pre, simultaneous and post) were optimized. A pre-treatment method such as degumming was carried out for mulberry silk fabric. The optimum dye extracting time was 60 minutes. The extraction was used to dye mulberry silk fabric and the optimum conditions were 1% dye at 60°C for 60 minutes. The surface of the dyed silk fabric was enriched using eco-printing techniques. Pre-testing was done followed by four techniques i.e., Bundle dye technique, Plain background technique, Tannin target iron blanket technique and Plain target dye blanket technique. Among them, the Plain target dye blanket technique was selected for the study as it shows a better printing effect than others. SEM analysis was done to determine the surface morphology of the control and dyed silk fabric and the differences in morphology and elements between them were clearly visible. FTIR analysis was used to identify the functional groups and various bonds that were present in the fabric and visible in different spectra. The crystallinity region of the fabrics was identified using XRD analysis and an alteration in the crystallinity structures of dyed silk fabrics compared to the control was discovered. The Ultraviolet Protection Factor (UPF) of the control, non-mordanted, and different dyed silk fabrics were evaluated and found that the Ultraviolet protection property was increased in dyed silk fabrics. The samples were evaluated visually and with the help of Greyscale for determining the colourfastness properties such as Colourfastness to Sunlight, Colourfastness to Washing, Colourfastness to Crocking or Rubbing (Dry and Wet), Colourfastness to Pressing (Dry and Wet), Colourfastness to Perspiration (Acidic and Alkaline), which exhibited fair to good ratings with noticeable stained to negligible stained. It was clear from the present investigation that colourfastness properties of natural mordanted samples showed good fastness properties to sunlight, washing, crocking, and pressing as compared to metallic mordant samples. The control, dyed and printed silk fabric were undergone for a series of physical experiments. The dyed, mordanted and printed silk fabrics were found to be increased in terms of fabric count (Ne), fabric thickness (mm), weight (GSM), tensile strength (N), moisture regain (%), wicking height (cm) and crease recovery (angle) than control silk fabric. The elongation (%) and stiffness (cm) were found to be decreased in dyed, mordanted and printed silk fabric as compared to the control one. Hence, it could be concluded from the study that natural dye with natural mordant and eco-print obtained an excellent effect on mulberry silk fabric and it can be used for the textile industry and eco-friendly textile manufacturing.ThesisItem Open Access BIOMASS EXTRACTION FROM Cocos nucifera HUSK- AN AGRO-ORGANIC WASTE FOR COLORATION OF SILK FABRIC(2023) DAS, PURNIMA; Kalita, Binita BaishyaIn present years, natural dyes have gained popularity as a safer alternative to dangerous synthetic colors. Eco-friendly, environment-safe natural dyeing techniques and products are today’s entail for textiles. Natural coloring substances are now growing trends for their use all over the world because of health hazards and toxicity problems created by synthetic dyes. Considering the growing importance of natural dyes all over the world, the present investigation entitled “Biomass extraction from Cocos nucifera husk- An agro-organic waste for coloration of silk fabric” was undertaken to assess the following objectives: 1. Extraction and optimization of dyeing conditions of coconut husk dye on mulberry silk fabric. 2. Surface enhancement of dyed fabric using eco-printing method. 3. Evaluation of properties of dyed and printed fabrics. To carry out the study, coconut (Cocos nucifera) husks dye was used as a natural dye to develop variety of natural colors on mulberry silk fabric using alum and gallnut as mordants. For extraction of dye, an aqueous medium was employed with an optimum wavelength of 570 nm which showed the highest (1.62%) absorbency value. Pre-treatment method such as degumming was carried out for the mulberry silk fabric to enhance the lustre, color and texture of the dyed silk fabric. Based on the objectives different dyeing parameters were optimized such as extraction medium, extraction time, dye concentration, dyeing time, mordant concentration, mordanting time and mordanting methods. The optimum dye extraction time was 60 min. Dyeing process was carried out keeping the material to liquor ratio 1:30 at a constant temperature of 70ºC for 45 min. The optical density values of the dye solution before and after dyeing were carried out to find out absorption percentage (%). The mordant concentration, mordanting time and mordanting methods were also optimized to get better shades. Brown, light brown and medium to deep brown colors were obtained from dyed, alum mordanted and gallnut mordanted silk fabric, respectively. The physical and colorfastness properties of the fabrics were evaluated. As regards physical properties, the dyed with and without mordant and mordanted eco-printed silk fabrics were found to be increased in terms of fabric count (Ne), thickness (mm), weight (g/m2), crease recovery (angle), stiffness (cm), elongation (%) compared to control fabric. However, the decreased in tensile strength (N), moisture regain (%) and wicking height (cm) were found in dyed with and without mordant as well as mordanted eco-printed silk fabrics. From the test results, it can be concluded that all the samples of silk fabrics showed satisfactory results and wide scope of development of textile materials. The colorfastness to sunlight, washing, crocking, pressing and perspiration were assessed for dyed and eco-printed silk fabrics in terms of color alteration and all the samples found to be good to very good fastness and there was slightly to negligible staining of the color. The morphological and structural characteristics of control and dyed fabrics were assessed using SEM, FTIR and XRD analysis. SEM images of control and dyed silk fabrics revealed that slightly rough surface with irregularities, cylindrical shapes, presence of fibrils, nodes. The control and alum mordanted dyed sample showed smoother and more uniform surface than the without mordanted and gallnut mordanted samples. FTIR spectrum of the control and dyed silk fabric samples showed the presence of various components such as alkenes, aliphatic amines, alcohols, carboxylic acids, esters, ethers, phenol ring, 1º amines, alcohols, phenols. The crystallinity region of the fabrics was identified by XRD analysis and alterations in the crystallinity structures of dyed silk fabrics compared to control were discovered. The Ultraviolet protection properties of control, dyed with and without mordanted silk fabrics were evaluated and found that the Ultraviolet protection properties of dyed fabrics were more as compared to control fabric. Both alum and gallnut mordanted fabrics showed good UV protection. However, control and without mordanted dyed fabric showed very poor UV protection.
