Higher Gum Content Research Articles

A novel cascade glycolic acid pretreatment-alkali degumming method for producing hemp fiber

Hemp fiber is a promising textile resource. Because hemp fibers contain high gum content, an efficient degumming method needs to be developed. This study proposed a novel cascade degumming process coupling organosolv pretreatment and alkali boiling. Glycolic acid was optimally selected as a pretreatment reagent. The cascade process achieved a high lignin removal rate (69.81%) and hemicellulose removal rate (84.83%). The degummed hemp fibers showed excellent properties (4.18 ± 0.99 cN/dtex and 8.34 ± 0.01 dtex). Moreover, the glycolic acid solution could be reused three times without purification. The glycolic acid pretreatment led to decreased consumption of alkali reagents by 96.15%. Furthermore, the effect of glycolic acid pretreatment on lignin removal was analyzed by chemical composition analysis, FTIR, XRD, TGA, GPC, and HSQC NMR analysis. These results indicate that the novel cascade degumming process is an efficient and eco-friendly degumming method.

Growth, yield and quality of two guar (Cyamopsis tetragonoloba L.) ecotypes affected by sowing date and planting density in a semi-arid area.

The growth period, phenology, grain yield and gum content of two different guar ecotypes were studied in response to different sowing dates and plant densities. A two-year field experiment was conducted as a split-factorial in a randomized complete block design (RCBD) with three replicates in the research field of Tarbiat Modares University during 2016 and 2017 growing season. Main plots consisted of four sowing dates (May 21, June 4, June 21 and July 5 in 2016 and May 10, May 26, June 10 and June 26 in 2017), and subplots including three plant densities (13, 20 and 40 plants m-2) and two ecotypes (Pakistani and Indian). Based on findings, the phenological traits, plant height, grain yield and harvest index were significantly affected by plant density. The effect of ecotypes was statistically significant (p<0.05) on all traits except harvest index in the first year. Furthermore, the seed sowings on May 21 and May 26 with 13 plants m-2 led to highest grain yield (3004.8 and 2826.10 kg.ha-1 for two consecutive years). The high gum content (33.68 and 33.78% for two consecutive years) was also recorded for Pakistani ecotype while for gravity, Indian ecotype showed higher value in both crop years. By and large, the Pakistani ecotype showed better response compared to the Indian one in both years, especially in 1st and 2nd sowing dates.

A Framework for Identification of Stable Genotypes Basedon MTSI and MGDII Indexes: An Example in Guar (Cymopsis tetragonoloba L.)

Guar, the most popular vegetable, is tolerant of drought and is a valuable industrial crop enormously grown across India, Pakistan, USA, and South Africa for pharmaceutically and cosmetically usable galactomannan (gum) content present in seed endosperm. Guar genotypes with productive traits which could perform better in differential environmental conditions are of utmost priority for genotype selection. This could be achieved by employing multivariate trait analysis. In this context, Multi-Trait Stability Index (MTSI) and Multi-Trait Genotype-Ideotype Distance Index (MGIDI) were employed for identifying high-performing genotypes exhibiting multiple traits. In the current investigation, 85 guar accessions growing in different seasons were assessed for 15 morphological traits. The results obtained by MTSI and MGIDI indexes revealed that, out of 85, only 13 genotypes performed better across and within the seasons, and, based on the coincidence index, only three genotypes (IC-415106, IC-420320, and IC-402301) were found stable with high seed production in multi-environmental conditions. View on strengths and weakness as described by the MGIDI reveals that breeders concentrated on developing genotype with desired traits, such as quality of the gum and seed yield. The strength of the ideal genotypes in the present work is mainly focused on high gum content, short crop cycle, and high seed yield possessing good biochemical traits. Thus, MTSI and MGIDI serve as a novel tool for desired genotype selection process simultaneously in plant breeding programs across multi-environments due to uniqueness and ease in interpreting data with minimal multicollinearity issues.

Research of Microbial-gel Combined Flooding Technology of Ba19 Block in Baolige Oilfield

Bal9 fault block is a medium-high temperature (58°C) reservoir in Baolige Oilfield. The crude oil is characterized by poor physical properties which has high wax and high gum content. The oil-water viscosity ratio is high and this leads to a low water flooding efficiency. The reservoir heterogeneity is high and the contradictions between layers are prominent. According to the characteristics of the oilfield, a microbial-gel combined flooding technology with the microbial flooding as the main body and the gel flooding as the auxiliary is developed to improve the overall development effect of the oilfield water flooding. Microorganism can improve the physical properties of crude oil, and appropriate gel flooding should be carried out to enlarge the sweep volume of microorganism work and improve the effect of microbial-gel combined flooding. By continuous application of this technology in Baolige Oilfield, the concentration of microorganisms is maintained at about 106 a/ml, and the whole microbial field is formed. The average annual reduction rate of crude oil is 48.1%. The microbial-gel combined flooding technology is verified to increase the recovery factor by 9.5%. Since the combined flooding was carried out in 2010, the recoverable reserves of the Ba19 block increased by 630,600 tons.

Exploring the edible gum (galactomannan) biosynthesis and its regulation during pod developmental stages in clusterbean using comparative transcriptomic approach

Galactomannan is a polymer of high economic importance and is extracted from the seed endosperm of clusterbean (C. tetragonoloba). In the present study, we worked to reveal the stage-specific galactomannan biosynthesis and its regulation in clusterbean. Combined electron microscopy and biochemical analysis revealed high protein and gum content in RGC-936, while high oil bodies and low gum content in M-83. A comparative transcriptome study was performed between RGC-936 (high gum) and M-83 (low gum) varieties at three developmental stages viz. 25, 39, and 50 days after flowering (DAF). Total 209,525, 375,595 and 255,401 unigenes were found at 25, 39 and 50 DAF respectively. Differentially expressed genes (DEGs) analysis indicated a total of 5147 shared unigenes between the two genotypes. Overall expression levels of transcripts at 39DAF were higher than 50DAF and 25DAF. Besides, 691 (RGC-936) and 188 (M-83) candidate unigenes that encode for enzymes involved in the biosynthesis of galactomannan were identified and analyzed, and 15 key enzyme genes were experimentally validated by quantitative Real-Time PCR. Transcription factor (TF) WRKY was observed to be co-expressed with key genes of galactomannan biosynthesis at 39DAF. We conclude that WRKY might be a potential biotechnological target (subject to functional validation) for developing high gum content varieties.

Studies on Particle Size Distribution of Rice Bran Wax in the Presence of Gum and Oil in Hexane Medium

Particle size distribution of rice bran wax crystals formed during cooling in hexane medium has been investigated by dynamic light scattering technique. Solutions of wax (1 g), gum–wax (1:1) in food-grade n-hexane (100 ml), gum–wax–physically refined rice bran oil (PRBO) (1:1:30 by weight) in hexane (70 ml) and rice bran oil (RBO)–hexane miscella (RBOM) were crystallized at various temperatures of 5–40 °C range. Crystallization of gum and wax, incubation time and temperature, inhibition in crystal growth in the presence of gum and triglyceride of PRBO and crude RBOM have been investigated. Temperature range of 5–12 °C for high gum content oil and 40–60-min incubation time have been optimized for effective fractionation of gum and wax from oil–hexane miscella to get higher centrifugation mass yield with better purity. The presence of gum and wax in 1:1 ratio has been shown to produce a maximal number of smaller-sized wax crystals at 15 °C.

Identification of genomic SSRs in cluster bean (Cyamopsis tetragonoloba) and demonstration of their utility in genetic diversity analysis

Cluster bean (Cyamopsis tetragonoloba), also known as guar, is an important industrial crop owing to its high gum content in the endosperm. Availability of sufficient genomic resources, especially, DNA markers, greatly aids genetic improvement of a crop. In this study, we identified 1859 genomic SSRs, for the first time, from 1091 scaffolds representing 60% of the cluster bean genome. Further we validated 89 of these markers using 54 cultivated guar accessions and two wild relatives, Cyamopsis serrata and Cyamopsis senegalensis. Seven SSRs were monomorphic even with the wild relatives while 11 were polymorphic only between species with 72 being polymorphic within C. tetragonoloba accessions. Polymorphism information content of the markers ranged from 0.017 to 0.62 with an average of 0.19. Cross-transferability rates of 62% observed for the genomic SSRs suggested divergence between the cultivated and the wild species. Genomic SSRs mined in this study though showed a high proportion of dinucleotide repeats (48.5%), while tri- and tetranucleotide repeats were found to be more polymorphic. Genetic diversity analysis of the 56 accessions using the 82 polymorphic markers could differentiate the cultivated accessions of C. tetragonoloba into four major clusters, two of which had two sub-clusters while the wild accessions formed a separate cluster. Since chromosome-wide distribution of the SSRs is unknown and genetic linkage maps in guar is not available, we used the soybean genome as a reference and identified 29 genome-wide and unlinked SSRs markers. Population structure analysis (PSA) using these markers revealed six subpopulations, more or less similar to the major and sub-clusters identified by the neighbor joining analysis. Further PSA identified an entry from subpopulation 6 to have admixture with the wild relatives. Annotation of the validated genomic SSR containing sequences using green plant nr protein database revealed that 16 of them were genic in nature. This is the first report on genomic SSRs and their utilization in unraveling the genetic diversity in cluster bean.

Natural Fibres From the Bark of Mulberry Branches for Textile Application

Fibers with low gum content were extracted from the bark of mulberry branches by a combination of bacteria and peroxide treatments. The bark of mulberry branches, with 30% cellulose, is a copious and inexpensive source of natural fibers. However, fibers extracted by microwave, enzyme or alkali had a high gum content (15.5% for hemicellulose and 8.6% for lignin), which rendered them difficult to be made into high- value textiles. In this research, strains with high polygalacturonase activities and subsequent hydrogen peroxide decreased the hemicellulose content to 2.5% and lignin content to 2.4%. Mulberry fibers in our study could be spun into yarns with a fineness of 18.2 tex. Compared to flax yarns, mulberry fiber yarns had a tenacity 20% higher, an elongation 18% higher and an unevenness 30% lower. Cotton/mulberry fiber fabrics had softer and smoother hand than cotton/flax fabrics. Overall, the fibers in our study show better potential for industrial textile applications than those in previous studies.

Bioregulators protected the leaf anatomy and photosynthetic machinery under water deficit stress in chickpea (Cicer arietinum L.)

A field experiment was conducted during the season kharif 2008 and 2009 to find out response of cluster bean varieties to growth regulators. RGC-936 recorded in significantly higher amount of total nitrogen (N), phosphorus (P) uptake and protein content during both the years over RGC-1017, RGC-1003 and RGC-1002. Seed + foliar application with thiourea @ 500 ppm recorded maximum total N and P uptake. Quality parameters viz. gum and protein in seed, were found highest in cultivar RGC 1017 which was at par with RGC-1002 and RGC-1003 and all these three varieties were significantly superior over RGC 936. Variety RGC-1017 recorded 15.3% higher gum content over RGC-936. Among the growth regulators. maximum gum content in seed were recorded with the seed + foliar application of thiourea @ 500 ppm. However, it was found statistically at par with the seed + foliar application of TGA @ 100 ppm and significantly superior to rest of the treatments in current study.

Influence of growth regulators on nutrient concentrations, nutrient uptake and quality parameters of cluster bean varieties

A field experiment was conducted during the season kharif 2008 and 2009 to find out response of cluster bean varieties to growth regulators. RGC-936 recorded in significantly higher amount of total nitrogen (N), phosphorus (P) uptake and protein content during both the years over RGC-1017, RGC-1003 and RGC-1002. Seed + foliar application with thiourea @ 500 ppm recorded maximum total N and P uptake. Quality parameters viz. gum and protein in seed, were found highest in cultivar RGC 1017 which was at par with RGC-1002 and RGC-1003 and all these three varieties were significantly superior over RGC 936. Variety RGC-1017 recorded 15.3% higher gum content over RGC-936. Among the growth regulators. maximum gum content in seed were recorded with the seed + foliar application of thiourea @ 500 ppm. However, it was found statistically at par with the seed + foliar application of TGA @ 100 ppm and significantly superior to rest of the treatments in current study.

Cluster bean [cyamopsis tetragonoloba (L.) Taub.], an importantindustrial arid legume: A review

Cluster bean is an important legume cultivated mostly on marginal and sub marginal lands of arid and semi-arid regions. Overall, India produces around 80% of global cluster bean production. It is cultivated on more than 4 m ha in India, Rajasthan alone accounts for around 80% of the area and production. Owing to its demand in the international market, it has been introduced in the non-traditional growing areas like Andhra Pradesh, Tamil Nadu, Karnataka, Maharashtra and Chhattisgarh. Further, its cultivation is also being taken up under irrigated conditions during summer. Cluster bean seed (endosperm) is a source of a natural hydrocolloid (galactomannan/‘guar gum’). The gum has unique abilities with multiple commercial applications like textile, printing, paper, cosmetics, mining, pharmaceutical, petroleum, natural gas, well drilling and oil industries. Green pods are nutritionally rich and are routinely consumed as vegetable especially in northern and western parts of India. Additionally, cluster bean has been reported to have beneficial effects when cultivated as an intercrop. Cluster bean meal (high protein content) obtained from seed coat and germ cell is an excellent feed for monogastric animals. Cluster bean cultivars with high gum content (&gt;32%) and viscosity (4000-5000 cps) are more preferred for export. The value of cluster bean exports from India has increased from Rs 242 crores (1994) to Rs 2100 crores (2012-13). This review presents the various aspects of cluster bean cultivation and its emergence as an important industrial crop.

Studies on the adhesion behavior of water-based adhesives blended with asan gum

The influence of asan gum, a locally available waste material obtained from the Terminalia alata tree, in blends with waterborne natural rubber adhesive and poly(vinyl acetate), on the lap shear strength and the peel strength has been investigated. Both the strength values increase, even with a small quantity of the gum. At a higher gum content, both these parameters, however, decrease. Fourier Transform Infrared studies reveal that there is no covalent bonding between the gum and the adhesives, although some hydrogen bonding exists in the poly(vinyl acetate) blend. Morphological studies reveal mechanical interlocking of the adhesive in the substrates. The pseudoplastic nature of the gum-modified waterborne adhesives has been confirmed from rheological studies using a Brookfield viscometer. The higher lap shear and peel strength values of the gum-modified adhesives compared to the control adhesives are attributed to the higher shear modulus of the former. The 100% modulus and tensile strength of the adhesives blended with the gum are also higher, compared to their controls.