Central Tuber Crops Research Institute

About: Central Tuber Crops Research Institute is a facility organization based out in Thiruvananthapuram, Kerala, India. It is known for research contribution in the topics: Starch & Fermentation. The organization has 475 authors who have published 587 publications receiving 10285 citations.

Plantain peel - a potential source of antioxidant dietary fibre for developing functional cookies

Abstract: Plantain cultivar Nendran is popular as a staple food in many parts of India and deep fried chips made from raw matured Nendran are one of the popular snack items in India. This study aims to utilize peel from Nendran variety- the main byproduct of banana chips industry- to develop high fibre cookies with enhanced bioactive content. Proximate analysis indicated that peels are rich in total dietary fibre (64.33 g/100 g), vitamins (Folic acid- 33.12 mg/100 g) and minerals (Potassium- 35.61 mg/100 g). Nendran Peel Flour (NPF) was extracted with hexane, ethyl acetate and methanol. Phenolic and flavonoid content was high for ethyl acetate extract (15.21 and 9.39 mg QE/g dry weight). Methanol extract was more potent in reducing Copper ion (2.36 μM TR/g dry weight) and scavenging NO (IC50-381.71 μg/mL). Ethyl acetate extract was capable of scavenging DPPH and hydroxyl radical. HPLC profiling showed presence of gallic acid, protocatechuic acid, rutin hydrate and quercetin in ethyl acetate extract and gallic acid, chlorogenic acid and vanillic acid in methanol extract. Cookies prepared with NPF possess higher total dietary fibre content. There was a decrease in spread ratio, breaking strength and browning index of cookies as the percentage of NPF increased. NPF incorporation gradually increased the phenolic content from 4.36 to 5.28 mg GAE, compared to control cookie (3.21 mg GAE). DPPH scavenging activity also increased with increase in NPF. Hence NPF is a very good source of antioxidant dietary fibre and acceptable cookies can be produced by replacing wheat flour with 10 % NPF.

Identification of antimicrobial compound, diketopiperazines, from a Bacillus sp. N strain associated with a rhabditid entomopathogenic nematode against major plant pathogenic fungi

Abstract: Aims To purify and characterize antimicrobial compounds from Bacillus sp. strain N associated with rhabditid entomopathogenic nematode (EPN). Methods and Results The cell-free culture filtrate of a bacterium associated with an EPN, Rhabditis (Oscheius) sp., exhibited strong antimicrobial activity. The ethyl acetate extract of the bacterial culture filtrate was purified by silica gel column chromatography to obtain three diketopiperazines (DKPs). The structure and absolute stereochemistry of this compound were determined based on extensive spectroscopic analyses (FABMS, 1H NMR, 13C NMR, 1H-1H COSY, 1H-13C HMBC) and Marfey's method. The compounds were identified as cyclo(l-Pro-l-Leu), cyclo(d-Pro-l-Leu) and cyclo(d-Pro-l-Tyr), respectively. Three DKPs were active against all the five fungi tested (Aspergillus flavus, Candida albicans, Fusarium oxysporum, Rhizoctonia solani and Penicillium expansum) and are more effective than the standard fungicide bavistin. The highest activity of 4 μg ml−1 by cyclo(l-Pro-l-Leu) and cyclo(d-Pro-l-Tyr) was recorded against P. expansum, a plant pathogen responsible for causing postharvest decay of stored apples and oranges. Cyclo(d-Pro-l-Leu) recorded good antibacterial activity against all the four bacteria tested (Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa), and cyclo(l-Pro-l-Leu) and cyclo(d-Pro-l-Tyr) recorded good activity only against Gram-positive bacteria. To our knowledge, this is the first report of antifungal activity of the DKPs against the plant pathogenic fungi F. oxysporum, R. solani and P. expansum. The production of cyclo(l-Pro-l-Leu), cyclo(d-Pro-l-Leu) and cyclo-(d-Pro-l-Tyr) by a bacterium associated with EPN is also reported here for the first time. Conclusions Isolated DKPs demonstrated high antimicrobial activity against bacteria and fungi, especially against plant pathogenic fungi. We conclude that the bacterium associated with EPN is a promising source of natural bioactive secondary metabolites which may receive great benefit in the field of agriculture. Significance and Impact of the Study This study is a significant contribution to the knowledge of compounds unique from EPN bacteria as potential sources of new drugs in the agricultural and pharmacological industry.

Biocontrol Efficacy of Bacillus subtilis Strains Isolated from Cow Dung Against Postharvest Yam (Dioscorea rotundata L.) Pathogens

Abstract: The biocontrol potential of Bacillus subtilis isolated from cow dung microflora was investigated in vitro and in vivo against two postharvest yam pathogenic fungi, Fusarium oxysporum and Botryodiplodia theobromae. B. subtilis strains inhibited the growth of F. oxysporum and B. theobromae in vitro in liquid medium in the range of 49.3-56.6% and in solid medium in the range of 31.0-36.0%, in comparison to the corresponding growth of fungi without bacterial inoculation. The interaction between B. subtilis CM1 and F. oxysporum was also studied by scanning electron microscopy. Chitinase production was demonstrated in vitro when B. subtilis was grown in the presence of colloidal chitin as the sole carbon source in a liquid medium. In vivo study showed that B. subtilis strains inhibited the growth of fungi (F. oxysporum and B. thobromae) up to 83% in wound cavities of yam tubers.

Nanopore-based detection and characterization of yam viruses.

Abstract: We here assessed the capability of the MinION sequencing approach to detect and characterize viruses infecting a water yam plant. This sequencing platform consistently revealed the presence of several plant virus species, including Dioscorea bacilliform virus, Yam mild mosaic virus and Yam chlorotic necrosis virus. A potentially novel ampelovirus was also detected by a complimentary Illumina sequencing approach. The full-length genome sequence of yam chlorotic necrosis virus was determined using Sanger sequencing, which enabled determination of the coverage and sequencing accuracy of the MinION technology. Whereas the total mean sequencing error rate of yam chlorotic necrosis virus-related MinION reads was 11.25%, we show that the consensus sequence obtained either by de novo assembly or after mapping the MinION reads on the virus genomic sequence was >99.8% identical with the Sanger-derived reference sequence. From the perspective of potential plant disease diagnostic applications of MinION sequencing, these degrees of sequencing accuracy demonstrate that the MinION approach can be used to both reliably detect and accurately sequence nearly full-length positive-sense single-strand polyadenylated RNA plant virus genomes.

Synthesis and Characterization of low DS Succinate Derivatives of Cassava (Manihot esculenta Crantz) Starch

Abstract: Succinylation of cassava starch was carried out in aqueous medium to prepare derivatives with low degree of substitution (DS) and the physicochemical properties of the products were determined. A response surface design was used for the experiment with three levels of each of the three variables viz., concentration of succinic anhydride, reaction time and pH of the reaction medium. The reaction was followed in terms of the DS of the products and reaction efficiency (RE). The degree of substitution of the derivatives varied from 0.001 to 0.022 and reaction efficiency from 2.2 to 46.8%. The DS and RE showed an adequate fit to a second order polynomial model of the variables used. Succinylation brought about increase in the swelling volume, peak viscosity and paste clarity of the starch. However, the pasting temperature and solubility did not show any significant change. The in-vitro α-amylase digestibility of the succinylated derivatives decreased in comparison to that of native starch and this decrease correlated with a corresponding increase in DS.