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.

Aroids and Water Relations: An Overview

Abstract: Major edible aroids, elephant foot yam, taro and tannia constitute staple food for the low income group and tribal people in India. As such their yield potential has not been well realized. Limited studies have been conducted on the scientific water management, especially water relations and water requirement of aroids. These crops are mostly rainfed. However, they are known to have high water requirement due to great transpiration loss and long duration. Their large leaves are extensive transpiring surfaces through which large quantities of water are transpired. Effects of water deficit stress during various phases of these crops are reported to affect the productivity, particularly, if stress occurs during the tuber bulking phase rather than tuber initiation or maturation phases. Elephant foot yam produces large corms when water supply is adequate. Continuous flooding adversely affects the performance. The initiation of sprouts from seed corms to initiation of senescence is decided by the availability of soil moisture. Taro comes up well in moist environments. Tuber bulking phase has been considered as the most critical phase in taro. Tannia is relatively more tolerant to dry conditions and is sensitive to water-logging, but performs better under irrigation especially when rainfall is irregular. Thus water can be considered as the most critical input in aroid cultivation. Limited studies conducted on water management and water relations of major edible aroids are reviewed here.

Behaviour of Cassava Starch in Various Solvents

Abstract: Solubilization and gelatinization of cassava starch in various solvents were studied. Solvents of different polarity and water miscibility were taken. Formalin was also used. The results indicated that starch gelatinizes in dimethylsulfoxide (DMSO), ethanediol, glycerol and formalin at varying temperatures. The viscosity of 2% solution in these solvents varies largely. The clarity is almost equal, whereas sol stability is highest in case of formalin. The iodine staining experiment shows that, in formalin solution a reversible complex is formed between starch and formaldehyde. Verhalten von Cassavastarke in verschiedenen Losungsmitteln. Es wurde die Loslichkeit und Gelatinierung von Cassavastarke in verschiedenen Losungsmitteln untersucht. Dabei wurden Losungsmittel unterschiedlicher Polaritat und Wassermischbarkeit verwendet. Auch Formalin wurde berucksichtigt. Wie die Ergebnisse zeigten, gelatiniert die Starke in Dimethylsulfoxid (DMSO), Ethandiol, Glycerin und Formalin bei verschiedenen Temperaturen. Die Viskositat der 2%igen Losungen in diesen Losungsmitteln variiert uber einen weiten Bereich. Die Durchsichtigkeit ist fast gleich gros, die Losungsstabilitat ist bei Formalin am grosten. Die Iod-Farbungsversuche zeigen, das in Formalin-Losung ein reversibler Komplex zwischen Starke und Formaldehyd gebildet wird.

An Efficient Blade Type Rasper for Cassava Starch Extraction

Abstract: The cassava tubers, being highly perishable, should be immediately processed into starch or flour for value addition, which enhances the income of farmers resulting in food security and rural employment. Starch is generally prepared by wet extraction process, in which rasping or crushing is an important unit operation for the disintegration of the cell wall and washing out of the starch granules by water. In the commonly used raspers, mild steel sheets with nail punched protrusions are fixed around a wooden drum which rotates inside a crushing chamber to crush the tubers. The loss of sharpness of the protruded sheets necessitated frequent replacement and this increased the cost of processing. Hence a cost effective cassava rasper consisting of a crushing drum of mild steel pipe with high speed blade sets fixed on its circumference was developed and tested for its performance by changing the rasper speed and water inflow rate. Experiments were carried out to extract starch from cassava at different rasper speeds (1000, 1200 and 1400 rpm) and water inflow rates (7, 15 and 23 l min -1 ). The particle size analysis of the crushed mash obtained from the slurry showed that the volume surface mean diameter was found to be the highest followed by mass mean diameter and volume mean diameter. As the speed of rotation increased, the average particle size decreased, whereas with increase in water flow rate, the particle size increased. Maximum fineness modulus of the crushed mash was 4.82. The capacity of the machine was found to be about 900-1000 kg h -1 . The amount of starch extracted was 18.98% giving rise to a starch recovery of 83.39%.

Desynapsis in Colocasia antiquorum Schott.

Abstract: A culture ofColocasia antiquorum Schott. (2n=28) exhibiting desynapsis was detected in the course of cytological screening of a large number of cultivars maintained at the Institute. Intensive studies on the course of meiosis in this material as well as in the normal plants were made commencing from pachytene stage. Meiosis in the normal plants was regular, leading to the production of 95% stainable pollen. On the other hand, meiosis in the desynaptic material was found to be highly irregular resulting in the formation of over 80% sterile pollen. In its meiotic behaviour, the desynapticColocasia conforms to the “complete” type of desynaptics. The available evidence suggests a spontaneous origin of the desynaptic through gene mutation. The utility of this material in the study of unravelling basic cytogenetical problems is discussed.

Molecular diversity of Fusarium oxysporum causing rot diseases of vanilla in south India

Abstract: Incidence of root, stem and beans rot of vanilla (Vanilla planifolia Andrews) caused by Fusarium oxysporum Schlecht was surveyed in vanilla growing areas of south India during December 2008. The incidence of the disease varied from 1 to 100% in different locations. A total of 60 isolates of F. oxysporum were obtained from diseased samples, and nine morphologically different isolates were taken for molecular characterization using Randomly Amplified Polymorphic DNA (RAPD) markers to study the genetic variability if any, among them. PCR amplification of total genomic DNA with random oligonucleotide primers generated unique banding patterns depending upon primers and isolates. Nine oligonucleotide primers were selected for the RAPD assays, which resulted in 384 bands for nine isolates of F. oxysporum. The number of bands obtained was entered into a NTSYS and the results showed that the variability among the pathogen isolates was moderate. The nine isolates studied were grouped into single major cluster at 0....