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.

Comparative production of glucose and high fructose syrup from cassava and sweet potato roots by direct conversion techniques

Abstract: High fructose syrup (HFS) is a highly valued liquid sweetener for beverage, confectionery and processed food industry, owing to its special attributes like high solubility and non-crystalline nature. Even though 85% HFS production is from corn, increased food demand has necessitated the search for alternative substrates and starchy root crops like cassava and sweet potato are potential raw materials. However, the economic production needs direct use of the roots and simplification of the cost-intensive steps. This study aims at the direct enzymatic conversion of roots for HFS production. Glucose yield was compared from six treatment systems viz., liquezyme–dextrozyme (T1), Stargen (T2), Stargen in two split doses (T3), Spezyme–Stargen (T4), Stargen (60 °C;T5) and Spezyme–Stargen (60 °C; T6). Glucose was higher (22–25%) from cassava than sweet potato (14.0–15.7%), owing to the high starch content in cassava. Conversion to glucose was higher in T1–T4 (95–98%) compared to 88–92% for T5 and T6. Although the fructose yield was more from cassava (8.36–9.78%) than sweet potato (5.2–6.0%), percentage conversion was similar (37–38%) for both the roots. The cost of production of HFS could be reduced by the direct hydrolysis of root slurry using Stargen. Industrial relevance The conventional process for HFS production involved three cost-intensive enzyme steps such as liquefaction, saccharification and isomerization and the major raw material is starch. Economic production using cheaper raw materials and simplification of the process are the decisive factors for the widespread use of HFS in the developing and less developed countries. The present study aimed at the direct conversion of cassava and sweet potato root slurry (without conversion to starch) through the use of improved enzymes like Spezyme and Stargen and mild operating conditions of pH and temperature. The cost of production of HFS could be reduced by using the wet root slurry and performing the Stargen aided saccharification at room temperature, followed by isomerization at 60 °C using Sweetzyme T.

Ectopic Expression of Rice PYL3 Enhances Cold and Drought Tolerance in Arabidopsis thaliana

Abstract: Abscisic acid (ABA) plays an important role in plant development and adaptation to abiotic stresses. The pyrabactin resistance-like (PYL) gene family has been characterized as intracellular ABA receptors in Arabidopsis. We describe here the functional characterization of PYL3 ABA receptor from a drought-tolerant rice landrace Nagina 22 (N22). The induced expression level of the PYL3 transcript was observed in the N22 under different stress treatments, including cold, drought, high temperature, salt and ABA. In contrast, the expression of PYL3 was down-regulated in drought-susceptible rice cv. IR64 in response to above stresses. C-terminal GFP translational fusion of OsPYL3 was localized to both cytosol and nucleus explaining in part functional conservation of PYL protein as ABA receptor. Arabidopsis transgenic lines overexpressing OsPYL3 were hypersensitive to ABA suggesting ABA signaling pathway-dependent molecular response of the OsPYL3. Further, constitutive overexpression of OsPYL3 in Arabidopsis led to improved cold and drought stress tolerance. Thus, OsPYL3 identified in this study could be a good candidate for genetic improvement of cold and drought stress tolerance of rice and other crop plants.

Physical and Functional Properties of Arrowroot Starch Extrudates

Abstract: Arrowroot starch, a commercially underexploited tuber starch but having potential digestive and medicinal properties, has been subjected to extrusion cooking using a single screw food extruder. Different levels of feed moisture (12%, 14%, and 16%) and extrusion temperatures (140, 150, 160, 170, 180, and 190 degrees C) were used for extrusion. The physical properties--bulk density, true density, porosity, and expansion ratio; functional properties such as water absorption index, water solubility index, oil absorption index, pasting, rheological, and textural properties; and in vitro enzyme digestibility of the extrudates were determined. The expansion ratio of the extrudates ranged from 3.22 to 6.09. The water absorption index (6.52 to 8.85 g gel/g dry sample), water solubility index (15.92% to 41.31%), and oil absorption index (0.50 to 1.70 g/g) were higher for the extrudates in comparison to native starch (1.81 g gel/g dry sample, 1.16% and 0.60 g/g, respectively). The rheological properties, storage modulus, and loss modulus of the gelatinized powdered extrudates were significantly lower (P < 0.05) and these behaved like solutions rather than a paste or a gel. Hardness and toughness were more for the samples extruded at higher feed moisture and lower extrusion temperature, whereas snap force and energy were higher at lower feed moisture and temperature. There was a significant decrease in the percentage digestibility of arrowroot starch (30.07% after 30 min of incubation with the enzyme) after extrusion (25.27% to 30.56%). Extrusion cooking of arrowroot starch resulted in products with very good expansion, color, and lower digestibility, which can be exploited for its potential use as a snack food.

Physicochemical and Functional Properties of Starch from Two Species of Curcuma

Abstract: The properties of starch extracted from two species of Curcuma viz. Curcuma zedoaria and Curcuma malabarica were studied. The starch from C. malabarica tubers was white in color, while that from C. zedoaria was slightly yellowish due to the presence of the yellow pigment, curcumin. The granule size and shape, amylose content and solubility did not show noticeable difference between starches from the two species. Both the starches possess “B” type x‐ray diffraction pattern. Curcuma zedoaria starch showed a lower peak viscosity and swelling volume when compared to C. malabarica starch. The complete removal of curcumin from C. zedoaria starch by alcohol extraction, resulted in an increase in the swelling and viscosity values close to those of C. malabarica starch. The breakdown in viscosity was quite low for both the starches and setback was higher when compared to cassava and sweet potato starches. The experiments showed that Curcuma starch resembles Dioscorea starches in most of its properties. Di...

Alpha-amylase inhibitor changes during processing of sweet potato and taro tubers.

Abstract: Alpha-amylase inhibitor changes during processing of sweet potatoes (Ipomoea batatas) and taro (Colocasia esculenta) indicated that varietal differences profoundly influence the thermal inactivation profile. The alpha-amylase inhibitors of taro were almost totally inactivated during oven drying of the chips at 90 degrees C and 100 degrees C for 24 h, while 0.8-10% activity was retained in sweet potato chips under the same conditions. Relatively better thermal stability was exhibited by the sweet potato amylase inhibitors at lower temperatures (70 and 80 degrees C) as well. Cooking by boiling the tuber pieces in water resulted in retention of 29-59% amylase inhibitor in sweet potato and 11-16% in taro. Microwave baking was a better method for inactivation of amylase inhibitors in these tubers. Flour prepared from the tubers retained only trivial amounts of the inhibitor.