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Cassava or tapioca (Manihot esculenta Crantz) tubers having high amount of carbohydrate are utilized after boiling or processing into starch and flour. Textural properties of raw and cooked tubers depend on variety, maturity, growing environment, physico-chemical and starch properties. Starch is used in food preparations as gelling and thickening agent, stabilizer and texture modifier. This study aims at analyzing and modeling the textural, dynamic rheological and gelatinization properties of selected cassava varieties. The thermal softening behavior was analyzed by linear regression and fractional conversion techniques, rheological properties of the gelated starch by Maxwell and power law models. The varieties were classified based on their physico-chemical, texture profile, rheological and gelatinization properties by multivariate analysis. The textural, rheological and gelatinization properties were significantly affected by the varieties (p<0.05). Thermal softening of tubers was modeled by dual mechanism first order kinetic model with rate constant values ranging from 0.081 to 0.105 min −1 . Linear regression models with extremely good fit were obtained to explain the relationship between the degree of cooking and relative firmness. The dynamic spectra of the gelated starch showed the characteristics of concentrated biopolymer dispersion and described using Maxwell and power law model. The results showed that textural, rheological and gelatinization properties varied considerably among the varieties and besides the physico-chemical properties, interaction between them and structural make up of the tuber parenchyma had a great influence on cooking quality and rheological properties.

Cassava mosaic disease (CMD) is the most serious disease in cassava-in India where it is grown for food, starch and sago purpose. The disease is best kept under control by exploiting the available host plant resistance, which was introgressed from M. glaziovii to cassava and it is known to be polygenic control. In the present study, an attempt was made to construct the genetic linkage map of cassava using SSR markers with the objective of mapping genes associated with CMD. Using single marker analysis (SMA), four CMD resistance markers were detected viz. SSRY28, SSRY235, SSRY44 and NS136. SSRY28 and SSRY235 were located on linkage group G and SSRY44 and NS136 on linkage group P of cassava genetic map developed by Fregene et al. (1997). Among the four markers, three (SSRY235, SSRY44 and NS136) are new markers associated with CMD resistance. The detection of markers SSRY44 and NS136 having association with CMD resistance is a new report indicating the possibility of having another genetic loci for CMD resistance in cassava in addition to the already established on linkage group G. This finding supports the polygenic control of CMD resistance.

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Storage proteins in plants, because of high nutrient value, have been a subject of intensive investigation. These proteins are synthesized de novo in the cytoplasm and transported to the storage organelles where they serve as reservoir of energy and supplement of nitrogen during rapid growth and development. Sweetpotato is the seventh most important food crop worldwide, and has a significant contribution to the source of nutrition, albeit with low protein content. To determine the behaviour of seed storage proteins in non-native system, a seed albumin, AmA1, was overexpressed in sweetpotato with an additional aim of improving nutritional quality of tuber proteins. Introduction of AmA1 imparted an increase in protein and amino acid contents as well as the phytophenols. The proteometabolomics analysis revealed a rebalancing of the proteome, with no significant effects on the global metabolome profile of the transgenic tubers. Additionally, the slower degradation of starch and cellulose in transgenic tubers, led to increased post-harvest durability. Present study provides a new insight into the role of a seed storage protein in the modulation of photoassimilate movement and nutrient acquisition.