Unmodified cassava starches with high phosphorus content.

Our study was based on the fact that physiological changes in the plant resulting from the growth conditions alter the properties of the starch. An experimental trial was installed with cassava plants in poor phosphorus soil. A part of plants received phosphate fertilization at a level three times higher than the recommended dose, in order to provide high availability of phosphorus in the soil. The plants grew for two years and the starches were isolated at three times in the second vegetative cycle. The starches had A-type X-ray pattern. Starches isolated from cassava plants grown in soils with high phosphorus had increases of more than 100% in the content of bound phosphorus, which caused changes in the size of the granules, amylose, swelling power, solubility, pasting and thermal properties. These results indicate possibilities of increasing the commercial value of native cassava starch due to the expansion of use, considering the range of uses of phosphate starches for food and non-food purposes.

Gelatinized sweet potato starches obtained at different preheating temperatures in a spray dryer.

Native sweet potato starch was gelatinized at temperatures between 57 and 69 °C and then spray dried, to verify the changes caused by this process. The spray dried starch granules initially swelled with the increase in preheating temperature, displaying a larger diameter, but shrank upon colling. There was an increase in the gelatinization temperature and a decrease in the enthalpy change of the spray dried starches relative to those of native starch. Spray dried starch preheating at 69 °C showed highly reduced enthalpy change (80%) and relative crystallinity. Based on the parameters studied, the best preheating temperature was 67 °C. Under this condition, the starch can be applied in more viscous products that require a greater thickness, and with great process yield (65%). This study showed the feasibility of the application of this process to produce sweet potato starches with specific properties for different purposes in the food and non-food industries.

Harvest time optimization leads to the production of native cassava starches with different properties.

The starch market is very diverse and demanding regarding the functional characteristics of the product. However, no technique based on the management of cassava root harvest time has been applied to obtain starches with different properties. Thus, in this study, cassava roots were harvested at different times and the structure and physicochemical properties of their starches were analyzed. Results indicated the time points in the first growth cycle of plants when all parameters associated with root growth were at their highest values. It was also observed that changes in the time of harvest leads to the production of starches with different granule size, crystallinity, and content of amylose and phosphorus, which resulted in changes in the thermal and pasting properties, as well as in the solubility of the starches and swelling power; that is, on the main determinant characteristics for applicability of the starches. Planned agricultural production monitoring, coupled with the analysis of the main starches characteristics for large-scale cassava crops, can provide commercial benefits for both farmers and industry, as it is possible to obtain starches with desired physicochemical characteristics for varied applications.

Effect of spray-drying and extrusion on physicochemical characteristics of sweet potato starch.

This study aimed to understand the physicochemical characteristics of sweet potato starch following spray-drying and extrusion processes for desirable applications. Spray-dried starch showed formation of agglomerates and decreased in average granular size from 16.5 µm of the native starch granules to 14.1 µm. Spray-drying reduced the percentage crystallinity from 25.3 to 22.6% and showed a slight decrease in the molecular weight of amylopectin from 3.1 to 2.6 × 108 g mol-1. In addition, changes in the pasting and gelatinization properties, higher final viscosity (454.4 RVU), and less enthalpy change (8.73 J g-1) were reported after spray-drying. Thus, spray-drying resulted in partially gelatinized starch, which can be selected for making more viscous products. Extruded sweet potato starch displayed an amorphous structure, showed total loss of crystallinity, and significant reduction in molecular weight of amylopectin to 0.41 × 108 g mol-1, reflecting complete gelatinization of starch granules during extrusion. Extruded starch showed significant changes in pasting properties, including a display cold viscosity (9.4 RVU). Therefore, extruded starch was suitable for products that require quick solubility and a low final viscosity. Thus, the spray-drying and extrusion processes produce sweet potato starches with particular characteristics that can be used for different and potential applications in industries.

Chemical composition of potato tubers: the effect of cultivars and growth conditions.

The aim of the study involved evaluating the chemical composition of tubers of five potato cultivars that were grown under the same cultural practices in soils with low, medium, and high availability of phosphorus. The experimental designs corresponded to a randomized block with four replicates. Tuber samples were analyzed in terms of moisture, ash, protein, lipid, total sugar, fiber, starch, and phosphorus contents. The results suggested that increased availability of phosphorus in soil allowed the production of tubers with higher dry matter content, lower total sugar content, and a higher percentage of starch and protein. Hence, the aforementioned parameters constitute important factors corresponding to the nutritional and industrial quality of potatoes. Increased phosphorus availability in soil can promote significant changes in the composition of potato tubers, and thereby in potential uses of tubers.

Cassava derivatives in ice cream formulations: effects on physicochemical, physical and sensory properties.

In the present study, the effects of derivatives of cassava, maltodextrin and bagasse, on the physicochemical, physical and sensory properties of ice creams were investigated. The content of cassava maltodextrin increased significantly the content of carbohydrate and total soluble solids and decreased lipids content. The effect of cassava bagasse was more pronounced than the maltodextrin on physical and sensory parameters. Increased percentage of cassava bagasse in formulation led to decrease of overrun, melting and luminosity, but increased hardness and unfreezable water. Sensory attributes were mainly influenced by cassava bagasse inclusion. The results suggested the potential use of cassava derivatives in ice cream formulations. Ice creams with low percentage of cassava bagasse (1.5) and intermediate values of cassava maltodextrin (3.65%) had good nutritional, technological and sensorial acceptance.

Characterization of banana starches obtained from cultivars grown in Brazil.

The starch market is constantly evolving and studies that provide information about the physical and rheological properties of native starches to meet the diverse demands of the sector are increasingly necessary. In this study starches obtained from five cultivars of banana were analyzed for size and shape of granules, crystallinity, chemical composition, resistant starch, swelling power, solubility, thermal and paste properties. The granules of starch were large (36.58-47.24µm), oval, showed crystallinity pattern type B and the index of crystallinity ranged from 31.94 to 34.06%. The phosphorus content ranged from 0.003 to 0.011%, the amylose ranged from 25.13 to 29.01% and the resistant starch ranged from 65.70 to 80.28%. The starches showed high peak viscosity and breakdown, especially those obtained from 'Nanicão' and 'Grand Naine'. Peak temperature of gelatinization was around 71°C, the enthalpy change (ΔH) ranged from 9.45 to 14.73Jg(-1). The starch from 'Grand Naine' showed higher swelling power (15.19gg(-1)) and the starch from 'Prata-Anã' higher solubility (11.61%). The starches studied are highlighted by their physical and chemical characteristics and may be used in several applications.