The aim of this study was to determine and compare the melting (Tm), glass transition (Tg) and mechanical relaxation (Tα) temperatures of a new waxy cassava starch. Thermal transitions measurements were obtained by Differential Scanning Calorimetry (DSC) and Dynamical Mechanical Thermal Analysis (DMTA). The experimental data showed a high correlation between water volume fraction and melting temperature (Tm) indicating that the Flory-Huggins theory can be used to describe the thermal behavior of this starch. The Tm of waxy cassava starch-water mixes were lower than a waxy corn starch-water reference system, but differences were not statistically significant. The mechanical relaxation temperatures taken at tan δ peaks were found 29-38°C larger than Tg. The Tα and Tg measured for waxy cassava starch exhibited similar properties to the ones of waxy corn starch, implying that waxy cassava starch can be used in food and materials industry.

This research studied the prevention of hydrolytic rancidity during the storage of rice bran stabilized by an extrusion process. A double screw extruder was used, set at 130° C in the barrel and a rotational speed of the screws programmed at 200 RPM. The moisture content of the bran was adjusted at 20%. The treated bran was stored, using two packing methods (with and without vacuum), at two ambient conditions (18° C – 70 % RH and 30° C - 78% RH) for a period of 8 weeks. The content of free fatty acids (FFA) in the rice bran was observed during the storage time period. The extruded treated rice bran stored at 18° C - 70% RH resulted in lower values of FFA in comparison with the values in the bran kept at 30° C - 78% RH. Vacuum packaging showed a significant disadvantage as compared to packaging without vacuum.

Manufactured egg powders can be formulated to produce food products that vary in their properties. The present study aims to determine the effect of egg white content on the physicochemical characteristics and on the functionality and nutritional value of dried whole egg (WE), egg white (W), and an egg yolk/white mixture in a 1:3 ratio (M1:3). These fresh egg products were spray-dried using sucrose—an agent recognized for its effect of protecting the protein in the egg during the drying process. Experiments were conducted in a laboratory-scale spray dryer, operated under controlled conditions, with an air inlet temperature of 120 °C. In the dried products, water activity, water solubility index, color, and pH were affected significantly as a function of the fresh egg component ratio and the added sucrose. The wettability and dispersibility in water of egg powder were improved when sucrose was added to the WE. The water-holding capacity was highest in dried egg white, and higher in the M1:3 mixture without sucrose added than in the WE with 5% sucrose. The results suggest that modifying the ratio of fresh egg yolk to egg white could lend some control over the protein and fat contents of dried egg products and over their functional properties.

A ready-to-eat cereal processed by a twin-screw extrusion was formulated, using flour and bran from a quality protein maize (QPM) variety and a zinc biofortified rice. The effect of variation of the content of bran in the formulation on the physical quality of the extruded product was studied. The maize-rice meal mixtures contained rice and maize bran formulated at two levels, 25 and 30 % of the total; within the bran mixture the rice bran content was formulated at levels ranging from 0 to 10 %. Physical characteristics of the extrudates such as expansion ratio (ER) and crispness work indicator (WC), were determined. The treatments with lower content of rice bran showed a better behavior, in terms of the physical variables. The products with higher ER and lower WC had desirable sensorial characteristics. Analysis of the extrudates confirmed an increased content of Zn, lysine, tryptophan in relation to raw materials.

The extrusion of food for human and animal consumption is a unit operation that includes mixing, shearing, and force to the materials related to the rheological properties of the materials in the extruder. The present work aims to study the rheological behavior of an extruded fish diet incorporating hydrolyzed protein flour (HPF) processed by extrusion. The measurement was carried out online with a slit die rheometer, defining the rheological models and parameters that fit the process. During the extrusion process, the raw materials used were hydrolyzed protein flour, fish meal, and cassava starch. For the results, the evaluated treatments were adjusted to the Power Law, where an increase in the shear rate decreases the viscosity of the material, corresponding to a pseudoplastic behavior. The incorporation of hydrolyzed protein flour presented a significant effect on the value of n and K_lp, increasing the viscosity with the increase in the percentage of inclusion of HPF. The models obtained for the prediction of the viscosity are adjusted to the system’s changes in shear rate, temperature, and humidity. The importance of the study lies in the fact that the diet developed can be applied to feed fish, and production is currently being scaled up to pilot plants for direct use by some producer communities.

Promoting food security in Latin-America and the Caribbean is directly related to agricultural products. The region faces a food crisis which has reduced large population groups' access to food. This work contributes to the study of obtaining precooked composite flour made from biofortified crops using protein, vitamin A and/or minerals. This study evaluated the effect of precooked flour's composition and precooking on its solubility in water, water absorption capacity, consistency and viscosity; such flour was obtained by extrusion and drying on rollers. The composite flours were obtained from cassava roots, sweet potato tubers, corn, rice and bean grains and cassava leaves. Four composite flours were formulated taking four- to six-year-old children's daily nutrient requirements (protein, iron, zinc and beta-carotenes) as a basis. The extruder was operated at 90^oC, 300 rpm screw rotation speed, 17.64 g/min feed flow, with 30% moisture mixture. The dryer rollers were operated at 4 rpm roller rotation speed, 90^oC surface temperature and 1 mm separation between rollers. It was determined that flour dried on rollers led to more complete cooking and modified starch granule structure than precooking by extrusion, thereby producing flour having greater solubility in water, less water absorption, higher consistency and smaller viscosity, comparable to that of pattern flour. La promoción de la seguridad alimentaria en América Latina y el Caribe está directamente relacionada con los productos agrícolas. La región enfrenta una crisis alimentaria que ha reducido el acceso a los alimentos a amplios grupos poblacionales. Este trabajo contribuyó al desarrollo de harinas compuestas precocidas utilizando seis cultivos biofortificados en proteína, vitamina A o minerales. Se evaluó el efecto de la composición de la harina y el proceso de precocción sobre la solubilidad en agua, capacidad de absorción de agua, consistencia y viscosidad de harinas precocidas obtenidas mediante los procesos de extrusión y secado en rodillos. Las harinas compuestas fueron obtenidas a partir de: raíces de yuca, tubérculos de batata, granos de maíz, arroz y fríjol, y lámina foliar de yuca. Fueron formuladas cuatro harinas compuestas con base en los requerimientos diarios de nutrientes (proteína, hierro, zinc y betacarotenos) para niños de 4 a 6 años. El extrusor fue operado a una temperatura de 90ºC, velocidad de giro del tornillo: 300 r.p.m., flujo de alimentación: 17,64 g/min y humedad de la mezcla: 30%. El secador de rodillos fue operado a una velocidad de giro de los rodillos de 4 r.p.m., temperatura de superficie 90ºC y separación entre rodillos 1 mm. Se determinó que las harinas secadas en rodillos producen mayor grado de cocción y modificación de la estructura de los gránulos de almidón que la precocción por extrusión, obteniéndose harinas de mayor solubilidad en agua, menor absorción de agua, mayor consistencia y menor viscosidad, las cuales fueron comparables con las harinas patrón.