Precooked Corn Flour for Venezuelan Arepa Preparation: Characterization of Particle Size Fractions

Commercial precooked corn flour (used for Venezuelan arepa preparation) was sieved into fractions using a Ro-tap shaker. Particles 297 μm thick had the highest consistency. Particles 354 μm thick had the longest stability, their yellow color value (Hunter) was the smallest, and arepas made from them had the highest elasticity. Sedimented volumes were greater for particles 297 μm thick and coarser. Functional properties, evaluated by trained judges, were better for fractions with sizes between 297 and 420 μm. Regression analysis showed that particles between these sizes are the best suited for Venezuelan arepa preparation.     

Communication contention in APN list scheduling algorithm

Task scheduling is an essential aspect of parallel process system. This NP-hard problem assumes fully connected homogeneous processors and ignores contention on the communication links. However, as arbitrary processor network (APN), communication contention has a strong influence on the execution time of a parallel application. This paper investigates the incorporation of contention awareness into task scheduling. The innovation is the idea of dynamically scheduling edges to links, for which we use the earliest finish communication time search algorithm based on shortest-path search method. The other novel idea proposed in this paper is scheduling priority based on recursive rank computation on heterogeneous arbitrary processor network. In the end, to reduce time complexity of algorithm, a parallel algorithm is proposed and speedup O(PPE) is achieved. The comparison study, based on both randomly generated graphs and the graphs of some real applications, shows that our scheduling algorithm significantly surpasses classic and static communication contention awareness algorithm, especially for high data transmission rate parallel application. Supported by the National Natural Science Foundation of China (Grant Nos. 90715029 and 60603053), the Cultivation Fund of the Key Scientific and Technical Innovation Project, Ministry of Edacation of China, and the Key Project of Science & Technology of Hunan Province (Grant No. 2006GK2006)     

Proton NMR and Dielectric Measurements on Sucrose Filled Agar Gels and Starch Pastes

Low-field proton NMR and high-frequency dielectric measurements were performed on sucrose-filled agar gels of 0 to 1.2g sucrose/g water and starch pastes of concentrations between 0.2 and lg starch/ g water. The dielectric constant decreased linearly with increasing concentration for both. The dielectric loss of sucrose-filled agar gels showed two regions, first increasing and then decreasing with concentration. The dielectric loss data for starch pastes showed a constant value close to that of pure water throughout the concentration range. Dielectric data were related to hydration models derived from proton NMR measurements.     

Some Functional and Utilization Characteristics of Sesame Flour and Proteins

Sesame defatted flour was prepared from dehulled seeds and the proteins extracted by isoelectric precipitation from an alkaline suspension of the flour. Temperature and pH effects on viscosity of a protein dispersion were measured using a Brookfield viscometer. Emulsifying capacity and emulsion stability were measured in mayonnaise and meat-type emulsions, respectively. Sesame flour was texturized by a simple method to produce a ground meat-like product with a hydration capacity of 380–440%. Sensory evaluation of meat loaves with 0–40% meat replaced by hydrated textured defatted sesame flour indicated no significant difference between samples. Viscosity of sesame protein dispersions at 90°C increased with increasing pH. The proteins did not form a self-supporting gel. Their emulsifying capacity proved to be relatively high when compared with traditional proteins.     

Water Associated with Whey Protein Investigated by Pulsed NMR

Proton longitudinal relaxation rates were determined for whey protein powders and suspensions of solids concentration between 0.01 and 2.0 g solids/g water. Data showed three hydration regions. The relationship between relaxation rate and solids content was investigated for each region. The two-state model with fast exchange was applied to the dilute suspensions and the high-solids regions. This allowed identification of polymer water and free water states in dilute suspensions and also identification of polymer water and capillary water in high-solids preparations. For intermediate-solids mixtures the two-state model was extended to three water states: polymer, capillary and free. These models enabled calculation of the amount of each water state associated with whey protein at a given moisture content.     

Microwave Heating of Agar Gels Containing Sucrose

A mathematical model was developed for predicting the temperature profiles of cylindrical samples of sucrose containing agar gels heated by microwaves. Temperature was modeled in terms of dielectric properties of gels and the power absorbed by the sample. Experimental corroboration of the predicted temperatures was obtained by microwave heating cylindrical gels of 2% agar containing 0, 40, and 60% sucrose. The levels of sucrose in the gels notably affected the temperature profiles in the cylinders. Samples with no sucrose showed a pronounced central heating effect, 40% sucrose samples showed a early uniform heating profile and 60% sucrose samples showed surface heating.