Microstructure of Selected Binary Food Powder Mixtures

Binary mixtures of sugar, citric acid, malic acid, soy protein and starch, after exposure to various relative humidities, were analyzed by Scanning Electron Microscopy (SEM). It is shown that depending on interparticle surfaceaffinity, concentration and relative humidity, the mixtures could be random, partially random, ordered or partially ordered. The type of bridging, between the aggregated particles depended on their chemical species and the availability of surface moisture.     

Zinc and Phytate Distribution in Peas. Influence of Heat Treatment, Germination, pH, Substrate, and Phosphorus on Pea Phytate and Phytase

The largest proportions of zinc and phytate, 88.7 and 97.1%, respectively, were in the Garfield pea cotyledon; the greatest concentrations were in the germ. Cooking peas by two different methods resulted in 13% phytate reduction. Peas incubated 6.5 hr from 25 to 80°C yielded maximum phytate loss (25%) at 60°C due to phytase activated hydrolysis. Germination (10 d) decreased pea phytate 75% and increased phytase activity 12-fold. Semi-purified germinated pea phytase showed temperature optimum at 45°C, pH optimum of 5.2, 30% inhibition by 1 mM inorganic P, and substrate preference for pyrophosphate. Incubation of early germinated peas at optima pH and temperature is suggested for maximum phytate reduction.     

Oxygen consumption by portal-drained viscera of cattle: comparison of analytical methods and relationship to whole body oxygen consumption

Two experiments were conducted to compare methods of determining oxygen consumption by portal-drained viscera and to relate this consumption to total oxygen consumption by lactating dairy cows. Oxygen consumption was the product of portal blood flow (determined by dilution of dye infused into a mesenteric vein) and portal-arterial concentration differences of oxygen. In Experiment 1, portal-arterial concentrations of oxygen were determined in samples from three cows using equations based on blood pH, hemoglobin, partial pressure of carbon dioxide, and partial pressure of oxygen (method 1) or by direct oxygen determination with an oximeter (method 2). Overall, there were no differences in oxygen concentrations or oxygen consumption by portal-drained viscera between methods. In Experiment 2, oxygen consumption by portal-drained viscera (method 2) and total oxygen consumption were measured in two lactating cows. Oxygen consumption by portal-drained viscera accounted for 18% of total oxygen consumption.     

The effects of stress and crack morphology on time-of-flight diffraction signals

A model based on the theory of infinite contacting surfaces is used to analyse the transmission and reflection of ultrasound at tight fatigue cracks under compressive stress. The model developed is valid for both compression and shear (SV) waves incident at arbitrary angles on a fatigue crack and includes mode conversion effects. In discussing diffraction of ultrasound by the tips of finite length fatigue cracks, we associate the amplitude of the diffracted signal with the strength of the signal reflected from cracks of infinite extent. Thus we allow all the energy transmitted by the tight crack to play no part in the diffraction process. Comparison is made with experiments carried out at Harwell and we conclude that, for these particular experiments, the cracks are fully open when subjected to about 88 MPa of tension, and that the experimental results are consistent with a root mean square deviation from flatness of the crack faces of about 1·5 μm. This is in broad agreement with the actual crack profile when a sampling length of about 30 μm is used. Using these values the theory and experiment show excellent agreement to within 2 dB over the whole applied stress range. The results show, for example, a diffraction signal decreased by a maximum of about 13 dB when the applied compressive load corresponds to 70% of the maximum load used during crack growth. Similar conclusions are also drawn for conventional pulse-echo inspection, whereas Tandem suffers a greater reduction in signal strength due to the usually lower frequency.     

Automated fluorimetry in quality control of pasteurized and ultra-high temperature-treated starch soup

Automated monitoring of the microbiological quality of heat-processed foods by the resazurin reduction test was applied to microtitration plate incubator-fluorimeter technology. The appearance and disappearance of the fluorescing peak of resorufin was monitored on microtitration trays. Pasteurized or ultra-high temperature-treated starch-based soup was used as the model food system. Bacillus subtilis spores (ultra-high temperature treatment) and vegetative cells of Enterococcus faecalis (pasteurization) were inoculated into the soup before the heat treatment at levels which resulted in some survival. The timing of appearance of maximum fluorescence correlated with the number of bacteria in pre-incubated samples. Automated resazurin-reduction fluorimetry was compared with conventional plating, turbidometry and microcolony count by the direct epifluorescent filter technique. The results of the resazurin test correlated well with those of all the other methods tested. Fluorimetry had the advantage that the results could be read within 1–5h and the reproducibility was superior to the other methods.     

Wastewater treatment in tsunami affected areas of Thailand by constructed wetlands.

The tsunami of December 2004 destroyed infrastructure in many coastal areas in South-East Asia. In January 2005, the Danish Government gave a tsunami relief grant to Thailand to re-establish the wastewater management services in some of the areas affected by the tsunami. This paper describes the systems which have been built at three locations: (a) Baan Pru Teau: A newly-built township for tsunami victims which was constructed with the contribution of the Thai Red Cross. Conventional septic tanks were installed for the treatment of blackwater from each household and its effluent and grey water (40 m3/day) are collected and treated at a 220 m2 subsurface flow constructed wetland. (b) Koh Phi Phi Don island: A wastewater collection system for the main business and hotel area of the island, a pumping station and a pressure pipe to the treatment facility, a multi-stage constructed wetland system and a system for reuse of treated wastewater. The constructed wetland system (capacity 400 m3/day) consists of vertical flow, horizontal subsurface flow, free water surface flow and pond units. Because the treatment plant is surrounded by resorts, restaurants and shops, the constructed wetland systems are designed with terrains as scenic landscaping. (c) Patong: A 5,000 m2 constructed wetland system has been established to treat polluted water from drainage canals which collect overflow from septic tanks and grey water from residential areas. It is envisaged that these three systems will serve as prototype demonstration systems for appropriate wastewater management in Thailand and other tropical countries.     

Influence of cooking and drying processes at different temperatures on the nutritive value of the protein of mussels (Mytilus edulis)

The effect of steam cooking (96 degrees C for 15 minutes) and drying at two temperatures, 70 degrees C and 110 degrees C, on nutritive value of mussel protein was studied. The measurements were carried out by nitrogen balance techniques in growing rats, and the nutritional parameters studied were: CD, BV and NPU. The crude digestibility (CD) values were: 87 +/- 1 and 82 +/- 1, and the biological values (BV), 80 +/- 1 and 74 +/- 1 for raw mussels, dried at 70 degrees C and at 110 degrees C respectively. This implies a significant decrease in the protein nutritive values of the mussel dried at a higher temperature. Cooking prior to drying significantly improved the digestibility and the biological value of the mussel's protein. In effect, improvement was so great, that the different drying temperatures did not affect the previously cooked product in a different way; therefore, the CD (94 +/- 1 and 94 +/- 1) and the BV (90 +/- 1 and 90 +/- 2) were the same for the mussel's protein, cooked and dried at 70 degrees C or at 110 degrees C.