EFFECTS of THERMAL TREATMENTS ON TEXTURE of SOY PROTEIN ISOLATE TOFU

Effects of three thermal treatments; boiling at 100C and retorting at 110 and 121C, on texture of soy protein isolate tofu were studied for a range of heating times. Retorted tofu showed a shrinkage of 18–25% of its original size and a loss of 6–12% of its original moisture. Tofu processed at high temperatures and long heating times developed higher values of texture profile parameters than tofu processed at lower temperature and shorter heating times. the thermal treatment of tofu at elevated conditions also caused an increase in sensory hardness and a decrease in moistness and overall acceptability of the tofu. the increase in texture profile values appeared to be mirrored by a decrease in protein solubility in 1% sodium dodecyl sulfate solvent and a reduction in moisture content of the tofu. the formation of disulfides linkages at elevated temperatures and during heating at 100C stabilized protein aggregates that were initially formed by hydrophobic interactions. Formation of the disulfides and shrinkage of tofu as a result of moisture loss were suggested as the major reason for decreased sensory values of thermally processed soy protein isolate tofu.     

Analysis of pollutant removal effect using innovative ridge2shaped constructed wetland

In t his paper, a new t ype of ridg e2shaped co nstr ucted w etland w hich combines surface flow and ho rizontal subsurface flow w as proposed. The pro po sed wetland had simple str ucture, low co nstr uction and operating cost, less human interference and go od po llution remov al effect. T he combination of surface flow and subsurface flow pr ov ided an aero bic and anaerobic alter nating env iro nment for the entir e w etland. The performance of the proposed wetland was compared with a traditional horizontal subsurface flow wetland. The comparison results showed that the removal rates of BOD ( biochemical ox ygen demand) , T N ( t otal nitr ogen) , and T P ( tota l phospho rus) in the ridge2shaped w etland in2 creased up to 201 3% , 171 0% , and 91 1% , respectively . The pr oposed w et land structure co uld be w idely applied for t reatment of rur al and urban domest ic sew age pollutio n o r ag ricultural po int and no npo int so ur ce water po llut ion.     

OPTIMUM CASH-FLOW SCHEDULING OF CONSTRUCTION PROJECTS

In progress-payment contracts, the contractor is paid for the work performed based on progress reports made at specified intervals. The owner holds back a percentage of the payments until the project is completed. The optimal project schedule is dictated by the schedule of the project incomes and costs. In this paper, a mixed-integer optimization model that maximizes the contractor's profit for progress-payment contracts is developed. Other scheduling objectives such as levelling the overdraft and minimizing the maximum overdraft are formulated. Constraints related to network precedence, budget limitations, and required available total floats are incorporated in the model. The model can be used to examine the sensitivity of the profit to different progress report intervals and different interest rates. The flexibility of the model to accommodate other practical situations is discussed.     

COD (GADUS MORHUA) TRYPSIN HEAT INACTIVATION: A REACTION KINETICS STUDY

The heat inactivation of cod (Gadus morhua) trypsin was examined at 40–55C by nonlinear regression (NLR) analysis according to 1st-order, n-th order, or consecutive reaction kinetics. At 40C Cod trypsin was inactivated by a 2nd-order reaction; n = 2 (±0.014) with a pseudo rate constant (k′) of 6.46 (±0.04) × 10^?4 (s^?1). The order of reaction decreased with increasing temperature; n = 1.54 (±0.003) at 45C, n = 0.8 (±0.005) at 50C or n = 0.64 (±0.014) at 55C. At 45–55C the consecutive model also indicated 1st-order inactivation kinetics. SDS-PAGE analysis showed that with progressive heating the concentration of cod trypsin decreased and there was an appearance of lower molecular weight polypeptides. The results are consistent with a heat inactivation process involving trypsin autolysis. A mechanism for cod trypsin heat inactivation is proposed which accounts for the observed 1st-order or 2nd-order reaction kinetics as limiting cases.     

Antibacterial activities and corrosion behavior of novel PEO/nanostructured ZrO2 coating on Mg alloy

Plasma electrolytic oxidation (PEO) was developed as a bond coat for air plasma sprayed (APS) nanostructure ZrO₂ as top coat to enhance the corrosion resistance and antibacterial activity of Mg alloy. Corrosion behavior and antibacterial activities of coated and uncoated samples were assessed by electrochemical tests and agar diffusion method toward Escherichia coli (E. coli) bacterial pathogens, respectively. The lowest corrosion current density and the highest charge transfer resistance, phase angle and impedance modulus were observed for PEO/nano-ZrO₂ coated sample compared with those of PEO coated and bare Mg alloys. Nano-ZrO₂ top coat which has completely sealed PEO bond coat is able to considerably delay aggressive ions transportation towards Mg alloy surface and significantly enhances corrosion resistance of Mg alloy in simulated body fluid (SBF) solution. Moreover, higher antibacterial activity was also observed in PEO/nano-ZrO₂ coating against bacterial strains than that of the PEO coated and bare Mg alloys. This observation was attributed to the presence of ZrO₂ nanoparticles which decelerate E. coli growth as a result of E. coli membranes.     

Review: Studies on the reproductive and developmental biology of <I>Cichlasoma dimerus</I> (Percifomes,Cichlidae)

Many characteristics of the South American teleost fish Cichlasoma dimerus (body size, easy breeding, undemanding maintenance) make it amenable to laboratory studies. In the last years, many of the fundamental aspects of its reproductive and developmental biology have been addressed in our laboratory. Rather recently, the immunohistochemical localization of pituitary hormones involved in reproduction and in background color adaptation has been described in both adult and developing individuals, and the role of FSH in ovarian differentiation has been established. These findings have been correlated with mapping of some of their brain-derived controlling hormones. The latter include brain-derived gonadotropins which were shown to be active in vitro in the control of pituitary hormone secretions. The emerging picture shows C. dimerus as an interesting species in which many of their basic features have already been investigated and which conform a solid platform for comparative studies correlating neurohormones, pituitary hormones and behavior, from the molecular to the organismic level.