The stability of vitamin A in fortified palm olein during extended storage and thermal treatment

The stability of vitamin A in Refined Bleached Deodorised Palm Olein (RBDPOL) was studied for 24 months. Vitamin A decreased with time, temperature and thermal treatment (frying/cooking). RBDPOL fortification was observed over several temperature ranges, using PET, nylon and HDPE commercial packaging materials. After 24 months, the following vitamin A contents of 39–43 IU g^?1 (39–45%) at 16–20 °C; 35–40 IU g^?1 (43–49%) at 24–29 °C; and 28–39 IU g^?1 (45–73%) at 24–45 °C were detected at the respective temperature ranges. Results showed stability of vitamin A fortified RBDPOL vegetable oil was not stable over typical shelf life (12 months). Depletion of vitamin A accelerated when the RBDPOL vegetable oil was subjected to high temperature thermal treatment.     

Direct contact thermal energy storage system using Na2CO3·10H2O solution

The volumetric coefficient of heat transfer and the energy storage capacity in a direct contact thermal energy storage system using Na₂CO₃·10H₂O solution as thermal energy storage medium have been investigated. Hot kerosene was used as a heat transfer fluid. The experiments were carried out by bubbling hot kerosene from the bottom of a column containing Na₂CO₃·10H₂O solution. The column used in this experiment was made from glass of 3 mm in thickness with the inside diameter of 7 cm and 100 cm in height. The effects of kerosene flow rate and kerosene bubble diameter to the volumetric coefficient of heat transfer and the storing rate of energy have been studied. The volumetric coefficient of heat transfer was strongly affected by the flow rate of the kerosene. The effect of the kerosene flow rate on the storing rate of energy was relatively high, while the effect of the bubble diameter was small.     

Concentration difference heat pump using fusion and freezing processes

This study investigates the possibility of a new method to generate a cold fluid. The method is a concentration difference heat pump using fusion and freezing processes that consist of a cold fluid generating process and a separation process. The operation at the capacity of one ton refrigeration (3.52 kW) has been investigated in this study. In the cold fluid generating process, ice at 0°C was fused into an aqueous solution of NaCl at 0°C, such that the temperature and the concentration of salt of the solution decrease. This dilute solution at a lower temperature was used to generate a cold fluid. The lowest attainable temperature of the solution has been investigated experimentally, and also calculated from the energy balance equation. The calculated results were in good agreement with the experimental results. The decreasing rates of the temperature have also been studied.The dilute solution was then sent from the cold fluid generating process to the separation process and concentrated by membrane distillation. Microtext membrane has been investigated to concentrate the dilute solution. The permeate flux was affected by the temperature, concentration, and pressure of the solution. Experimental results showed that good quality water was obtained from the separation process using membrane distillation.     

Determination of cost-effective operating condition for CO2 capturing using 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid

1-Butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) ionic liquid (IL) is considered for CO₂ capturing in a typical absorption/stripper process. The use of ionic liquids is considered to be cost-effective because it requires less energy for solvent recovery compared to other conventional processes. A mathematical model was developed for the process based on Peng-Robinson (PR) equation of state (EoS). The model was validated with experimental data for CO₂ solubility in [BMIM][BF4]. The model is utilized to study the sorbent effect and energy demand for selected operating pressure at specific CO₂ capturing rates. The energy demand is expressed by the vapor-liquid equilibrium temperature necessary to remove the captured CO₂ from the spent solvent in the regeneration step. It is found that low recovery temperature can be achieved at specific pressure combination for the absorber/stripper units. In fact, the temperature requirement is less than that required by the typical monoethanolamine (MEA) solvent. The effect of the CO₂ loading in the sorbent stream on the process performance is also examined.     

Bacillus cereus strain 10-L-2 produces two arylamine N-acetyltransferases that transform 4-phenylenediamine into 4-aminoacetanilide

A bacterium, strain 10-L-2, that was isolated from soil and identified as Bacillus cereus grew well on medium containing 4-phenylenediamine and Polypepton. Strain 10-L-2 converted a wide variety of anilines, including 4-phenylenediamine, to their corresponding acetanilides. Growing cells acetylated a single amino group of 4-phenylenediamine to form 4-aminoacetanilide with a 97% molar yield, as shown by mass spectrometry and HPLC. Cell extracts exhibited arylamine N-acetyltransferase (NAT) activity toward 4-phenylenediamine. Two NATs, namely, NAT-a and NAT-b, were separated by DE52 column chromatography and were further purified and characterized. The subunit molecular masses of NAT-a and NAT-b were 31.0 and 27.5 kDa, respectively, as determined by SDS-PAGE analysis. The two enzymes had similar pH- and thermo-stabilities and were similarly affected by pH, temperature, and several reagents. The enzymes showed peak activity toward 5-aminosalicylic acid of the substrates tested, but they differed in substrate specificity. Only NAT-a had activity toward sulfamethazine. Although other wild-type bacterial cultures also synthesize NAT, the ability of strain 10-L-2 to convert and detoxify 4-phenylenediamine is much higher. This report provides the first evidence of two NATs in a eubacterium.     

Solubility of CO2 in deep eutectic solvents: Experiments and modelling using the Peng–Robinson equation of state

Carbon dioxide capture and sequestration is drawing increasing attention as a potential method for controlling greenhouse gas emissions. Low cost ionic liquid analogues, namely, deep eutectic solvents (DESs), have attracted more attention for use in a diversity of applications. DESs exhibit many favourable properties, such as availability, non-toxicity, biodegradability, recyclability, non-flammability, and low price.     

Microbial transformation of aniline derivatives: regioselective biotransformation and detoxification of 2-phenylenediamine by Bacillus cereus strain PDa-1

A bacterial isolate, strain PDa-1, grew well on basal medium supplemented with 2-phenylenediamine, sucrose, and ammonium nitrate and completely transformed 2-phenylenediamine. The isolate was identified as Bacillus cereus. The product formed from 2-phenylenediamine was identified by EI-MS and NMR as 2-aminoacetanilide; whole cells converted 2-phenylenediamine to the product with a 76% molar yield. Whole cells also showed a broad substrate specificity toward 20 of 26 tested arylamines with substituent groups of various size and positions. Especially 2-aminobenzoic acid, 4-aminosalicylic acid, 5-aminosalicylic acid, and 2-aminofluorene were converted completely to the corresponding product with an aminoacetyl group. Cell extracts of strain PDa-1 had a high arylamine N-acetyltransferase activity. The partially purified enzyme converted 2-phenylenediamine to 2-aminoacetanilide. Strain PDa-1 constitutively expressed the enzyme in the absence of 2-phenylenediamine. Effects of 2-phenylenediamine and 2-aminoacetanilide on growth indicated that this enzyme probably plays a role in the detoxification of toxic arylamines in this strain.