Authors:Abbas Al-Hdabi, Mohammed K. Fakhraldin, Rasha A. Al-Fatlawy, and Tawfek Sheer Ali
will play a vital role as a cementitious material due to the high concentration of lime and gelignite. On the other hand, because of the problems, which are occurred in the subbase layer in roads and buildings in Iraq, many ways can be adopted to
The analyzed samples were runoff waters from bituminous roofing. The runoff water pH was lower than that of the storm-water. First flush phenomena were observable in the samples conductivity, turbidity as well as suspended solid, dry and organic matter concentration. The reason of the phenomena is the initial dissolution of deposited aerosols and weathering products. Because of that, the roof runoff quality is affected by the dry period length. Presumably to the roof matter, the samples had high dissolved organic matter concentrations. The measured polycyclic aromatic hydrocarbon (PAH) concentration implied the dissolution of some component from the roof matter.
The objective of this work was to assess the impact of various NaCl concentrations on Lactobacillus rhamnosus OXY viability after freeze-drying. Osmotic stress was applied during the exponential growth phase of bacterial culture. At salt concentrations between 0.2–0.5 M, a high biomass concentration and a significant increase in cell viability after lyophilisation was observed. An analysis of two-dimensional protein gels indicated the presence of shock proteins, for example, GroEL, ClpB, DnaK, TF, which provide resistance during freeze-drying and subsequent storage. On the basis of these results, it is recommended that lactic acid bacteria cultures be sub-lethally treated with 0.5 M NaCl before freeze-drying.
The degradation process of fructo-oligosaccharides (Raftilose® P95) has been studied in apple pulp matrix at 70–80 °C in pH range 2.7–3.3. Changes of sugar compositions have been analysed by an appropriate isocratic HPLC with differential refractive index detector for oligosaccharide determination. According to Arrhenius equation significant effect of temperature has been observed on the decrease of oligomer concentration. The oligomers (DP3-DP7) degrade continuously at any pH between 2.7 and 3.3. The lower the pH the higher the change of oligomer and monomer concentration is. The oligomers (DP4-DP7) could give out in 30–40 min below pH 3.0 caused by the high concentration of protons. The rate of degradation depends not only on the processing time, temperature, and the proton concentration of the solution, but on the characteristic of apple pulp, too, where the degradation is significantly higher than that in water solution.
Authors:D. Varga, Zs. Sándor, Cs. Hancz, I. Csengeri, Zs. Jeney, and Zs. Papp
The aim of our study was to survey the geosmin (GSM) and 2-methylisoborneol (MIB) concentrations of the sediment and that of common carp (Cyprinus carpio) flesh in three different Hungarian fish farms (clayey, marshy, and sodic ponds).
Results showed that the concentrations of off-flavour compounds of the sediment and fish fillets were related to the natural environment. The GSM concentration of bottom soil samples was higher, than MIB in each fish farm. Both off-flavour compounds were the highest in the marshy fish pond and the lowest in the sodic pond. In case of fish flesh, significant differences were found between the farms in GSM level and fat content. In the fish flesh the same tendency was found as in the sediments, but surprisingly, MIB concentration was higher in the fillets, referring to accumulation.
Changes of volatile compounds of noni juice during the traditional process of fermentation/aging was studied by means of HS-SPME and GC-MS. Major acids, octanoic and hexanoic, diminished their concentration; while esters of ethanol, 1-butanol and 1-hexanol, with their flavour fruity notes, increased. The concentration of esters of methanol and 3-methyl-3-buten-1-ol decreased during the fermentation/aging process, whereas major alcohols of noni juice, 1-hexanol and 1-octanol, increased their concentration during the process. During the 60 days of the process the volatile composition of the noni juice had reached stability. These chemical changes justify that fermented juice possesses a flavour less pungent than fresh juice due to an important decrease in the hexanoic and octanoic contents, as well as a greater fruity note due to the increment in ester concentrations.
Authors:K.G. Mladenović, M.Ž. Muruzović, and L.R. Čomić
In this study, the effects of different temperature, pH, salt and glucose concentrations on the planktonic growth, biofilm formation, and formed biofilm of Serratia odorifera and Serratia marcescens, isolated from traditionally made cheese, were investigated using spectrophotometric method. The investigated strains demonstrated best planktonic growth and biofilm formation in Tryptic soy broth. The limiting factors for the planktonic growth and biofilm formation were temperature below 4 °C and salt concentration above 4%. Temperature of 37 °C and 44 °C, as well as various concentrations of glucose, stimulated the planktonic growth of bacteria. Moderate influence on biofilm formation was demonstrated at 37 °C as well as at various concentrations of glucose. These results were in accordance with the origin of bacteria, since the isolates were obtained from cheese.
The adaptation to brining conditions of 20 strains of Lactobacilli were tested. At 6% salt all strains reduced the pH to 4 in 72 h. At higher salt concentration, only some of the strains showed this ability. The ability to synthesise lactic acid was tested at different salt concentrations. Lactic acid was quantified by HPLC analyses and at halophilic conditions six strains showed good ability. The glucosidic activity tested on a synthetic compound (
-nitrophenyl-β-D-glucopyranoside) screened the best
strains (20205 DSMZ, 20314 DSMZ and 104442 CIP). The ability to hydrolyse the oleuropein molecule was tested and all of the strains selected showed good activity at low salt concentration and low oleuropein content in the medium. This ability decreased drastically when the salt and oleuropein content were higher. The best strain was the 20205 DSMZ, which at low salt concentration hydrolysed more than 95% of oleuropein in 120 h.
The protein content, solubility and functional properties of a total protein concentrate prepared from the seeds of
Roxb. were determined. The effects of pH and/or NaCl concentration on some of these functional properties were also investigated. The protein content of the seed protein concentrate was found to be 65.88%. The minimal protein solubility was observed at pH 4 and the maximum was at pH 12. Water- and oil-holding capacities of the seed protein concentrate were 2.77 g g
and 5.79 g g
, respectively. The emulsifying activity and emulsion stability, as well as foaming capacity and foam stability, were greatly affected by pH levels and salt concentrations. Lower values were observed at slightly acidic pH (pH 4.0) and high salt concentration. Total protein concentrate was highly viscous which depends on concentration and pH levels. The lowest gelation concentration of seed protein concentrate was found to be 14% and 8% when the proteins were dissolved in distilled water and 0.5 M or 1 M NaCl solution, respectively.
Single screw extrusion of cassava starch was evaluated as a pre-treatment for the enzymatic hydrolysis of the extrudate and fermentation to yield alcohol. The acid concentration, barrel temperature and moisture content showed that all the variables were significant. Increasing acid concentration or barrel temperature induced starch depolymerisation with a higher water solubility index and lower water absorption index. At 20 and 24% moisture contents the cold paste viscosity decreased. As a result of the addition of acid during extrusion cooking the degree of starch hydrolysis resulted in low hot paste viscosity. Acid concentration was significant in the production of reducing sugars. At concentrations above 0.024 N, as the temperature increased, the reducing sugar content also increased. Nevertheless, at concentrations below 0.024 N, the reducing sugar content showed the opposite result. The best yield of alcohol obtained from the extruded starch was 98.7% (0.56 g of ethanol/g starch), which, on average, was 5.7% and 6.8% higher than that obtained from starch extruded without acid and from starch gelatinized by the conventional method, respectively.