Advanced Materials Research Vols. 236-238

Abstract: Drying characteristics of crispy winter jujube dried by explosion puffing drying at different vacuum drying temperature were investigated. Selection of the best model was examined by comparing the determination of coefficient (R²), root means square error (RMSE), and mean relative percentage error (P) between the experimental and predicted values. As expected, higher drying rates were obtained with higher vacuum drying temperature. The results showed that the Modified Henderson and Pabis model provided better simulation of drying curves for crispy winter jujube according to thin-layer drying theory. The effective moisture diffusivity of crispy winter jujube dried by explosion puffing drying with higher vacuum drying temperature was higher than the others.

Abstract: The synthesis of oleic acid phytosterol esters catalyzed by Zr(SO₄)₂·4H₂O under free medium was investigated. The reaction conditions were optimized using response surface methods (RSM) measured by the degree of esterification (DE). A quadratic response regression equation of esterification rate on independent variables of temperature, substrate molar ratio (oleic acid: phytosterol), reaction time and catalyst amount was established. Under the optimized reaction conditions, the DE of phytosterol with oleic acid reached 93% and then the phytosterol esters catalyzed in the optimum condition confirmed by the GC and FTIR analysis. It was concluded that the esterification of phytosterols and oleic acid by the green catalyst Zr(SO₄)₂·4H₂O is very efficient and this supplied as an alternative to the green synthesis of phytosterol esters.

Abstract: To evaluate oxidative stability of microencapsulated oils rich in polyunsaturated fatty acids, the change of peroxide value (POV) during storage was investigated. Microencapsulated oils were prepared by spray drying emulsions containing oils rich in docosahexaenoic acid or arachidonic acid, caseinate, modified starch and maltodextrin. Results showed that oxidative stability and initial POV of oils, packing and storage temperature all affected markedly oxidative stability of microencapsulated oils. It is necessary for obtaining stable microencapsulated oils to choose oils of high oxidative stability and low initial POV, reduce oxygen content in wrapper and lower storage temperature. Basing on our findings, six stages of the oxidation of microencapsulated oils were suggested as compared with three stages of the oxidation of oils. It is very important for the oxidative stability and shelf-life to extend the first and the forth stages, shorten the second and the third stages, and avoid the fifth and the sixth stages during oxidation of microencapsulated oils.

Abstract: The N,O-carboxymethyl-chitosan (N,O-CMC) was used to investigate the adsorptions of two metals of Cd(Ⅱ) and Pb(Ⅱ) ions in an mixed aqueous solution. The effects on adsorption capacities such as pH value, temperature, adsorbent dose and initial metal ion concentrations were investigated, and the dialysis method was applied to separate the materials after adsorption. The results revealed that the better adsorption of N,O-CMC for Cd(Ⅱ) and Pb(Ⅱ) ions at the pH 7-8; the effect of temperature on the adsorption was not significant; the absorption of Cd(Ⅱ) and Pb(Ⅱ) ions was enhanced with the increase of N,O-CMC amount; the adsorption capacity increasesed with the addition of the concentration of initial metal ions in the aqueous phase. The adsorption of Pb(Ⅱ) ion in Cd-Pb mixed solution on the N,O-CMC was well followed as the Langmuir isotherm equation under the concentration range studied, and Cd(Ⅱ) ion was corresponding to Langmuir adsorption equation in 100-200 mg/L and 200-500 mg/L, respectively. Conclusion: N,O-CMC was suitable for adsorbent to removal Cd(Ⅱ) and Pb(Ⅱ) ions, but it can selectively adsorption ions from the mixed solution, the adsorption capacity (Qm) for two metal ions was as follows: Pb(Ⅱ) > Cd(Ⅱ).

Abstract: The paper studied the effect of different maceration levels on the antioxidant and bioavailability of wine from vitis vinifera cv. Muscat Hamburg in China. The bioavailability of phenolic fraction was assayed for Folin-Ciocalteu Reaction (FCR) reducing capacity, and methanol content was determined with Gas Chromatography. All maceration treatments raised wine polyphenolic content and antioxidant while increased the methanol, too. Evaluated by an in vitro digestion process, the bioavailability of polyphenolic compounds and methanol in wine showed that the FCR value of the full-maceration samples was the highest (31.56%), the methanol content of the samples was higher than that of other three groups (29.60%), and the availability was up to its maximum absorptivity (53.07%). It suggests that the Muscat red wine may represent higher quality and bioavailability after extended maceration.

Abstract: The optimization of low-alcohol litchi wine brewing process through orthogonal design L₉(3⁴) and the comparison of influence of pre- and post-fermentation on the volatile compounds by using gas chromatography-mass spectrometry (GC–MS) analysis were studied. The low-alcohol litchi wine which fermented using the mixed aroma-producing yeasts Kloeckera apiculata (Y2) and Hansenula anomala (Hansen) H. et P. Sydow (Y4) at 14°C, with ratio Y2/Y4 of 1:2 (vol.) and inoculum size of 4 (%,vol.), had the typical characteristics of low alcohol, light yellow color, fresh litchi-like and refined wine aroma, refreshing sweet taste. The volatile compounds of the fermented wine invented a marked improvement in flavor of the low-alcohol litchi wine, because the esters were increased 1.16-fold, alcohols (0.96-fold), acids (2.38-fold), while the terpenes decreased more than 39% compared with samples before fermentation. The results would explain the technological differences and superiorities in the aroma compounds contributed by the aroma-producing yeasts.

Abstract: The technology on the leaching process of sodium nitrate from nitratine was developed in this work. The effects of leaching duration, solid-to-liquid ratio on the leaching were studied. The results show that the utilizable sodium nitrate leaching ratio from the nitratine reach 90.2%, for leaching duration of 15 minute and at the solid-to-liquid ratio of 1.0 g.g^-1. A new scheme of step-by-step spray is advanced, according to the result of leaching repeatedly, which increased the concentration of lixiviation up to 29.58%( 400g.L^-1) at 25°C. The results reported will be useful for leaching process design and control.

Abstract: The total content of flavonoids of extracts of Apocynum venetum (AV) fibers were determined by UV spectrophotometer. The antimicrobial activities of AV extracts were also tested using agar plate diffusion method. The results showed that the total content of flavonoids of extracts of AV fibers was 0.76 mg/g. The ethanol extract of AV fibers were partitioned by EtOH, n-BuOH and H₂O. Each part was screened for antibacterial activities. The EtOH faction of extract was the most effective against Staphylococcus aureus, Staphyloccus edidernidis, Bacillus lentus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. The fractions of n-BuOH and H₂O did not show any inhibitory effect on the tested bacterial and fungi. The present work is the foundation for further isolating and purifying the bioactive components in AV fibers.

Abstract: The present study was carried out to determine the effect of latrunculin A (Lat-A) and FBS on the developmental potentials of electrically activated porcine oocytes matured in vitro. Electrically activated MII oocytes were incubated for 2 hr in mPZM-3 supplemented either with 0、20 nM、1 μM Lat-A or 2.2 μg/ml cytochalasin B (CB). They were then removed and placed in mPZM-3 with or without 10% FBS (addition) on Day 4 for further development. The nuclear activation rate was significantly improved when activated oocytes were cultured in mPZM-3 with Lat-A (P<0.05). At higher dosage (1μM) of Lat-A, the extrusion of second polar body was inhibited while the cleavage rate increased significantly (P<0.05). Significant interaction between Lat-A and FBS supplementation on Day 4 was observed during in vitro development (P<0.05). The hatched blastocyst rates and cell numbers per blastocyst were significantly enhanced with the supplementation of FBS (P<0.05). The blastocyst formation, hatched blastocyst rates and mean cell numbers per blastocyst of 1 μM Lat-A treatment with FBS supplementation were significantly higher than those of 20 nM Lat-A and CB treatments with FBS supplementation (P<0.05), but the individual effect of FBS supplementation was not observed on blastocyst formation in 20 nM and 1 μM Lat-A treatments. While significant difference was seen in blastocyst formation and cell numbers per blastocyst among all the treatments without FBS supplementation (P<0.05). These results indicate that Lat-A especially at the dosage of 1 μM can significantly improve the developmental potential of electrically activated porcine oocytes, and the FBS supplementation on Day 4 of development have an additional effect on porcine embryo development.

Abstract: Niobium was recovered by acid-alkaline leaching from metallurgial residues. The experimental results indicate that effects of different leaching system and leaching conditions on the Nb recovery were different. Separation of niobium and impurities such as iron, manganese, calcium and silicon is essential for Nb recovery. Acid leaching distributed metals between the solid and solution. While about 98%Nb remains in the leached mud when alkaline sintering–leaching processed. According to the investigation of comprehensive process of acid-base, tungsten residue was leached with a double excess of 15%HCl at 60°C for 90mins,and leached mud was mixed with soda as W(soda)/W(residue) =0.37，then Sintered at 850°C for 90mins，gained concentrated material with 2.74%Nb₂O₅ after leaching at 95°C for 60mins. 86.8%Nb remain in the mud. Product containing 15.8% Nb₂O₅ was gained via decomposition by HF+H₂SO₄ system and solvent extraction with MIBK. Wasted residue from alkali leaching of tin metallurgical slag were deal with the same conditions and concentrate containing 17.02% Nb₂O₅ was gained.