组织工程用Mg-Ca-Zn-Co合金泡沫的制备及氟化处理（英文）

以尿素为造孔剂,利用基于粉末冶金法的"造孔剂-水浸出"法制备可用于骨组织工程的多孔Mg-Ca-Zn-Co合金支架。并研究合金浸泡在氟化氢(HF)溶液中进行表面氟化处理对合金耐腐蚀性能的影响。结果表明,随着Zn含量的增加,合金的弹性模量提高。Ca的添加可以阻止烧结过程中样品的氧化。合金在模拟体液中的电化学腐蚀行为的研究表明,当Zn含量从1.0%增加到3.0%时,合金的腐蚀率和质量损失都先减小,随着Zn含量的进一步增加,合金的腐蚀率和质量损失而后增大。氟化处理后合金表面形成了氟化物涂层,提高了合金的耐腐蚀性。     

The effects of lipase‐encapsulating carriers on the accelerated ripening of Kashar cheese

In this study, lipase enzymes were encapsulated in κ‐carragenan, gellan and sodium alginate using emulsion and extrusion techniques and were then added to cheese milk together with rennet. The effects of the encapsulating material and ripening period on the chemical, textural and sensory characteristics of Kashar cheese were investigated. The study demonstrated that sodium alginate, gellan and κ‐carrageenan could successfully be used as lipase carrier systems to accelerate the fat breakdown process during the ripening of Kashar cheese. Those samples treated with κ‐carrageenan capsules showed the highest rate of lipolysis and proteolysis compared to those treated with the other capsules.     

INCIDENCE AND CHARACTERIZATION OF BACILLUS CEREUS IN MEAT AND MEAT PRODUCTS CONSUMED IN TURKEY

A total of 100 retail samples of meat and meat products were examined for Bacillus cereus using mannitol egg yolk polymyxin (MYP) agar as a selective isolation medium. Only 22.4% of the samples contained detectable levels of B. cereus, with counts ranging from log₁₀ 0.69 to 4.80 cfu/g, but a large number of other organisms up to log₁₀ 9.06 cfu/g were sometimes observed on the plates and may have masked the presence of B. cereus or inhibited growth. Two samples of soudjouck contained significant levels of B. cereus, sufficient enough to create a public health hazard. Selected isolates were tested for diarrheal enterotoxin production by a reversed passive latex agglutination (RPLA) test kit. Results showed no difference in the toxin production of B. cereus between beef, ground meat, soudjouck and pastrami samples. Plasmid‐profile analysis and susceptibility to the six commonly used antimicrobial agents were done on selected B. cereus isolates. About 96.4% of the isolates contained plasmids. Plasmid sizes ranged between 2.5 and 3.5 kb. The isolates showed a high rate of resistance to oxacillin (OXA) and amoxicillin (AMC) and a low frequency of resistance to the other antimicrobial agents, with all of them being susceptible to vancomycin (VAN). Approximately 54% of the isolates showed multiple resistance. There was no apparent relationship between drug resistance and carriage of plasmids.     

The effects of different incubation temperatures on the acetaldehyde content and viable bacteria counts of bio-yogurt made from ewe's milk

Yogurt and bio-yogurt were manufactured from ewe's milk using a starter culture and a probiotic culture. Incubation was carried out at 37°C and 42°C until pH 4.6 was reached and the yogurts were stored at 4 +1°C for 14 days. Analysis after 1, 7 and 14 days showed that incubation temperature and storage time significantly influenced overall properties of the samples. During the storage, whey separation and pH decreased, but titratable acidity, lactic acid and volatile fatty acid contents increased. Viable bacterial counts in all bio-yogurts were above 10⁷ cfu g⁻¹ at the end of storage.     

Production and fluoride treatment of Mg-Ca-Zn-Co alloy foam for tissue engineering applications

Highly porous Mg-Ca-Zn-Co alloy scaffolds for tissue engineering applications were produced by powder metallurgy based space holder-water leaching method. Mg-Ca-Zn-Co alloy foam can be used as a scaffold material in tissue engineering. Carbamide was used as a space holder material. Fluoride conversion coating was synthesized on the alloy by immersion treatment in hydrofluoric acid (HF). Increasing Zn content of the alloy increased the elastic modulus. Ca addition prevented the oxidation of the specimens during sintering. Electrochemical corrosion behaviour of the specimens was examined in simulated body fluid. Corrosion rate decreased with Zn addition from 1.0% up to 3.0% (mass fraction) and then increased. Mass loss of the specimens initially decreased with Zn addition up to about 3% and then increased. Fluoride conversion coating increased the corrosion resistance of the specimens.     

Influence of different exopolysaccharide-producing strains on the physicochemical, sensory and syneresis characteristics of reduced-fat stirred yoghurt

Reduced-fat stirred yoghurts were prepared by using ropy and nonropy exopolysaccharide (EPS)-producing strains or nonexopolysaccharide-producing strains. Yoghurts were evaluated for pH, titrable acidity, acetaldehyde, whey separation, viscosity, EPS concentration, sensory and microbiological analyses. Determinations of these parameters were made at 1, 7, 14 and 21 days of storage. Reduced-fat yoghurts made with EPS⁺ strains exhibited lower syneresis and acetaldehyde contents, but higher viscosity than those made with the EPS ⁻ strain. Physico-chemical results correlated with the sensory results in that panellists scored the EPS⁺ yoghurts as having an overall better mouthfeel, but a worse flavour than EPS ⁻ yoghurt.     

Patulin Adsorption Kinetics on Activated Carbon, Activation Energy and Heat of Adsorption

The kinetics of adsorption of patulin on activated carbon were studied at different initial patulin concentrations (100–400 ppb) for the temperature range 20–80°C. Apparent adsorption rate constants (k_aapp) were changed from 1.07 × 10^?3 to 1.86 × 10^?3 g^?1 min^?1 while the temperature increased from 20 to 80°C. For equilibrium adsorption curves; the Langmuir model was attempted and model parameters (K and Q°) were obtained for different temperatures. Energy of activation and heat of adsorption were determined in a batch adsorption system (E_a= 2.02 kcal/mol and ΔH = 2.24 kcal/mol). The adsorption occurred endothermically and by physical mechanisms.