Utjecaj dodatka ekstrakta maslačka, saharoze i starter kulture na viskoznost, sposobnost zadržavanja vode i pH jogurta

Dandelion extract is a traditional Chinese medicine and contains significant nutritional value. The aim of this study was to research the optimum fermentation conditions for dandelion addition to plain yogurt using a single factor experiments and orthogonal experiment. The results of the present study demonstrated that the addition of dandelion extract affected the viscosity, water-holding capacity and pH of yogurt. Optimized conditions for dandelion addition to plain yogurt based on viscosity, incubation time, pH and sensory score were 10 % sucrose, 0.3 % of the starter cultures, incubation time of 6.5 hours and 3 % dandelion extract. A new kind of dandelion yogurt with high viscosity, good water-holding capacity and good taste was prepared in this study.Ekstrakt maslačka je tradicionalni kineski lijek, a također ima i značajnu nutritivnu vrijednost. Cilj ovog istraživanja bio je ispitati optimalne uvjete fermentacije za dodavanje maslačka u jogurt korištenjem pojedinih faktorskih eksperimenata i ortogonalnog eksperimenta. Rezultati ove studije pokazali su da dodavanje ekstrakta maslačaka utječe na viskoznost, sposobnost zadržavanja vode i pH jogurta. Optimalni uvjeti za dodavanje maslačka u jogurt na temelju viskoznosti, vremena inkubacije, pH i senzorskog rezultata bili su 10 % saharoze, 0,3 % starter kulture, vrijeme inkubacije od 6,5 sati i dodatak 3 % ekstrakta maslačka. U ovoj studiji pripremljena je nova vrsta jogurta s dodatkom maslačka karakteriziranog visokom viskoznošću, dobrom sposobnošću zadržavanja vode i dobrim okusom

A study of the tribological behaviour of TiO2 nano-additive water-based lubricants

A ball-on-disk tribometer was employed to evaluate the lubrication performance and mechanisms of innovative TiO2 nano-additive water-based lubricants. Two experimental methods were applied to determine the optimal mass fraction of TiO2. In the method I, lubricants were added onto the worn disk tracks at a predetermined time interval. In the method II, the disks were immersed in the lubricants continuously during the whole process of tribological tests. The results both indicate that the water-based lubricants can significantly reduce the coefficient of friction (COF). The 0.8 wt% TiO2 lubricant demonstrates excellent tribological properties including the lowest COF and the strongest wear resistance under all lubrication conditions. The lubrication mechanisms are attributed to the rolling and mending effects of the TiO2 nanoparticles

Effect of Extruding Full-Fat Soy Flakes on Trans Fat Content

To evaluate the effects of extrusion process on the trans fatty acids (TFAs) formation in soybean crude oils, three different extrusion parameters, namely, extrusion temperature (80–160°C), feed moisture (10–26%), and screw speed (100–500 rpm), were carried out. It was found that only five different types of TFAs were detected out using gas chromatography-mass spectrometry. Before the extrusion started, the initial amount of total TFAs was 3.04 g/100 g. However, after extruding under every level of any variable, the total amounts of TFAs were significantly higher than those in the control sample (P<0.05). For example, taking the effect of extrusion temperature into account, we can find that the highest amount of total of trans fatty acid (TTFA) was 1.62 times the amount of that in the control sample, whereas the lowest amount of TTFA was 1.54 times the amount of that in the control sample. Importantly, it was observed that the amounts of every type of trans fatty acid were not continuously increasing with the increase of the level of any extrusion variable. This phenomenon demonstrated that the formation and diversification were intricate during extruding process and need to be further studied

Oxidation Behaviour of Steel During hot Rolling by Using TiO2-Containing Water-Based Nanolubricant

The formation and performance of oxide scale on a low-alloy steel were investigated during hot rolling at 850 and 950 °C under various lubrication conditions, including benchmarks (dry condition and water) and water-based nanolubricants containing various concentrations of nano-TiO2 from 1.0 to 8.0 wt%. The results showed that the addition of nano-TiO2 particles in the lubricant significantly reduced the thickness of oxide scale and surface oxide roughness. The reduction reached the maximum when the concentration of TiO2 was 4.0 wt%. Detailed oxide phase characterisation and oxide component fraction determination revealed that hot rolling destroyed the conventional multi-layer oxide scale and promoted magnetite and haematite formation because of easy access of oxygen from the deformed structure. The effect of TiO2 was explained by the decrease in the rolling force, which led to a higher fraction of dense retaining wustite and therefore reduced the extent of further oxidation. Increasing temperature did not change the trend of lubrication effect but raised the rate of steel oxidation in general

Optimization of the aqueous enzymatic extraction of pine kernel oil by response surface methodology

AbstractAlcalase endo-protease enzyme was selected in this experiment to extract oil from pine kernel. The response surface analysis method was employed to optimize the parameters in the experiment. The optimum parameters are as follows: enzyme additive amount 1.97%, hydrolysis time 3.0h, hydrolysis temperature 51°C, materials to water rate 1:5, pH 8.4 and total oil extraction rate 89.12%. Factor contribution rate obtained from the F-test are as follows: x2>x1>x4>x3>x5. The fatty acid contents of pine kernel oil are as follows: palmitc acid 3.89%, oleic acid 19.44%, linoleic acid 50.09%, linolenic acid 0.58% and stearic acid 1.53%

Design of photobioreactors for mass cultivation of photosynthetic organisms

Photosynthetic microorganisms are important bioresources for producing desirable and environmentally benign products, and photobioreactors (PBRs) play important roles in these processes. Designing PBRs for photocatalysis is still challenging at present, and most reactors are designed and scaled up using semiempirical approaches. No appropriate types of PBRs are available for mass cultivation due to the reactors' high capital and operating costs and short lifespan, which are mainly due to a current lack of deep understanding of the coupling of light, hydrodynamics, mass transfer, and cell growth in efficient reactor design. This review provides a critical overview of the key parameters that influence the performance of the PBRs, including light, mixing, mass transfer, temperature, pH, and capital and operating costs. The lifespan and the costs of cleaning and temperature control are also emphasized for commercial exploitation. Four types of PBRs-tubular, plastic bag, column airlift, and flat-panel airlift reactors are recommended for large-scale operations. In addition, this paper elaborates the modeling of PBRs using the tools of computational fluid dynamics for rational design. It also analyzes the difficulties in the numerical simulation, and presents the prospect for mechanism-based models. (C) 2017 THE AUTHORS. Published by Elsevier LTD on behalf of the Chinese Academy of Engineering and Higher Education Press Limited Company

Effect of water-based nanolubricant containing nano-TiO2 on friction and wear behaviour of chrome steel at ambient and elevated temperatures

A novel experimental method was developed through a ball-on-disk tribometer to study the friction and wear behaviour of a chrome steel at temperatures of 25, 200 and 500 °C. Water-based nanolubricants containing different concentrations of nano-TiO2 from 0.4 to 8.0 wt% were used to investigate their effects on friction-reduction and anti-wear mechanisms, in comparison to the benchmarks under dry and water conditions. The results show that the water-based nanolubricants can significantly reduce coefficient of friction (COF) and improve wear resistance of the chrome steel at both ambient and elevated temperatures. In particular, the use of nanolubricant containing an optimal concentration (4.0 wt%) of nano-TiO2 leads to the lowest COF and the smallest ball wear among all the lubrication conditions. The friction-reduction and anti-wear mechanisms are ascribed to the rolling & polishing effects, semisolid film and solid layer contributed by the nano-TiO2 at temperatures of 25, 200 and 500 °C, respectively

Homogenate Extraction of Polysaccharides from Pine Nut Meal: Optimization and Comparison with Other Extraction Methods by Characterizing Their Extracts

Homogenate extraction technology was applied to extract polysaccharides from pine nut (Pinus koraiensis) meal, a food waste from its oil processing. The first objective was to study the effects of liquid-solid ratio, homogenate extraction time, and temperature on the yield of pine nut meal polysaccharides (PNMP) using single-factor and Box–Behnken design. The optimal processing conditions were liquid-solid ratio of 43.23 mL/g at 35°C for 2 min 50 sec that produced PNMP yield of 11.7%. Extraction factors interacted with each other significantly (p<0.01). The second objective was to compare the homogenate extract with those produced using other methods including ultrasonic, microwave, and hot water extraction. Polysaccharides were separated using HPLC based on molecular weight (MW) and characterized with the polysaccharide and protein contents of each fraction. The homogenate PNMP had the most of small size (<100 kDa) polysaccharides, and its glycoprotein fractions generally contained higher level of protein, as well as a high ABTS+ scavenging activity observed by HPLC-UV-ABTS+ assay. FTIR analysis was used to characterize the functional groups. Homogenate extraction is superior in producing PNMP compared with other common methods, and its PNMP extract has potential antioxidant benefit

Relationship between Secondary Structure and Surface Hydrophobicity of Soybean Protein Isolate Subjected to Heat Treatment

This study investigated relationship between secondary structure and surface hydrophobicity of soy protein isolate (SPI) subjected to a thermal treatment at 70~90°C. Heat denaturation increased the surface hydrophobicity and surface hydrophobicity decreased as aggregate formed. Heat caused an increase in the relative amount of α-helix structures and an overall decrease in the amount of β-sheet structures when compared with nontreated SPI. The relative amounts of secondary structures varied with time, temperature, and intensity of heat treatment applied. The β-sheet structure was most important for its significant role in denaturation of 7S globulin and following formed aggregates and even in denaturation of 11S globulin. The amount of β-sheet structure in SPI had an inverse correlation with the surface hydrophobicity when the temperature was kept below 90°C. Besides, β-turn structure increased as β-7S/B-11S aggregate formated

Performance Evaluation and Lubrication Mechanism of Water-Based Nanolubricants Containing Nano-TiO2 in Hot Steel Rolling

Hot rolling tests of a low-alloy steel were conducted at a rolling temperature of 850 °C under different lubrication conditions, including benchmarks (dry condition and water) and water-based nanolubricants containing different concentrations of nano-TiO2 from 1.0 to 8.0 wt%. The effects of nanolubricants on rolling force, surface roughness, thickness of oxide scale, and microstructure were systematically investigated through varying nano-TiO2 concentrations. The results show that the application of nanolubricants can decrease the rolling force, surface roughness and oxide scale thickness of rolled steels, and refine ferrite grains. In particular, the nanolubricant containing an optimal concentration (4.0 wt%) of nano-TiO2 demonstrates the best lubrication performance, owing to the synergistic effect of lubricating film, rolling, polishing, and mending generated by nano-TiO2