INFLUENCE OF ENZYMES ON THE TEXTURE OF BROWN PAN BREAD

Enzymes are commonly used to improve the textural quality of bread and to extend its shelf life. To study the effect of enzymes on the texture of brown pan bread, four types of bread were industrially manufactured using amylase, xylanase, a mixture of amylase : xylanase (1:1) and control (no enzyme). After baking, the bread samples were stored for 1, 4, 7, 10, 13, 15 and 17 days. At each storage time, bread texture was evaluated by sensory and instrumental methods, and the overall acceptability was determined. Instrumental and sensory texture data showed that the addition of amylase or amylase : xylanase decreased the staling rate of breads. Furthermore, the use of a mixture of amylase and xylanase provided better results than the addition of amylase alone. Therefore, the results suggest that the addition of a mixture of amylase and xylanase is recommended to extend the shelf life of brown pan bread. On the other hand, the addition of xylanase resulted in an increase of the staling rate. The results suggest that when xylanase is used to improve dough machinability, the addition of amylase along with it should be considered in order to prevent an increase of staling rate.     

Potentially probiotic açaí yogurt

The aim of this work was to evaluate the suitability of yogurt containing açaí pulp as a food carrier of probiotic cultures. Probiotic yogurts containing increasing amounts of açaí pulp (3, 5 and 7%) were processed and submitted to a physicochemical analysis and viable microbial count during refrigerated storage. In general, all the physicochemical parameters showed variations proportional to the amount of açaí pulp in the product formulation. Probiotic activity was verified throughout refrigerated storage for all the products, although there was a fall of one logarithmic cycle for both micro-organisms during this period (10⁷–10⁸ CFU/mL).     

Influence of Fluid Rheological Properties and Particle Location on Ultrasound-assisted Heat Transfer between Liquid and Particles

Convective heat transfer between fluids and a particle was investigated as a function of fluid rheological properties and position in the ultrasonic field, expressed as dimensionless parameters. The convective heat transfer coefficient was determined for an irregularly shaped particle immersed in sodium carboxymethylcellulose solutions of various concentrations. The extent of sonic enhancement was strongly dependent on fluid rheological properties. At low viscosity, the distance of the particle to the nearest corner of the tank was found to be significantly correlated with heat transfer coefficient; this effect decreased as viscosity increased. Dimensionless correlations were developed.     

Porcine Aminopeptidase Activity as Affected by Curing Agents

The effect of common curing agents (salt, nitrate, nitrite, ascorbic acid and glucose) on porcine muscle leucyl, arginyl, alanyl, pyroglu-tamyl and tyrosyl hydrolyzing activities was studied. Salt, ascorbate and nitrite had inhibitory effects on most enzyme activities. All activities decreased as salt increased (to 1.25 M) and/or water activity decreased (from 1.00 to 0.81). Nitrite inhibited only alanyl, pyroglu-tamyl and tyrosyl hydrolyzing activities. An in-vitro study using model conditions of three stages of dry-curing of ham, revealed that leucyl hydrolyzing activity may be important through the complete process. Other enzymes may also be involved in later stages of curing but are less important.     

DETECTION OF BIOGENIC AMINES AS MEAT SPOILAGE INDICATORS

Preparative ion exchange chromatography was performed on beef and pork samples stored at 4–6°C and wrapped in commercial film (Saran). Different peaks obtained for the two species studied, were attributable to the different type of biogenic diamines produced during spoilage. A second set of experiments was performed with pork, beef and rabbit samples. The last served as a control, since no record was available for the time elapsed since slaughtering of the animals of the other two species. Analyses were performed to determine total amine nitrogen produced during storage at chill temperatures in wrapped and unwrapped samples, and the amount of Pseudomonas , total aerobic organisms and lactic acid bacteria. Results suggested that the wrapping material did not produce the microaerophilic conditions to promote the growth of required lactic acid bacteria sufficient to outnumber the other microorganisms present. However, diamine production was slower in wrapped than in unwrapped samples.     

Allicin neuroprotective effect during oxidative/inflammatory injury involves AT1-Hsp70-iNOS counterbalance axis

The ancestral cultures have described many therapeutic properties of garlic; therefore, it is of central interest toelucidate the molecular basis explaining this millenary empirical knowledge. Indeed, it has been demonstrated aneuroprotective effect of allicin–a phytochemical present in garlic- linked to oxidative-inflammatory modulation.Allicin improved neuronal injury by heat shock protein 70 (Hsp70) and inducible nitric oxide synthase (iNOS)regulation. Also, allicin exerts renal protection involving a possible angiotensin type 1 receptor (AT1) interaction. Inconnection, AT1 overexpression has been recognized as a central deleterious factor in many brain diseases. However,there are no studies that evaluate AT1-Hsp70-iNOS interaction as a mechanism linked to neuroinflammation. Thus,our central aim is to evaluate if the allicin protective effect is associated with an AT1-Hsp70-iNOS counterbalanceaxis. For this study, a murine microglial cell line (BV-2) was injured with lipopolysaccharides and treated or not withallicin. Then, it was evaluated cell viability, proinflammatory cytokine levels, cellular oxidative stress, iNOS, Hsp70,and AT1 protein expression (cellular and mitochondrial fractions), nitrite levels, and protein-protein interactions. Theresults demonstrated that allicin could prevent neuronal injury due to a reduction in oxidative stress andinflammatory status mediated by an AT1-Hsp70-iNOS counterbalance axis linked to direct protein-protein interaction.     

Ultrastructure of the ovariole sheath in <i>Diatraea saccharalis</i> (Lepidoptera: Pyralidae)

The ultrastructure of the ovariole sheath along the Diatraea saccharalis ovariole was studied by scanning and transmission electron microscopy. Each ovariole is surrounded by an epithelial sheath, a tunica propria and scattered lumen cells. These three components of the ovariole sheath show different ultrastructural features along the ovariole, in the germarium or in the vitellarium; these differences are more evident in the epithelial sheath cells. The epithelial sheath is composed by two layers of cells, the external one running longitudinally and the internal one running circularly in the ovariole. These cells, in vitellarium, present cytoplasmic bundles of myofilaments that are arranged parallel to the long axis of the cells; these myofilaments are apparently related to the contraction movements of the follicles within the ovariole. The acellular tunica propria, composed of finely filamentous material, is attached to the adjacent follicle cells by adhesive dense plates. Between the epithelial sheath and the tunica propria there is a population of lumen cells, with morphological features of secretory activity     

PURIFICATION OF WET PROCESS PHOSPHORIC ACID BY SOLVENT EXTRACTION WITH PROPYL ETHERS.

The distribution data for the impurities (SO⁼ ₄, F^?, Fe, Al and Mg) during purification of wet phosphoric acid (WPA) with di-n-propy1 ether (DPE), di-n-propy1 ether containing 6. 5% of the isomer n-propylriso-propyl ether (DPE(M)) and di-iso-propyl ether (DIPE) at 25°C are reported. The distribution of phosphoric acid (PA)(SO⁼ ₄, F^?, Fe, Al and Mg between the conjugated phases has been investigated. The system W-WPA-DIPE shows a three-liquid-phases-at-equilibrium zone with 65.7% of phosphoric acid in the aqueous phase, 43.9% in the heavy organic phase and 4.3% in the light organic phase. The degree of purification increases, for the three solvents studied, when decreasing the PA concentration in the organic phase (except for F^?when using DPE}. Purification data for iso-arayl alcohol (1) and these three solvents are compared, showing that di-n-propyl ether with 6.5% of the isomer propyl-iso-propyl ether is the best solvent (from all solvents investigated in these series) for the purification of the wet process phosphoric acid studied.     

Al-Si-Mg(356)合金不稳态水平凝固过程中的显微组织演化（英文）

汽车和航空航天工业对减少运载工具重量的需求不断增加,这就需要发展改良的结构铝基合金。因此,本文作者研究设计Al-7%Si-0.3%Mg合金的水平凝固实验。研制并使用水冷式水平定向凝固装置。运用金相、光学显微镜、扫描电镜等传统技术表征材料的显微组织。用Thermo-Calc软件模拟含0.17%Fe(质量分数)合金的凝固路径。研究生长速度(V_L)、冷却速度(T_C)和凝固局部时间(t_(SL))等热力学参数对显微组织形成和枝晶显微组织演化的影响。当V_L和T_C值分别为0.82~0.98 mm/s和1.71~2.55°C/s时,柱状晶向等轴晶转变(CET)。通过测量一次和二次枝晶间距(分别为λ_1和λ_2)对显微组织进行表征。提出实验性定律:λ_(1,2)=f(V_L,T_C),λ_2=f(t_(SL));并观察到枝晶区包含以下共晶混合物:α(Al)+Si+π-Al_8Mg_3Fe Si_6+θ-Mg_2Si。