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41.
María Jesús Cejudo‐Bastante Isidro Hermosín‐Gutiérrez María Soledad Pérez‐Coello 《Journal of food science》2013,78(4):C507-C513
The effects of time (storage period) and temperature (accelerated aging) on Chardonnay white wines have been evaluated. Attention was focused on a large extent of individual volatile compounds, scarcely previously reported in that kind of wines. On the one hand, several volatile compounds (mainly esters, benzenic compounds, C13‐norisoprenoids, acids, and terpenes) showed the same behavior when temperature and time were applied separately. Therefore, the effect of 1 y of storage could be predicted by temperature application during short time, just analyzing those volatile compounds. Moreover, the formation of some volatile compounds (such as dioxanes, dioxolanes, and 1,2‐dihydro‐1,1,6‐trimethylnaphtalene (TDN)) and the disappearance of some alcohols, terpenes, and furanic compounds occurred in both conventional stored and accelerated‐aged wines. On the other hand, wines submitted to high temperature differed from 1‐y stored wines on several volatile compounds, such as β‐damascenone, C6‐alcohols, dioxolanes, γ‐butyrolactone, and TDN. Therefore, it is possible to assert that the analysis of these compounds could allow checking the possible inadequate handling by employing an excessive temperature. 相似文献
42.
Patricia Cid María Jesús Doldán María Soledad Rodríguez Benjamin Prego Encarnación de Miguel 《Microscopy research and technique》2013,76(6):588-597
The morphogenesis and cell proliferation in the retina of turbot (Psetta maxima, Pleuronectiformes: Teleostei) from embryo through metamorphosis have been examined by using proliferating cell nuclear antigen (PCNA)‐immunohistochemistry and general histological procedures. In the embryonic retina, cell proliferation and spatial cell reorganization form the anlage of the pigment epithelium and neural retina. Neurogenesis begins around hatching in the temporal retina, dorsal to the optic nerve exit, and then a wave of cell differentiation spreads to the nasal retina to yield a laminated retina by the end of the prolarval turbot stage. Germinal zones in the differentiated retina persist as a rim at the retinal margin, as well as surrounding the optic fissure in premetamorphic and metamorphic turbot larvae. In these zones, progenitor cells with different morphologies show a similar spatial arrangement, which suggests that they have a similar retinogenic potential. During metamorphosis, asymmetric proliferative activity in turbot germinal zones is associated with a marked expansion of the retinal tissue. Scattered stem cells in the laminated retina, related to the lineage of rod photoreceptors, were also observed both in large premetamorphic larvae and metamorphic turbots. The proliferative activity of these cells increases considerably during metamorphosis, when rod photoreceptors become morphologically differentiated. Microsc. Res. Tech. 76:588–597, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
43.
This note shows how the transmission system can enhance competition in price-regulated power industries, thus extending earlier findings reported in the literature for deregulated industries. In the context of a two-technology, price-regulated power industry, we show that the interconnection of two markets initially supplied by a different monopoly reduces market power and raises welfare. We also show that the capacity of the transmission line plays a key role in determining whether market equilibrium lies closer to competition or monopoly. 相似文献
44.
Mercedes Jimenez Josefa Escribano Manuela Pérez-Gilabert Soledad Chazarra Juana Cabanes Francisco García-Carmona 《Lipids》2001,36(10):1169-1174
Patatin was extracted from potato tubers (Solanum tuberosum L. cv. Spunta) and purified to homogeneity by ammonium sulfate salt fractionation and one sole chromatographic step. A spectrophotometric
mixed micellar assay for patatin lipid acyl hydrolase (LAH) activity was designed with the detergent octaethylene glycol monododecyl
ether (C12E8). Patatin LAH used p-nitrophenyl butyrate (PNP-butyrate) as substrate when solubilized in (C12E8) micelles. In the mixed micellar system, patatin LAH responds to the PNP-butyrate surface concentration expressed as mol%
(=[PNP-butyrate]·100/([detergent]-critical micellar concentration)) and not to the molarity of PNP-butyrate. The kinetic parameters
were determinined; V
max was independent of the mixed micelle concentration, as was K
m, when expressed as mol%. However, K
m was dependent on C12E8 concentration when expressed in molar concentration. C12E8/PNP-butyrate proved to be a reliable system for assaying patatin LAH activity and is superior to the commonly used Triton
X-100 and SDS methods. It permits investigation of the substrate requirements of patatin LAH activity because the concentration-independent
K
m can be determined both in mol% and as the absolute number of substrate molecules per micelle. In addition, the detergent
did not affect the enzyme activity. 相似文献
45.
Escalante A Giles-Gómez M Hernández G Córdova-Aguilar MS López-Munguía A Gosset G Bolívar F 《International journal of food microbiology》2008,124(2):126-134
In this study, the characterization of the bacterial community present during the fermentation of pulque, a traditional Mexican alcoholic beverage from maguey (Agave), was determined for the first time by a polyphasic approach in which both culture and non-culture dependent methods were utilized. The work included the isolation of lactic acid bacteria (LAB), aerobic mesophiles, and 16S rDNA clone libraries from total DNA extracted from the maguey sap (aguamiel) used as substrate, after inoculation with a sample of previously produced pulque and followed by 6-h fermentation. Microbiological diversity results were correlated with fermentation process parameters such as sucrose, glucose, fructose and fermentation product concentrations. In addition, medium rheological behavior analysis and scanning electron microscopy in aguamiel and during pulque fermentation were also performed. Our results showed that both culture and non-culture dependent approaches allowed the detection of several new and previously reported species within the alpha-, gamma-Proteobacteria and Firmicutes. Bacteria diversity in aguamiel was composed by the heterofermentative Leuconostoc citreum, L. mesenteroides, L. kimchi, the gamma-Proteobacteria Erwinia rhapontici, Enterobacter spp. and Acinetobacter radioresistens. Inoculation with previously fermented pulque incorporated to the system microbiota, homofermentative lactobacilli related to Lactobacillus acidophilus, several alpha-Proteobacteria such as Zymomonas mobilis and Acetobacter malorum, other gamma-Proteobacteria and an important amount of yeasts, creating a starting metabolic diversity composed by homofermentative and heterofermentative LAB, acetic and ethanol producing microorganisms. At the end of the fermentation process, the bacterial diversity was mainly composed by the homofermentative Lactobacillus acidophilus, the heterofermentative L. mesenteroides, Lactococcus lactis subsp. lactis and the alpha-Proteobacteria A. malorum. After a 6-h fermentation, 83.27% of total sugars detected after inoculation were consumed (228.4 mM hexose equivalents) and a carbon (C) recovery of 66.18% in fermentation products was estimated. They were produced 284.4 mM C as ethanol, 71.5 mM C as acetic acid and 19 mM C as lactic acid, demonstrating the presence of homo- and heterofermentative, acetic and alcoholic metabolisms in the final product. It was also found, after hydrolysis, that the exopolysaccharide produced during the fermentation was mainly composed by fructose residues, probably inulin or levan. 相似文献
46.
Virginia León-Ruiz Soledad Vera Amelia V. González-Porto María Paz San Andrés 《Food Analytical Methods》2013,6(2):488-496
An isocratic RP-HPLC method has been developed for the identification and quantification of water-soluble vitamins in honey. The mobile phase tested was an aqueous solution of sulphuric acid and the detection was carried out simultaneously by UV and fluorescence. The separation of vitamins C (l-ascorbic acid), B1 (thiamine), B3N (nicotinamide), B3H (nicotinic acid), B5 (d-pantothenic acid) and B6 (pyridoxine) is achieved in these conditions in 15 min. The addition to the mobile phase of methanol 2 %?v/v reduced significantly the analysis time in the separation of these vitamins up to 10 min. Moreover, in presence of a cationic surfactant hexadecyltrimethylammonium bromide (CTAB) in the mobile phase, the separation of vitamin C, B1, B3N, B3H, B2 (riboflavin) and B6 is possible in 6 min. The combination of both mobile phases, H2SO4/methanol and H2SO4/methanol/CTAB, has been applied to the analysis, in isocratic mode, of several monofloral honeys (rosemary, thyme, lavender, chestnut, echium) and a honeydew honey in a short time analysis. 相似文献
47.
Agustín Helal Roberto Kreimerman Soledad Gutiérrez Ana I. Torres 《American Institute of Chemical Engineers》2019,65(12):e16775
Actors willing to participate in biomass-based value chains need to screen through a vast number of product options to identify the most promising ones. This is challenging as (a) processes for biomass-based chemicals/materials are still in development stage, thus do not perform well in techno-economic evaluations, (b) factors as which and how many links of the value chain should be uptaken, are not fully addressed by techno-economic analysis. Inspired by the Five Forces framework for industry analysis, this work presents an algorithm-like approach for assessing the attractiveness of biomass-based products. The algorithm relies on market data to classify the different sources as posing a low, medium, or high threat to the profit of a company that is considering production of a certain chemical/material. The approach is exemplified by analyzing the attractiveness of the biomass-lactic acid-polylactic acid route in the context of defining pathways for development of a biomass-based industry in Uruguay. 相似文献
48.
Jaume Jordán Stella Heras Soledad Valero Vicente Julián 《Computational Intelligence》2015,31(3):418-441
Multiagent systems are suitable for providing a framework that allows agents to perform collaborative processes in a social context. Furthermore, argumentation is a natural way of reaching agreements between several parties. However, it is difficult to find infrastructures of argumentation offering support for agent societies and their social context. Offering support for agent societies allows representation of more realistic environments to have argumentation dialogues. We propose an infrastructure to develop and execute argumentative agents in an open multiagent system. It offers tools to develop agents with argumentation capabilities. It also offers support for agent societies and their social context. The infrastructure is publicly available. Also, it has been implemented in an application scenario where argumentative agents try to reach an agreement about the best solution to solve a problem reported to the system. 相似文献
49.
Daniel P. Schwartz Aly H. Rady Soledad Castañeda 《Journal of the American Oil Chemists' Society》1994,71(4):441-444
A fast-food fat (mostly tallow), olive oil and safflower oil were heated in air for 4 d and periodically analyzed for oxofatty
acids (OFA), monohydroxy-fatty acids (HFA) and polyhydroxy-fatty acids (PHFA). After transmethylation, the OFA were estimated
as 2,4-dinitrophenylhydrazones, and the HFA and PHFA were quantitated as pyruvic acid 2,6-dinitrophenylhydrazone esters. At
least half of the maximum concentration attained for OFA, HFA and PHFA was generated between 16–24 h of heating of each oil.
Safflower oil contained greater concentrations of HFA and PHFA than either olive oil or the fast-food fat. The fastfood fat
sample contained a greater concentration of OFA than did the other oils. The sum of the concentrations of OFA, HFA and PHFA
at the time of maximum formation in the oils was approximately 260 μmoles/g at 48–72 h for safflower, 200 μmoles/g at 48–72
h for olive and 170 μmoles/g at 72 h for the fast-food fat.
Presented at the 79th Annual AOCS Meeting, Phoenix, Arizona, May 8–12, 1988. 相似文献
50.
The location of air bubbles (i.e. inside oil drops or free in the aqueous phase) was studied by image analysis as a function of the oil and biomass concentrations in a 2 L stirred tank using a simulated fermentation medium (aqueoussalt solution, castor oil, air and fungal biomass) agitated by a Rushton turbine. The solid (fungal) phase plays an important role in defining the location of bubbles, as the percentage (in bubble volume) of bubbles trapped in oil increases threefold when biomass is added to the medium. The bubbles located inside oil drops were found to occupy 60% of the total bubble volume and to be 40% smaller than those which were non‐oil associated. This phenomenon has important implications for oxygen mass transfer in multiphase fermentations. 相似文献