Browsing by Issue Date, starting with "1995"
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- Construction and use of a tubular picrate ion-selective electrode for reducing sugar determination in Port wine by flow-injection analysisPublication . Lopes, Teresa I. M. S.; Rangel, António O. S. S.; Lima, José L. F. C.; Montenegro, M. Conceição B. S. M.A picrate ion-selective electrode without inner reference solution and based on bis(triphenylphosphoranylidene)ammonium picrate dissolved in 2-nitrophenyloctyl ether was constructed and its characteristics assessed. With respect to reducing sugar determination in Port wine, a tubular electrode based on the same sensor system was developed and incorporated into a flow-injection manifold devised for this determination. The methodology involves a reaction between the reducing sugar and picric acid, the decrease in the picrate concentration being monitored with the tubular electrode. A linear dependence between peak width, at a fixed potential and the logarithm of sugar concentration in the range 25–200 g l−1 was obtained. The proposed system allows wine samples to be injected with no previous treatment and allows a sample throughput of 50 determinations per hour, a relative standard deviation less than 4%, and the results are comparable to the reference procedures.
- A responsabilidade civil do Estado: considerações breves sobre o seu estatuto constitucionalPublication . Vaz, Manuel Afonso
- Microbiological profile in Serra ewes' cheese during ripeningPublication . Macedo, A. C.; Malcata, F. X.; Hogg, T. A.The microflora of Serra cheese was monitored during a 35 d ripening period at three different periods within the ewe's lactation season. After 7 d ripening, the numbers of micro-organisms reached their maximum, and lactic acid bacteria (LAB) and coliforms were the predominant groups. Pseudomonads were not detected after 1 week of ripening. At all stages of ripening, cheeses manufactured in spring exhibited the lowest numbers of LAB and yeasts, whereas cheeses manufactured in winter showed the lowest numbers of coliforms and staphylococci. Leuconostoc lactis was the most abundant LAB found in Serra cheese whereas Enterococcus faecium and Lactococcus lactis spp. lactis exhibited the highest decrease in percentage composition. Numbers of both Leuc. mesenteroides and Lactobacillus paracasei tended to increase throughout ripening. The most abundant coliform was Hafnia alvei. Klebsiella oxytoca was found in curd but declined in number during ripening. Staphylococcal flora of curd was mainly composed of Staphylococcus xylosus, Staph. aureus and Staph. epidermidis. Staphylococcus xylosus was the major species found at the end of ripening. Pseudomonas fluorescens, was the only Pseudomonas species isolated from the curd. Although a broad spectrum of yeasts were found in Serra cheese, Sporobolomyces roseus was the most abundant yeast isolated.
- Vias de continuidade e ausência nos trabalhos missionários e tipográficos na Índia após o sínodo de Diamper (1599-1660)Publication . Matos, Manuel Cadafaz de
- Effet de la souche de levure sur les proprietes organoleptiques des vins issus de cinq cepages blancs portugaisPublication . Vasconcelos, I.; Moura, F.; Martins, M. C. P.; Herdeiro, M. T.; Pereira, O.; Castro, A.; Revel, G. deNeuf souches de levures commerciales, appartenant au genre Saccharomyces (six souches de S. cerevisiae et trois souches de S. bayanus), ont ete testees lors de la fermentation de moths issus de cinq cepages portugais: Loureiro, Trajadura, Pedernk Azal e Avesso. Pour un même cepage la levure d'implantation semble ne pas avoir d'influence sur la teneur en alcool et sur l'acidité totale des vins produits. Les variations des quantites produites en esters ethyliques d'acides gras (BRAG) et acetates d'alcools superieurs (AAS) peuvent varier d'un facteur 2.1 et 4.3 respectivement, pour un même cepages les teneurs maximales en AAS sont observêes avec les deux mêmes souches pour tour les cepages, a une exception pres. En ce qui concerne les alcools superieurs, les souches plus ou moths productrices different pour chaque cépage. Une etude statistique a permis d'etablir une correlation entre l'analyse chimique et l'analyse sensorielle. D'un point de vue organoleptique, les vins prefer-es sont riches en acides gras et en EEAG mais relativement pauvres en AAS.
- A Assunção da Virgem Maria no debate teológicoPublication . Carvalho, Maria Manuela de
- Do mistério aos ministérios da Igreja: significado teológico dos estados eclesiaisPublication . Galvão, Henrique de Noronha
- A iluminura do Missal de Lorvão: breve notaPublication . Peixeiro, Horácio Augusto
- Physical and chemical quality characteristics of strawberries after storage are reduced by a short delay to coolingPublication . Nunes, M. C. N.; Brecht, J. K.; Morais, A. M. M. B.; Sargent, S. A.Chandler’, ‘Oso Grande’ and ‘Sweet Charlie’ strawberries were forced-air precooled after delays of 0 or 6 h at 30 °C to study the effect of delaying precooling on physical and chemical quality characteristics of strawberry fruit. Fruit pulp temperatures were equilibrated to 30 °C prior to the start of each experiment to minimise water loss differences between treatments. Evaluations were made after storage for one week at 1 °C plus one day at 20 °C. Delaying the start of precooling resulted in about 50% greater water loss than in control fruit, which was evident as increases in superficial shrivelling. Tissue firmness values were also 14–22% lower in fruit from the delayed treatment. Fruits were darker (lower L* value), less bright (lower chroma) and apparently less red (lower a* value) with the cooling delay, although hue angle was also lower, which may reflect the occurrence of browning. No significant differences in pH were observed in these experiments, but titratable acidity was slightly lower with the delay to cooling. Delaying precooling also caused increased losses of ascorbic acid, soluble solids, fructose, glucose and sucrose compared to controls. In spite of differences related to harvest time and the variability among cultivars, the general responses were quite similar and illustrate the importance of rapid precooling and subsequent storage at low temperature for maintenance of acceptable appearance, texture and nutritive value of strawberries.
- Note: How do processing conditions affect the microflora of the sweet pomace of white grapes from Vinho Verde?Publication . Silva, M. L.; Malcata, F. Xavier; Hogg, T. A.The independent and combined effects of the addition of tartaric acid, the addition of pectinases, and the time of fermentation (and the material of the container) on the specific rates of death of lactic acid bacteria and yeasts were experimentally evaluated through a full (or fractional) two-way factorial design for pomace fermentation from the Alvarinho (and the Loureiro) varieties. Microbes present in the pomace prior to fermentation were identified in a preliminary fashion. Knowledge of the behavior of the microflora in grape pomace as a function of each major processing parameter during the step of anaerobic fermentation is important in attempts to eventually standardize and optimize the manufacture of these distilled beverages.