Wyniki wyszukiwania - Biblioteka Nauki

1

Kontrola stanu sanitarno-higienicznego w zakladach przemyslu rybnego za pomoca szybkich metod oferowanych przez firme Merck

100%

Malinowska-Panczyk E.

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2001

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nr 3

41-42

2

Mozliwosci zastosowania wysokiego cisnienia w przemysle owocowo-warzywnym

63%

Malinowska-Panczyk E. , Kolodziejska I.

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2010

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tom 17

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nr 2

5-15

PL

Wysokie ciśnienie w umiarkowanej temperaturze może być wykorzystane w przemyśle owocowo-warzywnym do utrwalania produktów takich, jak: soki owocowe, dżemy czy galaretki, gdyż pozwala na zachowanie naturalnej barwy, zapachu i smaku oraz wysokiej wartości odżywczej tych produktów. Chlorofil, karotenoidy i antocyjany występujące w warzywach i owocach są w dużym stopniu stabilne podczas działania ciśnienia w umiarkowanej temperaturze. Również zawartość witamin: A, C, B1, B2, i E nie zmienia się znacząco w owocach i warzywach (oraz ich przetworach) bezpośrednio po zastosowaniu wysokiego ciśnienia. Technika wysokociśnieniowa nie nadaje się jednak do przedłużania trwałości całych owoców i warzyw, gdyż w tych warunkach ma miejsce mechaniczne uszkodzenie tkanek. Prowadzi to do przyspieszenia procesów enzymatycznych i nieenzymatycznych. W wyniku uszkodzenia owoców i warzyw dochodzi do niepożądanych zmian ich tekstury, a niekiedy również zapachu.

EN

High pressure at a moderate temperature may be used in the fruit and vegetable processing industry to preserve such products as fruit juices, jams, or jellies, because it allows for retaining the natural colour, taste, flavour, and nutritional value of those products. Chlorophyll, carotenoids, and anthocyanins present in fruits and vegetables are stable, to a high degree, when high pressure and moderate temperature are applied. No significant changes in the content of vitamins A, C, B1, B2, and E in fruits and vegetables (and in their preserves) occur immediately after the high pressure has been applied. However, the high pressure technique is not suitable for extending the shelf life of whole fruits and vegetables since the tissues of the fruits and vegetables are mechanically damaged under such circumstances. This causes the enzymatic and non-enzymatic processes to accelerate. The result of mechanical damage to fruits and vegetables are undesirable changes in their textures, and, sometimes, in their smell.

3

Zmiany w komorkach mikroorganizmow pod wplywem wysokiego cisnienia

63%

Malinowska-Panczyk E. , Kolodziejska I.

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nr 11

1285-1290

EN

The mechanisms responsible for microorganisms' death under high pressure conditions are still not clear. Pressure in the range of 5-40 MPa does not usually lead to death of cells, but causes changes in their shape, dimensions and motility. In the case of some microorganisms, mainly of moulds and yeast, elongation of the cell may cause injury in the cell wall and therefore lead to their death. Changes in the cytoplasmic membrane permeability are considered to be the main reason for pressure-induced inactivation of microorganisms. According to some authors, inactivation of key enzymes leads to the inhibition of metabolic processes and the death of microorganisms. Pressure influences ribosomes and the biosynthesis of proteins. Some bacteria may be adapted to elevated pressure by regulation of protein expression. Among the new proteins, so-called PIPs (pressure-induced proteins), are identified heat-shock proteins and cold-shock proteins.

4

Effect of high pressure on selected bacteria at subzero temperature

51%

Malinowska-Panczyk E. , Kolodziejska I. , Dunajski E.

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tom 58

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nr 4

EN

The objective of these investigations was to determine the viability of selected Gram-negative and Gram-positive bacteria exposed to high pressure and subzero temperature, in the range of 60÷193 MPa and –5 ÷ –20°C, without freezing of water. The results showed that similarly to the process conducted at the temperature above 0°C, Gram-negative bacteria and cells in the exponential growth phase are more sensitive to pressure treatment than the Gram-positive bacteria and cells being in the stationary phase of growth. Variations in resistance of microorganisms to high pressure were observed not only among the different species of bacteria but also among the strains belonging to the same species. Both pressure-sensitive and pressure-resistant strains appeared within mesophilic, psychrotrophic and thermophilic bacteria. However, the tendency to greater pressure sensitivity of Gram-negative psychrotrophic and psychrophilic strains than of the Gram-negative mesophiles was emphasized. The temperature of growth influenced the microorganisms’ sensitivity to pressure.

5

Effect of high pressure and sub-zero temperature on some gram-negative bacteria

45%

Malinowska-Panczyk E. , Kolodziejska I. , Dunajski E. , Rompa M. , Cwalina S.

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nr 3

EN

The objective of the investigations was to determine the viability of selected gram-negative bacteria exposed to high pressure and sub-zero temperature, in the range of 59 ÷ 93 MPa and -5÷ -20°C, respectively, without the freezing of water. After pressurization for 24 h, at 193 MPa and -20°C, no living cells of gram-negative bacteria T. thermophilus, P. fluorescens and E. coli of the initial population number of 108 CFU/mL were detected. After pressure treatment for a shorter time than 24 h, differences in sensitivity appeared between these bacteria. The most resistant was the tested strain of E. coli. Reduction in the population of E. coli was only about 3.5 log cycles after pressurization for 30 min at -20°C, while T. thermophilus and P. fluorescens were completely inactivated under these conditions. No living cells of E. coli were found after 7 h of pressure treatment at 193 MPa and -20°C. The viability of all tested bacteria was not reduced significantly at 59 MPa, but decreased with the pressure increase. The most sensitive was P. fluorescens - a drastic loss of viability in these bacteria occurred during the time of generation of the pressure of 110 MPa at -10°C. In this period, the reduction in viable numbers of E. coli did not exceed 1 log cycle in all studied ranges of pressure and temperature. Freezing the samples under atmospheric pressure at -5°C ÷ -20°C did not exert any influence on the viability of E. coli and T. thermophilus, while the number of viable cells of P. fluorescens decreased by 0.5 ÷ 1 log cycle.

PL

Celem badań było określenie przeżywalności wybranych bakterii gramujemnych pod ciśnieniem 5 ÷193 MPa w temperaturze -5 ÷ -20°C, bez wymrożenia wody. Działanie ciśnienia 193 MPa przez 24 h w temperaturze -20°C spowodowało całkowitą inaktywację T. thermophilus, P. fluorescens i E. coli pochodzących z populacji o liczebności 108 komórek/mL. Różnice wrażliwości pomiędzy bakteriami tych gatunków pojawiły się, gdy traktowano je ciśnieniem w czasie krótszym niż 24 h. Najbardziej odporny okazał się badany szczep E. coli. Po 30 minutach działania ciśnienia 193 MPa w -20°C zmniejszenie liczebności tych bakterii wynosiło tylko około 3.5 rzędu logarytmicznego, podczas gdy T thermophilus i P. fluorescens uległy całkowitej inaktywacji w tych warunkach (tab. 2). W przypadku E. coli, żywych komórek nie wykryto po 7 h działania ciśnienia 193 MPa w -20°C (rys. 2). Ciśnienie do 59 MPa nie wpływało znacząco na liczbę bakterii wszystkich trzech badanych gatunków. Dalsze zwiększanie ciśnienia powodowało zmniejszenie ich przeżywalności. Najbardziej wrażliwy był P. fluorescens. Drastyczna utrata przeżywalności tych bakterii następowała już przy dochodzeniu do 110 MPa i temperatury -10°C (rys. 3). W przypadku E. coli zmniejszenie liczby komórek nie przekroczyło 1 rzędu logarytmicznego podczas osiągania ciśnienia i temperatury z całego badanego zakresu. Zamrożenie prób pod ciśnieniem atmosferycznym w temperaturze -5°C ÷ -20°C nie wpływało na przeżywalność komórek E. coli i T. thermophilus. W przypadku P. fluorescens zmniejszenie liczby komórek wynosiło od 0.5 do 1 rzędu logarytmicznego w każdej z tych temperatur (tab. 4).

6

Effect of high pressure and sub-zero temperature on total antioxidant capacity and the content of vitamin C, fatty acids and secondary products of lipid oxidation in human milk

38%

Martysiak-Zurowska D. , Puta M. , Barczak N. , Dabrowska J. , Malinowska-Panczyk E. , Kielbratowska B. , Kolodziejska I.

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nr 2

EN

The objective of this study was to compare of the effects of high pressure of 193 MPa at -20°C and Low Temperature Long Time pasteurization (LTLT or holder pasteurization, 62.5°C, 30 min) on the content and composition of fatty acids (FAs), concentrations of secondary products of lipid oxidation (TBARS), the total antioxidant capacity (TAC), total vitamin C and ascorbic acid (AsA) content in human milk. It was shown that no signifi - cant changes in the content and composition of FAs and TBARS levels were noted in both pressurized and LTLT pasteurized milk samples. The results obtained indicate that the antioxidant properties in pressurized human milk were also not affected. In the case of the pasteurized samples only slight (approx. 6%) and statistically insignificant decrease was observed in the Trolox equivalent antioxidant capacity (TEAC) values. Pasteurization signifi - cantly reduced the content of total vitamin C and AsA, by 35% and 24%, respectively. A minor and statistically insignificant (approx. 6%) decrease in vitamin C levels was observed in milk treated with high pressure. However, a significant decrease (by more than 11%) occurred in these conditions in AsA concentrations. The influence of high pressure treatment on AsA levels and the lack of significant changes in TEAC values point to the relative stability of the remaining antioxidant components in human milk. Further research is needed to determine the effects of high pressure of approximately 200 MPa and sub-zero temperatures on, mainly thermolabile, components of human milk, which are degraded by LTLT pasteurization.