scholarly journals Factors Affecting the Softening of Pickled Pasteurised Cucumbers

2009 ◽  
Vol 27 (Special Issue 1) ◽  
pp. S314-S318
Author(s):  
M. Voldřich ◽  
I. Horsáková ◽  
M. Čeřovský ◽  
H. Čížková ◽  
H. Opatová
Keyword(s):  
Heat Treatment ◽  
Microbial Contamination ◽  
Chilling Injury ◽  
Residual Activity ◽  
Inhibitory Effect ◽  
Residual Enzyme Activity ◽  
Processing Conditions ◽  
Factors Affecting ◽  
Pectolytic Enzymes ◽  
Practical Recommendations

During the last three seasons the specific softening of pickled cucumbers was observed. The defective samples were analysed, but no microbial contamination was confirmed and no residual enzyme activity as well. The hypothesis of residual activity of microbial pectinases and cellulases as the most probable softening cause was proposed. The cellulolytic and pectolytic activities of nineteen strains of moulds and yeasts isolated from the samples of soils, cucumbers and cucumber plants rests were compared. The inactivation parameters (D and z values) of pectolytic enzymes of the most active strains were determined. The inhibitory effect of Ca<sup>2+</sup> addition was evaluated within the model experiments. The residual enzyme activities were confirmed as the main cause of the defect, together with other factors such as the characteristic composition of microbial contamination, the stress or other damage of the cucumbers during the postharvest manipulation (chilling injury, humidity stress, etc.), microbial contamination of cucumbers before processing, conditions of washing, heat treatment parameters, etc. The practical recommendations for the prevention of the defect were formulated.

Effects of Heat Treatment Conditions on Fresh Taste and on Pectinmethylesterase Activity of Chilled Mandarin and Orange Juices

2005 ◽  
Vol 11 (3) ◽  
pp. 217-222 ◽  
Author(s):  
E. Sentandreu ◽  
L. Carbonell ◽  
J. V. Carbonell ◽  
L. Izquierdo
Keyword(s):  
Heat Treatment ◽  
Enzyme Activity ◽  
Retention Time ◽  
Residual Activity ◽  
The Other ◽  
Residual Enzyme Activity ◽  
Drastic Reduction ◽  
High Quality ◽  
Treatment Conditions ◽  
Mandarin Juices

Juices from oranges, mandarins and hybrids were thermally treated in a plate exchanger at different conditions to evaluate the effects of treatment on fresh taste and on residual pectinmethylesterase (PME) activity. Freshness was significantly higher in fresh juices than in samples treated at 70°C or higher temperatures for 10 seconds of retention time, whereas no differences were found among samples heated at temperatures from 70 to 90°C for the same time, however at 95°C fresh taste decreased again. Residual PME activity was about 20% in samples treated at 70°C for 5, 10 and 20 seconds and in those heated at 80°C for 5 and 10 seconds, decreasing to 15%, also at 80°C, when retention time increased to 20 seconds. A drastic reduction to about 3% of residual activity was observed at 85°C for 10 seconds. Minimum activities of 0-1% corresponded to samples treated at 95°C. Considering the results of sensory and residual enzyme analyses, the treatment at 85°C for 10 seconds can be considered suitable. In these conditions fresh taste did not differ from that of juices treated at lower temperatures but residual enzyme activity was clearly smaller and acceptable for chilled juices, products of high quality but short shelf life. On the other hand, a deeper reduction of PME activity increasing the temperature to 95°C does not seem advisable since fresh taste decreases. Mandarin juices pasteurised at 85°C for 10 seconds and pasteurised again at the same conditions did not show a further decrease of fresh taste. Two heat treatments were usually applied when packing plants receive the juice from other factories.

scholarly journals Factors affecting the quality of apple juice

2021 ◽  
Vol 34 ◽  
pp. 06011
Author(s):  
Svetlana Popel ◽  
Pavel Epifanov ◽  
Larisa Yushan
Keyword(s):  
Heat Treatment ◽  
Waiting Time ◽  
Apple Juice ◽  
Juice Quality ◽  
Regression Equations ◽  
Factors Affecting ◽  
Technological Factors ◽  
Factors Of Production

This study reflects the research of technological factors of production that affect the quality of apple juice: temperature and time of sterilization, the influence of the type of used wort: gravity or a mixture of gravity and press fraction; the waiting time of the wort before the first heat treatment; as well as the presence of preheating. Regression equations have been developed that link the studied parameters and indicators of juice quality. The quantitative values of the characteristics of apple juice in the stated ranges, depending on the studied parameters, can be calculated by substituting the corresponding values in natural units into the developed regression equations.

Fabrication of whey proteins aggregates by controlled heat treatment and pH: Factors affecting aggregate size

2018 ◽  
Vol 112 ◽  
pp. 74-82 ◽  
Author(s):  
Mina Sobhaninia ◽  
Ali Nasirpour ◽  
Mohammad Shahedi ◽  
Abdolkhalegh Golkar ◽  
Stephane Desobry
Keyword(s):  
Heat Treatment ◽  
Whey Proteins ◽  
Aggregate Size ◽  
Factors Affecting

The mobility of intramembrane particles in non-haemolysed human erythrocytes. Factors affecting acridine-orange-induced particle aggregation

1986 ◽  
Vol 86 (1) ◽  
pp. 57-67
Author(s):  
G. Lelkes ◽  
I. Fodor ◽  
G. Lelkes ◽  
S.R. Hollan
Keyword(s):  
Acridine Orange ◽  
Intracellular Ph ◽  
Lateral Diffusion ◽  
Inhibitory Effect ◽  
Human Erythrocytes ◽  
Particle Aggregation ◽  
Experimental Conditions ◽  
Factors Affecting ◽  
Cross Links ◽  
Phosphate Buffered Saline

It has previously been shown that reversible intramembrane particle aggregation can be induced in non-haemolysed human erythrocytes. This phenomenon, which can be induced by the cationic dye Acridine Orange, has been further investigated using different experimental conditions that are expected to influence the rate of aggregation of the particles. In addition to the concentration of the dye, the rate of aggregation was also found to be dependent on the extracellular and intracellular pH, as well as on the type of buffer used. While lowering the pH of the Acridine Orange solutions resulted in decreased particle clustering, low intracellular pH increased and elevated intracellular pH decreased particle aggregation. Furthermore, at a given dye concentration and a given pH, Acridine Orange caused more intense aggregation in Tris-buffered saline than in isotonic phosphate buffer or phosphate-buffered saline. Under appropriate conditions Acridine Orange caused significant particle aggregation at concentrations as low as 0.25 mM within 30 s. During this period only discocyte-stomatocyte transformation occurred; neither agglutination nor vesiculation of the erythrocytes could be detected. Treatment of the erythrocytes with Diamide (Serva), which cross-links spectrin via disulphide bridges and thereby reduces lateral diffusion of integral membrane proteins over large distances, had no inhibitory effect on Acridine-Orange-induced particle aggregation. Heating the erythrocytes to 50 degrees C, at which temperature denaturation of spectrin and fragmentation of the erythrocytes occur, and subsequently incubating them in Acridine Orange at room temperature, caused an almost maximal rate of particle aggregation within 10–30 s, without haemolysis. The possible mechanism and significance of the particle aggregation phenomenon are discussed.

scholarly journals Genetic diversity in Italian Lactobacillus sanfranciscensis strains assessed by multilocus sequence typing and pulsed-field gel electrophoresis analyses

Microbiology ◽  
2010 ◽  
Vol 156 (7) ◽  
pp. 2035-2045 ◽  
Author(s):  
Claudia Picozzi ◽  
Gaia Bonacina ◽  
Ileana Vigentini ◽  
Roberto Foschino
Keyword(s):  
Multilocus Sequence Typing ◽  
Geographical Area ◽  
Housekeeping Genes ◽  
Processing Conditions ◽  
Clonal Population ◽  
Factors Affecting ◽  
Lactobacillus Sanfranciscensis ◽  
Mlst Scheme ◽  
Sequence Types

Lactobacillus sanfranciscensis is a lactic acid bacterium that characterizes the sourdough environment. The genetic differences of 24 strains isolated in different years from sourdoughs, mostly collected in Italy, were examined and compared by PFGE and multilocus sequence typing (MLST). The MLST scheme, based on the analysis of six housekeeping genes (gdh, gyrA, mapA, nox, pgmA and pta) was developed for this study. PFGE with the restriction enzyme ApaI proved to have higher discriminatory power, since it revealed 22 different pulsotypes, while 19 sequence types were recognized through MLST analysis. Notably, restriction profiles generated from three isolates collected from the same firm but in three consecutive years clustered in a single pulsotype and showed the same sequence type, emphasizing the fact that the main factors affecting the dominance of a strain are correlated with processing conditions and the manufacturing environment rather than the geographical area. All results indicated a limited recombination among genes and the presence of a clonal population in L. sanfranciscensis. The MLST scheme proposed in this work can be considered a useful tool for characterization of isolates and for in-depth examination of the strain diversity and evolution of this species.

Factors affecting the growth and behaviour of axenic strains ofEntamoeba invadensRodhain, 1934

Parasitology ◽  
1958 ◽  
Vol 48 (3-4) ◽  
pp. 423-432 ◽  
Author(s):  
Elspeth W. McConnachie
Keyword(s):  
Heat Treatment ◽  
Liver Tissue ◽  
Optimum Concentration ◽  
Prolonged Storage ◽  
Liver Growth ◽  
Factors Affecting ◽  
Optimum Ph ◽  
Growth Promoting ◽  
Axenic Strains ◽  
Entamoeba Invadens

1. Axenic strains ofEntamoeba invadenscan be maintained indefinitely, by serial culture, in saline containing a slice of liver. Growth in this medium is poor, the amoebae are vacuolated, and few cysts are formed.2. The optimum concentration of NaCl for amoebic growth in this medium is 0·75–1·0%, and the optimum pH is 5·7–6·1.3. The source of the liver tissue in the medium is unimportant, but, of several tissues tested, liver was the only one which supported amoebic growth in serial culture.4. Suspensions of minced liver also supported amoebic growth, but the growth-promoting activity of the liver was removed completely by centrifugation, autoclaving, and Seitz- or glass-filtration. Heat treatment at 50–60° C. and prolonged storage at 8° C. partially inactivated the liver.5. Growth in axenic saline-liver medium does not affect the ability ofE. invadensto grow and undergo mass encystation when reassociated with suitable bacteria.

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