ABSTRACT
The kinetics of carotenoid and color degradation, as well as furosine formation, were investigated in apricot fruits during convective heating at 50, 60 and 70°C. Degradation of carotenoids and color, expressed as total color difference (TCD), followed a first and zero order kinetic, respectively. The activation energy (Ea) for carotenoids degradation ranged from 73.7kJ/mol for 13-cis-ß-carotene to 120.7kJ/mol for lutein, being about 91kJ/mol for all-trans-ß-carotene. Violaxanthin and anteraxanthin were the most susceptible to thermal treatment. The furosine evolution was fitted at zero order kinetic model. The Ea for furosine formation was found to be 83.3kJ/mol and the Q10 (temperature coefficient) varied from 1.59 to 4.14 at the temperature ranges 50-60°C and 60-70°C, respectively.
Subject(s)
Carotenoids/analysis , Desiccation , Food Handling/methods , Fruit/chemistry , Lysine/analogs & derivatives , Prunus armeniaca/chemistry , Color , Hot Temperature , Kinetics , Lysine/analysis , Models, Chemical , Nutritive Value , Xanthophylls/analysisABSTRACT
In this work, 3 types of ice cream were produced: a probiotic ice cream produced by adding potentially probiotic microorganisms such as Lactobacillus casei and Lactobacillus rhamnosus; a prebiotic ice cream produced by adding inulin, a prebiotic substrate; and a synbiotic ice cream produced by adding probiotic microorganisms and inulin in combination. In addition to microbial counts, pH, acidity, and physical and functional properties of the ice creams were evaluated. The experimental ice creams preserved the probiotic bacteria and had counts of viable lactic acid bacteria after frozen storage that met the minimum required to achieve probiotic effects. Moreover, most of the ice creams showed good nutritional and sensory properties, with the best results obtained with Lb. casei and 2.5% inulin.
Subject(s)
Food Technology , Ice Cream/analysis , Ice Cream/microbiology , Prebiotics , Probiotics , Synbiotics , Animals , Colony Count, Microbial , Food Additives/pharmacology , Food Microbiology , Inulin/pharmacology , Lacticaseibacillus casei/growth & development , Lacticaseibacillus rhamnosus/growth & development , Microbial Viability , Nutritive ValueABSTRACT
In order to gain some insight into mitochondria permeability under water stress, intact coupled mitochondria were isolated from water stress adapted potato cells and investigations were made of certain transport processes including the succinate/malate and ADP/ATP exchanges, the plant mitochondrial ATP-sensitive potassium channel (PmitoKATP) and the plant uncoupling mitochondrial protein (PUMP). The Vmax values measured for succinate/malate and ADP/ATP carriers, as photometrically investigated, as well as the same values for the PmitoK(ATP) and the PUMP were found to increase; this suggested that mitochondria adaptation to water stress can cause an increase in the membrane permeability.
Subject(s)
Energy Metabolism/physiology , Intracellular Membranes/metabolism , Mitochondria/metabolism , Solanum tuberosum/metabolism , Water-Electrolyte Balance/physiology , Adenosine Diphosphate/metabolism , Adenosine Triphosphate/metabolism , Carrier Proteins/drug effects , Carrier Proteins/metabolism , Energy Metabolism/drug effects , Intracellular Membranes/drug effects , Ion Channels , Malates/metabolism , Membrane Proteins/drug effects , Membrane Proteins/metabolism , Mitochondria/drug effects , Mitochondrial ADP, ATP Translocases/drug effects , Mitochondrial ADP, ATP Translocases/metabolism , Mitochondrial Proteins , Models, Biological , Permeability , Potassium Channels/drug effects , Potassium Channels/metabolism , Solanum tuberosum/cytology , Solanum tuberosum/drug effects , Succinic Acid/metabolism , Uncoupling Protein 1 , Water-Electrolyte Balance/drug effectsABSTRACT
Linoleic acid (LA) and other fatty acids added to respiring durum wheat mitochondria (DWM) were found to cause a remarkable membrane potential (deltaPsi) decrease, as monitored by measuring safranin fluorescence. The rate of deltaPsi decrease showed (i) saturation dependence on LA concentration; (ii) fatty acid specificity; (iii) inhibition by externally added ATP, GDP, GTP and Mg(2+) and (iv) sigmoid dependence upon initial DeltaPsi, thus suggesting the existence of an active plant mitochondrial uncoupling protein (PUMP) in mitochondria from monocotyledonous species (durum wheat, Triticum durum Desf.). Surprisingly, the rate of the linoleate dependent DeltaPsi decrease was found to be activated by reactive oxygen species (ROS) (hydrogen peroxide and superoxide anion) and, moreover, linoleate proved to lower the mitochondrial generation of superoxide anion. These results suggest that ROS can activate PUMP, thus protecting the cell against mitochondrial ROS production.
Subject(s)
Carrier Proteins/metabolism , Fatty Acids/physiology , Membrane Proteins/metabolism , Mitochondria/physiology , Nucleotides/physiology , Reactive Oxygen Species/metabolism , Triticum/physiology , Intracellular Membranes/physiology , Ion Channels , Mitochondrial Proteins , Oxygen/metabolism , Uncoupling Protein 1ABSTRACT
In this study, we investigated the metabolite permeability of isolated coupled Saccharomyces cerevisiae mitochondria. The occurrence of a fumarate/malate antiporter activity was shown. The activity differs from that of the dicarboxylate carrier (which catalyses the succinate/malate antiport) in (a) kinetics (Km and Vmax values are about 27 microM and 22 nmol min(-1) mg protein(-1) and 70 microM and 4 nmol min(-1) mg protein(-1), respectively), (b) sensitivity to inhibitors, (c) Ki for the competitive inhibitor phenylsuccinate and (d) pH profiles.
Subject(s)
Antiporters/metabolism , Fumarates/metabolism , Malates/metabolism , Mitochondria/metabolism , Saccharomyces cerevisiae/metabolism , Succinates/metabolism , Adenosine Diphosphate/metabolism , Adenosine Triphosphate/metabolism , Antiporters/antagonists & inhibitors , Biological Transport, Active , Hydrogen-Ion Concentration , Kinetics , Saccharomyces cerevisiae/ultrastructureABSTRACT
Evidence is given that mitochondria isolated from Saccharomyces cerevisiae can take up externally added riboflavin and synthesise from it both flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) probably due to the existence of the mitochondrial riboflavin kinase already reported and the novel mitochondria FAD synthetase. Moreover Saccharomyces cerevisiae mitochondria can export the newly synthesised flavin derivatives to the extramitochondrial phase. This has been proven to take place with 1:1 stoichiometry with riboflavin decrease outside mitochondria, thus showing that flavin traffic occurs across the mitochondrial membranes.
