RESUMEN
The degradation fo steroid glycoalkaloids (SGAs) has been studied in model solutions. The number of colony forming units (CFU) was determined using a nondirect (cultivation) method during all stages of fermentation. The changes in SGAs content were observed by HPLC on the Supelcosil LC-NH2 column. The changes in alpha-tomatine concentration added to fermented Lactobacillus MRS broth have been studied. A mathematical model of steroid glycoalkaloids degradation during lactic fermentation was proposed. The mathematical model was based on the experimental data of SGA and glucose concentration and should be used for study and prediction of SGA concentration changes of fermented samples. The ratio of SGA degradation rate by fermentation and by lactic acid hydrolysis was calculated. The experimental data evaluated by proposed mathematical model for the selected strain of Lactobacillus plantarum 976H show real feasibility for SGA degradation by lactic acid fermentation.
Asunto(s)
Alcaloides/metabolismo , Ácido Láctico/metabolismo , Lactobacillus/metabolismo , Modelos Químicos , Cromatografía Líquida de Alta Presión , Recuento de Colonia Microbiana , Medios de Cultivo , Fermentación , Glicósidos/metabolismo , Hidrólisis , Cinética , Matemática , Esteroides/metabolismo , Tomatina/metabolismoRESUMEN
A sensitive, fully automated method, yielding reproducible results, was developed for the determination of relevant biogenic amines in cheese. Histamine, tyramine, putrescine, cadaverine, tryptamine, agmatine, spermidine and spermine were separated in the ion exchanger of OSTION LG ANB column of the automatic amino acid analyser Mikrotechna 339 T. Elution was carried out at 60 degrees C using a system of two buffers. The samples were extracted and precipitated by trichloroacetic acid and purified, after removal of fat, by membrane filtration. The recovery for individual amines in cheese ranged between 86% and 108%. The detection limit was of 1-5 mg of the respective amine per 1 kg of cheese and the method was linear within the dose range of 0.1-10 micrograms (for tryptamine 0.5-10 micrograms).
Asunto(s)
Aminas Biogénicas/análisis , Queso/análisis , Aminoácidos/análisis , Tampones (Química) , Calibración , Cromatografía por Intercambio Iónico , Concentración de Iones de Hidrógeno , Indicadores y Reactivos , Estándares de Referencia , Análisis de Regresión , Reproducibilidad de los Resultados , Agua/análisisRESUMEN
This work presents results of the observations of cabbage and carrot juice fermentation after inoculation with pure cultures of lactic acid bacteria. From the point of view of nitrates, utilisation, the most suitable microorganisms found from those studied were Lactobacillus plantarum 92H, Lb. plantarum 90H and Lb. delbrueckii 37H. At the same time, other observed parameters were assessed as well for their suitability for vegetable bioconservation.
Asunto(s)
Conservación de Alimentos/métodos , Lactobacillus , Nitratos , Verduras , Brassica , Daucus carota , Fermentación , Lactobacillus/metabolismo , Nitratos/metabolismoRESUMEN
The changes in benzo(a)pyrene (BaP) content of smoked sausages were monitored during 1 h cooking. During this time, the BaP content decreased from 4·80 to 1·87 µg/kg. The maximum drop in BaP content was reached in the first 20 min of cooking. Two factors affected the course of BaP changes, viz. water-holding capacity and the fat content. After excluding these factors, there was a high correlation coefficient of 0·996 between time of cooking and BaP content, which confirmed an inverse relationship between the decrease in BaP content and time of cooking. The BaP decrease was directly proportional to the decrease of fat content during cooking, when the relatively high BaP content of 7·71 µg/kg was found in the cooked-out fat.