Effect of the composition of flour nutrient substrates on the activity of microorganisms from the bacterial concentrates

The need to develop the technology of liquid acid-forming ferments using bacterial concentrates for the production of national types of bread in discrete mode was shown. The choice of bacterial concentrates was based on the optimal pH (4.5 – 5.5) and temperature (30ºC – 40ºC) of flour nutrient substrates, which are necessary to ensure the directed cultivation of microorganisms in the technology of liquid acid-forming ferments. The choice of bacterial concentrates was based on the maximum acidity that microorganisms could provide after two days of cultivation and which should be in the range of 100 to 180 degrees of Turner. The use of Belarusian bacterial concentrates on the basis of the comparative characteristics was proposed. Flour nutrient substrates for the cultivation of microorganisms from bacterial substrates have been proposed. They contained traditional components (rye flour, rye malt) and components for stimulation of activity of microorganisms from bacterial concentrates (dairy whey in liquid form, Echinaceae purpurea herba). The choice of the ratio between the components was based on the peculiarities of the technology of production of national types of bread and the possibility of providing microorganisms from bacterial concentrates with the necessary nutrients. Microorganisms of bacterial concentrate "IM-pro 1" (a consortium of dried lactic acid bacteriums and bifidobacteriums) using the proposed flour nutrient substrates during cultivation had the best activity for a shorter period of cultivation. This made it possible to propose the use of this bacterial concentrate as a source of microorganisms in liquid acid-forming ferments for national types of bread and to ensure the preparation in one stage.

Development of Dynamic Model for Real-Time Monitoring of Ripening Changes of Kimchi during Distribution

This study describes the development of a method for predicting the ripening of Kimchi according to temperature to provide information on how the ripening of Kimchi changes during distribution. Various Kimchi quality factors were assessed according to temperature and time. The acidity (lactic acid %) was selected as a good freshness index, as it is dependent on temperature and correlates strongly with the sensory quality evaluation. Moreover, it is easy to measure and reproducible in the field. The maximum value of acidity in the stationary phase was observed to increase with the storage temperature. A predictive model was developed using the Baranyi and Roberts and Polynomial models to mathematically predict the acidity. A method using the mean kinetic temperature (MKT) was proposed. The accuracy of the model using the MKT was high. It was confirmed that there is no great variation in the maximum acidity, as MKT does not change much if the temperature changes in the stationary phase where the maximum acidity is constant. This study provides important information about the development of models to predict changes in food quality index under fluctuating temperature environments. The developed kinetic model uniquely treated the quality index at the stationary phase as a function of MKT. The predictions using the food temperature histories could help suppliers and consumers make a reasonable decision on the sales, storage, and consumption of foods. The developed model could be applied to other products such as beef for which the quality index at the stationary phase also changes with temperature histories.

Phenotypic and Molecular Characterization of Lactobacilli Isolated from breast-fed Infants faeces in Bechar region,South West of Algeria

Lactobacilli are of great importance to humans, as they are essential members of a healthy human microbiota at various niches and serve as biologically and functionally important components of a healthy human diet. For this reason, the isolation of lactobacilli strains from infant feces (less than 6 months old) was carried out in Bechar region, Algeria. In total, 62 strains were isolated, purified, and identified based on the physiological and biochemical methods. For final confirmation, API 50 CHL gallery was used. The iden ca on and phylogenetic analysis of isolated strains was performed by sequencing the 16S rRNA gene, which led us to identify four species with different percentages; Lactobacillus rhamnosus, L. fermentum, L.mucosa, L. plantarum. With regard to the characteristics of technological interest, most of the identified strains exhibited good lactic acid production. However, it was not until after 3 hours of incubation at 37 °C that isolated lactobacilli produced a maximum acidity, which reached Δ pH 0.54 in the reconstituted milk. The results were different with camel milk, in the first time, and this was observed in the acidity rate which was generally lower in this type of milk in which acidity reached Δ pH 0.47 .As regards the proteolytic power, the strains showed a high level of proteolysis. Regarding the lipolytic activity, it was observed that none of the lactobacilli tested expressed lipolytic activity in the presence of buffer and olive oil, whereas the results of the strains were different as regards the flavoring activity and the texturing activity.

Free radicals scavenging -antioxidant phytochemicals in cherry tomato (Solanum lycopersicon var. Ceresiforme (DUNAL) A. Gray)

Significant differences (p ? 0.05) were observed among the cherry tomato lines for the principal antioxidants, viz. total carotenoids, lycopene and vitamin-C. Vitamin-C content ranged from 17.62 - 46.16 mg/100 g, the total carotenoid content ranged from 3.86 - 6.66 mg/100 g and lycopene content ranged from 2.83 - 5.26 mg/100 g on fresh weight basis. The total phenolics, another important class of antioxidants, also differed significantly amongst the cherry tomato line (12.41-31.17 mg gallic acid equivalent/100 g). Significant variation (p ? 0.05) was also observed for pH and titrable acidity. The pH varied from 4.15 - 4.52 and anhydrous citric acid ranged from 0.050 up to 0.323%. The total soluble solids were 3.41 - 5.16%. The maximum vitamin-C content was recorded in VRCT-6 (46.16 mg/100 g) closely followed by VRCT-7 (45.51 mg/100 g) and VRCT-15 (44.71 mg/100 g), whereas maximum total carotenoid content were recorded in VRCT-16 (6.66 mg/100 g) followed by VRCT-7 (6.48 mg/100 g) and VRCT-1(6.36 mg/100 g), respectively. On the other hand, maximum lycopene content was estimated in VRCT-16 (5.26 mg/100 g) followed by VRCT-3 (5.23 mg/100 g) and VRCT-14 (4.73 mg/100 g). Maximum acidity and total water soluble solids were recorded in VRCT-9 (0.323%) and VRCT-7 (5.16%), respectively. DOI: http://dx.doi.org/10.3329/bjb.v43i3.21591 Bangladesh J. Bot. 43(3): 255-260, 2014 (December)

The Effects of Extracellular Acidosis on Neurons and Glia in vitro

Cerebral lactic acid, a product of ischemic anaerobic glycolysis, may directly contribute to ischemic brain damage in vivo. In this study we evaluated the effects of extracellular acid exposure on 7-day-old cultures of embryonic rat forebrain. Mixed neuronal and glial cultures were exposed to either lactic or hydrochloric acid to compare the toxicities of relatively permeable and impermeable acids. Neurons were relatively resistant to extracellular HCl acidosis, often surviving 10-min exposures to pH 3.8. In the same cultures, immunochemically defined astrocytes survived 10-min HCl exposures to a maximum acidity of pH 4.2. Similarly, axonal bundles defasciculated in HCl-titrated media below pH 4.4, although their constituent fibers often survived pH 3.8. Cell death occurred at higher pH in cultures subjected to lactic acidosis than in those exposed to HCl. Over half of forebrain neurons and glia subjected for 10 min to lactic acidification failed to survive exposure to pH 4.9. Longer 1-h lactic acid incubations resulted in cell death below pH 5.2. The potent cytotoxicity of lactic acid may be a direct result of the relatively rapid transfer of its neutral protonated form across cell membranes. This process would rapidly deplete intracellular buffer stores, resulting in unchecked cytosolic acidification. Neuronal and glial death from extracellular acidosis may therefore be a function of both the degree and the rapidity of intracellular acidification.

Studies on soil reaction: IV. The soil reaction of continuously manured plots at Rothamsted and Woburn

The Rothamsted Park Grass and Woburn Barley soils are almost all acid. Ammonium sulphate has caused a considerable increase in acidity, and sodium nitrate a slight decrease. Mineral manures have but little effect, and potassium sulphate has slightly increased trie acidity of the subsoil below the more acid plots. There is some evidence that the pH value 3·8 represents a maximum acidity in the Rothamsted soil. The change in pH value as a result of liming is less than that shown in the laboratory, owing in part to the subsoil acidity.