The Use of the Yeast Kluyveromyces Fragilis B0399 in the Production of Probiotic Yogurt

Rising interest for probiotics in the recent years was caused by the possibility of their use in prevention and cure of different types of human and animal intestinal disorders. During 20th century many research studies were concentrated on finding new types of probiotic cultures. In this work, for the production of probiotic yogurt, we used commercially available, new generation probiotic lactic yeast “Turval B0399”, produced by Italian company Turval Laboratories. Turval B0399 is the culture of yeast species Kluyveromyces marxianus fragilis B0399. This yeast is characterized by the unique ability of fermenting with the enzyme β-galactosidase and by production of lactic acid, a fundamental substance in cell metabolic reactions. This probiotic yeast, naturally resistant to antibiotics, mitigate negative effects of antibiotics - by competitive colonisation of intestine it regulates intestinal dismicrobism by preventing the growth of pathogens, such as Candida albicans, while increasing the number of residential bifidobacterias. It keeps intestinal homeostasis, improves immunity (in in vitro studies it was shown to decrease the production of proinflammatory cytokines, while in studies on patients with atopic dermatitis it decreased the IgE level). It improves the general metabolism and is very successful in prevention and treatment of different intestinal disorders (Crohn's disease and Irritable Bowel syndrome). In this work we studied the growth of the yeast Kluyveromyces fragilis B0399 and its influence on the growth of the probiotic bacteria Lactobacillus acidofilus LA5 and Bifidobacterium lactis BB12 with the final aim of achieving the maximal number of live cells during the production of probiotic yogurt (>106 cfu/g). The experimental production of the probiotic yogurt with Turval B0399 was done in the Dairy Laboratory of the Department of Animal Science, Faculty of Agriculture, University of Novi Sad, while all microbiological analyses were done in JPS Dairy Institute, Novi Beograd. During the production of probiotic yogurt we followed the activity of the yeast Kluyveromyces fragilis B0399 in different concentrations – 0.5%; 1%; and 3% and under different fermentation temperatures - 39◦C; 23,5◦C and 4◦C (in the cooled probiotic yogurt). Among all studied conditions we managed to obtain the sufficient number of live yeast cells in the final product when adding 1% of Turval product during the fermentation phase on 23,5◦C, when the number of live cells is 3.5x107cfu/g probiotic bacteria and 3.6x105 cfu/g Kluyveromyces fragilis B0399. Clinical studies have shown that in order to exhibit its probiotic functions the daily uptake of the yeast Kluyveromyces fragilis has to be ≥10 millions of live cells (certified by the Italian Ministry of Health). Sensor properties of this probiotic yogurt, odour, taste and colour, are preserved up to expiry date of 30 days. Final product is safe for use and has beneficial properties for good intestinal performance and general health of its consumers

Picosecond pulsed laser ablation of silicon single crystal

Silicon-based nanoparticles (SiNPs) attract authors’ attention due its application prospects in a mutual field, from energy storage to bio-imaging. One of the most prominent methods for synthesis of SiNPs is pulsed laser ablation in liquid media (LAL), because it is simple, and it provides the minimum of contamination of the sample produced. Employed pulsed lasers in LAL are ns- and ps-, and the usage of fs- lasers are reported recently, as well. The objects of the LAL analyses are ablated craters on the Si target surface and, predominantly, the ablated material. Here, SiNPs are synthesized by ps- laser (150 ps, 1064 nm) ablation of Si single-crystal plates in de-ionized water. The focus of the work is the impact of the additional continuous wave (CW) laser (532nm) on the properties of the ablated material, i.e. SiNPs produced. The comprehensive analyses were performed, including the SiNPs’ size distribution, agglomeration abilities, aging, chemical properties (amount of oxygen and its distribution within the particles), and photoluminescence (PL) properties of the solution produced. It is demonstrated that PL properties of obtained SiNPs solution are impacted by introducing the CW laser in the ablation process. The peculiarity lies in the fact that such impact depends on both the PL excitation wavelength and the power of the introduced CW laser, which might open the possibility of successful tailoring of SiNPs produced by LAL.SPIG 2022 : 31st Summer School and International Symposium on the Physics of Ionized Gases : Contributed papers and abstracts of invited lectures, topical invited lectures and progress reports; September 5-9,2022, Belgrad

Effect of penicillin in concentration below the sensitivity level of biological methods on yoghurt cultures and yoghurt

The study was conducted to examine the effect of penicillin (0.003 IJ ml -1 of milk) in concentration below the sensitivity level of biological methods (Delvo SP and Resasurine test) on yoghurt cultures. According to the results obtained, the stated penicillin concentration prolonged the period of final incubation in the bulk starter (3 h and 20 min) and in yoghurt (3 h and 40 min). The total count of S. thermophilus colonies in the bulk starter and yoghurt is also reduced with a loss of one (log 7.32), that is, two logarithmic numbers (log 6.53) compared with the control samples (without penicillin). The total count of L. bulgaricus colonies was higher in the control samples compared with the experimental samples. Upon the final incubation period and storage for 18 h at 5 °C, there was a drop in the titratable acidity and an increase in pH values of the control samples. Microscopic examination of the control samples showed a gradual disappearance of streptococci with a complete prevalence of lactobacilli in yoghurt. Additionally, morphological changes occurred in streptococci (long chains) and lactobacilli (long and irregular rods)

IMPACT OF CROSSING OF SVRLJIG PRAMENKA WITH EAST FRIESIAN SHEEP ON CHANGE IN MILK PROTEIN CONTENT**

**Orginal scientific paper Abstract:This research paper presents the results obtained based on a study on the impact of crossing the Svrljig pramenika and East Friesian sheep breed on the milk protein content and yield in the F1 generation of crossbreeds in the course of lactation. In all the three sheep breeds, while the difference between the first and last lactation months was of exceptionally high significance. The average protein content in the milk yielded by the East Friesian sheep and crossbreeds is very similar and amounts to 5.32 % and 5.37%, while in the Svrljig Pramenka it was 5.53%. Based on the statistical significance appraisal of the differences in mean values of protein content in each stated breeds for the whole lactation period a highly significant difference between the Svrljig Pramenka and East Friesian sheep (p<0.01) can be observed, as well as a significant difference between the Svrljig Pramenka and crossbreeds (p<0.05), and an insignifacant difference between the East Friesian breed and crossbreeds(p>0.05). The crossing of the stated breeds had an impact on the increase in the total yield of milk protein in the hallfbreeds (5948.72g), which is an increase of 1755.36g compared with that in the Svrljig Pramenka, and a decrease of only 237.36g in relation to that in the East Friesian sheep breed. Key words: ewe milk, lactation, protein content, protein yiel

APE: A Command-Line Tool and API for Automated Workflow Composition

Automated workflow composition is bound to take the work with scientific workflows to the next level. On top of today’s comprehensive eScience infrastructure, it enables the automated generation of possible workflows for a given specification. However, functionality for automated workflow composition tends to be integrated with one of the many available workflow management systems, and is thus difficult or impossible to apply in other environments. Therefore we have developed APE (the Automated Pipeline Explorer) as a command-line tool and API for automated composition of scientific workflows. APE is easily configured to a new application domain by providing it with a domain ontology and semantically annotated tools. It can then be used to synthesize purpose-specific workflows based on a specification of the available workflow inputs, desired outputs and possibly additional constraints. The workflows can further be transformed into executable implementations and/or exported into standard workflow formats. In this paper we describe APE v1.0 and discuss lessons learned from applications in bioinformatics and geosciences

Continuous wave laser for tailoring the photoluminescence of silicon nanoparticles produced by laser ablation in liquid

Silicon nanoparticles (SiNPs) are attracting attention for applications in various fields, from energy storage to bio-imaging. One of their main advantages is good photoluminescence (PL) properties combined with the relatively high bio-compatibility. Here, we fabricated SiNPs by the laser ablation of silicon single crystal in de-ionized water, employing simultaneously the picosecond pulse laser (150 ps, 1064 nm, 7 mJ/pulse) and a continuous wave (CW) laser (532 nm, 270 mW). TEM analysis (bright field TEM, HRTEM, HAADF, EDS) clearly shows that the introduction of the CW laser significantly increases the crystallinity of the produced nanoparticles, which may be crucial for many optical and electronic applications. The obtained SiNPs exhibit good blue photoluminescence properties, and the introduction of the CW laser into the fabrication process leads to the considerable increases in the photoluminescence. Additionally, we conducted a detailed analysis on the aging-time dependence and the excitation wavelength-dependent PL. The results indicate that the blue photoluminescence may be ascribed to quantum confinement effect, interface related states, and defect in the O-containing layer (shell) of the nanoparticles. We demonstrate that the relative share of these mechanisms in overall PL is significantly affected by the introduction of the CW laser to the pulse laser ablation and it may improve the applicability of the Si nanoparticles produced to a wide variety of fields. Published by AIP Publishing

Nondestructive optical method for plant overall health evaluation

In vivo measurements of the optical properties of plant leaves, by spectrophotometric methods, could potentially provide very useful information for the assessment of the plant’s health. This paper describes a novel experimental set-up that enables continuous measurements of the optical reflection and transmission coefficients of broad-leaved plants. The optical spectral characteristics of leaves, in the broad wavelength range, are often a discussed topic in the scientific literature. Nevertheless, to the best of our knowledge, the real-time spectral analyses of the leaf haven’t been reported so far. Monitoring the evolution of the plant activity in real-time has resulted in the graph of the spectral Circadian rhythm as a function of time. The set-up was tested on Phaseolus vulgaris and the results of the measurements are presented and discussed

LED-based Vis-NIR spectrally tunable light source - the optimization algorithm

Background: A novel numerical method for calculating the contributions of individual diodes in a set of light emitting diodes (LEDs), aimed at simulating a blackbody radiation source, is examined. The intended purpose of the light source is to enable calibration of various types of optical sensors, particularly optical radiation pyrometers in the spectral range from 700 nm to 1070 nm. Results: This numerical method is used to determine and optimize the intensity coefficients of individual LEDs that contribute to the overall spectral distribution. The method was proven for known spectral distributions: “flat” spectrum, International Commission on Illumination (CIE) standard daylight illuminant D65 spectrum, Hydrargyrum Medium-arc Iodide (HMI) High Intensity Discharge (HID) lamp, and finally blackbody radiation spectra at various temperatures. Conclusions: The method enables achieving a broad range of continuous spectral distributions and compares favorably with other methods proposed in the literature