Native Non-Saccharomyces Yeasts as a Tool to Produce Distinctive and Diverse Tamjanika Grape Wines

The enological potential of two previously characterized indigenous yeast isolates, Hanseniaspora uvarum S-2 and Candida famata WB-1, in pure and sequential inoculation with commercial yeast Saccharomyces cerevisiae QA23 were analyzed in industrial-scale vinification of the grape variety Tamjanika. Their contribution to the quality and aroma profile was investigated by quantifying volatile compounds and wine sensory evaluation. Both yeast isolates were able to complete alcoholic fermentation, to reduce ethanol concentration up to 1.06% v/v (in monoculture) in comparation to S. cerevisiae QA23, and to enhance aroma and sensory profile. Based on calculated odor activity values (OAV), p-cymene, ethyl hexanoate, ethyl octanoate, and ethyl decanoate were the major aroma volatile compounds in all Tamjanika wine samples. Analyzed yeast strains significantly affected relative contribution of volatile compounds and can be considered responsible for the differences and uniqueness of the obtained wine samples. Besides confirmation of good enological and fermentative characteristics, selected isolates can be characterized as high ester-producing strains with potential to enhance the floral and fruity aromas of wine. The present study represents a further step toward the use of indigenous yeast isolates at industrial-scale fermentation in order to ensure the regional signature of Tamjanika wine

Valorization of Winery Waste: Prokupac Grape Seed as a Source of Nutritionally Valuable Oil

Valorization of winery waste is a promising solution for waste management with additional benefit of bioactive compounds isolation. The aim of this study was to analyze the nutritional and bioactive potential of oil derived from Serbian autochthonous grape seed variety Prokupac and to compare it with known international grape varieties. Additionally, two extraction methods (ultrasound assisted extraction and cold pressing) were used in order to determine their influence on physico-chemical and nutritive characteristics of grape seed oil. Different methods, including determination of physicochemical properties, content of bioactive compounds, oxidative stability and antioxidative capacity were used for the characterization of grape seed oils. Results indicated that the higher yield was obtained by ultrasound assisted extraction compared to cold pressing. The application of ultrasound assisted extraction resulted in increased α-tocopherol content and better antioxidant capacity and oxidative stability of oil. Significant differences in bioactive composition were observed for Prokupac seed oil compared to the other grape varieties. Oil extracted from Prokupac grape seed had the lowest content of polyunsaturated and the highest content of saturated fatty acids, the highest content of α-tocopherol and consequently, the best antioxidative capacity. Prokupac grape seed has a great potential for isolation of nutritive and bioactive valuable oil

Genotyping of bacterial isolates from pirotska “ironed” sausage

The Pirotska “ironed” sausage is a traditional dry fermented product from south-eastern region of Serbia, made of different types of meat (e.g. horse, goat, sheep and beef) and spices, without additives or starter cultures. The flat sausage is a totally organic, unprocessed product without heat and smoke treatment applied. The aim of this study was to characterize 120 isolates of lactic acid bacteria (LAB) from Pirotska sausage produced by six different brands in two-year period using phenotypic and genotypic identification. The phenotypic characterization and preliminary identification of LAB was based on general morphology and biochemical tests (gas production, growth at different temperatures, arginine hydrolysis etc.). The repetitive elements (REP, BOX, (GTG)5-PCR) found in the genome of these bacteria and randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) using M13 primer were used for determination of genetic polymorphism. Sequencing of 16S rRNA gene was used for species level identification. The 16S rRNA sequencing showed presence of only two species. Lactobacillus sakei was the dominant species (76%), followed by Leuconostoc mesenteroides (24%). However, plenty of genetic polymorphism within these two species was detected using (GTG)5-PCR fingerprinting. The results after comparing fingerprinting patterns of bacterial populations from different brands, due to the use of different meat types as well as different percentages of meat content, revealed some genetic similarity in few clusters and emphasized significant polymorphism within others

Vpliv surovega glicerola iz proizvodnje biodizla in vsebnosti njegovih elementov v sledovih na proizvodnjo biometana v šaržnem eksperimentu: modeliranje kot korak k enakovredni rutinski primerjavi rezultatov

In this study, crude glycerol from the biodiesel industry was tested as a co-substrate in biogas production. To investigate the influence of crude glycerol and the underlying trace element (TE) content on the efficiency of biomethane production, a batch experiment using Automatic Methane Potential Test System (AMPTS II) was carried out. The single addition of crude glycerol significantly contributed only to the total content of K (14.4%), Si (17.3%), and P (11.6%), whereas the contributions of other metals were within the range of other substrates. The addition of crude glycerol increased biomethane production, however, its utilization beyond 1% of total volume resulted in prolonged lag phase and final cessation of biomethane production. The negative effects of inorganic salts present in crude glycerol were reflected in progressively diminishing parts of glycerol and methanol being utilized in its anaerobic digestion, posing serious problems for daily routine use. A nonlinear least square regression analysis was performed to fit the Gompertz, Logistic, Transfer, and Richards models to biomethane production. The most suitable model was the Richards model, exhibiting the best fit to the experimental curves for complex substrates. Glycerol fractions remaining after biodiesel production have to be pre-tested for their negative effects on the content of TEs and inorganic salts, lag phase in biogas production, before they are used as co-substrates in biogas production phase.V študiji smo za proizvodnjo biometana kot kosubstrat uporabili surovi glicerol iz industrije proizvodnje biodizla. Da bi raziskali vpliv surovega glicerola in vsebnosti osnovnih elementov v sledovih (TE) na učinkovitost proizvodnje biometana, smo izvedli šaržni poskus z uporabo Automatic Methane Potential Test System (AMPTS II). Enkratno doziranje surovega glicerola je pomembno prispevalo le k skupni koncentraciji K (14,4 %), Si (17,3 %) in P (11,6 %), medtem ko so bili prispevki drugih elementov v sledeh v območju koncentracij drugih substratov. Z dodajanjem surovega glicerola se je povečala proizvodnja biometana, a ko je njegova uporaba presegla 1 % celotne prostornine, smo zaznali dolgotrajno lag-fazo in končno prenehanje proizvodnje biometana. Negativni učinki anorganskih soli, prisotnih v surovem glicerolu, so se odražali v postopnem zmanjševanju koncentracije glicerola in metanola, ki so se razgradili v procesu anaerobne presnove, to pa predstavlja resne težave pri vsakdanji rutinski uporabi surovega glicerola. Izvedena je bila analiza nelinearne regresije najmanjših kvadratov z uporabo modelov Gompertz, Logistic, Transfer in Richards za kumulativno proizvodnjo metana. Najprimernejši model je bil Richards, ki se je najbolj prilegal eksperimentalno izmerjenim krivuljam kompleksnih substratov. Frakcije glicerola, ki ostanejo po proizvodnji biodizla, je treba predhodno preizkusiti zaradi negativnih učinkov, ki jih lahko povzročajo TE, anorganske soli in lag-faze, preden se lahko uporabijo kot kosubstrati za pridobivanje bioplina

The characterisation of lactic acid bacteria during the fermentation of an artisan Serbian sausage (Petrovska Klobasa)

Petrovska Klobasa is an artisan Serbian sausage made only from meat and spices without any additives or starter cultures. In order to characterise lactic acid bacteria (LAB) microflora, a total number of 404 LAB strains were isolated from 15 samples collected during 90 days of the fermentation and 120 days of storage of one batch of Petrovska Klobasa. The isolates were preliminarily identified by phenotypic tests and subjected to (GTG)(5)-PCR fingerprinting. Representatives of each group were identified by 165 rDNA sequencing. The results showed that among the isolates, Lactobacillus sakei and Leuconostoc mesenteroides predominate with 36.4% and 37.1% of total LAB strains, respectively. Pediococcus pentosaceus was also isolated in high proportion (18.4%) whereas Enterococcus durans and Enterococcus caseliflavus made only 1% and 6% of the total isolates, correspondingly. The analysis of vacuum packed and modified atmosphere packed (MAP) samples showed higher presence of L mesenteroides and L sakei in the total microflora

Assessment of Chitosan Coating Enriched with Free and Nanoencapsulated Satureja montana L. Essential Oil as a Novel Tool for Beef Preservation

The effect of chitosan coating enriched with free and nanoencapsulated Satureja montana L. essential oil (EO) on microbial, antioxidant and sensory characteristics of beef was analyzed. Different concentrations of free Satureja montana L. EO (SMEO) and nanoparticles (CNPs) were added to chitosan coatings, namely 0.25%, 0.5% and 1%. The beef samples were immersed in the chitosan coatings and stored at +4 °C for 20 days. In this period, the changes in pH value, total viable count (TVC), lactic acid bacteria, psychrophilic bacteria and Pseudomonas spp. were analyzed. The lipid oxidation of beef was determined by the TBAR assay, while sensory analysis was performed by means of the descriptive evaluation method. Generally, the influence of chitosan coating with CNPs on the growth of the tested microorganisms was more pronounced compared to SMEO. Treatment with coating enriched with 1% CNPs resulted in the reduction in TVC and Pseudomonas spp. by 2.4 and 3 log CFU/g, compared to the control, respectively. Additionally, all applied coatings with SMEO and CNPs resulted in the prolonged oxidative stability of the meat The addition of free SMEO created an unnatural aroma for the evaluators, while this odor was neutralized by nanoencapsulation. The durability of color, smell and general acceptability of beef was significantly increased by application of chitosane coatings with the addition of SMEO or SMEO-CNPs, compared to the control. This research indicates the potential application of enriched chitosan coatings in beef preservation in order to improve meat safety and prolong shelf-life

Lipid Extracts Obtained by Supercritical Fluid Extraction and Their Application in Meat Products

Supercritical fluid extraction (SFE) has been recognized as the green and clean technique without any negative impact on the environment. Although this technique has shown high selectivity towards lipophilic bioactive compounds, very few case studies on the application of these extracts in final products and different food matrices were observed. Considering the recent developments in food science and the increasing application of supercritical extracts in meat products in the last decade (2012–2022), the aim of this manuscript was to provide a systematic review of the lipid extracts and bioactives successfully obtained by supercritical fluid extraction and their application in meat products as antioxidant and/or antimicrobial agents. Lipophilic bioactives from natural resources were explained in the first step, which was followed by the fundamentals of supercritical fluid extraction and application on recovery of these bioactives. Finally, the application of natural extracts and bioactives obtained by this technique as functional additives in meat and meat products were thoroughly discussed in order to review the state-of-the-art techniques and set the challenges for further studies

Lipid Extracts Obtained by Supercritical Fluid Extraction and Their Application in Meat Products

Supercritical fluid extraction (SFE) has been recognized as the green and clean technique without any negative impact on the environment. Although this technique has shown high selectivity towards lipophilic bioactive compounds, very few case studies on the application of these extracts in final products and different food matrices were observed. Considering the recent developments in food science and the increasing application of supercritical extracts in meat products in the last decade (2012–2022), the aim of this manuscript was to provide a systematic review of the lipid extracts and bioactives successfully obtained by supercritical fluid extraction and their application in meat products as antioxidant and/or antimicrobial agents. Lipophilic bioactives from natural resources were explained in the first step, which was followed by the fundamentals of supercritical fluid extraction and application on recovery of these bioactives. Finally, the application of natural extracts and bioactives obtained by this technique as functional additives in meat and meat products were thoroughly discussed in order to review the state-of-the-art techniques and set the challenges for further studies

Oenological Characterization of Native Hanseniaspora uvarum Strains

The utilization of native yeast strains associated with a distinct terroir for autochthonous grape types represents a novel trend in winemaking, contributing to the production of unique wines with regional character. Hence, this study aimed to isolate native strains of the yeast H. uvarum from the surface of various fruits and to characterize its fermentation capability in Prokupac grape must. Out of 31 yeasts, 8 isolates were identified as H. uvarum. The isolates were able to grow at low (4 °C) temperatures, SO2 concentrations up to 300 ppm and ethanol concentrations up to 5%. Additionally, they provided a good profile of organic acids during the microvinification of sterile grape must. Although the content of acetic acid (0.54–0.63 g/L) was relatively high, the sniffing test proved that the yeast isolates developed a pleasant aroma characterized as fruity. All H. uvarum isolates produced twice the concentration of glycerol compared to commercial wine yeast Saccharomyces cerevisiae, contributing to the fullness and sweetness of the wine. The results for pure and sequential fermentation protocols confirmed that the selected S-2 isolate has good oenological characteristics, the capability to reduce the ethanol content (up to 1% v/v) and a potential to give a distinctive note to Prokupac-grape wines