Growth kinetics of probiotic lactobacilli strains cultivated in a laboratory bioreactor with stirring

Batch cultivation in a laboratory bioreactor with stirring of the lactobacilli strains with probiotic properties Lacticaseibacillus casei ssp. casei G17 and Lacticaseibacillus casei ssp. rhamnosus G16 isolated from pink blossom of Rosa damascena Mill was conducted. The changes in the concentration of viable cells were monitored. The growth kinetics was modeled applying the classic and modified logistic curve model and the maximum specific growth rate (μm) of the studied strains was determined. The classical model of the logistic curve showed higher μm for Lacticaseibacillus casei ssp. casei G17 - 0.133 h-1, compared to Lacticaseibacillus casei ssp. rhamnosus G16 - 0.120 h-1, while the modified logistic curve model predicted comparable maximum growth rates of 0.105 h-1 and 0.101 h-1 for Lacticaseibacillus casei ssp. casei G17 and Lacticaseibacillus casei ssp. rhamnosus G16, respectively. Lacticaseibacillus casei ssp. casei G17 was characterized by a shorter induction period (τa = 0.72 h) and a higher adaptation rate constant (k0 – 0.390 h-1) compared to Lacticaseibacillus casei ssp. rhamnosus G16 (τa=1.66 h; k0=0.110 h-1). The established kinetic parameters show that Lacticaseibacillus casei ssp. rhamnosus G16 needs the addition of growth factors in the fermentation medium that will help to optimize its composition for scaling up the fermentation process

Examining the possibilities for application of pea milk in obtaining fermented probiotic foods

Examining the possibilities for application of pea milk in obtaining fermented probiotic foods: Lactic Acid Bacteria are able to coagulate animal milks. Fermentation with only vegetable milk does not lead to the production of tasty and quality dairy products but mixes of animal and vegetable milks seem to be preferable for obtaining fermented product of better quality. The Lactobacillus strains Lactobacillus acidophilus Ar, Lactobacillus acidophilus 1A29 3 , Lactobacillus plantarum 226-15, Lactobacillus casei ssp. casei Shirota D, Lactobacillus plantarum BB22; the starter MZ 2 and the yeast strain Saccharomyces cerevisiae ssp. diastaticus 25-G have been selected because of their ability to grow in media containing skimmed cow's milk and pea milk (from Pisum sativum), mixed in different ratios. This leads to obtaining quality nontraditional fermented products -beverages and yoghurt. The obtained products have high concentrations of viable cells and moderate titratable acidity and they can be regarded as functional foods

Utilization of Industrial Rosa damascena Mill. By-products and Cocoa Pod Husks as Natural Preservatives in Muffins

Cocoa Pod Husks (CPH) and by-product from supercritical CO2 extracted Rosa damascena Mill. (RDCO2) were used as biopreservatives in muffins. Both by-products were rich source of polyphenols: 28.3 ± 0.6 mg/g Dry Weight (DW) and 17.9 ± 0.7 mg/g DW RDCO2 and CPH, respectively, and exhibited potent antioxidant capacity: 449.1 ± 8.5 µmol Trolox Equivalents (TE)/g DW (by ORAC method) and 58.9 ± 2.1 µmol Gallic Acid Equivalents (GAE)/g DW (by HORAC method) for the RDCO2, and 373.8 ± 9.0 µmol TE/g DW (by ORAC) and 36.8 ± 3.8 µmol GAE/g DW (by HORAC) for the CPH. RDCO2 extracts successfully inhibited development of several important pathogenic and saprophytic microorganisms causing microbial spoilage of food systems. The control muffins were good for consumption up to the 17th day, while the products supplemented with RDCO2 and CPH: until 20th day of storage at 22 ± 0.5 °C. The amount of dietary fibers in muffins supplemented with both by-products increased 3 times (8.57 ± 0.12 %) compared to control (2.91 ± 0.12 %) and the polyphenolic compounds increased 2.5 times (from 50.0 ± 0.3 for the control to 185.9 ± 0.6 mg/g DW). For the first time by-product of supercritical CO2 extraction of Rosa damascena Mill. was characterized and used as natural and cheap biopreservative

Investigation of Different Regimes of Beer Fermentation with Free and Immobilized Cells

Three different kinetic models – Monod’s model, Monod’s model with substrate inhibition, and Monod's model with substrate and product inhibition were developed for studying of beer fermentation with free and immobilized cells at different main fermentation and maturation temperatures. The most accurate model was Monod's model with substrate and product inhibition. It showed that maturation temperature had no effect on primary metabolism but it affected significantly the secondary metabolites production. In regard to carbonyl compounds and esters, the increase in maturation temperature led to different trends for free and immobilized cells. Regarding the higher alcohols, the increase in maturation temperature resulted in increase in their yield coefficients for both immobilized and free cells. A sensory evaluation of beers produced with free and immobilized cells were also carried out and the results showed similar results for two beer types

Investigation of Fermentation Regimes for the Production of Low-alcohol and Non-alcohol Beers

The combination of modified mashing method and arrested fermentation for the production of low-alcohol and non-alcohol beers was studied. Therefore, five regimes for fermentation of wort with reduced fermentable sugar content with top-fermenting yeast strain at low temperatures and pitching rates were investigated. According to the fermentation dynamic results the decrease in the fermentation temperature from 10 °C to 5 °C at pitching rate of 109 Colony Forming Units cm−3 ( CFU cm−3 ) led to significantly reduced concentrations of ethanol and secondary metabolites in beer. The temperature decrease from 10 °C to 7 °C at pitching rate of 107 CFU cm−3 resulted in a decrease in the alcohol concentration and increase in all the secondary metabolite concentrations except for the vicinal diketones concentration. Data show that yeast biomass does not grow at 5 °C and at inoculum concentration of 107 CFU cm−3, which makes fermentation impossible. Fermentation kinetics using Monod's model supplemented with product inhibition was also investigated. Up to 1.7 % of alcohol accumulates in the beer in some of the variants within 7 days. At low fermentation temperatures, yeast biomass utilizes part of the substrate to maintain its vital activity under stress fermentation conditions, which leads to a reduction in the amount of alcohol synthesized. The synthesis and reduction of the secondary metabolites was delayed compared to conventional beer fermentation. The sensory evaluation of the beers produced showed that the most appealing beer was the one produced at 10 °C and pitching rate of 109 CFU cm−3

Investigation of probiotic properties of Lactobacillus helveticus 2/20 isolated from rose blossom of Rosa damascena Mill.

A Lactobacillus strain was isolated from rose blossom of Rosa damascena Mill. and it was identified as belonging to the species Lactobacillus helveticus by the application of physiological-biochemical (API 50 CHL) and molecular-genetic methods (sequencing of the 16S rRNA gene). The presence of a number of probiotic properties of L. helveticus 2/20 was investigated. The strain exhibited high antimicrobial activity against pathogenic microorganisms that cause food toxicoinfections and intoxications. L. helveticus 2/20 survived in the simulated conditions of the gastrointestinal tract – pH = 2 and pepsin, pH = 4.5 and pancreatin and pH = 8 and pancreatin, as well as in the presence of up to 0.3% bile salts, retaining a significant concentration of viable cells. It has been shown that L. helveticus 2/20 cells begin multiplying after removing the extreme conditions. The strain allowed bioreactor cultivation and freeze-drying of the obtained concentrates, with the concentration of active cells in the lyophilic preparations exceeding 1012 cfu/g. The kinetic parameters of the batch cultivation process in a bioreactor with stirring and the maximum growth rate were determined, revealing the possibilities for scaling up of the fermentation process from laboratory to industrial conditions, as well as its management. After further research on the probiotic properties of L. helveticus 2/20, it can be included in the composition of probiotics and functional foods

Tehnike minimalne obrade za proizvodnju i čuvanje hrane prilagođene individualnim potrebama

Tailor-made foods, also known as foods with programmable properties, are specialised systems with unique composition prepared by different methods, using the known mechanisms of action of their bioactive ingredients. The development of tailor-made foods involves the evaluation of individual components, including bioactive substances derived from waste products of other productions, such as essential oils. These components are evaluated both individually and in combination within food compositions to achieve specific functionalities. This review focuses on the application of minimal processing technologies for the production and preservation of tailor-made foods. It examines a range of approaches, including traditional and emerging technologies, as well as novel ingredients such as biomolecules from various sources and microorganisms. These approaches are combined according to the principles of hurdle technology to achieve effective synergistic effects that enhance food safety and extend the shelf life of tailor-made foods, while maintaining their functional properties. §Paper was presented at the 11th Central European Congress on Food and Nutrition CEFood2022, Čatež ob Savi, Slovenia, 27-30 September 2022Hrana prilagođena individualnim potrebama, poznata i kao hrana s prilagođenim svojstvima, je posebno pripremljena hrana jedinstvenog sastava, dobivena različitim metodama koje se zasnivaju na dobro poznatim mehanizmima djelovanja biološki aktivnih sastojaka. Razvoj takve hrane obuhvaća procjenu pojedinih sastojaka, uključujući biološki aktivnih spojeva izoliranih iz otpada nastalog u proizvodnji, poput eteričnih ulja. Ti su spojevi ispitani pojedinačno i u kombinaciji sa sastojcima hrane, u svrhu razvoja određenih funkcionalnih svojstava. U fokusu ovog revijalnog prikaza je primjena tehnika minimalne obrade za proizvodnju i čuvanje hrane prilagođene jedinstvenim potrebama. Razmotreni su različiti pristupi, uključujući tradicionalne i nove tehnologije, te novi sastojci, poput biomolekula što potječu iz različitih izvora i mikroorganizama. Ti su pristupi kombinirani na principu tehnologije preprekama, za uspješno postizanje sinergijskog učinka koji poboljšava sigurnost i produljuje vrijeme skladištenja hrane, dok istovremeno zadržava njezina funkcionalna svojstva

Beneficial bread without preservatives

Besides their inherent nutritional value functional foods contain substances that have beneficial impact on the functioning of organs and systems in the human body and reduce the risk of disease. Bread and bakery goods are basic foods in the diet of contemporary people. Preservatives are added to the composition of foods in order to ensure their microbiological safety, but these substances affect directly the balance of microflora in the tract. A great problem is mold and bacterial spoilage (roping) of bread. These issues require searching for new ways to improve the microbiological quality of these foods. Moreover, the deterioration of the environment leads to a significant increase in the level of insemination of the typical raw materials used for the production of bread and bakery goods. To deal with this problem manufacturers have resorted to even more extensive use of preservatives that adversely affect human health. There is an increasing demand for foods without preservatives, but with preserved or improved organoleptic characteristics and extended shelf-life

COMPARATIVE EVALUATION OF LACTOBACILLUS PLANTARUM STRAINS THROUGH MICROBIAL GROWTH KINETICS

The study of the growth kinetics of lactobacilli with pronounced probiotic properties in their batch cultivation is essential. Various models based on the logistic curvemodel, containing parameters showing the influence of the accumulating lactic acid on the biosynthesis of the product, as well as parameters showing the sensitivity of the cells to lactic acid were used to model the growth kinetics in the present work. The rate constant of adaptation of the studied strains to the used nutrient medium and the induction period were also determined. The kinetics of lactic acid synthesis was determined according to the Weibull model.The study of the growth kinetics of lactobacilli with pronounced probiotic properties in their batch cultivation is essential. Various models based on the logistic curve model, containing parameters showing the influence of the accumulating lactic acid on the biosynthesis of the product, as well as parameters showing the sensitivity of the cells to lactic acid were used to model the growth kinetics in the present work. The rate constant of adaptation of the studied strains to the used nutrient medium and the induction period were also determined. The kinetics of lactic acid synthesis was determined according to the Weibull model

Growth kinetics of probiotic lactobacilli strains cultivated in a laboratory bioreactor with stirring

Batch cultivation in a laboratory bioreactor with stirring of the lactobacilli strains with probiotic properties Lacticaseibacillus casei ssp. casei G17 and Lacticaseibacillus casei ssp. rhamnosus G16 isolated from pink blossom of Rosa damascena Mill was conducted. The changes in the concentration of viable cells were monitored. The growth kinetics was modeled applying the classic and modified logistic curve model and the maximum specific growth rate (μm) of the studied strains was determined. The classical model of the logistic curve showed higher μm for Lacticaseibacillus casei ssp. casei G17 - 0.133 h-1, compared to Lacticaseibacillus casei ssp. rhamnosus G16 - 0.120 h-1, while the modified logistic curve model predicted comparable maximum growth rates of 0.105 h-1 and 0.101 h-1 for Lacticaseibacillus casei ssp. casei G17 and Lacticaseibacillus casei ssp. rhamnosus G16, respectively. Lacticaseibacillus casei ssp. casei G17 was characterized by a shorter induction period (τa = 0.72 h) and a higher adaptation rate constant (k0 – 0.390 h-1) compared to Lacticaseibacillus casei ssp. rhamnosus G16 (τa=1.66 h; k0=0.110 h-1). The established kinetic parameters show that Lacticaseibacillus casei ssp. rhamnosus G16 needs the addition of growth factors in the fermentation medium that will help to optimize its composition for scaling up the fermentation process