Modeling and Optimization of Herb-Fortified Fresh Kombucha Cheese: An Artificial Neural Network Approach for Enhancing Quality Characteristics.

In this study, an Artificial Neural Network (ANN) model is used to solve the complex task of producing fresh cheese with the desired quality parameters. The study focuses on kombucha fresh cheese samples fortified with ground wild thyme, supercritical fluid extract of wild thyme, ground sage and supercritical fluid extract of sage and optimizes the parameters of chemical composition, antioxidant potential and microbiological profile. The ANN models demonstrate robust generalization capabilities and accurately predict the observed results based on the input parameters. The optimal neural network model (MLP 6-10-16) with 10 neurons provides high r2 values (0.993 for training, 0.992 for testing, and 0.992 for validation cycles). The ANN model identified the optimal sample, a supercritical fluid extract of sage, on the 20th day of storage, showcasing specific favorable process parameters. These parameters encompass dry matter, fat, ash, proteins, water activity, pH, antioxidant potential (TP, DPPH, ABTS, FRAP), and microbiological profile. These findings offer valuable insights into producing fresh cheese efficiently with the desired quality attributes. Moreover, they highlight the effectiveness of the ANN model in optimizing diverse parameters for enhanced product development in the dairy industry.

Antimicrobial potential of kombucha fresh cheese with the addition of sage (Salvia officinalis L.) and its preparations.

One of the main challenges in fresh cheese technology is its rather limited shelf life. Prolongation of the shelf life of fresh cheese has been the focus of numerous research studies and different strategies have been thus used. One of the strategies that could prolong the shelf life of fresh cheese, as well as increase its quality is the application of different starter cultures. As the antimicrobial capacity of sage (Salvia officinalis) has been proven, the possibility of reusing its by-product obtained from a tea factory could be a significant step towards the retention of environmental equilibrium and simultaneous production of food with additional functional value. Therefore, the aim of our research was to examine the antimicrobial potential of kombucha fresh cheese with the addition of ground herbal sage, sage essential oil and sage supercritical fluid extract, and compare it with fresh cheese obtained from a commercial starter culture. In order to examine the antimicrobial activity of kombucha fresh cheese produced with the addition of sage preparations, the produced samples were artificially contaminated with common foodborne contaminants: Listeria monocytogenes, Escherichia coli and Staphylococcus aureus. The obtained results revealed that the addition of sage essential oil and herbal ground sage increased the antimicrobial activity during the 30 days of storage against E. coli in kombucha fresh cheese (decrease of 2.9 and 2.5 log CFU g-1, respectively). Implementation of sage significantly increased the antimicrobial activity of the fresh cheese produced with a commercial XPL-1 starter culture against L. monocytogenes (essential oil - 0.9 log CFU g-1 and ground sage - 1.2 log CFU g-1). In the XPL-1 sample, the growth of S. aureus was inhibited by the addition of ground sage - a decrease of 1.4 log CFU g-1. Analysis of the total phenols revealed their 5-fold higher content in the kombucha fresh cheeses compared to the samples obtained by the XPL-1 starter culture. These results correlate with the higher antimicrobial activity of the kombucha fresh cheese samples compared to the XPL-1 samples. According to our results, industrial waste, obtained as a by-product in sage (Salvia officinalis) filter tea production, can be efficiently used in fresh cheese technology in order to increase the antimicrobial activity against L. monocytogenes, E. coli and S. aureus.

Antioxidative capacity of fresh kombucha cheese fortified with sage herbal dust and its preparations.

Recent studies have intensively investigated the possibility of kombucha application as non-conventional starter culture in manufacture of various fermented dairy products. Furthermore, natural extracts from medicinal and aromatic plants contain different biologically active components which often have antioxidant properties. Based on the stated above, the aim of this research was to investigate the possibility of kombucha inoculum application as a new starter culture in fresh cheese technology, as well as to investigate effects of sage (Salvia officinalis) herbal dust (by-product from filter tea factory), its essential oil and supercritical fluid extract on antioxidative activity and sensory characteristics of produced fresh kombucha cheese during 10 days of storage. In all samples, higher ABTS than DPPH radical scavenging activity was determined. Freshly prepared and 10 days stored kombucha cheeses fortified with different types of sage preparations had significantly higher FRAP values than the control sample. All analysed samples had satisfied sensory characteristics and same scores of sensory evaluation after the production. Kombucha fresh cheese with addition of different types of sage preparations can be an innovative and valuable dairy product.

Serbian Traditional Goat Cheese: Physico-Chemical, Sensory, Hygienic and Safety Characteristics.

This research project aimed to investigate the physico-chemical, sensory, hygienic and safety characteristics of raw goat milk, whey, brine and traditional goat cheese during the ripening period of 28 days. Physico-chemical parameters included the determination of dry matter, fat, ash, protein, pH, water activity and NaCl content. The presence of Enterobacteriaceae and fungi was estimated on milk and cheese samples, and a sensory panel evaluated the products' features and acceptability during ripening. The results show that the cheese under study belongs to the acid full-fat cheese group. A consumer panel attributed high scores to the goat cheese, until the 21st day of ripening. After this period, the overall features altered significantly, including augmented bitterness, odor intensification and the development of molds on the surface. The presence of fungi, associated with Enterobacteriaceae, suggests that the hygiene of the production processes needs to be improved. Regarding microbial safety, the detection of putative pathogens and antibiotic resistances recommend an active surveillance of traditional foods to avoid foodborne infections and/or the dissemination of resistant microorganisms along the food chain.

Kinetics of lactose fermentation in milk with kombucha starter.

The aim of this research was to investigate the effect of new, non-conventional starter culture on the kinetics of the lactose transformation during milk fermentation by kombucha, at pH 5.8; 5.4; 5.1; 4.8; and 4.6, at two different temperatures 37 °C and 42 °C. Milk fermentation at 42 °C lasted significantly shorter (about 5 h, 30 min) compared to the fermentation at 37 °C. Changes of lactose concentration at the both temperatures are consisting of two retaining stages and very steep decline in-between. The analysis of the rate curves showed that the reaction rate passes through the maximum after 9 h, 30 min at 37 °C and after 4 h at 42 °C. The sigmoidal saturation curve indicates a complex kinetics of lactose fermentation by kombucha starter.

Modeling of rheological characteristics of the fermented dairy products obtained by novel and traditional starter cultures.

Tree different fermented dairy products obtained by conventional and non-conventional starter cultures were investigated in this paper. Textural and rheological characteristics as well as chemical composition during 21 days of storage were analysed and subsequent data processing was performed by principal component analysis. The analysis of samples` flow behaviour was focused on their time dependent properties. Parameters of Power law model described flow behaviour of samples depended on used starter culture and days of storage. The Power law model was applied successfully to describe the flow of the fermented milk, which had characteristics of shear thinning and non-Newtonian fluid behaviour.

In silico identification of milk antihypertensive di- and tripeptides involved in angiotensin I-converting enzyme inhibitory activity.

Identification of bioactive milk peptides could improve food technology through improved selection of food supplements with a focus on antihypertensive properties. We hypothesized that angiotensin I-converting enzyme (ACE) inhibitory activities of milk di- and tripeptides could be predicted using 3-dimensional quantitative structure activity relationship methods and that these activities could be explained through evaluation of structural features (hydrogen bond donor/acceptor, hydrophobic, steric, and electrostatic) that are responsible for this bioactivity. We aimed to build comparative molecular field analysis (CoMFA) models combined with in silico digestion to predict the peptide sequences released from enzymatic digestion and to evaluate peptides without experimental data. Furthermore, molecular docking simulation was performed with the aim to evaluate structural features. Molecular docking simulations revealed that the most potent inhibitory peptides contain hydrophobic amino acids that enter deep into the hydrophobic pocket of the ACE active site and make interactions with its residues. CoMFA results point out favorable steric interactions and electronegativity at the C-terminus of the milk dipeptides. The CoMFA model appears to favor electropositive amino acids at the second place in tripeptides and electronegative interaction with Tyr520. Furthermore, predicted values of ACE inhibitory activity of dipeptides obtained by peptide cutter are relatively high, which recommend them for application as functional food supplements and natural alternatives to ACE inhibitory drugs. This research suggests that obtained 3-dimensional quantitative structure activity relationship models are able to successfully identify milk-derived di- and tripeptides that have significant antihypertensive activity and provide information for screening and design of novel ACE inhibitors that could be used as supplements in human nutrition.