The demand for healthy foods without artificial food additives is constantly increasing. Hence, natural food preservation methods using bioprotective cultures could be an alternative to chemical preservatives. Thus, the main purpose of this work was to screen the indigenous lactobacilli isolated from fermented cow milk for their safety and antifungal activity to select the safe strain with the strongest fungicidal properties for the development of bioprotective acid whey protein concentrate (AWPC) based fermentates and their coatings intended for fresh cheese quality maintenance. Therefore, 12 lactobacilli strains were isolated and identified from raw fermented cow milk as protective cultures. The safety of the stains was determined by applying antibiotic susceptibility, haemolytic and enzymatic evaluation. Only one strain, Lacticaseibacillus paracasei A11, met all safety requirements and demonstrated a broad spectrum of antifungal activity in vitro. The strain was cultivated in AWPC for 48 h and grew well (biomass yield 8 log10 cfu mL−1). L. paracasei A11 AWPC fermentate was used as a vehicle for protective culture in the development of pectin-AWPC-based edible coating. Both the fermentate and coating were tested for their antimicrobial properties on fresh acid-curd cheese. Coating with L. paracasei A11 strain reduced yeast and mould counts by 1.0–1.5 log10 cfu mL−1 (p ≤ 0.001) during cheese storage (14 days), simultaneously preserving its flavour and prolonging the shelf life for six days.

Faba beans (Vicia faba L.) are an excellent protein source and should be more present in human diet, but due to their long cooking time, they are rarely used. So, in order to increase the accessibility of faba beans (Vicia faba L.), experiments were carried out to obtain new food products. Extrusion-cooking was chosen as the potential thermal cooking process and two different products were obtained. One was made exclusively from faba bean (Vicia faba L.) flour, while the second one was produced with a 50% addition of wheat flour to bean flour. Protein content, size, volume mass, pH and starch content for obtained products were analysed in order to characterise the products, as well as to see the differences from non-extruded faba beans (Vicia faba L.) and obtained samples. The experiments were carried out using faba beans (Vicia faba L.) obtained at Ltd. “Pure Horticultural Research Centre”. They were milled at Ltd. “Grauda spēks” and extruded with a twin screw extruder at Ltd. “Milzu”. The experiments showed that the extrusion process had decreased the protein content by 9%, but the starch content had risen by 13% with the addition of wheat flour. But, for sample, without added wheat flour differences were not significant. No significant size differences were observed in the obtained samples and pH values had no significant differences between extruded samples.

Edible coatings as carriers for protective lactic acid bacteria (LAB) can enhance hygienic quality to dairy products. Thus, the aim of this study was to improve the quality of artisanal acid-curd cheese by applying liquid acid whey protein concentrate based edible coating with entrapped indigenous antimicrobial Lactobacillus helveticus MI-LH13. The edible fresh acid-curd cheese coating was composed of 100% (w/w) liquid acid whey protein concentrate (LAWPC), apple pectin, sunflower oil, and glycerol containing 6 log10 CFU/mL of strain biomass applied on cheese by dipping. The cheese samples were examined over 21 days of storage for changes of microbiological criteria (LAB, yeast and mould, coliform, enterobacteria, and lipolytic microorganism), physicochemical (pH, lactic acid, protein, fat, moisture content, and colour), rheological, and sensory properties. The coating significantly improved appearance and slowed down discolouration of cheese by preserving moisture during prolonged storage. The immobilisation of L. helveticus cells into the coating had no negative effect on their viability throughout 14 days of storage at 4 °C and 23 °C. The application of coating with immobilised cells on cheeses significantly decreased the counts of yeast up to 1 log10 CFU/g during 14 days (p < 0.05) of storage and suppressed growth of mould for 21 days resulting in improved flavour of curd cheese at the end of storage. These findings indicate that LAWPC-pectin formulation provided an excellent matrix to support L. helveticus cell viability. Acting as protective antimicrobial barrier in fresh cheeses, this bioactive coating can reduce microbial contamination after processing enabling the producers to extend the shelf life of this perishable product.

The aim of the present research was to summarize the results of investigations carried out on the influence of different biodegradable polymer packaging materials on the shelf life and quality of several food products during storage. In Latvia, most of consumers consider that polymers as a material for food packaging are overly used, and they support the idea of introducing new eco-friendly food packaging. Biodegradable films were investigated for their ability to extend the shelf life of apple salad and minimally processed shredded carrots stored at 4 °C. It was found that they can guaranty the same as or even a longer shelf life than that provided by conventional polymer films. Bio PLA transparent films, thermoformed PLA containers, and cellulose-based films were tested for fresh produce packaging. Ceramis®-PLA-SiOx barrier coated films were tested for their influence on the quality of food products - rye bread, apple-black currant marmalade candies, and soft cheese Kleo - during storage. PLA and PHB films showed satisfactory results for packaging of perishable foods - salad with meat in mayonnaise. Ceramis®-PLA-SiOx films were used for vacuum packaging and also for mild thermal treatment (Sous vide) of soft cheese, providing its prolonged shelf life. Some BoPLA films specially envisaged for packaging of confectionery were tested for milk pomade sweet - sherbet - packaging. Its quality was evaluated mainly by moisture content and by changes in hardness during storage. The results suggest that biodegradable packaging materials can be a successful alternative to the conventional polymers for packaging of several food products, which could provide an essential contribution in reducing the environmental pollution.

Pectins are biopolymers, which exist inside the cell walls. Apples are the richest source of pectin comparing to other fruits and vegetables. Pectin has many health benefits and might be used in regenerative medicine as drug delivery systems, as dietary fiber, as edible films, to neutralize cholesterol and to lose excess weight. Five cultivars grown in Latvia, Tukums Municipality, Pūre parish in the season of the year 2019: 'Zarja Alatau', 'Antonovka', 'Antejs', 'Sinap Orlovskij' and 'Alesja' were selected for extraction. The study was carried out with the aim to investigate the extraction possibilities of pectin from apple pomace using pH decreasing untraditional acidifying agent -lemon juice. Pectin from apple pomace was extracted using the hot acid extraction method. The content of pectin and sugars (glucose, fructose, sucrose, total sugars) was determined by the colorimetric method and HPLC Shimadzu Prominence LC-20 Refractive Index Detector (RID-10A). The highest level of pectin was determined in the cultivars 'Antejs' (4.9 g per 100 g), 'Sinap Orlovskij' (4.8 g per 100 g) and the lowest in 'Antonovka' (3.9 g per 100 g). The results demonstrated that the highest concentrations of total sugars of glucose, fructose and sucrose were in the cultivars 'Antejs' (Glucose 1.2, Fructose 6.6, Sucrose 4.1 = Total sugars 11.9 g per 100 g) and 'Alesja' (Glucose 1.2, Fructose 6.6, Sucrose 3.6 = Total sugars 11.4 g per 100 g), the lowest in 'Antonovka' (Glucose 0.9, Fructose 6.0, Sucrose 1.4 = Total sugars 8.3 g per 100 g). The best content of pectin and total sugars from all cultivars was detected in the apple cultivar 'Antejs'.