In recent years, there has been an increasing demand for new sources of protein, both for human and animal nutrition. In addition to alternative sources of protein, such as algae or edible insects, protein obtained from yeast and mold biomass is becoming more and more important. The main fungal protein producers are the yeasts Saccharomyces cerevisiae, Kluyveromyces marxianus, Candida utilis, Yarrowia lipolytica, and the molds Fusarium venenatum, Aspergillus oryzae, and Monascus purpureus. The production of fungal protein has many advantages, including the ability to regulate the amino acid composition, high protein content in dry matter, the possibility of production in a continuous process, independence from climatic factors, and the possibility of using waste substrates as ingredients of media. One of the disadvantages is the high content of nucleic acids, which generates the need for additional purification procedures before use in food. However, a number of enzymatic, chemical, and physical methods have been developed to reduce the content of these compounds. The paper presents the current state of knowledge about fungal producers, production and purification methods, the global market, as well as opportunities and challenges for single-cell protein (SCP) production.

Extraction is one of the most commonly used methods for obtaining and purifying chemical compounds for commercial usage. The aim of this study was to evaluate the effect of unconventional permeabilization and cell disruption methods on the yield of lipid extraction from cells of the oleaginous yeast Yarrowia lipolytica. Batch cultures in a medium with molasses and waste post-frying oil were carried out. The biomass was subjected to pulsed electric field (PEF), high-pressure processing (HPP), ultrasounds (US), and several conventional processing techniques with chemical and mechanical agents (glass beads, acetone, Triton and Tween surfactants). The effectiveness of the applied methods, either on cell permeabilization or cell disruption, was investigated by analyzing the oil and total protein extraction yield and oil leaching efficiency, as well as by using microscope images. The PEF and US treatments proved to be effective permeabilization methods as a step of sample pretreatment for extraction. These unconventional physical methods could efficiently increase intracellular lipid extraction yield in solvent applications.

Pomace, a waste product, generates a huge problem in the fruit and vegetable industry. Numerous studies prove that pomace and fibre are valuable sources of many nutrients. Due to their properties, their popularity is growing in many industries. Water vapour isotherms and kinetics were determined for selected fruit fibre and pomace. The activity and water content, colour, apparent and bulk density, and material structure were also investigated. In addition, the thermal stability of the tested fibres and pomace was examined. Fibre and pomace from chokeberries, apples and currants were used in the research. The determined kinetic curves proved that apple fibre absorbed more water vapour. The isotherms were found to have a shape characteristic of type III sorption isotherms. The Guggenheim–Anderson–de Boer model (GAB) described experimental data for sorption isotherms well (taking an RMS value of less than 10% as a good fit of the model to the sorption data). Thermogravimetric analysis showed good thermal stability, and all analysed fruit fibre and pomace showed similar behaviour in the three main stages of weight loss. The results suggest that the analysed waste materials can be used for different applications, including flour replacements for food products or filling materials in edible packaging films.

The aim of this study was to develop biodegradable pectin films enriched with anthocyanin-rich fruit juices and evaluate their functional properties. Films were prepared with bilberry and blackcurrant juices, and their color response to pH, mechanical performance, thermal stability, and water vapor permeability were analyzed. The incorporation of juices significantly affected the films’ color, with ΔE values ranging from 8.41 to 39.24 for blackcurrant and 36.60 to 59.59 for wild bilberry juice, showing clear visual differences. Increasing juice concentration from 5% to 10% enhanced color intensity and opacity, with the highest opacity (12.90 a.u./mm) observed for films containing 2% pectin and 10% bilberry juice. Mechanical testing indicated reduced tensile strength after juice addition, with the lowest elongation (11.90%) noted for films with 2% pectin and 5% blackcurrant juice. The lowest water vapor permeability (7.43·10⁻¹¹ g/m·s·Pa) was recorded for films with 2% pectin. Thermal analysis revealed greater mass loss in juice-enriched films (40–44.5%) compared to controls (37.6%), reflecting the presence of volatile compounds. pH testing confirmed the films’ indicator function, with red coloration at pH 2 and shifts toward blue-grey (bilberry) or orange-green (blackcurrant) at pH 8. These findings demonstrate that pectin films enriched with dark red fruit juices exhibit promising potential for smart food packaging applications.

Edible films and coatings are biodegradable food packaging used as alternatives to conventional plastics. Their production is based on sources of natural biopolymers such as polysaccharides (e.g. starch, chitosan), proteins (e.g. casein, gelatine), and lipids (e.g. waxes, vegetable oils). The right coating manufacturing technique is a very important factor in achieving the correct adhesion, durability, and consistency of the edible coatings used. Coatings consisting of several layers usually have a higher tensile strength than coatings consisting of a single layer. In the case of multilayer coatings, there can be significant differences in surface energy at the boundary between the layers, leading to separation. The coating manufacturing methods used may include casting, coating, extrusion, and spraying.

This study investigated the feasibility of imparting active functions to commercial polylactic acid (PLA) packaging films through a coating process and the resulting impact on pasteurized milk quality. PLA films were coated with citrus or apple pectin film-forming solutions, plasticized with glycerol, and enriched with gallic acid. The effects of this coating on the thickness, optical, barrier, structural, wetting, and antioxidant properties of the PLA films were examined. The thickness of the coated films increased from 30.0 to 61.3 µm and their visual surface roughness increased, while the addition of gallic acid significantly improved their UV-VIS light-barrier capacity and antioxidant activity against ABTS and DPPH radicals. Color analysis revealed a decrease in film lightness (the L* parameter decreased from 91.0 to 90.2 after modification with apple pectin-based coatings) and a color shift toward green (negative a* parameter) and yellow (positive b* parameter). The total color difference measured using the control PLA film (uncoated PLA) as a reference was significantly lower for coated samples based on citrus pectin (0.3–0.5) than those based on apple pectin (1.6–1.7), with no significant effect of the addition of phenolic acid. The water vapor permeability of the PLA films increased from 6.8 ∙ 10⁻¹¹ g∙m⁻¹∙s⁻¹∙Pa⁻¹ to 8.2–9.4 ∙ 10⁻¹¹ g∙m⁻¹∙s⁻¹∙Pa⁻¹ and 10.1–10.6 ∙ 10⁻¹¹ g∙m⁻¹∙s⁻¹∙Pa⁻¹ for samples coated with apple and citrus pectin without and with gallic acid, respectively. However, the oxygen permeability of PLA films significantly decreased from 30.7 ∙ 10⁻¹⁶ g∙m⁻¹∙s⁻¹∙Pa⁻¹ to 0.4–0.8 ∙ 10⁻¹⁶ g∙m⁻¹∙s⁻¹∙Pa⁻¹ for coated samples. This tendency aligned with the results of carbon dioxide permeability, which was reduced from 39.1 ∙ 10⁻¹⁶ g∙m⁻¹∙s⁻¹∙Pa⁻¹ to 0.7–0.9 ∙ 10⁻¹⁶ g∙m⁻¹∙s⁻¹∙Pa⁻¹ for coated films. Water contact angle measurement showed the hydrophilic nature of all PLA samples (contact angles less than 90°). The application of analyzed control and coated PLA packaging films slowed milk souring during storage, as evidenced by reduced quality changes and delayed curd formation. The application of PLA coated with apple pectin containing gallic acid, as well as citrus pectin with or without gallic acid, resulted in the lowest pH changes after 8 days of storage (6.6 and 6.7), demonstrating the superior efficacy of these films in maintaining milk quality.