The present work examined the production of single-cell protein (SCP) by a newly isolated strain of Kluyveromyces marxianus EXF-5288 under increased lactose concentration of deproteinized cheese whey (DCW) and different temperatures (in °C: 20.0, 25.0, 30.0 and 35.0). To the best of the authors’ knowledge, this is the first report examining the ability of Kluyveromyces marxianus species to produce SCP at T = 20.0 °C. Different culture temperatures led to significant differences in the strain’s growth, while maximum biomass and SCP production (14.24 ± 0.70 and 6.14 ± 0.66 g/L, respectively) were observed in the cultivation of K. marxianus strain EXF-5288 in shake-flask cultures at T = 20.0 °C. Increased DCW lactose concentrations (35.0–100.0 g/L) led to increased ethanol production (Eth_max = 35.5 ± 0.2 g/L), suggesting that K. marxianus strain EXF-5288 is “Crabtree-positive”. Batch-bioreactor trials shifted the strain’s metabolism to alcoholic fermentation, favoring ethanol production. Surprisingly, K. marxianus strain EXF-5288 was able to catabolize the produced ethanol under limited carbon presence in the medium. The dominant amino acids in SCP were glutamate (15.5 mg/g), aspartic acid (12.0 mg/g) and valine (9.5 mg/g), representing a balanced nutritional profile

Wheat-flour crackers represent a staple snack option, although they lack nutritional value. Agricultural by-products such as olive and grape seeds, cereals such as barley and legumes such as lupine and chickpea are rich in bioactive compounds; therefore, flours obtained from those could represent a better option for bakery products fortification. The purpose of the present study was the investigation of total phenolic content and antioxidant activity before and after the baking of wheat crackers enriched with 10–30% olive seed, 10–30% grape seed, 10–40% lupine, 10–30% barley and 20–60% and 80% chickpea flours and the evaluation of the predicted bioavailability after in vitro digestion of crackers demonstrating the highest values. Crackers and doughs were processed and analyzed using Folin–Ciocâlteu and ferric reducing antioxidant power (FRAP) assays, respectively. Crackers with the highest properties were subjected to in vitro gastrointestinal digestion. Baking resulted in an increase in total phenolics and antioxidant activity in the majority of crackers. Olive and grape seed flour crackers demonstrated the highest antioxidant properties. Following in vitro digestion, 30% olive seed flour crackers retained the majority of polyphenols and antioxidant activity. Crackers enriched with 30% olive seed flour could represent a healthy functional bakery snack regarding their increased antioxidant properties.

The production of value-added products from microorganisms, such as single-cell protein (SCP), through the valorization of agricultural byproducts enhances circular economy while offering alternative solutions for waste treatment. In this study, SCP was obtained through the biotechnological treatment and valorization of cheese whey, the main byproduct of the dairy industry, for the development of novel edible films. To the best of the authors’ knowledge, this is the first report examining SCP as a biopolymer for edible film production. Specifically, Kluyveromyces marxianus, which has gained QPS and GRAS status, strain EXF-5288 cultivated in deproteinized cheese whey (DCW) lactose (10.0 g/L) in a 3 L fed-batch bioreactor, resulting in a SCP_max of 2.63 g/L with a protein content of up to 49.1% w/w. The addition of increased glycerol concentrations (30, 40, and 50% w/w of dry cells) as plasticizers was examined to develop SCP-based edible films. Regarding physicochemical characterization, increased glycerol concentration significantly increased moisture content (MC%) and solubility (S%), but there was not a significant difference in other parameters. Regarding wettability, SCP-based films could be described as oleophilic surfaces since the degree of oil contact angle (OCA) ranged between 46.7° ± 1.3 and 54.0° ± 0.5. The proposed holistic approach could contribute to the development of sustainable packaging materials through waste treatment.

Single cell protein (SCP) refers to dry cells of microorganisms and can be produced through bioprocesses valorizing agricultural by‐products. SCP can be used in the production of edible films which attract growing interest as an environmentally friendly replacement of synthetic packaging materials. However, consumer's perception and acceptability of such alternative packaging require investigation. In this study SCP‐based edible films were developed biotechnologically through valorization of cheese whey and consumer perception was approached holistically including focus groups of the assessment of the edible packaging made from microbes suggesting food applications, packaging information, an online survey, eye‐tracking analysis of yogurt samples with edible films and sensory analysis of biscuits in edible packaging. Texture of SCP‐based edible films scored high; however, lower scores for odor were correlated with “spoiled”/”expired” odor for SCP‐based edible films. This comprehensive study of edible packaging from microorganisms demonstrated positive consumer attitudes and preferences and it could be proposed that the use of edible packaging from microorganisms is enforceable.

The origin of a product, consumer familiarity, and purchasing identity are factors that affect the perception of cheese consumption. The present study aims at identifying consumers’ conceptualizations and attitudes towards local Greek cheeses of the North-Aegean Sea islands, such as Ladotyri, Graviera, Kasseri, Kaskavali, Melichloro, and Kalathaki, some of which have a Protected Designation of Origin (PDO) status, as opposed to cheeses of non-Greek origin, such as Cheddar, Regatto, and Gouda. Sensory and emotional attributes of local, local PDO, and imported cheeses, as well as drivers associated with consumers’ choice and acceptance above and beyond their sensory attributes, were studied using three methods: (a) flash profile to gain insight into the sensory positioning of products and description of samples; (b) qualitative analysis of focus groups to pinpoint consumer knowledge, preference, and consumption criteria; and (c) a new methodology for natural language processing and sentiment analysis of social media posts to determine consumer conceptualizations. Social media posts have proven to be a valuable source of linguistic and cultural data for cheeses. Local cheeses, including PDO products, were found to be linked to village life and family gatherings, home, tradition, and childhood memories, with saltiness and hardness being their main sensory attributes. Imported cheeses were linked to fast food, pizza, and snacking, with elasticity and gumminess as prominent sensory qualities. The main criteria for purchase were intended usage and versatility, taste and texture, price, and familiarity. The findings provide key sensory attributes, information about consumer purchasing criteria, and relevant vocabulary for the promotion of cheeses as agri-food and gastronomic identity key products.

Pulse flours are growing in popularity as alternatives to wheat in bakery products due to their high protein and nutritional value. However, the effect of different pulse species and substitution on sensory perception is unclear. The sensory perception of crackers made by partially replacing wheat with chickpea (40-80%) and lupin flour (10-30%) was evaluated using Flash profile analysis in association with instrumental analysis of texture and color. Flash profile analysis was conducted in Greece and Indonesia in order to allow culture comparison of the profiling of the samples and language by the subjects of the panel. Lightness (L) and hardness of crackers were decreased by the addition of pulses. Flash profile analysis indicated an association among color, texture, and sensory perception by judges. Derived attributes were associated with the physicochemical characteristics and raw materials of crackers for both panels. GPA analysis of Greek panel indicated that increasing the replacement of wheat led to the generation of more attributes regardless of pulse species, while the Indonesian panel was able to detect differences among pulse species.