Edible films were developed using whey protein concentrate (WPC) and a natural bio-polymer, namely bacterial cellulose (BC). BC was produced via fermentation from orange peels and subsequently acid-hydrolyzed to obtain BC nanowhiskers (BCNW) with high crystallinity (XRD analysis). Morphology of BCNW was analyzed by SEM, TEM, and AFM. WPC/BCNW film composites, containing different amounts of BCNW (0.5–15%, w/w) were developed and characterized. WPC/BCNW film composite was analyzed by Raman spectroscopy, indicating the successful incorporation and the homogenous distribution of BCNW into the WPC film matrix. Mechanical characterization showed that BCNW behaved as a reinforcing filler in the WPC film, increasing tensile strength and Young’s modulus by 32% and 80%, respectively. In addition, water vapor permeability was reduced by 33.9% upon the addition of 0.5% BCNW. This study presented a sustainable approach towards the production of WPC films with improved tensile and water barrier properties, suggesting its potential application as a packaging material.

This study presents a food waste valorization scheme targeting to the production of novel whey protein edible films. Initially, the effect of pH of whey protein on the physical properties of films was studied. Whey protein edible films were subsequently supplemented by an antioxidant-rich extract derived from spent coffee grounds targeting to improve the functional properties of films. The results showed significant changes at different pH, indicating that, depending on the intended application, films' properties can be controlled by shifting pH of whey protein solution. Inclusion of antioxidants resulted in edible films with UV-light resistance properties, whereas the mechanical properties and in particular tensile strength and elastic (Young's) modulus were increased. Water vapor permeability of films was considerably increased by the inclusion of antioxidants, compared to control films. Additionally, whey films enriched with phenolic compounds from spent coffee grounds presented high antioxidant activity (73.2%), which was decreased only 16.8% after a 12-month storage period. The proposed valorization scheme resulted in the development of edible films with tailor-made properties conforming with the pillars of Circular Economy.

The bioeconomy concept was initially focused on resource substitution, aiming to mitigate the depletion of fossil resources and confer an alternative approach for resource utilization. Within this context, the production of biomass from diversified resources, along with its subsequent conversion, fractionation, and processing, was deemed of paramount importance. Thus, biotechnological and chemical routes along with process engineering were implemented for the production and marketing of food, feed, fuel, and fiber.

Microbial surfactants have induced research and industrial interest recently, owing to their significant advantages over the chemically produced counterparts. The pursuit of novel biosurfactant producers includes first the isolation and screening, followed by studies on fermentation strategies. The utilization of non-pathogenic strains, like lactobacilli, will expand the potential for targeted and innovative food-oriented applications. Hence, this study undertakes the evaluation of different bioprocessing parameters and schemes for biosurfactant production using Lactobacillus strains selected from a previous screening study. Cheese whey permeate (CWP) was used as a low-cost nutrient supplement, in the context of valorizing food industry by-products towards the development of biorefinery concepts. Microplates and shake flasks experiments were performed to assess the effect of pH, temperature and CWP supplementation with micronutrients and exogenous nitrogen sources. Two different media were applied in bioreactor studies, along with several fermentation conditions and significant biosurfactant production was evidenced via surface tension reduction (< 30 mN/m). Among the Lactobacillus strains studied, Limosilactobacillus fermentum ACA-DC 0183 demonstrated the maximum surface tension reduction (34.9 mN/m) after 32 h, observed even at the early hours of fermentation (4 h). Notably, the majority of the experiments indicated an inverse correlation between biosurfactants and lactic acid production. The produced biosurfactants were also extracted and partially characterized. The results presented hereof communicate promising findings in the context of mitigating the costs associated with biosurfactant production and foster the development of food industry by-products refining to enhance the circularity and sustainability of food systems.

Edible oleogels are oils structured with non-triglyceride networks, that can be used as alternative solid-like fats. The formation of olive oil oleogels structured with monoglycerides (10%, 15% and 20% MGs) and 15% MGs in combination with 5% phytosterols (PS) was investigated. Effects of storage time (0–14 d) and temperature (−20 °C, 5 °C and 25 °C) on physicochemical properties of oleogels were probed by polarized light microscopy, large deformation mechanical measurements (hardness, gel strength), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The inclusion of 5% PS into a MG-olive oil based (15%) matrix enhanced the hardness and gel strength of the PS-MG composite oleogels, due to the fact that the PS prevented a high-level organization of MGs, as evidenced by reduced melting enthalpy values, compared to oleogels formulated solely with MGs. The 15% MGs - 5% PS oleogels stored at −20 °C exhibited the strongest mechanical properties throughout storage. A gradual transformation of the crystalline morphology (sub-α to β-crystals) was also observed over time, as probed by microscopy and FTIR analysis. The rate of these changes was faster at higher storage temperatures due to enhanced mobility of the MG molecules.

The present study focuses on the production of pomegranate alcoholic beverage (PAB) from juice of the Wonderful variety. The effect of fermentation temperature (15 and 25 °C) and type of sugar added (adjustment to 20 °Brix) on the physicochemical characteristics, bioactive compounds, and volatile composition were studied. Sucrose, concentrated pomegranate juice, concentrated grape juice, and honey were used to increase the initial sugar content. The produced PABs contained ethanol in concentrations ranging from 7.9 to 10.0% v/v and glycerol from 4.8 to 6.1 g L−1. A decrease in total phenolics content, free radical-scavenging activity, and total monomeric anthocyanin content was observed following fermentation. Total flavonoids content appeared to increase after fermentation only in the cases of concentrated pomegranate and grape juice addition. In general, 22 volatile compounds were identified in PABs (13 esters, 2 fatty acids, and 7 alcohols). Major compounds detected were 3-methyl-1-butanol, 2-methyl-1-butanol, 2-phenylethanol, and ethyl acetate. These findings demonstrate the production prospect of PABs with increased ethanol content, while elaborating on the importance of fermentation temperature and the differences between the selected types of added sugars on end-product composition.

Edible oleogels are oils structured with non-triglyceride networks, that can be used as alternative solid-like fats. The formation of olive oil oleogels structured with monoglycerides (10%, 15% and 20% MGs) and 15% MGs in combination with 5% phytosterols (PS) was investigated. Effects of storage time (0–14 d) and temperature (−20 °C, 5 °C and 25 °C) on physicochemical properties of oleogels were probed by polarized light microscopy, large deformation mechanical measurements (hardness, gel strength), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The inclusion of 5% PS into a MG-olive oil based (15%) matrix enhanced the hardness and gel strength of the PS-MG composite oleogels, due to the fact that the PS prevented a high-level organization of MGs, as evidenced by reduced melting enthalpy values, compared to oleogels formulated solely with MGs. The 15% MGs - 5% PS oleogels stored at −20 °C exhibited the strongest mechanical properties throughout storage. A gradual transformation of the crystalline morphology (sub-α to β-crystals) was also observed over time, as probed by microscopy and FTIR analysis. The rate of these changes was faster at higher storage temperatures due to enhanced mobility of the MG molecules.

The present study aimed to evaluate the polar phenolic content of dried dates from three varieties and to determine their polar phenol bioaccessibility, using a static model of in vitro digestion. Dried date total phenol content was 55–71 mg GAE/100 g; total flavanol content was 0.2–0.4 mg CE/100 g, total flavone/flavonol content was 8–14 mg RE/100 g. Dates from the Ajwa and Safawi varieties presented the higher total phenol and flavone/flavonol content as compared with dates from the Jomara variety. Flavonoids together with benzoic acids and cinnamic acids were present in all date varieties. Among the compounds identified, gallic acid predominated in Ajwa variety (4.56 ± 0.11 mg/100 g), caffeic acid in Safawi (3.59 ± 0.02 mg/100 g), and neochlorogenic acid in Jomara (1.05 ± 0.10 mg/100 g). Simulated gastrointestinal digestion revealed that date polar phenols were bioaccessible. A 37–70% release was observed post oral digestion, in terms of total phenolic content, that further increased post gastric (> 100%). Total phenols and total flavones/flavonols were found to enter the simulated epithelial cell wall. p-Coumaric acid, ferulic acid, myricetin, and quercetin were identified and quantified in all simulated digestion phases.

The objective of this project was to ferment lactose and whey to ethanol in one-step process. Models of cell factory of non-engineered S.cerevisiae have been proposed to ferment lactose. The cell factory of non-engineered S. cerevisiae/SG-lactase was prepared by the addition, of a starch gel solution containing lactase on non-engineered S. cerevisiae, and freeze drying of it. The 2-layer non engineered S.cerevisiae-TC/SG-lactase factory was prepared by immobilizing S. cerevisiae on the internal layer of tubular cellulose (TC), and the lactase enzyme was contained in the upper layer of starch gel (SG) covering cells of S. cerevisiae. Using such cell factory for the fermentation of lactose, alcohol yield of 23-32 mL/L at lactose conversion of 71-100%. The improvement in alcohol yield by cell factory versus co-immobilization of lactase enzyme and S. cerevisiae on alginates, was found in the range of 28-78%. Likewise, the cell factories are more effective than engineered S. cerevisiae. The fermentation of whey instead of lactose resulted in a significant reduction of the fermentation time. Freeze-dried cell factories led to improved results as compared with non-freeze dried. When lactase was substituted with L. casei, ethanol and lactic acid were produced simultaneously at high concentrations, but in a much longer fermentation time. The cell factories can be considered as models for white biotechnology using lactose containing raw materials. This suggested cell factory model can be applied for other bioconversions using the appropriate enzymes and cells, in the frame of White Biotechnology without genetic modification.

In this study, an effort was made to create a model cell factory of Saccharomyces cerevisiae using bacterial cellulose (BC) and Aspergillus awamori for consolidated bioprocessing (CBP) of starch. This work suggested development of a cell factory for consolidated bioprocessing of starch in one bioreactor, performing three bioprocesses, i.e. production of amylolytic enzymes by fungal culture, hydrolysis of starch and fermentation to ethanol production using S. cerevisiae without its genetic modification. The microorganisms were separately immobilized on different amounts of BC and their mixture was used for the fermentation of 5% w/v starch. The mixture of BC/A. awamori and BC/S. cerevisiae was used for starch fermentation both in wet and freeze-dried (lyophilized) form in the same ratio (3:1). A 1.75-fold increase in maximum ethanol production was observed using freeze-dried BC immobilized biocatalysts compared to wet cell factory. The ethanol production yield was examined progressively by the effect of (i) initial ratios of both freeze-dried BC/S. cerevisiae and BC/A. awamori, (ii) different weight of the freeze-dried cell factory and (iii) A. awamori cells concentration, reaching the 82% of the theoretical yield encouraging us to use this cell factory model for further fermentations of starch in higher concentration. Ethanol production of 26.69 mL/L and the maximum ethanol yield (0.42 g ethanol/g starch) or 82% of the theoretical yield was achieved by increasing cells of A. awamori inoculum during its immobilization on BC to 10⁹ cells/mL. The results of this work are satisfactory compared with other systems of starch fermentation from literature. SEM, TEM and FTIR spectra analysis were carried out in order to prove the successful preparation of cell factory. SEM showed the immobilization of cells on the BC netting, and TEM showed on BC fibrils. Finally, a repeated fermentation batch was performed, proving the operational viability and stability of the cell factory. The results indicated that the objective of designed cell factory was successfully performer, and the results of starch fermentation are promising for the development of an innovation in brewing industry. Likewise, these have prospects of their application in White-Biotechnology.

The exploitation of starchy wastes for the production of value-added products and the consolidated bioprocessing (CBP) have a positive environmental and cost-effective impact. For this reason, a cell factory (CF) was employed to perform three bioprocesses in one step (CBP) for alcoholic fermentation of starch without genetic modification. CF is a bilayer biocatalyst consisting of an inner layer of immobilized Saccharomyces cerevisiae on tubular cellulose (TC) and an external layer of immobilized Aspergillus awamori on alginates (ALG). In first, the suggested CF was proved to be more effective compared with co-immobilized S. cerevisiae and A. awamori on ALG beads for starch fermentation. Subsequently, the effect of the (i) S. cerevisiae concentration (g S. cerevisiae/g TC) during its immobilization, (ii) CaCl ₂ concentration (% w/v), (iii) form of bilayer CF (wet or freeze-dried) and (iv) freeze-dried CF concentration on 5% (w/v) starch fermentation was examined. It was found that the higher ethanol production (32.17 mL/L), productivity (4.60 mL/L/d) and yield (0.51 g ethanol/g starch) reaching the theoretical one were obtained when the CF in freeze dried form fermented 100 mL of 5% (w/v) starch solution. Finally, two repeated fermentation batches were performed using the best CF. The ethanol yield was decreased during the repeated fermentation batches, but remained in acceptable levels. The successful preparation of CF was verified with FTIRspectroscopy, SEM and TEM analysis. The results indicated that the objective of designing CF was successfully achieved, and the results are promising to be the base for the exploitation of starchy wastes and the development of an innovation in brewing industry by eliminating the malting stage. This CF can be applied as model for different bioprocesses of White Biotechnology, e.g. substituting S. cerevisiae with the appropriate microorganism to produce other metabolites of added value.

The quality and safety of juices are assured mainly through heat treatments and chemical preservatives. However, there is a growing trend in the food industry for lowering energy and water demands, and the chemicals and additives that may have negative effects οn human health. Following that trend, in the present study, the reduced use of chemical preservatives in orange juice is proposed by using encapsulated sodium benzoate (SB) in tubular cellulose (TC), derived from orange pulp. The effects of SB concentration and contact time on SB encapsulation were evaluated. The use of the wet impregnation method, 12% w/v SB solution and 2 h of contact proved to be ideal for application in the juice industry. The use of starch gel resulted in a more stable composite (TC/SB-SG) with a slower SB delivery, showing its potential for future controlled delivery applications. Furthermore, similar delivery rates of SB in juice were noted at 25 and 2 °C. The TC/SB-SG proved capable of inhibiting the growth and reducing the numbers of spoilage microorganisms (yeasts and lactic acid bacteria). The results of the present study are promising for potential applications; however, more research is needed in order to evaluate the controlled delivery of SB in juice. 

The aim of this study is the consolidated bioprocessing of lactose into lactic acid and ethanol using non-engineered Cell Factories (CFs). Therefore, two different types of composite biocatalysts (CF1-CF2) based on Saccharomyces cerevisiae with immobilized microorganism or enzyme on starch gel (SG) were prepared for 5% w/v lactose fermentation. In CF1, S. cerevisiae was covered with SG containing Lactobacillus casei, Lactobacillus bulgaricus, Kluyveromyces marxianus CF1a-c. S. cerevisiae/SG-β-galactosidase (CF1d) was also used for simultaneous saccharification and fermentation (SSF) of lactose. In CF2, S. cerevisiae immobilized on tubular cellulose (TC) was covered with SG containing the aforementioned microorganisms (CF2a-c). The wet CF1d resulted in 96% of the theoretical ethanol yield while the wet CF1b and freeze-dried CF2b resulted in 89% of the theoretical lactic acid yield. The repeated batches using the CF2a-c exhibited better results than using CF1a-c. Subsequently, the freeze-dried CF2 as preservative and more manageable were verified for future exploitation of whey.

Biosurfactants constitute amphiphilic molecules, receiving increased attention as environmentally benign, biodegradable alternatives to substitute for the petroleum derived counterparts in food, pharmaceutical and cosmetics applications. However, their high production cost hinders industrial production. In this study, fifty GRAS lactobacilli strains were screened for their ability to produce biosurfactants, implementing different substrates. Cheese whey permeate (CWP) was also assessed as a low-cost and inherent lactobacilli substrate, aiming to mitigate its polluting impact, expand valorization strategies, alleviate costs deriving from commercial supplements and enhance overall sustainability. Surface tension, emulsification activity (E24) and oil displacement were deployed to identify the most promising candidates. Results reveal surface tension as the most robust method and underline the effect of substrate on biosurfactant synthesis. Likewise, this study indicates the fundamental role of including the final fermentation substrate (CWP) during strain selection to avoid misinterpretation of results and enhance subsequent bioprocess integration.

Background: Gut microbiota holds a key-role in numerous biological functions and has emerged as a driving force for the development of diabetes. Diet contributes to gut microbiota diversity and functionality providing a tool for the prevention and management of the disease. The study aimed to investigate the effect of a dietary intervention with pistachio nuts, a rich source of monounsaturated fatty acids, dietary fibers and phytochemicals on gut microbiota composition in the rat model of Type 1 Diabetes.

An integrated biorefinery has been developed using orange peel waste derived from catering services. Free sugars, essential oils and a phenolic-rich extract were initially separated from the orange peels. Liquid chromatography–mass spectrometry analysis showed that the phenolic-rich extract contained mainly quinic acid followed by hesperidin and hesperetin. Pectin was extracted from the remaining orange peel residues via dilute HCl or citric acid treatment followed by pectin precipitation with ethanol leading to pectin-rich extracts with pectin purity up to 54% (w/w). Process design showed that 62% lower energy consumption could be achieved in the pectin separation process when the pectin-rich liquid extract derived via HCl treatment is concentrated at 25% of the original volume prior to pectin precipitation via ethanol treatment. The pectin-free solid residue was subjected to hemicellulose (72.5%) and cellulose (70.4%) hydrolysis via sequential diluted H2SO4 pretreatment and enzymatic hydrolysis. Sugars derived from orange peels were used in Komagataeibacter sucrofermentans cultures in tray bioreactors under air sparging leading to 11.6 g/L bacterial cellulose concentration with productivity of 1.55 g/L/day. The proposed biorefinery led to the production of 1.5 kg essential oils, 1.3 kg phenolic-rich extract, 34 kg pectin-rich extract and 68 kg bacterial cellulose from 1 t of orange peel waste.

The industrial finishing of currants generates a considerable amount of side-stream (FSS) with great potential for biotechnological exploitation. The chemical composition, volatilome and antioxidant capacity of the FSS generated from the premium quality Vostitsa (Corinthian) currants was studied. Its use for wine making (at low temperatures, using both free and immobilized cells of an alcohol resistant and cryotolerant yeast strain) combined with baker’s yeast production, was also evaluated.

Pomegranate (Punica granatum L.) is an ancient fruit that is particularly cultivated in west Asia, though it is also cultivated in the Mediterranean region and other parts of the world. Since ancient years, its consumption has been associated with numerous health benefits. In recent years, several in vitro and in vivo studies have revealed its beneficial physiological activities, especially its antioxidative, antimicrobial and anti-inflammatory properties. Furthermore, human-based studies have shown promising results and have indicated pomegranate potential as a protective agent of several diseases. Following that trend and the food industry’s demand for antioxidants and antimicrobials from natural sources, the application of pomegranate and its extracts (mainly as antioxidants and antimicrobials), has been studied extensively in different types of food products with satisfactory results. This review aims to present all the recent studies and trends in the applications of pomegranate in the food industry and how these trends have affected product’s physicochemical characteristics and shelf-life. In addition, recent in vitro and in vivo studies are presented in order to reveal pomegranate’s potential in the treatment of several diseases.

In the present study, three commercial yeasts (for wine, beer, and cider) were evaluated for the production of pomegranate alcoholic beverage (PAB) from a juice of Wonderful variety. The physicochemical characteristics, antioxidant activity, and aromatic profiles of PABs were investigated before and after fermentation, while the effect of yeast strain and fermentation temperature (15 and 25 °C) was also evaluated. The PABs contained ethanol in the ranges of 5.6–7.0% v/v, in combination with glycerol (2.65–6.05 g L−1), and low volatile acidity. Total flavonoid content, total phenolic content, free radical-scavenging activity, and total monomeric anthocyanin content appeared to decrease after fermentation, possibly due to hydrolysis, oxidation, and other reactions. In general, PABs retained 81–91% of free radical-scavenging activity, 29–41% of phenolics, 24–55% of flavonoids, and 66–75% of anthocyanins. The use of different yeast affected mainly flavonoids and anthocyanins, and yeast strain M02 resulted in the highest values after fermentation. In PABs, 30 different volatile compounds were identified, specifically 15 esters, 4 organic acids, 8 alcohols, and 3 terpenes. The principal component analysis showed that the fermentation temperature affected significantly volatile composition, whereas, among the yeasts, WB06 is the one that seems to differentiate. The findings of this study show that the selection of the appropriate yeast and fermentation temperature is very crucial and affects the characteristics of the final product.

Fermentation, as a process to increase the security of food supply, represents an integral part of food culture development worldwide. Nowadays, in the evolving functional food era where new sophisticated technological tools are leading to significant transformations in the field of nutritional sciences and science-driven approaches for new product design, fermentation technology is brought to the forefront again since it provides a solid foundation for the development of safe food products with unique nutritional and functional attributes. Therefore, the objective of the present review is to summarize the most recent advances in the field of fermentation processes related to cereal-based products. More specifically, this paper addresses issues that are relevant to nutritional and health aspects, including their interrelation with intestinal (gut) microbiome diversity and function, although clinical trials and/or in vitro studies testing for cereal-based fermented products are still scarce.

Whey proteins are globular milk proteins with numerous functional properties and a broad potential for usage in food and supplement-pharmaceutical products. Under various denaturing conditions, whey proteins unfold, form aggregates, microparticles, while at sufficiently high concentrations, gel networks are created. The continuously growing research interest makes it necessary to discuss the recent advances and achievements in this area, including the basic principles of the structural assembly’s kinetics along with the different approaches undertaken to fabricate whey protein gels as well as the means to modulate the gel physical properties. This article also focuses on the use of ethanol to modify the structure and functionality of whey proteins, as an alternative way to change the protein conformation and thereby gelation phenomena and functionality.

Kefir is a rich source of potentially probiotic bacteria. In the present study, firstly, in vitro screening for probiotic characteristics of ten lactic acid bacteria (LAB) isolated from kefir grains was performed. Strain AGR 4 was selected for further studies. Molecular characterization of strain AGR 4, confirmed that AGR 4 belongs to the Lactobacillus paracasei (reclassified to Lacticaseibacillus paracasei subsp. paracasei) species. Further testing revealed that L. paracasei AGR 4 displayed adhesion capacity on human adenocarcinoma cells, HT-29, similar to that of the reference strain, L. casei ATCC 393. In addition, the novel strain exerted significant time- and dose-dependent antiproliferative activity against HT-29 cells and human melanoma cell line, A375, as demonstrated by the sulforhodamine B cytotoxicity assay. Flow cytometry analysis was employed to investigate the mechanism of cellular death; however, it was found that AGR 4 did not act by inducing cell cycle arrest and/or apoptotic cell death. Taken together, these findings promote the probiotic character of the newly isolated strain L. paracasei AGR 4, while further studies are needed for the detailed description of its biological properties.