Kefir as a Functional Beverage Gaining Momentum towards Its Health Promoting Attributes

The consumption of fermented foods posing health-promoting attributes is a rising global trend. In this manner, fermented dairy products represent a significant subcategory of functional foods with established positive health benefits. Likewise, kefir—a fermented milk product manufactured from kefir grains—has been reported by many studies to be a probiotic drink with great potential in health promotion. Existing research data link regular kefir consumption with a wide range of health-promoting attributes, and more recent findings support the link between kefir’s probiotic strains and its bio-functional metabolites in the enhancement of the immune system, providing significant antiviral effects. Although it has been consumed for thousands of years, kefir has recently gained popularity in relation to novel biotechnological applications, with different fermentation substrates being tested as non-dairy functional beverages. The present review focuses on the microbiological composition of kefir and highlights novel applications associated with its fermentation capacity. Future prospects relating to kefir’s capacity for disease prevention are also addressed and discussed

Cheese whey processing: integrated biorefinery concepts and emerging food applications

Cheese whey constitutes one of the most polluting by-products of the food industry, due to its high organic load. Thus, in order to mitigate the environmental concerns, a large number of valorization approaches have been reported; mainly targeting the recovery of whey proteins and whey lactose from cheese whey for further exploitation as renewable resources. Most studies are predominantly focused on the separate implementation, either of whey protein or lactose, to configure processes that will formulate value-added products. Likewise, approaches for cheese whey valorization, so far, do not exploit the full potential of cheese whey, particularly with respect to food applications. Nonetheless, within the concept of integrated biorefinery design and the transition to circular economy, it is imperative to develop consolidated bioprocesses that will foster a holistic exploitation of cheese whey. Therefore, the aim of this article is to elaborate on the recent advances regarding the conversion of whey to high value-added products, focusing on food applications. Moreover, novel integrated biorefining concepts are proposed, to inaugurate the complete exploitation of cheese whey to formulate novel products with diversified end applications. Within the context of circular economy, it is envisaged that high value-added products will be reintroduced in the food supply chain, thereby enhancing sustainability and creating “zero waste” processes

Production of a Novel Functional Fruit Beverage Consisting of Cornelian Cherry Juice and Probiotic Bacteria

The present study describes the development of a novel functional beverage through the application of probiotic Lactobacillus plantarum ATCC (American Type Culture Collection) 14917 in Cornelian cherry juice fermentation. The probiotic was employed in free and immobilized in a delignified wheat bran carrier (DWB) form. Cornelian cherry juice was fermented for 24 h and then it was stored at 4 °C for 4 weeks. Several parameters were evaluated such as residual sugar, organic acid and alcohol levels, total phenolics content, and cell viability as well as consumers acceptance. Regarding sugar and organic acids analyses, it was proved that the probiotic free or immobilized biocatalyst was effective. The concentration of ethanol was maintained at low levels (0.3–0.9% v/v). The total phenolic content of fermented Cornelian cherry juice with immobilized cells was recorded in higher levels (214–264 mg GAE/100 mL) for all the cold storage time compared to fermented juice with free cells (165–199 mg GAE/100 mL) and non-fermented juice (135–169 mg GAE/100 mL). Immobilized cells retained their viability in higher levels (9.95 log cfu/mL at the 4th week) compared to free cells (7.36 log cfu/mL at the 4th week). No significant sensory differences were observed among the fermented and the non-fermented samples

Technological Development of Brewing in Domestic Refrigerator Using Freeze-Dried Raw Materials

U radu je prikazan razvoj novog tipa piva za tržiste, koje se dobiva vrenjem pri niskoj temperaturi u hladnjaku s pomoću imobiliziranog kvasca. Zamrznuta sladovina te stanice soja kvasca Saccharomyces cerevisiae AXAZ-1, koji je otporan na smrzavanje, imobilizirane su na cijevnom modulu i zasebno upotrijebljene za vrenje pri niskim temperaturama (2, 5 i 7 °C). Ispitan je pozitivan učinak cijevnog modula na vrenje pri niskim temperaturama, te je utvrđeno da smrznute imobilizirane stanice kvasca na cijevnom modulu bitno smanjuju brzinu vrenja u usporedbi sa smrznutim slobodnim stanicama, koje su preporučene za proizvodnju piva kod kuće. Imobilizacija je također povećala otpornost kvasca na niske temperature vrenja, pa se najniža moguća temperatura vrenja spustila s 5 na 2 °C. Pri proizvodnji visokokvalitetnog piva ispitani su sljedeći parametri: utjecaj temperature i početne koncentracije šećera na kinetiku vrenja. Analizom gotovog proizvoda potvrđeno je poboljšanje senzorskih svojstava proizvedenog piva, s niskom koncentracijom diacetila, povećanim udjelom polifenola, te poboljšanim profilom arome i bistroćom. Predloženi postupak proizvodnje piva u hladnjaku može se lako komercijalizirati za kućnu uporabu otapanjem sadržaja dvaju pakiranja, jednog sa suhom sladovinom i drugog sa suhim stanicama kvasca imobiliziranim na cijevnom modulu i otopljenim u vodi.Development of a novel directly marketable beer brewed at low temperature in a domestic refrigerator combined with yeast immobilization technology is presented in this study. Separately, freeze-dried wort and immobilized cells of the cryotolerant yeast strain Saccharomyces cerevisiae AXAZ-1 on tubular cellulose were used in low-temperature fermentation (2, 5 and 7 °C). The positive effect of tubular cellulose during low-temperature brewing was examined, revealing that freeze-dried immobilized yeast cells on tubular cellulose significantly reduced the fermentation rates in contrast to freeze-dried free cells, although they are recommended for home-made beer production. Immobilization also enhanced the yeast resistance at low-temperature fermentation, reducing the minimum brewing temperature value from 5 to 2 °C. In the case of high-quality beer production, the effect of temperature and initial sugar concentration on the fermentation kinetics were assessed. Sensory enrichment of the produced beer was confirmed by the analysis of the final products, revealing a low diacetyl concentration, together with improved polyphenol content, aroma profile and clarity. The proposed process for beer production in a domestic refrigerator can easily be commercialized and applied by dissolving the content of two separate packages in tap water; one package containing dried wort and the other dried immobilized cells on tubular cellulose suspended in tap water

Bioprocesses for the production of probiotic dairy products with the use of immobilized cells on prebiotic carriers

Worldwide food market is displaying an increased demand for functional foods that contain technologically developed novel ingredients that have beneficial health effects. In addition, new approaches have been developed in order to satisfy the consumer’s needs for healthier, safe and high quality dairy products. Probiotic dairy products are among the main suggested types of food that can provide numerous nutritional benefits to consumers. Various studies have reported that the use of probiotic bacteria, especially Lactobacilli strains, can offer health benefits to the host when administered at appropriate amounts (106-107 CFU/g). Thus, the main objective of the present thesis was the production of novel immobilized probiotic biocatalysts that can be used for functional dairy food production. More specifically, prebiotic carriers (wheat bran, delignified wheat bran, corn, sea buckthorn berries and yellow split peas) were used for the immobilization of lactobacilli and after that for the production of probiotic dairy products. All immobilized biocatalysts and free cells were previously freeze dried without any cryoprotectants and tested for their viability. All prebiotic carriers were proved to have a protective effect on the viability of immobilized lactobacilli cells. The effect of the immobilized biocatalysts to the physicochemical, microbiological, volatile and sensory characteristics of the produced dairy products was also studied. In first, white brine cheeses were produced. The probiotic microorganism L. casei ATCC 393 was immobilized on wheat bran, delignified wheat bran, corn, sea buckthorn berries and yellow split peas for the production of Feta type brine cheeses. For comparison reasons free cells of L. casei were also used for cheese production. Wheat bran is a mills by-product with a high nutritional value and prebiotic effects. Delignification of wheat bran resulted to higher immobilized cell viability of L. casei when incorporated into Feta type cheese products. Based on this observation, the potentially probiotic strain L. paracasei K5, isolated from Greek dairy products, was also immobilized on delignified wheat bran and used for the production of white brine cheeses. All immobilized biocatalysts incorporated in white brine cheeses imparted exceptional organoleptic characteristics to the manufactured products with high lactobacilli viability (>106 CFU/g). No pathogens were detected in white brine cheeses after the 60th storage day so the cheeses were ready for consumption. Moreover, sea buckthorn berries used as cell carrier introduced antimicrobial attributes and minimized earlier spoilage in Feta cheese compared with the other immobilized biocatalysts probably due to their higher terpene content. Secondly, probiotic yogurts were produced by incorporation of free and/or immobilized L. casei and L. bulgaricus cells on wheat bran and delignified wheat bran. At first, L. casei and L. bulgaricus cells were grown in cheese whey after the removal of protein content. This procedure was proved to be slower than the classic lactobacilli cultivation but is certainly a cheaper process since an industrial by-product is used, i.e. whey, which is a major liquid effluent of the dairy industry. Moreover, the immobilization process was also carried out in whey giving good quality immobilized biocatalysts. After freeze drying, the immobilized L. casei and L. bulgaricus biocatalysts (1:1) and free ones were added in milk for the production of probiotic yogurt. The immobilized biocatalysts were either removed when the pH reached the value 4.6 or were maintained in yogurts for 30 days of storage at 4oC. All produced yogurts showed good physicochemical, organoleptic, volatile and microbiological characteristics, with complete absence of pathogenic microorganisms during their storage at 4 °C for 30 days. Moreover, all yogurts showed high survival rates of immobilized and free L. casei cells (>107 cfu/g) during 30 days of storage (4oC) and so they were characterized as probiotics. Thirdly, probiotic sour milk was produced by incorporation of free and/or immobilized L. casei cells on wheat bran and delignified wheat bran. Each immobilized biocatalyst was either maintained in sour milk for 30 storage days at 4oC or was removed when the pH reached 4.5. All sour milk products were characterized as probiotics (>107 CFU/g) and showed good physicochemical, organoleptic, volatile and microbiological characteristics during 30 days of storage (4 °C). Finally, continuous production of probiotic yogurt and probiotic sour milk was assessed in a 1.5 L bioreactor with milk supplied at a flow rate of 1 L/hour. For continuous yogurt production, L. casei and L. bulgaricus were separately immobilized on delignified wheat bran, freeze dried and used at a ratio 1:1. The system was monitored regarding pH during passage of 5 liters of milk at 40oC. At the end of each operation hour, 1 liter of effluent milk was received in a sterile glass container and was left for coagulation at 40oC until pH 4.6. Totally 5 parts (1 liter each) of effluent milk were received separately. After passage of this amount of milk no viable L. bulgaricus cells were detected. The number and the concentration of volatile by-products decreased in yogurts as the received volume of effluent milk increased. The products showed good physicochemical, organoleptic and microbiological characteristics during their storage at 4 °C for 30 days. Moreover, all yogurts showed high survival rates L. casei cells (>107 cfu/g) and were characterized as probiotics. For continuous sour milk production, L. casei cells were immobilized on delignified wheat bran and freeze dried. The freeze dried immobilized biocatalyst was introduced in the bioreactor and was used to ferment in total 10 liters of milk. The system was monitored regarding pH during passage of 10 L of milk at 37oC. At the end of each operation hour, 1 liter of effluent milk was received in a sterile glass container and remained for coagulation at 37oC until pH 4.5. Totally 10 parts of effluent milk were received separately. The products showed good physicochemical, organoleptic and microbiological characteristics during their storage at 4 °C for 30 days. The number and the concentration of volatile by-products of sour milk decreased with time in the milk effluents. Moreover, all products showed high survival rates of L. casei cells (>107 cfu/g) and so they were characterized as probiotics. In general, the continuous production of probiotic yoghurt and sour milk yielded promising results for industrial application of this technology while use of whey as a growth and immobilization substrate can result in high quality fermented dairy products with lower cost.Στο εισαγωγικό μέρος της διδακτορικής διατριβής δίνονται στοιχεία που αφορούν στο γάλα, στα ζυμωμένα γαλακτοκομικά προϊόντα, στα νέα τρόφιμα, στις μεθόδους ακινητοποίησης κυττάρων μικροοργανισμών, τους πριβιοτικούς φορείς ακινητοποίησης και τη λυοφιλίωση ως μέθοδο συντήρησης των μικροοργανισμών. Επίσης, γίνεται αναφορά στις κατηγορίες των γαλακτοκομικών προϊόντων καθώς και στις μικροβιολογικές και βιοχημικές μεταβολές κατά την ωρίμανσή τους, τις αρχικές καλλιέργειες που χρησιμοποιούνται καθώς και τη συμβολή τους στην ανάπτυξη του αρώματος. Ο κύριος στόχος της διατριβής αυτής ήταν η παραγωγή νέων λειτουργικών γαλακτοκομικών προϊόντων με ενισχυμένα οργανοληπτικά χαρακτηριστικά και προβιοτικό χαρακτήρα για βελτίωση της ποιότητας των προϊόντων αυτών καθώς και της υγείας του καταναλωτή. Σε αυτό το πλαίσιο, μελετήθηκε η παραγωγή προβιοτικών λευκών τυριών άλμης, προβιοτικών γιαουρτιών και προβιοτικού ξινογάλακτος με χρήση γαλακτικών βακτηρίων ακινητοποιημένων σε πριβιοτικούς φορείς. Οι φορείς ακινητοποίησης που χρησιμοποιήθηκαν ήταν διάφορα δημητριακά (απολιγνινοποιημένοι ή μη φλοιοί σιταριού, καλαμπόκι), όσπρια (φάβα) και καρποί ιπποφαούς οι οποίοι χρησιμοποιούνται πρώτη φορά ως υποστρώματα ακινητοποίησης προβιοτικών μικροοργανισμών. Οι ακινητοποιημένοι βιοκαταλύτες λυοφιλιώθηκαν δίχως τη χρήση κρυοπροστατευτικών και έπειτα χρησιμοποιήθηκαν προς παραγωγή γαλακτοκομικών προϊόντων. Για την παρασκευή των προβιοτικών γαλακτοκομικών προϊόντων επιλέχθηκε η χρήση του προβιοτικού στελέχους L. casei ATCC 393. Επίσης, στα εργαστήρια του Δημοκρίτειου Πανεπιστημίου Θράκης έγινε απομόνωση και μοριακή ταυτοποίηση ενός νέου στελέχους δυνητικώς προβιοτικού γαλακτικού βακτηρίου (L. paracasei K5) και ακολούθησε η ακινητοποίηση του σε απολιγνινοποιημένο φλοιό σιταριού και η χρήση του στην παραγωγή λευκού τυριού άλμης. Τα γαλακτοκομικά προϊόντα που παρήχθησαν μελετήθηκαν ως προς τα αρωματικά, φυσικοχημικά και οργανοληπτικά χαρακτηριστικά τους καθώς και ως προς την μικροβιολογική τους σταθερότητα. Επίσης, μελετήθηκε η επίδραση του εκάστοτε βιοκαταλύτη ως προς τον προβιοτικό χαρακτήρα των παραγόμενων γαλακτοκομικών προϊόντων. Τέλος, αξιολογήθηκε η συνεχής παραγωγή προβιοτικού γιαουρτιού και ξινογάλακτος με χρήση ακινητοποιημένων κυττάρων σε απολιγνινοποιημένους φλοιούς σιταριού σε σύστημα pilot plan. Μελετήθηκαν τα φυσικοχημικά χαρακτηριστικά των προϊόντων και ιδιαίτερα η επίδραση της διεργασίας στα αρωματικά συστατικά των προϊόντων έτσι ώστε να βρεθούν οι βέλτιστες συνθήκες παραγωγής σε συνδυασμό με την υψηλή ποιότητα των παραγόμενων προϊόντων. Στο πειραματικό μέρος της διδακτορικής διατριβής αναφέρονται οι μέθοδοι παραγωγής των προϊόντων και οι μέθοδοι και οι αναλυτικές τεχνικές που χρησιμοποιήθηκαν για τη παρακολούθηση αναλυτικών παραμέτρων των γαλακτοκομικών προϊόντων. Διαπιστώθηκε η καταλληλότητα του εκάστοτε ακινητοποιημένου βιοκαταλύτη ως προς τη πρόσδοση εξαιρετικών οργανοληπτικών χαρακτηριστικών στα παραγόμενα γαλακτοκομικά προϊόντα. Το ιπποφαές, που αποτέλεσε υπόστρωμα ακινητοποίησης περιείχε αυξημένη συγκέντρωση τερπενίων, που λόγω της αντιμικροβιακής τους δράσης προστατεύουν από αλλοίωση τα παραγόμενα προϊόντα. Μελετήθηκε η παραγωγή γιαουρτιών και ξινογάλακτος με τη χρήση ελεύθερων και ακινητοποιημένων κυττάρων L. casei σε απολιγνινοποιημένους και μη φλοιούς σιταριού. Τα υψηλά ποσοστά επιβίωσης των ακινητοποιημένων κυττάρων L. casei (>107) προσδίδουν στα παραγόμενα δείγματα γιαουρτιού και ξινογάλακτος τον χαρακτηρισμό προβιοτικού τροφίμου. Προβιοτικά επίσης χαρακτηρίζονται τα τυριά τύπου Φέτας που παρασκευάστηκαν με χρήση ακινητοποιημένων κυττάρων L. casei σε καρπούς ιπποφαούς, καλαμπόκι, φάβα, φλοιούς σιταριού και απολιγνινοποιημένους φλοιούς σιταριού. Δυνητικά προβιοτικά χαρακτηρίζονται τα τυριά άλμης που παρασκευάστηκαν με χρήση ακινητοποιημένων κυττάρων Lactobacillus paracasei Κ5 σε απολιγνινοποιημένους φλοιούς σιταριού. Όλα τα παραγόμενα προϊόντα παρουσίασαν καλά φυσικοχημικά, αρωματικά, οργανοληπτικά και μικροβιολογικά χαρακτηριστικά, με πλήρη απουσία παθογόνων μικροοργανισμών κατά τη διάρκεια αποθήκευσής τους για 30 ημέρες (4°C). Τέλος, η συνεχής παραγωγή προβιοτικού γιαουρτιού και ξινογάλακτος έδωσε ελπιδοφόρα αποτελέσματα για την βιομηχανική εφαρμογή της τεχνολογίας αυτής με παράλληλη αξιοποίηση του τυρογάλακτος ως υποστρώματος ανάπτυξης και ακινητοποίησης των αρχικών ακινητοποιημένων βιοκαταλυτών

Exploring Human Metabolome after Wine Intake—A Review

Wine has a rich history dating back to 2200 BC, originally recognized for its medicinal properties. Today, with the aid of advanced technologies like metabolomics and sophisticated analytical techniques, we have gained remarkable insights into the molecular-level changes induced by wine consumption in the human organism. This review embarks on a comprehensive exploration of the alterations in human metabolome associated with wine consumption. A great number of 51 studies from the last 25 years were reviewed; these studies systematically investigated shifts in metabolic profiles within blood, urine, and feces samples, encompassing both short-term and long-term studies of the consumption of wine and wine derivatives. Significant metabolic alterations were observed in a wide variety of metabolites belonging to different compound classes, such as phenolic compounds, lipids, organic acids, and amino acids, among others. Within these classes, both endogenous metabolites as well as diet-related metabolites that exhibited up-regulation or down-regulation following wine consumption were included. The up-regulation of short-chain fatty acids and the down-regulation of sphingomyelins after wine intake, as well as the up-regulation of gut microbial fermentation metabolites like vanillic and syringic acid are some of the most important findings reported in the reviewed literature. Our results confirm the intact passage of certain wine compounds, such as tartaric acid and other wine acids, to the human organism. In an era where the health effects of wine consumption are of growing interest, this review offers a holistic perspective on the metabolic underpinnings of this centuries-old tradition

Valorization of Lactic Acid Fermentation of Pomegranate Juice by an Acid Tolerant and Potentially Probiotic LAB Isolated from Kefir Grains

The present study describes the application of an acid tolerant and potentially probiotic L. paracasei SP3 strain, recently isolated from kefir grains, in the production of a novel functional beverage based on the fermentation of pomegranate juice. The fermentation ability of the novel strain was assessed during pomegranate juice fermentations at 30 °C for 24 h and storage at 4 °C for 4 weeks. Various parameters were assessed such as residual sugar, organic acid and alcohol levels, total phenolics content, antioxidant activity, astringency, cell viability, and consumer acceptance. Residual sugar was decreased by approximately 25%, while respectable amounts of lactic acid were determined (4.8 g/L) on the 28th day of storage, proving that the novel strain was effective at lactic acid fermentation. The concentration of ethanol was maintained at low levels (0.3–0.4 % v/v) and low levels of acetic acid were detected (0.6 g/L). The viability of L. paracasei SP3 cells retained high levels (>7 log cfu/mL), even by the 4th week. The total phenolic content (123.7–201.1 mg GAE/100 mL) and antioxidant activity (124.5–148.5 mgTE/100 mL) of fermented pomegranate juice were recorded at higher levels for all of the studied time periods compared to the non-fermented juice. The employment of the novel strain led to a significant reduction in the levels of hydrolysable tannins (42%) in the juice, reducing its astringency. The latter was further proven through sensorial tests, which reflected the amelioration of the sensorial features of the final product. It should be underlined that fruit juices as well as pomegranate juice comprised a very harsh food matrix for microorganisms to survive and ferment. Likewise, the L. paracasei SP3 strain showed a significant potential, because it was applied as a free culture, without the application of microencapsulation methods that are usually employed in these fermentations, leading to a product with possible functional properties and a high nutritive value