Kombucha is widely recognized as a functional beverage with potential probiotic effects, yet maintaining probiotic viability remains a challenge due to the harsh conditions of fermentation. This study focuses on optimizing probiotic retention by identifying the most effective carrier for Lactobacillus rhamnosus using a multi-criteria decision-making approach. Five carrier materials—pea protein, whey protein, maltodextrin, inulin, and pectin—were assessed through three critical phases: evaluating encapsulated probiotic survival in different pH solutions, examining the impact of carriers on kombucha fermentation, and assessing probiotic stability during storage. The findings indicate that whey protein serves as the most effective carrier, offering superior bacterial protection and enhancing fermentation efficiency. Kinetic modeling further demonstrated a significant correlation between probiotic survival, pH, and titratable acidity, while artificial neural network models achieved high predictive accuracy (r² > 0.9). Functional analysis revealed that kombucha enriched with probiotic whey protein encapsulates exhibited improved bioactivity, including enhanced antidiabetic properties through α-glucosidase and α-amylase inhibition, antihypertensive effects via ACE inhibition, and antihypercholesterolemic activity through HMGCR inhibition. These findings suggest that probiotic fortification contributes to the beverage’s overall health-promoting potential. Sensory evaluation highlighted that while enriched kombucha exhibited slight modifications in texture and acidity, overall consumer acceptability remained high. The study underscores whey protein’s role as an optimal probiotic carrier, significantly enhancing kombucha’s probiotic stability and bio functional properties. The results contribute to advancements in functional beverage formulation, paving the way for the development of probiotic-enriched kombucha with improved stability, bioactivity, and consumer appeal.

The sustainable production of natural pigments is gaining attention as industries seek alternatives to synthetic additives. This study explored agro-industrial biowastes as feedstocks for carotenoid biosynthesis by Rhodotorula mucilaginosa (natural isolate from Jerusalem artichoke), aiming to identify an optimal substrate that combines high productivity with economic and environmental feasibility. Thirteen biowastes, including grape pomace, crude glycerol, chicken feathers, sugar beet juice, and pea protein isolate, were systematically evaluated for their impact on yeast growth and pigment accumulation. Carotenoid yields ranged from 21.4 to 187.2 mg/100 g dry weight, with the highest volumetric productivity achieved in pea protein isolate (14.98 mg/L), untreated white grape pomace (14.09 mg/L), and crude glycerol (13.87 mg/L). To assess scalability, a simplified techno-economic and sustainability analysis was applied, revealing that although pea protein isolate offered the best yields, its high market cost limited industrial feasibility. In contrast, untreated grape pomace and crude glycerol emerged as low-cost, abundant alternatives with strong circular bioeconomy potential. Fed-batch bioreactor validation using untreated grape pomace confirmed its suitability, achieving a 43% improvement in carotenoid productivity (20.1 mg/L) compared to shake-flask trials. These results position untreated grape pomace as the optimal substrate–strategy combination for sustainable carotenoid production linking agro-waste valorization with high-value bioproduct generation. This study provides both experimental evidence and economic rationale for integrating winery residues into industrial pigment production chains, advancing yeast biotechnology toward more circular and resource-efficient models.

Kombucha is a fermented tea beverage of Asian origin, widely consumed due to its functional properties; yet, it typically lacks sufficient levels of probiotic micro-organisms to be classified as a probiotic product. This review analyzes the occurrence of lactic acid bacteria (LAB) in kombucha, reporting that concentrations rarely exceed 4–5 log CFU/mL and often decline during fermentation or storage. Strategies to enhance probiotic viability, including the use of robust LAB strains and encapsulation technologies, are critically evaluated. Notably, encapsulation using pea and whey protein has been shown to sustain LAB levels above 6 log CFU/mL during fermentation and up to 21 days under refrigerated storage for whey protein. Fortified kombucha beverages with probiotic strains have also been shown to possess enhanced functional and health-promoting benefits compared to traditional control samples. Despite promising approaches, inconsistencies in microbial survival and regulatory constraints remain key challenges. Future research should focus on the optimization of delivery systems for probiotic cultures, identification of kombucha-compatible LAB strains and standardized protocols to validate probiotic efficacy in real-world beverage conditions.

Kombucha is a fermented beverage produced using a symbiotic consortium of acetic acid bacteria and yeasts, often marketed for its health-promoting properties. However, probiotic bacteria in kombucha are typically present at inconsistent levels and may not remain viable during fermentation. In this study, three Lactobacillus strains (Lacticaseibacillus rhamnosus ATCC 53103 (L. rhamnosus), Lactiplantibacillus plantarum subsp. plantarum ATCC 14917 (L. plantarum) and Lentilactobacillus hilgardii (L. hilgardii) isolate) were encapsulated in whey protein using the lyophilization method and added individually at the start of kombucha fermentation. Lactic acid bacteria (LAB)–enriched kombucha samples were evaluated for chemical composition (polyphenols, flavonoids, vitamin C and organic acids) and functional properties (antimicrobial, antiproliferative, antioxidant and anti-inflammatory activities) and compared to a traditionally obtained control kombucha, primarily demonstrating in vitro and experimental assessment. Encapsulation maintained LAB viability above 6–7 log CFU/mL throughout fermentation, producing kombucha with enhanced microbial stability. LAB–enriched samples exhibited increased L-lactic acid and antimicrobial activity. L. rhamnosus and L. hilgardii–enriched samples exhibited increased antiproliferative and anti-inflammatory activities, which may be associated with strain-dependent production of organic acids, polyphenol modulation and LAB-derived bioactive metabolites. Antioxidant activity varied depending on assay, and L. rhamnosus–enriched kombucha showed higher anti-inflammatory activity. These findings demonstrate that whey protein encapsulation can preserve LAB during fermentation, enhance specific bioactive properties and provide a platform for developing functional kombucha beverages with potential applications in the food industry.

Kombucha is a traditional beverage of Asian origin, usually prepared by fermenting sweetened black tea (Camellia sinensis L.) using a symbiotic consortium of acetic acid bacteria (AAB) and osmophilic yeasts (Symbiotic Consortium of Bacteria and Yeast - SCOBY). Kombucha exhibits several functional properties such as antimicrobial, antioxidant, antiproliferative, etc., however it usually cannot be labeled as a probiotic product since the number of probiotic microorganisms often does not reach the specified criteria of 6-8 log CFU/mL. Lactic acid bacteria (LAB) are one of the major bacteria used for probiotic purposes. Lthat exert health benefits should be able to survive sometimes harsh conditions during fermentation, processing and storage. Several microencapsulation methods are already being used to improve their viability in various matrices. In this study, the probiotic strain Lactobacillus rhamnosus ATCC 53103 was encapsulated in maltodextrin and pea protein using three different sample preparation methods prior to encapsulation by lyophilization. Based on encapsulation efficiency, method 3 was selected as the most effective and applied for further encapsulation using three additional carriers, two polysaccharides (pectin and inulin) and one protein (whey). The dissolution behavior, LAB viability and release kinetics of the obtained capsules was then investigated in different media (physiological saline, sodium citrate, and KH₂PO₄). The results indicated that physiological saline provided the most stable conditions. Finally, the stability of encapsulated Lwas evaluated in finalized kombucha during storage. Among the tested carriers, whey protein showed the best ability to protect Lcells and maintain their viability, although its stability was limited to 10 days. In other carriers, Lsurvival was significantly reduced.