Bibliometric analysis of water kefir and milk kefir in probiotic foods from 2013 to 2022: A critical review of recent applications and prospects

Bacterial viability retention in probiotic foods: a review

Probiotics offer substantial health benefits, leading to their increased consumption in various food products. The viability of probiotics is a critical factor that influences the nutritional and therapeutic efficacy of these foods. However, as probiotics often lose viability during production and oral administration, effective preservation and encapsulation technologies are needed to overcome this challenge. This review elucidates the diverse sources and incorporation strategies of probiotics, while systematically analyzing the effects of water transformation (ice front velocity, glass transition temperature, and collapse temperature), processing conditions (food matrix, temperature, and dissolved oxygen), and gastrointestinal challenges (gastric fluid, digestive enzymes, and bile salts) on probiotic viability. Effective strategies to strengthen probiotic viability encompass three primary domains: fermentation processes, production techniques, and encapsulation methods. Specifically, these include meticulous fermentation control (nitrogen sources, lipids, and carbon sources), pre-stress treatments (pre-cooling, heat shock, NaCl stress, and acid stress), optimized lyoprotectant selection (carbohydrates, proteins, and polyols), synergistic freeze-drying technologies (infrared technology, spray drying, and microwave), bulk encapsulation approaches (polysaccharide or protein-based microencapsulation), and single-cell encapsulation methods (self-assembly and surface functionalization). Despite these advancements, targeting specific probiotics and food matrices remains challenging, necessitating further research to enhance probiotic viability.

Probiotic Kefir Improves Renal Disorders in Ovariectomized Female SHR with High Fructose Intake-Induced Metabolic Syndrome

Women in postmenopausal period may present several comorbidities linked to metabolic syndrome (MetS). Our hypothesis is that kefir may prevent the deleterious effects in renal function in an experimental model of metabolic syndrome (MetS) and ovarian hormone deficiency. Young female spontaneously hypertensive rats (SHR) were divided into four groups: ovariectomized (OVX) control, OVX fructose, OVX kefir, and OVX kefir + fructose. They received kefir (5% w/v) via gavage for 8 weeks, while fructose (10% w/v) was available ad libitum. In ponderal parameters and glucose metabolism, we observe that fructose-overloaded groups (OF and OKF) showed increased weight, visceral fat, and fasting blood glucose. However, OKF partially reduced glycemic peak in the glucose tolerance test. Moreover, the standard method for the measurement of renal function showed that OF and OKF groups had a reduction in glomerular filtration rate, and surprisingly OKF exhibited increased renal flow (RBF and RPF) and decreased resistance (RVR). These might be associated with the findings in oxidative stress and nitric oxide (NO) bioavailability, in which kefir in the OKF group was capable of increasing total nitrogen oxides (NOx), attenuate the generation of hydrogen peroxide (DCF) and peroxynitrite (HPF), and also decreased the elevated microalbuminuria promoted by fructose even though the systemic blood pressure between the groups did not differ. Taking together our results, in the present study, kefir showed favorable effects in the model of metabolic syndrome and ovarian hormone deficiency (OKF), potentially protecting the kidney from the deleterious effects of fructose.

Evaluating the Impact of Kefir Consumption on Dental Caries and Periodontal Disease: A Narrative Review

Background/Objectives: Dental caries and periodontal diseases are the most common illnesses in the oral cavity and represent a public health concern globally. In recent decades, diverse studies showed that Kefir, a traditional beverage that can be milk- or water-based, contains a complex microbial community and has health benefits. The goal of this review was to update the current knowledge of kefir consumption and its impact on oral health. Methods: The search of a combination of keywords-kefir; dental caries; probiotics; microbiota; periodontal diseases; biofilm; and oral health-was conducted using PubMed, Google Scholar, and Web of Science databases for studies in human subjects. Discussion: The research suggests that kefir consumption may aid in decreasing counts of microorganisms typically associated with oral illness. Conclusions: Kefir has the potential to inhibit certain oral pathogens and reduce biofilm formation by promoting diversity within the oral microbiota, suggesting that kefir could be a promising adjuvant treatment for dental caries and periodontal diseases by improving oral health.

Effect of Milk and Water Kefir Grains on the Nutritional Profile and Antioxidant Capacity of Fermented Almond Milk

Today, the global trend toward plant-based beverages has grown for sustainability, health-related, lifestyle, and dietary reasons. Among them, drinks produced from almonds have been recognized as a concentrated nutrient source. Commercial almond milk was fermented under the same processing conditions using water and milk kefir grains to determine the starter culture leading to the beverage with the better nutritional profile. The resulting fermented beverages were investigated for protein, phenolic, and flavonoid content, fatty acid profile, and antioxidant activity, determined by DPPH, ABTS, and FRAP assays. Comparing the results, it was found that the almond beverage from milk kefir grains had the highest protein. The lipid profile of both beverages was characterized by a high content of monounsaturated fatty acids and a lower saturated fatty acid concentration compared to almond milk. Despite the higher phenolic content of the almond beverage from milk kefir grains, the ABTS and DPPH tests showed increased antioxidant activity in both fermented beverages, but with no significant difference between them, while the FRAP test showed a pronounced predominance of iron-reducing ability in the beverage from water kefir grains. The evidence from this study suggested that both types of grains can be used as starter cultures to enhance the nutritional and bioactive properties of almond milk.

Bibliometric Analysis of Probiotic Bacillus in Food Science: Evolution of Research Trends and Systematic Evaluation

With the in-depth and comprehensive research on probiotic Bacillus, it has become a hot topic in food science. However, the current status of research using bibliometric analysis to assess the application of probiotic Bacillus in food science has not been comprehensively reviewed. The Web of Science (WOS) database was used in this review's bibliometric analysis to determine the hotspots for research as well as the extent of completed experiments. Furthermore, a systematic review was conducted on the research hotspots of probiotic Bacillus in food science. The comprehensive analysis showed it was a growing and global research field. The keywords with high frequency mainly included "spore," "strain," and "production," which were research hot topics in the last decade. The application of the spore form or nutrient cells of probiotic Bacillus in industrialized food production through nutrient fortification, fermentation agents, and highly efficient synthesis of metabolites showed great development potential.

The intellectual base and research fronts of IL-18: A bibliometric review of the literature from WoSCC (2012-2022)

Interleukin-18 (IL-18) is a vital pro-inflammatory cytokine crucial for immune regulation. Despite its significance, bibliometric analysis in this field is lacking. This study aims to quantitatively and qualitatively assess IL-18 research to construct its intellectual base and predict future hotspots. We conducted a thorough search on the Web of Science Core Collection for relevant publications between 1 January 2012 and 31 December 2022. English-language articles and reviews were included. Visual analysis was performed using various tools including VOSviewer, Citespace, and Microsoft Excel. Our analysis covers interleukin-18 (IL-18) literature from 2012 to 2022, exploring research trends comprehensively. Key institutions like Yale University and Shanghai Jiao Tong University emerged as significant contributors. Prolific authors such as Kanneganti and Dinarello made notable contributions. Main focus areas included biology, medicine, and immunology. Co-citation analysis highlighted influential works like Jianjin Shi. Hotspot keyword frequency cluster analysis revealed emerging themes like pyroptosis and psoriasis. Gene co-occurrence clustering identified genes associated with immune regulation and inflammation. GO and KEGG pathway enrichment analysis provided insights into IL-18-related biological processes and pathways. Protein-protein interaction networks identified core proteins such as IL10 and TNF. Association disease analysis linked IL-18 to various inflammatory, autoimmune, and metabolic disorders. This bibliometric review offers insights into IL-18 research trends over the past decade, guiding future investigations and serving as a reference for researchers in this field.

Water kefir in co-fermentation with Saccharomyces boulardii for the development of a new probiotic mead

Mead is an alcoholic beverage obtained by fermenting a dilute solution of honey with yeasts. The aim of this study was to develop and evaluate a probiotic mead from the co-fermentation of water kefir and Sacharomyces boulardii. According to the results, the combination of 10 g/L of water kefir grains and 0.75 g/L of S. boulardii, with a fermentation time of 9 days, produced a probiotic mead with a viable cell count of more than 8 Log10 CFU/mL of S. boulardii and also for lactic acid bacteria, respectively. S. boulardii and lactic acid bacteria showed counts of over 6 Log10 CFU/mL after gastrointestinal simulation in vitro, with a survival rate of over 70%. Probiotic mead has good luminosity (L*), a tendency to yellow color and the presence of total phenolic compounds and antioxidants. In conclusion, the co-fermentation of water kefir and S. boulardii has potential for the development of probiotic mead.

Impact of Lyophilized Milk Kefir-Based Self-Nanoemulsifying System on Cognitive Enhancement via the Microbiota-Gut-Brain Axis

Chronic inflammatory bowel disorders (IBDs) are characterized by altered intestinal permeability, prompting inflammatory, oxidative stress, and immunological factors. Gut microbiota disorders impact brain function via the bidirectional gut-brain axis, influencing behavior through inflammatory cascades, oxidative stress, and neurotransmitter levels. This study highlights the potential effect of integrating lyophilized milk kefir alone and lyophilized milk kefir as solid carriers loaded with a self-nanoemulsifying self-nanosuspension (SNESNS) of licorice extract on an induced chronic IBD-like model in rats. Licorice-SNESNS was prepared by the homogenization of 30 mg of licorice extract in 1 g of the selected SNEDDS (30% Caraway oil, 60% Tween 20, and 10% propylene glycol (w/w)). Licorice-SNESNS was mixed with milk kefir and then freeze-dried. Dynamic TEM images and the bimodal particle size curve confirmed the formation of the biphasic nanosystems after dilution (nanoemulsion and nanosuspension). Daily oral administration of lyophilized milk kefir (100 mg/kg) loaded with SNESNS (10 mg/kg Caraway oil and 1 mg/kg licorice) restored normal body weight and intestinal mucosa while significantly reducing submucosal inflammatory cell infiltration in induced rats. Importantly, this treatment demonstrated superior efficacy compared to lyophilized milk kefir alone by leading to a more significant alleviation of neurotransmitter levels and improved memory functions, thereby addressing gut-brain axis disorders. Additionally, it normalized fecal microbiome constituents, inflammatory cytokine levels, and oxidative stress in examined tissues and serum. Moreover, daily administration of kefir-loaded SNESNS normalized the disease activity index, alleviated histopathological changes induced by IBD induction, and partially restored the normal gut microbiota. These alterations are associated with improved cognitive functions, attributed to the maintenance of normal neurotransmitter levels and the alleviation of triggered inflammatory factors and oxidative stress levels.

Bibliometric study and potential applications in the development of starch films with nanocellulose: A perspective from 2019 to 2023

This study aimed to perform a bibliometric analysis of starch films with nanocellulose, using the Scopus database and VOSviewer and Bibliometrix software. A total of 258 documents were identified between 2019 and 2023, reflecting a growing interest in research, particularly in journals such as the International Journal of Biological Macromolecules, Polymers, and Carbohydrate Polymers. The most common terms were "starch" (349 occurrences), "cellulose" (207), and "tensile strength" (175). China (58 articles), Brazil (38), and India (33) led scientific production, with authors like Ilyas (13 articles) and Sapuan (10) at the forefront. Approximately 41.7 % of the studies used corn starch. The analysis revealed that 66 % of the studies investigated films with cellulose nanofibrils (CNF), 32 % with cellulose nanocrystals (CNC), and 2 % with bacterial nanocellulose (CB). The majority of studies (94.1 %) used the casting method for film production. Additionally, 35.44 % focused on reinforcing films with nanocellulose, while 7 % developed blends with other biopolymers. About 59.44 % examined the performance of starch films for food packaging, 11.25 % explored practical applications in various foods. Furthermore, 7.94 % incorporated active agents to improve antioxidant and antimicrobial properties, 1.30 % investigated active packaging. Moreover, 2.36 % explored the use of films in materials engineering, and 2.36 % explored biomedical potential. Only 0.40 % evaluated the impact of films on wastewater treatment. The analysis highlights the potential of starch films with nanocellulose, demonstrating their diverse applications and the growing interest in the field.

Global dioxin research trends and focal points: A century-long visual and bibliometric analysis (1923-2022)

Dioxin-like compounds, recognized by the World Health Organization (WHO) as among the most enduring toxic chemical substances in the environment, are linked to various occupational activities and industrial accidents worldwide. The aim of this study was to examine and present research publications on dioxins, pinpoint current research trends, identify research gaps, and highlight potential avenues for future exploration in the field. The study period for relevant research articles ranged from 1923 to December 31, 2022, and these articles were sourced from the Scopus database. The analysis involved the identification of key contributors to the field and the visualization of topics, themes, and international collaboration. VOSviewer software (version 1.6.20) was used for visualization analysis. A total of 11,620 publications on dioxins were documented in the Scopus database. The predominant category of these documents comprised 9780 original articles, which represents 84.17% of the total publications. The United States lead in the number of publications, with 3992 (34.35%), followed by Japan, with 1429 (12.3%), China, with 1005 (8.65%), and Germany, with 974 (8.38%). Before 2002, scholarly attention in this field focused primarily on the health effects, environmental fate, and mechanism of toxicity of tetrachlorodibenzo-p-dioxin (TCDD). However, a noticeable change in research focus has been observed since 2002, highlighting the emergence of a topic related to the health effects and environmental fate of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PFDFs). This study is the first to conduct a comprehensive quantitative bibliometric analysis of dioxins over time. These findings indicate a significant increase in the overall growth of the dioxin literature over the past 30 years. These findings may prove crucial in guiding and organizing subsequent investigations related to dioxins.

The evaluation of black carrot, green cabbage, grape, and apple juices as substrates for the production of functional water kefir-like beverages

Water kefir (WK) is a nondairy probiotic beverage produced using water kefir grains that are highly adaptable to diverse food substrates. Fruit and vegetables have been used more in beverage production in recent years due to their plentiful nutritional qualities. In this context, the aim of this study is to develop fruit-vegetable juice-based beverages fermented with WK grains in order to produce novel, non-dairy, probiotic water kefir-like beverages (W-KLBs) with improved sensory and nutritional properties. In this context, black carrot (BC), apple (A), grape (G), and green cabbage (GC) juices are fermented with commercial WK grains. Results showed that BC-KLB possessed the highest antioxidant activity (75.50%), total phenolic (1248.60 mg GA/L), and total monomeric anthocyanin (391.31 mg/L as cyaniding-3-glucoside equivalent) content. Also, the sensory evaluation demonstrated that BC-KLB was the most favorable sample, while GC-KLB received negative feedback. These findings strongly support the suitability of BC juice to develop W-KLB with high added value and functional properties.

Challenges in water kefir production and limitations in human consumption: A comprehensive review of current knowledge

Water kefir is a convenient dairy-free alternative to dairy-based fermented beverages. It is prepared by fermenting a sucrose solution with fresh and dried fruits using water kefir grains, and demineralized whey can be used in water kefir production. This review describes current knowledge on water kefir production and its health effects. The main aims of this paper are to focus on the microbial composition, potential health-promoting properties, limitations in human consumption, and challenges in the production of water kefir. Water kefir grains and substrates, including brown sugar, dried and fresh fruits, vegetables, and molasses, used in the production influence the fermentation characteristics and composition of water kefir. Lactic acid bacteria, acetic acid bacteria, and yeasts are the microorganisms involved in the fermentation process. Lactobacillus species are the most common microorganisms found in water kefir. Water kefir contains various bioactive compounds that have potential health benefits. Water kefir may inhibit the growth of certain pathogenic microorganisms and food spoilage bacteria, resulting in various health-promoting properties, including immunomodulatory, antihypertensive, anti-inflammatory, anti-ulcerogenic, antiobesity, hypolipidemic, and hepatoprotective activities.

Microencapsulation to Harness the Antimicrobial Potential of Essential Oils and Their Applicability in Dairy Products: A Comprehensive Review of the Literature

This literature review explores cutting-edge microencapsulation techniques designed to enhance the antimicrobial efficacy of essential oils in dairy products. As consumer demand for natural preservatives rises, understanding the latest advancements in microencapsulation becomes crucial for improving the shelf life and safety of these products. The bibliometric analysis utilized in this review highlighted a large number of documents published on this topic in relation to the following keywords: essential oils, AND antimicrobials, AND dairy products, OR microencapsulation. The documents published in the last 11 years, between 2013 and 2023, showed a diversity of authors and countries researching this topic and the keywords commonly used. However, in the literature consulted, no study was identified that was based on bibliometric analysis and that critically evaluated the microencapsulation of essential oils and their antimicrobial potential in dairy products. This review synthesizes findings from diverse studies, shedding light on the various encapsulation methods employed and their impact on preserving the quality of dairy goods. Additionally, it discusses the potential applications and challenges associated with implementation in the dairy industry. This comprehensive analysis aims to provide valuable insights for researchers, food scientists, and industry professionals seeking to optimize the use of essential oils with antimicrobial properties in dairy formulations.

The composition of Tibetan kefir grain TKG-Y and the antibacterial potential and milk fermentation ability of S. warneri KYS-164 screened from TKG-Y

This study utilized high-throughput sequencing and SEM observation to elucidate the microbial composition of a Tibetan herder's homemade kefir grain named TKG-Y. Subsequently, S. warneri KYS-164 was isolated from TKG-Y, which can produce mixed protein substances with antibacterial activity, namely bacteriocin-like inhibitory substances (BLIS). BLIS can significantly reduce the growth rate of Escherichia coli 366-a, Staphylococcus aureus CICC 10384 and mixed strains at low concentrations (1 × MIC). The presence of the warnericin-centered gene cluster in KYS-164 may explain the antibacterial properties of the BLIS. Pepsin and an acidic environment can reduce the number of colonies of KYS-164 by 2.5 Log10 CFU mL-1 within 1 h, and reduce the antibacterial activity of BLIS by 21.48%. S. warneri KYS-164 showed no antibiotic resistance and biological toxicity after 80 subcultures, while BLIS produced by 40 generations of the strain retained their inhibitory efficacy against pathogenic bacteria. After 48-hour fermentation of milk with KYS-164, volatile compounds such as aldehydes, phenols, esters, and alcohols, giving it a floral, fruity, milky, oily, and nutty aroma, were released, enriching the sensory characteristics of dairy products. This study not only revealed the bacterial colony composition information of home-made kefir grain TKG-Y but also discovered and proved that S. warneri KYS-164 has the potential to inhibit bacteria and ferment dairy products. This will provide a basis for subsequent applied research on KYS-164.