Development of fermented beverage with water kefir in water-soluble coconut extract (Cocos nucifera L.) with inulin addition

New plant-based kefir fermented beverages as potential source of GABA

The aim of this study was to assess the gamma-aminobutyric acid (GABA) production in plant-based fermented beverages with kefir cultures (milk and water kefir). Water-soluble extracts of peanut and Brazil nut were evaluated as non-dairy substrates for the development of new bioactive beverages. A total of 12 formulations were developed and evaluated for their chemical composition, physical chemical characterization, and microbiological counts (aerobic mesophilic bacteria, lactobacilli, lactococci and yeasts). Results proved that the composition of kefir culture, the nature of the extract and the addition of glutamic acid affected GABA production. Even peanut extracts presenting higher protein content, Brazil nut extracts was the best substrate for GABA production. In addition, fermented beverages were evaluated for in vitro antihypertensive activity through angiotensin-converting enzyme (ACE) inhibition. The formulations with GABA presented the most efficient ACE-inhibition, wherein beverages based on Brazil nut extract showed the highest results of ACE-inhibition (80%). This study evidenced that kefir fermentation enhanced plant-based beverages bioactivity, indicating their potential as functional beverages. The plant-based extracts and the bioactive compounds produced in this study characterize the beverages in an innovative way, due to the process, composition and simultaneous presence of probiotics and GABA, which had not been reported before.

Inulin or xylooligosaccharide addition to dulce de leche affects consumers' sensory experience and emotional response

The growing interest in reducing sugar and fat in processed foods has led to the use of fibers with prebiotic potential, such as inulin and xylooligosaccharide (XOS), as substitutes capable of enhancing nutritional value and sensory quality. Using an innovative approach with Free Just-About-Right (FREE JAR) to obtain Drivers of Liking, this study evaluated consumer perception (n = 129) regarding the impact of adding inulin and XOS to Dulce de Leche with or without fat reduction. The term "Too Greasy" was significant for the product made with whole milk; however, adding inulin and XOS mitigated this effect and promoted the sensation of JAR sweetness. The product made with skimmed milk and added XOS was associated with being "Too Thick." The sentiment map demonstrated that products made with whole milk, when compared to others, generated more positive opinions and evoked a more positive emotional response. In contrast, products made with skimmed milk were associated with negative opinions and emotional responses, possibly due to the fat reduction compromising the overall perception of the product. These results indicated that the addition of fibers has a positive impact on sensory perception, particularly in the modulation of texture and sweet taste. Therefore, this strategy can be cautiously considered in product reformulation. In the case of dulce de leche, fat played a fundamental role in the interaction between sensory attributes, and its reduction may require specific approaches to maintain product acceptance. The use of inulin and XOS is an alternative that can be explored to help preserve these sensory characteristics.

Physico-chemical and microbiological properties of water kefir produced from carob (Ceratonia siliqua L.) sherbet

In this study, sugar-free (A) and sugar-added (B) formulations of carob sherbet were fermented with water kefir grains. After 48 h of fermentation, the pH and total soluble solid content level (TSS) of A and B decreased, while the titratable acidity (TA) value increased. At the end of fermentation, Ave B formulations were stored at 4 °C for 28 days. Fermented sherbets' 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity decreased with storage. A had 75.3% DPPH radical scavenging activity on day 0th, whereas B had 77.0%. B had less total phenolic content (TPC) than fermented A on day 0. TPC values decreased significantly, notably on days 21st and 28th of storage. After fermentation, A had more gallic acid, hesperidin, p-coumaric acid, rosmarinic acid, and syringic acid than B. A had 2.21% sucrose before fermentation and 0.95% after. On 14th days of storage, potassium and calcium had the greatest mineral levels. Compared to A, B gave higher microbial count values (Lactobacillus sp., Lactococcus sp. total mesophilic aerobic bacteria, and yeast) in the microbiological analysis results at the end of fermentation and during storage.

Licuri Kernel (Syagrus coronata (Martius) Beccari): A Promising Matrix for the Development of Fermented Plant-Based Kefir Beverages

New licuri-based kefir beverages were obtained using water kefir grains as fermentation inoculum (1, 2.5, and 5%) under different fermentation times (24 and 48 h). Metagenomic sequencing of the kefir grains adapted to the aqueous licuri extract revealed Lactobacillus hilgardii and Brettanomyces bruxellensis to be predominant in this inoculum. The excellent adaptation of the kefir grains to the licuri extract raised the possibility of prebiotic action of these almonds. The beverages showed acidity values between 0.33 ± 0.00 and 0.88 ± 0.00 mg lactic acid/100 mL and pH between 3.52 ± 0.01 and 4.29 ± 0.04. The viability of lactic acid bacteria in the fermented beverages was equal to or greater than 108 CFU/mL, while yeasts were between 104 and 105 CFU/mL. There were significant differences (p < 0.05) in the proximate composition of the formulations, especially in the protein (1.37 ± 0.33-2.16 ± 0.84) and carbohydrate (5.86 ± 0.19-11.51 ± 1.26) contents. In addition, all the samples showed good stability in terms of acidity, pH, and viability for LAB and yeasts during 28 days of storage (4 °C). Overall, the beverages showed a dominant yellow-green color, non-Newtonian pseudoplastic behavior, and high mean scores in the sensory evaluation. This study provided evidence of the emerging potential of licuri in the plant-based beverage industry.

Study and characterization of a product based on a vegetable extract of quinoa fermented with water kefir grains

This work aimed to study and characterize a product based on vegetable extract of quinoa (WVEQ) fermented with water kefir grains. The effect of sucrose concentration (SC), inulin concentration (IC), and xanthan gum (XG) concentration were evaluated using a central composite design (CCD) 23. They were subsequently characterized regarding cellular growth of the grains, beverage yield, pH, soluble solids, carbon dioxide (CO2) production, lactic acid, and ethanol production. Therefore, for the final stage, two formulations (F1 and F8) of the CCD were chosen to be characterized in terms of proximate composition, microbiological composition of the kefir culture, analysis of organic compounds, sensory analysis, and enzymatic and microbiological characterization before and after simulation of in vitro gastrointestinal digestion. In the two chosen products, one can see that fermentation optimized the bioavailability of proteins due to the high proteolytic activity of the microorganisms in kefir and the increase in lipid content. In identifying microorganisms, there was a prevalence of Saccharomyces sp. yeasts. In the sensory analysis, the F8 formulation showed better results than the F1 formulation. In vitro, gastrointestinal digestion showed reduced lactic acid bacteria and yeast and increased acetic acid bacteria in the liquid phase for both formulations. In the enzymatic profile, there was a reduction in all enzymes analyzed for both formulations, except for amylase in F1, which went from 14.05 U/mL to 39.41 U/mL. Therefore, it is concluded that using WVEQ as a substrate for the product appears to be a viable alternative with nutritional and technological advantages for serving a specific market niche.

Flavor, physicochemical properties, and storage stability of P. lobata-coix seed fermented beverage produced by A. aegerita

Pueraria lobata and coix seeds have complementary nutritional profiles, and their nutritional value can be enhanced through biotransformation. Agrocybe aegerita (A. aegerita) is a highly nutritious mushroom with a rich enzyme content. This study investigated the flavor, physicochemical properties, and storage stability of P. lobata-coix seed fermented beverage (PCFB) by A. aegerita. Sixty volatile compounds were detected by headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry. Compared to unfermented PCFB, fermentation with A. aegerita enhanced its physicochemical properties, with the contents of essential amino acids, γ-Aminobutyric acid, and soluble proteins increasing from 16.81%, 2.64 mg/100 mL, and 49.40% to 21.06%, 4.20 mg/100 mL, and 53.08%, respectively. Two efficient shelf-life prediction models of PCFB were established with the Arrhenius model using pH and sensory evaluation as indexes. These findings demonstrate that PCFB is a novel, high-quality beverage and provide a foundation for potential industrial production of PCFB using A. aegerita.

Effect of oleaster (Elaeagnus angustifolia L.) flour addition combined with high-pressure homogenization on the acidification kinetics, physicochemical, functional, and rheological properties of kefir

In this study, the effects of peeled oleaster flour (OF) addition (0.5% and 1%) with high-pressure homogenization (HPH) at 100 MPa on acidification kinetics, physicochemical, functional, and rheological properties of kefir made from bovine whole milk were investigated. The fermentation kinetic parameters such as Vmax and T f decreased by 23.63% and 20%, respectively, with 1% OF and application of HPH. The combined use of two treatments had a positive effect on Lactobacillus and Lactococcus counts, reaching a maximum of 9.63 and 9.31 log cfu/mL, respectively. Also, total phenolic contents and antioxidant activity reached maximum values of 85.31 mg GAE/g and 17.22%, respectively. The ΔE value was more limited with HPH. The maximum firmness and water-holding capacity values were determined in the sample produced with 1% OF and application of HPH. Rheological analysis revealed that all kefirs exhibited shear thinning behavior, and the Ostwald-de-Waele (R 2 > .99) model was suitable to describe the rheological behavior of all kefir samples. The highest viscosity (0.049 Pa.s, at 50/s shear rate) and consistency index (1.115 Pa.sn) were observed in kefir with 1% OF and application of HPH. Kefir samples were characterized as weak gel behavior because storage modulus (G') was much greater than loss modulus (G") and the power-law model was used to characterize the viscoelasticity. The overall quality assessment indicated that the improvement of the fermentation process and the enhancement of textural and functional properties of kefir samples could be achieved with the addition of 1% OF and application of HPH.

Non-dairy prebiotics: Conceptual relevance with nutrigenomics and mechanistic understanding of the effects on human health

The increasing health awareness of consumers has made a shift towards vegan and non-dairy prebiotics counterparts. Non-dairy prebiotics when fortified with vegan products have interesting properties and widely found its applications in food industry. The chief vegan products that have prebiotics added include water-soluble plant-based extracts (fermented beverages, frozen desserts), cereals (bread, cookies), and fruits (juices & jelly, ready to eat fruits). The main prebiotic components utilized are inulin, oligofructose, polydextrose, fructooligosaccharides, and xylooligosaccharides. Prebiotics' formulations, type and food matrix affect food products, host health, and technological attributes. Prebiotics from non-dairy sources have a variety of physiological effects that help to prevent and treat chronic metabolic diseases. This review focuses on mechanistic insight on non-dairy prebiotics affecting human health, how nutrigenomics is related to prebiotics development, and role of gene-microbes' interactions. The review will provide industries and researchers with important information about prebiotics, mechanism of non-dairy prebiotics and microbe interaction as well as prebiotic based vegan products.

Effect of Agave Fructans on Changes in Chemistry, Morphology and Composition in the Biomass Growth of Milk Kefir Grains

Prebiotic effects have been attributed to agave fructans through bacterial and yeast fermentations, but there are few reports on their use as raw materials of a carbon source. Kefir milk is a fermented drink with lactic acid bacteria and yeast that coexist in a symbiotic association. During fermentation, these microorganisms mainly consume lactose and produce a polymeric matrix called kefiran, which is an exopolysaccharide composed mainly of water-soluble glucogalactan, suitable for the development of bio-degradable films. Using the biomass of microorganisms and proteins together can be a sustainable and innovative source of biopolymers. In this investigation, the effects of lactose-free milk as a culture medium and the addition of other carbon sources (dextrose, fructose, galactose, lactose, inulin and fructans) in concentrations of 2, 4 and 6% w/w, coupled with initial parameters such as temperature (20, 25 and 30 °C), % of starter inoculum (2, 5 and 10% w/w) was evaluated. The method of response surface analysis was performed to determine the optimum biomass production conditions at the start of the experiment. The response surface method showed that a 2% inoculum and a temperature of 25 °C were the best parameters for fermentation. The addition of 6% w/w agave fructans in the culture medium favored the growth of biomass (75.94%) with respect to the lactose-free culture medium. An increase in fat (3.76%), ash (5.57%) and protein (7.12%) content was observed when adding agave fructans. There was an important change in the diversity of microorganisms with an absence of lactose. These compounds have the potential to be used as a carbon source in a medium culture to increase kefir granule biomass. There was an important change in the diversity of microorganisms with an absence of lactose, where the applied image digital analysis led to the identification of the morphological changes in the kefir granules through modification of the profile of such microorganisms.

A Prospective Review of the Sensory Properties of Plant-Based Dairy and Meat Alternatives with a Focus on Texture

Consumers are interested in plant-based alternatives (PBAs) to dairy and meat products, and as such, the food industry is responding by developing a variety of different plant-based food items. For these products to be successful, their textural properties must be acceptable to consumers. These textural properties need to be thoroughly investigated using different sensory methodologies to ensure consumer satisfaction. This review paper aims to summarize the various textural properties of PBAs, as well as to discuss the sensory methodologies that can be used in future studies of PBAs. PBAs to meat have been formulated using a variety of production technologies, but these products still have textural properties that differ from animal-based products. Most dairy and meat alternatives attempt to mimic their conventional counterparts, yet sensory trials rarely compare the PBAs to their meat or dairy counterparts. While most studies rely on consumers to investigate the acceptability of their products' textural properties, future studies should include dynamic sensory methodologies, and attribute diagnostics questions to help product developers characterize the key sensory properties of their products. Studies should also indicate whether the product is meant to mimic a conventional product and should define the target consumer segment (ex. flexitarian, vegan) for the product. The importance of textural properties to PBAs is repeatedly mentioned in the literature and thus should be thoroughly investigated using robust sensory methodologies.

Biopolymer from Water Kefir as a Potential Clean-Label Ingredient for Health Applications: Evaluation of New Properties

The present work aimed to characterize the exopolysaccharide obtained from water kefir grains (EPSwk), a symbiotic association of probiotic microorganisms. New findings of the technological, mechanical, and biological properties of the sample were studied. The EPSwk polymer presented an Mw of 6.35 × 105 Da. The biopolymer also showed microcrystalline structure and characteristic thermal stability with maximum thermal degradation at 250 °C. The analysis of the monosaccharides of the EPSwk by gas chromatography demonstrated that the material is composed of glucose units (98 mol%). Additionally, EPSwk exhibited excellent emulsifying properties, film-forming ability, a low photodegradation rate (3.8%), and good mucoadhesive properties (adhesion Fmax of 1.065 N). EPSwk presented cytocompatibility and antibacterial activity against Escherichia coli and Staphylococcus aureus. The results of this study expand the potential application of the exopolysaccharide from water kefir as a potential clean-label raw material for pharmaceutical, biomedical, and cosmetic applications.

Isolation of Novel Yeast from Coconut (Cocos nucifera L.) Water and Phenotypic Examination as the Potential Parameters in Bioethanol Production

Yeast is a fermentation agent for producing bioethanol as an environmentally friendly alternative energy. Therefore, this study aims to find novel yeasts with the capability to persevere under acidic, high temperature, and high sugar content conditions, which are required in the bioethanol industry. The yeasts were isolated and identified from coconut (Cocos nucifera L.) water by a DNA sequencing method and phenotypic test. Yeast isolation has been completed with a serial dilution procedure and purification was conducted with HiPurA Genomic DNA Purification Spin Kits, which were analyzed by DNA Sequencing. The phenotypic test was carried out with thermotolerant (30 °C and 41 °C), high acidity (lactic acid), and sugar content (molasses 35 °brix) parameters in the media as the initial step of yeast ability screening. Based on the results, the three species of Candida tropicalis K5 (Candida tropicalis strain L2), K15 (Candida tropicalis strain MYA-3404), and K20 (Candida tropicalis strain Y277) obtained met the phenotypic standards. This showed that the yeasts have the potential to produce molasses-based bioethanol.

Designing Nutritious and Sustainable Biscuits Using Upcycled Fibre-Rich Ingredients Obtained by Hot Air - Microwave Drying of Orange by-Products

Circular use of resources implies developing mild processes to transform food by-products into value-added products, without using organic solvents or extensive washing and drying steps. Refined ingredients are commonly used in gluten-free bakery resulting in high levels of saturated fatty acids and sugars as well as a lack of essential nutrients like dietary fibres. The objective of this study was (i) to compare the nutritional composition and the water retention capacity (WRC) of an upcycled orange fibre dried by hot air combined with microwave (HAD+MW) and a commercial orange fibre obtained by different methods (COM), and (ii) to compare the nutritional, texture and sensory profile of gluten-free biscuits formulated with HAD+MW and with COM fibres. The total dietary fibre content (72.0 ± 3.0%) and WRC (21.1 ± 2.7 g_water/ g) of HAD+MW fibre did not differ from the nutritional composition of the control orange fibre (COM). However, for HAD+MW fibre, protein (+2.34 fold), fat (-4.75 fold), ash (-2.31 fold), sugars (-1.42 fold) and moisture content (+11.5 fold) was different from COM. Instrumental texture analysis showed that biscuits with HAD+MW fiber resulted in less hardness (26%) than those with COM fiber. However, this difference was not perceived by panellists (p > 0.05). Exterior colour, cereal, vanilla and citrus aroma-flavour, and granularity were slightly more intense in HAD+MW biscuits but still similar to the commercial control fiber. Thus, the HAD+MW drying method can be used for upcycling orange by-products, obtaining less refined and more nutritious and sustainable ingredients for fiber-enrichment of gluten-free biscuits.

Comparative Analysis of Fermentation Conditions on the Increase of Biomass and Morphology of Milk Kefir Grains

Kefir grains represent a symbiotic association group of yeasts, lactic acid bacteria and acetic acid bacteria within an exopolysaccharide and protein matrix known as kefiran. The mechanism of growth of a biomass of kefir after successive fermentations and optimal conditions is not well understood yet. Biomass growth kinetics were determined to evaluate the effects of temperatures (10 °C to 40 °C) and different substrates, such as monosaccharides (fructose, galactose, glucose), disaccharides (lactose, saccharose) and polysaccharides (Agave angustifolia fructans) at 2%, in reconstituted nonfat milk powder at 10% (w/v) and inoculated with 2% of milk kefir grain (105 CFU/g), after determining the pH kinetics. The best conditions of temperature and substrates were 20 °C and fructans and galactose. An increase in cells, grain sizes and a change in the morphology of the granules with the best substrates were observed using environmental scanning electron microscopy, confocal laser scanning microscopy and Image Digital Analysis (IDA). Kefir grains with agave fructans as their carbon source showed the higher fractal dimension (2.380), related to a greater co-aggregation ability of LAB and yeasts, and increase the formation of exopolysaccharides and the size of the kefir grains, which opens new application possibilities for the use of branched fructans as a substrate for the fermentation of milk kefir grains for the enhancement of cellular biomasses and exopolysaccharide production, as well as IDA as a characterization tool.

Water kefir: Factors affecting grain growth and health-promoting properties of the fermented beverage

Nowadays, the interest in the consumption of healthy foods has increased as well as the homemade preparation of artisanal fermented product. Water kefir is an ancient drink of uncertain origin, which has been passed down from generation to generation and is currently consumed practically all over the world. Considering the recent and extensive updates published on sugary kefir, this work aims to shed light on the scientific works that have been published so far in relation to this complex ecosystem. We focused our review evaluating the factors that affect the beverage microbial and chemical composition that are responsible for the health attribute of water kefir as well as the grain growth. The microbial ecosystem that constitutes the grains and the fermented consumed beverage can vary according to the fermentation conditions (time and temperature) and especially with the use of different substrates (source of sugars, additives as fruits and molasses). In this sense, the populations of microorganisms in the beverage as well as the metabolites that they produce varies and in consequence their health properties. Otherwise, the knowledge of the variables affecting grain growth are also discussed for its relevance in maintenance of the starter biomass as well as the use of dextran for technological application.

Water-soluble palm fruit extract: composition, biological properties, and molecular mechanisms for health and non-health applications

The oil palm (Elaeis guineensis) fruit is a source of vegetable oil and various phytonutrients. Phytochemical compounds present in palm oil include tocotrienols, carotenoids, phytosterols, squalene, coenzyme Q₁₀, and phospholipids. Being a fruit, the oil palm is also a rich source of water-soluble phytonutrients, including phenolic compounds. Extraction of phytonutrients from the oil palm vegetation liquor of palm oil milling results in a phenolic acid-rich fraction termed Water-Soluble Palm Fruit Extract (WSPFE). Pre-clinical in vitro, ex vivo, and in vivo studies carried out using various biological models have shown that WSPFE has beneficial bioactive properties, while clinical studies in healthy volunteers showed that it is safe for human consumption and confers antioxidant and anti-inflammatory effects. The composition, biological properties, and relevant molecular mechanisms of WSPFE discovered thus far are discussed in the present review, with a view to offer future research perspectives on WSPFE for health and non-health applications.