Black tea water kefir beverage : a thesis submitted in partial fulfilment of the requirement for the degree of Master of Food Technology, Massey University, Albany, New Zealand

Fermented foods and beverages play an important role in the human diet as they provide essential nutrients as well as contribute towards prevention of diseases. Lactic acid bacteria and yeasts are a major group of microorganisms associated with fermented products. Some of the microorganisms, known as probiotics, confer health properties to human health. Thus, many different types of fermented foods and beverages containing probiotics are produced around the world to support wellness and health. In recent years, there has been increased interest in the development of fermented functional plant-based foods and beverages due to a surge in scientific research of the products. Further, there is evidence that probiotic microorganisms can grow well in plant-based substrates. Water kefir is a sparkling fermented beverage with an acidic, sweet, slightly alcoholic taste, and a yeasty flavour. Water kefir fermentation can be achieved by the inoculation of water kefir grains as a starter culture into a solution containing sugar. Kefir grains consist of a symbiotic starter culture of lactic acid bacteria (LAB) and yeasts contained in a polysaccharide matrix. Microorganisms present in kefir grains are recognized as probiotics. The majority of previous studies have focused on the isolation and identification of water kefir cultures responsible for fermentation. There is, therefore, scanty information on the fermentation of plant-based water kefir beverages. The main objective of this study was to develop fermented black tea beverage using water kefir grains as a starter culture. Fermentation of black tea infusions as single and mixed substrate with carrot juice using water kefir grains were investigated. Microflora of water kefir grains used consisted of symbiotic starter culture of lactic acid bacteria (Lactococcus spp. and Lactobacillus spp.) and a yeast (Saccharomyces cerevisiae). The study was conducted in three main phases. The first phase investigated the effect of sucrose concentration (5% and 10%) and fermentation temperature (25°C and 30°C) in black tea water kefir fermentation for 72 h. Meanwhile, the effect of added carrot juice (5%, 10%, and 15%) on kefir beverage during secondary fermentation (24 h) at 25°C was investigated in the second phase. The stability of the final black tea water kefir beverage formulation during storage (4°C) for four weeks was investigated in phase three. Samples of black tea water kefir beverages were subjected to various analyses during fermentation and storage (4°C) for 4 weeks: titratable acidity, total soluble solids (°Brix), colour, viable cell counts of constituent starter culture, sensory evaluation, sugars, organic acids, antioxidants, and pH was also measured. Results showed that fermentation temperature, sugar concentration, and carrot juice concentration contributed to the physico-chemical and microbiological characteristic as well as sensory properties of the product. In phases one and two, pH and total soluble solids (°Brix) decreased, while titratable acidity and cell counts of LAB and yeasts increased during fermentation of the products. LAB and yeasts were able to grow in black tea and addition of carrot juice into the beverages slightly increased their growth. The best fermentation conditions based on physico-chemical and sensory properties were kefir beverage containing sugar (10%) and carrot juice (10%) fermented at 25°C for 96 h. In phase three, the growth and survival of Lactococcus spp. and Lactobacillus spp. were low during storage of the product (4°C) while Saccharomyces cerevisiae maintained high cell numbers (7.03±0.07 log cfu/ml) at the end of storage (28 days). Results showed the possibility to produce low sugar water kefir beverage containing 0.08±0.01% (w/v) sucrose, 1.55±0.04% (w/v) glucose, and 2.93±0.20% (w/v) fructose. The fermented kefir beverage also contained 0.202±0.02% (w/v) lactic acid, 0.114±0.03% (w/v) acetic acid and some antioxidants (gallic acid, ECG, EGC, EGCG, theobromine and caffeine) which may be beneficial to human health. There was significant difference (p<0.05) in the colour (L*, a*, b*) of the fermented beverages during storage (4°C). Black tea water kefir beverage containing 10% sugar and 10% carrot juice fermented at 25°C for 96 h was well-liked by consumer sensory panellists

Non-alcoholic beverages from fermented cereals with increased oligosaccharide content

The aim of this study is to develop a new technology for making traditional Lithuanian non-alcoholic beverage kvass from fermented cereals by extending the spectrum of raw materials (extruded rye) and applying new biotechnological resources (xylanolytic enzymes and lactic acid bacteria (LAB)) to improve its functional properties. Arabinoxylans in extruded rye were very efficiently hydrolysed into oligosaccharides by xylanolytic complex Ceremix Plus MG. Using Ceremix Plus MG and LAB fermentation, the yield of arabinoxylooligosaccharides and xylooligosaccharides in beverage was increased to 300 and 1100 mg/L, respectively. Beverages fermented by LAB had lower pH values and ethanol volume fraction compared to the yeast fermented beverage. The acceptability of the beverage fermented by Lactobacillus sakei was higher than of Pediococcus pentosaceus- or yeast-fermented beverages and similar to the acceptability of commercial kvass made from malt extract. The results showed that extruded rye, xylanolytic enzymes and LAB can be used for production of novel and safe high-value non-alcoholic beverages.Peer reviewe

Fermented beverages with health-promoting potential: Past and future perspectives

peer-reviewedFermentation is an ancient form of food preservation, which also improves the nutritional content of foods. In many regions of the world, fermented beverages have become known for their health-promoting attributes. In addition to harnessing traditional beverages for commercial use, there have recently been innovative efforts to develop non-dairy probiotic fermented beverages from a variety of substrates, including soy milk, whey, cereals and vegetable and fruit juices. On the basis of recent developments, it is anticipated that fermented beverages will continue to be a significant component within the functional food market

Saccharomyces cerevisiae in the production of fermented beverages

Alcoholic beverages are produced following the fermentation of sugars by yeasts, mainly (but not exclusively) strains of the species, Saccharomyces cerevisiae. The sugary starting materials may emanate from cereal starches (which require enzymatic pre‐hydrolysis) in the case of beers and whiskies, sucrose‐rich plants (molasses or sugar juice from sugarcane) in the case of rums, or from fruits (which do not require pre‐hydrolysis) in the case of wines and brandies. In the presence of sugars, together with other essential nutrients such as amino acids, minerals and vitamins, S. cerevisiae will conduct fermentative metabolism to ethanol and carbon dioxide (as the primary fermentation metabolites) as the cells strive to make energy and regenerate the coenzyme NAD+ under anaerobic conditions. Yeasts will also produce numerous secondary metabolites which act as important beverage flavour congeners, including higher alcohols, esters, carbonyls and sulphur compounds. These are very important in dictating the final flavour and aroma characteristics of beverages such as beer and wine, but also in distilled beverages such as whisky, rum and brandy. Therefore, yeasts are of vital importance in providing the alcohol content and the sensory profiles of beverages. This Introductory Chapter reviews, in general, the growth, physiology and metabolism of S. cerevisiae in alcoholic beverage fermentations

Plant-based beverages as good sources of free and glycosidic plant sterols

To address the ever-growing group of health-conscious consumers, more and more nutritional and health claims are being used on food products. Nevertheless, only very few food constituents, including plant sterols, have been appointed an approved health claim (European Commission and Food and Drugs Administration). Plant sterols are part of those limited lists of approved compounds for their cholesterol-lowering properties but have been praised for their anti-inflammatory and anti-carcinogenic properties as well. Despite this indisputable reputation, direct quantitative data is still lacking for naturally present (conjugated) plant sterols in beverages. This study aimed to fill this gap by applying a validated extraction and UPLC-MS/MS detection method to a diverse range of everyday plant-based beverages. B-sitosterol--D-glucoside (BSSG) showed to be by far the most abundant sterol in all beverages studied, with concentrations up to 60–90 mg per 100 mL in plant-based milk alternatives and fresh fruit juices. Ergosterol (provitamin D2) could be found in beers (0.8–6.1 g per 100 mL, from the yeast) and occasionally in juices (17–29 g per 100 mL). Overall, the results demonstrated that the concentrations of water-soluble sterol conjugates have been underestimated significantly and that specific plant-based beverages can be good, low-fat sources of these plant sterols

Development of a novel fermented pumpkin-based beverage inoculated with water kefir grains: a response surface methodology approach

Pumpkin (Cucurbita pepo) is well known for its health and nutritional benefits and is recommended for daily consumption. This is the first report on optimization and development of fermented pumpkin-based water kefir beverage. Optimum pumpkin puree and brown sugar concentrations were found at 22.28 and 9.07% w/v, respectively, were made into a pumpkin-based beverage and fermented with water kefir grains for 24 h at 32 �C. The optimized fermented pumpkin-based water kefir beverage was found to be non-alcoholic, achieved good overall acceptability and high Lactobacillus, acetic acid bacteria and yeast cell viability of approximately 1012, 109 and 109 CFU mL-1, respectively. Overall, the optimized product attained superb technological characteristics and has the potential for industrial exploitation as a refreshing water kefir drink

Munkoyo : des racines comme sources potentielles en enzymes amylolytiques et une boisson fermentée traditionnelle (synthèse bibliographique)

Munkoyo: roots as potential sources of amylolytic enzymes and a traditional fermented beverage. A review. Munkoyo is a fermented cereal-based beverage. The special feature of this beverage is the use of munkoyo roots as the source of amylolytic enzymes for manufacturing the beverage. This review summarizes the scientific knowledge on munkoyo. The following points are discussed: botanical description; distribution areas; propagation; chemical composition of roots; amylolytic enzymes in the roots and their properties; production process of the beverage; biochemical processes involved in the production of the beverage; and nutritional values and toxicity of the beverage. In order to highlight the value of munkoyo roots and to orientate research towards the optimization and/or industrialization of the production process, discussions are focused on a comparison of munkoyo with other fermented beverages and sources of amylolytic enzymes

Sequencing-Based Analysis of the Bacterial and Fungal Composition of Kefir Grains and Milks from Multiple Sources

peer-reviewedKefir is a fermented milk-based beverage to which a number of health-promoting properties have been attributed. The microbes responsible for the fermentation of milk to produce kefir consist of a complex association of bacteria and yeasts, bound within a polysaccharide matrix, known as the kefir grain. The consistency of this microbial population, and that present in the resultant beverage, has been the subject of a number of previous, almost exclusively culture-based, studies which have indicated differences depending on geographical location and culture conditions. However, culture-based identification studies are limited by virtue of only detecting species with the ability to grow on the specific medium used and thus culture-independent, molecular-based techniques offer the potential for a more comprehensive analysis of such communities. Here we describe a detailed investigation of the microbial population, both bacterial and fungal, of kefir, using high-throughput sequencing to analyse 25 kefir milks and associated grains sourced from 8 geographically distinct regions. This is the first occasion that this technology has been employed to investigate the fungal component of these populations or to reveal the microbial composition of such an extensive number of kefir grains or milks. As a result several genera and species not previously identified in kefir were revealed. Our analysis shows that the bacterial populations in kefir are dominated by 2 phyla, the Firmicutes and the Proteobacteria. It was also established that the fungal populations of kefir were dominated by the genera Kazachstania, Kluyveromyces and Naumovozyma, but that a variable sub-dominant population also exists.The Alimentary Pharmabiotic Centre is a research centre funded by Science Foundation Ireland (SFI), through the Irish Government’s National Development Plan. The authors and their work were supported by SFI CSET grant APC CSET 2 grant 07/CE/B1368

D 5.5.2. Report on near-market consumer testing of new improved products and substitutes in Africa. Project AFTER “African Food Tradition rEvisited by Research”

In this deliverable, the reengineered products relating to groups 1 to 3 are tested by consumers in Africa in order to test whether the acceptance meets consumer needs. The summaries are by group. These products were widely different and tested in differing cultures and situations. A common feature, however, is that all products are already commonly consumed by the communities and accepted, particularly with respect to the baseline products. Some products were found to be more acceptable (Gowe and Akpan in Benin, Kenkey in Ghana, Kong and Lanhouin in Senegal, Bissap and Baobab in Senegal), some of similar acceptance (Kitoza in Madagascar) and some were less acceptable (Kishk Sa'eedi in Egypt and Jaabi in Cameroon). Ways forward are discussed in all cases. Group 1: The reengineered group 1 products had mixed acceptance to consumers. Ones that were highly accepted were the reengineered Akpan which was highly accepted regardless of age, gender, socio- professional category and possessions (goods) and the majority (84.9%) expressed an interest for purchasing the reengineered Akpan and the reengineered gowe (n=100 consumers) in Benin, which was strongly accepted and more so than the traditional gowe. However, the reengineered Kenkey in Ghana while being comparable acceptance to the traditional white kenkey this would only meet a niche market. However, for the reengineered Kishk Sa'eedi, it was less acceptable and the difference was due to sour taste and spicy flavour. Group 2:The group 2 products had mixed acceptance among consumers. In the case of Kong in and Lanhouin in Senegal, the reengineered products had improved acceptance while for kitoza in Madagascar, there was no improvement in acceptance apart from those in terms of quality and safety. More specifically, Kong made using liquid smoke novel technique (RLK) had by far the highest acceptance and could easily be integrated as part of the Senegalese cuisine. This shows that there is a potential for RLK on the Senegalese market. Two types of reengineered Lanhouin types (Lanhouin dry powder, Lanhouin dry fillet) were greatly acceptable and the powdered form more than the fillet. In the case of Kitoza, consumer acceptance studies showed that there was no significant difference between all samples tested. Group 3: Group 3 reengineered products had mixed acceptance among consumers. Re-engineered bissap (hibiscus drinks) in Senegal were positively appreciated by consumers in Senegal and better accepted than the traditional commercial infusion used as baseline comparison. However, the new drinks were not perceivably different from the baseline drink to consumers concerning both the traditional character and the nutritional and healthy attributes. The reengineered baobab drinks were positively appreciated by consumers in Senegal and significantly better appreciated than the traditional commercial ones earlier tested. Jaabi (Ziziphus mauritiana). The result is the proposition of a reengineered Yaabande presenting fine texture well appreciated by consumers. However, particle size was critical and this needed to be lower than 125μm. Due to this limit, processors have adopted the manual production of flour of particle size 250μm>Ø>125μm, which is less tiresome, though it appears in second rank in the preference of consumers. The detailed methodology for each product is given for Groups I, II and III respectively. Common to all of the methodologies is the Ethical assessment and consent which is listed as follows: Ethical assessment and consent. The studies have been assessed and approved by the University of Greenwich Research Ethics Committee and the Ethics Committee at CIRAD. Consent was sought from sensory panellists and from adult consumers participating in this study. Enumerators informed participants about the study and explained that their participation was entirely voluntary, that they could stop the interview at any point and that the responses would be anonymous