Advances in Kombucha Tea Fermentation: A Review

Kombucha is a carbonated, slightly acidic beverage traditionally produced by the fermentation of sweetened tea by a symbiotic culture of bacteria and yeast (SCOBY). The microbial community of kombucha is a complex one, whose dynamics are still not fully understood; however, the emergence of culture-independent techniques has allowed a more comprehensive insight into kombucha microbiota. In recent times, advancements have been made towards the optimisation of the fermentation process, including the use of alternative substrates, defined starter cultures and the modification of fermentation parameters, with the aim of producing an innovative beverage that is improved in terms of its physiochemical, sensory and bioactive properties. The global kombucha market is rapidly increasing, with the rising popularity of the tea attributed in part to its purported health benefits, despite the lack of research in human subjects to substantiate such claims. Accordingly, the incidence of kombucha home-brewing has increased, meaning there is a requirement for individuals to recognise the potential hazards associated with fermentation and the relevant preventative measures to be undertaken to ensure the safe preparation of kombucha. The aim of this review is to provide an update regarding the current knowledge of kombucha production, microbiology, safety and marketing.

The Influence of Low-Temperature Disintegration on the Co-Fermentation Process of Distillation Residue and Waste-Activated Sludge

Innovative low-temperature disintegration (process temperature 55 °C and oxygen concentration 0.2 mg/dm3) can be an economically rational technology to intensifying energy production from renewable sources. The proposed process can achieve a degree of disintegration—under optimal conditions—of about 50%, which is excellent when compared with other methods of feed pre-treatment. The low-temperature disintegration of distillation residue and waste-activated sludge before the co-fermentation process increased biogas production by 30% and methane production by 65% (over a 26 d duration). The obtained results confirm that the low-temperature disintegration method can be effectively used to pre-prepare this type of feed. At the same time, it was discovered that the Gompertz model can be used to mathematically describe the biogas accumulation curves in the methane co-fermentation processes of the tested feeds (the correlation coefficients were higher than 0.98).

The use of a mixture of vegetable powders in the production of bakery products

В последние годы все большее внимание уделяется разработке продукции, обогащенной растительными компонентами. Целью данной работы являлось исследование влияния смесей из порошков растительного происхождения на свойства теста и качество готовых изделий (булочной мелочи). В рецептуру изделий добавляли растительные смеси: № 1 - порошок облепихи, жимолости, мелкоплодных яблок и порошок из жмыха тыквы, № 2 - порошок облепихи и мелкоплодных яблок в количестве 10, 15 и 20 % от массы муки по сухому веществу. Смеси составляли из компонентов, взятых в равных количествах. Сравнительная оценка пищевой ценности смесей показала, что в смеси № 1 выше количество пищевых волокон, кальция и фосфора относительно смеси № 2. В смеси № 2 преобладает количество белков, жиров, органических кислот, калия, натрия, марганца и железа. По содержанию витаминов преимущество на стороне смеси № 2, за исключением витаминов В и В. Установили повышение кислотности теста с внесением растительных смесей, что указывает на интенсификацию процесса брожения. Исследование качества готовых изделий показало, что при соответствии физико-химических показателей требованиям технической документации, при дозировках смесей выше 10 % отмечали значительное потемнение цвета изделий, появление растительного привкуса, а в изделиях с добавлением смеси №1 неприятное послевкусие. Наиболее рациональной для производства хлебобулочных изделий повышенной пищевой ценности для здорового питания признана рецептура с использованием растительной смеси № 2 из порошков облепихи и мелкоплодных яблок в количестве 10 % к массе муки. In recent years, more and more attention has been paid to the development of products enriched with plant components. The purpose of this work was to study the effect of mixtures of powders of vegetable origin on the properties of dough and the quality of finished products (bakery trifles). Vegetable mixtures were added to the recipe of the products: No. 1 - sea buckthorn powder, honeysuckle, small-fruited apples and pumpkin cake powder; No. 2 - sea buckthorn powder and small-fruited apples, in the amount of 10, 15 and 20 % of the flour weight by dry matter. The mixtures were made up of components taken in equal quantities. A comparative assessment of the nutritional value of the mixtures showed that the amount of dietary fiber, calcium and phosphorus in mixture No. 1 is higher, relative to mixture No. 2. The mixture No. 2 is dominated by the amount of proteins, fats, organic acids, potassium, sodium, manganese and iron. In terms of vitamin content, the advantage is on the side of mixture No. 2, with the exception of vitamins B and B. An increase in the acidity of the dough was established, with the introduction of vegetable mixtures, which indicates an intensification of the fermentation process. The study of the quality of finished products showed that when the physico-chemical parameters meet the requirements of technical documentation, at dosages of mixtures above 10%, a significant darkening of the color of the products, the appearance of a vegetable taste, and in products with the addition of mixture No. 1, an unpleasant aftertaste was noted. The most rational recipe for the production of bakery products of increased nutritional value for a healthy diet is recognized, using a vegetable mixture No. 2 of sea buckthorn powders and small-fruited apples in an amount of 10 % by weight of flour.

Simulation Platform for Fault Diagnosis

The previous chapters have described the mathematical principles and algorithms of multivariate statistical methods, as well as the monitoring processes when used for fault diagnosis. In order to validate the effectiveness of data-driven multivariate statistical analysis methods in the field of fault diagnosis, it is necessary to conduct the corresponding fault monitoring experiments. Therefore this chapter introduces two kinds of simulation platform, Tennessee Eastman (TE) process simulation system and fed-batch Penicillin Fermentation Process simulation system. They are widely used as test platforms for the process monitoring, fault classification, and identification of industrial process. The related experiments based on PCA, CCA, PLS, and FDA are completed on the TE simulation platforms.

Green environment: Effects of acetate buffer on cellulose production by Acetobacter xylinum 0416 in fermented static cultivation

Bacterial cellulose (BC) white leathery pellicle produced from fermentation process of Acetobacter xylinum has many advantages such as high-water holding capacity, high porosity and high purity compared to plant cellulose. However, one of the BC application problems in industry is its low bio-cellulose productivity. The significant decrease of BC production can be effected by the reduction of pH culture due to production of by-product, gluconic acid during the static fermentation process. Therefore, the production of BC pellicle would be improved efficiently by controlling the pH of BC static cultivation. Bio-cellulose dry weight was at the greatest in acetates of 5.66 g/L while the dry weight derived from BC is 2.72 and 2.56 g/L in Control and Hestrin and Schramm (HS). The acetate buffered medium can be completed in a static fermentation method which can improve BC film production effectively.

Study of C/N ratio of organic materials and its application in the production of natural fertilizer (bokashi)

Bokashi is an organic fertilizer made from organic materials through fermentation process. A high quality bokashi should have C/N ratio between 10-20, which normally produced from a mix raw organic material with has C/N ratio of 30. However, many studies have shown a composition of raw organic material without a calculation of C/N ratio. Therefore, the objectives of this study were to gather the initial C/N ratio of various raw material from previous published studies, calculate the C/N ratio, and examine the descriptive characteristic (colour, aroma, and texture) of bokashi made from three selected C/N ratios of raw material (30, 70, and 110) and various length of fermentation (10, 17, and 24 days). This research combined literature reviews and laboratory experimental. For laboratory experimental, Complete Randomise Design (CRD) was applied. The result showed that all bokashi produced from raw material mixture with the C/N ratio up to 110 was still acceptable to be directly applied as a fertilizer. Bokashi produced with longer fermentation time had better texture but lower aroma and colour quality.