Texture and water holding capacity of oat drinks fermented with lactic acid bacteria, bifidobacteria and Propionibacterium

ABSTRACTOats are among the most valued cereal commodities in the food market and are considered an exceptional grain. This study aimed focuses on assessing the impact of starter cultures, including lactic acid bacteria (i.e. Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus), Bifidobacterium animalis subsp. lactis Bb-12, and Propionibacterium freudenreichii subsp. shermanii PS-4, on selected quality parameters of yogurt-type fermented oat drinks. These drinks were produced by aqueous extraction of commercial oat flakes in drinking water. Acidification curves were determined during fermentation, and the oat drinks were subsequently stored at 6°C for 35 days. Throughout the study, acidity (measured by pH values), populations of lactic acid bacteria, bifidobacteria, and propionibacteria, as well as texture attributes (hardness and adhesiveness), water-holding capacity, and selected carbohydrate content were examined at the end of fermentation and every 7 days during storage. Results indicated that the addition of bifidobacteria and/or propionic acid bacteria in oat drink cultures expedited and improved the acidification process, resulting in a drink with a lower pH. Furthermore, the incorporation of propionic acid bacteria enhanced the water-holding capacity of the drink. Although the fermentation process had no significant impact on the texture of the oat drinks, the introduction of bifidobacteria reduced the adhesiveness of the final product. Carbohydrate content in the oat drinks diminished during fermentation, with sucrose experiencing the most substantial reduction. In conclusion, the study suggests that supplementing oat drink cultures with bifidobacteria and/or propionic acid bacteria proves to be an effective strategy for enhancing both the quality and shelf life of the final product

The Novel Strain of Gluconobacter oxydans H32 Isolated from Kombucha as a Proposition of a Starter Culture for Sour Ale Craft Beer Production

Acetic acid bacteria (AAB) has found applications in food technology, including beverages and vinegar. Generally, AAB shows several beneficial properties and has technological usefulness. Properly selected and tested strains of this group of bacteria may constitute a new and interesting solution among starter cultures for functional food. Therefore, the study aimed to develop a sour beer technology, based on the novel strain Gluconobacter oxydans H32. The microbiological, physical-chemical (HPLC method), and sensory (QDP method) quality were determined during 6 months of storage of dark and light beer samples. The AAB count at the beginning of storage was approximately 8 log CFU mL−1, and 6 log CFU mL−1 after 6 months of storage. As a result of the metabolic activity, acetic acid, gluconic acid, and ascorbic acid were detected in the samples. The light beer had a significantly better sensory quality, especially sample BPGL with the addition of G. oxydans H32 starter culture. It was found that it is possible to develop a functional beer with the novel strain Gluconobacter oxydans H32. These Sour Ale craft beers were not only a good source of H32 strain but also its pro-health metabolites

Acid contents and the effect of fermentation condition of Kombucha tea beverages on physicochemical, microbiological and sensory properties

Kombucha is a healthy beverage which is a final result of tea fermentation by adding a starter culture of the acetic acid bacteria and yeasts. The effect of fermentation conditions on physicochemical, microbiological and sensory properties of Kombucha tea beverages was evaluated with emphasis placed on determining sugars and organic acids content, including pro-health glucuronic acid. Fermentation process was conducted for 10 days at 20°C, 25°C and 30°C. The optimal conditions for the fermentation of Kombucha tea beverages were a temperature of 25°C and a period of 10 days which allowed to retrieve a product with good physicochemical, microbiological and sensory quality. The content of glucuronic acid increased during fermentation at all temperatures reaching the highest, on the 10th day of fermentation at 25°C. It was observed that all beverages were a good overall quality, whereas Kombucha fermented at 25°C was assessed as the highest.La fermentación de té, mediante la incorporación de cultivo iniciador de bacterias acidoacéticas y levaduras, produce la saludable bebida llamada Kombucha. Para efectos de este estudio, la valoración del efecto que las condiciones de fermentación tienen en las propiedades fisicoquímicas, microbiológicas y sensoriales de bebidas de té de Kombucha se centró en la determinación de azúcares y de la concentración de ácidos orgánicos, incluyendo el beneficioso ácido glucurónico. El proceso de fermentación se extendió 10 días a temperaturas de 20°C, 25°C y 30°C, constatándose que una temperatura de 25°C y un tiempo de 10 días constituyen condiciones óptimas para fermentar bebidas de té de Kombucha, ya que el producto resultante presentó buena calidad fisicoquímica, microbiológica y sensorial. A todas las temperaturas probadas, se comprobó que durante el proceso de fermentación aumentó la concentración de ácido glucurónico, alcanzando el contenido más elevado en el décimo día de fermentación a una temperatura de 25°C. Aunque se verificó que todas las bebidas presentaban buena calidad general, el té de Kombucha fermentado a 25°C mostró la valoración más alta

UPLC-PDA-Q/TOF-MS Profile of Polyphenolic Compounds of Liqueurs from Rose Petals (Rosa rugosa)

Polyphenolic compounds, as a secondary metabolite of plants, possess great nutritional and pharmacological potential. Herein, we applied the green analytical method to study the nutrient profile of Rosa rugosa petals and liqueurs manufactured from them. Using the fast and validated ultra performance liquid chromatography-photodiode detector-quadrupole/time of flight-mass spectrometry (UPLC-PDA-Q/TOF-MS) method, we confirm the presence of the following compounds: phenolic acids, flavonols, flavan-3-ols and hydrolisable tannins (gallotannins and ellagitannins). R. rugosa petals contains up to 2175.43 mg polyphenols per 100 g fresh weight, therein 1517.01 mg ellagitannins per 100 g fresh weight. Liqueurs, traditionally manufactured from said petals using a conventional extraction method (maceration), also contain polyphenols in significant amounts (from 72% to 96% corresponding to percentage of theoretical polyphenol content in the used petals), therein ellagitannins amount to 69.7% on average. We confirmed that traditional maceration, most common for the isolation of polyphenols, is still suitable for the food industry due to its using aqueous ethanol, a common bio-solvent, easily available in high purity and completely biodegradable. Therefore R. rugosa used as a food may be considered as an ellagitannin-rich plant of economic importance. Manufactured rose liqueurs were stable and kept all their properties during the whole period of aging

Profile of the Phenolic Compounds of Rosa rugosa

Rosa rugosa petals are a rich source of phenolic compounds, which determined their antioxidant properties. The aim of this study was to determine the polyphenolic composition of not processed petals of Rosa rugosa collected from the commodity crops and to determine the variability of the contained therein polyphenols between harvesting seasons. Twenty polyphenols were identified by UPLC-ESI-MS. The main fraction of polyphenols was ellagitannins, which are 69 to 74% of the total polyphenols of the petals. In the petals of Rosa rugosa, four anthocyanins have been identified: cyanidin 3,5-di-O-glucoside, peonidin 3-O-sophoroside, peonidin 3,5-di-O-glucoside, and peonidin 3-O-glucoside, of which the predominant peonidin 3,5-di-O-glucoside represented approx. 85% of all the determined anthocyanin compounds. It was found that the petals of Rosa rugosa are a valuable source of bioactive compounds and can be considered as a healthy valuable resource

Effect of Pullulan Coating on Postharvest Quality and Shelf-Life of Highbush Blueberry (Vaccinium corymbosum L.)

Fruits form an important part of a healthy human diet as they contain many ingredients with proven pro-health effects such as vitamins, phenolic compounds, organic acids, fiber, and minerals. The purpose of this work was to evaluate the effect of pullulan coating on the quality and shelf life of highbush blueberry during storage. General appearance, weight loss, dry matter, soluble solid content, reducing sugars, content of L-ascorbic acid, phenolic compounds (total phenolics, phenolics acids and anthocyanins) were determined in uncoated and coated blueberries fruits. The microbiological efficiency of pullulan coating was also evaluated. All parameters were monitored during storage at 4 °C and 16 °C by 28 and 14 days, respectively. The study showed that pullulan coating protects perishable food products especially susceptible to mechanical injury including fruits such as blueberries. Pullulan acts as a barrier that minimizes respiration rate, delaying deterioration and controlling microbial growth

Phenolic Contents and Antioxidant Activity of Extracts of Selected Fresh and Dried Herbal Materials

Total phenolic content (TPC) and phenolic profiles of extracts of the aerial parts of coriander (Coriandrum sativum L.), lovage (Levisticum officinale Koch.), and tarragon (Artemisia dracunculus L.), and leaves of Indian borage (Plectranthus amboinicus) have been investigated. The extracts were prepared using 70% (v/v) ethanol and fresh or air-dried herbal material. Besides phenolic composition, DPPH• and ABTS•+ scavenging activity, and ferric-reducing antioxidant power (FRAP) were determined. The extracts from dried herbal materials exhibited higher TPC and more potent antioxidant activity than those from fresh counterparts. The highest TPC (146.77 g GAE/kg extract) and antioxidant activity (0.491, 0.643, and 0.396 mol TE/kg extract in DPPH, ABTS, and FRAP assays, respectively) were detected for the extract from dried leaves of Indian borage, while the lowest values were determined for the extract from fresh aerial parts of coriander. Five phenolic acids (rosmarinic, chlorogenic, caffeic, ferulic, and neochlorogenic acids) and four flavonoids ((+)-catechin, rutin, hyperoside, and astragalin) were identified in the samples. Only caffeic acid was present in all extracts. Its content in the extracts of dried tarragon and Indian borage was lower than in those of the fresh material. A significant correlation was found between antioxidant activity and the content of phenolic acids. Rutin was found to be the major flavonoid in most extracts. Based on the present study results, the possibility of using the extracts obtained from both fresh and air-dried herbs as potential components for functional food formulation can be considered in the future

Antioxidant and Antibacterial Activity of Extracts from Selected Plant Material

Plants are a valuable source of biologically active molecules, mainly phenolic compounds. In the present study, the total phenolic content (TPC), DPPH· and ABTS+ scavenging activity as well as ferric reducing ability (FRAP) of aqueous ethanolic (70%) extracts of Cistus incanus L. and Asarum europaeum L. herb, Geum urbanum L. rhizome, Angelica archangelica L. root, white mulberry (Morus alba L.), lemon balm (Melisa officinalis L.), red raspberry (Rubus idaeus L.) and Betula pendula Roth. leaves were determined. In addition, the phenolic profiles of the studied plant extracts and antibacterial activity have been investigated. The extracts from C. incanus and G. urbanum demonstrated the highest TPC and antioxidant capacity, while the extracts from A. archangelica and white mulberry were characterized by the lowest values. A remarkable correlation was also found between the TPC and antioxidant activity of the examined extracts. HPLC analysis showed that the studied extracts were sources of both phenolic acids and flavonoids. More flavonoids than phenolic acids were identified in the extracts of C. incanus, M. alba, R. idaeus and B. pendula compared to the other extracts tested. Not all extracts showed a significant impact on the growth of the tested bacterial strains. Escherichia coli was the most sensitive strain to lemon balm extract (MIC, 0.125 mg/mL), whereas the strains of Acinetobacter baumannii and Bordetella bronchiseptica were sensitive to the G. urbanum extract (MIC, 0.125 mg/mL). Among Gram-positive bacteria, Enterococcus faecalis was the most sensitive to G. urbanum extract. In turn, Staphylococcus aureus and Staphylococcus epidermidis were sensitive to the extracts from C. incanus herb (MIC, 0.125 mg/mL), red raspberry (MIC, 0.125 mg/mL) and lemon balm leaves (MIC. 0.25 mg/mL). Based on the obtained results, the applicability of the studied plant extracts as additives to food and cosmetic products may be considered in the future