Polyphenols, L-Ascorbic Acid, and Antioxidant Activity in Wines from Rose Fruits (Rosa rugosa)

Changes in the antioxidant and anti-inflammatory activities of Rosa rugosa 'Mohong' during fermentation

Fermented rose petals are a traditional delicacy of the Dali Bai community in Yunnan, China. Fermentation enhances the quality and nutritional value of roses, as well as their efficacy, by increasing the levels of phenolic compounds. This study aimed to investigate the significant variations in four active compounds throughout the traditional fermentation process. Four compounds in Rosa rugosa 'Mohong' were examined, and significant variations among polyphenols and antioxidant and anti-inflammatory activities were observed. These variations were studied during fermentation by Saccharomyces rouxii at varying temperatures and durations. Moreover, the results showed that gallic acid and syringic acid content significantly increased (P < 0.05) with a rise in temperature from 20°C-35 °C during fermentation. Simultaneously, rutin and quercetin levels significantly decreased (P < 0.05) at all four temperatures throughout the five periods. The antioxidant and anti-inflammatory activities of fermented R. rugosa 'Mohong' methanol extracts were dose-dependent. Our results provide valuable insights into optimizing the processing scale and quality control of fermented rose products.

Phyllanthi Fructus: A modal medicinal and food homologous item in quality evaluation

Phyllanthi Fructus is a highly unique medicine and food homologous item, which exhibits distinctive flavor, notable nutritional value, and abundant pharmacological activity. It has enormous potential in the creation of health products and pharmaceuticals. However, due to the unique laws of quality formation and transfer of Phyllanthi Fructus, its appearance, shape, chemical compositions, nutrients, and sensory flavors are frequently greatly influenced by botanical resources, the processing and storage conditions. As a result, the current quality evaluation model is difficult to meet the needs of Phyllanthi Fructus as a medicine and food homologous item in the development of diversified products. This paper constructs the hierarchical utilization mode of Phyllanthi Fructus based on its unique quality formation and transmission laws, explores the quality evaluation model for food-oriented use and medicinal-oriented use, respectively, and systematically describes the quality evaluation idea under diversified application scenarios. This paper aims to serve as a reference for the construction of a quality evaluation model suitable for the medicine and food homologous item of Phyllanthi Fructus.

Efficient Production of 2,5-Diketo-D-gluconic Acid by Reducing Browning Levels During Gluconobacter oxydans ATCC 9937 Fermentation

D-Glucose directly generates 2-keto-L-gulonic acid (2-KLG, precursor of vitamin C) through the 2,5-diketo-D-gluconic acid (2,5-DKG) pathway. 2,5-DKG is the main rate-limiting factor of the reaction, and there are few relevant studies on it. In this study, a more accurate quantitative method of 2,5-DKG was developed and used to screen G. oxydans ATCC9937 as the chassis strain for the production of 2,5-DKG. Combining the metabolite profile analysis and knockout and overexpression of production strain, the non-enzymatic browning of 2,5-DKG was identified as the main factor leading to low yield of the target compound. By optimizing the fermentation process, the fermentation time was reduced to 48 h, and 2,5-DKG production peaked at 50.9 g/L, which was 139.02% higher than in the control group. Effectively eliminating browning and reducing the degradation of 2,5-DKG will help increase the conversion of 2,5-DKG to 2-KLG, and finally, establish a one-step D-glucose to 2-KLG fermentation pathway.

Exploring Use of the Metschnikowia pulcherrima Clade to Improve Properties of Fruit Wines

Mixed fermentation using Saccharomyces cerevisiae and non-Saccharomyces yeasts as starter cultures is well known to improve the complexity of wines and accentuate their characteristics. This study examines the use of controlled mixed fermentations with the Metschnikowia pulcherrima clade, Saccharomyces cerevisiae Tokay, and non-conventional yeasts: Wickerhamomyces anomalus and Dekkera bruxellensis. We investigated the assimilation profiles, enzyme fingerprinting, and metabolic profiles of yeast species, both individually and in mixed systems. The chemical complexity of apple wines was improved using the M. pulcherrima clade as co-starters. M. pulcherrima with S. cerevisiae produced a wine with a lower ethanol content, similar glycerol level, and a higher level of volatilome. However, inoculation with the Dekkera and Wickerhamomyces strains may slightly reduce this effect. The final beneficial effect of co-fermentation with M. pulcherrima may also depend on the type of fruit must.

Antagonistic Activity of Lactic Acid Bacteria and Rosa rugosa Thunb. Pseudo-Fruit Extracts against Staphylococcus spp. Strains

Staphylococcus bacteria are ubiquitous microorganisms. They occur in practically all environments. They also show the ability to colonize the skin and mucous membranes of humans and animals. The current trend is to look for new natural factors (e.g., plant extracts rich in polyphenols) limiting the growth of undesirable bacteria in food and cosmetics or use as an adjunct in antibiotic therapy. The aim of this study was to evaluate the effect of extracts from Rosa rugosa Thunb. on the antagonistic properties of selected lactic acid bacteria strains in relation to Staphylococcus spp. isolates. The biological material consisted of seven strains of lactic acid bacteria (LAB) and seven strains of bacteria of the Staphylococcus genus. The anti-staphylococcal properties of the Rosa rugosa Thunb. pomace extracts (the tested extracts were characterized by a high content of polyphenols, namely 8–34 g/100 g DM/dm) were tested using the well method. The conducted research showed that the pomace extracts of the pseudo-fruit (Rosa rugosa Thunb.) had the ability to inhibit the growth of Staphylococcus spp. bacteria. The minimum concentration of polyphenols inhibiting the growth of staphylococci was in the range of 0.156–0.625 mg/mL. The conducted research showed that combined lactic acid bacteria and extracts from the pomace from the pseudo-fruit Rosa rugosa Thunb. (LR systems) may be factors limiting the growth of Staphylococcus spp. bacteria. As a result of the research, two-component antagonist systems consisting of LAB cultures and extracts from Rosa rugosa Thunb. pomace were developed, which effectively limited the growth of the test strains of Staphylococcus spp. In 41% of all tested cases, the zone of inhibition of growth of bacteria of the genus Staphylococcus spp. after the use of two-component antagonist systems was higher than that as a result of the control culture (without the addition of extracts).