Metagenomics analysis of the polymeric and monomeric phenolic dynamic changes related to the indigenous bacteria of black tea spontaneous fermentation.

Spontaneous fermentation during black tea production involves several reactions, including the oxidation of phenolic compounds. This process has usually been studied without considering the potential involvement of indigenous tea microorganisms. This work utilised a metagenomic technique targeting bacterial 16S rRNA genes and evaluated the profile of phenolic compounds generated during the production of black tea. The resulting data were used to develop correlational and predictive functional analyses related to bacterial dynamics and the syntheses of various phenolic compounds. In particular, the genera Methylobacterium and Devosia were correlated with gallic acid and quercetin. Concurrently, the genera Sphingomonas, Chryseobacterium and Aureimonas were correlated with kaempferol, theaflavins, thearubigins and theabrownins. These results, supported by predicted functional analysis based on 16S rRNA genes associated with phenolic compounds, indicated that yfiH (polyphenol oxidase) and katG (catalase-peroxidase) are likely the dominant genes of the bacterial community involved in the black tea production process. This research suggests that bacteria could potentially contribute to the production process of black tea.

Strategies to Reduce Salt Content and Its Effect on Food Characteristics and Acceptance: A Review.

Sodium is a necessary nutrient for regulating extracellular fluid and transferring molecules around cell membranes with essential functions. However, the prevalence of some diseases is related to unnecessary sodium intake. As a result, a particular problem for the food industry remains a matter of sodium content in foods. It is considered that customer acceptance is associated with salt perception dynamics related to the evolution of food production. It is a significant challenge and technique to minimize the salt content of various foods and provide replacement products with substantial reductions in salt levels. This review summarizes salt reduction strategies related to health problems based on traditional review methodology, with practical and methodological screening performed to determine the appropriate reference sources. Various technological (salt replacement, food reformulation, size and structural modifications, alternative processing, and crossmodal odor interaction) and behavioral strategies (memory process, gradual salt reduction, and swap) are identified in this work, including a deeper understanding of the principles for reducing sodium content in foods and their effect on food characteristics and potential opportunities for the food industry. Thereby, the food industry needs to find the proper combination of each strategy's advantages and disadvantages to reduce salt consumption while maintaining product quality.

Characterization of Antimicrobial Composite Edible Film Formulated from Fermented Cheese Whey and Cassava Peel Starch.

Antimicrobial composite edible film can be a solution for environmentally friendly food packaging, which can be made from fermented cheese whey containing an antimicrobial agent and cassava peel waste that contains starch. The research aims to determine the formulation of fermented cheese whey and cassava peel waste starch, resulting in an antimicrobial composite edible film with the best physical, mechanical, and water vapour permeability (WVP) properties, as well as with high antimicrobial activity. This research was conducted using experimental methods with nine composite edible film formulation treatments with three replications. Three variations in the fermented cheese whey and cassava peel starch ratio (v/v) (1:3, 1:1, 3:1) were combined with variations in the addition of glycerol (20%, 33%, 45%) (w/w) in the production of the composite edible film. Then, the physical characteristics such as elongation at break, tensile strength, WVP, colour, and antimicrobial effect of its film-forming solution were observed. The results showed that 24 h of whey fermentation with Candida tropicalis resulted in an 18.50 mm inhibition zone towards Pseudomonas aeruginosa. The best characteristic of the film was obtained from the formulation of a whey:starch ratio of 1:3 and 33% glycerol, which resulted in a thickness value of 0.21 mm, elongation at break of 19.62%, tensile strength of 0.81 N/mm2, WVP of 3.41 × 10-10·g/m·s·Pa at a relative humidity (RH) of 100%-35%, and WVP of 9.84 × 10-10·g/m·s·Pa at a RH of 75%-35%, with an antimicrobial activity towards P. aeruginosa of 5.11 mm.