Modulation of gut microbiota by bioactive compounds for prevention and management of type 2 diabetes.

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by hyperglycemia and insulin resistance. Gut microbiota (GM) are specific groups of microbes colonized in the gastrointestinal (GI) tract. They profoundly influence health, disease protection, and associated with metabolic activities, and play a vital role in the production of functional metabolites from dietary substances. Dysbiosis of GM has been linked to the onset of T2DM and can be altered to attain eubiosis by intervention with various nutritional bioactive compounds such as polyphenols, prebiotics, and probiotics. This review presents an overview of the evidence and underlying mechanisms by which bioactive compounds modulate the GM for the prevention and management of T2DM.

Novel pathways in bacteriocin synthesis by lactic acid bacteria with special reference to ethnic fermented foods.

Ethnic fermented foods are known for their unique aroma, flavour, taste, texture and other sensory properties preferred by every ethnic community in this world culturally as parts of their eatables. Some beneficial microorganisms associated with fermented foods have several functional properties and health-promoting benefits. Bacteriocins are the secondary metabolites produced by the microorganisms mostly lactic acid bacteria present in the fermented foods which can act as lantibiotics against the pathogen bacteria. Several studies have been conducted regarding the isolation and characterization of potent strains as well as their association with different types of bacteriocins. Collective information regarding the gene organizations responsible for the potent effect of bacteriocins as lantibiotics, mode of action on pathogen bacterial cells is not yet available. This review focuses on the gene organizations, pathways include for bacteriocin and their mode of action for various classes of bacteriocins produced by lactic acid bacteria in some ethnic fermented foods.

Distribution and Diversity of Nisin Producing LAB in Fermented Food.

An attempt was made, to characterize natural antibiotics or lantibiotics from unconventional sources and its antibacterial spectrum against food borne pathogens and drug resistant bacteria. Six different traditional fermented foods i.e., fermented fish, fermented soybeans, Soibum (fermented bamboo shoots), milk, idly and dosa batter were used for the isolation of bacteriocin producing Lactic acid bacteria (LAB). Among all bacterial cultures isolated from the various sources, 129 cultures have found to produce antimicrobial compounds. Nisin specific reporter bacteria was utilized as biosensor to identify the Nisin like bacteriocin, where 10 cultures found to be positive Nisin producer. Identified Nisin like bacteriocin was partially concentrated by using ammonium sulphate followed by butanol extraction. Minimum inhibitory concentration (MIC) was analyzed against food borne pathogen and drug resistant bacteria. MIC of partially purified Nisin (pp-Nisin) of all the LAB isolates against food-borne pathogens are ranged between 0.5 and 92 µg/ml respected to various Gram-positive bacteria. Similarly, the drug resistant bacteria were also inhibited by pp-Nisin (MIC ranged between 15 and 175 µg/ml). All samples of ppnisin exhibited auto induction ability. Taxonomic identification of the nisin producers was done by whole genome sequencing which reveals that cultures belongs to Lactococcus lactis ssp. lactis. Also it was found that Lactococcus lactis ssp. lactis C2d and Lactococcus lactis ssp. lactis SP2C4 harbor nisA gene and Lactococcus lactis ssp. lactis FS2 (L. lactis FS2) harbor nisQ gene. The finding of this study highlights the first case of L. lactis FS2 isolated from fermented fish harbor nisQ gene. Antibacterial activity of pp-Nisin against drug resistant LAB is also reported.

Influence of Pre-Drying Treatments on Physico-Chemical and Phytochemical Potential of Dried mahua Flowers.

Mahua (Madhuca longifolia) flowers are boon for the local tribes of India and have been successfully utilized traditionally for the value addition, and are very prone for microbial spoilage. Local folks utilized malpractices of drying which deteriorates the quality attributes of the mahua flowers and ultimately fails to fetch a good price in the market. Present investigation was led to consider the impact of different pre-treatments i.e., blanching time; and dip of potassium meta-bisulfite (KMS) and citric acid (CA) on the physico-chemical and phytochemical potential of dried mahua flowers using response surface methodology (RSM). Maximum physico-chemical and phytochemicals attributes were observed under optimum conditions i.e., a blanching of 4.1 min followed by dipping in solution having 1285 ppm KMS and 0.77% citric acid. Qualitative analysis through Fourier transform infrared spectroscopy (FTIR) supported the findings. Sugar and phytochemical profiling by high performance liquid chromatography (HPLC) proved the significant effect of each variable. No specific cluster formation was observed during cluster analysis of whole data indicating the significant and equal effect of all variable on the quality of dried mahua flowers. The optimized conditions will definitely help the local processors as well as the industrialist to maintain the quality attributes of the dried mahua.

Microbial maceration: a sustainable approach for phytochemical extraction.

A rapid change in the lifestyle has witnessed poor health with the increased incidences of numerous diseases in the recent years, and ultimately increasing the demand of nutritious foods containing phytochemicals. A wide range of phytochemicals (secondary metabolites) is being synthesized in plants, which influence the human health upon consumption as dietary component. Recently, a number of the technologies (conventional and non-conventional methods) have been standardized by the different researchers for the extraction of these phytochemicals depending upon the raw material. However, selection of extraction method for commercial use depends upon various factors such as extraction efficiency, time required, and cost of operation. Considering these factors, microbial maceration is one of the viable approaches which is easy to handle, cost-effective, energy efficient, less hazardous and having high extraction rate. Recently, researchers have utilized this technique for the maceration of different plant-based substrates (such as legumes, cereals, pulses, fruits and vegetables) and their respective wastes for the efficient extraction of numerous phytochemicals with increased efficiency. However, scale up studies and analysis of toxic compounds produced by microbes are still a lacking field and need to be explored further by the researchers and industrialists to bring it into reality. Therefore, the present review aims to document the recent findings related to microbial maceration in a crisp way to provide the complete information to the readers.