Phenotypic identification and technological attributes of native lactic acid bacteria present in fermented bamboo shoot products from North-East India

The influence of non-starch polysaccharides on the formation mechanism of wheat dough

The study examined the effects of oat β-glucan (OβG), chitosan (CTS), araboxylan (AX), and fructosan (FOS) on wheat dough formation. Adding 0-7 % OβG, AX, and FOS increased SS content, enhancing gluten stability. D-AX and D-FOS showed higher β-sheet structures, higher air retention and gluten network, smaller pores and denser structures, higher elastic and viscosity moduli. Excessive OβG and CTS could reduce the dough stability, and β-turn and β-sheet ratios, respectively. Therefore, B-7AX and B-7FOS exhibited lower hardness indices during storage, leading to a smoother appearance and more orderly gas chamber distribution. The study provides a theoretical foundation for using non-starch polysaccharides in flour-based products.

Pan-genome analysis and molecular docking unveil the biocontrol potential of Bacillus velezensis VB7 against Phytophthora infestans

Management of late blight of potato incited by Phytophthora infestans remains a major challenge. Coevolution of pathogen with resistant strains and the rise of fungicide resistance have made it more challenging to prevent the spread of P. infestans. Here, the anti-oomycete potential of Bacillus velezensis VB7 against P. infestans through pan-genome analysis and molecular docking were explored. The Biocontrol potential of VB7 against P. infestans was assessed using a confrontational assay. The biomolecules from the inhibition zone were identified and subjected to in silico analysis against P. infestans target proteins. Nucleotide sequences for 54 B. velezensis strains from different geographical locations were used for pan-genome analysis. The confrontational assay revealed the anti-oomycetes potential of VB7 against P. infestans. Molecular docking confirmed that the penicillamine disulfide had the maximum binding energy with eight effector proteins of P. infestans. Besides, scanning electron microscopic observations of P. infestans interaction with VB7 revealed structural changes in hypha and sporangia. Pan-genome analysis between 54 strains of B. velezensis confirmed that the core genome had 2226 genes, and it has an open pan-genome. The present study confirmed the anti-oomycete potential of B. velezensis VB7 against P. infestans and paved the way to explore the genetic potential of VB7.

"Ethno-microbiology" of ethnic Indian fermented foods and alcoholic beverages

The concept of "ethno-microbiology" is to understand the indigenous knowledge of the Indian people for production of culturally and organoleptically acceptable fermented foods by natural fermentation. About 1000 types of common, uncommon, rare, exotic and artisan fermented foods and beverages are prepared and consumed in different geographical regions by multi-ethnic communities in India. Indian fermented foods are mostly acidic and some are alkaline, along with various types of alcoholic beverages. A colossal diversity of microorganisms comprising bacteria mostly belongs to phylum Firmicutes, filamentous moulds and enzyme- and alcohol-producing yeasts under phyla Ascomycota and Mucoromycota, and few bacteriophages and archaea have been reported from Indian fermented foods. Some microorganisms associated with fermented foods have functionalities and health promoting benefits. "Ethno-microbiology" of ethnic Indian people has exhibited the proper utilisation of substrates either singly or in combination such as fermented cereal-legume mixture (idli, dosa and dhokla) in South and West India, sticky fermented soybean food (kinema and related foods), fermented perishable leafy vegetable (gundruk and related foods), fermented bamboo shoots (soibum and related foods) and fermented fish (ngari and others) in North East India, and fermented meat and sausage-like products in the Indian Himalayas, fermented coconut beverage (toddy) in coastal regions, and various types of naturally fermented milk products (dahi and related products) in different regions of India. This review has also highlighted the "ethno-microbiology" knowledge of the people involving the consortia of essential microorganisms in traditionally prepared amylolytic starters for production of cereal-based alcoholic beverages. The novelty of this review is the interpretation of ethno-microbiological knowledge innovated by ethnic Indian people on the use of beneficial microorganisms for food fermentation to obtain the desired fermented food products for consumption.

Metagenomic Analysis of Bacterial Diversity in Traditional Fermented Foods Reveals Food-Specific Dominance of Specific Bacterial Taxa

Traditional fermented foods have been recognized by various communities to be good for health since ancient times. There is a provincial legacy of traditional fermented foods among the ethnic population of North-East India. Fermented bamboo shoots (local name: Tuaither), soybeans (Bekang), and pork fat (Sa-um) are famous in the Mizoram state and represent a primary portion of the daily diet. These foods are prepared using methods based on cultural traditions inherited from previous generations, and prepared using a relatively uncontrolled fermentation process. Analysis of the bacterial diversity in these foods can provide important information regarding the flavor and texture of the final products of fermentation. Unfortunately, studies on the microbial composition and health benefits of such traditional fermented foods have rarely been documented. Therefore, the present study aims to highlight this bacterial diversity, along with the proximate composition of different traditional fermented foods (Tuaither, Bekang and Sa-um) primarily consumed in Mizoram state, India. Samples were collected on three different days of fermentation (3rd, 5th and 7th day), and bacterial diversity analysis was performed using the V3-V4 variable region of 16S rRNA gene with Illumina sequencing. Results revealed differences in the bacterial composition of dominant group members among all of the three food types. Firmicutes (82.72–94.00%), followed by Proteobacteria (4.67–15.01%), were found to dominate to varying degrees in all three of the fermented foods. However, at genus level high variation was observed in bacterial composition among these three different types of fermented foods. Lactobacillus (91.64–77.16%), Staphylococcus (52.00–17.90%), and Clostridium (72.48–55.40%) exhibited the highest relative abundances in the Tuaither, Bekang and Sa-um foods, respectively, in descending order from the 3rd to 7th day of fermentation. A few of the bacterial genera such as Lactobacilli were positively correlated with fermented bamboo shoot samples, and Staphylococcus was positively correlated with protein, carbohydrate and crude fiber content in soybean samples. In general, Tuaither, Bekang and Sa-um exhibited distinct differences in bacterial composition. This variation may be due to differences in the raw materials and/or methods used in the preparation of the different fermented food products. This is the first study to describe the bacterial composition of these traditional fermented foods using high-throughput sequencing techniques, and could help to drive research attention to comprehensive studies on improving understanding of the role of microbial communities in the preparation of traditional foods and their health benefits.

Selection of Lactic Acid Bacteria Isolated from Fresh Fruits and Vegetables Based on Their Antimicrobial and Enzymatic Activities

Lactic acid bacteria (LAB) are an important source of bioactive metabolites and enzymes. LAB isolates from fresh vegetable sources were evaluated to determine their antimicrobial, enzymatic, and adhesion activities. A saline solution from the rinse of each sample was inoculated in De Man, Rogosa and Sharpe Agar (MRS Agar) for isolates recovery. Antimicrobial activity of cell-free supernatants from presumptive LAB isolates was evaluated by microtitration against Gram-positive, Gram-negative, LAB, mold, and yeast strains. Protease, lipase, amylase, citrate metabolism and adhesion activities were also evaluated. Data were grouped using cluster analysis, with 85% of similarity. A total of 76 LAB isolates were recovered, and 13 clusters were formed based on growth inhibition of the tested microorganisms. One cluster had antimicrobial activity against Gram-positive bacteria, molds and yeasts. Several LAB strains, PIM4, ELO8, PIM5 and CAL14 strongly inhibited the growth of L. monocytogenes and JAV15 and TOV9 strongly inhibited the growth of F. oxysporum. Based on enzymatic activities, 5 clusters were formed. Seven isolates hydrolyzed starch, 46 proteins, 14 lipids, and 36 metabolized citrate. LAB isolates with the best activities were molecularly identified as Leuconostoc mesenteroides, Enterococcus mundtii and Enterococcus faecium. Overall, LAB isolated from vegetables showed potential technological applications and should be further evaluated.

Nondairy ice cream based on fermented yam (Dioscorea sp.)

BACKGROUND

The demand for industrialized foods that contribute to health and well-being has characterized the new generation of consumers. Yam (Dioscorea sp.) is a nutritious food; however, it is not used very much in industrial food processes. The objective of this study was to develop and to characterize a truly dairy-free low-fat ice cream prepared from unfermented and fermented with yam dough.

RESULTS

The fermentation was conducted by Leuconostoc lactic CCMA 0415 remained viable (107 CFU/g) during 90 days of storage. The fermentation process reduced the starch concentration from 26.82% to 22.35% and the protein concentration from 4.68% to 3.99% and increased the concentration of some minerals (K, S, Cu, Mn, Zn, and Fe). The total phenolic contents for fermented and unfermented ice creams were 51 and 54 mg, respectively. The radical scavenging activity were 18% and 10% with the 1,1-diphenyl-2-picrylhydrazyl method and 44% and 26% with the 2,2'-azino-bis (3 ethylbenzo-thiazoline-6-sulfonic acid) method for the unfermented and fermented samples, respectively. The fermented and unfermented ice creams were both characterized as non-Newtonian fluids exhibiting pseudoplastic behaviors.

CONCLUSIONS

These results indicated that yam is a suitable substitute for milk, thus making it an option to produce edible lactose-free ice cream with low fat.

Effects of Bamboo Shoot Dietary Fiber on Mechanical Properties, Moisture Distribution, and Microstructure of Frozen Dough

In this paper, the effects of Bamboo shoot dietary fiber (BSDF) on the mechanical properties, moisture distribution, and microstructure of frozen dough were investigated. The state and distribution of water in frozen dough was determined by differential scanning calorimetry (DSC) and low-field nuclear magnetic resonance (LNMR) spectroscopy. The microstructure of frozen dough was studied. The structure of the gluten protein network found in wheat flour dough was studied by scanning electron microscopy (SEM). The result showed that the BSDF could significantly improve the viscoelasticity and extensibility of frozen dough after thawing in a dose-dependent manner. It was significantly improved with the increase in the addition amount of BSDF (P<0.05). DSC analysis showed that the freezable water content and thermal stability of frozen dough were increased after the addition of BSDF. LNMR analysis showed that the appropriate (<0.1%) addition amount of BSDF could significantly (P<0.05) decline the contents of bound water. Meanwhile, the loose bound water and free water were raised significantly (P<0.05) after the addition of BSDF. Moreover, the addition of BSDF induces arrangement of starch granule and gluten network in frozen dough. BSDF can be used as a novel quality improver of frozen dough.

Probiotic attributes of indigenous Lactobacillus spp. isolated from traditional fermented foods and beverages of north-western Himalayas using in vitro screening and principal component analysis

The present research was designed to explore indigenous probiotic Lactic acid bacteria from traditional fermented foods and beverages of North-western Himalayas for their probiotic potential. It was achieved through a step-by step approach focused on the technological characterization, evaluation of the probiotic traits and adherence ability. Fifty one LAB isolates from traditional fermented foods and beverages were initially screened for their technological properties and among them twenty isolates were selected. These isolates were further characterized and identified using 16S rRNA gene sequencing as Lactobacillus brevis (7 isolates), Lactobacillus casei (5), Lactobacillus paracasei (2), Lactobacillus buchneri (1), Lactobacillus plantarum (1) and Lactobacillus sp. (3). Identified isolates were evaluated by in vitro methods including survival in gastrointestinal tract, antibiotic susceptibility, antimicrobial activity, cell surface characteristics, exopolysacharride production and haemolytic activity. The results of these experiments were used as input data for Principal Component Analysis; thus, to select the most promising probiotic isolates. Three isolates (L. brevis PLA2, L. paracasei PLA8 and L. brevis PLA16) were found to be most technological relevant and promising probiotic candidates in comparison to commercial probiotic strains. L. brevis PLA2 was selected as best isolate with probiotic potential by in vitro adherence to the human intestinal HT-29 cell line.

Review: Diversity of Microorganisms in Global Fermented Foods and Beverages

Culturalable and non-culturable microorganisms naturally ferment majority of global fermented foods and beverages. Traditional food fermentation represents an extremely valuable cultural heritage in most regions, and harbors a huge genetic potential of valuable but hitherto undiscovered strains. Holistic approaches for identification and complete profiling of both culturalable and non-culturable microorganisms in global fermented foods are of interest to food microbiologists. The application of culture-independent technique has thrown new light on the diversity of a number of hitherto unknown and non-cultural microorganisms in naturally fermented foods. Functional bacterial groups ("phylotypes") may be reflected by their mRNA expression in a particular substrate and not by mere DNA-level detection. An attempt has been made to review the microbiology of some fermented foods and alcoholic beverages of the world.