Miso: A traditional nutritious & health-endorsing fermented product

Population Genomics of Aspergillus sojae is Shaped by the Food Environment

Traditional fermented foods often contain specialized microorganisms adapted to their unique environments. For example, the filamentous mold Aspergillus oryzae, used in saké fermentation, has evolved to thrive in starch-rich conditions compared to its wild ancestor, Aspergillus flavus. Similarly, Aspergillus sojae, used in soybean-based fermentations like miso and shochu, is hypothesized to have been domesticated from Aspergillus parasiticus. Here, we examined the effects of long-term A. sojae use in soybean fermentation on population structure, genome variation, and phenotypic traits. We analyzed 17 A. sojae and 24 A. parasiticus genomes (23 of which were sequenced for this study), alongside phenotypic traits of 9 isolates. Aspergillus sojae formed a distinct, low-diversity population, suggesting a recent clonal expansion. Interestingly, a population of A. parasiticus was more closely related to A. sojae than other A. parasiticus populations. Genome comparisons revealed loss-of-function mutations in A. sojae, notably in biosynthetic gene clusters encoding secondary metabolites, including the aflatoxin cluster. Interestingly though, A. sojae harbored a partial duplication of a siderophore biosynthetic cluster. Phenotypic assays showed A. sojae lacked aflatoxin production, while it was variable in A. parasiticus isolates. Additionally, certain A. sojae strains exhibited larger colony diameters under miso-like salt conditions. These findings support the hypothesis that A. parasiticus is the progenitor of A. sojae and that domestication significantly reduced genetic diversity. Future research should explore how wild and food-associated strains influence sensory attributes and microbial community dynamics in fermented soy products.

The Aroma, Taste Contributions, and Flavor Evaluation Based on GC-IMS, E-Nose, and E-Tongue in Soybean Pastes: A Comparative Study

The objective of this study was to assess and compare the characteristics of different soybean pastes by using intelligent sensory analysis. In this study, color, flavor, texture, and taste were regarded as four factors affecting the sensory quality of soybean pastes and the sensory quality of four different soybean pastes was evaluated using fuzzy mathematics. The sensory evaluation scores of samples L, Z, and W were very similar and significantly higher than that of sample Y. Gas chromatography-ion mobility spectrometry (GC-IMS) detected 111 volatile flavor compounds, with acids, alcohol, and ketones having a significantly higher relative content than other compounds, indicating their vital role in the flavor formation process of soybean pastes. Furthermore, partial least squares discriminant analysis (PLS-DA) model analysis identified 41 marker compounds that could differentiate the four types of soybean pastes. The overall odor and flavor profile were detected by the E-nose and E-tongue. These fundamental results lay the groundwork for future research on the similarities and differences between the flavor characteristics of different brands of soybean paste.

Exploring the traditional Chinese diet and its association with health status-a systematic review

CONTEXT

Increased adherence to a traditional Chinese diet (TCD) could reduce the increasing prevalence of noncommunicable diseases. Currently, there is no consistent definition of the TCD in the literature, and its associations with health outcomes have not yet been identified.

OBJECTIVE

This systematic review aimed to assess the definition of the TCD, in the literature, and to evaluate whether the TCD, as described, is associated with health outcomes.

DATA SOURCES

Fourteen databases were searched up to April 25, 2022.

DATA EXTRACTION

Three reviewers (in pairs) independently screened and extracted data. A modified risk-of-bias tool was used to assess the quality of the studies assessing the TCD definition; the Newcastle-Ottawa Scale and the Cochrane Risk-of-Bias tool were used to assess the quality of the observational studies and randomized controlled trials assessing associations between the TCD and health outcomes.

DATA ANALYSIS

Ninety-nine studies were identified that assessed the TCD definition. In at least 75% of the studies, rice and leafy vegetables were consistently reported as food groups that characterize the TCD; the most frequently cited food items were white rice, spinach, bokchoy, and cabbage. Fish and seafood, pork, and pork products were consistently reported in studies exclusively referring to the TCD consumed in southern China (n = 21 studies), whereas wheat and wheat products were commonly reported in studies focusing on northern China (n = 14 studies). Fifteen studies reported on the quantities of food groups that are characteristic of the TCD, but their findings were inconsistent. Of the 99 studies, 54 assessed associations with health outcomes. The TCD was overall inversely associated with obesity risk and weight gain, while relationships between the TCD and other health outcomes were inconsistent.

CONCLUSION

Further studies are needed to determine the quantities of foods consumed in the TCD and to establish a consistent definition for further exploration of the TCD's potential role in preventing non-communicable diseases.

A review on the microbiology of Ethiopian traditional fermented beverage products

Traditional fermented beverages are drinks produced locally on the basis of ethnic knowledge and consumed nearby the locality of production. Ethiopia is a country where a wide variety of traditional fermented beverages are prepared and consumed. Tella, borde, shamita, korefe, cheka, tej, booka, grawa, areki, and keribo are among the traditional fermented beverages in Ethiopia. This review paper highlights the fermentation process and nutritional value of traditional fermented beverages, microorganisms involved in the traditionally ferreted beverages, the nutritional value and shelf-life of fermented beverages, as well as the bioavailability and safety by collecting recent research articles. These traditional fermented beverages significantly enhance health due to the presence of bioactive compounds and their nutritional value relatively greater than those of nonfermented beverages. The fermentation byproducts of yeast and Lactic Acid Bacteria (LAB) increase the acidity of beverages and are crucial for maintaining the quality and characteristics of fermented beverages. It also helps to reduce the amount of toxins and pathogens in food. Similarly, fermented foods contain probiotics, which are beneficial bacteria that help the body to digest food and absorb nutrients. The fermented foods and beverages are important in preventing non-communicable diseases such as cardiovascular diseases, gastrointestinal tissues, immune disorders, and cancer. Overall, the paper provides a comprehensive overview of the current knowledge and tradition on Ethiopian fermented beverages.

Carbon stable isotopes of glucose during the degradation of rice by the koji fungus Aspergillus oryzae

Glucose, a key component of traditional Japanese fermented foods, is derived from rice starch via saccharification by hydrolytic enzymes produced by Aspergillus oryzae. The δ 13C value of glucose reflects that of its rice source. However, the influence of saccharification parameters (glucose concentration, degradation temperature, and reaction time) on glucose δ 13C values is unclear. Here, we investigated the influence of saccharification on the δ 13C value of glucose. Our experiments showed a significant difference in the δ 1³C value of glucose (-27.0 ± 0.1 ‰) obtained from saccharification compared to the ingredient rice (-27.1 ± 0.1 ‰) and remaining solid residue (-27.1 ± 0.1 ‰); however, it did not differ significantly from those of rice koji (-27.0 ± 0.1 ‰) and steamed rice (-27.1 ± 0.1 ‰), despite all values being within 0.1 ‰. Notably, glucose concentration, degradation temperature, and reaction time did not significantly affect glucose δ 13C values. These findings demonstrate the remarkable preservation of glucose δ 13C values. The δ 13C values remain aligned with the original δ 13C value of the rice, even with up to 60 % degradation during A. oryzae saccharification. This persistence of the δ 13C value throughout the process offers a potential tool for authenticating the origin of rice-fermented beverages based on the δ 13C value of their glucose component.

Exploring the microbial diversity of novel misos with metagenomics

Interest in fermented foods, especially plant-based ones, has increased considerably in the last decade. Miso-a Japanese paste traditionally fermented with soybeans, salt, and kōji (Aspergillus oryzae grown on grains or beans)-has gained attention among chefs for its rich flavour and versatility. Some chefs have even been experimenting with making novel misos with untraditional substrates to create new flavours. Such novel fermented foods also offer new scientific opportunities. To explore the microbial diversity of these new traditional foods, we sampled six misos made by the team at a leading restaurant called Noma in Copenhagen (Denmark), using yellow peas (including a nixtamalised treatment), lupin seeds, Swedish Vreta peas, grey peas, and Gotland lentils as substrates. All misos were made with the same recipe and fermented for 3 months at 28 °C. Samples were collected at the end of fermentation for subsequent shotgun metagenomic sequencing and a genome-resolved metagenomic analysis. The taxonomic profile of the samples revealed the presence of kōji mould (A. oryzae) and Bacillus amyloliquefaciens in all misos. Various species of the genera Latilactobacillus, Lactiplantibacillus, Pediococcus and Staphylococcus were also detected. The Metagenome-Assembled Genomes (MAGs) revealed genomic sequences belonging to 12 different species and functional analyses of these MAGs were performed. Notably, we detected the presence of Exiguobacterium-the first reported instance of the genus in miso-and Average Nucleotide Identity (ANI) analyses suggest a potentially new species. We hope these results will improve the scientific literature on misos and contribute to developing novel fermented plant-based foods.

Probiotic significance of Lactobacillus strains: a comprehensive review on health impacts, research gaps, and future prospects

A rising corpus of research has shown the beneficial effects of probiotic Lactobacilli on human health, contributing to the growing popularity of these microorganisms in recent decades. The gastrointestinal and urinary tracts are home to these bacteria, which play a vital role in the microbial flora of both humans and animals. The Lactobacillus probiotic, i.e, Lactobacillus plantarum, Lactobacillus paracasei, Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus rhamnosus, Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus reuteri, and Lactobacillus bulgaricus, are highly recognized for their remarkable probiotic qualities. The current study aims to highlight the beneficial effects of probiotics in different health conditions, point out the research gap, and highlight the future directives for the safe use of these probiotics in several health issues. Most importantly, we have added the most recent literature related to the characteristics and usage of these probiotics in clinical and pre-clinical settings. Based on the above statement, we believe that this is the first report on the application of probiotics in human diseases. By providing a deeper knowledge of the complex functions these probiotics play in both human and animal health, our analysis will direct future studies and developments in this rapidly developing field.