A novel milk-clotting enzyme from Aspergillus oryzae and A. luchuensis is an aspartic endopeptidase PepE presumed to be a vacuolar enzyme

Aspergillus oryzae RIB40 has 11 aspartic endopeptidase genes. We searched for milk-clotting enzymes based on the homology of the deduced amino acid sequence with chymosins. As a result, we identified a milk-clotting enzyme in A. oryzae. We expected other Aspergillus species to have a homologous enzyme with milk-clotting activity, and we found the most homologous aspartic endopeptidase from A. luchuensis had milk-clotting activity. Surprisingly, two enzymes were considered as vacuole enzymes according to a study on A. niger proteases. The two enzymes from A. oryzae and A. luchuensis cleaved a peptide between the 105Phe-106Met bond in κ-casein, similar to chymosin. Although both enzymes showed proteolytic activity using casein as a substrate, the optimum pH values for milk-clotting and proteolytic activities were different. Furthermore, the substrate specificities were highly restricted. Therefore, we expected that the Japanese traditional fermentation agent, koji, could be used as an enzyme source for cheese production.

Technological innovation in the winery addressing oenology 4.0: Testing of an automated system for the alcoholic fermentation management

In recent years, the use of automated machine tools in the wine industry has increasingly gained ground to simplify and optimize winemaking, complying with Industry 4.0 requirements. This work aimed to analyse a system for the automatic management of yeast nutrition in alcoholic fermentation in terms of environmental, management, and economic performance in comparison with traditional fermentation management. The automated system is a transportable and easily installable place and start system, equipped with a control unit and rods for the dosage of nutrients, and it works with a memory unit in which fermentative kinetics curves are loaded. The curves are predefined or customized according to oenologists’ needs. Hence, fermentation time, manpower, nutrients, oxygen, water, and energy consumption were evaluated concerning the alcoholic fermentation process. The analysis was carried out considering two different Italian wineries with different working capacities. Furthermore, life cycle assessment methodology and variable costs analysis was performed. Overall, the automated system reveals to be a promising investment, especially if applied to wineries characterized by high-volume tanks, where scale factor played a crucial role. Nutrients used by the automated system are more expensive but more environmentally sustainable than traditional ones.

Bacterial Complexity of Traditional Mountain Butter Is Affected by the Malga-Farm of Production

Bacteria can play different roles affecting flavors and food characteristics. Few studies have described the bacterial microbiota of butter. In the present paper, next-generation sequencing was used to determine bacterial diversity, together with aromatic characteristics, in raw cow milk butter processed by traditional fermentation, in fourteen small farms called “Malga”, located in the Trentino province (Alpine region, North-East of Italy). The physicochemical and aromatic characterization of traditional mountain butter (TMB) showed a low moisture level depending on the Malga producing the butter. Counts of lactic acid bacteria, Staphylococci, and coliforms, as well as diacetyl/acetoin concentrations exhibited changes according to the geographical origin of Malga and the residual humidity of butter. MiSeq Illumina data analysis revealed that the relative abundance of Lactococcus was higher in TMB samples with the highest values of acetoin (acetoin higher than 10 mg/kg). The traditional mountain butter bacterial community was characterized by a “core dominance” of psychrotrophic genera, mainly Acinetobacter and Pseudomonas, but according to ANCOM analysis, a complex bacterial population emerged and specific bacterial genera were able to characterize the TMB bacteria community, with their high abundance, based on the Malga producing the butter.

Pengaruh lama fermentasi terhadap aktivitas antioksidan minuman fermentasi kombucha lengkuas merah (Alpinia purpurata)

Fermentation is one way to increase bioactive compounds in various food products. Kombucha is a beverage product from traditional fermentation which involves fermenting sugar dissolved in tea with symbiotic culture of bacteria and yeast (SCOBY). Kombucha is usually made from a tea solution and not many use spices to make kombucha. In this study, red galangal kombucha will be made. The method used was Completely Randomized Design (CRD) with a variation of fermentation time (0, 2, 4, 6, 8 10) days. Parameters to be analyzed are pH, total phenol, and antioxidant activity. The results obtained are that the length of fermentation affects pH, total phenolic and antioxidant activity of red galangal kombucha drink. The pH of the red galangal kombucha drink decreased along with the length of fermentation. The most optimal total phenolic and antioxidant activity obtained at 8 days of fermentation were 854.64±0.07 gGAE/ml and 89.75±0.06%.

Comparative Analysis of Traditional and Modern Fermentation for Xuecai and Correlations Between Volatile Flavor Compounds and Bacterial Community

Differences in flavor compounds and bacterial communities of Xuecai by traditional and modern fermentation are poorly understood. Allyl isothiocyanate (E9), ethyl acetate (E1), 3-butenenitrile (N1), phenol (P1), ethanol (A1), and 3-(2,6,6-trimethyl-1-cyclohexen-1-yl) acrylaldehyde (L11) were the main flavor compounds that differed between Xuecai produced by traditional and modern fermentation. Among these compounds, the contents of N1 and E9 were higher in modern fermentation Xuecai. Traditional fermentation Xuecai possessed higher contents of A1, P1, E1, and L11. High-throughput sequencing showed that Lactobacillus-related genera was the most abundant genus (50%) in modern fermentation Xuecai. However, in traditional fermentation Xuecai, Halanaerobium (29.06%) and Halomonas (12.96%) were the dominant genera. Halophilic bacteria (HB) positively contribute to the flavor of Xuecai. Carbohydrate metabolism and amino acid metabolism were the most abundant pathways associated with the bacterial communities of the Xuecai. This indicated that Xuecai flavor formation is mainly dependent on protein and carbohydrate degradation. This study provides a novel insight that HB may be important for flavor formation of Xuecai.

Dissecting industrial fermentations of fine flavour cocoa through metagenomic analysis

The global demand for fine-flavour cocoa has increased worldwide during the last years. Fine-flavour cocoa offers exceptional quality and unique fruity and floral flavour attributes of high demand by the world's elite chocolatiers. Several studies have highlighted the relevance of cocoa fermentation to produce such attributes. Nevertheless, little is known regarding the microbial interactions and biochemistry that lead to the production of these attributes on farms of industrial relevance, where traditional fermentation methods have been pre-standardized and scaled up. In this study, we have used metagenomic approaches to dissect on-farm industrial fermentations of fine-flavour cocoa. Our results revealed the presence of a shared core of nine dominant microorganisms (i.e. Limosilactobacillus fermentum, Saccharomyces cerevisiae, Pestalotiopsis rhododendri, Acetobacter aceti group, Bacillus subtilis group, Weissella ghanensis group, Lactobacillus_uc, Malassezia restricta and Malassezia globosa) between two farms located at completely different agro-ecological zones. Moreover, a community metabolic model was reconstructed and proposed as a tool to further elucidate the interactions among microorganisms and flavour biochemistry. Our work is the first to reveal a core of microorganisms shared among industrial farms, which is an essential step to process engineering aimed to design starter cultures, reducing fermentation times, and controlling the expression of undesirable phenotypes.