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Collaborative project: Development of regional lupine-based bio-flavoring-sauces as salt reduced, glutenfree alternative to soy-products - subproject 1 (FLAVORLOOP)
Project
Project code: 281A400117
Contract period: 01.04.2019
- 31.03.2022
Budget: 312,409 Euro
Purpose of research: Experimental development
Keywords: Lebensmitteltechnologie, food technology, food engineering
"The aim of the FLAVORLOOP project was to optimise the production process of the lupine-based seasoning sauce by characterising the microbiota dynamics and controlling them through process management. As an alternative to soy sauce, lupine-based seasoning sauce is fermented. While in the first step a koji fungus degrades macromolecules into substrates for bacteria and yeasts, during the moromi step the flavour develops over several months at high salt content. In the present work, we investigated the microbiota of lupine-based moromi in terms of dynamics, Einfluss factors and effects on the process and flavour. We were able to analyse the bacterial consortium in a cultivation-independent manner using 16S rRNA gene sequencing. In addition,
bacteria and yeasts could be identified by cultivation. For the analysis of aroma-relevant stoffes, flective compounds were determined by gas chromatography-mass spectrometry (GC-MS). Initially, Candida (C.) guilliermondii and Weissella (W.) paramesenteroides were the most abundant organisms, followed by Tetragenococcus (T.) halophilus, Debaryomcyces (D.) hansenii, Chromohalobacter (C.) moromii, and finally Staphylococcus (S). equorum. The lactic acid bacteria W. paramesenteroides and T. halophilus were able to lower the pH by producing acids, which facilitated the growth of yeasts such as D. hansenii. It is likely that the later increase in pH is caused by S. equorum and the newly described species C. moromii in this project by degrading acids or forming amines and ammonia, respectively. The aroma of the matured moromi consisted mainly of acids and pyrazines, which are also described for wheat-free soy moromi. We were able to show that the microbiota can be influenced by the salt concentration, starter cultures or backslopping (use of ripened moromi) and additional carbohydrate sources such as wheat and buckwheat. At lower salt concentrations, the diversity of the microbiota was higher, bacterial growth accelerated and, again, no spoilage was detected. The use of backslopping accelerated the dynamics of the microbiota, and yeast as starter cultures resulted in very low diversity in both the bacterial and yeast consortium. The addition of wheat or buckwheat allowed the growth of Zygosaccharomyces (Z.) rouxii. Here, the aroma profil was dominated by esters, and pyrazines were partially degraded. The present study provides new insights into the dynamics of the microbiota of lupin-based seasoning sauce and investigates methods to influence this consortium. In this work, 58 T. halophilus isolates were isolated from different lupin moromi approaches. Genome analysis led to the differentiation of six T. halophilus strains. Comparative analyses with isolates from other habitats allowed the grouping of the T. halophilus species into three lineages. The first and largest line includes strains from lupine moromi, fish sauces, soy sauces, buckwheat moromi and cheese rind. The second line contains many strains isolated from soy sauce or fish sauce fermentations. The third lineage consists only of the type strain of T. halophilus subsp. flandriensis.
In order to gain a better understanding of the lifestyle of T. halophilus in its habitat, lupine moromi, a metabolic analysis was carried out using transcriptome analysis of two representatives of the six lupine strains. For this purpose, the growth of the strains TMW 2.2254 and TMW 2.2256 was investigated in the lupine model medium ""LMRS"". Significantly improved growth was observed for both strains when galactose was added to the medium as an extra carbon source instead of glucose. It was striking that both strains used the Leloir pathway and the Tagatose-6-P pathway simultaneously. Transcripts encoding the arginine deiminase degradation pathway were identified in large numbers in the TMW 2.2256 samples. The arginine deiminase degradation pathway is not encoded in the genome of TMW 2,2254. Since this metabolic pathway leads to basic metabolites (urea, NH3), the observed increase in pH during fermentation of TMW 2.2256 can thus also be explained. Accordingly, no increase in pH was observed for the fermentation of TMW 2.2254. To investigate mechanisms of habitat adaptation of T. halophilus strains to lupins as substrate, lupin moromi fermentations were performed with a mixture of T. halophilus strains from different isolation sites (fish fermentation, buckwheat moromi and lupin moromi). After 14 days, strains TMW 2.2254 (lupine moromi) and TMW 2.2264 (lupine moromi) dominated the fermentation. Interestingly, both strains expressed at least one alpha-galactosidase. Thus, the ability to utilise galactose in the substrate seems to be an advantage."
Section overview
Subjects
- Food Processing
