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Lupine (Lupinus sp.) is a valuable source of plant proteins. There is little knowledge on the impact of food processing on composition and sensory properties of lupine products. In this research, we investigated the impact of fermentation with five starters of lactic acid bacteria on the sensory quality and flavor-active compounds in dairy analogues prepared from sweet lupine (Lupinus angustifolius L.). The sensory qualities of unfermented and fermented products were studied with generic descriptive analysis and affective tests. Acids and sugars were analyzed with GC-FID and volatiles with HS-SPME-GC-MS and GC-O. Fermentation increased sourness and 'vinegar' odor and reduced the 'beany' odor and flavor as well as the unpleasantness of flavor. Formation of volatiles during the fermentation was dependent on the starters. However, all fermentations increased the contents of lactic, acetic, and hexanoic acids, while reducing the contents of hexanal, described as 'grassy' in the unfermented lupine sample.

Faba bean (Vicia faba L.) is a grain legume that provides possibilities to increase local protein self-sufficiency both as feed and food in areas where possibilities for cultivation of other protein crops are limited. However, full ripening may not be achieved and storage of the moist beans by crimping and ensiling provides an economic alternative to drying, and is well suited for animal feeding. The objectives of the current experiment were to evaluate the effects of moisture content and various silage additives on the fermentation quality, aerobic stability and fate of bioactive compounds of ensiled crimped faba beans in a pilot scale ensiling experiment. Faba beans were combine harvested at moisture level of 443 g/kg and crimped prior to ensiling. The following additive treatments were applied using three replicates: 1) control (CON), 2) two commercial lactic acid bacteria inoculants as mixture (LABmix), 3) In-house LAB inoculant (LABLuke), 4) Formic acid based product (FA) and 5) Salt based product (Salt). Further, two of the additive treatments were prepared with additional moisture: 6) Control with tap water addition (CON + w) and 7) LABmix with tap water addition (LABmix + w). The beans ensiled without additive showed elevated pH, butyric acid and ethanol concentrations and proportion of ammonia N in total N. Addition of water further decreased the fermentation quality. The LAB inoculants improved the fermentation quality of the beans compared to CON. The fermentation was effectively restricted when FA was used. Both LAB and chemical additives improved aerobic stability compared to CON and Salt was especially effective in improving aerobic stability. Vicine disappeared totally during the ensiling period and also convicine was effectively degraded. It seems that promoting microbial activity in the silo either by LAB inoculation or increased moisture promoted the degradation of convicine, while chemical additives decreased the degradation of it. Total and particularly soluble proanthocyanidins were also degraded during the ensiling period. Crimping and ensiling is an alternative preservation method for faba beans which eliminates the energy consumption and investments required for drying. In addition, benefits regarding the concentrations of bioactive compounds may be expected.

This study focused on defining the differences in L. plantarum gene expression levels in different media and in different growth phases using an easy and cost-efficient monitoring of gene expression. A macroarray based on a group of selected L. plantarum genes, 178 genes belonging to 18 main groups, printed onto a nitrocellulose filter was designed in this work. Using the macrofilters designed, the expression of a selected set of L. plantarum genes was assayed in synthetic MRS medium and in extracted carrot juice. To compare the potential differences of starter gene expression in hygienic and contaminated cultivation media, the L. plantarum strain was cultivated in both sterile and contaminated (yeast and Escherichia coli) MRS and carrot juice. The number of genes found to be regulated as a function of growth was clearly higher in MRS-based growth medium than in carrot juice, In carrot juice, expression of the gene encoding malolactic enzyme (MLE), which makes L. plantarum an advantageous microbe in e.g. wine making, was found to be upregulated in logarithmic phase of growth. The current study demonstrated that macroarrays printed on nitrocellulose filters with simple robotic systems can be analyzed by standard laboratory equipment and methods usually available in molecular laboratories. Using this technology, rapid and cost-efficient analysis of genome function of L. plantarum can be carried out e.g. in developing regions, where lactic acid fermentation of food and feed matrices is a common practice.

The preparation of sour milk products has been known in all parts of the world as a means of preserving milk against spoilage. Traditional sour milk foods were obtained by spontaneous acidi…cation with lactic acid bacteria (LAB) naturally present in milk, which during their growth reduce the pH and denature milk proteins, causing appearance and texture changes in the product. In certain cases, yeasts and molds, which occur along with LAB, give a special feature to the sour milk product. Due to the speci…c characteristics of milk and LAB and the conditions of fermentation, various types of regionally speci…c fermented milk have been developed throughout the world.

Propionic acid bacteria (PAB) are important as starter cultures for the dairy industry in the manufacture of Swiss-type cheeses, in which they are involved in the formation of eyes and are responsible for the typical flavour and aroma. These characteristics are mainly due to the classical propionic acid fermentation, but also the conversion of aspartate to fumarate and ammonia by the enzyme aspartase and the subsequent reduction of fumarate to succinate, which occur in dairy Propionibacterium freudenreichii ssp. shermanii and ssp. freudenreichii starter strains. Additionally, the metabolism of free amino acids may be partly responsible for secondary fermentation and the subsequent split defects in cheese matrix. Here a method for aspartase activity was established and a number of dairy propionibacteria belonging to P. freudenreichii ssp. shermanii and freudenreichii were screened for this enzyme activity. A wide range of aspartase activity could be found in PAB isolates originating from cheese. The majority, i.e. 70% of the 100 isolates tested, showed very low levels of aspartate activity.

Aims of the study were to characterize two Lactobacillus plantarum-related strains, Lact. plantarum and Lactobacillus paraplantarum isolated from fermented vegetables and, for their potential use as starter strains, compare their growth in various food matrices. Species-level identification of the strains belonging to the Lact. plantarum group was performed by multiplex-PCR with species-specific primers and generation of distinct genotypic profiles was carried out by PFGE-based DNA-fingerprinting. Growth profiles were determined in various food and feed matrices. Compared to Lact. plantarum, Lact. paraplantarum reached higher cell densities in all plant-based matrices and MRS broth. On the contrary to the good growth in plant-based matrices and MRS, poor growth was observed in unprocessed milk. Supplemented lactose did not improve the growth of either tested strain, while predigestion of milk proteins with Lactobacillus helveticus or addition of casitone proved to be an effective means to enhance growth. To find out the applicability of molecular methods, the strains were transformed with replicative plasmids by electroporation. To our knowledge, this is a first report of the electrotransformation of Lact. paraplantarum with a recombinant plasmid.

Development of molecular methods has enabled detailed studies of the proteolytic system of Lactobacillus helveticus, which has a central role in the release of bioactive peptides during the fermentation of milk. The impact of general aminopeptidase (PepN) and X-prolyl dipeptidyl aminopeptidase (PepX) activity of L. helveticus on the level of angiotensin I-converting enzyme (ACE) inhibitory activity in fermented milk was elucidated by taking advantage of peptidase-negative derivatives of L. helveticus CNRZ32. According to the results, increased level of ACE-inhibitory activity was attained in milk fermented by the peptidase-deficient mutants. The ACE-inhibitory activity determined with the PepN-deficient strain decreased towards the end of fermentation, suggesting that PepN gives rise to a provisional accumulation of ACE-inhibitory peptides before their hydrolysis to shorter peptides or free amino acids. The ACE-inhibitory activity determined with the PepX-deficient strain increased throughout the fermentation, indicating specific blocking of the further hydrolysis of ACE-inhibitory peptides.

Aims: Phenotypic and molecular methods were used to identify and compare the strain composition of three industrial dairy starters used for the manufacture of viili. Methods and Results: Preliminary differentiation was made by phenotypic methods. Genotypic differentiation was carried out using polymerase chain reaction (PCR) and further characterization at strain level by pulsed-field gel electrophoresis (PFGE). The isolates could be assigned as acid-producing Lactococcus lactis strains of both lactis and cremoris subspecies, and aroma producers, identified as L. lactis subsp. lactis biovar diacetylactis and Leuconostoc mesenteroides. PCR analysis discriminated between the lactococcal subspecies, and cluster analysis of the digestion patterns of PFGE analysis revealed different genotypes in each subspecies. Each Leuconostoc-genotype seemed to be specific to only a single starter mix. Conclusions: The work proved that in addition to L. lactis subsp. lactis biovar diacetylactis and Leuc. mesenteroides subsp. cremoris, commercial viili starters of traditional origin may contain (i) only L. lactis subsp. cremoris, (ii) both L. lactis subsp. cremoris and L. lactis subsp. lactis as a minority, and – as a new discovery – (iii) only L. lactis subsp. lactis. Significance and Impact of the Study: The results obtained give an overview of the microbial population of viili starters and can be exploited in the development of optimized starter cultures for industrial-scale manufacture of viili.

Vegetable by-products could potentially be suitable to be used as feeds in animal diets, which in general would strengthen the sustainability of both food and feed systems. Two experiments were performed with the objective to evaluate the aerobic spoilage via visual inspection and short term ensiling process of carrot by-products with silage additives (lactic acid bacteria [LAB] inoculants or formic acid [FA]). In the first experiment (Exp. 1), carrot by-product was treated with five additives including a control without additive, two commercial LAB inoculants (heterofermentative and homofermentative), an in-house isolated LAB mixture and a commercial FA based product. Second experiment (Exp. 2) used a 2 × 3 factorial design (type of raw material [carrot by-product with or without pieces] and additive treatment [control, heterofermentative LAB inoculant or FA based product]). Use of FA restricted lactic acid fermentation indicated by the high residual water soluble carbohydrate concentration while simultaneously stimulating ethanol production. LAB inoculants were not able to efficiently affect quality of ensiled carrot by-products. Use of FA also delayed the spoilage of the fresh carrot by-product particularly in Exp. 1.