Browsing by Subject "germination"

Sphagnum moss could be used as a substitute for Sphagnum peat as a growing medium. It has the same positive physical properties as peat and it is also a more sustainable option. However, there are some indications that Sphagnum moss may have some inhibitory effects on vascular plant seed germination and seedling development. The aim of this study was to find out whether this is true and due to the low pH of different Sphagnum moss species. The tested moss species were Sphagnum fallax, Sphagnum medium, Sphagnum rubellum and Sphagnum spp. The seed germination on Sphagnum moss substrate was tested with lettuce, radish, basil, pine and ryegrass. Also, two additional seed germination experiments were done with lettuce. Seedling growth experiment on Sphagnum substrate was tested with lettuce. The first germination experiments indicated that the dicotyledon species basil, radish and lettuce are sensitive to the allelopathic effect caused by Sphagnum moss. In the case of ryegrass and pine no indication of seed germination inhibition was found. The two additional germination experiments confirmed that Sphagnum moss and white peat substrates and Sphagnum moss and white peat organic matter/water extracts were inhibiting lettuce seed germination. Added lime didn’t conclusively explain the inhibition in germination percentages of Sphagnum moss substrate when compared to control treatment gauze. Only in the case of radish the raised pH had positive effect on the germination percentage. Therefor it was concluded that the low germination percentage is not explained only by the naturally low pH of Sphagnum mosses and Sphagnum mosses’ other characteristics should be investigated in the future. In the seedling growth experiment done with lettuce on Sphagnum medium growing medium there was no indication of allelopathic effect on seed germination or seedling development. The allelopathic compounds were thought to have been lost in this experiment through leaching when the substrates were watered.

Cyanobacteria of the order Nostocales, including Baltic Sea bloom-forming species Nodularia spumigena, Aphanizomenon flosaquae, Dolichospermum spp., produce resting stages, known as akinetes, under unfavorable conditions. These akinetes can persist in the sediment and germinate if favorable conditions return, simultaneously representing past blooms and possibly contributing to future bloom formation. The present study characterized cyanobacterial akinete survival, germination, and potential toxin production in 40-to-175- year-old brackish water sediment archives in order to understand historical bloom expansion, akinete persistence, and cyanobacteria life cycles in the northern Baltic Sea. Results showed that cyanobacterial akinetes can persist in and germinate from northern Baltic Sea sediment up to 424 and 174 years old, at coastal and open-sea locations respectively. Akinete abundance and viability decreased with age and depth of vertical sediment layers. Increases in sediment organic matter content and akinete abundance largely corresponded with the historical expansion of anthropogenic eutrophication-fueled blooms of cyanobacteria in the northern Baltic Sea, beginning in the mid-twentieth century. The detection of potential hepatotoxin production from akinetes and revived cultures was minimal and restricted to the coastal sediment core. Phylogenetic analysis of culturable cyanobacteria from the coastal sediment core indicated that the majority of strains likely belonged to benthic genera Anabaena. Findings also supported the notion that, in comparison with Nodularia and Aphanizomenon spp. akinetes, Anabaena/Dolichospermum spp. akinetes play a more significant role in their life cycle and bloom initiation strategies. Further research is recommended to accurately quantify akinetes and create a higher rate of toxin gene detection from brackish water sediment samples in order to further describe species-specific benthic archives of cyanobacteria. Overall, measuring cyanobacterial akinete abundance, germination experiments, and genetic methods can be effectively used to determine akinete persistence, viability, and potential toxin production in brackish water sediment samples. This study highlights the prolonged survival of cyanobacterial akinetes in northern Baltic Sea sediment samples, up to 174 years old.

The literature review described the importance of folate enhancement to human health especially to coeliac patients with an introduction to folate analysis, pseudocereals and possible fortification methods. The aim of this study was to study the natural folate enhancement methods in pseudocereal matrix. Pseudocereal materials consisted of buckwheat, amaranth and quinoa, each of which was subjected to three different treatments: germination, fermentation and combined treatment. Total folate determination was based on an official microbiological assay method (Lactobacillus rhamnosus ATCC 7469). Germination of pseudocereals lasted for 4–5 days. Fermentation was conducted using either baking yeast Saccharomyces cerevisiae ALKO743 or LAB Streptococcus thermophilus ABM5097. All germinated whole grain pseudocereals indeed showed a significant increase in total folate content. Specifically, the increase was 5.4-fold in buckwheat, 5-fold in amaranth and 2.6-fold in quinoa. Fermentation of native pseudocereals also enhanced total folate level. As for the combined treatment, the total folate level of germinated seeds did not further significantly increase or decrease in later fermentation period. Although more studies are needed for processing real pseudocereal foods, our study showed great potential of folate enhancement using germination or fermentation.

Niacin is a water-soluble B-group vitamin, and it is a general name for nicotinic acid (NA) and nicotinamide (NAM). It is present in foods as available or bound niacin, which is not absorbable. Currently, the main sources of niacin in Finnish diets are meat and dairy products and with the recommendations to shift towards more plant-based diets, a question is raised if legumes would make potential protein-rich sources of niacin. Therefore, this thesis aimed to investigate legume ingredients as potential protein-rich sources of available niacin. Available niacin was studied from legume ingredients, extrudates, and seeds as a sum of NA and NAM. Stability of available niacin in high moisture extrusion was investigated and the influence of germination on available niacin was studied. Additionally, the propotions of bound niacin in legume flours and seeds were investigated. Available niacin was extracted with mild acid hydrolysis from legume ingredients, extrudates, and seeds. To study bound niacin, total niacin was extracted with acid-alkaline hydrolysis from legume flours and seeds. Ultra-high performance liquid chromatography and fluorescence detection (UHPLC-FLD) with post-column derivatisation were used for the quantification of NA and NAM. Oligosaccharides were analysed using high-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection (PAD) to monitor the germination process. This thesis found that legume ingredients were good sources of available niacin, except for protein isolates. Furthermore, available niacin remained stable in high moisture extrusion and available niacin contents were higher when protein concentrates were favoured as ingredients, rather than protein isolates. Generally, legumes contained more NAM than NA. Germination increased available niacin in faba bean seeds by 30–40%, and oligosaccharide contents decreased. The results of this thesis assumed that legumes contain 20–60% of their niacin in bound forms. However, future research is needed to study bound niacin and niacin bioavailability in legumes, for instance, with a more sensitive and selective tandem-mass spectrometry (LC-MS/MS).

The literature review focused on the proteins and insoluble fibre, ?-(1->4)-galactan, of blue lupin seed and how they degrade during germination. The review also dealt with the food applications of lupins and the harmful substances of lupins: allergens and ?-galactosides. The object of the experimental study was to determine the peptidase activities in the blue lupin seeds at the different stages of germination, classify the peptidases in the seeds and investigate the changes occuring in the proteins during germination and fermentation. The percentage of the water-soluble protein in the seeds was also determined. Blue lupin seeds were soaked in water over night and were germinated in the dark (15 ° C, RH 100 %). Peptidase activities were determined spectrofotometrically using azo-casein as a substrate. Class-specific peptidase-inhibitors (Pepstatin A, PMSF, E-64 and O-FEN) were used for classification of peptidases. Lactobacillus brevis and Lactobacillus rhamnosus were used in the fermentations (35 °C, 24 h) as well as baking yeast. The changes which occured in the proteins during germination and fermentation were investigated by electrophoresis (SDS-PAGE). The Dumas method was used to determine the percentage of the water-soluble protein in the extracts composed of soaked and germinated (2 day) seeds. Peptidase activities increased until the second day of germination and then remained constant until the fourth day. Serine- and aspartic peptidases were identified by inhibitor tests but not cysteine peptidases, even though cysteine peptidases have been previously known to break down legume proteins during germination. The cysteine peptidase inhibitor, E-64, used in this study has been observed earlier to inhibit cysteine peptidases belonging to papain family but not to legumain family. Proteins degraded slightly when the germination continued 4 days, and the degradation continued further during the fermentations. Large polypeptides (MW 45–100 kDa) mainly degraded during germination and fermentation. In addition, 17 kDa polypeptides degraded during fermentation. Possible 20 kDa hydrolysis products also formed during fermentation. The degradation of proteins in fermentations was more efficient when seeds germinated for 2 days were used compared to ungerminated seeds. The content of the water-soluble protein in the soaked seeds and the seeds germinated for 2 days varied between 35–96 %, and the content increased markedly when the pH of the extraction solvent increased from 6 to between 7.5–9.0. Thus the alkalinity of the extraction solution changed the structure of the storage seed proteins to more water-soluble form. The peptidase activity of germinated blue lupin could be applied in varied fermentation processes. The storage proteins of blue lupin were extremely water-soluble, so this discovery could be utilised for manufacturing substitutes for dairy products.