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Ensiling, in vitro rumen digestion and soaking in slurry altered the germination capacity of Rumex obtusifolius seeds
Anastazija Gselman, Maksimiljan Brus, 2023, original scientific article

Abstract: This study investigated whether the process of ensiling and in vitro digestion in rumen juice, as well as the response to soaking in pig or cattle slurry, affects the germination rate and germination energy of Rumex obtusifolius (broad-leaved dock) seeds. Seeds were subjected to different treatments (200 seeds each) in three experiments: (I) seed ensiling (8 weeks) followed by in vitro rumen digestion (24, 36 and 48 h); (II) the soaking of non-ensiled and ensiled seeds in cattle or pig slurry (2, 4 and 24 weeks); and (III) the in vitro rumen digestion (24, 36 and 48 h) of non-ensiled and ensiled seeds followed by soaking in cattle or pig slurry (24 weeks). The control treatment included untreated seed (0—non-ensiled seed; 0—no in vitro rumen digestion; and 0—no soaking in slurry). Germination tests (germination rate and germination energy) were then conducted in four replicates in the germination chamber under alternating day (20–35 °C for 14 h under light) and night conditions (17–20 °C for 10 h without light) at 75% relative humidity. Experiment I showed that ensiling significantly (p ≤ 0.001) reduced both the germination rate and germination energy of R. obtusifolius seeds. In addition, the length of in vitro digestion duration that the non-ensiled seeds were subjected to significantly (p ≤ 0.001) reduced their germination energy but not the total germination rate. However, the seeds that were subjected to the process of ensiling and in vitro digestion in the rumen lost their germination completely. The Experiment II investigated the effects of soaking non-ensiled seeds in slurry and showed that germination rates were comparable in pig and cattle slurry. Longer soaking times significantly reduced the germination rate, with no germination observed after 24 weeks. The Experiment III considered the combined effects of in vitro digestion and slurry soaking and showed that rumen digestion reduced the proportion of germinable seeds. Germination was inhibited in pig slurry, while in cattle slurry, a decreasing germination rate was observed with increasing digestion time.
Keywords: broad-leaved dock, in vitro rumen digestion, ensiling, pig and cattle slurry, seed germination
Published in DKUM: 05.04.2024; Views: 120; Downloads: 0
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Exposure to Cattle Slurry of Different Concentrations Influence Germination and Initial Growth of Selected Grass and Legume Species
Anastazija Gselman, Vilma Sem, Silva Grobelnik Mlakar, 2023, original scientific article

Abstract: In addition to improving soil quality, the fertilisation of grassland with cattle slurry is often associated with seed dispersal. Most studies focus on the effects of cattle slurry on the germination and early development of weed species, but less is known about how slurry affects the germination process of grasses and forage legumes. The aim of Experiment I of our study was therefore to investigate the influence of soaking time in cattle slurry of different concentrations on Lolium multiflorum, Dactylis glomerata, Trifolium pratense and Trifolium repens. Seeds were soaked in undiluted (100%) and diluted cattle slurries (50% and 25%) for 14, 28, 42, 56, 70 and 84 days. Experiment II was conducted to study the initial growth of studied plants from seeds soaked in cattle slurry of different concentrations for 14 days. After the germination test, which was carried out under controlled conditions, the germination index (GI) was calculated. The results (Experiment I) show that a short soaking in cattle slurry (14 days) has no negative effect on the germination process for all species. However, a longer soaking resulted in significantly reduced and delayed germination, especially in undiluted slurry for grasses and diluted slurries for clovers. The slurry concentration (Experiment II) only influenced the root growth of L. multiflorum. Seedlings grown from seeds soaked in undiluted slurry had a 17% higher relative root length than the control and developed significantly longer root systems than the other two slurry concentrations.
Keywords: cattle slurry, soaking time, seed germination, initial plant growth, Lollium multiflorum, Dactylis glomerata, Trifolium pratense, Trifolium repens
Published in DKUM: 08.12.2023; Views: 274; Downloads: 15
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Jana Simonovska, 2016, doctoral dissertation

Abstract: Pepper (Capsicum annuum L.) as widely distributed vegetable crop in the world is an excellent source of nutritive and biologically active compounds. The characteristic compounds, capsaicinoids and carotenoids, highlight the importance of the red hot pepper varieties and their oleoresin extracts in the food and pharmaceutical industry. In the Ph.D. thesis was studied the possibility for a separate and integral utilization of the red hot pepper for obtaining the oleoresins from pericarp, placenta, seeds and stalk. Pre-treatment of the raw material (drying, separation of anatomical structures i.e. pericarp, placenta and seeds, and determination of theirs physico-chemical characteristics and determination of the he characteristic bioactive compounds: capsaicinoids, carotenoids and volatiles was studied, also. The second part of the Ph.D. thesis was focused of the determination of the optimal conditions for isolation of the bioactive capsaicinoids and coloured compounds, through comparative following of the thermodynamical parameters by application of organic solvents and supercritical fluids. Influence of the working parameters: temperature, time, pressure, solid to liquid phase ratio, density, type of solvents, and particle size of raw material on the yield of extract and content of capsaicinoids, colour compounds and volatiles was studied. Modelling of the experimental phase data by application of mathematical methods was performed. Re-utilization of seed and stalk from red hot pepper in form of extracts for development of new formulations as edible films, biopesticides and nanoemulsions was studied, also.
Keywords: red hot pepper, pericarp, placenta, seed, stalk, extraction, sub- and supercritical fluids, bioactive compounds, volatiles, re-utilization, edible films, biopesticides, nanoemulsions
Published in DKUM: 08.11.2016; Views: 2020; Downloads: 167
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Antioxidant and antimicrobial activity of guarana seed extracts
Lucija Majhenič, Mojca Škerget, Željko Knez, 2007, original scientific article

Abstract: The antioxidant and antibacterial activities of guarana (Paullinia cupana) seed extracts were determined. The seeds were extracted with water, methanol, 35% acetone and 60% ethanol at room (TR) and at boiling (TB) temperature of solvent.Extracts were analyzed for the contents of caffeine and catechins, epicatechin (EC), catechin (C) and epicatechin gallate (ECG), by high performance liquid chromatography (HPLC). The contents of total phenols (according to the Folin-Ciocalteu procedure) and proanthocyanidins were analysed by UV spectrophotometry. The guarana seed water extract obtained at room temperature contained higher amounts of caffeine and catechins than did alcoholic guarana seed extracts. The antioxidant and radical-scavenging activities of guarana seed extracts were evaluated using the ß-carotene-linoleic acid emulsion system and the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH ). All tested guarana seed extracts displayed strong antioxidant and radical-scavenging properties. The guarana seed extracts were tested against three food-borne fungi: Aspergillus niger, Trichoderma viride and Penicillium cyclopium, and three health-damaging bacteria: Escherichia coli, Pseudomonas fluorescens and Bacillus cereus by theagar well diffusion and broth dilution assay. The alcoholic guarana seed extracts displayed stronger antimicrobial activity against all tested microorganisms than did water extracts. Results presented here may suggest that seed extracts of guarana possess strong antimicrobial and antioxidant properties, and they can therefore be used as a natural additive in food, cosmetic and pharmaceutical industries.
Keywords: chemical processing, guarana extract, Paullinia cupana, seed extracts, antimicrobial properties, antioxidative properties
Published in DKUM: 31.05.2012; Views: 2050; Downloads: 118
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Kinetics of supercritical carbon dioxide extraction of borage and evening primrose seed oil
Petra Kotnik, Mojca Škerget, Željko Knez, 2006, original scientific article

Abstract: In the present work, high-pressure extraction of borage (Borago officinalis L.) and evening primrose (Oenothera biennis L.) seed oil, containing the valuable -linolenic acid (GLA), has been investigated. Extraction was performed with supercritical carbon dioxide on a semi-continuous flow apparatus at pressures of 200 and 300 bar, and at temperatures of 40 and 60 °C. A constant flow rate of carbon dioxide in the range from 0.17 to 0.20 kgžhwas maintained during extraction. The extraction yields obtained using dense CO2 were similar to those obtained with conventional extraction using hexane as solvent. The composition of extracted crude oil was determined by GCanalysis. The best results were obtained at 300 bar and 40 °C for both seed types extracted, where the quality of oil was highest with regard to GLA content. The evening primrose seed oil extracted with supercritical fluid extraction was particularly rich in unsaturated fatty acidsČ up to 89.7 wt-% of total free fatty acids in the oil. The dynamic behavior of the extraction runs was analyzed using two mathematical models for describing the constant rate period and the subsequent falling rate period. Based on the experimental data, external mass transfer coefficients, diffusion coefficients and diffusivity in solid phase were estimated. Results showed good agreement between calculated and experimental data.
Keywords: chemical processing, high pressure technology, supecritical CO2, seed oil extraction, evening primrose, borage, free fatty acids, kinetics, modeling
Published in DKUM: 31.05.2012; Views: 2192; Downloads: 107
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