magistrsko delo
Larisa Dušak (Author), Rajko Vidrih (Reviewer), Mojca Korošec (Mentor), Polona Jamnik (Co-mentor)

Abstract

V okviru magistrskega dela smo ugotavljali vpliv časa mlečnokislinske fermentacije na vsebnost hranljivih snovi v mikroalgi Arthrospira platensis. Za inokulum smo uporabili mlečnokislinsko bakterijo Lactobacillus plantarum. Opravili smo fermentacije v treh bioloških ponovitvah. Mlečnokislinska fermentacija na pripravljenih vzorcih mikroalge je potekala pri anaerobnih pogojih, 72 ur v inkubatorju pri temperaturi 30 °C. Vsebnost dušika smo določali z metodo po Kjeldahlu. Za analizo neproteinskega dušika smo predhodno uporabili ekstrakcijo s triklorocetno kislino. Proteinski dušik smo izračunali iz razlike med celokupnim in neproteinskim dušikom. Vrednost smo pomnožili s splošnim empiričnim faktorjem 6,25 in izračunali vsebnost beljakovin. Vsebnost pepela smo določali s suhim sežigom pri 550 °C. Vsebnost skupnih maščob smo določali z ekstrakcijo po Soxhletu, vsebnost prehranske vlaknine pa z encimsko-gravimetrično metodo AOAC 991.43. Ugotovili smo, da mlečnokislinska fermentacija vpliva na vsebnost nekaterih prehransko pomembnih snovi v mikroalgi. Vsebnost neproteinskega dušika se je z mlečnokislinsko fermentacijo povečala, vendar to ni vplivalo na vsebnost proteinskega dušika oziroma beljakovin. Vsebnost netopne vlaknine se je s časom fermentacije značilno zmanjšala, med tem ko se vsebnost topne vlaknine bistveno ni spreminjala. Posledično se je s časom fermentacije zmanjšal delež netopne frakcije v skupni prehranski vlaknini. S fermentacijo se je značilno povečala vsebnost maščob, vendar je to s prehranskega stališča nepomembno zaradi nizke vsebnosti maščob.

Keywords

mikroalge;Arthrospira platensis;spirulina;mlečnokislinska fermentacija;Lactobacillus plantarum;hranilna vrednost;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UL BF - Biotechnical Faculty
Publisher: [L. Dušak]
UDC: 579.67:582.232:641.1:602.42
COBISS: 32437763 Link will open in a new window
Views: 468
Downloads: 116
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Other data

Secondary language: English
Secondary title: Effect of lactic acid fermentation on nutritional value of microalgae Arthrospira platensis
Secondary abstract: In the frame of the master’s thesis, we investigated the influence of the duration of lactic acid fermentation on the nutritional value of microalgae Arthrospira platensis. Lactic acid bacteria Lactobacillus plantarum was used for the inoculum. We performed fermentations in three biological replicates. The lactic acid fermentation on the prepared samples took place under anaerobic conditions; for 72 hours in an incubator at 30 °C. The nitrogen content was determined by the Kjeldahl method. Trichloroacetic acid extraction was previously used for the analysis of non-protein nitrogen. The content of protein nitrogen was calculated, which we then multiplied by a general empirical factor 6,25 and calculated the proteins. The ashes were determined by burning the sample over a gas burner and annealing it in a furnace at 550 °C. Total fat content was determined by an extraction in a Soxhlet apparatus and the fibres content by enzyme-gravimetric method AOAC 991.43. We found out that lactic acid fermentation influenced some nutritionally important compounds of microalgae. The content of non-protein nitrogen increased during lactic acid fermentation, but this did not affect the content of protein nitrogen and protein. The insoluble fiber content decreased significantly with fermentation time, while the soluble fiber content did not change significantly. As a result, the ratio of insoluble to total fibre has decreased. Fermentation provoked a significant increase of fat content, although these changes are insignificant from nutritioanl point of view due to the very low fat content.
Secondary keywords: microalgae;Arthrospira platensis;spirulina;lactic acid fermentation;Lactobacillus plantarum;nutritional value;
Type (COBISS): Master's thesis/paper
Study programme: 0
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Biotehniška fak., Oddelek za živilstvo
Pages: XI, 49 f., [3] f. pril.
ID: 12053343