doktorska disertacija
Nataša Lilek (Author), Jasna Bertoncelj (Mentor), Janko Božič (Co-mentor)

Abstract

Z raziskavo smo želeli obsežneje preučiti hranilno vrednost cvetnega prahu osmukanca (CPO) glede na botanično poreklo. Cvetni prah predstavlja edini naravni vir beljakovin v prehrani čebel, zaradi vsebnosti hranilnih snovi in funkcionalnih spojin pa kot čebelji pridelek postaja vse bolj prepoznaven in uporaben tudi v humani prehrani. V raziskavo smo vključili 52 vzorcev CPO iz štirih makroregij Slovenije, pridobljenih v treh obdobjih čebelarske sezone (spomladi, poleti, pozno poleti/jeseni), v letih 2014–2015. Pred analizami smo vzorce mikroskopsko identificirali in določili botanično poreklo. Večina vzorcev CPO je bila večvrstnih na specifičnih pašah in z ročnim prebiranjem smo pridobili tudi enovrstni CPO pravega kostanja (Castanea sativa Mill.), oljne ogrščice (Brassica napus var. oleifera DC.), malega jesena (Fraxinus ornus L.), navadne ajde (Fagopyrum esculentum Moench), navadnega bršljana (Hedera helix L.) in trpotca (Plantago spp. L.). V vseh vzorcih CPO smo določili vsebnost vode, beljakovin, maščob, prehranske vlaknine in pepela v skladu z uradno predpisanimi AOAC metodami. Vsebnost skupnih in izkoristljivih ogljikovih hidratov ter energijsko vrednost smo določili računsko. Vsebnost posameznih aminokislin smo določili z ionsko izmenjevalno tekočinsko kromatografijo, vsebnost elementov pa z rentgensko fluorescenčno spektrometrijo (XRF). Ugotovili smo, da se CPO različnega botaničnega porekla med seboj razlikuje v vsebnosti beljakovin, maščob, netopne prehranske vlaknine, posameznih in skupnih aminokislin ter nekaterih elementov. Rezultate smo modelirali tudi z multivariatnimi statističnimi metodami in določili izstopajoče parametre, ki so specifični za CPO določenega botaničnega porekla, za časovno obdobje pridobivanja in geografsko poreklo. V CPO smo določili tudi vsebnost nebeljakovinskega dušika ter ocenili najbolj ustrezen pretvorbeni faktor za izračun vsebnosti skupnih beljakovin. Ugotovili smo, da uporaba splošnega pretvorbenega faktorja (6,25) pri preračunu daje preveliko vsebnost beljakovin, zato za CPO priporočamo uporabo manjšega specifičnega faktorja z vrednostjo 5,60.

Keywords

cvetni prah;osmukanec;hranilna vrednost;botanično poreklo;geografsko poreklo;kemijska sestava;beljakovine;maščobe;pepel;ogljikovi hidrati;prehranska vlaknina;voda;energijska vrednost;aminokisline;elementi;nebeljakovinski dušik;pretvorbeni faktor;

Data

Language: Slovenian
Year of publishing:
Typology: 2.08 - Doctoral Dissertation
Organization: UL BF - Biotechnical Faculty
Publisher: [N. Lilek]
UDC: 638.178.2:543.61:641.1
COBISS: 1024514639 Link will open in a new window
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Other data

Secondary language: English
Secondary title: Influence of the botanical origin on nutritional value of bee pollen
Secondary abstract: The aim of the study was to determine nutritional value of bee pollen according to its botanical origin. Pollen is the only natural protein source in bees' nutrition, and due to its nutritional value and functional properties, it is also becoming increasingly recognised and useful in human nutrition, as a bee product. Fifty-two samples of bee pollen collected in 2014-2015, from four Slovenian macroregions, during the three periods of the beekeeping season (spring, summer, late summer/autumn) were obtained. Prior analyses, the samples were microscopically identified. Most of bee pollen samples were of polyfloral origin. On specific bee pastures and with manual selection also a monofloral bee pollen samples from sweet chestnut (Castanea sativa Mill.), rapeseed (Brassica napus var. oleifera DC.), flowering ash (Fraxinus ornus L.), buckwheat (Fagopyrum esculentum Moench), common ivy (Hedera helix L.) and plantain (Plantago spp. L.) were obtained. The contents of water, protein, fat, dietary fibre and ash were determined in accordance with the prescribed AOAC methods. The contents of total and available carbohydrates and the energy value were determined by calculation. The content of individual amino acids was determined by ion-exchange liquid chromatography and the content of elements by X-ray fluorescence spectrometry (XRF). The findings of the research indicate differences between bee pollen samples according to botanical origin in content of protein, fat, insoluble dietary fibre, individual and total amino acids and certain elements. The results were also modelled using multivariate statistical methods and the parameters that are particular for a specific botanical origin of bee pollen were determined, as well for period of collection and geographical origin. Content of non-protein nitrogen in bee pollen was determined and the most appropriate conversion factor for total proteins was estimated. The use of the general conversion factor (6.25) in the calculation provides an overestimated content of proteins in bee pollen, so smaller specific conversion factor of 5.60 is recommended.
Secondary keywords: bee pollen;nutritional value;botanical origin;geographical origin;chemical composition;protein;fat;ash;carbohydrate;water;dietary fibre;energy value;amino acids;elements;non-protein nitrogen;conversion factor;
Type (COBISS): Doctoral dissertation
Study programme: 0
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Biotehniška fak.
Pages: XIII, 111, [27] f.
ID: 11420481