Časovna dinamika in variacija kemijske sestave posameznih delov korma tara (Colocasia esculenta)

Mergeduš, Andrej

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Title:	Časovna dinamika in variacija kemijske sestave posameznih delov korma tara (Colocasia esculenta)
Authors:	ID Mergeduš, Andrej (Author) ID Kristl, Janja (Mentor) More about this mentor... ID Ivančič, Anton (Comentor)
Files:	DOK_Mergedus_Andrej_2016.pdf (2,53 MB) MD5: 41B46BCE376EB50398ADBE3CF5249241
Language:	Slovenian
Work type:	Doctoral dissertation
Organization:	FKBV - Faculty of Agriculture and Life Sciences
Abstract:	V disertaciji sta predstavljeni dve temi, povezani s procesom nalaganja hranilnih snovi v kormu tara. Prva tema se nanaša na nalaganje snovi v različnih delih korma, druga pa je povezana z dinamiko nalaganja tekom vegetacijske dobe. Poljski poskusi so bili postavljeni v državi Vanuatu na Tihem Oceanu. V poskus (s ciljem proučevanja vsebnosti različnih kemijskih substanc v štirih ključnih delih korma tara) smo vključili 8 kultivarjev iz nacionalne genske banke. Za analizo (povezano s časovno dinamiko razvoja rastlin) smo izbrali 13 kultivarjev. Liofilizirane vzorce smo analizirani na Fakulteti za kmetijstvo in biosistemske vede Univerze v Mariboru. Za analize mineralov smo najprej opravili kislinski razklop. Koncentracije Ca, Mg in Zn smo izmerili s plamensko atomsko absorpcijsko spektrometrijo (FAAS), medtem ko smo K izmerili s plamensko emisijsko spektrometrijo. Analizo Fe, Mn, Cu, Pb in Cd smo izvedli z elektrotermično atomsko absorpcijsko spektrometrijo (ETAAS), P pa smo izmerili po molibdat-vandatni metodi. Vsebnost škroba smo določili po postopku Megazyme in skupni dušik po Kjehldalovi metodi. Nitrate smo določili z ionsko kromatografijo. Rezultati naše raziskave kažejo, da so v zgornjem delu, ki ima ključno vlogo pri vegetativnem razmnoževanju, sorazmerno visoke koncentracije surovih proteinov, P, Mg, Zn, Fe, Mn, Cu in Cd. Za zgornji del so značilne tudi višje vsebnosti nitratov, ki niso zaželeni v prehrani ljudi. Osrednji del, ki je ključen v prehrani ljudi, vsebuje več škroba, K, Mg, Zn, Fe, Cu in Cd. Koncentracije proučevanih hranil v spodnjem delu so bile sorazmerno nizke, z izjemo Ca. Višje vsebnosti Ca in Zn so bile značilne za marginalni del, ki se običajno odstrani z lupljenjem. Globoko lupljenje najbolj vpliva le na vsebnost Ca, saj je Zn prisoten v večjih koncentracijah tudi v zgornjem in/ali centralnem delu. Vrednosti Cr in Pb so bile pod mejo določljivosti. Koncentracije posameznih hranilnih snovi so se zelo razlikovale med posameznimi kultivarji. Med vegetacijo je masa posameznih kormov ves čas naraščala. Vsebnost škroba je naraščala med 5. in 9. mesecem po sajenju (MPS), ko je dosegla maksimum, nato pa je začela padati. Vsebnosti surovih proteinov so bile najvišje v prvih mesecih, ki so bili zajeti z našo raziskavo. Maksimum je bil zabeležen 5. MPS in nato je vsebnost padla. Med posameznimi meseci niso bile evidentirane bistvene razlike v vsebnostih P, K, Mg, Cu in Ca. Glavni razlog so bile velike razlike med posameznimi kultivarji. Vsebnosti Zn so bile najvišje v prvih treh mesecih, vključenih v našo raziskavo (5., 6., 7. MPS), nato je vsebnost začela padati, najnižja vrednost pa je bila izmerjena 13. MPS. Vsebnost Mn je bila navišja 6. MPS in se je signifikantno razlikovala glede na druge mesece. Sorazmerno visoke vsebnosti Mn so bile zaznane tudi 5., 7. in 8. MPS. Vsebnost Fe je bila najvišja 5. MPS. Vsebnost Cd je bila najvišja 5. MPS, nato je začela padati in je ponovno narasla 9. MPS. Glede na dejstvo, da so bili maksimalno izenačeni sadilni materiali in rastni pogoji (okolje), lahko domnevamo, da so bile razlike v rasti v glavnem posledica genetskih razlik med posameznimi kultivarji.
Keywords:	Taro, Colocasia esculenta, korm, kemijska sestava, makroelementi, mikroelementi, škrob, surovi proteini, nitrati
Place of publishing:	Maribor
Year of publishing:	2016
PID:	20.500.12556/DKUM-57697
NUK URN:	URN:SI:UM:DK:W5GYY3A0
Publication date in DKUM:	01.04.2016
Views:	2301
Downloads:	258
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Categories:	FKBV
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Secondary language

Language:	English
Title:	Temporal dynamics and chemical variation of different parts of taro (Colocasia esculenta) corms
Abstract:	The main objective of the presented research was to expand the knowledge about the dynamics of major nutrient accumulation in taro corms. It involves two major topics: the first is associated with the concentration variations of the most important nutritional substances in four crucial parts of corm, and the second topic is associated with the accumulation dynamics of nutrients during the growth season. The trials were planted on one of the experimental fields of VARTC in Vanuatu in the South Pacific. Chemical substances in four corm parts of 8 taro cultivars were studied, and for the analysis associated with the temporal dynamics of accumulation of different nutrients during the growth season, 13 cultivars were selected. Freeze dried samples were sent to the Faculty of Agriculture and Life Sciences at the University of Maribor, Slovenia for further chemical analyses. The analysis of the minerals began with acid digestion. Concentrations of Ca, Mg and Zn were measured by flame atomic absorption spectrometry (FAAS), while K was determined by flame-emission spectrometry. The analyses of Fe, Mn, Cu, Pb and Cd were performed via electrotermic atomic absorption spectrometry (ETAAS), and P was determined by the molybdate-vandat method. The starch content was analysed using the Megazyme method and the total nitrogen with the Kjehldal method. For nitrate content testing we used ion chromatography. The results of our investigation suggest that the upper part, which plays one of the major roles in vegetative propagation, is characterized by relatively high concentrations of crude proteins, P, Mg, Zn, Fe, Mn, Cu and Cd. The upper part is also characterized by higher concentration of nitrates, which are not desirable in the human diet. The central part, which is crucial for human nutrition, is characterized by higher concentrations of starch, K, P, Mg, Zn, Fe, Cu and Cd. The concentrations of the studied nutrients were found to be relatively low in the lower part, with the exception of Ca. Ca and Zn were more concentrated in the marginal and lower parts, which are partly removed by peeling. Deep peeling can affect only Ca because Zn is also present in higher concentrations in the upper and/or central parts. The values of Cd and Pb were below the limit of quantification. The concentrations of the studied nutrients exhibited relatively high differences among cultivars. The weight of the taro corms was increasing throughout the vegetation period. The starch content was increasing from 5 to 9 months after planting (MAP) (when it reached the maximum value) and then it started to decrease. The crude protein content reached its peak during the first months included in our study. The maximum content was recorded at 5 MAP and decreased afterwards. The differences in content of P, K, Mg, Ca and Cu during the growth period were not significant due to the big differences among cultivars. The highest contents of Zn were determined during the first three months of our sampling (5, 6, 7 MAP), whereas the lowest value was determined at 13 MAP. The content of Mn reached its peak at 6 MAP, and was significantly different when compared to the values obtained during other months. A relatively high content of Mn was determined at 5, 7 and 8 of the MAP. The content of Fe reached its maximum at 5 MAP. At 6 MAP, its level decreased and increased again at 9 and 10 MAP. The level of Cd reached its peak at 5 MPS, then it decreased and increased again at 9 MPS. Considering the fact that the planting material and growth conditions were uniform, it can be assumed that the differences in growth were mainly due to the differences associated with the genetic structure of the studied cultivars.
Keywords:	Taro, Colocasia esculenta, corm, chemical composition, macroelements, microelements, starch, crude proteins, nitrate

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