<p>U ovoj disertaciji proučavana je osmotska<br />dehidratacija lista koprive u dva različita<br />osmotska rastvora: 1. vodenom rastvoru<br />saharoze i natrijum hlorida i 2. melasi šećerne<br />repe. Ispitivan je uticaj temperature procesa<br />(20°C, 35°C i 50°C) i vremena imerzije (30, 60<br />i 90 min) na gubitak vode, priraštaj suve<br />materije, sadržaj suve materije, vrednosti<br />aktivnosti vode, mikrobiooške promene,<br />promenu mineralnog sastava (Ca, Mg, Na, K,<br />Fe, Cu, Zn, Mn, Co) i promenu antioksidativne<br />aktivnosti, tokom osmotske dehidratacije lista koprive.<br />Dokazano je da se povećanjem temperature i<br />produženjem vremena trajanja procesa<br />pospešuje prenos mase tj. migracija molekula<br />vode iz tretiranog biljnog materijala u okolni<br />rastvor, i prodiranje molekula rastvorene<br />supstance iz osmotskog rastvora u tretirano<br />biljno tkivo.<br />Snižene aw vrednosti u svim ispitivanim<br />uzorcima ukazuju na pozitivan uticaj osmotske<br />dehidratacije na mikrobiološku stabilnost<br />tretiranog lista koprive. Dobijeni rezultati su<br />pokazali značajno poboljšanje mineralnog<br />sastava lista koprive, dehidriranih u melasi<br />šećerne repe, dok je kod uzoraka tretiranih u<br />rastvoru saharoze i natrijumhlorida uočeno<br />smanjenje sadržaja ispitivanih mineralnih<br />materija. Nasuprot rastvoru saharoze i natrijum<br />hlorida koji je uticao na opadanje ukupne<br />antioksidativnosti osmotski dehidriranih<br />uzoraka, melasa šećerne repe, kao bogat izvor<br />prirodnih antioksidanasa, doprinosi povećanju<br />antioksidativnosti i poboljšanju funkcionalnog<br />kvaliteta dehidriranog produkta.<br />Statističkom obradom rezultata, uočeno je da<br />su optimalni procesni parametri u pogledu<br />efikasnosti procesa, kao i mikrobiološkog,<br />nutritivnog i funkcionalnog kvaliteta osmotski<br />dehidriranog lista koprive, vreme trajanja<br />procesa od 60 min, na temperaturi od 50°C, u<br />melasi šećerne repe kao osmotskom rastvoru.</p> / <p>The osmotic dehydration of the nettle leaf into<br />two different osmotic media was studied in this<br />dissertation: 1. Aqueous solution of sucrose and<br />sodium chloride and 2. Sugar beet molasses.<br />The effects of the process temperature (20 °C,<br />35 °C and 50 °C) and the immersion time (30,<br />60 and 90 min) on water loss, solid gain, dry<br />matter content, water activity, microbial<br />changes, mineral composition (Ca, Mg, Na, K,<br />Fe, Cu, Zn, Mn, Co) and the change in the antioxidant activity during osmotic dehydration<br />of the nettle leaf were studied in this<br />investigation.<br />It has been proved that the increase in<br />temperature and the prolonging of process time,<br />accelerate the mass transfer, i. e., the migration<br />of the water molecules from the treated plant<br />material to the surrounding osmotic solution,<br />and also the penetration of the molecules from<br />the osmotic solution into the treated plant tissue.<br />The reduced aw values in all tested samples<br />indicate the positive effect of osmotic<br />dehydration on the microbiological stability of<br />the treated nettle leaf. The obtained results<br />showed a significant improvement in the<br />mineral composition of the nettle leaf<br />dehydrated in sugar beet molasses, while the<br />decrease in the mineral content was observed in<br />the samples treated with sucrose and sodium<br />chloride solution. Contrary to the sucrose and<br />sodium chloride solution, which negatively<br />affected the overall antioxidative effect of<br />osmotically dehydrated samples, sugar beet<br />molasses contributed to an increase in<br />antioxidantity, being a rich source of natural<br />antioxidants, and it also improves the functional<br />quality of the dehydrated product.<br />Statistical analysis of the obtained experimental<br />results showed that optimal process parameters<br />in terms of process efficiency, as well as<br />microbiological, nutritive and functional quality<br />of the osmotically dehydrated leaf net, could be<br />reached after 60 min of osmotic treatment, at a<br />temperature of 50 °C, using sugar beet molasses<br />as an osmotic solution.</p>
| Identifer | oai:union.ndltd.org:uns.ac.rs/oai:CRISUNS:(BISIS)110257 |
| Date | 21 May 2019 |
| Creators | Knežević Violeta |
| Contributors | Kuljanin Tatjana, Lazić Vera, Tepic Horecki Aleksandra, Radojčin Milivoj, Lončar Biljana |
| Publisher | Univerzitet u Novom Sadu, Tehnološki fakultet Novi Sad, University of Novi Sad, Faculty of Technology at Novi Sad |
| Source Sets | University of Novi Sad |
| Language | Serbian |
| Detected Language | English |
| Type | PhD thesis |
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