Optimizacija tehnološkog postupka proizvodnje senfa sa stanovišta stvaranja aromatskog kompleksa

nutritionally valuable and that their functional properties provide a positive effects on human health. Mustard is not just a spice that enriches the taste and smell to many foods, but it is also the foodstuff that greatly improves the metabolic system of a human body and its components contribute to the prevention of some diseases. Within this Ph.D. Dissertation a technological process of production of four kinds of mustard is optimized from the aspect of the aromatic complex formation. Mild mustard paste, mustard paste with herbs, barbecue mustard paste and chili mustard paste were produced. Before the start of production microbiological analyses were done on the raw materials. Quality control of the sunflower oil, which is a component in mustard paste, was analyzed as well. Each of the four samples was obtained after a detailed examination of series of test recipes, adjustment of the taste, aroma, color and consistency with the sensory evaluation team of professional tasters. The best samples were sensory evaluated and compared to the same type of mustard that can be found in the domestic market. Sensory evaluation was conducted with the descriptive analytical method, system of scoring. The results were statistically analyzed. All samples were analyzed by physico-chemical analyses, microbiological analyses, physical-chemical analyses of contaminants (the contents of pesticide residues, heavy metals and mycotoxins) and energy value of the sample. All results showed that the samples of four kinds of mustard were in accordance with the Regulation on quality and other requirements for mustard, Regulation on the quality and conditions of usage of additives in food and the other requirements for additives and their mixtures, Regulation on microbiological food safety in the market and Regulation on the amount of pesticides, metals and metalloids and other toxic substances, chemotherapeutics, anabolics and other substances which can be found in food. The purpose of the experiment was investigation of sinalbin degradation products in produced mild yellow mustard paste. The samples were extracted in a Soxhlet extraction system and analyzed by gas chromatography - mass spectrometry (GC-MS) techniques. The results were compared with the analysis of the ground white mustard seeds which were dominant fatty acids, originally present in the white mustard seeds, are also present in the mustard paste condiment made from this plant. The most abundant sinalbin degradation product in yellow mustard paste was 4-(hydroxymethyl)phenol. Other compounds identified in this sample were: 4-methyl phenol, 4-ethyl phenol, 4-(2-hydroxyethyl)phenol and 2-(4-hydroxyphenyl) ethanoic acid...je nutritivno vredna i koja svojim funkcionalnim svojstvima obezbeđuje pozitivan uticaj na zdravlje ljudi. Senf nije samo začin kojim se obogaćuju ukus i miris mnogim jelima, već je namirnica koja umnogome poboljšava metabolički sistem organizma i koja svojim komponentama doprinosi prevenciji nekih bolesti. U okviru ove doktorske disertacije optimizovan je tehnološki postupak proizvodnje četiri vrste senfa sa aspekta stvaranja aromatskog kompleksa. Proizvedeni su blagi senf, senf sa začinskim biljem, senf za roštilj i senf sa čilijem. Pre početka proizvodnje urađena su mikrobiološka ispitivanja sirovina koje ulaze u sastav receptura i kontrola kvaliteta suncokretovog ulja koje je komponenta u proizvodnji senfa. Svaki od ova četiri uzorka je dobijen nakon ispitivanja niza probnih receptura, korigovanjem ukusa, mirisa, boje i konzistencije uz senzorno ocenjivanje stručnog tima degustatora. Najbolji uzorci su senzorno ocenjivani i u odnosu na iste vrste senfa koji se mogu naći na domaćem tržištu. Senzorno ocenjivanje je obavljeno na osnovu deskriptivnog analitičkog bod sistema. Rezultati su statistički obrađeni. Na svim uzorcima su urađena fizičko-hemijska, mikrobiološka ispitivanja, kao i fizičkohemijska ispitivanja kontaminanata (sadržaj ostataka pesticida, teških metala i mikotoksina) i određena je energetska vrednost uzorka. Svi rezultati su pokazali da su uzorci četiri vrste senfa u skladu sa Pravilnikom o kvalitetu i drugim zahtevima za senf, Pravilnikom o kvalitetu i uslovima upotrebe aditiva u namirnicama i o drugim zahtevima za aditive i njihove mešavine, Pravilnikom o mikrobiološkoj ispravnosti namirnica u prometu i Pravilnikom o količinama pesticida, metala i metaloida i drugih otrovnih supstancija, hemioterapeutika, anabolika i drugih supstancija koje se mogu nalaziti u namirnicama. Eksperiment je imao za cilj da se izvrši analiza degradacionih produkata sinalbina u proizvedenom blagom senfu. Uzorci su ekstrahovani u Soxhlet-ovom sistemu, a potom analizirani metodama gasne hromatografije-masene spektrometrije. Rezultati su poređeni sa rezultatima mlevenog semena bele slačice koje je korišćeno u procesu proizvodnje senfa. Ovi rezultati ukazuju na to da su dominantne masne kiseline, prvobitno prisutne u semenu bele slačice takođe prisutne i u gotovom proizvodu, blagom senfu. Najobilniji degradacioni proizvod sinalbina u senfu bio je 4-(hidroksimetil)fenol. Druga identifikovana jedinjenja u senfu bila su: 4-metil fenol, 4-etil fenol, 4-(2-hidroksietil)fenol i 2-(4-hidroksifenil) etanska kiseline..

Kinetika sušenja i kvalitet jabuke sorti Granny Smith, Idared i Jonagold

Apple is nutritionally valuable and present as fresh fruit in human nutrition throughout the year. Also apple is a raw material in food processing, primarily in the production of juices, nectars, refreshing soft drinks, marmalades, jams, compotes, apple cider vinegar and dried fruits. In the last decade on the world market there is a great interest in dried apple products (commercially called apple chips). During preservation by drying the technological process aimed at the final product of optimal quality is required. The subject of this paper is the kinetics of the apple cv. Granny Smith, cv. Idared and cv. Jonagold drying in laboratory dehydrator for the purpose of pinpointing at which level of humidity the maximum speed of evaporation is achieved and at which level of humidity apple slices begin to change in colour and geometric shape. Parameters of the drying process were the same for all three cultivars, 3hrs at air temperature of 70oC and 5hrs at air temperature of 50o. The amount of evaporated water is expressed in relative and absolute units of measure. The purpose of this paper is to determine which one of the three tested cultivars provides the best properties for drying, i.e. in terms of oxidation of polyphenolic compounds to find the cultivar which will provide that the final product is technologically and organoleptically the most acceptable. The results showed that the sample cv. Granny Smith expressed the least oxidation of polyphenolic compounds (browning), curved edges and shrivelled apple slices. After that the sample cv. Jonagold followed. The sample cv. Idared showed the worst results. Following the drying kinetics of all three samples, it can be concluded that the cultivars Granny Smith and Jonagold were achieving the lower maximum speed of evaporation, unlike the cultivar Idared. The cultivars Granny Smith and Jonagold have attained consistent drying and in this way the technological process was finished with a smaller temperature stress for plant tissue, resulting in a much better quality of the final product.Nutritivno vredni plodovi jabuke se koriste kao stono voće tokom cele godine, ali i kao sirovina u prehrambenoj industriji za proizvodnju sokova, nektara, osvežavajućih bezalkoholnih pića, marmelada, džemova, kompota, jabukovog sirćeta i sušenih plodova. Poslednjih decenija na svetskom tržištu postoji veliko interesovanje za sušene proizvode od jabuke (marketinški nazvane čips od jabuke). Pri konzervisanju sušenjem od tehnološkog postupka se zahteva da obezbedi gotov proizvod optimalnog kvaliteta. U radu je izučavana kinetika sušenja jabuke sorti Granny Smith, Idared i Jonagold u laboratorijskom dehidratoru sa ciljem da se uoči pri kojim sadržajima vlage dolazi do postizanja maksimalne brzine isparavanja i pri kojoj vlažnosti kolutovi jabuke počinju da menjaju boju i geometrijski oblik. Parametri procesa sušenja su isti za sve tri sorte, 3 h na temperaturi vazduha od 70oC i 5 h na temperaturi vazduha od 50oC. Količina isparene vode je izražena u relativnim i apsolutnim jedinicama mere. Cilj rada je da se utvrdi koja od ispitivane tri sorte pruža najbolje mogućnosti za sušenje, tj. da se sa aspekta oksidacije polifenolnih jedinjenja pronađe sorta koja omogućava da gotov proizvod bude tehnološki i organoleptički najprihvatljiviji. Rezultati su pokazali da je uzorak sorte Granny Smith pored najmanje izražene oksidacije polifenolnih jedinjenja (tamnjenje) imao i najmanje izraženo povijanje ivica i smežuravanje kolutova, potom sledi sorta Jonagold, a najlošije rezultate je pokazao uzorak sorte Idared. Prateći kinetiku sušenja sva tri uzorka zaključuje se da su sorte Granny Smith i Jonagold postigle manje maksimalne brzine isparavanja, za razliku od sorte Idared. Sorte Granny Smith i Jonagold su imale ravnomerno sušenje i na taj način tehnološki postupak se vršio sa manjim temperaturnim stresom za biljno tkivo što je rezultiralo mnogo boljim kvalitetom gotovog proizvoda

Optimization of technological process of mustard production from the aspect of the aromatic complex formation

je nutritivno vredna i koja svojim funkcionalnim svojstvima obezbeđuje pozitivan uticaj na zdravlje ljudi. Senf nije samo začin kojim se obogaćuju ukus i miris mnogim jelima, već je namirnica koja umnogome poboljšava metabolički sistem organizma i koja svojim komponentama doprinosi prevenciji nekih bolesti. U okviru ove doktorske disertacije optimizovan je tehnološki postupak proizvodnje četiri vrste senfa sa aspekta stvaranja aromatskog kompleksa. Proizvedeni su blagi senf, senf sa začinskim biljem, senf za roštilj i senf sa čilijem. Pre početka proizvodnje urađena su mikrobiološka ispitivanja sirovina koje ulaze u sastav receptura i kontrola kvaliteta suncokretovog ulja koje je komponenta u proizvodnji senfa. Svaki od ova četiri uzorka je dobijen nakon ispitivanja niza probnih receptura, korigovanjem ukusa, mirisa, boje i konzistencije uz senzorno ocenjivanje stručnog tima degustatora. Najbolji uzorci su senzorno ocenjivani i u odnosu na iste vrste senfa koji se mogu naći na domaćem tržištu. Senzorno ocenjivanje je obavljeno na osnovu deskriptivnog analitičkog bod sistema. Rezultati su statistički obrađeni. Na svim uzorcima su urađena fizičko-hemijska, mikrobiološka ispitivanja, kao i fizičkohemijska ispitivanja kontaminanata (sadržaj ostataka pesticida, teških metala i mikotoksina) i određena je energetska vrednost uzorka. Svi rezultati su pokazali da su uzorci četiri vrste senfa u skladu sa Pravilnikom o kvalitetu i drugim zahtevima za senf, Pravilnikom o kvalitetu i uslovima upotrebe aditiva u namirnicama i o drugim zahtevima za aditive i njihove mešavine, Pravilnikom o mikrobiološkoj ispravnosti namirnica u prometu i Pravilnikom o količinama pesticida, metala i metaloida i drugih otrovnih supstancija, hemioterapeutika, anabolika i drugih supstancija koje se mogu nalaziti u namirnicama. Eksperiment je imao za cilj da se izvrši analiza degradacionih produkata sinalbina u proizvedenom blagom senfu. Uzorci su ekstrahovani u Soxhlet-ovom sistemu, a potom analizirani metodama gasne hromatografije-masene spektrometrije. Rezultati su poređeni sa rezultatima mlevenog semena bele slačice koje je korišćeno u procesu proizvodnje senfa. Ovi rezultati ukazuju na to da su dominantne masne kiseline, prvobitno prisutne u semenu bele slačice takođe prisutne i u gotovom proizvodu, blagom senfu. Najobilniji degradacioni proizvod sinalbina u senfu bio je 4-(hidroksimetil)fenol. Druga identifikovana jedinjenja u senfu bila su: 4-metil fenol, 4-etil fenol, 4-(2-hidroksietil)fenol i 2-(4-hidroksifenil) etanska kiseline...nutritionally valuable and that their functional properties provide a positive effects on human health. Mustard is not just a spice that enriches the taste and smell to many foods, but it is also the foodstuff that greatly improves the metabolic system of a human body and its components contribute to the prevention of some diseases. Within this Ph.D. Dissertation a technological process of production of four kinds of mustard is optimized from the aspect of the aromatic complex formation. Mild mustard paste, mustard paste with herbs, barbecue mustard paste and chili mustard paste were produced. Before the start of production microbiological analyses were done on the raw materials. Quality control of the sunflower oil, which is a component in mustard paste, was analyzed as well. Each of the four samples was obtained after a detailed examination of series of test recipes, adjustment of the taste, aroma, color and consistency with the sensory evaluation team of professional tasters. The best samples were sensory evaluated and compared to the same type of mustard that can be found in the domestic market. Sensory evaluation was conducted with the descriptive analytical method, system of scoring. The results were statistically analyzed. All samples were analyzed by physico-chemical analyses, microbiological analyses, physical-chemical analyses of contaminants (the contents of pesticide residues, heavy metals and mycotoxins) and energy value of the sample. All results showed that the samples of four kinds of mustard were in accordance with the Regulation on quality and other requirements for mustard, Regulation on the quality and conditions of usage of additives in food and the other requirements for additives and their mixtures, Regulation on microbiological food safety in the market and Regulation on the amount of pesticides, metals and metalloids and other toxic substances, chemotherapeutics, anabolics and other substances which can be found in food. The purpose of the experiment was investigation of sinalbin degradation products in produced mild yellow mustard paste. The samples were extracted in a Soxhlet extraction system and analyzed by gas chromatography - mass spectrometry (GC-MS) techniques. The results were compared with the analysis of the ground white mustard seeds which were dominant fatty acids, originally present in the white mustard seeds, are also present in the mustard paste condiment made from this plant. The most abundant sinalbin degradation product in yellow mustard paste was 4-(hydroxymethyl)phenol. Other compounds identified in this sample were: 4-methyl phenol, 4-ethyl phenol, 4-(2-hydroxyethyl)phenol and 2-(4-hydroxyphenyl) ethanoic acid..

Sinalbin degradation products in mild yellow mustard paste

Sinalbin degradation products in mild yellow mustard paste were investigated. The analyzed material consisted of a mild yellow mustard paste condiment and ground white mustard seeds which were originally used in the mustard paste production process. The samples were extracted in a Soxhlet extraction system and analyzed by gas chromatography - mass spectrometry (GC-MS) technique. The only sinalbin degradation product in ground mustard seeds was 2-(4-hydroxyphenyl)acetonitrile. The most abundant sinalbin degradation product in yellow mustard paste was 4-(hydroxymethyl)phenol. Other compounds identified in this sample were: 4-methyl phenol, 4-ethyl phenol, 4-(2-hydroxyethyl)phenol and 2-(4-hydroxyphenyl) ethanoic acid

Kinetika sušenja malina u laboratorijskim uslovima

For a long time Serbia has been an important producer, processor and exporter of the raspberry. From the point of view of primary production, we could be proud of our success. However, on the question of processing, we are somehow behind. The reason is the typical "line of least resistance". We have always earned enough by exporting frozen raspberry and no one has even tried to explore new products or other attractive useful values of this fruit. Namely, although the raspberry has attractive useful values (which brings high demand), it is known that it has some inviolable chemical engineering characteristics. The raspberry, due to its consistency, is very susceptible to mechanical damage. It is also known for its high breathing warmth, and therefore it can only be preserved for a short time. These characteristics impose upon the producers the necessity to quickly proceed with the conservation and processing. The best way to achieve the turnover of capital is by not processing it completely. When the raspberry is half-processed, investments are smaller and so are risks for the deterioration of the quality of the product. Among products not completely processed, made from raspberries and other types of fruits, the most convenient are certainly frozen or dried fruits. Unfortunately, up to now, little has been done on the drying process of the raspberry because the fruit is very perishable as a raw material and also various problems occur during the drying process. Positive results have, however, been achieved locally in the process of drying by freezing, i.e. lyophilizing. The subject of this paper is the kinetics of drying raspberry in laboratory conditions with the idea of pinpointing at which level of humidity there is a change in the speed of evaporation. The quantity of evaporated water is expressed in relative and absolute units of measure.Već dosta dugo Srbija je značajan proizvođač, prerađivač i izvoznik maline. Sa stanovišta primarne proizvodnje možda se može i pohvaliti, čak i ponositi dobrim uspesima. Ipak, sa stanovišta prerade nekako zaostajemo. Razlog je klasična "linija manjeg otpora". Uvek se dovoljno dobro zarađivalo izvozom smrznute maline i niko nije ni pokušavao da istražuje nove proizvode i neke druge atraktivne upotrebne vrednosti od ovog voća. Naime, iako malina ima atraktivnu upotrebnu vrednost (time i značajnu potražnju), poznato je da ima veoma nepovoljna tehnološka svojstva. Malina ima zbirnu cvast, a time i zbirni plod te je veoma osetljiva na mehanička oštećenja. Poznata je i po velikoj brzini tj. po visokoj toploti disanja, te stoga ima kratak period mogućeg čuvanja. Takva svojstva zahtevaju od proizvođača da veoma brzo reaguju sa konzervisanjem ili preradom. Najbrži obrt uloženog kapitala se može postići ako se od plodova dobiju poluproizvodi. Tada su ulaganja najmanja, a smanjen je i rizik po kvalitet. Među poluprerađenim proizvodima od maline, ali i ostalih vrsti voća. svakako su najpoželjniji zamrznuti ili osušeni plodovi. Nažalost, do sada se malo radilo na sušenju maline jer je ona veoma osetljiva kao sirovina i problemi pri sušenju su višestruki. Doduše, postoje i u domaćoj praksi pozitivni rezultati za sušenje smrzavanjem tj. liofilizacijom. U ovom radu je izučavana kinetika sušenja malina u laboratorijskoj sušari sa idejom da se uoči pri kojim sadržajima vlage dolazi do promene brzine isparavanja. Količina isparene vode je izražena u relativnim i apsolutnim jedinicama mere

Chemical composition of organically and conventionally grown fruits of raspberry (Rubus idaeus L.) cv. Willamette

The paper presents two-year results of chemical tests of raspberry fruits in organic and conventional cultivation systems. Raspberry plantations were established on the slopes of Jelica Mountain, on soil having very acidic reaction (pH/KCl 3.67–3.76) and optimal contents of humus and total N. In the conventional cultivation system, the soil had a high supply of readily available P2O5 and K2O and microelements, with excessive levels of Ni, and Cr. In the organic system, the content of Ni and Zn increased. The biochemical properties of organic and conventional fruits showed no significant differences, while the influence of the research year and the interaction of the cultivation system showed significant differences in the content of TA and IS. However, higher values of the levels of soluble solids, total acids and sugars contributed to the more appealing taste and aroma of organic raspberry fruits. The contents of microelements and heavy metals in the fruits of both cultivation systems were measured in the following order Mn>Fe>Zn>Cu>Ni>Cr>Co. No significant difference was found in the contents of the examined elements between organic and conventional fruits, except for the statistically higher content of Fe in organic raspberries. The high share of individual elements (especially Ni) in both cultivation systems indicates the need for continuous chemical testing of soil and fruits. Based on the results, it is important to consider the daily intake of each element in relation to body weight and/or maximum daily intake.Publishe

Parametri kvaliteta suncokretovog ulja i palminog oleina tokom višestrukog prženja

The refined sunflower and palm oils are used in the food industry for the production of fried potatoes. Literary data have shown that palm oil had less tendency to degradation than sunflower oil due to its fatty acid composition. However, palm olein is a palm oil fraction and therefore has a different composition of fatty acids. The aim of this study was to investigate the quality of the refined palm olein in relation to the refined linoleic type sunflower oil during the production of fried potatoes. The oil samples were used for multiple frying during the seven days (40 minutes per day at a temperature of 165o C). The peroxide value and free fatty acid content (acid value) were determined by standard analytical methods. The results showed that the peroxide value in sunflower oil and palm olein increased by 75.0% and 77.8%, while the acid value increased by 50.0% and 26.8%, respectively, in relation to their initial values in the fresh oil samples. Based on these results, it can be concluded that the palm olein was more suitable for frying. However, this finding cannot be reported with certainty because the quality of the oil depends on many more parameters, not only on those analysed in this paper.U prehrambenoj industriji se za proizvodnju prženog krompira koriste rafinisano suncokretovo i palmino ulje. Prema literaturnim podacima, palmino ulje ima manju sklonost ka degradacionim promenama u odnosu na suncokretovo ulje, zahvaljujući sastavu masnih kiselina. Međutim, palmin olein je frakcija palminog ulja i samim tim ima drugačiji sastav masnih kiselina. Cilj ovog rada bio je da se ispita kvalitet rafinisanog palminog oleina u odnosu na rafinisano suncokretovo ulje tokom proizvodnje prženog krompira. Uzorci ulja su korišćeni za višestruko prženje tokom sedam dana (po 40 minuta svakog dana, na temperaturi od 165o C). Peroksidni broj i sadržaj slobodnih masnih kiselina (kiselinski broj) određeni su standardnim analitičkim metodama. Rezultati su pokazali da se peroksidni broj u suncokretovom ulju i palminom oleinu povećao 75,0% odnosno 77,8%, dok se kiselinski broj povećao 50,0% odnosno 26,8%, u odnosu na početne vrednosti u uzorcima svežeg ulja. Na osnovu ovih rezultata može se zaključiti da je palmin olein pogodniji za prženje. Međutim, ovaj zaključak se ne može navesti sa sigurnošću jer kvalitet ulja zavisi od mnogo više parametara, a ne samo od onih analiziranih u ovom radu

Assessment of Chemical and Antioxidant Properties of Fresh and Dried Rosehip (Rosa canina L.)

This work aimed to evaluate the nutritional and functional properties of rosehip from Serbia. In respect to that, the content of twenty-three elements in the rosehip along with the soil were determined by inductively coupled plasma-optical emission spectroscopy and the bioaccumulation factor (BAF) was calculated. The total dry matter, water activity, and the contents of vitamin C, total phenolics and flavonoids were determined. The antioxidant ability of fresh and dried samples was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. The obtained extracts were analyzed by gas chromatography with flame ionization detection and gas chromatography - mass spectrometry techniques. In addition, assessment of the impact of thermal treatment on the chemical composition of rosehip was observed. The study revealed that the most abundant elements in rosehip were K, Ca, Mg, P and S with 2963.0, 1820.0, 709.0, 495.0 and 289.8 mg/kg, respectively. The highest BAF values in the system rosehip/soil were for S, K and P. Contents of ascorbic acid, total phenolics, total flavonoids and the antioxidant activity were reduced after the drying process by 56.3%, 20.4%, 31.3%, 21.9%, respectively. Nevertheless, dried rosehip was still a rich source of bioactive compounds with significant antioxidant activity. The presented results support traditional use of rosehip as food with health and nutritional benefits

Preliminarno ispitivanje sastava masnih kiselina u semenkama šipurka: primena ultrazvučne ekstrakcije

Rosehip seeds represent waste material which is obtained duringthe production of jams, marmalades, juices, teas, etc. Two methods were used forthe extraction of fatty acids from rosehip seeds: ultrasound-assisted extractioncombined with organic solvent extraction (UAE/OSCE) and organic solventconventional extraction (OSCE). Different solvent-to-sample ratio was used. Theidentification and quantitation of fatty acids was done by gas chromatography witha flame ionization detector (GC/FID). Applied methods yielded different types offatty acids, with stearic acid and linoleic acid, as the most abundant ones.Semenke šipurka predstavljaju otpadni materijal, bogat uljem, koji nastaje tokom proizvodnje džemova, marmelada, sokova, čajeva itd. Za ekstrakciju masnih kiselina iz semenki šipurka korišćene su dve metode: ultrazvučna ekstrakcija u kombinaciji sa ekstrakcijom organskim rastvaračem (UZE/KEOR)i konvencionalna ekstrakcija organskim rastvaračem (KEOR). Korišćeni su različiti odnosi zapremine rastvarača i mase uzoraka. Identifikacija i kvantifikacija masnih kiselina izvršena je metodom gasne hromatografije sa plameno-jonizujućim detektorom (GC/FID). Primenjenim ekstrakcionim metodama dobijene su različite masne kiseline, od kojih su stearinska i linolna bile najzastupljenije

Stabilnost vitamina C u proizvodima od šipurka (Rosa canina L.) i mogućnost valorizacije ulja iz semenki ploda

The fruits of rose hip (Rosa canina L.) are mainly used for the production of spreads (marmalade) and dried fruits for making tea. In this paper, a certain amount of fruit is dried in the laboratory dehydrator (air temperature of 60 °C for a period of 16 h, then air temperature of 50 °C for a period of 20 h) and on the other side marmalade is made in a traditional way from the remaining amount, with the idea to determine the stability of vitamin C after different heat treatments. Byproduct in the production of marmalade is a large amount of rose hip seeds which is a rich source of oil. The aim of this paper was to determine the content of vitamin C in the products after heat treatment in relation to the content of vitamin C in fresh sample by indirect iodimetry method (iodometry). The content of rose hip seed oil was determined by Soxhlet extraction and also the water activity of all samples. The results showed loses 17.54% (54.06% on a dry basis) of vitamin C during drying in the laboratory dehydrator and in the production of marmalade the loses were 73.68% (81.38% on a dry basis) of the vitamin C in relation to the initial content of the fresh sample. Water activity of the fresh sample was 0.92, of the marmalade was 0.72 and of dried rose hip was 0.60. The oil content in rose hip seeds was 9.2 % on a dry basis.Plodovi šipurka (Rosa canina L.) se najviše koriste za proizvodnju namaza (marmelada), a osušeni za spravljanje čajeva. U ovom radu, određena količina plodova je sušena u laboratorijskom dehidratoru (temperatura vazduha od 60 °C u trajanju od 16 h, potom temperatura vazduha od 50 °C u trajanju od 20 h), a od druge količine je napravljena marmelada na tradicionalan način sa idejom da se utvrdi stabilnost vitamina C nakon različitih načina termičke obrade. Nusprodukt pri proizvodnji marmelade je velika količina semenki šipurka koje su bogat izvor ulja. Cilj ovog rada je da se metodom indirektne jodimetrije (jodometrije) utvrdi sadržaj vitamina C u proizvodima nakon termičke obrade u odnosu na sadržaj vitamina C u svežem uzorku. Takođe, određeni su sadržaj ulja u semenkama šipurka ekstrakcijom po Soxhlet-u kao i aktivnost vode u svim uzorcima. Rezultati su pokazali da se pri sušenju u laboratorijskom dehidratoru gubi 17,54% vitamina C u odnosu na početni sadržaj u svežem uzorku (54,06% računato na suvu materiju), a pri proizvodnji marmelade gubi se 73,68% ovog vitamina u odnosu na početni sadržaj u svežem uzorku (81,38% računato na suvu materiju). Aktivnost vode u svežem uzorku iznosila je 0,92, u marmeladi 0,72, a u osušenom šipurku 0,60. Sadržaj ulja u semenkama šipurka iznosio je 9,2% u odnosu na suvu materiju