Uticaj toplotnog tretmana na sadržaj tanina i antioksidativni efekat ekstrakta hrastovog žira quercus cerris

The results of investigation of the tannin content in the oak acorn kernel Quercus cerris, qualitative analysis of tannin and antioxidation effect of ethanol extracts of acorn on porcine lipid (prime steam lard) as a substrate are presented in this paper. Experiments were carried out on kernel samples of the domestic oak acorn, from the location Zaglavak, near by the town of Bajina Bašta. Tannin content was determined by spectrophotometric procedure using phosphorus Wolframic acid on wave length of 715 nm. Qualitative analysis of tannin included sediment and stain responses as well as tannoform test with formalaldehyde and HCl. Antioxidant effect of ethanol extracts was investigated on fat samples treated at the temperature of 600C in the dark (Schaaloven test). The rate of oxidation was determined by measuring Peroxide value (Pb) and TBA value. The investigated extracts were obtained based on drying of acorn kernel and extracts based on thermal treatment - dry frying of acorn kernel. The obtained results show that dried acorn kernel contains 11.69 % of tannin and thermally treated acorn kernel 8.55%. Qualitative analysis confirmed the presence of gallic acid (pyrogallic, hydrolysing) tannins based on positive general sediment and stain responses on tannins. Ethanol extracts demonstrate antioxidation traits on porcine lipids in trial conditions. Synergistic effect of citric acid with primary anti oxidant was not proved. Thermal treatment of acorn kernel does not reduce the antioxidation activity of extracts.U radu su prikazani rezultati ispitivanja sadržaja tanina u jezgru hrastovog žira Quercus cerris, kvalitativna analiza tanina i antioksidaciono dejstvo etanolnih ekstrakata žira na svinjsku mast (pripremljenu vlažnim postupkom) kao supstratu. Ogledi su vršeni na uzorcima jezgra hrastovog žira domaćeg porekla, sa lokaliteta Zaglavak, okolina Bajine Bašte. Sadržaj tanina određivan je spektrofotometrijskim postupkom sa fosforvolframovom kiselinom na talasnoj dužini od 715 nm. Kvalitativna analiza tanina obuhvatila je taložne i bojene reakcije kao i tanoformsku probu sa formaldehidom i HCl. Zaštitni efekat etanolnih ekstrakata ispitivan je na uzorcima masti koji su temperirani na 600C u mraku. Tok oksidacije masti praćen je određivanjem TBA vrednosti ekstincije na 532 nm i peroksidnog broja. Ispitivani ekstrakti su dobijeni na bazi osušenog jezgra žira i ekstrakata na bazi termički tretiranog - suvo prženog žira. Dobijeni rezultati pokazuju da osušeno jezgro hrastovog žira sadrži 11,69% tanina a termički tretirano 8,55%. Kvalitativnim analizama dokazano je prisustvo galnih (pirogalnih hidrolizujućih) tanina na osnovu pozitivnih opštih taložnih i bojenih reakcija na tanine. Etanolni ekstrakti ispoljavaju antioksidaciona svojstva na svinjsku mast pri uslovima ogleda, sinergistički efekat limunske kiseline sa primarnim antioksidantom nije dokazan, termički tretman jezgra hrastovog žira ne smanjuje antioksidacionu aktivnost ekstrakata

Neke fizičko-hemijske karakteristike ulja semena cera (Ouercus cerris L)

The results obtained from the investigations on oil extracted from Turkey oak seed (Quercus cerris L) are shown in this paper. Using standard JUS ISO methods, some physical and chemical parameters wich characterize oil quality were determined in the extracted oil. The values obtained are approximately equal to ones for oils of similar composition. The composition of fatty acids was determined using GLC method and the most represented of them, oleinic linolic and palmitic acids made 94,89 % of the total fatty acids. The content ofunsatu-rated and saturated fatty acids was 79,34 % and 20,66 % respectively. Regarding the content of fatty acids, Turkey oak seed oil is the most similar to avocado and peanut oil. Turkey oak seed oil is very interesting for the possible use in cosmetic and pharmaceutical industry.U radu su prikazani rezultati ispitivanja ulja ekstrahovanog iz semena cera (Quercus cerris L). U ekstrahovanom ulju su standardnim JUS ISO metodama određeni neki fizičko-hemijski parametri koji karakterišu kvalitet ulja. Utvrđene vrednosti su približno iste vrednostima ulja sličnog sastava. Metodom GLC je određen sastav masnih kiselina, od kojih najzastupljenije oleinska, linolna i palmitinska čine 94,89 % ukupnih masnih kiselina. Sadržaj nezasićenih masnih kiselina je 79,34 %, a zasićenih 20,66 %. U pogledu sastava masnih kiselina ulje semena cera je najsličnije avokadovom i ulju kikirikija. Ulje semena cera je interesantno sa aspekta moguće primene u kozmetičkoj i farmaceutskoj industriji

Influence of protective characteristics of packaging material on packed dried fruits

Dried fruits are very delicate to biochemical changes during storage, due to low water content, as well as low aw value. The shelf life of these products depends on aw value. Materials for dry fruits packaging are necessary to have appropriate barrier characteristics for water, oxygen, nitrogen and carbon dioxide molecules, as well as for electromagnetic rays, especially those with low wavelengths in UV region. During storage of packed dry fruits, qualitative changes, influenced by different packaging materials, may occur. The results of tested characteristics of different packaging materials, combination and their barrier features, as well as the qualitative changes of packaged dried apples are presented in this paper. The qualitative changes of color and sensory characteristics of packaged dried apples point out to influence of the type, combination as well as the barrier features of used packaging materials.