Promjene u sastavu masnih kiselina fosfolipida mozga i jetre štakora hranjenih nemasnom dijetom

This study has been undertaken with the aim of elucidating the effect of a fat-free diet (FFD), which is known to be deficient in essential fatty acids (EFA), on the composition of fatty acids in the brain and liver glycerophospholipids of rats. Changes in the stereochemical distribution of fatty acids linked to the sn-1 or sn-2 position were of special interest. Two groups of animals were fed either the control diet (CD) or the FFD for two weeks. From the total lipid extracts of the brain and liver tissues, phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol+phosphatidylserine (PI+PS) fractions were separated by column and thin layer chromatography (TLC). After digestion with phospholipase A2 (PLA2), fatty acids from the sn-1 and sn-2 positions were separately converted into methyl esters and analyzed by gas chromatography. In animals fed FFD, the relative levels of unsaturated fatty acids increased in the sn-1 position of the PI+PS fraction in both liver and brain tissues, as well as in the PE fraction from the brain tissue. In other fractions no statistically significant differences were found. When the levels of particular fatty acids were evaluated, significant decreases in the amounts of palmitic (PA, 16:0), stearic (SA, 18:0), and nervonic (NA, 24:1n-9) acids, and/or significant increases of eicosenoic (ENA, 20:1n-9), arachidonic (AA, 20:4n-6) and docosahexaenoic (DHA, 22:6n-3) acids were detected in some fractions. It can be concluded that in the brain and liver glycerophospholipids of rats fed FFD, the EFAs lacking in the diet were moderately substituted by endogenously synthesized unsaturated fatty acids.Ovo je istraživanje provedeno da bi se utvrdio učinak nemasne dijete, deficitarne esencijalnim masnim kiselinama, na sastav masnih kiselina glicerofosfolipida mozga i jetre štakora. Poseban je interes usmjeren na stereokemijsku raspodjelu masnih kiselina vezanih na sn-1 i sn-2 položaj. Životinje su podijeljene u dvije skupine i hranjene kontrolnom ili nemasnom dijetom tijekom dva tjedna. Primjenom kromatografije na koloni i tankoslojne kromatografije iz ekstrakta ukupnih lipida mozga i jetre izdvojene su ove frakcije: fosfatidilkolin (PC), fosfatidiletanolamin (PE) i fosfatidilinozitol+fosfatidilserin (PI+PS). Fosfolipidne su frakcije obrađene fosfolipazom A2 i masne kiseline s položaja sn-1 i sn-2 odvojeno prevedene u metilne estere i analizirane plinskom kromatografijom. Kod životinja hranjenih nemasnom dijetom utvrđeno je povećanje udjela nezasićenih masnih kiselina na položaju sn-1 PI+PS frakcije jetre i mozga, te PE frakcije mozga. U ostalim frakcijama nisu nađene statistički značajne promjene omjera zasićenih i nezasićenih masnih kiselina. Analizom udjela pojedinih masnih kiselina u nekim frakcijama utvrđeno je statistički značajno smanjenje udjela palmitinske (PA, 16:0), stearinske (SA, 18:0) i nervonske (NA, 24:1n-9) kiseline i/ili značajno povećanje udjela eikozaenske (ENA, 20:1n-9), arahidonske (AA, 20:4n-6) i dokozaheksaenske (DHA, 22:6n-3) kiseline. Zaključeno je da se u glicerolipidima mozga i jetre štakora hranjenih nemasnom dijetom nedostatak esencijalnih masnih kiselina djelomično nadoknađuje endogenom sintezom nezasićenih masnih kiselina

Senzorska svojstva i kemijski sastav Šarskog sira s Kosova

Food sensory properties, analyses and chemical composition are very important because they provide information about product quality and end-user acceptance or preferences. An assessment of sensory characteristics and chemical composition of mountain sheep and cow’s-milk cheese from shepherd’s huts and industrial manufacturers in Kosovo was carried out. Consumer-oriented tests using a 9 point hedonic scale were conducted in order to determine Sharri cheese acceptability. Chemical parameters (fat content, fat content of dry matter, acidity, protein, dry matter, mineral and water content and sodium chloride content) of 45-day brine cheese samples were also analyzed. Chemical and sensory assessment demonstrated large property differences. A recommendation stems from the results showing that the standardization of both artisanal and industrial production of Sharri cheese is required.Senzorska svojstva i kemijski sastav hrane vrlo su značajni jer pružaju informaciju o kvaliteti proizvoda te o njegovoj prihvatljivosti za krajnjeg korisnika. Provedena je procjena senzorskih karakteristika i kemijskog sastava planinskog sira od ovčjeg i kravljeg mlijeka pastirskih gospodarstava i od industrijskih proizvođača s Kosova. Testiranje potrošača provedeno je hedonističkom ljestvicom s 9 bodova kako bi se utvrdila prihvatljivost Šarskog sira. Također su analizirani kemijski pokazatelji (udio masti, udio masnoća u suhoj tvari, kiselost, proteini, mineralne tvari, te količina vode i natrija) u uzorcima sira u salamuri, pohranjenog 45 dana. Kemijska analiza i senzorska procjena pokazale su velike razlike u svojstvima, što ukazuje na potrebu da se standardizira proizvodnja Šarskog sira, kako u zanatskim tako i u industrijskim uvjetima

Fatty acid composition of human milk and infant formulas

Odgovarajući sastav masnih kiselina membranskih lipida nužan je za izgradnju i funkciju nervnog sustava u razvoju. Intenzivna sinteza moždanog tkiva odvija se u posljednjem trimestru trudnoće i u prvim tjednima nakon rođenja. Ova sinteza moždanih struktura uključuje sintezu složenih lipida, od kojih mnogi u značajnoj mjeri sadrže esencijalne masne kiseline i njihove više homologe. Zadaća ovog rada bila je istražiti u kojoj mjeri sastav masnih kiselina ponuđene dječje hrane zadovoljava potrebe za esencijalnim masnim kiselinama. Ukupni lipidi iz uzoraka mlijeka dojilja i iz pripravaka dječje hrane ekstrahirani su smjesom otapala kloroform : metanol. Nakon pripreme metilnih estera, sastav masnih kiselina određen je plinskom kromatografijom. Posebna pažnja usmjerena je na sadržaj dugolančanih polinezasićenih masnih kiselina. Rezultati pokazuju da većina pripravaka dječje hrane, namijenjenih supstituciji majčinog mlijeka, sadrži srednjelančane masne kiseline (C 10:0, C 12:0) kao i ostale zasićene masne kiseline u količini dovoljnoj za energijske potrebe dojenčadi. Iako je linolna kiselina (C18:2, n-6) bila prisutna u omjeru koji bi trebao zadovoljiti potrebe za esencijalnim masnim kiselinama, većina preparata nije sadržavala dovoljne količine dugolančanih polinezasićenih masnih kiselina neophodnih za nesmetani razvoj mozga, unatoč stalnim preporukama da ove kiseline treba koristiti kao dodatak hrani za dojenčad.The appropriate fatty acid composition of membrane lipids is necessary for structure and function of the developing nervous system. Rapid synthesis of brain tissue occurs during the last trimester of pregnancy and the early postnatal weeks. This synthesis of brain structure involves the formation of complex lipids, many of which contain significant quantities of essential fatty acids and their higher homologs. This study was undertaken to elucidate how fatty acid compositions of available diets for infants meet the requirements for essential fatty acids. Samples of infant formulas, present on the market, as well as milk samples obtained from breast feeding mothers, were extracted by chloroform : methanol mixtures in order to obtain total lipids. Fatty acid methyl esters were prepared and fatty acid composition was revealed by gas chromatography. Special interest was directed to the content of long chain polyunsaturated fatty acids. The results have shown that infant formulas, designed to substitute mothers’ breast milk, contain medium chain fatty acids (C 10:0, C 12:0), along with the other saturated fatty acids, in the amounts acceptable for infants’ energy consumption. Although linoleic acid (C18:2, n-6) was present at the level expected to cover needs for essential fatty acids, most of the tested products did not contain sufficient amounts of long chain polyunsaturated fatty acids, despite the fact that these fatty acids are necessary for undisturbed brain development, ignoring the strong recommendations that they should be used as a supplement in infants’ food

The effect of fungal competition on colonization of soybeans by moulds of the genus Aspergillus, Trichothecium and Fusarium and the ochratoxin A accumulation as related to temperature and moisture content

The relationship between mould biomass and accumulation of ochratoxin A (OTA) on solid substrate (slightly cracked soybeans) at temperatures from 15 to 35°C and a water content in the substrate of 20 to 38% was been investigated. The experiments were carried out with the mould Aspergillus ochraceus NRRL 3174 in pure culture and in mixed culture, respectively; the latter with the moulds Trichothecium roseum ZMPBF 1226 and Fusarium graminearum ZMPBF 1244. The biomass growth during cultivation was monitored by measuring the analysis of chitin as glucosamine, and the concentration of OTA was measured by high performance liquid chromatography (HPLC) method using Hewlett-Packard instrument with fluorescence detector. It was established that the accumulation of the examined OTA primarily depend on the temperature of cultivation rather than on the growth of the biomass. Thebiomass of the mixed culture of A. ochraceus, T. roseum and F. graminearum after 35 days of cultivation reduced the amount of OTA by 48, 72 and 85%, respectively. The decrease of concentration of OTA is more pronounced in the substrate with a higher initial water content and at higher temperature of cultivation.Keywords: Moulds, mycotoxins, ochratoxin A, chitin, HPL

Adhesion of Zearalenone to the Surface of Lactic Acid Bacteria Cells

Zearalenone is mycotoxin harmful to the health of humans and animals and is present in food and feed. Therefore, last few decades, great attention is paid to the development of biological detoxification methods with reference to the application of lactic acid bacteria in binding and removal of mycotoxins from food and feed. The aim of this work was to investigate the ability of lactic acid bacteria Lactobacillus rhamnosus GG (ATCC 53103) and Lactobacillus plantarum A1 to bind zearalenone unto the cell surface. The results showed that Lactobacillus rhamnosus GG (ATCC 53103) and Lactobacillus plantarum A1 can bind signifi cant concentration of zearalenone, depending on the bacteria concentration in the medium and the incubation time. However, with longer time of incubation part of bounded mycotoxins were released back into the medium which indicates that the reaction of adhesion of toxin to the bacterial cells is reversible. Determination of zearalenone concentration was performed by competitive ELISA test

Listeria monocytogenes and other contaminants in fresh cheese and cream from Zagreb city area domestic production

Svrha ovog rada bila je odrediti udovoljavaju li svježi sir i vrhnje koji se proizvode na tradicionalan način u kućanstvu i slobodno prodaju na zagrebačkim tržnicama mikrobiološkim standardima za namirnice (NN 46/94, 20/01, 40/01). Posebna pažnja posvećena je istraživanju prisutnosti bakterije Listeria monocytogenes u navedenim namirnicama, zbog njezine izrazite opasnosti po ljudsko zdravlje. Od ukupno 120 istraživanih uzoraka mliječnih proizvoda, većina - 64 (53 %) bila je kontaminirana patogenim mikroorganizmima, od čega 16 % otpada na svježi sir a 37 % na uzorke vrhnja. Čak 39 uzoraka sira i 50 uzoraka vrhnja nije udovoljilo uvjetima propisanim pravilnikom, primarno zbog kontaminacije kvascima i plijesnima. Od 10 uzoraka sira i vrhnja u kojima je dokazana L. monocytogenes klasičnim mikrobiološkim metodama, PCR-metodom u samo jednom uzorku potvrđena je L. monocytogenes, i to uzorku vrhnja.The purpose of this research was to determine whether the cream cheese and cream that are produced in the traditional manner at home and are free to sale on Zagreb markets, meet microbiological requirements for foodstuffs (OG 46/94, 20/01, 40/01). Particular attention is given to research of bacteria Listeria monocytogenes presence in these foods, because of its exceptional hazards to human health. It was found that a majority of 64 (53 %) from a total of 120 studied dairy products samples were contaminated with microbial pathogens, of which 16 % are waste in the cream cheese, and 37 % in cream samples. 39 samples of cheese and 50 samples of cream did not fulfil the conditions prescribed by the Croatian Guidelines, primarily due to the contamination with yeasts and moulds. In 10 cheese and cream samples where L. monocytogenes is proven by classical microbiological methods, PCR method confirmed L. monocytogenes in only one cream sample

Aflatoxin M1 in raw milk and binding of aflatoxin by lactic acid bacteria

Aflatoksin M1 (AFM1) potencijalni je karcinogen za ljude, te njegova prisutnost u mlijeku i mliječnim proizvodima predstavlja opasnost za ljudsko zdravlje. Stoga se u ovom radu određivao stupanj mikrobiološkog onečišćenja plijesnima te potencijalna prisutnost aflatoksina M1 u 60 uzoraka sirovog mlijeka, nasumično uzetih od individualnih proizvođača iz različitih krajeva kontinentalne Hrvatske. Najčešće izolirani rodovi plijesni bili su Geotrichum (78,3 %), Aspergillus (32,4 %) i Penicillium (27,0 %). Od ukupno 60 istraživanih uzoraka mlijeka u 86,66 % utvrđena je prisutnost aflatoksina M1, a u 6,66 % uzoraka količine su bile iznad dozvoljenih granica. Bakterije mliječne kiseline koje se koriste u proizvodnji fermentiranih mliječnih proizvoda kao starter kulture, mogu imati ulogu u smanjenju količine aflatoksina u hrani i krmivu. U ovom je radu istražena i sposobnost bakterija mliječne kiseline Lactobacillus rhamnosus GG (ATCC 53103), Lactobacillus delbrueckii S1 i Lactobacillus plantarum A1 da vežu aflatoksin M1. Standardni soj L. rhamnosus GG (ATCC 53103) i izolat L. delbrueckii S1 mogu značajno (P50%) u usporedbi s izolatom L. plantarum A1 koji ga može vezati između 18,7 do 28,7 %.Aflatoxin M1 (AFM1) is potential human carcinogen. Its presence in milk and dairy products represents risk for human health. Therefore, this study was carried out in order to determine thedegree of microbiological contamination by mold, and the potential presence of aflatoxin M1 in 60 raw milk samples, randomly taken from individual producers from different regions of the continental Croatia. The most common genera isolated fungi were Geotrichum (78.3 %), Aspergillus (32.4 %) and Penicillium (27.0 %). From total of 60 studied milk samples, 86.66 % were positive for the presence of aflatoxin M1, and 6.66 % of samples were above the prescribed limits. Lactic acid bacteria used in fermented dairy products as a starter culture may play a role in reduction of aflatoxin in foods and nutrients. In this paper the ability of lactic acid bacteria: Lactobacillus rhamnosus GG (ATCC 53103), Lactobacillus delbrueckii S1 and Lactobacillus plantarum A1 to bind aflatoxin M1 was investigated. Standard strain L. rhamnosus GG (ATCC 53103) and L. delbrueckii S1 can significantly (P50 %) compared to L. plantarum A1, which binds AFM1 between 18.7 to 28.7 %

Antifungal Effect of the Bacterium Lactobacillus plantarum K1 on Growth of Mold Aspergillus ochraceus ZMPBF 318

Većina namirnica i krmiva osjetljiva je na kontaminaciju plijesnima u različitim fazama proizvodnje, prerade, transporta i uskladištenja. Tako klimatski uvjeti i uvjeti prilikom procesa proizvodnje, transporta i uskladištenja mogu pospješiti porast plijesni, kao i sintezu mikotoksina. Suvremena proizvodnja zahtijeva što manju upotrebu kemijskih spojeva za očuvanje i zaštitu prehrambenih proizvoda i krmiva pa se koriste bakterije mliječne kiseline koje proizvode metabolite koji imaju antifungalni učinak, te sprečavaju kvarenje hrane i krmiva uzrokovano nepoželjnim vrstama plijesni. Stoga je u ovom radu istraživano antifungalno djelovanje izolata bakterije mliječne kiseline Lactobacillus plantarum K1 na rast plijesni Aspergillus ochraceus ZMPBF 318 u tekućoj hranjivoj podlozi (kvaščev ekstrakt) pri 28 °C tijekom 28 dana. Istraživanja rasta ove plijesni su provedena u podlozi uz dodatak supernatanta fermentirane hranjive podloge u kojoj je porasla bakterija Lactobacillus plantarum K1 i u prisutnosti suspenzije stanica ove bakterije. Rezultati su pokazali da suspenzija stanica bakterije Lactobacillus plantarum K1 značajno inhibira rast plijesni tijekom prvih 14 dana inkubacije, dok supernatant pokazuje dobar inhibitorni utjecaj na rast plijesni kroz duži period inkubacije.Most of the food and feed are contamination sensitive to molds in various stages of production, processing, transportation and storage. Thus, climate conditions and conditions during the production process, transport and storage can enhance the growth of molds and mycotoxin synthesis. Reduced utilization of chemical compounds added in order to preserve and protect food and animal feed is required in modern production. So, lactic acid bacteria which produce metabolites with antifungal effect and prevent spoilage of food and feed by undesirable molds have been used. Therefore, in this paper antifungal activity of isolate of lactic acid bacterium Lactobacillus plantarum K1 on the growth of mold Aspergillus ochraceus ZMPBF 318 in broth (yeast extract) at 28 °C for 28 days was investigated. Investigation of the growth of the mold was carried out in the broth with addition of supernatant of fermented broth in which bacterium Lactobacillus plantarum K1 grew and in the presence of the bacterial cell suspension. The results show that during fi rst 14 days of incubation the mold growth was significantly inhibited by cell suspension of bacterium Lactobacillus plantarum K1, while good inhibitory effect of the supernatant on the growth of the mold was obtained with longer incubation time

Aflatoxin M1 in raw milk and binding of aflatoxin by lactic acid bacteria

Aflatoksin M1 (AFM1) potencijalni je karcinogen za ljude, te njegova prisutnost u mlijeku i mliječnim proizvodima predstavlja opasnost za ljudsko zdravlje. Stoga se u ovom radu određivao stupanj mikrobiološkog onečišćenja plijesnima te potencijalna prisutnost aflatoksina M1 u 60 uzoraka sirovog mlijeka, nasumično uzetih od individualnih proizvođača iz različitih krajeva kontinentalne Hrvatske. Najčešće izolirani rodovi plijesni bili su Geotrichum (78,3 %), Aspergillus (32,4 %) i Penicillium (27,0 %). Od ukupno 60 istraživanih uzoraka mlijeka u 86,66 % utvrđena je prisutnost aflatoksina M1, a u 6,66 % uzoraka količine su bile iznad dozvoljenih granica. Bakterije mliječne kiseline koje se koriste u proizvodnji fermentiranih mliječnih proizvoda kao starter kulture, mogu imati ulogu u smanjenju količine aflatoksina u hrani i krmivu. U ovom je radu istražena i sposobnost bakterija mliječne kiseline Lactobacillus rhamnosus GG (ATCC 53103), Lactobacillus delbrueckii S1 i Lactobacillus plantarum A1 da vežu aflatoksin M1. Standardni soj L. rhamnosus GG (ATCC 53103) i izolat L. delbrueckii S1 mogu značajno (P50%) u usporedbi s izolatom L. plantarum A1 koji ga može vezati između 18,7 do 28,7 %.Aflatoxin M1 (AFM1) is potential human carcinogen. Its presence in milk and dairy products represents risk for human health. Therefore, this study was carried out in order to determine thedegree of microbiological contamination by mold, and the potential presence of aflatoxin M1 in 60 raw milk samples, randomly taken from individual producers from different regions of the continental Croatia. The most common genera isolated fungi were Geotrichum (78.3 %), Aspergillus (32.4 %) and Penicillium (27.0 %). From total of 60 studied milk samples, 86.66 % were positive for the presence of aflatoxin M1, and 6.66 % of samples were above the prescribed limits. Lactic acid bacteria used in fermented dairy products as a starter culture may play a role in reduction of aflatoxin in foods and nutrients. In this paper the ability of lactic acid bacteria: Lactobacillus rhamnosus GG (ATCC 53103), Lactobacillus delbrueckii S1 and Lactobacillus plantarum A1 to bind aflatoxin M1 was investigated. Standard strain L. rhamnosus GG (ATCC 53103) and L. delbrueckii S1 can significantly (P50 %) compared to L. plantarum A1, which binds AFM1 between 18.7 to 28.7 %

The Effect of Experimental Fungal Emulation on Colonization of Soybeans by Moulds of the Genus Aspergillus and Fusarium and on Aflatoxin B1 Accumulation in Relation to Temperature and Moisture Content in vitro

One strain of Aspergillus flavus ATCC 26949 and one strain of Fusarium graminearum ZMPBF 1244 were used to investigate the effect of growth in mixed culture on aflatoxin B1 (AFB1) accumulation in respect to time and temperature of cultivation in vitro. The experiments were carried out with aflatoxigenous mould A. flavus ATCC 26949 in pure culture and in mixed culture, respectively, the latter with the common mould F. graminearum ZMPBF 1244. F. graminearum does not produce aflatoxins and chromatographycally similar compounds. The amount of biomass was estimated by measuring the chitin content; the aflatoxin accumulation by means of UV light and ELISA method. It was established that the accumulation of AFB1 primarily depend on the temperature of cultivation, rather than on growth of the mycelium. The biomass of the mixed culture of A. flavus and F. graminearum after 35 days of cultivation reduces the amount of AFB1 by 55 to 76% in respect to highest values obtained in experiments with the pure culture of A. flavus. Decrease of this toxin amount is more pronounced in the substrate at the higher water content and at the higher temperature of cultivation. As a general rule, cultures grown in mixed culture under investigate temperature conditions produced less amount of AFB1 than A. flavus grown in pure culture