The Influence of Milk Type on the Proteolysis and Antioxidant Capacity of White-Brined Cheese Manufactured from High-Heat-Treated Milk Pretreated with Chymosin

We investigated the effect of milk type on the proteolysis and total antioxidant capacity (TEAC) of white-brined cheeses prepared from high-heat-treated (90 degrees C, 10 min) cow's and goat's milk, pretreated with chymosin at a low temperature (4 degrees C). The cheeses produced showed improved antioxidant characteristics and a high content of denatured whey proteins. However, these characteristics depend on the type of milk and the ripening time. Ripened cow's milk cheese had higher values of WSN/TN (water-soluble nitrogen per total nitrogen content) and TCA-SN/TN (nitrogen soluble in 12% trichloroacetic acid per total nitrogen), but similar PTA-SN/TN (nitrogen soluble in 5% phosphotungstic acid per total nitrogen) values were observed in ripened cheeses. The antioxidant potential of a WSF (water-soluble fraction) was higher in goat's milk cheese, but higher TEAC (total antioxidant capacity) values of WINF (water-insoluble fraction) were observed in matured cow's milk cheese. In vitro digestion slightly improved the radical scavenging capacity of WSF, whereas digested WINF had more than twice the capacity of their undigested counterparts. The cheeses prepared in this study could be a good source of antioxidant peptides. Further investigations of their in vitro and in vivo functionality need to be conducted

IN VITRO ANTIOXIDANT POTENTIAL OF SOYBEAN HULL EXTRACTS

Hull is the major by-product of soybean processing industry. Generally, it is regarded as „waste“ and used for animal feeding or discarded directly causing resource wastage and environmental pressure. However, soy hull can be a good source of bioactive compounds including isoflavones and other polyphenols, trypsin inhibitors and bioactive peptides. Most of these compounds are associated with antioxidant activity and it is believed that they can contribute to the reduction of oxidative stress, which is associated with the occurrence of a number of degenerative diseases. In this study we investigated in vitro antioxidant properties (ABTS radical scavenging activity, reducing power and iron (II) chelating ability), as well as total phenolic, flavonoid and dihydroxycinnamic acid derivates contents of water and methanol extracts of soybean hulls. For these purpose deffated commercial soy hulls were thermally pre-treated for 10 minutes using steam at 1.3 bars (wet heating) in oven at 120 ºC (dry heat treatment) during the same period. According to the results of this study both, thermal pre-treatment and extraction agent affect in vitro antioxidant potential, total content of phenolic and flavonoid compounds as well as the content of dihydroxycinnamic acid derivates. Water extracts had more than twice higher ABTS radical scavenging activity (4.57-4.91 mgETrolox/g) than the methanol extracts (2.03-2.16 mgETrolox/g), but similar Fe (II) chelating ability. Water extracts are characterized with higher content of total phenols, flavonoids and dihydroxycinnamic acid derivates compared to methanol extracts

Utjecaj zrenja u salamuri i pod vakuumom na udjele proteina, masnih kiselina i mineralnih tvari te antioksidacijski potencijal bijelog sira s manjim udjelom mliječne masti

Research background. Numerous factors affect the ripening of reduced-fat white cheese. The aim of this study is to investigate the influence of ripening environment (brine or vacuum plastic bags without brine) on the chemical composition, protein, fatty acid profile and mineral content as well as antioxidant properties of industrially produced reduced-fat white cheese. Experimental approach. A low-fat white cheese was manufactured on an industrial scale from milk that remained after the production of kajmak and ripened for 60 days at 4 °C after packaging in a polystyrene container with brine containing 6% salt or in vacuum-sealed polyethylene bags. The influence of ripening environment on proteolysis was monitored by the change of soluble nitrogen fractions as well as by sodium dodecyl sulphate–polyacrylamide gel electrophoresis of tris(hydroxymethyl) aminomethane-HCl extracts of cheese proteins under non-reducing conditions and water-soluble fractions under reducing conditions. An effect that ripening environment had on fatty acid and mineral content was also monitored. The change of antioxidant potential of the investigated cheese during ripening led to the change of iron(II) chelating ability, reducing power and free-radical scavenging activity. Results and conclusions. The ripening environment differently affected proteolysis, fatty acid composition, mineral profile and antioxidant properties of reduced-fat white cheese. White cheese ripened in brine had more intensive proteolytic changes than the cheese ripened in a vacuum, but also more intensive diffusion processes, especially between the 40th and 60th day of ripening. The brine-ripened cheese had higher values of water-soluble nitrogen content, but lower contents of trichloroacetic acid-soluble and phosphotungstic acid-soluble nitrogen than the vacuum-ripened cheese. Cheese ripened in brine had a lower content of almost all investigated macro- and microelements. After 60 days of ripening, in cheese ripened in brine only myristic (C14:0) and palmitic acid (C16:0) were detected, whereas in the vacuum-ripened cheese C10:0-C16:0 fatty acids dominated. Vacuum-ripened reduced-fat cheese had more favourable reducing power, while white brined reduced-fat cheese had better radical scavenging activity and iron(II) chelating activity. Novelty and scientific contribution. These results suggest significant influence of ripening conditions (immersion in brine or in vacuum-sealed polyethylene bags) on nutritive and functional properties of reduced-fat white cheese. Ripening in a vacuum has become a useful method for obtaining high-value reduced-fat white cheese.Pozadina istraživanja. Brojni faktori utječu na zrenje bijelog sira s manjim udjelom mliječne masti. Svrha je ovog istraživanja bila ispitati utjecaj uvjeta u kojima se odvija zrenje (u salamuri ili plastičnoj vakumiranoj vrećici bez salamure) na kemijski sastav, udjele proteina, masnih kiselina i mineralnih tvari te antioksidacijska svojstva industrijski proizvedenog bijelog sira s manjim udjelom mliječne masti. Eksperimentalni pristup. Bijeli sir s malim udjelom mliječne masti proizveden je u industrijskim mjerilima iz mlijeka preostalog nakon proizvodnje kajmaka, te je nakon pakiranja sazrijevao tijekom 60 dana na temperaturi od 4 °C u polistirenskim kutijama sa salamurom koja sadržava 6 % soli ili u vakumiranim polietilenskim vrećicama. Ispitan je utjecaj uvjeta zrenja na proteolizu, i to praćenjem promjene udjela topljivih dušikovih frakcija te SDS–poliakrilamid gel elektroforezom ekstrakata proteina sira dobivenih pomoću Tris(hidroksimetil)aminometana i HCl u nereducirajućim uvjetima te frakcija topljivih u vodi u reducirajućim uvjetima. Također je praćen utjecaj uvjeta zrenja na udjele masnih kiselina i mineralnih tvari. Promjena antioksidacijskog potencijala ispitanih uzoraka sira tijekom zrenja uzrokovala je promjenu svojstva keliranja Fe(II) iona, redukcijske snage i sposobnosti hvatanja slobodnih radikala. Rezultati i zaključci. Uvjeti u kojima je sazrijevao bijeli sir s manjim udjelom mliječne masti različito su utjecali na proteolizu, udjele masnih kiselina i mineralnih tvari te antioksidativna svojstva sira. U bijelom siru koji je sazrijevao u salamuri zamijećene su intenzivnije proteolitičke promjene, te su u njemu difuzijski procesi bili intenzivniji od onih u siru koji je sazrijevao pod vakuumom, naročito između četrdesetog i šezdesetog dana zrenja. Sir koji je sazrijevao u salamuri imao je veći udjel dušikovih spojeva topljivih u vodi, ali manji udjel dušikovih spojeva topljivih u trikloroctenoj i fosfovolframovoj kiselini. Sir koji je sazrijevao u salamuri imao je manji udjel skoro svih ispitanih makro- i mikroelemenata. Nakon 60 dana zrenja, u siru koji je sazrijevao u salamuri pronađene su samo miristinska (C14:0) i palmitinska kiselina (C16:0), dok su u siru koji je sazrijevao u vakuumu prevladavale C10:0-C16:0 masne kiseline. Sir s manjim udjelom mliječne masti koji je sazrijevao pod vakuumom imao je bolje reducirajuće svojstvo, dok je sir koji je sazrijevao u salamuri imao veću sposobnost hvatanja slobodnih radikala i veću moć keliranja Fe(II) iona. Novina i znanstveni doprinos. Ovi rezultati pokazuju bitan utjecaj uvjeta zrenja (u salamuri ili pod vakuumom) na hranjiva i funkcionalna svojstva bijelih sireva s manjim udjelom mliječne masti. Zrenje pod vakuumom se sve više smatra korisnom metodom dobivanja visokovrijednih bijelih sireva s manjim udjelom mliječne masti

[The effect of in vitro digestion on antioxidant properties of water-soluble and insoluble protein fractions of traditional serbian white-brined cheeses] [Utjecaj in vitro digestije na antioksidativna svojstva u vodi topljivih i netopljivih proteinskih frakcija tradicionalnih srpskih bijelih sireva u salamuri]

The influence of simulated in vitro digestion on antioxidant potential of protein fractions of traditional Serbian white-brined cheeses was investigated. Water-soluble (WSF) and water-insoluble fractions (WINF) of three cow’s and three ovine white-brined cheeses were fractionated. Total antioxidant capac-ity, reducing power and iron (II) chelating properties of these fractions before and after in vitro digestion were assayed. The investigated protein fractions had different antioxidant properties. WSFs had a better total antioxidant capacity and reducing power and less pronounced iron (II) chelating properties than WINFs. A strong negative correlation (-0.818, P<0.05) between the total antioxidant capacities of undigested WSF and WINF of traditional cheeses were observed. In vitro digestion greatly improved the total antioxidant capacities of WINFs (by 16.61-34.18 times), their reducing power (up to 95.77 %) and except in the case of Svrljig ovine cheese, the iron (II) chelating ability as well. A less pronounced increase (up to 71.29 %) of the total antioxidant capacity of WSFs was induced by in vitro digestion. In vitro digestion reduced reducing power of WSF of investigated ovine cheeses as well as reducing power of WSF of Homolje cow’s cheese. Since there was no significant correlation between the investigated antioxidant properties of digested WSFs and their free amino acids and mineral contents the observed differences should be attributed to different composition and properties of low molecular weight pep-tides. Thus, further investigations related to their isolation and characterization needs to be conducted. However, these results indicate that Serbian white-brined cheeses have great potential as source of antioxidant peptides

Proteinski, masno-kiselinski i mineralni profili te antioksidacijski kapacitet Kupreškog sira u različitim fazama zrenja

Kupres cheese is a traditional Bosnian full-fat hard cheese. This paper deals with the change of protein and fatty acid profiles, mineral content and antioxidant potential during the period of three months of its ripening. Proteolysis was monitored by the electrophoresis of total extracts and water-soluble fractions under reducing conditions, whereas fatty acid profiles were determined by gas chromatography. The mineral content in the ripened cheeses was determined by using methods of Inductively coupled plasma - optical emission spectrometry (ICP-OES) for microelements and Inductively coupled plasma mass spectrometry (ICP-MS) for microelements, respectively. Ripening of Kupres cheese during three months is characterised by a relatively slow proteolysis, especially during the first month and by the increase in desirable fatty acid content. After 30 days of ripening, the WSN/TN and TCA/TN contents increased from 8.23% and 2.25% to 10.15% and 3.59%, respectively. Further, ripening induced higher increase of these parameters and more intensive degradation of the major caseins, especially αs-CN. After three months of ripening, residual level of αs-CN and β-CN was 12.02% and 80.96%, respectively. Three month-old cheese had improved indexes of lipid quality as well as improved reducing power and ability to scavenge free radicals. Ripening affected the content of Ca, P and Na whereas no significant changes of the other macro- and microelements of Kupres cheese were observed.Kupreški sir je tradicionalni bosanski punomasni tvrdi sir. U ovom istraživanju praćene su promjene profila proteina i masnih kiselina, udjela mineralnih tvari i antioksidacijskog potencijala tijekom tri mjeseca njegovog zrenja. Proteoliza je praćena elektroforezom ukupnih ekstrakata i frakcija topljivih u vodi u redukcijskim uvjetima, dok su profili masnih kiselina određivani plinskom kromatografijom. Udjel mineralnih tvari u zrelim sirevima određen je metodom induktivno spregnute plazme i optičke emisijske spektrometrije (ICP-OES) koja je korištena za makroelementie, kao i spektrometrijom masa uz induktivno spregnutu plazmu (ICP-MS) koja je korištena za mikroelemente. Zrenje kupreškog sira karakterizira relativno spora proteoliza tijekom prvog mjeseca, povećanje udjela poželjnih masnih kiselina i poboljšanje ostalih zdravstvenih indeksa masnih kiselina. Zrenje također poboljšava ukupni antioksidacijski kapacitet i reducirajuću sposobnost sira. Nakon 30 dana zrenja udjel VSN/TN i TCA/TN raste s 8,23 % i 2,25 % na 10,15 % i 3,59 %. Daljnje je zrenje uzrokovalo intenzivnije povećanje ovih parametara i intenzivniju degradaciju glavnih kazeina, posebno αs-CN. Nakon tri mjeseca zrenja rezidualni nivo αs-CN i β-CN iznosio je 12,02 %, odnosno 80,96 %. Sir koji je dozrijevao tri mjeseca imao je poboljšane indekse kvalitete lipida, kao i poboljšanu redukcijsku moći sposobnost uklanjanja slobodnih radikala. Zrenje je izazvalo značajne promjene udjela Ca, P i Na, ali nije utjecalo na udjele ostalih makro- i mikroelemenata kupreškog sira

Characterization of Proteins from Grain of Different Bread and Durum Wheat Genotypes

The classical Osborne wheat protein fractions (albumins, globulins, gliadins, and glutenins), as well as several proteins from each of the four subunits of gliadin using SDS-PAGE analyses, were determined in the grain of five bread (T. aestivum L.) and five durum wheat (T. durum Desf.) genotypes. In addition, content of tryptophan and wet gluten were analyzed. Gliadins and glutenins comprise from 58.17% to 65.27% and 56.25% to 64.48% of total proteins and as such account for both quantity and quality of the bread and durum wheat grain proteins, respectively. The ratio of gliadin/total glutenin varied from 0.49 to 1.01 and 0.57 to 1.06 among the bread and durum genotypes, respectively. According to SDS-PAGE analysis, bread wheat genotypes had a higher concentration of α + β + γ-subunits of gliadin (on average 61.54% of extractable proteins) than durum wheat (on average 55.32% of extractable proteins). However, low concentration of ω-subunit was found in both bread (0.50% to 2.53% of extractable proteins) and durum (3.65% to 6.99% of extractable proteins) wheat genotypes. On average, durum wheat contained significantly higher amounts of tryptophan and wet gluten (0.163% dry weight (d.w.) and 26.96% d.w., respectively) than bread wheat (0.147% d.w. and 24.18% d.w., respectively)

Labour market flexibility and security in the EU

The article deals with the profound changes (reducing various forms of security) that modern European labour markets are experiencing due to changes in dominant paradigms in the current period and to processes such as globalisation and flexibilisation. After analysing Eurostatʼs labour market and social security indicators, we could confirm that there are different flexibilisation \u27models\u27 in the EU since EU countries are using different forms of flexible employment as the primary source of flexibilisation. We also found that the \u27selection\u27 of a particular form of flexible employment is strongly correlated, among other factors, with the level of wealth accumulated in a particular society and that the different forms of flexible employment produce different levels of risk of poverty.Članek obravnava korenite spremembe (zmanjševanje različnih oblik varnosti), ki jih doživljajo moderni evropski trgi dela zaradi sprememb paradigem, ki prevladujejo v konkretnem času in procesov, kot sta globalizacija in fleksibilizacija. Z analizo kazalnikov Eurostata o trgu dela in socialni varnosti smo potrdili, da obstajajo različni \u27modeli\u27 fleksibilizacije v EU, ker države EU uporabljajo različne oblike fleksibilnega zaposlovanja, kot je primarni vir fleksibilizacije. Ugotovili smo tudi, da je \u27izbira\u27 posebne oblike fleksibilnega zaposlovanja močno povezana med drugim s stopnjo bogastva, akumuliranega v določeni družbi, in da različne oblike fleksibilnega zaposlovanja proizvajajo različne stopnje tveganja revščine

Some characteristics of European (flexible) labour markets

In this article, the author analyses the structure of the European labor market(s) and the correlation between the welfare state regimes and the types of labor markets in Europe. Using the data from the Labor Force Surveys and cluster analysis as a statistical tool, the author gets slightly different picture of European labor markets from those proposed by some other authors. The cluster analysis revealed 4 distinctive, regionally structured and coherent clusters (groups) of labor markets, which could be ranked from a more traditional, industrial type to the modern, flexible type of the labor market. Similar structure, with even greater regional coherence, is found regarding the characteristics of the labor market flexibility. It is argued that for such results cultural as well as economic factors, that are hidden behind the notion of welfare state regimes, are responsible