Protein profiles and total antioxidant capacity of water soluble and insoluble protein fractions of white cow cheese at different stage of ripening

This research is focused on proteolysis and total antioxidant capacity of proteins of white brined cheese prepared from overheated (90 degrees C, 10 minutes) cow milk. White brined cow cheese of overheated milk went through specific proteolytic changes during ripening that were result of high level of whey proteins incorporated into the gel matrix. Specificity was reflected through the relatively low level of soluble nitrogen fractions, the intensive and continual decrease of alpha(s)-caseins up to 15.42 % of initial content, slow degradation of beta-casein throughout the whole ripening period and high level of proteolytic products tightly bounded into gel matrix. Strong negative correlations (-0.97, -0.98 and -0.91; p lt 0.05) between ripening time and resudual alpha(s)-caseins, beta-casein and low molecular weight products were observed. Proteolysis also affected the total antioxidant capacity of both water soluble and water insoluble nitrogen fractions, but to different extents and with different trends. Total antioxidant capacity of water insoluble fraction increased slowly during the whole ripening period, wherease significant improvement of total antioxidant capacity of water soluble fraction started after 30 days of ripening. These findings could be useful for better understanding and control of the white brined cow cheese production

Uticaj genotipa sojinog zrna i HTC proizvodnog postupka na aktivnost tripsin inhibitora sojinog mleka

Kunitz inhibitor (KTI) and Bowman-Birk trypsin inhibitor (BBI) are inhibitors of digestive enzymes in raw soybeans. Due to their antinutritive properties in the active state, their inactivation by heat treatment is commonly used. Soymilk is a turbid and stable colloidal solution, obtained by thermal treatment of soybean. In this study soymilk was made on a pilot-plant scale from six soybean cultivars using hydrothermal cooking (HTC) as the production method. This procedure is significantly different from the traditional one. The aim of this investigation was to evaluate the impact of the HTC processing for soymilk production and different soybean genotypes on trypsin inhibitor content and activity. Obtained soymilk contained BBI in trace amounts, in the BBI-polymeric forms. The BBI monomeric forms were not detected. The soymilk of the investigated soybean genotypes had very similar KTI levels (2.34-2.99%). Results have suggested that the soybean genotype does not have substantial effects on the levels of KTI, as well as on the value of residual trypsin inhibitor activity (rTIA). The total content of TI and rTIA showed a strong dependence (r=0.91; p lt 0.05). HTC-soymilk rTIA was lt 20% (7.15-19.89%). These results have indicated that HTC processed soymilk is applicable for human consumption.U sirovoj soji Kunitz-ov (KTI) i Bowman-Birk-ov inhibitor tripsina (BBI) su inhibitori digestivnih enzima. Da bi se poboljšao nutritivni kvalitet hrane od soje, tripsin inhibitori (TI) se inaktiviraju uglavnom termickom obradom. Sojino mleko je mutni i koloidni rastvor, dobijen nakon termičkog tretmana sojinog zrna. U ovoj studiji sojino mleko je napravljeno od šest sorti soje u pilot postrojenju metodom koja uključuje hidrotermičko kuvanje (engl. hydrothermal cooking - HTC). Ovaj postupak se znatno razlikuje od tradicionalnog. Cilj ovog rada je bio da se proceni uticaj HTC postupka za proizvodnju sojinog mleka i različitih genotipova sojinog zrna na sadržaj i aktivnost tripsin inhibitora. Dobij eno sojino mleko je sadržalo BBI u tragovima, u formi BBI-polimera. BBI-monomerne forme nisu detektovane. Sojina mleka od ispitivanih genotipova soje imaju veoma slične sadržaj e KTI (2,34-2,99%). Rezultati su pokazali da genotip sojinog zrna nema značajne efekte na sadžaj KTI, kao i na vrednost rezidualne tripsin inhibitorske aktivnosti (rTIA). Ukupan sadržaj TI i vrednost rTIA je u snažnoj korelaciji (r= 0,91; p lt 0,05). HTC sojina mleka imala su vrednosti za rTIA lt 20% (7,15-19,89%). Ovi rezultati su pokazali da sojina mleka dobijena nakon HTC obrade mogu biti namenjena za ishranu ljudi

Characterization of sunflower seed and kernel proteins

Total sunflower proteins, storage proteins, and helianthinin (11S) and 2S albumin fractions and their respective subunits in seeds and kernels of three sunflower hybrids were analyzed. Protein contents were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and coupled with densitometry. The SDS-PAGE profiles of the seed and kernel proteins in the crude extracts for all genotypes showed a very similar number of protein bands (thirty two) in the electrophoretograms. Three polypeptide groups of helianthinin fraction were detected. Two of these were acidic (α, Mw = 36,800 - 42,900 Da and α', Mw = 31,000 - 35,300 Da), while one was basic (β, Mw=21,000 - 29,600 Da). The molecular weight of the 2S albumin proteins ranged from 11,500 to 20,100 Da. According to our results, there were significant differences among the seed and kernel protein contents. The 2S albumin content was significantly higher in kernels than in whole seeds of sunflower hybrids (P lt 0.05). By contrast, the 11S helianthinin content was significantly higher in seeds (where it ranged from 61.75 to 67.70% of totally extracted proteins) than in kernels (varied from 57.36 to 61.51% of totally extracted proteins) of sunflower hybrids (P lt 0.05)

Tehno-funkcionalne osobine izolata proteina graška

Due to high nutritive quality, good techno-functional properties and low cost, legume protein products are becoming the most appropriate alternative to protein products of animal origin. In food industries, these products are usually used as techno-functional additives which provide specific characteristics of final food products. Legume proteins are commonly used as flour, concentrates, and isolates. The greatest application on industrial scale has soy proteins, and to a lesser extent, in the past 20 years, pea protein isolates. The modest use of pea protein is partly a result of insufficient information relating to their techno-functional properties. This paper is an overview of techno-functional properties of pea proteins and their isolates. Also, the paper deals with the possible use of limited enzymatic hydrolysis as a method for the improvement of their techno-functional properties.Zahvaljujući visokoj nutritivnoj vrednosti, dobrim tehno-funkcionalnim karakteristikama i niskoj ceni, proteini leguminoza postaju najprihvatljivija alternativa za proteinske proizvode animalnog porekla. U industriji hrane ovi proizvodi najčešće se koriste kao tehno-funkcionalni aditivi kojima se obezbeđuje neka od karakteristika finalnog proizvoda. Proteini leguminoza najčešće se koriste kao proteinska brašna, koncentrati i izolati. U industrijskim razmerama najveću primenu imaju proteini soje i u znatno manjoj meri, u poslednjih 20 godina, proteinski izolati graška. Ređa upotreba proteina graška delom je posledica još uvek nedovoljno informacija o njihovim tehno-funkcionalnim karakteristikama. Ovaj rad predstavlja pregled tehno-funkcionalnih karakteristika proteina graška i njegovih izolata. Takođe, u ovom radu razmatra se i delimična proteoliza kao metod za poboljšanje tehno-funkcionalnih karakteristika proteina graška

Influence of different genotypes on trypsin inhibitor levels and activity in soybeans

This study describes the relationship between the two major trypsin inhibitors (TI) in soybean, i.e., the Kunitz (KTI) and Bowman-Birk (BBI) trypsin inhibitors, as well as between them and the corresponding trypsin inhibitor activity (TIA). Twelve investigated soybean genotypes showed significant differences in TI levels and TIA. A very strong positive correlation was found between the levels of KTI and total BBI (r = 0.94, P lt 0.05). No relationship was found between KTI, BBI or total TI and TIA. Based on this data, it appears that the levels of major TI in soybean are related. Understanding the relationship between trypsin inhibitors and their activities could be useful for further improvement of the health impacts of soy proteins

Proteinski sastav tofua korigovanog kvaliteta

Soybeans are an inexpensive, high-quality protein source. Soybeans have long been a staple of the human diet in Asia, especially as tofu, which is prepared from soymilk. In this study, tofu was made using a new production method which includes hydrothermal cooking (HTC) and rennin-pepsin coagulant. The effects of the addition of gallic acid to the slurry during tofu processing were studied. Tofu was made from two soybean genotypes: Lana and Balkan. The observed genotypes are characterized by relatively high content of total proteins in flour, from 45.88% to 48.83%. The prepared tofu samples are characterized by extremely high content of total proteins (52.17% - Lana tofu and 56.08% - Balkan tofu). The presence of gallic acid significantly affects the solubility of tofu protein. The applied modifications of traditional procedure of tofu production significantly improved sensory properties of soybean protein products.Tofu je želirani proteinski proizvod, koji se dobija koagulacijom zagrejanog sojinog mleka. Potrošačima naše populacije ne odgovara aroma 'zelenog zrna', takozvani 'leguminozni miris i ukus', koji se oseća u proizvodima soje pripremljenim na tradicionalni način. Sa namerom poboljšanja arome dobijenih sireva, pripremljen je tofu primenom hidrotermičkog tretmana i enzima za koagulaciju mleka (himozin-pepsin) uz dodatak galne kiselina, koja je jak antiseptik i antioksidant. Zahvaljujući visokom sadržaju ukupnih proteina sojinog semena (45,88-48,83% u obezmašćenom brašnu) i pripremljeni tofu se karakteriše visokim sadržajem ukupnih proteina (52,17% s.m.- Lana tofu i 65,08 % s.m. - Balkan tofu). Postupak dodatka galne kiseline menja sadržaj rastvorljivih proteina (27,48% - Lana tofu i 41,55% - Balkan tofu) koji se značajno razlikuje u odnosu na uzorke bez nje (14,20% - Lana tofu i 28,88% - Balkan tofu). Poliakrilamidnom-gel elektroforezom ekstrakta tofua pripremljenog uz dodatak galne kiseline razdvojen je veći broj komponenata, koje se ne uočavaju na elektroforegramima tofua nemodifikovanog kvaliteta. Gasnohromatografskom analizom isparljivih komponenata tofua registrovan je uglavnom acetaldehid, tako da je postignut cilj ublažavanja legulinoznog mirisa. Poboljšanje senzornih karakteristika potvrđuju i povoljne senzorne ocene koje su dobili uzorci pripremljeni sa galnom kiselinom (3,65 - Lana tofu i 3,87 - Balkan tofu)

Koliko smo upoznati sa osobinama i prisustvom mikotoksina u hrani?

The occurrence of mycotoxins in the food chain is an inevitable and serious problem that the world faces. Due to the very humid and warm climate, it can be expected that Serbia this and next year will be a very fertile ground for the development of toxigenic fungi. We need to be familiar with the properties of mycotoxins, the chemical structure and the basic mechanisms of the action of mycotoxins. So we can have the basics for developing protocols or methods for efficiently managing problems related to mycotoxins, as well as to understand their biological effects. The aim of the paper was to analyze how many students are familiar with the problem of mycotoxins in food. The research was carried out using anonymous questionnaire, which included questions about mycotoxins and mycotoxicosis. The surveyed students were selected randomly, and they had an equal chance of being selected for the sample. These were students of bachelor studies at the Institute of Food Technology and Biochemistry, Faculty of Agriculture, University of Belgrade. The survey was educational for interviewed students and they showed that they were in a very high percentage informed with basic characteristics of mycotoxins. As well as, they showed the best know aflatoxin characteristics. In addition, students showed relatively good knowledge of basic characteristics and other representatives of mycotoxins. The relatively good knowledge of the student's questionnaire about mycotoxin features can be a great basis for further work and improvement.Pojava mikotoksina u lancu ishrane je neizbežan i ozbiljan problem sa kojim se suočava svet. Zbog veoma vlažnih i toplih klimatskih uslova, može se očekivati da će Srbija ove i sledeće godine biti veoma pogodno tle za razvoj toksigenih gljiva. Moramo biti upoznati sa osobinama mikotoksina, hemijskom strukturom i osnovnim mehanizmima delovanja pojedinačnih mikotoksina, kako bismo imali osnove za razvoj protokola ili metoda za efi kasno upravljanje problemima vezanim za mikotoksine, kao i da bi se razumeli njihovi biološki efekti. Cilj rada je bio da se napravi analiza koliko su studenti upoznati sa problemom pojave mikotoksina u hrani. Istraživanje je sprovedeno pomoću anonimnog upitnika, koji je uključivao pitanja koja se tiču mikotoksina i mikotoksikoza. Anketirani studenti su odabrani nasumično, tj. studenti osnovnih studija na Institutu za prehrambenu tehnologiju i biohemiju, Poljoprivrednog fakulteta, Univerziteta u Beogradu imali su jednake šanse da budu izabrani za uzorak. Anketa je bila edukativna za anketirane studente i pokazala je da su u veoma visokom procentu upoznati sa osnovnim karakteristikama mikotoksina, kao i da od predstavnika pojedinih grupa mikotoksina, najbolje poznaju karakteristike afl atoksina. Pored toga, studenti su pokazali relativno dobro poznavanje osnovnih karakteristika i drugih predstavnika mikotoksina. Relativno dobro predznanje anketiranih studenta o osobinama mikotoksina, može biti odlična osnova za dalji rad i usavršavanje

Promene polipeptidne strukture sojinog proteinskog izolata pri termičkoj inaktivaciji antinutritivnih komponenti

The change of polypeptide composition of soybean isolates, prepared from samples treated by autoclaving in the aim of trypsin inhibitors inactivation (0.5 bar; 5,10 and 15 min.) was investigated. By densitometric analysis of SDS-PAGE-gels, the composition of soybean isolated protein was determined. According to our results, glycinin showed the highest content among proteins of soybean isolates. Depending on duration of soybeans heating, the percentage of glycinin in resulting isolate was 47.14-53.08%. High content of acidic (30.02-30.98%) and basic (15.12-18.24%) polypeptides of glycinin was registered. High content of a-subunit of P-conlycinin was determined (11.49-8.99%). The presence of Bowman-Birk TI as well as lypoxigenase, was not registered in any of protein isolates.Cilj ovog rada bio je da se ispita uticaj nadpritiska 0,5 bara, radne temperature 96°C u trajanju od 5,10 i 15 minuta u autoklavu na promene polipeptidne strukture dobijenih proteinskih Izolata iz lomljenog sojinog zrna. Potvrđena je termostabilnost molekulaglicinina (47,14-53,08%), i manja stabilnost B-konglicinina (15,31-25,45%). Denzitomelrijska analiza SDS-elektroforegrama ukazuje na izraženu termostabilnost kiselih A1,2,4(27,50-26,31%) i baznih B1,2,3,4(18,24-15,12%) polipeptlda glicinina. Sadržaj a-polipeptida fikonglicinina pokazuje linearnu zavisnost od trajanja primenjenih tretmana (10,92-8,99%). Nakon ovih tretmana zapažena je smanjena tripsininhibitorska aktivnost (TIA), pri čemu je nosilac TIA Kunitz-ov TI (5,00-8,80%), dok je Bowman-Birk-ov inhibitor registrovan samo kod izolata iz netretiranog lomljenog sojinog zrna (3,92%)

Biološki aktivni faktori sojinog proteinskog izolata dobijenog iz hidrotermički tretiranog lomljenog zrna

The influence of the treatment duration and steam pressure on inactivation of biologically active components is presented in this paper. Steaming of cracked soya bean grains used for the protein isolate preparation of efficiently inactivated trypsin inhibitors (TI). Residual activity of Kunitz inhibitor was only detected (2.59-1.70%). The most suitable properties for utilisation in food technology were found for soya bean protein isolate (SPI) prepared from cracked soya bean grains hydrothermally treated for 10 minutes, using steam pressure of 1.5 bar. Such SPI contained 12.34% of residual TI activity, and compared to the untreated sample it contained similar levels of lectin (0.29%) and phytic acid (1.88%).Primena soje i proizvoda na bazi proteina soje ograničena je prisustvom komponenti sa antinutritivnim dejstvom, poput inhibitora proteinaza fitinske kiseline, lektina. Prisustvo ovih komponenti prouzrokovalo je potrebu za iznalaženjem optimalnih rešenja za poboljšanje kvaliteta proizvoda od proteina soje. Cilj ovog rada bio je da se ispita uticaj na promenu aktivnosti biološki aktivnih komponenti proteinskog izolata lomljenog sojinog zrna nakon produvavanja vodenom parom (pri nadpritisku 0,5 bar) u kraćim vremenskim intervalima (5, 10 i 15 minuta). Nakon primenjenog hidrotermičkog tretmana zapaženo je znatno smanjenje tripsin inhibitorske aktivnosti (TIA) sa 72,34% za netretirani proteinski izolat na 6,55% za izolat nakon 15-ominutnog tretmana, pri čemu je nosilac TIA Kunitz-ov tripsin inhibitor (TI) (2,59-1,70%), dok je Bowman-Birk-ov inhibitor registrovan samo kod izolata od netretiranog lomljenjog sojinog zrna (3,92%). SDS elektroforezom je ustanovljena promena u prisustvu lektina kod izolata dobijenih od tretiranih uzoraka (0,77-0,21%) u poređenju sa izolatom dobijenog od netretiranog zrna (1,96%). Rezultati ukazuju da sadržaji ukupnog rastvorljivog fosfora (11,35-5,96 mg P/g), fitinskog fosfora (1,09-0,53%) i fitinske kiseline (1,88-3,87%) pri ovako kratkotrajnim tretmanima (5, 10 i 15 min) nisu u direktnoj zavisnosti od dužine tretmana

Prinos i kvalitet sojinog mleka i tofua zavisno od načina proizvodnje

Soymilk and tofu are traditional and important source of protein in Asian diets. Soymilk is a watery extract of full-fat soybean. Tofu is a nutritional, protein gel, a kind of soybean product. Yield and quality are affected by several factors, such as variety or cultivar, soybean growth environment and processing methods. Processing factors, which affect the quality of soymilk and tofu, include soaking time and temperature, grinding temperature, soy milk heating rate, stirring speed, type and concentration of coagulant, method of adding coagulant to soy milk, and the weight and time of press. Traditionally prepared soymilk has bean-like flavour owing to lipid oxidation catalyzed by lipoxygenase during soaking and grinding. This flavor is unacceptable to most consumers and is the major obstacle to widespread acceptance of almost all soy food products, especially soymilk and tofu. A steam-infusion cooking process, known as hydrothermal cooking (HTC), was developed to produce soymilk continuously from ground full-fat soy flour. HTC-processed soymilk had less bean-like flavour because of the much shorter time for lipoxygenase to be active and because of the steam flashing stripped volatiles. Coagulation properties of soymilk are critical to achieving high yields and desired texture of tofu. Magnesium or calcium chloride was the most commonly used coagulating agent. The objectives of the present study were to research the effects of HTC processing conditions (at 0.8 bar above the atmospheric pressure; at temperature 110°C; during 8 minutes) and coagulation of soymilk protein with proteinases - himosin and pepsin on yield and quality of soymilk and tofu. Tofu prepared from Lana cultivar expresed the most acceptable sensory characteristics, while the chemical properties were registered for tofu prepared from ZPS-015.Sojino mleko je vodeni ekstrakt celog semena soje, a tofu je želirani proteinski proizvod koji se dobija koagulacijom zagrejanog sojinog mleka. Tradicionalnim načinom proizvodnje dobija se sojino mleko i tofu karakterističnog - leguminoznog mirisa i ukusa. Naša istraživanja imaju za cilj pripremu sojinog mleka i tofua od domaćih sorti soje (tri različita kultivara: Nena, ZPS-015 i Lana) modifikovanim načinom pripreme. Drobljenje i kuvanje namočene soje vršeno je pod nadpritiskom (0,8 bar), visokom temperaturom (110°C) i kratko vreme (8 min; hidrotermičko kuvanje - HTC). Nije korišćena tradicionalna metoda koagulacije sojinog mleka (dodatak CuSo4 ili MgCl2), već proteolitički enzimi - himozin i pepsin. Uočava se veliki stepen iskorišćenosti i izuzetna ekonomičnost sorte soje ZPS-015, gde je prinos tofua skoro 100%. Naime, od 1kg sojinog zrna dobija se 1,93 kg tofua dok je prinos sojinog mleka izjednačen kod sve tri sorte (6,63-6,71L mleka/kg sojinog zrna). Tofu pripremljen od soje sorte Lana može se okarakterisati kao izuzetno hranljiva i kvalitetna namirnica u svakodnevnoj i dijetetskoj ishrani obzirom na bogat sadržaj proteina (13,08%), visokih ocena senzornih karakteristika (srednja ponderisana ocena 4,63; srednja ocena za miris i ukus 4,7) i na to da je ovo varijetet selekcionisan bez Kunicovog tripsin inhibitora koji, ukoliko nije izbalansiran, može imati nepoželjnu antinutritivnu aktivnost. Proteinski proizvodi pripremani ovim načinom proizvodnje (sojino mleko - 15,72-16,61% i tofu - 13,08-15,59) sadrže znatno više ukupnih proteina nego komercijalni (mleko - 4,40%; tofu - 8,10-8,86%)