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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Interakcija prehrambenih vlakana sa gradivnim materijama testa u postupku izrade pekarskih proizvoda snižene energije / ТHE INTERACTION OF DIETARY FIBRES WITH STRUCTURAL DOUGH COMPONENTS IN THE PROCESS OF MAKING DECREASE ENERGY BAKERY PRODUCTS

Filipović Jelena 30 October 2009 (has links)
<p>U radu je ispitana interakcija tri vrste komercijalnih prehrambenih vlakana (Fibrex, inulin HPX i inulin GR) sa strukturnim komponentama hlebnog testa. Na različitim pH vrednostima (pH 7, pH 5, pH 4 i pH 3) ispitane su fizikohemijske osobine vlakana, pri čemu Fibrex ima najveći kapacitet zadržavanja vode od 421% dok inulin GR najmanji od svega 4.2%. Na osnovu reolo&scaron;ke osobina testa sa vlaknima u količini od 5 i 10% dobijen je uvid u interakciju vlakana sa proteinskim kompleksom i klajsterisanim skrobom. Reolo&scaron;ke osobine hlebnog testa zavise od količine i vrste inkorporiranih vlakana&nbsp; dok pH vrednost vode za zames ima mali uticaj na ove pokazatelje. Dodatkom 5 i 10% fibrex-a i inulina HPX dobija se hleb dobrog kvaliteta, sa značajnim padom svarljivih ugljenih hidrata i promenjenog nutritivnog sastava koji ima osobine funkcionalne hrane pri čemu fibrex tamni boju a inulin HPX i GR vizuelno ne menja boju hleba u odnosu na hleb bez vlakana. Statistička obrada podataka je potvrdila pozitivan uticaj vlakana na testa u zamrznutom stanju. Koeficijenti diskriminacije pokazuju da je najveći uticaj vlakana na zavr&scaron;nu fermentaciju testa je posle 1 dana (199.006 i 5.739), a pozitivan uticaj vlakana na zapreminu hleba izražen je posle 30 dana (9.416) a na kvalitet sredine posle 60 dana (.841). Termodinamičkim merenjima kinetike zamrzavanja/odmrzavanja testa sa vlaknima utvrđeno je da inulina GR doprinosi skraćenju postupka &scaron;to potvrđuje koeficient determinacije R2 (0.966 i 0.981) dok testo sa fibrexom ima najmanji koeficijent determinacije R2 (0.939 i 0.951) &scaron;to pokazuje da ovo vlakno najlo&scaron;ije utiče na kinetiku zamrzavanja/odmrzavanja. Kinetika zamrzavanja/odmrzavanja može se definisati matematičkim modelom koja odgovara jednačini sa kvadratnim polinom , odnosno jednačini za nestacionarni temperaturni profil sa kvadratnim članom Y= b<sub>0</sub>+b<sub>1</sub><sup>*</sup>X +b<sub>2</sub><sup>*</sup>X<sup>2</sup>.</p> / <p>The interaction of three different commercial<br />fibers (Fibrex, inulin HPX and inulin GR) with<br />structural elements of bread dough was tested.<br />Physico/chemical fiber characteristics at<br />different pH values point that the greatest<br />water binding capacity (421%) is attributed to<br />fibrex, contrary to the value of 4,2%<br />experienced for inulin GR. Rheology of dough<br />containing 0 to 10% of either fiber type proved<br />the insight in the interaction between fibers<br />and proteins and also fibers and starch gels.<br />Dough rheology is influenced the most by fiber<br />characteristics and incorporated quantity,<br />contrary to pH value of water at mixing stage.<br />Statistical data interpretation proved the<br />positive contribution of fibers on dough at<br />freezing<br />Discrimination coefficients are confirming that,<br />on the whole, the greatest influence fibers have<br />on final proof after1 day of freezing (199.006<br />and 5.739) and their beneficial influence is<br />experienced after 30 and 60 days of freezing on<br />bread volume (9.416) and bread crumb quality<br />(0.841), respectively. Thermodynamic<br />measuring of freezing/thawing kinetics of<br />dough containing fibers point that inulin GR is<br />beneficial in shortening the procedure,<br />confirmed by values for determination<br />coefficient R&sup2; (0.966 and 0.981), contrary to the<br />contribution of Fibrex where the smallest<br />values for those coefficients were experienced,<br />R&sup2; (0.939 and 0.951 proving that fibrex is not<br />contributing to the freezing/thawing kinetics.<br />Freezing/thawing kinetics can be adequately<br />defined by the mathematical model of square<br />polynomial, i.e. equation for the non stationary<br />temperature profile with square Y= b<sub>0</sub>+b<sub>1</sub><sup>*</sup>X +b<sub>2</sub><sup>*</sup>X<sup>2</sup>.</p><p>Data presented in this thesis show that,<br />understanding interactions between fibers and<br />dough structure, by the addition of 5 or 10% of<br />either Fibrex or inulin HPX, high quality bread<br />attributed with a significant decrease of<br />digestible carbohydrates and modified nutritive<br />pattern accompanied with attributes of<br />functional food can be made, while Fibrex is<br />adversly contributing to crumb colour contrary<br />to inulin HPX and GR.</p>

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