Izboljšanje prehranske vrednosti in trajnosti kruha z dodatkom grozdnih tropin in oljčne pogače

Šporin, Monika (author), Smole Možina, Sonja (mentor)

Namen raziskave je bil preučiti vpliv dodatka mletih grozdnih tropin (MGT) in oljčne pogače (OP) na senzorične lastnosti kruha, vsebnost fenolnih spojin in prehranske vlaknine, antioksidativno aktivnost in protimikrobno delovanje. S farinografsko analizo smo analizirali reološke lastnosti testa. Kruhu smo izmerili volumen, trdoto in barvo ter opravili senzorično analizo kruha. Z metodo Folin-Ciocalteu smo določili vsebnost skupnih fenolnih spojin v MGT in OP, testu ter kruhu, z metodama DPPH• in FRAP pa antioksidativno aktivnost. Vsebnost posameznih fenolnih spojin smo določili z metodo LC-MS. Z encimsko-gravimetrično metodo smo določili vsebnost topne, netopne in skupne prehranske vlaknine. Analizirali smo protimikrobno aktivnost brez in z inokulacijo kontrolnih sevov plesni. Dodatek MGT je vplival na reološke lastnosti testa. Dodatek sorte 'Merlot' je podaljšal čas razvoja in stabilnost testa ter zmanjšal omehčanje, medtem ko je sorta 'Zelen' na testirane parametre izkazovala nasproten učinek. Volumen je bil pri vseh kruhih manjši v primerjavi s kontrolnim, trdota večja, barva kruha pa značilno spremenjena. Površina kruha in poroznost sredice sta postali bolj nehomogeni in pore v sredici večje. Prožnost sredice in elastičnost skorje sta se zmanjšali, drobljivost, lepljivost sredice in občutek peskavosti med žvečenjem pa povečali, prav tako vonj po kislem in sladkem. Na kisel okus, pookus in tujo aromo je vplival dodatek MGT, OP pa na grenak okus. Vsebnost skupnih fenolnih spojin se je z dodatki povečala, ravno tako antioksidativna aktivnost. Analiza LC-MS je pokazala nestabilnost določenih fenolnih spojin, kljub prisotnosti v dodatkih jih v kruhu ni bilo več zaznati. Vsebnost skupne prehranske vlaknine se je povečala ob dodatku MGT obeh sort, OP nanjo ni imela vpliva. Analiza protimikrobnega delovanja brez inokulacije je pokazala inhibitorno delovanje MGT obeh sort, rast plesni na kruhu z OP pa je bila intenzivnejša kot pri kontrolnem kruhu. Analiza z inokulacijo posameznih sevov plesni ni pokazala inhibitornega delovanja.

• Language: Slovenian
• Keywords: kruh, grozdne tropine, oljčna pogača, reološke lastnosti testa, senzorične lastnosti, fenolne spojine, antioksidativna aktivnost, prehranska vlaknina, protimikrobno delovanje
• Work type: Doctoral dissertation
• Typology: 2.08 - Doctoral Dissertation
• Organization: BF - Biotechnical Faculty
• Publisher: [M. Šporin]
• Year: 2019
• PID: 20.500.12556/RUL-108354
• UDC: 664.64.016:641.1:543.2/.9:579.67
• COBISS.SI-ID: 5079928
• Publication date in RUL: 29.06.2019

Secondary language

• Language: English
• Title: Improving the nutritional value and a shelf life of bread with the addition of grape pomace and olive cake

Abstract

The aim of the present study was to compare the effects of ground grape pomace (GGP) and olive cake (OC) addition on the sensory properties, content of phenolic compounds and dietary fiber, antioxidant and antimicrobial activity of wheat bread. Dough rheological characteristics were analyzed with farinograph analysis. Bread volume, firmness and color were measured, a sensory analysis of bread was made. The content of total phenolic compounds in GGP and OC, dough and bread were determined with the Folin–Ciocalteu method. Antioxidant activity were determined with the DPPH• and FRAP methods and content of individual phenolic compounds with the LC-MS method. The enzymatic-gravimetric method was used to determine the content of soluble, insoluble and total dietary fibers. Antimicrobial activity was analyzed with and without the inoculation of chosen mold strains. The addition of GGP affected the rheological characteristics of dough; the addition of variety 'Merlot' has extended the dough development time and stability, as well as reduced the degree of softening. The variety 'Zelen' had a reverse effect. The volume was lower in all breads with GGP and OC addition in comparison to the control bread, the firmness was greater and the bread color was changed. The crust surface and crumb pores were inhomogeneous and the pores were bigger. The springiness and toughness of the crust was lower, crumbliness, adhesivity and the sand feeling during chewing were increased, as well as the sour and sweet odour. The addition of GGP caused the sour taste, aftertaste and off-flavor, while the addition of OC enhanced the bitter taste. The content of the total phenolic compounds was getting higher with the addition of GGP and OC, so did the antioxidant activity. The LC-MS analysis has shown the instability of some phenolic compounds, despite the presence in GGP and OC, these were not present in the bread. The content of total dietary fiber got higher with the GGP addition of both varieties, while OC had no impact on it. The analysis of antimicrobial activity without inoculation has shown inhibitory activity of GGP of both varieties. The mold growth was more intense on the bread with OC as on the control bread. The analysis with inoculation of individual mold strains has shown no inhibitory activity.

• Keywords: bread, grape pomace, olive cake, rheological properties of the dough, sensory properties, phenolic compounds, antioxidant activity, dietary fiber, antimicrobial activity