Influence of trehalose addition on phenols, antioxidatnt activity, colour and texture of orange jellies during storage

U radu je istraživan utjecaj dodatka trehaloze na udio fenola, antioksidativnu aktivnost, boju i teksturu želea od naranče tijekom skladištenja od 135 dana. Vrijednosti istraživanih parametara ovisile su i o dodatku trehaloze (10%) i o pH vrijednosti uzoraka (3,5, 3,0 i 2,6). Udio fenola u svim uzorcima nakon pripreme povećava se sa snižavanjem pH vrijednosti tako da je najveći udio fenola bio u želeima pri pH 2,6 (1189,95 i 1128,84 mg/kg). Udio fenola u uzorku s dodatkom trehaloze pri pH 3,5 nakon pripreme (976,06 mg/kg) bio je veći nego u uzorku bez dodatka trehaloze (901,85 mg/kg), dok je u uzorcima s dodatkom trehaloze i pH 3,0 i 2,6 udio fenola bio manji u odnosu na želee bez dodatka trehaloze. Tijekom skladištenja došlo je do smanjenja udjela fenola u svim uzorcima. Uzorci s dodatkom trehaloze imali su veći udio fenola, osim u želeu s pH 3,5. Antioksidativna aktivnost svih uzoraka nakon pripreme bila je približno jednaka, bez obzira na dodatak trehaloze, pH i metodu određivanja. Od parametara teksture određeni su sila pucanja gela, lomljivost i adhezija. Smanjenjem pH vrijednosti sila pucanja se povećava, a lomljivost se smanjuje. Vrijednosti adhezije su bile znatno veće u uzorcima s pH 3,0 i 2,6.In this study influence of trehalose addition on phenol content, antioxidant activity, colour and texture of orange jellies during 135 days of storage. Investigated parameters depended on trehalose addition (10%) and sample pH value (3.5, 3.0 and 2.6). After preparation, phenol content in all samples increased with decrease of pH value, thus the highest phenol content was in samples with pH 2.6 (1189.95 and 1128.84 mg/kg). Phenol content in sample with trehalose addition with pH 3.5 (976.06 mg/kg) was higher than in sample without trehalose addition (901.85 mg/kg). Samples with trehalose addition with pH 3.0 and 2.6 had lower phenol content than samples without trehalose addition. During storage phenol content decreased. Samples with trehalose addition had higher phenol content, except in samples with pH 3.5. Antioxidant activity of all samples after preparation was similar regardless of trehalose addition, pH values and evaluation method. Rapture strength, brittleness and adhesiveness were determined as texture parameters. With decrease of pH value rupture strength increased while brittleness decreased. Adhesiveness was much higher in samples with pH 3.0 and 3.6