The Optimization of Gluten-Free Bread Production from a Mixture of Rice Flour and Quercus rotundifolia Oak Acorn Flour

Abstract

Zadatak ovog diplomskog rada bio je ispitati utjecaj različitih omjera rižinog brašna i brašna žira hrasta Quercus rotundifolia (100:0, 50:50, 0:100), kao i utjecaja dodatka različitih količina vode (90, 100 i 110 %) pri zamjesu tijesta na kvalitetu kruha bez glutena. Izvršena su eksperimentalna pečenja i analiza kvalitativnih karakteristika kruha. Mjeren je specifični volumen i omjer visine i širine kruha, analiziran je teksturalni profil te je određena boja prema CIELab sustavu. Također, provedena je senzorska ocjena proizvedenih uzoraka kruha. Rezultati su pokazali da se povećanjem udjela brašna žira smanjuju specifični volumen i kohezivnost kruha, dok se čvrstoća povećava. Veće količine brašna žira u recepturi zahtijevale su i veću količinu dodane vode u zamjes. Također, brašno žira je značajno utjecala na tamnjenje kore i sredine kruha. Unatoč promjenama u teksturi i volumenu kruh s brašnom žira nije imao značajno lošije senzorske ocjene od kruha bez glutena s rižinim brašnom. Na temelju dobivenih rezultata može se zaključiti da se brašno žira hrasta Quercus rotundifolia može uspješno koristiti u visokim udjelima za proizvodnju kruha bez glutena, ali su potrebna daljnja istraživanja za optimizaciju recepture i procesa.The objective of this thesis was to examine the impact of different ratios of rice flour and acorn flour from Quercus rotundifolia (100:0, 50:50, 0:100), as well as the effect of adding varying amounts of water (90, 100, and 110%) during dough mixing on the quality of gluten-free bread. Test baking and analysis of the qualitative characteristics of the bread were conducted. Specific volume and height-to-width ratio of the bread were measured, the textural profile was analyzed, and color was determined according to the CIELab system. Additionally, a sensory evaluation of the produced bread samples was carried out. The results showed that increasing the proportion of acorn flour reduced the specific volume and cohesiveness of the bread, while the firmness increased. Larger amounts of acorn flour in the recipe required a greater amount of added water in the dough. Acorn flour also significantly affected the darkening of the crust and crumb of the bread. Despite changes in texture and volume, bread with acorn flour did not receive significantly lower sensory scores compared to gluten-free bread with rice flour. Based on the obtained results, it can be concluded that acorn flour from Quercus rotundifolia can be successfully used in high proportions for the production of gluten-free bread, but further research is needed to optimize the recipe and process