Optimization of Gluten-Free Bread Prepared from Rice Flour and Corn Starch

Zadatak ovog rada bio je ispitati utjecaj dodatka različitih omjera rižinog brašna i kukuruznog škroba, kao i različitih omjera hidrokoloida ksantan gume i psyllium praha, na kvalitetu kruha bez glutena te optimirati recepturu upotrebom metode odzivnih površina. Plan pokusa napravljen je prema potpunom faktorskom planu te su provedena probna pečenja uzoraka u kojima se udio rižinog brašna u smjesi s kukuruznim škrobom kretao od 50 do100 %, a udio psylliuma u smjesi sa ksantan gumom od 0 do 100 %. Nakon provedenih pečenja određena su kvalitativna svojstva kruha bez glutena: analiza teksturalnog profila, određivanje specifičnog volumena, instrumentalno određivanje boje u CIELab sustavu te senzorska ocjena uz upotrebu hedonističke skale u 9 stupnjeva. Rezultati istraživanja su pokazali da su se povećanjem udjela rižinog brašna smanjili čvrstoća i otpor žvakanju, a povećala se kohezivnost i koeficijent otpornosti kruha bez glutena. Dodatkom psyllium praha povećali su se čvrstoća, otpor žvakanju, elastičnost i kohezivnost, a boja kruha bila je značajno tamnija. Rižino brašno ipsyllium prah imali su pozitivan utjecaj na ukupnu senzorsku ocjenu. Izračunato je da optimalna receptura za proizvodnju kruha bez glutena sadrži 92,87 % rižinog brašna i 7,13 % kukuruznog škroba te 2,0 5% psyllium praha i 7,95 % ksantan gume.The objective of this study was to investigate the effect of adding different ratios of rice flour andcorn starch and different ratios of xanthan gum and psyllium husk powder on the quality of gluten-free breadand to optimize the formulation using response surface methodology. The experimental design followed thefull factorial plan, and baking trials were conducted in which the proportion of rice flour in the mixture withcornstarch ranged from 50 to 100% and the proportion of psyllium in the mixture with xanthan gum rangedfrom 0 to 100%. After baking, the qualitative characteristics of the gluten-free bread were determined: texturalprofile analysis, determination of the specific volume, instrumental color determination in the CIELab space,and sensory evaluation using a 9-point hedonic scale. The results of the study showed that increasing the rice flour content decreased the hardness and chewinessand the cohesiveness and resilience of the gluten-free bread. The addition of psyllium powder increasedhardness, chewiness, springiness and cohesiveness and resulted in darker breads. Rice flour and psylliumpowder had a positive effect on the overall sensory score. It was calculated that the optimal recipe for makinggluten-free bread contains 92.87% rice flour and 7.13% corn starch, as well as 2.05% psyllium powder and7.95% xanthan gum