| Sažetak | Cilj diplomskog rada bio je modeliranje promjene boje čajnog peciva tijekom 10 minuta pečenja na 205 °C. Uzorci su proizvedeni u laboratorijskim uvjetima od različitih tipova pšeničnog brašna. Od svakog tipa brašna napravljene su tri vrste zamjesa (standardni, suhi i vlažni) koji se razlikuju po udjelu vode. Svaki uzorak je skeniran, slike obrađene računalnom analizom slike pomoću programa ImageJ. Dobiveni rezultati ukupne promjene boje čajnog peciva prikazani su grafički, rezultati svjetline tablično te su korišteni za određivanje kinetičkih parametara kod modela reakcija nultog, prvog i drugog reda.
Iz rezultata je vidljivo da tijekom pečenja dolazi do tamnjenja čajnog peciva (uslijed Maillardovih reakcija i karamelizacije), što vrijedi za sve tri vrste zamjesa (vrijednosti ukupne promjene boje u 10. minuti pečenja iznosile su: referentno brašno: 23,56; cjelovito: 6,99; T-400: 23,29; T-550: 17,49; T-850: 12,34; T-1100: 12,97). Iznimka je čajno pecivo od cjelovitog brašna kod kojeg je očitano smanjenje ukupne promjene boje pri kraju procesa pečenja (vrijednost ukupne promjene boje u 0. minuti bila je 3,05, u 5. minuti 7,54, a u 10. minuti 6,99). Uspoređujući sve rezultate ukupne promjene boje, uzorci s manjim udjelom vode (suhi zamjes) imali su najmanju ukupnu promjenu boje. Nakon provedenog modeliranja, promjena boje čajnog peciva od cjelovitog brašna, te brašna tipa T-1100 i T-850 najbolje je opisana matematičkim modelom drugog reda linearnog oblika, a od brašna tipa T-400 i referentnog brašna matematičkim modelom nultog reda. Kod uzoraka čajnog peciva od brašna tipa T-550 promjenu boje najbolje opisuje model dugog reda linearnog oblika, odnosno, nultog reda. |
| Sažetak (engleski) | The aim of this thesis was modeling the change of color of tea cookies during 10 minutes of baking at 205 °C. Samples were made in laboratory conditions, from different types of wheat flour. Each type of flour was used to make three types of mixing (standard, dry and wet) that differ in amount of water. Each sample was scaned, the images were analysed with digital image analysis using program called ImageJ. Obtained results of total color change were displayed graphically, results of lightness in a table and they were used to determine kinetics parameters for models of reactions of zero, first and second order. According to the results, the cookies were started to darken during baking (due to Maillard’s reactions and caramelization) and it could be applied for all types of mixing (the value of total color change at the 10. minute of baking were: standard flour: 23.56; integral: 6.99; T-400: 23.29; T-550: 17.49; T-850: 12.34; T-1100: 12.97). The cookies from integral flour were an exception, where the total color change was decreasing at the end of baking process (value of total color change at zero minute was 3.05, at 5. minute 7.54, and at 10. minute 6.99). Comparing all the results of total color change, the samples with the lowest amount of water (the dry mixing) had the lowest value of total color change. After performed modelling, the change of color of cookies made from integral flour and flour T-1100 and T-850 were best described with mathematical models of second order linear form, and cookies from flour T-400 and standard with mathematical models of zero order. The color change of samples of cookies made from flour T-550 was best described with the model of second order linear form or with model of zero order. |
