Utjecaj različitih šećera na temperaturu staklastog prijelaza osmotski dehidratirane kore naranče

Osmotska dehidratacija, osobito uz prethodnu obradu ultrazvukom značajno utječe na termofizička svojstva, fazne prijelaze i stanje vode u hrani. Pomoću diferencijalne motridbene kalorimetrije (DSC) mogu se dobiti osnovne informacije o faznim prijelazima kao što je staklasti prijelaz, koji pojašnjava pojam stabilnosti hrane tijekom procesiranja i skladištenja. Cilj rada bio je istražiti utjecaj različitih šećera (fruktoze, saharoze) i njihovih kombinacija s trehalozom (45% F + 10% T i 45% F + 20% T; 45% S + 10% T i 45% S + 20% T) te narančinog sirupa (65% NS) na temperaturu staklastog prijelaza osmotski dehidratirane i liofilizirane kore naranče. Također je praćen njihov utjecaj na boju (albeda i flaveda) i teksturu kore naranče. Obrada je provedena u uvjetima atmosferskog tlaka uz miješanje (OD), vakuuma (PVOD) i vakuuma s primjenom ultrazvuka (UZPVOD). Utjecaj trehaloze na porast Tg bio je najveći (oko 15 °C) na primjeru obrada sa kombinacijama saharoze i trehaloze. Povećanje koncentracija šećera imalo je značajan utjecaj na indeks učinkovitosti procesa osmotske dehidratacije (DEI). Pad L* vrijednosti kod svih obrada bio je veći u više poroznom albedu. Ultrazvučna pulsirajuća vakuum obrada (UZPVOD) je značajnije utjecala na omekšavanje teksture od osmotske dehidratacije pri atmosferskom tlaku (OD) i pulsirajuće vakuum obrade (PVOD). Osmotic dehydration, especially with pre-treatment ultrasound significantly affects the thermo-physical properties, phase transitions and the state of water in foods. Using differential scanning calorimetry (DSC) can be obtained by the basic information of phase transitions such as the glass transition, which illustrates the concept of the stability of the food during processing and storage. The aim of this study was to investigate the effect of different sugars (fructose, sucrose) and their combination with trehalose (45% F + T 10% and 45% F + 20% T, 45% S + 10% T and 45% S + 20% T) and orange syrup (65% DC) on the glass transition temperature osmotically dehydrated and freeze-dried orange peel. It is also accompanied by their effect on the color (albedo and flavedo) and texture of orange peel. Treatment is carried out under atmospheric pressure with stirring (AT), a vacuum (PVOD) and with vacuum application of ultrasound (UZPVOD). Effect of trehalose on the increase was highest Tg (about 15 ° C) for example by treatment with a combination of sucrose and trehalose. Increasing the concentration of sugar had a significant impact on the index of efficiency of the process of osmotic dehydration (DEI). Decline of L * values in all treatment was higher in the more porous albedo. Ultrasound pulsed vacuum processing (UZPVOD) has materially affected on the softening texture of osmotic dehydration at atmospheric pressure (OD) and pulsed vacuum processing (PVOD).