engleski

Thermophysical properties of sour cherry fillings

The fruit fillings designed for bakery products are expected to be stable not only at high temperatures, but also under different storage conditions, such as freezing. The aim of this study was to investigate the influence of sugars (trehalose and sucrose) and hydrocolloids (guar gum and xanthan) on thermophysical properties of sour cherry fillings. Sour cherry fillings were prepared by mixing juice with 0.6% of hydrocolloids and 50% of sugars. The thermal analysis of the sour cherry fillings was performed using a differential scanning calorimeter. Samples were analysed by two different methods, depending on the starting temperature of measurement (25 °C or - 60 °C). The parameters of the crystallisation (Tco-onset, Tcp-peak, Tce-endset and enthalpy of crystallisation-ΔHc), glass transition (onset and midpoint temperatures - Tg’o and Tg’m and change of specific heat capacity-Δcp) and melting (Tmo- onset, Tmp-peak, Tme-endset and enthalpy of melting-ΔHm) were monitored. As expected, sour cherry juice had the highest melting temperatures (Tmo, Tmp, Tme ranged from - 5 to 5.7 °C), the highest values of enthalpies (ΔHm ranged from 180.9 to 193.4 J/g ; ΔHc about 180 J/g) and the highest crystallisation temperatures (Tco, Tcp, Tce ranged from - 10 to - 15 °C) in comparison to fillings. The sour cherry fillings with guar addition had lower values of all measured thermophysical parameters in comparison with xanthan preparations. Sugar type had also impact on the evaluated properties. The sucrose-based fillings showed lower Tg’ values compared to the trehalose systems, which emphasizes the importance of trehalose addition in increasing the stability of the system, particularly in glass transition temperature range.

sour cherry fillings ; sugars ; hydrocolloids ; thermophysical properties

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