Impact of different drying methods on the physicochemical and bioactive properties of quince fruit

Impact of different drying methods on the physicochemical and bioactive properties of quince fruit (Cydonia oblonga Mill.).

Quince (Cydonia oblonga Mill.), due to its valuable bioactive properties and high health potential, is becoming increasingly popular in preventing many diseases caused by free radicals. Due to the high hardness of the pulp and its bitter and astringent taste, quinces are rarely consumed as fresh fruits; they are much more commonly found in the form of various processed products or as dried additives, for example, for tea. Thermal processing (including drying) affects not only the content of bioactive compounds but also the antioxidant activity and organoleptic characteristics. Therefore, in this study, the physicochemical properties of quinces (including dry matter content, soluble solids content (°Brix), water activity (aw), pH, total acidity, and color changes (in the Lab* space)) were examined, both fresh and dried by various methods, i.e., lyophilization and convection at temperatures of 50°C and 70°C.

Considering the excellent taste and bioactive properties of common quince, introducing it into the daily diet, whether in traditional forms (dried fruits, fruit preserves) or as dietary supplements, can be an important element in preventing many lifestyle-related diseases.

Quince:

Quince (Cydonia oblonga Mill.) is one of the oldest fruit species in the world. It originates from Southeast Asia but is found on many continents, including Europe, especially in Southern Europe. Quince (Cydonia oblonga Mill.) belongs to the class of dicotyledons, in the rose family. It received its generic name from the Romans, who, upon discovering the tree in the Cretan city of Kydonia, named it malum cydonium, meaning apple from Kydonia. In Polish climatic conditions, quince reaches an average height of 3 m. In Polish conditions, the fruits ripen relatively late, typically in late September or even at the end of October.

Selected research methods:

Dry Matter Content

• The dry matter content in quince samples was determined by the gravimetric method, following the AOAC method (2000). Vessels were weighed and cooled, then 5.0 g (with an accuracy of 0.0001 g) of samples were weighed on an analytical balance (AS 220/X, Radwag, Radom, Poland). The samples were dried in a laboratory dryer (SUP 200 W, Wamed, Warsaw, Poland) for 72 hours at 105 °C. The dry matter content was calculated based on weight differences, and the result was expressed as a percentage (%).

Water Activity (aw)

• Water activity (aw) was measured using a portable water activity meter with temperature stabilization, the AquaLab water activity meter (Decagon Devices, Inc., Pullman, WA, USA).

pH

• pH measurement in the tested samples was conducted using the potentiometric method, using a laboratory pH probe (Elmetron CP-511, Elmetron G.P., Zabrze, Poland), at room temperature (20 °C).