Medlar Jam Production (Mespilus germanica) with the Use of Sous Vide Method

Abstract

The aim of this study was to evaluate the influence of sous vide technology on the chemical properties of fruit jams produced with medlar fruit (Mespilus germanica L.). The fruit jams were produced using sous vide technology at different temperatures: 60 °C, 70 °C, and 80 °C. The fruit jams were also produced at 100 °C using the traditional cooking method. Experimentally produced samples were evaluated by the following methods: total polyphenols content, ferric reducing antioxidant power assay (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and organic acid determination. Among sous vide-processed samples, the samples with the highest (p < 0.05) antioxidant activity were processed at 80 °C, containing pectin; the results were the following: phenols content 0.56 ± 0.01 mg gallic acid/kg; FRAP antioxidant activity 0.32 ± 0.01 µmol Trolox/g; DPPH antioxidant activity 21.39 ± 0.33%. The obtained results showed that fruit jam production with the use of sous vide technology can affect antioxidant capacity of this food commodity. The research also provided important information about non-traditional fruit, such as medlar fruit (Mespilus germanica L.), and its processing by sous vide technology. Certainly, more analyses are necessary to give a clearer picture of the changes in medlar fruit during processing at different temperatures, and processing technologies, especially because there are presently no publications about the use of medlar fruit as a raw material in fruit jam preparation.