Osmotic Dehydration of Apples in a Saccharose Solution Containing Fragrant Agrimony or Rosehip Extract

In the present study, extracts from the fragrant agrimony (Agrimonia procera Wallr.) herb and the pseudo-fruits of rose (Rosa rugosa) were incorporated into a 50% sucrose solution used for the osmotic dehydration of Champion apples (Malus domestica Borkh.). This approach enabled the investigation of the migration of fragrant agrimony and rose polyphenols-both total polyphenols and their main representatives-during the dehydration process of apples, which are among the most popular fruits due to their health-promoting and nutritional properties. The total polyphenol content was determined using spectrophotometric methods, while the major individual compounds were quantified by UHPLC-DAD-MS. At a polyphenol content of 4 g/L in the solution, a more intensive water migration (water loss of about 3 g/g DM) from the fruit tissue was achieved for both extracts compared to the pure sucrose solution. However, no relationship between the polyphenol level in the hypertonic solution and the migration of sucrose into the apple tissue was observed. With regard to polyphenolic compounds, the level of polyphenols in apples dehydrated in the presence of extracts, compared to those dehydrated in pure sucrose solution, increased with the extract dose. The maximum value-approximately 825 mg/100 g DM of total polyphenols-was obtained at an extract concentration of 6 g/L, derived from both fragrant agrimony herb and rose pseudo-fruit. In the apples dehydrated using the extracts, the presence of phenolic compounds not found in fresh apples, characteristic of the applied extracts, such as ellagitannins, ellagic acid, flavonols including quercetin and kaempferol glycosides, as well as flavones, including derivatives of apigenin and luteolin, was observed. These findings indicate that the use of fragrant agrimony and rose extracts in osmotic dehydration may serve as an effective strategy for enhancing the polyphenolic profile and functional value of dehydrated apple products.