There are several thousand different cultivars of apple trees but only a limited number are cultivated on an industrial scale. Old cultivars can be useful, for example, in the processing industry due to their different composition. In many cases, they have higher organic acid content. The content of mineral components, colour, and polyphenols in the fruit of 7 old apple tree cultivars, growing in the Wolinski National Park, was studied. The changes that occurred in the fruit after freeze-drying were also evaluated. The trees from which the fruit was picked for analysis, despite the lack of chemical protection, were fruiting and the apples had only a few symptoms of damage caused by pests or diseases. The fruit was characterised by a high soluble solids content (14.4-16.4%), in which sugars and especially fructose dominated. The number of organic acids varied greatly and ranged from 0.27 (Oberlander Himbeerapfel) g to 1.07 g/100 g (Winter Goldparmane). The content of polyphenols in fresh apples ranged from 186 mg (Horneburger Pfannkuchenapfel) to 354 mg/100 g (Winter Goldparmane) and increased after freeze-drying from 666 mg (Weisser Winterkalvill) to 1486 mg/100 g (Winter Goldparmane). The dominant group of polyphenolic compounds was phenolic acid. The freeze-drying process caused unfavourable changes in the colour of the pulp. The fruits of Oberlander Himbeerapfel cultivar were most susceptible to these changes. However, the least darkened fruit of Horneburger Pfannkuchenapfel.

The study of alternative food sources or ingredients that can partially replace or enrich today’s food is a perspective direction. The possibility of using horse chestnut (Aesculus hippocastanum) and chestnut (Castanea sativa) fruits in the baking industry as an admixture to wheat flour has been determined. The addition of flours from these fruits at a level of 10% increases the number of minerals in the flour mixture and also enriches the mixture in saponins, coumarins, and tannins. However, it is necessary to remove excess saponins from horse chestnut. The amylograph has shown that flour from horse chestnut fruit has optimal parameters for baking mixed bread. Farinograph tests showed that a 10% addition of ground horse chestnut to wheat flour had the best baking properties. Mixtures with 10 and 15% chestnut addition showed the best baking characteristic.