Different researches on optimizing the shelf life of pastries (gingerbread, sponge cakes) that are produced by adding sea buckthorn flour (2 - 4% by weight of the flour used) are presented in this study. This study shows the impact of biologically active substances on structural and mechanical, physicochemical, microbiological properties as well as the antioxidant activity of products under the conditions of in vitro gastric digestion. It has been demonstrated that the sea buckthorn flour increases the porosity of pastries, reduces the wet gluten amount and this contributes to moisture loss. The organoleptic assessment indicates that the addition of 2% sea buckthorn flour improves the appearance, the color and the consistency of pastries. Microbiological analysis showed that samples with added sea buckthorn flour exhibit microbiological stability due to the sea buckthorn chemical composition. The antiradical activity DPPH^• in conditions of in vitro gastric digestion of the samples with added sea buckthorn flour increases in a positive way, indicating a clearly positive effect on health.