This article presents the results of a study on a red rice-based beverage containing plant extracts, fermented with Lactobacillus delbrueckii subsp. bulgaricus. The aim of the work was to evaluate the effect of extracts of rhodiola, eleutherococcus, licorice, rosemary, and basil on the polyphenol content, antioxidant activity, microbiological parameters, and pH during the fermentation of the rice base. It was found that the highest polyphenol content was observed in the samples with rhodiola (0.153 mg GAE/mL) and eleutherococcus (0.138 mg GAE/mL), compared to the control value of 0.057 mg GAE/mL. Antioxidant activity was also maximal when using rhodiola (87.93%) and eleutherococcus (81.90%), whereas the control sample without extracts showed a value of 14.66%. In all variants with plant additives, an increase in L. bulgaricus biomass after fermentation by 1.69–1.70 lg(CFU/mL) was recorded. The obtained data indicate that Lactobacillus delbrueckii subsp. bulgaricus holds promise for the fermentation of red rice-based beverages with extracts exhibiting adaptogenic properties, with rhodiola and basil with rosemary being the most promising in terms of the overall set of parameters. The relevance of the study is due to the global trend of transition to plant-based alternatives to animal products: it is predicted that by 2026 the global plant-based "milk" market will reach $21 billion USD, which necessitates the development of new lactose-free fermented products. The work employed a comprehensive approach, including determination of pH dynamics, maximum acidification rate (Vmax), total polyphenol content by the Folin–Ciocalteu method, antioxidant activity by the DPPH method, and microbial viability by the pour plate method on MRS medium. Differences in acidification kinetics were established: the Eleutherococcus sample was characterized by the maximum acidification rate (0.275 pH units/h), while rosemary demonstrated the lowest Vmax (0.210 pH units/h). A differentiated relationship between polyphenol content and antioxidant activity was revealed: rosemary showed an intermediate polyphenol content (0.107 mg GAE/mL) with relatively high AOA (68.97%), indicating qualitative differences in the composition of antioxidant compounds. From an organoleptic point of view, the most harmonious flavor and aroma profile was noted for samples with basil and rosemary, which determines their potential for the development of mass-consumption products. The practical significance of the work lies in substantiating the possibility of creating a lactose-free fermented beverage of plant origin with adaptogenic properties and in identifying two strategic directions for further development: maximum functional profile (Rhodiola) and optimal organoleptic characteristics (basil and rosemary).

1. Egorova E.Yu. "Non-dairy milk": a review of raw materials and technologies. Polzunovsky Bulletin. 2019. no. 3. pp. 25–34. doi: 10.25712/ASTU.2072-8921.2018.03.005 (in Russian).

2. Apostolidis E., Kwon Y.I., Shetty K. Inhibitory potential of herb, fruit, and fungal-enriched cheese against key enzymes linked to type 2 diabetes and hypertension. Innovative Food Science & Emerging Technologies. 2007. vol. 8. no. 1. pp. 46–54. doi: 10.1016/j.ifset.2006.06.001.

3. Aydar E.F. Kidney bean (Phaseolus vulgaris L.) milk substitute as a novel plant-based drink: fatty acid profile, antioxidant activity, in-vitro phenolic bio-accessibility and sensory characteristics. Innovative Food Science & Emerging Technologies. 2023. vol. 83. article 103254. doi: 10.1016/j.ifset.2022.103254.

4. Bezerra M.F., Souza D.F.S., Correia R.T.P. Acidification kinetics, physicochemical properties and sensory attributes of yoghurts prepared from mixtures of goat and buffalo milks. International Journal of Dairy Technology. 2012. vol. 65. no. 3. pp. 437–443. doi: 10.1111/j.1471-0307.2012.00842.x.

5. Caccialanza A. How retail marketing levers influence demand for plant-based products: a revealed preference analysis across food categories and urbanization levels. British Food Journal. 2026. vol. 128. no. 3. pp. 1209–1234. doi: 10.1108/BFJ-05-2025-0483.

6. Cardinali F. Innovative fermented beverages made with red rice, barley, and buckwheat. Foods. 2021. vol. 10. no. 3. article 613. doi: 10.3390/foods10030613.

7. Chen T. Anthocyanins-natural pigment of colored rice bran: composition and biological activities. Food Research International. 2024. vol. 175. article 113722. doi: 10.1016/j.foodres.2023.113722.

8. Colombari Filho J.M., De Abreu A.G., Pereira J.A. Red Rice. In: Costa De Oliveira A., Pegoraro C., Ebeling Viana V. (eds.) The Future of Rice Demand: Quality Beyond Productivity. Cham: Springer International Publishing, 2020. pp. 283–296. doi: 10.1007/978-3-030-37510-2_12.

9. Deziderio M.A. Plant-Based Fermented Beverages: development and characterization. Foods. 2023. vol. 12. no. 22. article 4128. doi: 10.3390/foods12224128.

10. Fan M. Germination-induced changes in anthocyanins and proanthocyanidins: a pathway to boost bioactive compounds in red rice. Food Chemistry. 2024. vol. 433. article 137283. doi: 10.1016/j.foodchem.2023.137283.

11. Gunaratne A., Wu K., Li D. et al. Antioxidant activity and nutritional quality of traditional red-grained rice varieties containing proanthocyanidins. Food Chemistry. 2013. vol. 138. no. 2–3. pp. 1153–1161. doi: 10.1016/j.foodchem.2012.11.129.

12. Jukonyte R., Zavistanaviciute P., Lele V. et al. A potential of brown rice polish as a substrate for the lactic acid and bioactive compounds production by the lactic acid bacteria newly isolated from cereal-based fermented products. LWT. 2018. vol. 97. pp. 323–331. doi: 10.1016/j.lwt.2018.07.008.

13. Jun H., Lee J., Kim J. et al. Antioxidant activities and phenolic compounds of pigmented rice bran extracts. Journal of Food Science. 2012. vol. 77. no. 7. [Online first]. doi: 10.1111/j.1750-3841.2012.02786.x.

14. Kang S.J., Kim S.H., Lee J.H. et al. Bioactive compounds and quality evaluation of red-pigmented rice processed by germination and roasting. Foods. 2022. vol. 11. no. 18. article 2735. doi: 10.3390/foods11182735.

15. Laokuldilok T., Shoemaker C.F., Jongkaewwattana S., Tulyathan V. Antioxidants and antioxidant activity of several pigmented rice brans. Journal of Agricultural and Food Chemistry. 2011. vol. 59. no. 1. pp. 193–199. doi: 10.1021/jf103649q.

16. Li B., Hayes J.E., Ziegler G.R. Just-about-right and ideal scaling provide similar insights into the influence of sensory attributes on liking. Food Quality and Preference. 2014. vol. 37. pp. 71–78. doi: 10.1016/j.foodqual.2014.04.019.

17. Malekijahan F. Unlocking nature's potential: the power of adaptogens in enhancing modern health and wellness. Journal of Agriculture and Food Research. 2025. vol. 24. article 102501. doi: 10.1016/j.jafr.2025.102501.

18. Panossian A., Lemerond T. Two sides of the same coin for health: adaptogenic botanicals as nutraceuticals for nutrition and pharmaceuticals in medicine. Pharmaceuticals. 2025. vol. 18. no. 9. article 1346. doi: 10.3390/ph18091346.

19. Rodríguez-Roque M.J., Rojas-Graü M.A., Elez-Martínez P., Martín-Belloso O. Soymilk phenolic compounds, isoflavones and antioxidant activity as affected by in vitro gastrointestinal digestion. Food Chemistry. 2013. vol. 136. no. 1. pp. 206–212. doi: 10.1016/j.foodchem.2012.07.115.

20. Roland N., Chassard C., Gaucheron F. et al. Benefits of fermented foods, from empiricism to scientific evidence: the contribution of Ferments du Futur. Cahiers de Nutrition et de Diététique. 2026. [Online first]. doi: 10.1016/j.cnd.2026.03.004.

21. Shao Y., Xu F., Sun X. et al. Phenolic acids, anthocyanins, and antioxidant capacity in rice (Oryza sativa L.) grains at four stages of development after flowering. Food Chemistry. 2014. vol. 143. pp. 90–96. doi: 10.1016/j.foodchem.2013.07.113.

22. Stanley-Foreman Z. Plant milks are pushing for further innovation in specialty coffee. 2025.

23. Yu J., Yu X., Wang Y. et al. Changes of polyphenols and their antioxidant activities in non-pigmented, red and black rice during in vitro digestion. Food Chemistry: X. 2024. vol. 24. article 101821. doi: 10.1016/j.fochx.2024.101821.

24. Popova N.V. Evaluation of the effectiveness of the fermentation process of rice milk with a complex probiotic starter culture. In: Science of SUSU: Proceedings of the 75th Scientific Conference. Sections of Natural Sciences. Chelyabinsk: SUSU, 2023. pp. 19–21. (in Russian).

25. Boyarineva I.V., Derkanosova N.M., Vasilenko O.A. et al. Investigation of the biochemical activity of starter compositions enriched with propionic acid bacteria on various raw materials. Proceedings of the Voronezh State University of Engineering Technologies. 2023. vol. 85. no. 1. pp. 180–186. doi: 10.20914/2310-1202-2023-1-180-186.

26. Irondi E.A., Adegoke B.M., Alamu E.O. et al. Plant-based milk substitutes: sources, production, and nutritional, nutraceutical and sensory qualities. Frontiers in Food Science and Technology. 2025. vol. 5. article 1593870. doi: 10.3389/frfst.2025.1593870.

27. Meta H., Sokra I., Somaly S. Comparative review of hedonic, descriptive, and discrimination sensory tests. 2026. vol.2. pp. 287–297. doi: 10.6084/m9.figshare.30937733.