University of Guilan Caspian Journal of Environmental Sciences 1735-3033 24 3 2026 07 01 Response surface methodology-optimized ultrasound-assisted extraction of zeaxanthin and lutein from maize grain and husk, beet tops, and bilberry leaves 783 796 9791 10.22124/cjes.2026.9791 EN Laila Kalimoldina Department of Chemistry, Chemical Technology and Ecology, Almaty Technological University; Almaty, Tole bi St., 100, 050012, Kazakhstan Saule Alamagambetova Department of Chemistry, Chemical Technology and Ecology, Almaty Technological University; Almaty, Tole bi St., 100, 050012, Kazakhstan Lazzat Seitmagazimova Department of Chemistry, Chemical Technology and Ecology, Almaty Technological University; Almaty, Tole bi St., 100, 050012, Kazakhstan Zura Yessimsiitova Al-Farabi Kazakh National University, 71 al-Farabi Avenue, Almaty, 050040 Mariya Suleimenova Department of Chemistry, Chemical Technology and Ecology, Almaty Technological University; Almaty, Tole bi St., 100, 050012, Kazakhstan Dauren Mukhanov Al-Farabi Kazakh National University, 71 al-Farabi Avenue, Almaty, 050040 Assiya Nuraly Department of Chemistry, Chemical Technology and Ecology, Almaty Technological University; Almaty, Tole bi St., 100, 050012, Kazakhstan Alibek Mutushev Department of Chemistry, Chemical Technology and Ecology, Almaty Technological University; Almaty, Tole bi St., 100, 050012, Kazakhstan Dauren Baiseitov Faculty of Natural Sciences and Geography, Abai Kazakh National University, Dostyk Avenue, 13, Almaty 050010, Kazakhstan Madina Zhetenova Department of Chemistry, Chemical Technology and Ecology, Almaty Technological University; Almaty, Tole bi St., 100, 050012, Kazakhstan Journal Article 2026 07 29 Lutein and zeaxanthin are valuable xanthophyll carotenoids with recognized antioxidant activity and important roles in ocular protection. The development of efficient and sustainable extraction methods from underutilized plant materials is therefore of considerable interest for food, nutraceutical, and pharmaceutical applications. In this study, ultrasound-assisted extraction (UAE) was optimized for the recovery of lutein- and zeaxanthin-containing extracts from selected agricultural byproducts, including maize grain and husk fractions, beet tops, and bilberry leaves/berries. Response surface methodology with a central composite design was applied to evaluate the effects of extraction temperature, extraction time, and solid-to-solvent ratio on carotenoid recovery. Conventional solvent extraction was used as a control. The optimized UAE process substantially reduced extraction time from 3–4 h to 35–40 min and increased the recovery of target bioactive compounds by approximately 30–42% compared with conventional extraction. The improvement was attributed to ultrasound-enhanced matrix disruption, improved solvent penetration, and intensified mass transfer. Functional and technological characterization showed that ultrasound treatment decreased bulk density and increased water-holding capacity, oil-holding capacity, swelling capacity, and hydration-related properties of the plant powders, indicating improved accessibility of the plant matrix. FTIR spectroscopy confirmed the presence of characteristic functional groups associated with xanthophyll-containing extracts, including O–H, aliphatic C–H, conjugated C=C, and C–O vibrations, without evidence of pronounced structural degradation under the selected extraction conditions. The results demonstrate that UAE is an efficient, rapid, and environmentally favorable approach for producing carotenoid-rich extracts from locally available agro-industrial residues. This method may support the valorization of plant byproducts into functional ingredients for nutraceutical, food, cosmetic, and potential ophthalmological applications. https://cjes.guilan.ac.ir/article_9791_b9e76d5b7b2152b280806b62d0e50302.pdf