Investigating the bioactive properties of spearmint, orange peel, and salvia microphylla oleoresins extracted via supercritical CO2: anti-obesogenic, antioxidant, anti-Inflammatory, and neuroprotective effects and their integration into dark chocolate

Abstract

Oleoresins, with their potential health benefits, hold promise as functional ingredients, but there is scarce scientific information on their bioactivities and applications. This thesis focused on characterizing and assessing the anti-obesogenic, antioxidant, anti-inflammatory, and neuroprotective properties of spearmint (SP-O), orange peel (OP-O), and Salvia microphylla (SM-O) oleoresins extracted using supercritical CO2. These oleoresins were subsequently incorporated into dark chocolate, and their impact on physicochemical and sensory properties was evaluated. Dehydrated leaves of SP and SM, and OP were ground and subjected to supercritical CO2 extraction (2,200 psi, 8 hrs, 40°C). The extracts were characterized for carotenoid and phenolic compound composition through liquid chromatography and volatile compounds using gas chromatography. Emulsions (SP-E, SM-E, OP-E) were prepared using Tween 80 (3:1; v/v) to homogenize both fractions (oleoresin and aromatic water) present in the crude extract, and their anti-obesogenic, antioxidant, anti-inflammatory, and neuroprotective properties were evaluated in vitro with 3T3-L1, Caco-2, Raw 265.7, and SH-SY5Y cell lines, respectively. Furthermore, dark chocolate was added with these oleoresin emulsions, and their impact on water activity, color, texture, rheology, and sensory properties were assessed. The results indicated that these oleoresins are rich sources of phenolic compounds, carotenoids, and volatile compounds. SP-O was abundant in vanillin, all-trans-β-carotene, and linolenic acid. In the case of OP-O, the major compounds identified were t-cinnamic acid, all-trans-β-carotene, and D-limonene. Moreover, SM-O was rich in podophyllotoxin, all-trans-β-carotene and pulegone. In vitro studies suggested that SP-E, OP-E, and SM-E exhibited the ability to inhibit both reactive oxygen species (ROS) by 80%, 51%, 37%, respectively and nitric oxide (NO) production by 48%, 43%, 48%, respectively. Only OP-E displayed neuroprotective effects. Both SM-E and OP-E inhibited lipid accumulation by 30% and 25%, respectively. When fortified with these emulsions, the chocolate formulations exhibited softer texture, lower water activity, and a solid-like behavior. Notably, the OP-E formulation received the highest sensory preference. In summary, these oleoresins hold potential as nutraceutical agents for mitigating the development of metabolic syndrome and its associated pathologies, given their demonstrated anti-obesogenic, anti-inflammatory, antioxidant, and neuroprotective attributes. Furthermore, incorporating these emulsified oleoresins into chocolate matrices presents a viable strategy for the formulation of functional foods; nevertheless, further research is needed to elucidate both preventive and therapeutic efficacy within these fortified chocolates.