carotenoid

Overview

Carotenoids are a large and structurally diverse class of lipophilic pigments biosynthesized primarily by plants, algae, fungi, and photosynthetic bacteria. Comprising over 750 identified structures, they are subdivided into two principal groups: carotenes, which are pure hydrocarbons (such as β-carotene and lycopene), and xanthophylls, which are oxygenated derivatives (such as lutein, zeaxanthin, and astaxanthin). Their characteristic conjugated polyene backbone renders them potent light-absorbing chromophores, contributing pigmentation ranging from yellow and orange to deep red in fruits, vegetables, and biological tissues. In plants, carotenoids serve as accessory photosynthetic pigments and photoprotective agents; in animals and humans, they fulfill critical roles as precursors to vitamin A (retinoids), lipid-soluble antioxidants, and modulators of immune function. Their capacity to quench singlet oxygen and neutralize reactive oxygen species underpins their well-established role in mitigating oxidative stress, a process implicated in the pathogenesis of cardiovascular disease, Malignant Disease, and metabolic dysfunction–associated steatotic liver disease.

Beyond their antioxidant function, carotenoids interact with a range of intracellular signaling cascades. They have been shown to modulate the PI3K/AKT/mTOR pathway and influence sirtuin 1 activity, positioning them as regulators of cellular energy homeostasis and autophagy. Their inhibitory effects on enzymes such as alpha-glucosidase and amylase alpha 1C underscore their relevance in glycemic control, while interactions with butyrylcholinesterase suggest a neuroprotective dimension. As fat-soluble molecules, their bioavailability is inherently dependent on co-ingested lipids, food matrix properties, and processing conditions—factors that have driven substantial recent research into encapsulation and delivery technologies.

Focus of Latest Publications

Recent publications have examined carotenoids in several nutritional, analytical, and delivery contexts. In the Environmental Determinants of Diabetes in the Young study, carotenoid intake and plasma carotenoid status were assessed alongside retinol and tocopherol measures to investigate associations with the development of islet autoimmunity and progression to type 1 diabetes. A separate review on microalgal biotechnology highlighted carotenoid production as a promising application area for microalgae, particularly in the hot-dry valley regions of southwest China.

Several studies focused on carotenoids in food matrices and their bioaccessibility. In quinoa, in vitro digestion of bitter and nonbitter genotypes showed that saponins did not alter the digestive stability, solubility, bioaccessibility, or micellar efficiency of carotenoids and tococochromanols. In another study, modified mango cotyledon starch was used to microencapsulate a carotenoid-rich pumpkin suspension, and the resulting fortified foods showed matrix-dependent carotenoid bioaccessibility, with yogurt providing the highest bioaccessibility and a 200 mL serving contributing substantially to vitamin A recommended dietary allowance across age groups. Similarly, food-grade bigels based on agar hydrogels and carnauba wax oleogels were developed as carriers for carotenoid-rich extracts from Arthrospira platensis and Scenedesmus obliquus; both hydrogel:oleogel ratio and 3D printing affected digestive stability, micellization, and bioaccessibility, with xanthophyll-rich systems generally performing better than carotene-rich systems.

Other publications explored carotenoids as bioactive constituents in plant extracts and by-product valorization. Leaf extracts from eight fruit tree species were profiled for chlorophylls and carotenoids, and multivariate analysis indicated that carotenoids were associated with antidiabetic activity, while chlorophyll derivatives correlated more strongly with antioxidant and neuroprotective effects. In cherry juice, carotenoids were implicated in aroma formation pathways, alongside pyruvic acid, Amino Acids, and fatty acids. Red guava by-products were also used to extract and nanoencapsulate pulp carotenoids, with peel and seed materials serving as wall components; the resulting nanoparticles showed antioxidant activity, good encapsulation performance, and storage stability, supporting potential use as a liquid dietary supplement dye.

Across these studies, carotenoids were also discussed in broader reviews of natural products and health. One review described carotenoids among bioactive compounds that can modulate autophagy through pathways including AMPK, PI3K/AKT/mTOR, sirtuin 1, and FOXO, with relevance to aging and age-related disease. Overall, the recent literature emphasizes carotenoids as nutritionally important compounds, as targets for improving bioaccessibility and delivery, and as bioactive constituents with potential roles in food, nutraceutical, and health applications.

Key Publications

NEWJul Retinol, Carotenoid, and Tocopherol Intake and Status, and the Risk of Islet Autoimmunity and Type 1 Diabetes: The Environmental Determinants of Diabetes in the Young Study. (Diabetes/metabolism research and reviews, 2026, PMID 42361128): "To study the associations of dietary intake of A and E vitamins, as well as plasma retinols, carotenoids, and tocopherols in relation to development of islet autoimmunity and progression to T1D."
NEWJun Advantages and prospects of developing microalgal industry in hot-dry valley regions of China. (Sheng wu gong cheng xue bao = Chinese journal of biotechnology, 2026, PMID 42343794): "It further elaborates on the promising prospects of microalgal biotechnology in key areas such as the production of carotenoids, the treatment of animal farming wastewater, and the manufacture of future human food products."
May Saponins Do Not Impede the Bioaccessibility of Minerals and Fat-Soluble Vitamins from Different Quinoa Genotypes. (Journal of agricultural and food chemistry, 2026, PMID 42030452): "In conclusion, the saponins in quinoa do not appear to affect micellar characteristics or to impair the bioaccessibility of minerals, carotenoids, and tocochromanols."
May Comprehensive profiling of chlorophylls, carotenoids extracts and their derivatives in leaves of fruit tree species and assessment of antioxidant and enzyme inhibitory activities. (Food chemistry, 2026, PMID 41861736): "This study aimed to characterize the profiles and evaluate the bioactivity potential of chlorophyll- and carotenoid-rich extracts (Ch&C.Ex) obtained from the leaves of eight fruit tree species."
May Exploring aroma descriptions of different cherry juice and the mechanism of aroma formation in Lapins using volatilomics and machine learning. (Food chemistry, 2026, PMID 41861739): "The mechanism of aroma formation was analyzed, which involved the metabolism of pyruvic acid, amino acids, fatty acids and carotenoids."
May Enhancing carotenoid bioaccessibility in food matrices using modified mango cotyledon starch microcapsules: Contribution to the recommended daily intake. (Food chemistry, 2026, PMID 41855840): "The resulting microcapsules were incorporated into water, yogurt, and gelatin to develop carotenoid-fortified foods."
Apr Mechanistic Modulation of Autophagy by Bioactive Natural Products: Implications for Human Aging and Longevity. (Nutrients, 2026, PMID 41830033): "Natural compounds like polyphenols, flavonoids, alkaloids, terpenoids, and carotenoids exhibit dual roles by restoring age-related suppressed autophagic flux and inhibiting excessive autophagy-induced cell death."
May Valorization of red guava by-products: Nanoencapsulation of pulp carotenoids with peel and seed for a liquid dietary supplement dye. (Food chemistry, 2026, PMID 41812448): "This study explored the integral use of imperfect red guava by extracting carotenoids from the pulp, employing the peel and seed as natural wall materials for nanoencapsulation."
May Carotenoid bioaccessibility in food-grade Bigels: Impact of hydrogel:Oleogel ratio and 3D printing. (Food chemistry, 2026, PMID 41740380): "In A. platensis, micellar fractions contained both carotenes and xanthophylls, while S. obliquus extracts were dominated by xanthophylls (>90%)."