Several epidemiologic studies have found that consuming fruits and vegetables lowers the risk of getting a variety of chronic illnesses, including several types of cancers, cardiovascular diseases (CVDs), and bowel diseases. Although there is still debate over the bioactive components, various secondary plant metabolites have been linked to these positive health benefits. Many of these features have recently been connected to carotenoids and their metabolites’ effects on intracellular signalling cascades, which influence gene expression and protein translation. Carotenoids are the most prevalent lipid-soluble phytochemicals in the human diet, are found in micromolar amounts in human serum, and are very susceptible to multiple oxidation and isomerisation reactions. The gastrointestinal delivery system, digestion processes, stability, and functionality of carotenoids, as well as their impact on the gut microbiota and how carotenoids may be effective modulators of oxidative stress and inflammatory pathways, are still lacking research advances. Although several pathways involved in carotenoids’ bioactivity have been identified, future studies should focus on the carotenoids’ relationships, related metabolites, and their effects on transcription factors and metabolism.

Given the health risks associated with synthetic colorants, natural pigments have emerged as a promising alternative. These renewable choices not only provide health benefits but also offer valuable technical and sensory properties to food systems. The effective application of natural colorants, however, requires the optimization of processing conditions, exploration of new sources, and development of novel formulations to ensure stability and maintain their inherent qualities. Several natural pigment sources have been explored to achieve the broad color range desired by consumers. The purpose of this review is to explore the current advances in the obtention and utilization of natural pigments derived from by-products, which possess health-enhancing properties and are extracted through environmentally friendly methods. Moreover, this review provides new insights into the extraction processes, applications, and bioactivities of different types of pigments.

Carotenoids, prominent lipid-soluble phytochemicals in the human diet, are responsible for vibrant colours in nature and play crucial roles in human health. While they are extensively studied for their antioxidant properties and contributions to vitamin A synthesis, their interactions with the intestinal microbiota (IM) remain poorly understood. In this study, beta (β)-carotene, lutein, lycopene, a mixture of these three pigments, and the alga Osmundea pinnatifida were submitted to simulated gastrointestinal digestion (GID) and evaluated on human faecal samples. The results showed varying effects on IM metabolic dynamics, organic acid production, and microbial composition. Carotenoid exposure influenced glucose metabolism and induced the production of organic acids, notably succinic and acetic acids, compared with the control. Microbial composition analysis revealed shifts in phyla abundance, particularly increased Pseudomonadota. The α-diversity indices demonstrated higher diversity in β-carotene and the pigments’ mixture samples, while the β-diversity analysis indicated significant dissimilarity between the control and the carotenoid sample groups. UPLC-qTOF MS analysis suggested dynamic changes in carotenoid compounds during simulated fermentation, with lutein exhibiting distinct mass ion fragmentation patterns. This comprehensive research enhances our understanding of carotenoid-IM interactions, shedding light on potential health implications and the need for tailored interventions for optimal outcomes.

Background/Objectives: Carotenoids are bioactive pigments with well-established antioxidant and immunomodulatory properties, yet their impact on gut microbiota remains poorly understood from a chemical standpoint. This study explores how carotenoid structure and gastrointestinal stability shape microbial responses combining in vitro fermentation with bioinformatic analyses. Methods: Individual carotenoids (beta (β)-carotene, lutein, lycopene) and combined carotenoids, as well as algal-derived extracts were subjected to 48 h in vitro fermentation, and microbial composition and activity were assessed through sequencing and computational analysis. Results: β-carotene and lycopene promoted acid-tolerant taxa such as Escherichia-Shigella, whereas lutein, due to its higher polarity, supported more transient fluctuations. Mixtures and algal carotenoids exhibited synergistic effects, sustaining beneficial genera including Bifidobacterium and Bacteroides and promoting structured ecological trajectories. Conclusions: These findings provide a chemistry-driven perspective on how carotenoids act as modulators of microbial ecosystems, with direct implications for the formulation of carotenoid-enriched functional foods and dietary interventions.

Biomaterials have been extensively researched for various potential biomedical uses, like medication delivery, biosensors, wound healing, tissue engineering, implantable devices, and cosmetic products. Natural polymers offer benefits such as biodegradability and biocompatibility; however, they often exhibit lower mechanical strength than synthetic materials. Conversely, synthetic polymers face challenges like high cytotoxicity and diminished biocompatibility. Biopolymers consist of monomer units linked together by covalent interactions. Pectin, an anionic heteropolysaccharide soluble in water, is predominantly extracted from the plant cell walls, particularly citrus fruits, employing chemical or enzyme-based processes. It can also be sourced from agricultural by-products, making it a sustainable option with a positive environmental impact. Additionally, pectin shows substantial promise in biomedical applications owing to its safety, affordability, and anti-inflammatory effects. Scientists are increasingly interested in pectin because of its unique medical properties, and its uses are likely to expand due to growing research interest. This chapter provides a comprehensive summary of pectin-based biopolymers explicitly derived from food by-products, discusses the extraction methods, explores their potential as sustainable materials for advanced biomedical applications, and examines their impact on sustainability and the environment.