Emulsion templated microencapsulation of dandelion (Taraxacum officinale L.) polyphenols and β-carotene by ionotropic gelation of alginate and pectin

Background Bioresidues valorization has gained a pivotal relevance in the last years, directly moved by consumers' demands for heathier and safer products (food, cosmetics, supplements, drugs, and so on) and by industrial companies that need to adapt their manufacturing procedures to increasingly strict regulatory guidelines. Most of the natural ingredients are considered more sought and safer than synthetic ones, but also more expensive and less abundant. Therefore, the recovery of valuable active ingredients from wastes and by-products may be an interesting and upcoming strategy. Scope and approach The present report aims to provide an extensive approach to bioresidues valorization, focusing its chemical composition in terms of carotenoids content and their upcoming uses for biotechnological purposes. Key findings and conclusions Daily produced and discharged industrial bioresidues derived from vegetable (peel, seeds, pericarp) and animal (wastewater, crustacean's cephalothorax and carapace, scales, tails) sources comprise the richest sources of carotenoids (carotenes and xanthophylls). Different techniques are commonly used for carotenoids recovery being the extraction with organic solvents the most frequently used. Supercritical fluid extraction, microwave- and enzyme-assisted extractions are applied, but mainly in combination. This area opens fascinating opportunities to discover and to design novel strategies for carotenoids production/accumulation, foodstuffs valorization and provide valuable ingredients to different industrial sectors.

Wastes and by-products: Upcoming sources of carotenoids for biotechnological purposes and health-related applications

Organoselenium-catalyzed selectivity-switchable oxidation of β-ionone

Provitamin A biofortification, the provision of provitamin A carotenoids through agriculture, is regarded as an effective and sustainable intervention to defeat vitamin A deficiency, representing a global health problem. This food-based intervention has been questioned in conjunction with negative outcomes for smokers and asbestos-exposed populations of the CARET and ATBC trials in which very high doses of β-carotene were supplemented. The current notion that β-carotene cleavage products (apocarotenoids) represented the harmful agents is the basis of the here-presented research. We quantitatively analyzed numerous plant food items and concluded that neither the amounts of apocarotenoids nor β-carotene provided by plant tissues, be they conventional or provitamin A-biofortified, pose an increased risk. We also investigated β-carotene degradation pathways over time. This reveals a substantial nonenzymatic proportion of carotene decay and corroborates the quantitative relevance of highly oxidized β-carotene ...

Nonenzymatic β-Carotene Degradation in Provitamin A-Biofortified Crop Plants.

The net amounts of carotenoids accumulating in plant tissues are determined by the rates of biosynthesis and degradation. While biosynthesis is rate-limited by the activity of PHYTOENE SYNTHASE (PSY), carotenoid losses are caused by catabolic enzymatic and non-enzymatic degradation. We established a system based on non-green Arabidopsis callus which allowed investigating major determinants for high steady-state levels of β-carotene. Wild-type callus development was characterized by strong carotenoid degradation which was only marginally caused by the activity of carotenoid cleavage oxygenases. In contrast, carotenoid degradation occurred mostly non-enzymatically and selectively affected carotenoids in a molecule-dependent manner. Using carotenogenic pathway mutants, we found that linear carotenes such as phytoene, phytofluene and pro-lycopene resisted degradation and accumulated while β-carotene was highly susceptible towards degradation. Moderately increased pathway activity through PSY overexpression was compensated by degradation revealing no net increase in β-carotene. However, higher pathway activities outcompeted carotenoid degradation and efficiently increased steady-state β-carotene amounts to up to 500 μg g-1 dry mass. Furthermore, we identified oxidative β-carotene degradation products which correlated with pathway activities, yielding β-apocarotenals of different chain length and various apocarotene-dialdehydes. The latter included methylglyoxal and glyoxal as putative oxidative end products suggesting a potential recovery of carotenoid-derived carbon for primary metabolic pathways. Moreover, we investigated the site of β-carotene sequestration by co-localization experiments which revealed that β-carotene accumulated as intra-plastid crystals which was confirmed by electron microscopy with carotenoid-accumulating roots. The results are discussed in the context of using the non-green calli carotenoid assay system for approaches targeting high steady-state β-carotene levels prior to their application in crops.

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Establishment of an Arabidopsis callus system to study the interrelations of biosynthesis, degradation and accumulation of carotenoids.

Carotenoids are reported to have immunological effects independent of vitamin A activity. Although antioxidant activity has been suggested as a basis of action, the ability of carotenoids to autoxi...

β-Carotene autoxidation: oxygen copolymerization, non-vitamin A products, and immunological activity

In animals carotenoids show biological activity unrelated to vitamin A that has been considered to arise directly from the behavior of the parent compound, particularly as an antioxidant. However, the very property that confers antioxidant activity on some carotenoids in plants also confers susceptibility to oxidative transformation. As an alternative, it has been suggested that carotenoid oxidative breakdown or metabolic products could be the actual agents of activity in animals. However, an important and neglected aspect of the behavior of the highly unsaturated carotenoids is their potential to undergo addition of oxygen to form copolymers. Recently we reported that spontaneous oxidation of s-carotene transforms it into a product dominated by s-carotene-oxygen copolymers. We now report that the polymeric product is biologically active. Results suggest an overall ability to prime innate immune function to more rapidly respond to subsequent microbial challenges. An underlying structural resemblance to sporopollenin, found in the outer shell of spores and pollen, may allow the polymer to modulate innate immune responses through interactions with the pattern recognition receptor system. Oxygen copolymer formation appears common to all carotenoids, is anticipated to be widespread, and the products may contribute to the health benefits of carotenoid-rich fruits and vegetables.

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Biologically active polymers from spontaneous carotenoid oxidation: a new frontier in carotenoid activity.

We reported previously that the spontaneous oxidation of β-carotene and other carotenoids proceeds predominantly by formation of carotenoid-oxygen copolymers and that β-carotene copolymers exhibit immunological activity, including priming innate immune function and limiting inflammatory processes. Oxidative loss of carotenoids in fruits and vegetables occurs during processing. Here we report evidence for the occurrence of associated analogous copolymer compounds. Geronic acid, an indirect, low molecular weight marker of β-carotene oxidation at ∼2% of β-carotene copolymers, is found to occur in common fresh or dried foods, including carrots, tomatoes, sweet potatoes, paprika, rosehips, seaweeds, and alfalfa, at levels encompassing an approximately thousand-fold range, from low ng/g in fresh foods to μg/g in dried foods. Copolymers isolated from several dried foods reach mg/g levels: comparable to initial carotenoid levels. In vivo biological activity of supplemental β-carotene copolymers has been previousl...

Discovery and Characterization of Carotenoid-Oxygen Copolymers in Fruits and Vegetables with Potential Health Benefits

β-Carotene oxidation products - Function and safety.

β-carotene spontaneously copolymerizes with molecular oxygen to form a β-carotene–oxygen copolymer compound (“copolymer”) as the main product, together with small amounts of many apocarotenoids. Bo...

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Trevor J. Mogg

Papers

β-Carotene autoxidation: oxygen copolymerization, non-vitamin A products, and immunological activity

Biologically active polymers from spontaneous carotenoid oxidation: a new frontier in carotenoid activity.

Discovery and Characterization of Carotenoid-Oxygen Copolymers in Fruits and Vegetables with Potential Health Benefits

β-Carotene oxidation products - Function and safety.

The β-carotene–oxygen copolymer: its relationship to apocarotenoids and β-carotene function