Functional Properties of Carotenoids in Human Health

Antheraxanthin: Insights delving from biosynthesis to processing effects

Antheraxanthin (C40H56O3) is one of fat-soluble carotenoids belonging to natural pigments. Its chemical structure is based on the unsaturated polyene chain skeleton, with a hydroxy-β-ionone ring and an epoxy-β-ionone ring on each side of the skeleton. It is found in a wide range of plants and photosynthetic bacteria, and external stimuli (high temperature, drought, ozone treatment, etc.) can significantly affect its synthesis. It also, like other carotenoids, exhibits a diverse potential pharmacological profile as well as nutraceutical values. However, it is worth noting that various food processing methods (extrusion, puffing, baking, etc.) and storage conditions for fruits and vegetables have distinct impacts on the bioaccessibility and retention of antheraxanthin. This compilation of antheraxanthin includes sources, biosynthesis, chemical analysis, and processing effects.

The role of carotenoids in bone health-A narrative review

Osteoporosis constitutes a serious challenge for public health. Dietary patterns belong to important, modifiable risk factors of this disease. Therefore, what and in what quantities we consume on a daily basis are extremely relevant. It is commonly known that bone health is positively affected by vitamins (e.g., vitamin D and vitamin K) as well as mineral components (e.g., calcium and magnesium). However, the human diet consists of many other groups of compounds that exhibit a potential antiosteoporotic and supporting bone-building effect. These dietary components include carotenoids. This paper presents a broad review of studies on the influence of particular carotenoids (β-carotene, lutein, zeaxanthin, β-cryptoxanthin, and lycopene) on bones. The paper discusses up-to-date in vitro experiments and research on animal models and presents how the results translate into clinical effect in humans.

Macular Pigment Optical Density and Skin Carotenoids in a Childhood Sample

BACKGROUND

Carotenoids are plant pigments with light filtering and antioxidant properties that deposit in human tissues, including retina and skin. Descriptive characteristics and covariates of carotenoid status in macula and skin have been examined in adults; however, similar studies in children are limited. Thus, this study aimed to delineate how factors of age, sex, race, weight status, and dietary carotenoid intake relate to macular and skin carotenoids in children.

METHODS

Children (7-13 y, N = 375) completed heterochromatic flicker photometry to assess macular pigment optical density (MPOD). Participants underwent anthropometrics to measure weight status (BMI percentile [BMI%]), and parent/guardian provided demographic information. Subsample data were available for skin carotenoids (N = 181), assessed using reflection spectroscopy, and dietary carotenoids (N = 101) using the Block Food Frequency Questionnaire. Relationships between skin and macular carotenoids were assessed using partial Pearson's correlations controlling for age, sex, race, and BMI%. Relationships between dietary carotenoids and macular and skin carotenoids were assessed using stepwise linear regression including age, sex, race, and BMI% in the model.

RESULTS

Mean MPOD was 0.56 ± 0.22 and skin carotenoid score was 282 ± 94.6. There was no significant correlation between MPOD and skin carotenoids (r = 0.02, P = 0.76). BMI% was negatively associated with skin (stdβ = -0.42, P < 0.001), but not macular carotenoids (stdβ = -0.04, P = 0.70). Neither MPOD nor skin carotenoids were associated with age, sex, or race (all P > 0.10). MPOD was positively associated with energy-adjusted reported lutein + zeaxanthin intake (stdβ = 0.27, P = 0.01). Skin carotenoids were positively associated with energy-adjusted reported carotenoid intake (stdβ = 0.26, P = 0.01).

CONCLUSIONS

The mean MPOD values in children were higher than what has been reported in adult populations. Previous studies in adult samples report an average MPOD of 0.21. Although macular and skin carotenoids were not related, they were associated with dietary carotenoids relevant to the respective tissues; however, skin carotenoids may be more susceptible negative influence from higher weight status.

Explicating genetic architecture governing nutritional quality in pigmented rice

Rice is one of the most important staple plant foods that provide a major source of calories and nutrients for tackling the global hunger index especially in developing countries. In terms of nutritional profile, pigmented rice grains are favoured for their nutritional and health benefits. The pigmented rice varieties are rich sources of flavonoids, anthocyanin and proanthocyanidin that can be readily incorporated into diets to help address various lifestyle diseases. However, the cultivation of pigmented rice is limited due to low productivity and unfavourable cooking qualities. With the advances in genome sequencing, molecular breeding, gene expression analysis and multi-omics approaches, various attempts have been made to explore the genetic architecture of rice grain pigmentation. In this review, we have compiled the current state of knowledge of the genetic architecture and nutritional value of pigmentation in rice based upon the available experimental evidence. Future research areas that can help to deepen our understanding and help in harnessing the economic and health benefits of pigmented rice are also explored.

Optimization of carotenoid production by Umbelopsis ramanniana

Umbelopsis ramanniana was investigated to increase carotenoid production. Nine different carbon sources and six different nitrogen sources were evaluated for the maximum carotenoid production. The most effective nitrogen and carbon sources were KNO3 and lactose, respectively. Then, the optimization of medium components for enhancement of carotenoid production by Umbelopsis ramanniana was achieved using Plackett-Burman design. Box-Behnken response surface methodology was applied to further optimize carotenoid and biomass production. Carbon to nitrogen ratio, lactose concentration, and shaking speed were studied as variables in Box-Behnken design. The optimum conditions for carotenoid and biomass production were determined as 32.42 g/L of lactose concentration, 20:1 of carbon to nitrogen ratio, and shaking speed of 130 rpm. The maximum carotenoid and biomass production under optimized conditions were 1141 μg/L (β-carotene-Eq) and 13.14 g/L, respectively. When compared to the control fermentation, carotenoid, and biomass production were increased by about 2 and 1.3 folds, respectively.

Integrated metabolome and transcriptome analyses provide insight into the effect of red and blue LEDs on the quality of sweet potato leaves

Red and blue light-emitting diodes (LEDs) affect the quality of sweet potato leaves and their nutritional profile. Vines cultivated under blue LEDs had higher soluble protein contents, total phenolic compounds, flavonoids, and total antioxidant activity. Conversely, chlorophyll, soluble sugar, protein, and vitamin C contents were higher in leaves grown under red LEDs. Red and blue light increased the accumulation of 77 and 18 metabolites, respectively. Alpha-linoleic and linolenic acid metabolism were the most significantly enriched pathways based on Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. A total of 615 genes were differentially expressed between sweet potato leaves exposed to red and blue LEDs. Among these, 510 differentially expressed genes were upregulated in leaves grown under blue light compared with those grown under red light, while the remaining 105 genes were expressed at higher levels in the latter than in the former. Among the KEGG enrichment pathways, blue light significantly induced anthocyanin and carotenoid biosynthesis structural genes. This study provides a scientific reference basis for using light to alter metabolites to improve the quality of edible sweet potato leaves.

Industrially Important Fungal Carotenoids: Advancements in Biotechnological Production and Extraction

Carotenoids are lipid-soluble compounds that are present in nature, including plants and microorganisms such as fungi, certain bacteria, and algae. In fungi, they are widely present in almost all taxonomic classifications. Fungal carotenoids have gained special attention due to their biochemistry and the genetics of their synthetic pathway. The antioxidant potential of carotenoids may help fungi survive longer in their natural environment. Carotenoids may be produced in greater quantities using biotechnological methods than by chemical synthesis or plant extraction. The initial focus of this review is on industrially important carotenoids in the most advanced fungal and yeast strains, with a brief description of their taxonomic classification. Biotechnology has long been regarded as the most suitable alternative way of producing natural pigment from microbes due to their immense capacity to accumulate these pigments. So, this review mainly presents the recent progress in the genetic modification of native and non-native producers to modify the carotenoid biosynthetic pathway for enhanced carotenoid production, as well as factors affecting carotenoid biosynthesis in fungal strains and yeast, and proposes various extraction methods to obtain high yields of carotenoids in an attempt to find suitable greener extraction methods. Finally, a brief description of the challenges regarding the commercialization of these fungal carotenoids and the solution is also given.

Microalgae Produce Antioxidant Molecules with Potential Preventive Effects on Mitochondrial Functions and Skeletal Muscular Oxidative Stress

In recent years, microalgae have become a source of molecules for a healthy life. Their composition of carbohydrates, peptides, lipids, vitamins and carotenoids makes them a promising new source of antioxidant molecules. Skeletal muscle is a tissue that requires constant remodeling via protein turnover, and its regular functioning consumes energy in the form of adenosine triphosphate (ATP), which is produced by mitochondria. Under conditions of traumatic exercise or muscular diseases, a high production of reactive oxygen species (ROS) at the origin of oxidative stress (OS) will lead to inflammation and muscle atrophy, with life-long consequences. In this review, we describe the potential antioxidant effects of microalgae and their biomolecules on mitochondrial functions and skeletal muscular oxidative stress during exercises or in musculoskeletal diseases, as in sarcopenia, chronic obstructive pulmonary disease (COPD) and Duchenne muscular dystrophy (DMD), through the increase in and regulation of antioxidant pathways and protein synthesis.

Chemistry, Occurrence, Properties, Applications, and Encapsulation of Carotenoids-A Review

Carotenoids are natural lipophilic pigments and antioxidants that are present in many fruits and vegetables. The consumption of carotenoids is correlated with positive health effects and a decreased risk of several chronic diseases. Provitamin A carotenoids (β-carotene, α-carotene, γ-carotene, and β-cryptoxanthin) are essential for the development and maintenance of sight. β-carotene, α-carotene, zeaxanthin, β-cryptoxanthin, lutein, and lycopene have high antioxidant activity and promote free radical scavenging, which helps protect against chronic diseases. However, carotenoids are chemically unstable and prone to oxidation in the presence of light, heat, oxygen, acids, and metal ions. The use of carotenoids in the food industry is limited due to their poor solubility in water, bioavailability and quick release. Encapsulation techniques, such as microencapsulation, nanoencapsulation and supercritical encapsulation, are used to overcome these problems. The objective of this paper is to describe the characteristics and potential health benefits of carotenoids and advances in encapsulation techniques for protecting and enhancing their solubility or bioavailability.

Elucidation of the potential antioxidant compound and mechanism of mung bean using network pharmacology and in vitro anti-oxidative activity

Mung bean is rich in bioactive components, but the main compound and pharmacological mechanism in reducing oxidative and free radical damage are unclear. Network pharmacology and 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical scavenging activities were employed to uncover the antioxidant mechanism of potentially active compounds, considering the interactions between mung bean targets and oxidative and free radical damage. These key targets were analyzed by protein–protein interactions (PPIs), and key genes were used to find the biological pathway and therapeutic mechanism by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. The results showed that five antioxidant components and 18 mung bean targets were screened. β-carotene and vitexin both played a crucial role in mung bean against oxidative and free radical damage, and the ABTS radical scavenging activities of β-carotene and vitexin were 94.84 and 87.79%, which were equivalent to those of vitamin C. Key targets may be AR, HSP90AA1, MYC, and CASP3 for mung bean to exert antioxidant activity. GO and KEGG indicated that mung bean may mainly act on thyroid hormone signaling pathway, estrogen signaling pathway, p53 signaling pathway, etc. In vitro antioxidant activity tests showed that the bioactive ingredients of mung beans had great antioxidant activity. Network pharmacology analysis also revealed the underlying molecular mechanisms of oxidative and free radical damage. This study provides new insights and evidence to explore the bioactive compounds and biological functions of food cereals and legumes, as well as a reference for the functional evaluation of food ingredients and the development of functional foods.

Antioxidant Potential and Capacity of Microorganism-Sourced C30 Carotenoids-A Review

Carotenoids are lipophilic tetraterpenoid pigments produced by plants, algae, arthropods, and certain bacteria and fungi. These biologically active compounds are used in the food, feed, and nutraceutical industries for their coloring and the physiological benefits imparted by their antioxidant properties. The current global carotenoid market is dominated by synthetic carotenoids; however, the rising consumer demand for natural products has led to increasing research and development in the mass production of carotenoids from alternative natural sources, including microbial synthesis and plant extraction, which holds a significant market share. To date, microbial research has focused on C₄₀ carotenoids, but studies have shown that C₃₀ carotenoids contain similar—and in some microbial strains, greater—antioxidant activity in both the physical and chemical quenching of reactive oxygen species. The discovery of carotenoid biosynthetic pathways in different microorganisms and advances in metabolic engineering are driving the discovery of novel C₃₀ carotenoid compounds. This review highlights the C₃₀ carotenoids from microbial sources, showcasing their antioxidant properties and the technologies emerging for their enhanced production. Industrial applications and tactics, as well as biotechnological strategies for their optimized synthesis, are also discussed.

Unraveling the Effects of Carotenoids Accumulation in Human Papillary Thyroid Carcinoma

Among the thyroid cancers, papillary thyroid cancer (PTC) accounts for 90% of the cases. In addition to the necessity to identify new targets for PTC treatment, early diagnosis and management are highly demanded. Previous data indicated that the multivariate statistical analysis of the Raman spectra allows the discrimination of healthy tissues from PTC ones; this is characterized by bands typical of carotenoids. Here, we dissected the molecular effects of carotenoid accumulation in PTC patients by analyzing whether they were required to provide increased retinoic acid (RA) synthesis and signaling and/or to sustain antioxidant functions. HPLC analysis revealed the lack of a significant difference in the overall content of carotenoids. For this reason, we wondered whether the carotenoid accumulation in PTC patients could be related to vitamin A derivative retinoic acid (RA) biosynthesis and, consequently, the RA-related pathway activation. The transcriptomic analysis performed using a dedicated PCR array revealed a significant downregulation of RA-related pathways in PTCs, suggesting that the carotenoid accumulation in PTC could be related to a lower metabolic conversion into RA compared to that of healthy tissues. In addition, the gene expression profile of 474 PTC cases previously published in the framework of the Cancer Genome Atlas (TGCA) project was examined by hierarchical clustering and heatmap analyses. This metanalysis study indicated that the RA-related pathways resulted in being significantly downregulated in PTCs and being associated with the follicular variant of PTC (FV-PTC). To assess whether the possible fate of the carotenoids accumulated in PTCs is associated with the oxidative stress response, the expression of enzymes involved in ROS scavenging was checked. An increased oxidative stress status and a reduced antioxidant defense response were observed in PTCs compared to matched healthy thyroids; this was possibly associated with the prooxidant effects of high levels of carotenoids. Finally, the DepMap datasets were used to profile the levels of 225 metabolites in 12 thyroid cancer cell lines. The results obtained suggested that the high carotenoid content in PTCs correlates with tryptophan metabolism. This pilot provided novel possible markers and possible therapeutic targets for PTC diagnosis and therapy. For the future, a larger study including a higher number of PTC patients will be necessary to further validate the molecular data reported here.

Comparative Transcriptome Analysis Identified Key Pathways and Genes Regulating Differentiated Stigma Color in Melon (Cucumis melo L.)

Stigma color is an important morphological trait in many flowering plants. Visual observations in different field experiments have shown that a green stigma in melons is more attractive to natural pollinators than a yellow one. In the current study, we evaluated the characterization of two contrasted melon lines (MR-1 with a green stigma and M4-7 with a yellow stigma). Endogenous quantification showed that the chlorophyll and carotenoid content in the MR-1 stigmas was higher compared to the M4-7 stigmas. The primary differences in the chloroplast ultrastructure at different developmental stages depicted that the stigmas of both melon lines were mainly enriched with granum, plastoglobulus, and starch grains. Further, comparative transcriptomic analysis was performed to identify the candidate pathways and genes regulating melon stigma color during key developmental stages (S1–S3). The obtained results indicated similar biological processes involved in the three stages, but major differences were observed in light reactions and chloroplast pathways. The weighted gene co-expression network analysis (WGCNA) of differentially expressed genes (DEGs) uncovered a “black” network module (655 out of 5302 genes), mainly corresponding to light reactions, light harvesting, the chlorophyll metabolic process, and the chlorophyll biosynthetic process, and exhibited a significant contribution to stigma color. Overall, the expression of five key genes of the chlorophyll synthesis pathway—CAO (MELO03C010624), CHLH (MELO03C007233), CRD (MELO03C026802), HEMA (MELO03C011113), POR (MELO03C016714)—were checked at different stages of stigma development in both melon lines using quantitative real time polymerase chain reaction (qRT-PCR). The results exhibited that the expression of these genes gradually increased during the stigma development of the MR-1 line but decreased in the M4-7 line at S2. In addition, the expression trends in different stages were the same as RNA-seq, indicating data accuracy. To sum up, our research reveals an in-depth molecular mechanism of stigma coloration and suggests that chlorophyll and related biological activity play an important role in differentiating melon stigma color.

Astaxanthin Bioactivity Is Determined by Stereoisomer Composition and Extraction Method

Astaxanthin (ASX) is a natural product and one of the most powerful antioxidants known. It has significant effects on the metabolism of many animals, increasing fecundity, egg yolk volume, growth rates, immune responses, and disease resistance. A large part of the bioactivity of ASX is due to its targeting of mitochondria, where it inserts itself into cell membranes. Here, ASX stabilizes membranes and acts as a powerful antioxidant, protecting mitochondria from damage by reactive oxygen species (ROS). ROS are ubiquitous by-products of energy metabolism that must be tightly regulated by cells, lest they bind to and inactivate proteins, DNA and RNA, lipids, and signaling molecules. Most animals cannot synthesize ASX, so they need to acquire it in their diet. ASX is easily thermally denatured during extraction, and its high hydrophobicity limits its bioavailability. Our focus in this review is to contrast the bioactivity of different ASX stereoisomers and how extraction methods can denature ASX, compromising its bioavailability and bioactivity. We discuss the commercial sources of astaxanthin, structure of stereoisomers, relative bioavailability and bioactivity of ASX stereoisomers, mechanisms of ASX bioactivity, evolution of carotenoids, and why mitochondrial targeting makes ASX such an effective antioxidant.

Engineering a photosynthetic bacteria-incorporated hydrogel for infected wound healing

Treating wounds with multidrug-resistant bacterial infections remains a huge and arduous challenge. In this work, we prepared a "live-drug"-encapsulated hydrogel dressing for the treatment of multidrug-resistant bacterial infections and full-thickness skin incision repair. Our live dressing was comprised of photosynthetic bacteria (PSB) and extracellular matrix (ECM) gel with photothermal, antibacterial and antioxidant properties, as well as good cytocompatibility and blood compatibility. More interestingly, live PSB could be regarded as not only photothermal agents but also as anti-inflammatory agents to promote wound healing owing to their antioxidant metabolites. In vitro and in vivo studies showed that the PSB hydrogel not only had a high killing rate against methicillin-resistant Staphylococcus aureus (MRSA) but it also accelerated collagen deposition and granulation tissue formation by promoting cell proliferation and migration, which significantly promoted skin tissue regeneration and wound healing. We believe that the large-scale production of PSB Gel-based therapeutic dressings has the advantages of easy use and promising clinical applications. STATEMENT OF SIGNIFICANCE: Rapid wound healing and the treatment of bacterial infections have always been the two biggest challenges in the field of wound care. We prepared a "live drug" dressing by encapsulating photosynthetic bacteria into an extracellular matrix hydrogel to sterilize the wound and promote wound healing. First, photosynthetic bacteria are not only a photothermal agent for photothermal wound sterilization, but also possess the anti-inflammatory capacity to enhance wound healing due to their antioxidant metabolites. Second, the extracellular matrix hydrogel is rich in a variety of growth factors and nutrients to promote cell migration and accelerate wound healing. Third, photosynthetic bacteria are not only green and non-toxic, but also can be obtained on a large scale, which facilitates manufacturing and clinical transformation.

Bacterial Carotenoids: Extraction, Characterization, and Applications

Natural carotenoids are secondary metabolites that exhibit antioxidant, anti-inflammatory, and anti-cancer properties. These types of compounds are highly demanded by pharmaceutical, cosmetic, nutraceutical, and food industries, leading to the search for new natural sources of carotenoids. In recent years, the production of carotenoids from bacteria has become of great interest for industrial applications. In addition to carotenoids with C40-skeletons, some bacteria have the ability to synthesize characteristic carotenoids with C30-skeletons. In this regard, a great variety of methodologies for the extraction and identification of bacterial carotenoids has been reported and this is the first review that condenses most of this information. To understand the diversity of carotenoids from bacteria, we present their biosynthetic origin in order to focus on the methodologies employed in their extraction and characterization. Special emphasis has been made on high-performance liquid chromatography-mass spectrometry (HPLC-MS) for the analysis and identification of bacterial carotenoids. We end up this review showing their potential commercial use. This review is proposed as a guide for the identification of these metabolites, which are frequently reported in new bacteria strains.

Influence of soil amendment of different concentrations of amino acid water-soluble fertilizer on physiological characteristics, yield and quality of "Hangjiao No.2" Chili Pepper

Amino acids are well known as natural stimulators of plant growth and are widely used to promote crop yield and quality. Several studies have been conducted to investigate the effects of amino acid (s) as a foliar spray on a variety of plant species. However, the effects of soil amendment of different concentrations of amino acid water-soluble fertilizer on the physiological characteristics, yield, and quality of pepper remain unclear. Following this, three experimental sets of amino acid water-soluble fertilizer in the ratio 1.8: 2.7: 3.6 kg including control (CK) were conducted in Lintao county, Gansu province. The treatments were applied through furrow method at 6 weeks after planting. The results showed that physiological characteristics of the pepper plants, such as chlorophyll a (1.35 mg g⁻¹), and b (0.67 mg g⁻¹), total chlorophyll (2.02 mg g⁻¹), carotenoid (0.63 mg g⁻¹), ETR (26.25 µmol m⁻²s⁻¹), Fv/Fm (0.75), Qp (0.92) contents of the leaves were increased by the 1.8 kg treatment while NPQ (71.37%) and root activity (2185.52 µg g⁻¹ h⁻¹) were improved by the 3.6 kg treatment compared to the control. Fertilization with 2.7 kg of amino acid water-soluble fertilizer also had a significant influence on fruit length (25.50 cm), and yield of pepper (37.92 t ha⁻¹) while fruit diameter (24.51 mm), firmness (5.30 kg cm⁻²), fresh (48.10 g) and dry (4.71 g) weights were higher in the 1.8 kg treatment compared to the control. The lowest rate of fertilizer (1.8 kg) applied again resulted in a significant increase in soluble protein (79.79%), capsaicin (5.80 mg g⁻¹), dihydrocapsaicin (1.08 mg g⁻¹), vitamin C (72.33%) and the essential and non-essential amino acid contents of the pepper which ranged from (235.15 to 11.16 µg g⁻¹) and (1,605.10 to 16.63 µg g⁻¹) respectively, while soluble sugar (9.02%) was enhanced by 3.6 kg treatment compared to the control. The findings suggest that soil amendment with low concentration of amino acid water-soluble fertilizer (1.8 kg) could be successfully used to improve the physiological characteristics and fruit quality of peppers in vegetable production.

Genetic Modification of Mucor circinelloides for Canthaxanthin Production by Heterologous Expression of β-carotene Ketolase Gene

Canthaxanthin is a reddish-orange xanthophyll with strong antioxidant activity and higher bioavailability than carotenes, primarily used in food, cosmetics, aquaculture, and pharmaceutical industries. The spiking market for natural canthaxanthin promoted researchers toward genetic engineering of heterologous hosts for canthaxanthin production. Mucor circinelloides is a dimorphic fungus that produces β-carotene as the major carotenoid and is considered as a model organism for carotenogenic studies. In this study, canthaxanthin-producing M. circinelloides strain was developed by integrating the codon-optimized β-carotene ketolase gene (bkt) of the Haematococcus pluvialis into the genome of the fungus under the control of strong promoter zrt1. First, a basic plasmid was constructed to disrupt crgA gene, a negative regulator of carotene biosynthesis resulted in substantial β-carotene production, which served as the building block for canthaxanthin by further enzymatic reaction of the ketolase enzyme. The genetically engineered strain produced a significant amount (576 ± 28 μg/g) of canthaxanthin, which is the highest amount reported in Mucor to date. Moreover, the cell dry weight of the recombinant strain was also determined, producing up to more than 9.0 g/L, after 96 h. The mRNA expression level of bkt in the overexpressing strain was analyzed by RT-qPCR, which increased by 5.3-, 4.1-, and 3-folds at 24, 48, and 72 h, respectively, compared with the control strain. The canthaxanthin-producing M. circinelloides strain obtained in this study provided a basis for further improving the biotechnological production of canthaxanthin and suggested a useful approach for the construction of more valuable carotenoids, such as astaxanthin.

Encapsulation of Lutein via Microfluidic Technology: Evaluation of Stability and In Vitro Bioaccessibility

Inadequate intake of lutein is relevant to a higher risk of age-related eye diseases. However, lutein has been barely incorporated into foods efficiently because it is prone to degradation and is poorly bioaccessible in the gastrointestinal tract. Microfluidics, a novel food processing technology that can control fluid flows at the microscale, can enable the efficient encapsulation of bioactive compounds by fabricating suitable delivery structures. Hence, the present study aimed to evaluate the stability and the bioaccessibility of lutein that is encapsulated in a new noodle-like product made via microfluidic technology. Two types of oils (safflower oil (SO) and olive oil (OL)) were selected as a delivery vehicle for lutein, and two customized microfluidic devices (co-flow and combination-flow) were used. Lutein encapsulation was created by the following: (i) co-flow + SO, (ii) co-flow + OL, (iii) combination-flow + SO, and (iv) combination-flow + OL. The initial encapsulation of lutein in the noodle-like product was achieved at 86.0 ± 2.7%. Although lutein’s stability experienced a decreasing trend, the retention of lutein was maintained above 60% for up to seven days of storage. The two types of device did not result in a difference in lutein bioaccessibility (co-flow: 3.1 ± 0.5%; combination-flow: 3.6 ± 0.6%) and SO and OL also showed no difference in lutein bioaccessibility (SO: 3.4 ± 0.8%; OL: 3.3 ± 0.4%). These results suggest that the types of oil and device do not affect the lutein bioaccessibility. Findings from this study may provide scientific insights into emulsion-based delivery systems that employ microfluidics for the encapsulation of bioactive compounds into foods.

An Updated Comprehensive Review on Vitamin A and Carotenoids in Breast Cancer: Mechanisms, Genetics, Assessment, Current Evidence, and Future Clinical Implications

Vitamin A and carotenoids are fat-soluble micronutrients that play important role as powerful antioxidants modulating oxidative stress and cancer development. Breast cancer is the most common malignancy in women. As the risk of breast cancer is dependent on various lifestyle factors such as dietary modifications, there is increasing interest surrounding the anti-cancerous properties of vitamin A and carotenoids. Despite the suggested protective roles of vitamin A and carotenoids in breast cancer development, their clinical application for the prevention and treatment of breast cancer is limited. In this narrative review, we discuss the roles of vitamin A and carotenoids along with the evaluation method of vitamin A status. We also exhibit the association of genetic variations involved in metabolism of vitamin A and carotenoids with cancers and other diseases. We demonstrate the epidemiological evidence for the relationship of vitamin A and carotenoids with breast cancer risk, their effects on cancer mechanism, and the recent updates in clinical practice of vitamin A or carotenoids as a potential therapeutic agent against breast cancer. This review provides insight into the preventive and therapeutic roles of vitamin A and carotenoids in breast cancer development and progression.

Combination of red and blue light induces anthocyanin and other secondary metabolite biosynthesis pathways in an age-dependent manner in Batavia lettuce

Lettuce is commonly consumed around the world, spurring the cultivation of green- and red-leaf varieties in indoor farms. One common consideration for indoor cultivation is the light wavelengths/spectrum, which is an important factor for regulating growth, development, and the accumulation of metabolites. Here, we show that Batavia lettuce (Lactuca sativa cv. "Batavia") grown under a combination of red (R) and blue (B) light (RB, R:B = 3:1) displayed better growth and accumulated more anthocyanin than lettuce grown under fluorescent light (FL). Anthocyanin concentration was also higher in mature stage than early stage lettuce. By performing a comparative transcriptome analysis of early and mature stage lettuce grown under RB or FL (RB or FL-lettuce), we found that RB induced the expression of genes related to oxidation-reduction reaction and secondary metabolite biosynthesis. Furthermore, plant age affected the transcriptome response to RB, as mature RB-lettuce had six times more differentially expressed genes than early RB-lettuce. Also, genes related to the accumulation of secondary metabolites such as flavonoids and anthocyanins were more induced in mature RB-lettuce. A detailed analysis of the anthocyanin biosynthesis pathway revealed key genes that were up-regulated in mature RB-lettuce. Concurrently, branching pathways for flavonol and lignin precursors were down-regulated.

Lutein Has a Positive Impact on Brain Health in Healthy Older Adults: A Systematic Review of Randomized Controlled Trials and Cohort Studies

A previous systematic review revealed that lutein intake leads to improved cognitive function among older adults. However, the association between lutein intake and brain health remains unclear.

METHODS

We searched the Web of Science, PubMed, PsycInfo, and Cochrane Library for research papers. The criteria were (1) an intervention study using oral lutein intake or a cross-sectional study that examined lutein levels and the brain, (2) participants were older adults, and (3) brain activities or structures were measured using a brain imaging technique (magnetic resonance imaging (MRI) or electroencephalography (EEG)).

RESULTS

Seven studies using MRI (brain activities during rest, cognitive tasks, and brain structure) and two studies using EEG were included. We mainly focused on MRI studies. Three intervention studies using MRI indicated that 10 mg lutein intake over 12 months had a positive impact on healthy older adults' brain activities during learning, resting-state connectivity, and gray matter volumes. Four cross-sectional studies using MRI suggested that lutein was positively associated with brain structure and neural efficiency during cognitive tasks.

CONCLUSION

Although only nine studies that used similar datasets were reviewed, this systematic review indicates that lutein has beneficial effects on healthy older adults' brain health.

Dietary Intake and Circulating Concentrations of Carotenoids and Risk of Type 2 Diabetes: A Dose-Response Meta-Analysis of Prospective Observational Studies

Previous meta-analysis studies have indicated inverse associations between some carotenoids and risks of metabolic syndrome, cardiovascular disease, cancer, and all-cause mortality. However, the results for associations between carotenoids and type 2 diabetes (T2D) remain inconsistent and no systematic assessment has been done on this topic. We conducted a systematic review and meta-analysis to examine the associations of dietary intakes and circulating concentrations of carotenoids with risk of T2D. We searched PubMed and Ovid Embase from database inception to July 2020. Prospective observational studies of carotenoids and T2D risk were included. Random-effects models were used to summarize the RRs and 95% CIs. Thirteen publications were included. Dietary intake of β-carotene was inversely associated with the risk of T2D, and the pooled RR comparing the highest with the lowest categories was 0.78 (95% CI: 0.70, 0.87; I2 = 13.7%; n = 6); inverse associations were also found for total carotenoids (n = 2), α-carotene (n = 4), and lutein/zeaxanthin (n = 4), with pooled RRs ranging from 0.80 to 0.91, whereas no significant associations were observed for β-cryptoxanthin and lycopene. Circulating concentration of β-carotene was associated with a lower risk of T2D, and the pooled RR comparing extreme categories was 0.60 (95% CI: 0.46, 0.78; I2 = 56.2%; n = 7); inverse associations were also found for total carotenoids (n = 3), lycopene (n = 4), and lutein (n = 2), with pooled RRs ranging from 0.63 to 0.85, whereas no significant association was found for circulating concentrations of α-carotene and zeaxanthin when comparing extreme categories. Dose-response analysis indicated that nonlinear relations were observed for circulating concentrations of α-carotene, β-carotene, lutein, and total carotenoids (all P-nonlinearity < 0.05), but not for other carotenoids or dietary exposures. In conclusion, higher dietary intakes and circulating concentrations of total carotenoids, especially β-carotene, were associated with a lower risk of T2D. More studies are needed to confirm the causality and explore the role of foods rich in carotenoids in prevention of T2D. This systematic review was registered at www.crd.york.ac.uk/prospero as CRD42020196616.

Effect of photoperiod on vitamin E and carotenoid biosynthesis in mung bean (Vigna radiata) sprouts

Light affects the accumulation of vitamin E and carotenoids in many crops. This study investigated the impact of photoperiods on the metabolic regulation of vitamin E and carotenoids in mung bean sprouts considering their dietary health benefits. Mung beans were germinated under three different photoperiods: constant light, semilight and constant dark. Results revealed that the semilight photoperiod was optimum for vitamin E and carotenoid accumulation in mung bean sprouts. DXS was activated in the constant dark and was inhibited by constant light. GGPPS and HPT were sensitive to semilight photoperiod in the vitamin E biosynthetic pathway, playing dominant roles in vitamin E accumulation. The PSY, LCYE, LUT5, LUT1 and ZE genes, which are associated with carotenoid biosynthesis, were activated under semilight treatment and significantly regulated the accumulation of carotenoids. This knowledge improves knowledge on light-mediated regulation of vitamin E and carotenoids in mung bean sprouts.

Egg Quality from Nera Atriana, a Local Poultry Breed of the Abruzzo Region (Italy), and ISA Brown Hens Reared under Free Range Conditions

The selection and diffusion in the poultry sector of hybrid breeds able to produce higher amount of meat and eggs, led over time to the erosion of genetic resources. One of the strategies that can be applied in order to stem such phenomenon, concerns the valorization of the animal products, meat or eggs, obtained from indigenous poultry breeds. Therefore, the aim of this study is to characterize the qualitative aspects of eggs obtained from the Nera Atriana hen, an Italian indigenous laying hen characteristic of the Abruzzo region, making a direct comparison with a commercial hybrid reared in the same environment and applying the same feeding protocol. The trial was conducted for a period of 5 months (from March to July 2019), in which 6 egg samplings were performed (one at the beginning and additional 5 on a monthly basis); each sampling involved the collection of 15 eggs per group of animals for a total of 90 eggs per genotype. Eggs were specifically subjected to evaluations of the physical parameters, including the yolk color, and analyses aimed at determining the content of total lipids, cholesterol, and β-carotene. In addition to this, the fatty acids profile and the electrophoretic pattern of the globular proteins of the yolk were characterized. Eggs from hybrid hens were characterized by higher total weight with significantly higher values specifically associated to albumen and yolk weight and to the albumen percentage. In the eggs obtained from the local hen, higher relative percentages were instead found in the quantity of shell and yolk; furthermore, in the same samples was observed a higher yolk redness, a cholesterol concentration tending to be lower although not significant (p = 0.0521), and a greater amount of saturated fatty acids which could justify a lower susceptibility of the food to oxidative processes following transformation with heat treatments. With regard to the fatty acid composition, differences were specifically observed for palmitic (C16:0) and palmitoleic (C16:1 cis-9) acids that showed higher relative percentages in eggs from local breed, and for the oleic acid (C18:1 cis-9) which was more represented in eggs from commercial hens. In conclusion, some interesting nutritional features, in a preliminary way, have been highlighted that could lead the consumer to prefer these "niche" products over those obtained from commercial hybrids.

β-Carotene: Preventive Role for Type 2 Diabetes Mellitus and Obesity: A Review

Carotenoids are vital antioxidants for plants and animals. They protect cells from oxidative events and act against the inflammatory process and carcinogenesis. Among the most abundant carotenoids in human and foods is β-carotene. This carotenoid has the highest level of provitamin A activity, as it splits into two molecules of retinol through the actions of the cytosolic enzymes: β-carotene-15,15′-monooxygenase (β-carotene-15,15′-oxygenase 1) and β-carotene-9′,10′-dioxygenase (β-carotene-9′,10′-oxygenase 2). The literature supports the idea that β-carotene acts against type 2 diabetes mellitus, cardiovascular diseases, obesity, and metabolic syndrome. Due to the many processes involved in β-carotene biosynthesis and metabolic function, little is known about such components, since many mechanisms have not yet been fully elucidated. Therefore, our study concisely described the relationships between the consumption of carotenoids, with emphasis on β-carotene, and obesity and type 2 diabetes mellitus and its associated parameters in order to understand the preventive role of carotenoids better and encourage their consumption.

Astaxanthin as a new Raman probe for biosensing of specific subcellular lipidic structures: can we detect lipids in cells under resonance conditions?

Here we report a new Raman probe for cellular studies on lipids detection and distribution. It is (3S, 3'S)-astaxanthin (AXT), a natural xanthophyll of hydrophobic properties and high solubility in lipids. It contains a chromophore group, a long polyene chain of eleven conjugated C=C bonds including two in the terminal rings, absorbing light in the visible range that coincides with the excitation of lasers commonly used in Raman spectroscopy for studying of biological samples. Depending on the laser, resonance (excitation in the visible range) or pre-resonance (the near infrared range) Raman spectrum of astaxanthin is dominated by bands at ca. 1008, 1158, and 1520 cm⁻¹ that now can be also a marker of lipids distribution in the cells. We showed that AXT accumulates in lipidic structures of endothelial cells in time-dependent manner that provides possibility to visualize e.g. endoplasmic reticulum, as well as nuclear envelope. As a non-toxic reporter, it has a potential in the future studies on e.g. nucleus membranes damage in live cells in a very short measuring time.

Canthaxanthin, a Red-Hot Carotenoid: Applications, Synthesis, and Biosynthetic Evolution

Carotenoids are a class of pigments with a biological role in light capture and antioxidant activities. High value ketocarotenoids, such as astaxanthin and canthaxanthin, are highly appealing for applications in human nutraceutical, cosmetic, and animal feed industries due to their color- and health-related properties. In this review, recent advances in metabolic engineering and synthetic biology towards the production of ketocarotenoids, in particular the red-orange canthaxanthin, are highlighted. Also reviewed and discussed are the properties of canthaxanthin, its natural producers, and various strategies for its chemical synthesis. We review the de novo synthesis of canthaxanthin and the functional β-carotene ketolase enzyme across organisms, supported by a protein-sequence-based phylogenetic analysis. Various possible modifications of the carotenoid biosynthesis pathway and the present sustainable cost-effective alternative platforms for ketocarotenoids biosynthesis are also discussed.

New insights into red plant pigments: more than just natural colorants

Pigments make nature both colorful and attractive. Humans have always incorporated the natural pigments of fruits, vegetables and spices into their dietary requirements. Naturally occurring red pigments in plants are carotenoids, anthocyanins and betacyanins. Natural pigments, apart from colour, provide added properties and are therefore considered to be bioactive constituents. Red natural colorants are one of the most widely used in the food industry. The interest in these pigments lies in the enhancement of the healthy effects of the diet. In this context, attention is given to carotenoids, anthocyanins and betacyanins, with emphasis on the basic chemical and biochemical attributes and wide-ranging health-promoting benefits of these pigments. Thus, in this review, we systematically present the advantages and limitations of these natural pigments as food colorants in relation to their physico-chemical properties, reactivity and bioactivity.

Fish-based Bioactives as Potent Nutraceuticals: Exploring the Therapeutic Perspective of Sustainable Food from the Sea

Recent developments in nutraceuticals and functional foods have confirmed that bioactive components present in our diet play a major therapeutic role against human diseases. Moreover, there is a huge emphasis on food scientists for identifying and producing foods with better bioactive activity, which can ultimately provide wellness and well-being to human health. Among the several well-known foods with bioactive constituents, fish has always been considered important, due to its rich nutritional values and by-product application in food industries. Nutritionists, food scientists, and other scientific communities have been working jointly to uncover new bioactive molecules that could increase the potential and therapeutic benefits of these bioactive components. Despite the innumerable benefits of fish and known fish bioactive molecules, its use by food or pharmaceutical industries is scarce, and even research on fish-based nutraceuticals is not promising. Therefore, this review focuses on the current information/data available regarding fish bioactive components, its application as nutraceuticals for therapeutic purposes in the treatment of chronic diseases, ethnic issues related to consumption of fish or its by-products. Especial emphasis is given on the utilization of fish wastes and its by-products to fulfill the world demand for cheap dietary supplements specifically for underdeveloped/least developed countries.

Why is Zeaxanthin the Most Concentrated Xanthophyll in the Central Fovea?

Diet-based xanthophylls (zeaxanthin and lutein) are conditionally essential polar carotenoids preferentially accreted in high concentrations (1 mM) to the central retina, where they have the capacity to impart unique physiologically significant biophysical biochemical properties implicated in cell function, rescue, and survival. Macular xanthophylls interact with membrane-bound proteins and lipids to absorb/attenuate light energy, modulate oxidative stress and redox balance, and influence signal transduction cascades implicated in the pathophysiology of age-related macular degeneration. There is exclusive transport, sequestration, and appreciable bioamplification of macular xanthophylls from the circulating carotenoid pool to the retina and within the retina to regions required for high-resolution sensory processing. The distribution of diet-based macular xanthophylls and the lutein metabolite meso-zeaxanthin varies considerably by retinal eccentricity. Zeaxanthin concentrations are 2.5-fold higher than lutein in the cone-dense central fovea. This is an ~20-fold increase in the molar ratio relative to eccentric retinal regions with biochemically detectable macular xanthophylls. In this review, we discuss how the differences in the specific properties of lutein and zeaxanthin could help explain the preferential accumulation of zeaxanthin in the most vulnerable region of the macula.

CRISPR/Cas9 directed editing of lycopene epsilon-cyclase modulates metabolic flux for β-carotene biosynthesis in banana fruit

Banana is one of the most economically important fruit crops worldwide. Genetic improvement in banana is a challenging task due to its parthenocarpic nature and triploid genome. Genetic modification of crops via the CRISPR/Cas9 module has emerged as a promising tool to develop important traits. In the present work, a CRISPR/Cas9-based approach was used to develop the β-carotene-enriched Cavendish banana cultivar (cv.) Grand Naine (AAA genome). The fifth exon of the lycopene epsilon-cyclase (LCYε) gene was targeted. The targeting specificity of the designed guide-RNA was also tested by its ability to create indels in the LCYε gene at the A genome of cv. Rasthali (AAB genome). Sequence analysis revealed multiple types of indels in the genomic region of Grand Naine LCYε (GN-LCYε). Metabolic profiling of the fruit pulp of selected edited lines showed enhanced accumulation of β-carotene content up to 6-fold (~24 μg/g) compared with the unedited plants. These lines also showed either an absence or a drastic reduction in the levels of lutein and α-carotene, suggesting metabolic reprogramming, without any significant effect on the agro-morphological parameters. In addition, differential expression of carotenoid pathway genes was observed in the edited lines in comparison to unedited plants. Overall, this is the first report in banana to improve nutritional trait by using a precise genome editing approach.

Raman spectroscopic detection of carotenoids in cattle skin

Carotenoids, powerful anti-oxidants, play a significant role in protecting the skin from oxidation and help in balancing the redox status of skin. This study was aimed at investigating cattle skin to identify carotenoids in the lower epidermis (grain) and dermis (corium) layers for classification using Raman spectroscopy which is a powerful technique for the detection of carotenoids in cattle skin due to the strong resonance enhancement with 532 nm laser excitation. The spectral differences identified between these two layers were quantified by the univariate analysis of Raman peak heights and partial least squares (PLS) analysis. We compared the performance of the Raman spectroscopy method with the standard method, high performance liquid chromatography. The univariate analysis results demonstrated that the lower epidermis of the skin has a higher concentration of carotenoid than dermis using the carotenoid Raman peaks at 1151 cm⁻¹ and 1518 cm⁻¹. The carotenoid Raman intensity was linearly correlated with the total carotenoid concentration determined by standard HPLC methods. Partial Least Squares Regression analysis gives excellent results with R² = 0.99. Our results indicate that Raman spectroscopy is a potential tool to determine carotenoids in cattle skin with high precision.

The lower epidermis and dermis of cattle skin was investigated for the detection of carotenoids using Raman spectroscopy.

Carotenoids of Capsicum Fruits: Pigment Profile and Health-Promoting Functional Attributes

Pepper of the Capsicum species is a common ingredient in various food preparations by different cultures worldwide. The Capsicum is recognised by its five main domesticated species, namely Capsicum annuum, C. baccatum, C. chinense, C. frutescens and C. pubescens. The genetic diversity in Capsicum offers fruits in wide ranges of morphology and carotenoid profile. Carotenoids enhance the value of pepper from a nutritional standpoint, despite being commonly prized for the pharmacologically active pungent capsaicinoids. Carotenoids of pepper comprise mainly of the unique, powerful and highly stable capsanthin and capsoroubin, together with β-carotene, β-cryptoxanthin, lutein, zeaxanthin, antheraxanthin and violaxanthin. These carotenoids are present at diverse profile and varying levels, biosynthetically connected to the fruit maturity stages. This review describes the health-promoting functional attributes of the carotenoids that are mainly associated with their excellent role as lipophilic antioxidants. Capsicum as a great source of carotenoids is discussed in the aspects of main domesticated species, biosynthesis, pigment profile, antioxidant activity and safety. Findings from a number of in vitro, in vivo and clinical studies provided appreciable evidence on the protective effects of pepper’s carotenoids against degenerative diseases. Hence, pepper with its functional carotenoids might be recommended in health-promoting and disease preventing strategies.

Effects of Root Cooling on Plant Growth and Fruit Quality of Cocktail Tomato during Two Consecutive Seasons

Understanding the effects of root temperature on plant growth and key food components of horticultural crops under greenhouse conditions is important. Here, we assess the impact of root cooling on plant growth and fruit quality of two cocktail tomato cultivars (Lycopersicon esculentum cv “Amoroso” and cv “Delioso”) during the winter of 2017-2018 and the summer of 2018. Plants were grown hydroponically on rockwool under different root temperatures (16–27°C and 10°C) from the 2nd inflorescence to harvest inside the greenhouse. A root temperature of 10°C was controlled independently from air temperature (18–23°C in winter and 21–29°C in summer) by circulating cooling water. Reductions of marketable yield per plant (7.9–20.9%) in both cultivars were observed in response to root cooling in winter, but not significantly in summer. In most cases, root cooling had a positive effect on the functional quality (sugars, vitamin C, and carotenoids levels). In the case of “Delioso,” glucose concentration increased by 7.7–10.3%, vitamin C by 20–21%, and lycopene by 16.9–20.5% in both seasons. “Amoroso” exhibited only higher consistent values in glucose with increments between 6.9 and 7.8% in the two seasons. The levels of elements decreased by root cooling, with statistically significant reduction of N, P, S, and Fe by 12.1–15.7% in “Delioso” in winter and P and Zn by 9.1–22.2% in both cultivars in summer. Thus, manipulation of root temperature could be a feasible method to improve the overall fruit quality of cocktail tomato; however, this effect was also dependent on cultivars and other environmental factors.

All-trans Retinoic Acid as a Versatile Cytosolic Signal Modulator Mediated by CRABP1

All-trans retinoic acid (AtRA), an active metabolite of vitamin A, is recognized for its classical action as an endocrine hormone that triggers genomic effects mediated through nuclear receptors RA receptors (RARs). New evidence shows that atRA-mediated cellular responses are biphasic with rapid and delayed responses. Most of these rapid atRA responses are the outcome of its binding to cellular retinoic acid binding protein 1 (CRABP1) that is predominantly localized in cytoplasm and binds to atRA with a high affinity. This review summarizes the most recent studies of such non-genomic outcomes of atRA and the role of CRABP1 in mediating such rapid effects in different cell types. In embryonic stem cells (ESCs), atRA-CRABP1 dampens growth factor sensitivity and stemness. In a hippocampal neural stem cell (NSC) population, atRA-CRABP1 negatively modulates NSC proliferation and affects learning and memory. In cardiomyocytes, atRA-CRABP1 prevents over-activation of calcium-calmodulin-dependent protein kinase II (CaMKII), protecting heart function. These are supported by the fact that CRABP1 gene knockout (KO) mice exhibit multiple phenotypes including hippocampal NSC expansion and spontaneous cardiac hypertrophy. This indicates that more potential processes/signaling pathways involving atRA-CRABP1 may exist, which remain to be identified.

Selenium in Germinated Chickpea (Cicer arietinum L.) Increases the Stability of Its Oil Fraction

Selenium is an essential mineral in human nutrition. In order to assess its effect on the stability of chickpea oil, seeds were germinated and tested with different amounts of sodium selenite (0.0, 0.5, 1.0 and 2.0 mg/100g seeds) for four days. Oil was extracted from sprouted chickpea and its physical properties, fatty acid profile (FAME), oxidative stability index (OSI), lipase and lipoxygenase (LOX) activities, cellular antioxidant activity (CAA), and phenolics and carotenoids were assessed and compared to chickpea seed oil. The amount of chickpea oil and its acid value (AV) increased during germination. The OSI increased by 28%, 46% and 14% for 0.5, 1.0 and 2.0 mg/100g compared with non-selenium treated sprouts. Phenolics increased up to 36% and carotenoids reduced by half in germinated sprouts with and without selenium compared to seeds. Carotenoids increased by 16% in sprouts treated with 1.0 mg/100 g selenium compared to their counterparts without selenium. FAME was not affected by treatments but samples with the highest selenium concentration increased lipase activity by 19% and decreased lipoxygenase activity by 55% compared with untreated sprouts. The CAA of oils increased by 43% to 66% in all germinated treatments compared with seeds. Results suggest that Se-enriched chickpea sprouts could represent an excellent source of oil with a high OSI and CAA, associated with a reduction in LOX activity and an increase in phenolics, respectively.

Catalyzed Oxidation of Carotenoids by Lactoperoxidase in the Presence of Ethanol

The discovery of the lactoperoxidase system as a biocatalyst in milk was a landmark finding. The activation of this system using hydrogen peroxide (H₂O₂) raised hopes for oxidation of various organic substrates. The involvement of lactoperoxidase system in the catalyzed-oxidation of carotenoids in the whey proteins, and the effect of various solvents on carotenoids' oxidation reaction rate has been studied. However, there is no evidence for this reaction without the addition of oxidizing agents, such as peroxides. Here, we reveal that carotenoids are oxidized through the addition of just ethanol in the presence of lactoperoxidase. The oxidation of carotenoids through this exquisite strategy is ∼360 times faster than harnessing the lactoperoxidase system in whey proteins via the addition of hydrogen peroxide. Bearing in mind that ethanol is not an oxidizing agent, this observation suggests a potential paradigm shift in our understanding of lactoperoxidase and catalyzed oxidation in biochemical systems.

Insights into the role of bacteria in vitamin A biosynthesis: Future research opportunities

Significant efforts have been made to address the hidden hunger challenges due to iron, zinc, iodine, and vitamin A since the beginning of the 21st century. Prioritizing the vitamin A deficiency (VAD) disorders, many countries are looking for viable alternative strategies such as biofortification. One of the leading causes of VAD is the poor bioconversion of β-carotene into retinoids. This review is focused on the opportunities of bacterial biosynthesis of retinoids, in particular, through the gut microbiota. The proposed hypothesis starts with the premise that an animal can able to store and timely convert carotenoids into retinoids in the liver and intestinal tissues. This theory is experimental with many scientific insights. The syntrophic metabolism, potential crosstalk of bile acids, lipocalins and lipopolysaccharides of gut microbiota are reported to contribute significantly to the retinoid biosynthesis. The gut bacteria respond to these kinds of factors by genetic restructuring driven mainly by events like horizontal gene transfer. A phylogenetic analysis of β-carotene 15, 15'-mono (di) oxygenase enzymes among a selected group of prokaryotes and eukaryotes was carried out to validate the hypotheses. Shedding light on the probiotic strategies through non-genetically modified organism such as gut bacteria capable of synthesizing vitamin A would address the VAD disorders.

Lycopene and Vascular Health

Lycopene is a lipophilic, unsaturated carotenoid, found in red-colored fruits and vegetables, including tomatoes, watermelon, papaya, red grapefruits, and guava. The present work provides an up to date overview of mechanisms linking lycopene in the human diet and vascular changes, considering epidemiological data, clinical studies, and experimental data. Lycopene may improve vascular function and contributes to the primary and secondary prevention of cardiovascular disorders. The main activity profile of lycopene includes antiatherosclerotic, antioxidant, anti-inflammatory, antihypertensive, antiplatelet, anti-apoptotic, and protective endothelial effects, the ability to improve the metabolic profile, and reduce arterial stiffness. In this context, lycopene has been shown in numerous studies to exert a favorable effect in patients with subclinical atherosclerosis, metabolic syndrome, hypertension, peripheral vascular disease, stroke and several other cardiovascular disorders, although the obtained results are sometimes inconsistent, which warrants further studies focusing on its bioactivity.

No evidence that carotenoid pigments boost either immune or antioxidant defenses in a songbird

Dietary carotenoids have been proposed to boost immune system and antioxidant functions in vertebrate animals, but studies aimed at testing these physiological functions of carotenoids have often failed to find support. Here we subject yellow canaries (Serinus canaria), which possess high levels of carotenoids in their tissue, and white recessive canaries, which possess a knockdown mutation that results in very low levels of tissue carotenoids, to oxidative and pathogen challenges. Across diverse measures of physiological performance, we detect no differences between carotenoid-rich yellow and carotenoid-deficient white canaries. These results add further challenge to the assumption that carotenoids are directly involved in supporting physiological function in vertebrate animals. While some dietary carotenoids provide indirect benefits as retinoid precursors, our observations suggest that carotenoids themselves may play little to no direct role in key physiological processes in birds.

Dietary carotenoids have been proposed to have physiological benefits in addition to contributing to coloration. Here, Koch et al. compare immune and antioxidant functions in yellow, carotenoid-rich vs. white, carotenoid-deficient canaries and find no difference, suggesting a limited physiological role of carotenoids.

Reversed-Phase High-Performance Liquid Chromatography for the Quantification and Optimization for Extracting 10 Kinds of Carotenoids in Pepper (Capsicum annuum L.) Leaves

Carotenoids are considered to be crucial elements in many fields and, furthermore, the significant factor in pepper leaves under low light and chilling temperature. However, little literature focused on the method to determinate and extract the contents of carotenoid compositions in pepper leaves. Therefore, a time-saving and highly sensitive reversed-phase high-performance liquid chromatography method for separation and quantification of 10 carotenoids was developed, and an optimized technological process for carotenoid composition extraction in pepper leaves was established for the first time. Our final method concluded that six xanthophylls eluted after about 9-26 min. In contrast, four carotenes showed higher retention times after nearly 28-40 min, which significantly shortened time and improved efficiency. Meanwhile, we suggested that 8 mL of 20% KOH-methanol solution should be added to perform saponification at 60 °C for 30 min. The ratio of solid-liquid was 1:8, and the ultrasound-assisted extraction time was 40 min.