An efficient process for the extraction of lutein and chemical characterization of other organic volatiles from marigold (Tagetes erecta L.) flower

De Novo Biosynthesis of Lutein in Yarrowia lipolytica

Lutein is a high-value tetraterpenoid carotenoid that is widely used in feed, cosmetics, food, and drugs. Microbial synthesis of lutein is an important method for green and sustainable production, serving as an alternative to plant extraction methods. However, an inadequate precursor supply and low catalytic efficiency of key pathway enzymes are the main reasons for the low efficacy of microbial synthesis of lutein. In this study, some strategies, such as enhancing the MVA pathway and localizing α-carotene synthase OluLCY within the subcellular organelles in Yarrowia lipolytica, were adopted to enhance the synthesis of precursor α-carotene, which resulted in a 10.50-fold increase in α-carotene titer, reaching 38.50 mg/L. Subsequently, by improving hydroxylase activity with truncated N-terminal transport peptide and locating hydroxylases to subcellular organelles, the final strain L9 producing 75.25 mg/L lutein was obtained. Eventually, a lutein titer of 675.40 mg/L (6.13 mg/g DCW) was achieved in a 5 L bioreactor by adding the antioxidant 2,6-ditert-butyl-4-methylphenol. This study realizes de novo synthesis of lutein in Y. lipolytica for the first time and achieves the highest lutein titer reported so far.

Sustainable Green Extraction of Carotenoid Pigments: Innovative Technologies and Bio-Based Solvents

Carotenoids are ubiquitous and versatile isoprenoid compounds. The intake of foods rich in these pigments is often associated with health benefits, attributable to the provitamin A activity of some of them and different mechanisms. The importance of carotenoids and their derivatives for the production of foods and health-promotion through the diet is beyond doubt. In the new circular economy paradigm, the recovery of carotenoids in the biorefinery process is highly desirable, for which greener processes and solvents are being advocated for, considering the many studies being conducted at the laboratory scale. This review summarizes information on different extraction technologies (ultrasound, microwaves, pulsed electric fields, pressurized liquid extraction, sub- and supercritical fluid extraction, and enzyme-assisted extraction) and green solvents (ethyl lactate, 2-methyltetrahydrofuran, natural deep eutectic solvents, and ionic liquids), which are potential substitutes for more toxic and less environmentally friendly solvents. Additionally, it discusses the results of the latest studies on the sustainable green extraction of carotenoids. The conclusions drawn from the review indicate that while laboratory results are often promising, the scalability to real industrial scenarios poses a significant challenge. Furthermore, incorporating life cycle assessment analyses is crucial for a comprehensive evaluation of the sustainability of innovative extraction processes compared to industry-standard methods.

Lutein-Rich Beverage Alleviates Visual Fatigue in the Hyperglycemia Model of Sprague-Dawley Rats

Asthenopia is a syndrome based on the symptoms of eye discomfort that has become a chronic disease that interferes with and harms people's physical and mental health. Lutein is an internationally recognized "eye nutrient", and studies have shown that it can protect the retina and relieve visual fatigue. In this study, lutein was extracted from marigold (Tagetes erecta L.) and saponified. The purified lutein concentration measured by HPLC was 50.12 mg/100 g. Then, purified lutein was modified to be water-soluble by nanoscale modification and microencapsulation technology. Water-soluble lutein was then mixed with a leaching solution of Chinese wolfberry and chrysanthemum to make a functional beverage. The effects of this beverage on hepatic antioxidant enzymes and the alleviation of visual fatigue in a rat model of diabetes were investigated for 4 weeks. Lutein intake of 0.72 (medium-lutein beverage group) and 1.44 mg/mL (high-lutein beverage group) relieved visual fatigue, ameliorated turbidity symptoms of impaired crystalline lenses, reduced hepatic MDA concentration, increased hepatic GSH concentration, and significantly increased the activities of the hepatic antioxidant enzymes SOD, CAT, GSH-Px, and GR in rats. These data suggest that a lutein-rich beverage is an effective and harmless way to increase the total anti-oxidation capacity of lenses and alleviate visual fatigue.

Chemical Composition, Antioxidant and Antibacterial Activities of Essential Oil Obtained from Chincho (Tagetes elliptica Sm) Leaves Grown in the Peruvian Andes

The chemical composition, antioxidant, and antibacterial properties of the essential oil from the leaves of Tagetes elliptica Sm., grown in Peru, were studied. The EO was extracted using steam distillation, and its chemical composition was analyzed using GC-MS, while the antioxidant activity was evaluated using the radical, scavenging capacity (DPPH and ABTS assays), and ferric reducing antioxidant power (FRAP) assays, ferrous ion chelating (FIC) activity, and the Rancimat test. The antibacterial activity against Staphylococcus aureus, Escherichia coli, and Salmonella infantis was studied using the agar well diffusion method. Twenty-seven compounds were identified in the essential oil, and the major components were cis-tagetenone (37.27%), trans-tagetenone (18.84%), dihydrotagetone (14.38%), and trans-tagetone (5.15%). With regard to antioxidant properties, the IC₅₀ values obtained for the DPPH, ABTS, and FIC assays were 53.37, 46.38, and 22.65 mg/mL, respectively. These values were lower than those obtained for standard butylated hydroxytoluene and ascorbic acid. In the Rancimat test, antioxidant activity was achieved only at high concentration. T. elliptica essential oil showed a marked antibacterial activity against all bacterial strains at all concentrations assayed. This study demonstrated that T. elliptica essential oil could be considered as an alternative to synthetic antioxidants and antimicrobial agents in the food industry.

Development of Chincho (Tagetes elliptica Sm.) Essential Oil Organogel Nanoparticles through Ionic Gelation and Process Optimization with Box-Behnken Design

The aim of this work was to obtain chitosan nanoparticles (<1000 nm) with chincho (Tagetes elliptica Sp.) essential oil (CEO-CSNPs) using the ionic gelation method. A Box−Behnken design (BBD) was applied, using chitosan solution (CS) pH (4.0, 4.4, 4.8); the mass ratio of CS/CEO (1:0.7, 1:0.85, 1:1.0) and the mass ratio of CS/CS-tripolyphosphate (1:0.46, 1:0.58, 1:0.7) as independent variables. The formulation-dependent variables, encapsulation efficiency (EE) and loading capacity (LC) of the CEO-CSNPs were evaluated. BBD determined that optimal conditions for CEO-CSNPs were pH: 4.4, CS/CEO mass ratio 1:0.7 and CS/TPP mass ratio 1:0.46. Once the optimization was defined, particle size (PS), zeta potential (ZP), polydispersity index (PDI), CEO-CSNPs morphological studies, in vitro CEO release, and antibacterial activity were determined. The CEO-CSNPs showed an EE of 52.64% and a LC of 11.56%, with a diameter of 458.5 nm, with a ZP of 23.30mV, and a PDI of 0.418. The SEM studies showed that the nanoparticles were rounded and had uniform shapes. In addition, CEO-CSNPs showed a minimum inhibitory concentration against Staphylococcus aureus, Salmonella infantis and Escherichia coli of 5.29, 10.57 and 10.57 µg/mL, respectively. These results could be very useful for the stabilization of chincho essential oil for food industry purposes. However, several studies about the release, as well as interaction with food matrices, will be necessary.