Betalains are water-soluble, nitrogen-containing pigments responsible for the yellow-orange to red-violet hues in most species of the plant order Caryophyllales, which includes beetroot, quinoa, and prickly pear. Beyond their visual role, these compounds attract attention for their antioxidant, anti-inflammatory, chemopreventive, and neuroprotective properties, fueling a search for new natural sources and better production methods. Two classes exist: yellow betaxanthins and violet betacyanins, both built around a shared core molecule called betalamic acid. The enzyme that creates this core is 4,5-DOPA-extradiol-dioxygenase, known as DODA, which cleaves the amino acid L-DOPA in a way that lets betalamic acid form spontaneously before condensing with amines or amino acids to make betaxanthins, or with cyclo-DOPA to make betacyanins.

Until recently, betalain biosynthesis was documented almost exclusively in Caryophyllales plants, with scattered reports in a handful of fungi such as Amanita, Hygrocybe, and Hygrophorus, in bacteria including Gluconacetobacter diazotrophicus and Escherichia coli, in the cyanobacterium Anabaena cylindrica, and, strikingly, in the tardigrade Hypsibius henanensis. Neolecta irregularis occupies a uniquely basal position within the Ascomycota, the phylum that contains most known fungi. As one of the very few surviving members of the subphylum Taphrinomycotina and the only genus in the Neolectomycetes, it retains morphological and genomic features considered ancestral, sitting in an intermediate zone between filamentous fungi and yeasts. Its rarity and the inability to cultivate it have long blocked functional studies of its physiology.

The research team, working with two specimens preserved at the Denver Botanic Gardens fungarium, first extracted pigments from the yellow tongue-shaped fruiting bodies and analyzed them by high-performance liquid chromatography coupled to mass spectrometry. They screened for a full panel of fungal betalains, including muscaflavin and numerous amino-acid-derived betaxanthins, but none were detected. Instead, the main pigment turned out to be riboflavin, vitamin B2, identified by its retention time and exact mass of m/z 377.1464, matching the standard at m/z 377.1456. Fluorescence imaging under blue excitation confirmed the assignment, revealing the characteristic yellow-green glow of riboflavin. This finding matters because riboflavin production is a hallmark of certain fungi and bacteria, where it protects spores from ultraviolet radiation and supports flavin cofactor synthesis and redox defense.

The pigment analysis created a puzzle. RNA sequencing, performed for the first time on this species, showed that the fungus actively expresses the gene encoding a DODA enzyme, along with a cytochrome P450, yet the pathway appears incomplete. The researchers found no expression of prephenate dehydrogenase or tyrosine aminotransferase, the enzymes needed to make L-tyrosine de novo, which is the precursor to L-DOPA. Without this substrate, the betalain machinery cannot run in vivo, explaining why the fungus stays yellow from riboflavin rather than from betalains. The transcriptomic data, deposited in the NCBI Gene Expression Omnibus under accession GSE300630, revealed 24 genes related to riboflavin metabolism, underscoring the pigment’s physiological importance in this lineage.

To test whether the encoded enzyme actually works, the team cloned the NiDODA gene, optimized its sequence for expression in E. coli, and purified the resulting protein using cobalt affinity chromatography. The enzyme emerged as a monomer of 33.4 kilodaltons, confirmed by gel filtration and mass spectrometry. Structural modeling with AlphaFold showed a compact fold resembling the only crystallized betalamic-acid-forming protein, YgiD from E. coli, with which NiDODA shares just 25.2 percent sequence identity. Three conserved histidine residues, His10, His48, and His230, coordinate a metal ion at the active site, mirroring the arrangement in the bacterial enzyme. Inductively coupled plasma mass spectrometry identified iron as the likely cofactor, and supplementing purification buffers with iron boosted activity up to 8.5-fold.

Kinetic characterization revealed remarkable properties. The enzyme operates optimally at pH 6.0, notably more acidic than the pH 8.0 to 8.5 optima reported for DODAs from Amanita muscaria, beetroot, and E. coli. Most strikingly, NiDODA binds L-DOPA with a Km of 0.8 millimolar, the highest affinity ever recorded for any DODA enzyme. For comparison, the Amanita enzyme has a Km of 4.2 millimolar, beetroot 6.9, quinoa 1.5, and the cyanobacterial version a staggering 53,000 millimolar. This makes NiDODA the most efficient L-DOPA converter among all known betalain-forming dioxygenases, capable of producing betalamic acid, muscaflavin, and dopaxanthin from the same substrate.

Phylogenetic analysis placed NiDODA within a distinct fungal branch separate from plant, bacterial, and animal sequences. Ascomycota sequences clustered together, while the tardigrade enzyme branched off before the radiation of plants, fungi, and microorganisms, acting as an outgroup. The team found that Ascomycota genomes contain numerous uncharacterized proteins with similarity to NiDODA, all retaining the conserved histidine triad, suggesting that more fungal betalain-producing enzymes await discovery. This pattern supports convergent evolution, where similar catalytic solutions arise independently in distant lineages, a phenomenon already documented within Caryophyllales plants, where DODA activity emerged at least three times through gene duplication and neofunctionalization.

The broader implication is that betalain biosynthesis may have far deeper roots than previously appreciated. Rather than being a plant-specific innovation, the capacity to cleave L-DOPA into betalamic acid appears scattered across the tree of life, from fungi and bacteria to cyanobacteria and animals. Whether these enzymes represent an ancestral metabolic capacity predating eukaryotic diversification, or the result of horizontal gene transfer and convergent evolution, remains unresolved. The biological role of betalain-producing enzymes in non-plant organisms is also unknown, and the possibility that they serve functions beyond pigment formation, particularly in species that never make betalains, adds another layer of mystery.

For Neolecta irregularis itself, the study provides the first transcriptomic analysis of a species that has resisted cultivation and remains scarce in nature. It confirms that the fungus carries the genetic framework for betalain synthesis but cannot execute the pathway because it lacks the ability to produce L-tyrosine de novo. The identification of NiDODA as the second fungal betalain-producing enzyme characterized to date, and the first monomeric one, expands the known phylogenetic scope of the pathway and opens the door to exploring whether other Ascomycota species harbor similar dormant capacities. As researchers continue to probe these ancient lineages, enzymes like NiDODA may reveal how metabolic innovations emerge, persist, or vanish across evolutionary time, offering a rare glimpse into the biochemical toolkit of early fungal life.

Subject of Research: Betalain biosynthesis enzyme evolution in the early-diverging fungus Neolecta irregularis

Article Title: A functional betalain-producing dioxygenase in Neolecta irregularis reveals an expanded evolutionary origin of the pathway

Article References: Martínez-Rodríguez, P., Guerrero-Rubio, M. A., Henarejos-Escudero, P., Hernández-García, S., & Gandía-Herrero, F. (2026). A functional betalain-producing dioxygenase in Neolecta irregularis reveals an expanded evolutionary origin of the pathway. IMA Fungus, 17, Article e184549. https://doi.org/10.3897/imafungus.17.184549

Image Credits: AI Generated

DOI: 10.3897/imafungus.17.184549

Keywords: betalains, Neolecta irregularis, DODA enzyme, Ascomycota, riboflavin, L-DOPA dioxygenase, betalamic acid, convergent evolution, Taphrinomycotina, fungal pigments, heterologous expression, enzyme kinetics

The core of the review is a detailed accounting of what cactus actually contains. Far from being an empty succulent, the plant’s pads, known as cladodes, and its brightly colored fruits are packed with nutrients that rival or exceed those of more conventional produce. The analysis documents substantial levels of vitamins, including vitamin C, alongside meaningful quantities of minerals such as calcium, magnesium, and potassium. Dietary fiber emerges as one of the plant’s standout features, with both soluble and insoluble fractions present in the pads and fruit in significant amounts. This fiber content is not merely a bulk property; it underpins many of the physiological effects attributed to cactus consumption, from improved digestive function to better regulation of blood glucose and blood lipids. For populations where refined staples dominate the diet, such fiber-dense foods could play a meaningful corrective role.

Beyond the standard nutritional profile, the review devotes considerable attention to the plant’s bioactive compounds, the specialized molecules that give cactus its pharmacological reputation. Chief among these are betalains, the nitrogen-containing pigments responsible for the vivid magenta and orange hues of prickly pear fruit. Betalains are relatively rare in the edible plant kingdom, found prominently in cacti and beetroot, and they function as potent antioxidants capable of neutralizing reactive oxygen species that damage cells and drive chronic disease. The review also catalogs an array of polyphenols, including phenolic acids and flavonoids, which contribute additional antioxidant capacity and appear to modulate inflammatory signaling pathways. Carotenoids, another class of lipid-soluble pigments, add to the protective chemical arsenal. Together, these compounds form a complex phytochemical profile that the authors argue justifies classifying cactus as a functional food, meaning a food that delivers demonstrable health benefits beyond basic nutrition.

The health implications documented in the review are broad and, in several areas, striking. The evidence assembled points to significant antioxidant activity, which helps protect tissues from oxidative stress implicated in aging, cancer, and cardiovascular disease. Anti-inflammatory effects are similarly well supported, with cactus compounds shown to dampen the chronic low-grade inflammation that underlies many modern metabolic disorders. Perhaps most compelling for public health purposes are the anti-diabetic and cardioprotective properties. Multiple studies reviewed indicate that cactus consumption can improve glycemic control, an effect attributed to both its fiber content, which slows sugar absorption in the gut, and its bioactive compounds, which appear to influence glucose metabolism more directly. Cardioprotective effects include improvements in blood lipid profiles and reductions in blood pressure markers, suggesting that regular consumption could reduce the burden of cardiovascular disease, the leading cause of death worldwide.

What makes these findings particularly timely is the context in which they arrive. Global food systems face a convergence of pressures: a growing population expected to approach ten billion by mid-century, rising rates of diet-related chronic disease, and a climate that is making traditional agriculture increasingly unreliable in many regions. The review frames cactus as a plant uniquely suited to this predicament. Opuntia species are famously adapted to arid and semi-arid environments, employing a specialized form of photosynthesis known as crassulacean acid metabolism, or CAM, in which the plant opens its pores at night to minimize water loss. This physiological adaptation means cactus can produce food with minimal irrigation, tolerating drought conditions that would devastate conventional crops. In regions such as the Sahel, Mexico, the Mediterranean basin, and parts of South Asia, where water scarcity is already acute and worsening, this trait transforms cactus from a curiosity into a strategic resource.

The sustainability argument extends beyond water efficiency. Cactus plants thrive on degraded soils where other crops fail, require few chemical inputs, and can serve multiple functions simultaneously: food for humans, fodder for livestock, and even a vegetative barrier against soil erosion and desertification. The review explicitly connects these attributes to the United Nations Sustainable Development Goals, highlighting three in particular. SDG 2, Zero Hunger, is addressed through cactus potential to provide nutritious food in marginal environments where food insecurity is most severe. SDG 3, Good Health and Well-being, is supported by the plant’s documented functional food properties. SDG 13, Climate Action, is served by the crop’s resilience to climate variability and its low environmental footprint. This framing positions cactus not simply as a regional food tradition but as a candidate for deliberate integration into global food security strategy.

The authors, who also include Muhammed Adem Abdullahi of Jimma University, Vu Thi Kim Oanh of the Vietnam National University of Agriculture, and Kinfu Mekbib of the Addis Ababa Water and Sewerage Authority, emphasize that cactus is already a meaningful food source in many cultures. Indigenous and rural communities across the Americas, North Africa, and the Middle East have consumed prickly pear pads and fruit for centuries, and the plant holds particular cultural and economic significance in Mexico, where Opuntia cultivation is extensive. Yet despite this long history and the accumulating scientific evidence, cactus remains marginal in mainstream food markets and agricultural policy outside its traditional range. The review suggests this gap reflects a combination of limited consumer awareness, underdeveloped supply chains, and insufficient investment in processing technologies that could transform cactus into appealing modern food products such as juices, jams, flours, and nutraceutical extracts.

Processing and product development represent a critical frontier. The review notes that the bioactive compounds in cactus are sensitive to heat and processing conditions, meaning that preservation methods must be carefully designed to retain nutritional value. Betalains in particular are vulnerable to degradation, and optimizing extraction and stabilization techniques is an active area of food science research. At the same time, the plant’s versatility offers commercial opportunities: cactus fruit can be eaten fresh or processed into beverages and preserves, while cladodes can be consumed as vegetables, dried into powders, or incorporated into baked goods and functional food formulations. Developing these value chains in producing countries could create rural income opportunities while improving local nutrition, a dual benefit that aligns with broader sustainable development objectives.

As with any review, the strength of the conclusions depends on the quality of the underlying evidence, and the authors acknowledge that much of the research on cactus health effects comes from laboratory and animal studies, with a smaller body of controlled human trials. Translating promising bioactivity into verified clinical benefits will require rigorous intervention studies, standardized plant material, and better characterization of dose-response relationships. There are also agronomic questions to resolve, including varietal selection, cultivation practices, and post-harvest handling, areas where the authors’ own expertise in post-harvest management is directly relevant. The review’s open-access publication is intended to make this evidence base accessible to researchers, policymakers, and entrepreneurs who could accelerate the plant’s development.

Nevertheless, the overall message is one of considerable optimism. A plant that grows without irrigation on degraded land, produces food rich in fiber, vitamins, minerals, and rare antioxidant pigments, and offers documented anti-diabetic and cardioprotective properties is a rare asset in the search for sustainable food systems. As climate change redraws the map of where food can be reliably produced, crops adapted to heat and drought will inevitably move from the margins to the center of agricultural planning. The prickly pear cactus, long valued by the communities who knew it best, now has a scientific dossier to match its reputation. Whether it becomes a global staple or remains a regional treasure will depend on investment, innovation, and willingness to look beyond familiar crops, but the evidence assembled in this review makes a strong case that ignoring it would be a missed opportunity for both human health and planetary sustainability.

Subject of Research: Nutritional composition, bioactive compounds, and health and sustainability implications of the cactus plant (Opuntia spp.)

Article Title: A comprehensive review of nutritional composition and bioactive compounds of cactus plant and their implications for human health and sustainable development

Article References: Alemu, T. T., Abdullahi, M. A., Oanh, V. T. K., & Mekbib, K. (2026). A comprehensive review of nutritional composition and bioactive compounds of cactus plant and their implications for human health and sustainable development. Discover Sustainability. https://doi.org/10.1007/s43621-026-04892-1

Image Credits: AI Generated

DOI: 10.1007/s43621-026-04892-1

Keywords: cactus, Opuntia, prickly pear, betalains, polyphenols, functional food, antioxidants, anti-diabetic, food security, sustainable agriculture, climate resilience, Sustainable Development Goals

The rationale behind the study rests on the well-documented bioactive profiles of its two plant ingredients. Beetroot, a root vegetable of the Chenopodiaceae family, ranks among the top ten antioxidant vegetables thanks to its rich stores of betalains, phenolic acids, saponins, catechins, and flavonoids. It is also unusually high in dietary nitrates, which the human body converts into nitric oxide, a molecule that improves blood flow and cardiovascular function, a property that has earned beetroot a place in athletes’ performance regimens. Orange juice, meanwhile, contributes more than 100 tentatively identified carotenoids across citrus fruits, alongside generous vitamin C, flavonoids, and limonoids with anti-inflammatory and immune-supporting properties. Combining the two in a fermented dairy matrix, the researchers reasoned, could yield a beverage whose bioactive content far exceeds that of plain yoghurt, while the dairy proteins themselves may act as natural carriers that enhance the bioavailability of plant polyphenols through hydrophobic and electrostatic binding.

The experimental design was straightforward but rigorous in its analytical detail. Fresh beetroot roots and sweet oranges at commercial maturity were purchased from a certified market in Dhaka and transported under refrigeration. The beetroot was peeled, cubed, and blanched in boiling water for two minutes to inactivate the enzymes peroxidase and polyphenol oxidase, a step that stabilizes color and carotenoids, before being homogenized into a smooth pulp. Orange juice was extracted mechanically, filtered through muslin cloth, and stored in amber bottles at 4°C to prevent light-induced degradation of vitamin C and carotenoids. Full-fat cow’s milk was heat-treated at 85°C to 95°C for five minutes to denature whey proteins and improve water-holding capacity, then cooled and inoculated with a commercial starter culture of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, fermented to pH 4.5, and blended with the plant ingredients.

Three formulations were prepared, each containing a constant 30 milliliters of orange juice but varying amounts of beetroot pulp. Sample A combined 240 grams of yoghurt with 30 grams of beetroot pulp, Sample B paired 225 grams of yoghurt with a hefty 45 grams of pulp, and Sample C mixed 255 grams of yoghurt with just 15 grams. After homogenization, the drinks were bottled in sterilized 250-milliliter glass containers and refrigerated. This gradient approach allowed the team to probe how increasing beetroot concentration would shift the balance between nutritional enhancement, antioxidant capacity, and the sensory qualities that ultimately determine whether consumers will actually buy such a product.

The proximate analysis revealed meaningful differences tied directly to formulation. Moisture ranged from 81.72 percent in Sample C to 84.27 percent in Sample B, while Sample C, with its higher proportion of yoghurt, delivered the most nutrient-dense profile: 3.75 percent protein, 3.67 percent fat, and 10.33 percent carbohydrate. Sample B, diluted by its large beetroot fraction, had the lowest protein at 3.07 percent and fat at 3.15 percent. The pattern makes intuitive sense, since yoghurt contributes milk solids, proteins, and minerals, whereas beetroot pulp adds water, fiber, and plant solids that shift the moisture-to-total-solids ratio. These water-binding interactions among milk proteins, plant fibers, and polysaccharides matter greatly in fermented dairy, influencing both consistency and stability over time.

The bioactive results told an equally clear story. Sample B, with the most beetroot, achieved the highest DPPH radical-scavenging activity at 56.1 percent inhibition, the strongest total phenolic content at 51.4 milligrams of gallic acid equivalents per 100 grams, and the highest flavonoid content at 14 milligrams of catechin equivalents per 100 grams. Its IC50 value of 429.4 parts per million was the lowest, meaning less extract was needed to neutralize half of the free radicals in the assay. Sample C, with the least beetroot, lagged behind on every bioactive measure, failing to reach 50 percent inhibition even at the highest concentration tested. Beta-carotene-equivalent carotenoid content varied only narrowly, from 4.5 to 4.9 milligrams per 100 grams, across all three drinks. The researchers validated their spectrophotometric carotenoid method carefully, achieving 96.4 percent recovery, a calibration linearity above 0.99, and intra-day and inter-day precision below 5 percent relative standard deviation, though they caution that betalains and citrus pigments may overlap spectrally and recommend chromatographic confirmation in future work.

Sensory evaluation, conducted with a 30-member consumer panel using a nine-point hedonic scale, revealed the study’s central tension: more beetroot means more antioxidants, but also less palatability. Sample A, the moderate formulation, won decisively, scoring 7.63 for appearance, 8.00 for aroma, 8.07 for taste, and 7.90 for texture, all statistically superior to the other two formulations at p < 0.001. Sample C scored lowest on every attribute, a somewhat puzzling result given its lowest beetroot content, though the authors note that overall formulation balance and interactions among ingredients, rather than beetroot intensity alone, likely shaped the panel’s verdicts. The citrus component may play a helpful role here, since the natural sugars, acids, and volatile aromatics of orange juice can mask the earthy geosmin-derived notes that make beetroot polarizing at high concentrations.

On the safety and stability front, the news was reassuring. The pH of all three formulations declined gradually over 35 days of refrigerated storage, from around 4.5 initially to as low as 4.0 in Sample C by day 35, a normal post-acidification pattern driven by the residual metabolic activity of lactic acid bacteria. More importantly, coliform bacteria and Escherichia coli were never detected in any sample at any time point, with counts remaining below the detection limit of one colony-forming unit per milliliter throughout the entire storage period. That performance comfortably meets regulatory limits set by agencies such as the FDA and EFSA, which cap coliforms and E. coli in refrigerated foods at fewer than 10 colony-forming units per gram, and it points to good hygienic processing, proper fermentation control, and effective cold-chain preservation.

The authors are candid about the limitations that temper these findings. The study relied on a single production run, lacked an unfortified control, and measured only selected microbial indicators, leaving total viable counts and starter-culture dynamics uncharacterized. Nutritional analysis stopped at macronutrients, without profiling vitamins, minerals, or specific phytochemicals. Because technical replicates rather than independent batches formed the basis of the physicochemical data, the results should be read as preliminary formulation-level observations rather than definitive product claims. Still, the practical takeaway is clear and actionable: a moderate beetroot-and-orange fortification, as in Sample A, best preserves the taste and texture consumers expect, while a heavier beetroot load, as in Sample B, maximizes antioxidant and phenolic content. Future work with replicated production trials, chromatographic carotenoid profiling, and larger consumer panels will determine whether these vibrant pink-and-orange functional drinks can graduate from the laboratory bench to the supermarket chiller, but the evidence so far suggests that the humble drinking yoghurt has considerable untapped potential as a delivery vehicle for plant-derived bioactive compounds.

Subject of Research: Functional drinking yoghurt fortified with beetroot pulp and orange juice

Article Title: Physicochemical, Bioactive, Sensory, and Microbial Evaluation of Functional Drinking Yoghurt Fortified With Beetroot and Orange Juice

Article References: Khan, M. M. I., Ali, M. N., Tabassum, A., Bhattacharjee, D., Alam, S., & Islam, M. S. (2026). Physicochemical, Bioactive, Sensory, and Microbial Evaluation of Functional Drinking Yoghurt Fortified With Beetroot and Orange Juice. Food Science &amp; Nutrition, 14(10), Article e72452. https://doi.org/10.1002/fsn3.72452

Image Credits: AI Generated

DOI: 10.1002/fsn3.72452

Keywords: drinking yoghurt, beetroot, orange juice, functional foods, antioxidants, betalains, carotenoids, DPPH, total phenolic content, probiotics, food safety, sensory evaluation