The research responds to growing pressure on the confectionery industry to move away from synthetic colorants. Regulatory trends in both the European Union and the United States increasingly restrict synthetic food dyes in favor of plant- and marine-derived alternatives, and in the EU, natural coloring ingredients can often be classified as "coloring foodstuffs" rather than additives, sidestepping stringent E-number regulations and aligning with clean-label consumer demands. Ulva lactuca, common green seaweed known for rapid growth and ease of cultivation, is rich in phenolic compounds, chlorophylls, carotenoids, and sulfated polysaccharides such as ulvan, making it a candidate for multifunctional, rather than purely cosmetic, ingredient roles. The choice of two dissimilar confectionery matrices was deliberate: fondant represents a low-moisture, crystalline sugar system in which added ingredients interact primarily with sucrose crystals and the saturated syrup surrounding them, while meringue is a whipped egg white foam whose structure depends on intact protein films stretched around air cells. Any single functional ingredient can behave very differently in these two environments, so testing both provides a broader picture of how an algal extract might perform across the wider confectionery landscape, from gummies and icings to foamed desserts and nougats.

The researchers harvested fresh U. lactuca thalli from Cakalburnu Lagoon in southern Izmir Bay during a seasonal bloom in January 2024. After rinsing to remove sand and epibionts, the biomass was freeze-dried to protect heat-sensitive pigments, pulverized, and stored at minus 18 degrees Celsius. Bioactives were recovered using ultrasound-assisted extraction in absolute ethanol at 40 degrees Celsius for 30 minutes, with calcium carbonate and the antioxidant pyrogallol added to guard against pigment degradation. The resulting extract contained 0.849 milligrams of chlorophyll a and 1.756 milligrams of chlorophyll b per gram of dry biomass, plus 0.235 milligrams of total carotenoids per gram. Ultrasound-assisted extraction works by propagating acoustic cavitation — the rapid formation and collapse of microscopic bubbles — through the solvent, which ruptures cell walls and accelerates the release of intracellular compounds without the prolonged heating that would otherwise degrade chlorophylls. Calcium carbonate buffers acidity that can convert the bright green chlorophylls into olive-brown pheophytins, while pyrogallol scavenges oxygen species that would otherwise bleach carotenoids during processing. Together these choices reflect the central technical challenge of working with marine pigments: the same molecules that provide vivid natural color are chemically fragile.

The extract was then blended into fondant at 0.31, 0.63, and 1.25 percent by weight — added late in processing, once the sugar mass had cooled to roughly 40 degrees Celsius to minimize thermal damage — and into meringue foam at 0.08, 0.16, 0.31, and 0.63 percent before baking at 105 degrees Celsius for 90 minutes. This design allowed a direct comparison of processing impacts: post-thermal addition in fondant versus pre-baking exposure in meringue. In practice, the fondant protocol mirrors what a commercial confectionery line could do with minimal process change, since coloring pastes are routinely folded in at the cooling stage, whereas the meringue protocol exposes the bioactives to nearly an hour and a half of moderate oven heat — a much harsher test of pigment and antioxidant survival.

Color analysis using CIE Lab* measurements showed strong, concentration-dependent pigmentation. Untreated fondant was off-white with a lightness value near 89; even the lowest extract dose dropped lightness to about 60, deepened green tones, and produced a total color difference far above the threshold of human perception. Meringues followed a similar pattern, with lightness falling from 94.4 in controls to 66.2 at the highest dose. In the Lab* system, L* measures lightness, a* spans red to green, and b* spans blue to yellow; total color difference, or delta-E, aggregates shifts across all three axes, with values above roughly two to three typically visible to the average observer. After one month of storage, the lowest fondant dose showed the best color stability, with chromatic shifts below the roughly 5 percent level generally considered imperceptible to consumers, while higher doses exhibited greenness and yellowness losses exceeding 20 percent. In meringues, the green parameter was notably stable even at higher doses, which the authors attribute to a hypothesized protective role of the egg white protein network surrounding chlorophyll pigments — a safeguard absent in the sucrose-rich fondant. The implication for product developers is that the matrix itself can act as a pigment stabilizer, and that pairing seaweed extracts with protein-rich foods may extend shelf-life color performance without added stabilizers.

Functional enrichment was evident in both matrices. Total phenolic content in fondant rose from 0.80 to 9.96 milligrams of gallic acid equivalents per 100 grams of dry sample, while meringue phenolics climbed roughly sevenfold, from 19.13 to 150.95 milligrams GAE per 100 grams. Antioxidant activity measured by ABTS assay in fondant increased about 2.4-fold at the highest dose, and DPPH scavenging in meringue surged more than sixfold, from 8.37 to 53.28 micromolar Trolox equivalents per gram of dry matter. The two assays work by slightly different mechanisms — ABTS measures the ability of antioxidants to quench a pre-formed radical cation, while DPPH tracks reduction of a stable nitrogen radical — so observing gains in both strengthens the conclusion that the extract genuinely confers radical-scavenging capacity rather than merely interfering with a single test chemistry. The authors suggest that pre-baking incorporation in meringue may have enhanced the release or extractability of bound phenolics during thermal processing, and that egg white proteins may stabilize phenolics through non-covalent bonding — though they note the mechanisms behind the fondant-meringue discrepancy remain theoretical. If confirmed, protein–polyphenol associations, often viewed purely as a problem in beverage haze, could be reframed as a deliberate tool for carrying fragile bioactives through thermal processing.

The trade-offs appeared most clearly in structure and texture. Meringue baking yield fell steadily from 77.25 percent in controls to 69.66 percent at 0.63 percent extract, and the volume index collapsed from 319 to 88, consistent with phenolic interference in the egg white protein network that stabilizes the foam. Phenolic compounds are well known to bind proteins non-covalently, and in whipped foams such binding can hinder the unfolding and cross-linking of ovalbumin and other egg white proteins at the air–water interface, weakening the films that hold gas cells together during baking. Hardness in meringues dropped from 1,776 grams in controls to 963 grams at the highest dose, shifting the texture from dry and brittle to soft and plastically deformable. Fondant showed subtler changes: hardness peaked slightly at the lowest dose before declining, while springiness, cohesiveness, and chewiness all fell in a dose-dependent manner, likely because the extract's bioactives disrupt sucrose crystallization and hydrogen bonding within the sugar network. Because fondant's characteristic smooth, pliable body depends on a fine, controlled population of sucrose microcrystals, any ingredient that interferes with crystal nucleation or growth can soften the matrix and alter its shortness. Water activity dropped in both products — from 0.81 to 0.70 in fondant and 0.45 to 0.30 in meringue — as the extract's hydroxyl-rich compounds bound free water. Lower water activity generally improves microbiological stability and extends shelf-life in low-moisture foods, so this side effect could prove commercially useful, provided the accompanying texture shifts remain within consumer tolerance.

Sensory panels of 15 semi-trained assessors confirmed the dose-response trade-off. In fondant, the 0.31 percent sample maintained overall acceptability above 7.0 on a nine-point hedonic scale, while the 1.25 percent version scored 5.39. Meringues remained resilient up to 0.16 percent extract but deteriorated sharply beyond that. Panelists cited the intense green pigmentation and marine, earthy odors as the main detriments at elevated doses, alongside texture losses tied to disrupted crystallization and foam collapse. The hedonic scale, which ranges from "dislike extremely" at one to "like extremely" at nine, is a standard industry benchmark, and a fall from above 7.0 to 5.39 represents the difference between a product consumers would readily rebuy and one they would likely reject. Notably, the optimal doses identified analytically — 0.31 percent in fondant and 0.16 percent in meringue — coincided with the sensory tipping points, suggesting that laboratory measurements of color, antioxidant capacity, and texture track consumer perception closely in these systems.

Complementary structural analyses supported the biochemical picture. Fourier-transform infrared spectroscopy identified hydroxyl groups, carboxylate stretches, and sulfate ester signals characteristic of ulvan, providing a molecular basis for the water-binding and antioxidant behaviors observed. Scanning electron microscopy revealed an irregular, wrinkled, microporous morphology in the raw seaweed, features that support high extraction efficiency and bioactive release. Ulvan, the signature sulfated polysaccharide of Ulva species, carries abundant sulfate and carboxyl groups along its backbone, giving it strong affinity for water molecules and a capacity to interact with proteins and minerals — properties increasingly exploited in the food industry for films, stabilizers, and encapsulation carriers.

The authors acknowledge important limitations. The study focused on freshly prepared products, with color stability monitored for only one month; algal chlorophylls and other bioactives remain vulnerable to light- and oxygen-driven degradation over longer horizons. Quantification of iodine and heavy metals — key safety parameters for regulatory compliance under EFSA guidelines — was explicitly beyond the scope of this work and will be essential before commercial application. Seaweeds are efficient bioaccumulators of iodine, cadmium, and arsenic species, and EU food safety assessments of algal ingredients consistently hinge on these measurements, making their absence from the dataset a meaningful gap rather than a formality. The team also flags the need for industrial-scale ultrasound extraction systems, long-term shelf-life and microbiological studies, microencapsulation to stabilize pigments, and flavor-masking strategies using compatible natural additives such as vanilla or citrus extracts to offset marine notes without compromising clean-label status.

Extensively focusing on the Israeli Mediterranean coast, the research elucidates how the interplay of warm temperatures, intense and prolonged sunlight, and dynamic coastal oceanography create an environment conducive to the growth of red, brown, and green seaweeds harboring potent bioactive molecules. The study, spearheaded by Dr. Doron Yehoshua Ashkenazi and supervised by Professors Avigdor Abelson and Álvaro Israel, represents an integrative ecological-biotechnological approach that bridges marine biology, chemistry, and biotechnology. Through nearly four years of systematic specimen collection and analysis, the team identified 55 distinct seaweed species, with an unprecedented depth of chemical profiling that significantly advances our understanding of Mediterranean macroalgal biodiversity.

One of the study’s groundbreaking revelations pertains to a shift in seasonal growth patterns of seaweeds in the eastern Mediterranean basin. Contrary to earlier paradigms positing bimodal productivity peaks, this research demonstrates a singular, prominent growth season concentrated in the spring months. This alteration likely reflects the broader manifestations of climate change, notably global warming, reshaping marine ecosystems and prompting a reevaluation of biomass cycles critical for ecological forecasting and resource management. The emergent seasonality bears implications not only for biodiversity conservation but also for optimizing seaweed harvesting schedules aimed at maximizing biochemical yields.

Delving into the biochemical domain, the investigation reveals notably elevated protein concentrations in seaweed species during the winter season. Comprising a substantial fraction of their dry weight, these proteins position Israeli seaweeds as promising alternative proteins, potentially alleviating pressure on terrestrial agriculture and contributing to sustainable food security. Furthermore, antioxidant content peaks sharply in spring, with some species exhibiting increases up to 286%, underscoring their role as natural reservoirs of health-promoting compounds. These molecules are implicated in mitigating oxidative stress, hence offering therapeutic potential for immune enhancement and longevity.

Beyond proteins and antioxidants, the seaweeds analyzed exhibit high concentrations of phenolic substances and naturally derived ultraviolet (UV) filters. Such traits render them ideal candidates for eco-friendly cosmeceutical applications, positioning the Israeli Mediterranean seaweed biome at the nexus of marine bioprospecting and sustainable dermatological innovation. These compounds contribute photoprotective and anti-inflammatory properties that could revolutionize formulations in skincare, providing biogenic substitutes to synthetic chemicals with ecological footprints.

Central to the distinctive biochemical profile observed is Israel’s unique geographic and oceanographic positioning. As Dr. Ashkenazi elaborates, the subtropical climatic zone, characterized by year-round irradiance, coupled with rocky shorelines featuring minimal tidal variation and elevated seawater salinity, forms an ideal milieu for macroalgal metabolic specialization. These conditions stimulate natural ‘biological factories’ within seaweeds, producing bioactive molecules at concentrations surpassing those documented in other Mediterranean or global marine environments. This ecological niche thus transforms the Israeli Mediterranean into a living laboratory for marine biotechnological exploration.

From a technological and industrial perspective, the findings bear significant promise for advancing marine biotechnology in Israel. The integration of ecological insights with biotechnological methodologies, as emphasized by Prof. Álvaro Israel, enables the development of aquaculture techniques tailored to local species and conditions. Cultivation of these bioactive-rich seaweeds could catalyze sustainable production systems requiring no arable land, enhancing oxygen generation, carbon sequestration, and water purification. This paradigm aligns with global imperatives for environmentally responsible bioproduct manufacturing and circular economy principles.

The implications of this research extend to global environmental and economic challenges, with seaweed cultivation offering a dual solution: mitigating climate change impacts and generating economic opportunities. As Dr. Eitan Salomon underscores, the biotechnological exploitation of seaweeds encompasses a broad spectrum from functional foods to advanced therapeutics, potentially transforming health-related industries. The natural bioactive compounds extracted from these macroalgae could lead to novel drugs, nutraceuticals, and holistic health products, reinforcing the seaweed’s status as a ‘green treasure’ in ocean resources.

Furthermore, the Israeli Mediterranean seaweed ecosystem serves as an important model for assessing climate change responses in marine biota. Prof. Avigdor Abelson highlights the significance of using this natural laboratory to predict shifts in species distribution, productivity, and chemical profiles under warming scenarios. Understanding these dynamics is crucial to crafting adaptive management strategies that can safeguard marine biodiversity and ensure the sustainable exploitation of bioresources in a rapidly changing environment.

The comprehensive nature of this study also pays tribute to the legacy of Dr. Itzchak Brickner, a visionary marine biologist who greatly influenced Israeli marine sciences. His mentorship and pioneering efforts laid the groundwork for contemporary marine ecological research, inspiring this multifaceted exploration into marine biodiversity and biotechnology. The dedication reflects the ongoing commitment within the scientific community to honor foundational contributions while pushing the boundaries of knowledge.

In terms of methodology, the multidisciplinary research deployed a suite of advanced biochemical assays, including quantitative protein analysis, antioxidant capacity measurements, and phenolic compound quantification. Sampling was strategically performed along coastal transects capturing seasonal variability and species diversity. Such rigorous data collection and analytical protocols ensured that the findings rest on a robust empirical foundation, facilitating reproducibility and practical application of results within industrial and ecological contexts.

This landmark study not only situates Israel at the forefront of marine biotechnological innovation but also underscores the crucial role of marine ecosystems in global sustainability agendas. By revealing how natural environmental gradients influence bioactive compound synthesis in seaweeds, it opens new avenues for sustainable resource exploitation that marry ecological stewardship with technological advancement. The “green treasure” of the Israeli Mediterranean thus emerges as a beacon of hope for future food security, health innovation, and climate resilience in marine biotechnology.

Subject of Research: Marine macroalgae (seaweeds) ecology, biochemistry, and biotechnology in the Israeli Mediterranean Sea
Article Title: (Information not provided)
News Publication Date: (Information not provided)
Web References: http://dx.doi.org/10.3390/md23080320
References: Marine Drugs journal article DOI 10.3390/md23080320
Image Credits: Doron Yehoshua Ashkenazi
Keywords: Life sciences, Organismal biology, Marine biology