The original study, published on 23 September 2024 in volume 31 of the journal on pages 58176 through 58195, reported an environmentally friendly route to two nanomaterials: metallic copper nanoparticles and copper oxide nanoparticles, both synthesized using omega-3 compounds as the mediating agent. According to the paper’s framing, these so-called ω-3-Cu and ω-3-CuO nanocatalysts offered a dual application, serving both to decolorize synthetic dyes, a pressing problem in wastewater treatment, and to catalyze aerobic oxidation reactions, a cornerstone of green chemistry in which molecular oxygen replaces harsher oxidizing reagents. The work sat at the intersection of nanochemistry, biocatalysis, and environmental chemistry, fields that have attracted enormous attention as researchers search for sustainable alternatives to conventional industrial catalysts.

The specific trigger for the retraction was Figure 12 of the original article, which contained a spectrum whose noise region appeared to display a number of repetitive patterns. To a specialist, this detail matters enormously. In analytical spectroscopy, the noise floor of a genuine measurement is essentially random, a stochastic fingerprint of thermal fluctuations, detector electronics, and environmental interference. When the noise in a spectrum repeats itself in recognizable patterns, it can indicate that the spectrum has been digitally assembled, spliced, or copied from other sources, because genuine raw data almost never reproduce identical waveform segments across different regions of a single trace. Image forensics software and increasingly vigilant human eyes have made such duplications far easier to detect, and journals now routinely screen submitted figures for exactly these signatures.

Compounding the concern over the figure was the authors’ response to requests for verification. According to the retraction notice, the authors were unable to provide their raw data upon request. In modern research integrity practice, the inability or refusal to produce primary data is often decisive. Raw data, whether instrument output files, laboratory notebooks, or original digital images, allow editors to confirm that published figures faithfully represent actual measurements. When raw data cannot be produced, the journal has no way to distinguish an honest bookkeeping failure from fabrication, and the conservative response is to retract. The Editor-in-Chief concluded that confidence in both the data and the conclusions of the article could no longer be maintained, and the retraction followed.

The human dynamics of the retraction are also revealing. Author Idhayadhulla Akbar, the corresponding author affiliated with the Research Department of Chemistry at Nehru Memorial College in Tamil Nadu, India, disagrees with the retraction. The other named authors, Janani Mullaivendhan of Nehru Memorial College, Anis Ahamed of the Department of Botany and Microbiology at King Saud University in Riyadh, Saudi Arabia, and Raman Gurusamy of the Department of Life Science at Yeungnam University in South Korea, did not respond to correspondence from the publisher regarding the retraction. This pattern, in which one author contests the action while the remaining authors remain silent, is not uncommon in retraction cases and often reflects disagreement within a research team about how the underlying work was conducted and documented.

The scientific premise of the retracted paper was, in itself, part of a legitimate and active research frontier. Green synthesis of metal nanoparticles uses biological molecules, plant extracts, or other benign reagents to reduce metal salts and stabilize the resulting particles, avoiding the toxic solvents and reducing agents of classical colloidal chemistry. Copper and copper oxide nanoparticles are particularly attractive because copper is abundant and inexpensive compared with noble metals such as palladium, platinum, and gold, yet it can catalyze a wide range of transformations. In dye decolorization, copper-based nanomaterials can activate reducing agents or generate reactive species that break the chromophoric bonds responsible for a dye’s color, offering a potential treatment route for textile effluents that contaminate waterways in major manufacturing regions.

In aerobic oxidation, the appeal is equally strong. Oxidation reactions account for a substantial share of industrial chemical production, but many traditional processes rely on stoichiometric oxidants such as chromium or manganese reagents that generate hazardous waste. Catalysts that harness molecular oxygen from air as the terminal oxidant promise cleaner atom economies and milder conditions. Nanoscale copper catalysts, with their high surface-to-volume ratios and tunable surface chemistry, have been explored extensively for such applications, and pairing a biological stabilizing agent like omega-3 fatty acids with copper chemistry was a plausible and even elegant concept. The retraction does not invalidate the broader research field; it removes one specific set of reported results from the literature because their evidentiary basis could not be verified.

The case illustrates how the machinery of post-publication scrutiny now operates. Large publishers deploy automated image-integrity screening during peer review, and readers, many of them anonymous sleuths active on online forums, routinely flag suspicious figures long after publication. Once a concern is raised, the journal follows a process that typically includes notifying the authors, requesting original data and explanations, consulting institutional authorities where appropriate, and reaching a decision by the Editor-in-Chief. The timeline in this case, from publication in September 2024 to retraction in September 2026, reflects the often slow and legally cautious nature of such investigations, which must balance the urgency of protecting the literature against the due-process rights of the authors involved.

For the research community, the practical consequences of a retraction are concrete. The article remains online but is watermarked as retracted and linked to the retraction notice, so that readers who encounter it through databases or search engines are warned. Citation databases such as Scopus and Web of Science mark the record, and responsible authors are expected to exclude retracted papers from their literature syntheses and meta-analyses. In fields like nanocatalysis, where reported catalytic activities can influence the design of follow-up experiments, the removal of an unreliable dataset prevents other groups from wasting time and resources attempting to reproduce results that may never have been real.

The broader lesson is one that the scientific publishing ecosystem has been learning repeatedly in recent years: spectacular claims of eco-friendly, dual-purpose nanocatalysts attract attention, funding, and citations, which in turn create incentives that can tempt researchers toward shortcuts. The detection tools, however, have grown sharper. Repetitive patterns in spectral noise, once nearly invisible in print, are now flagged by algorithms and human experts alike, and the failure to produce raw data has become a decisive test that fabricated work cannot pass. The retraction of the omega-3 mediated copper nanocatalyst paper is a reminder that in green chemistry, as in every other discipline, sustainability claims must themselves rest on sustainable standards of evidence, and that the scientific record, however slowly, does correct itself.

Subject of Research: Retraction of a published study on omega-3 mediated copper and copper oxide nanocatalysts for dye decolorization and aerobic oxidation

Article Title: Retraction Note: Synthesis of omega-3 mediated copper (ω-3-Cu) and copper oxide (ω-3-CuO) nanocatalyst dual application of dye decolourization and aerobic oxidation of eco-friendly sustainable approach

Article References: Mullaivendhan, J., Ahamed, A., Gurusamy, R., & Akbar, I. (2026). Retraction Note: Synthesis of omega-3 mediated copper (ω-3-Cu) and copper oxide (ω-3-CuO) nanocatalyst dual application of dye decolourization and aerobic oxidation of eco-friendly sustainable approach. Environmental Science and Pollution Research. https://doi.org/10.1007/s11356-026-38270-1

Image Credits: AI Generated

DOI: 10.1007/s11356-026-38270-1

Keywords: retraction, nanocatalyst, copper nanoparticles, copper oxide, green chemistry, omega-3, dye decolorization, aerobic oxidation, research integrity, spectral data, Environmental Science and Pollution Research, raw data

The research team, led by scientists from Mengniu Dairy’s Ambient Product Research and Development Centres, purchased sixteen commercial UHT whole milk products from the Chinese e-commerce platform Jingdong Mall. Six samples were produced in China, five in Western Europe, drawn from the Netherlands, Germany, Austria, Ireland, and Spain, and five from Australia and New Zealand. Imported products explicitly labeled as grass-fed or pasture were preferentially selected to maximize the likelihood that they represented grazing-based production systems, although the authors caution that label claims do not guarantee the annual diet of any herd. All samples contained only raw milk or organic raw milk with no additives, and all were packed in aseptic cartons.

The analytical arsenal deployed on these sixteen cartons was formidable. Gross composition, including fat, protein, lactose, solid-non-fat, and total solids, was measured by mid-infrared spectroscopy. Fatty acids were quantified by gas chromatography with flame ionization detection according to the Chinese national standard GB 5009.168. Fat-soluble vitamins A and E were determined by high-performance liquid chromatography with diode-array detection, while riboflavin was measured by HPLC with UV/visible detection. Niacin, pantothenic acid, and folic acid were assessed with commercial assay kits, choline by ion chromatography, and a panel of minerals, including calcium, potassium, sodium, magnesium, zinc, selenium, and iodine, by inductively coupled plasma mass spectrometry. Phosphorus was determined spectrophotometrically. This breadth matters because single-nutrient comparisons can be misleading; milk quality is a multivariate property.

The macronutrient results revealed a subtle but telling pattern. Measured fat and lactose levels of the domestic samples were significantly higher than those of the imported milks, and the domestic products showed the highest fat, vitamin E, vitamin B3, zinc, and iodine content, while milk from Australia and New Zealand had the lowest levels of fat, solids, and vitamin A. Interestingly, the measured fat and protein values for domestic milk exceeded typical raw-milk averages reported for China, pointing to standardization practices in dairy processing, particularly for domestic products claiming 3.6 grams of protein per 100 milliliters. Minerals tied to casein micelles, such as calcium, phosphorus, and magnesium, showed no significant regional differences, likely because protein standardization counteracts the feed-driven variation that previous studies have documented for grazing versus total mixed ration systems.

The vitamin findings may be the study’s most counterintuitive result. Fresh and ensiled grass is an excellent source of fat-soluble vitamins, so one might expect pasture-fed European and Oceanian milk to contain more vitamin A and vitamin E. The opposite was observed. The researchers attribute this to the harsher thermal reality of imported UHT milk: longer transportation distances demand longer shelf lives and higher heat loads, and quality reports cited in the paper show imported UHT milk carried markedly higher heat-load indicators such as furosine and lactulose between 2021 and 2023. Vitamin A degrades through isomerization of its unsaturated isoprenoid side chain during thermal processing, and vitamin E loss increases with temperature and holding time. Degradation continues even under refrigeration, with losses of roughly 8 percent for vitamin A and 11 percent for vitamin E after thirty days of storage. In contrast, water-soluble vitamin B2 was higher in imported milk, consistent with its origin in green leafy forage, while vitamin B3, derived mainly from cereal grains, was higher in domestic milk, matching expectations for grain-heavy total mixed rations.

The fatty acid analysis produced perhaps the clearest separation between regions. Total saturated and monounsaturated fatty acids did not differ significantly, but the polyunsaturated fatty acid picture split sharply along the n-3 and n-6 families. Domestic Chinese milk was richer in n-6 fatty acids, including C18:2n-6c, C18:3n-6, C20:3n-6, and C20:4n-6, whereas imported milks carried higher levels of n-3 fatty acids such as C18:3n-3, C20:3n-3, and C20:5n-3. The imported samples achieved an n-3/n-6 ratio of approximately 0.31 to 0.32, compared with only 0.12 for Chinese milk. The biochemistry behind this split is well understood: pasture is rich in alpha-linolenic acid, an omega-3 precursor, while maize silage, cereals, and oilseeds in mixed rations supply abundant linoleic acid, an omega-6. These dietary fatty acids are then elongated and desaturated in the mammary gland, amplifying the regional differences in long-chain polyunsaturates.

Shorter-chain fatty acids told the same story from a different angle. Imported milk contained significantly higher levels of C4, C6, C12, and C14, reflecting the fact that high-fiber pasture diets stimulate de novo fatty acid synthesis in the udder, whereas the high-starch rations of confined systems lower ruminal pH and suppress this synthesis. Odd-chain fatty acids, C11, C15, C17, and C21, were also significantly elevated in imported milk, and these compounds are recognized biomarkers of pasture-based feeding because they arise from rumen microbial fermentation of forage. The paper notes that omega-3 fatty acids are associated with reduced risk of cardiovascular disease, diabetes, cancer, and mental disorders, and that the dietary n-3/n-6 ratio of Chinese consumers is suboptimal. However, the authors are careful to add a crucial caveat: milk products account for only about 2.3 percent of Chinese food intake and roughly 1 percent of daily milk fat consumption, so switching to imported milk alone cannot transform the overall dietary fatty acid profile. Pairing milk with omega-3-rich foods such as deep-sea fish, nuts, and flaxseeds remains essential.

Sensory evaluation added a human dimension to the chemistry. Eight trained, certified assessors evaluated the samples in duplicate on a nine-point hedonic scale after a structured three-day training program. Imported milks scored significantly higher for cowy and tea flavors and for astringency, while domestic samples appeared brighter in color and sweeter. The yellow-cream hue of grass-based milk reflects high carotenoid and riboflavin levels in forage, whereas total-mixed-ration milk tends toward white. The cowy note is linked to compounds such as p-cresol, a consistent marker of pasture diets, and the higher sweetness scores for domestic milk align with its higher measured lactose content. Notably, despite the heavier heat treatment of imported products, no significant difference in cooked flavor emerged between groups. The authors candidly acknowledge a limitation: Chinese assessors unfamiliar with imported milk may score attributes differently from their Western counterparts, and previous cross-cultural work has shown Irish and Chinese panelists interpreting the same pasture-milk attributes in opposing ways.

Principal component analysis wove all these threads together into a single picture. Two principal components explained 56.7 and 18.2 percent of the variance respectively, and the first component cleanly separated domestic from imported milk. Domestic samples clustered tightly, characterized by higher vitamin E, fat, and n-6 fatty acids, while the imported samples scattered more widely, positively correlated with vitamin B2, n-3 fatty acids, short- and medium-chain fatty acids, long-chain fatty acids, astringency, and tea flavor. That dispersion, the researchers suggest, reflects the diversity of feeding systems, processing technologies, and storage conditions across Western European and Oceanian countries, in contrast to the large-scale standardized farming and industrial production that dominates the Chinese dairy sector.

The study concludes with practical recommendations that extend beyond shopping advice. Because average dairy intake among Chinese adults was only 27.6 grams per day in 2018, less than a tenth of the 300 grams recommended in the national dietary guidelines, the authors argue that even meeting the current recommendation would not fully satisfy needs for calcium, selenium, and vitamin B2, and they suggest that intake above 500 grams per day of milk and dairy products may be needed. They also call for exogenous vitamin A fortification, better retention of vitamins during storage and transport, and regulation of grass-fed and pasture label claims in the Chinese market, including nutrient indicators such as n-3 fatty acid content. The work was funded by the China government guides local funds for scientific and technological development under grant number 2024ZY0146, and the authors declare no competing interests. For consumers, the takeaway is refreshingly even-handed: neither domestic nor imported milk is simply better. They are products of two different agricultural philosophies, and understanding that difference is the first step toward an informed choice.

Subject of Research: Comparative nutritional composition, fatty acid profiles, and sensory characteristics of commercial UHT bovine milk from China, Western Europe, and Australia/New Zealand sold in the Chinese market

Article Title: Nutritional composition, fatty acid profiles, and sensory characteristics of commercial bovine milk from different global production regions in the Chinese market

Article References: Yang, J., Wang, M., Hu, P., Li, S., Qian, W., & Li, H. (2026). Nutritional composition, fatty acid profiles, and sensory characteristics of commercial bovine milk from different global production regions in the Chinese market. Food Science of Animal Resources, 46(1), Article 80. https://doi.org/10.1007/s44463-026-00086-5

Image Credits: AI Generated

DOI: 10.1007/s44463-026-00086-5

Keywords: UHT milk, dairy nutrition, fatty acids, pasture feeding, total mixed ration, vitamins, sensory analysis, China dairy market, omega-3, food science, milk composition, principal component analysis

The research team, led by Snigdha Homroy and Rajni Chopra at the National Institute of Food Technology Entrepreneurship and Management in Kundli, Haryana, collected discarded Tagetes erecta flowers from a local temple within six to eight hours of generation and processed them within a day to minimise the loss of volatile phytochemicals. The flowers, which had a moisture content of approximately 88 percent, were gently crushed rather than milled to preserve the delicate glandular trichomes that house the oil-bearing volatiles. From this waste stream, the researchers extracted marigold essential oil using four different approaches: conventional hydro-distillation, ultrasound-assisted hydro-distillation, freeze-thaw-assisted hydro-distillation and solvent-free microwave extraction.

The choice of extraction route proved decisive. Hydro-distillation in a Clevenger-type apparatus for four hours yielded 0.0164 grams of oil per 100 grams of fresh flowers. When the flowers were first pre-treated with ultrasound at 500 watts and 20 kilohertz, acoustic cavitation, the violent formation and collapse of microscopic bubbles, tore open cell structures and improved solvent penetration, raising the yield by roughly 25 percent. A freeze-thaw pre-treatment, in which flowers were cycled between minus 80 degrees Celsius and room temperature three times, boosted the yield by about 17 percent, because ice crystals physically rupture cell walls and membranes during freezing, enlarging the porous network available to the extracting water.

Solvent-free microwave extraction, by contrast, performed poorly in this matrix, delivering a yield 85.3 percent lower than conventional hydro-distillation. The authors attribute this to the absence of added water and the limited intrinsic free moisture of the flowers, which restricted internal heating and volatilisation of the essential oil. The result is a useful reminder that green extraction technologies are not universally interchangeable: microwave methods that excel with aromatic herbs, as previous work on rosemary showed, can falter with high-moisture, fibrous floral waste. The relatively low absolute yields across all methods also reflect the use of whole flowers, which mix oil-rich tissues with fibrous, low-oil material, and the reporting of yields on a fresh-weight basis.

Chemical profiling by headspace gas chromatography-mass spectrometry identified 41 phytochemical constituents across the oils, with a profile rich in compounds prized for antioxidant, antimicrobial and anti-inflammatory activity. Nootkatone, limonene, tagetone, piperitone, ocimene, beta-caryophyllene and isoeugenol dominated, although their proportions shifted with the extraction method. Ultrasound-assisted hydro-distillation produced the highest overall content of key volatiles, enriching oxygenated sesquiterpenes and ketones such as nootkatone, which reached 11.15 percent, while freeze-thaw treatment similarly favoured sesquiterpenes. Microwave extraction skewed toward lighter hydrocarbons and phenolics, including isopentane and isoeugenol, which contribute aroma but are less relevant to oxidative protection.

The second half of the study tested whether this waste-derived oil could defend perilla seed oil, a cold-pressed, omega-3-rich oil whose high polyunsaturated fatty acid content makes it exceptionally vulnerable to rancidity. The researchers fortified the oil with marigold essential oil at 500, 1000 and 1500 parts per million and compared the results against 200 parts per million of tert-butylhydroquinone, or TBHQ, the synthetic antioxidant benchmark, and an untreated control. Samples were then subjected to a 20-day Schaal oven test at 60 degrees Celsius, an accelerated storage protocol that compresses months of ambient shelf-life degradation into weeks by speeding the same radical chain reactions that occur in normal storage.

Across every measure, the 1500 ppm marigold treatment performed impressively. Rancimat analysis showed a statistically significant, concentration-dependent extension of the induction period, indicating delayed oxidation onset. Viscosity, which climbs as oxidation generates polymeric degradation products, rose only to 37.1 centipoise in the marigold-fortified oil, compared with 40.3 centipoise in the untreated control. The untreated oil’s peroxide value, a gauge of primary oxidation, soared to 28.63 milliequivalents of oxygen per kilogram by day 20, whereas the marigold-supplemented oil held at 10.03 and TBHQ at 9.71. Acid value, p-anisidine value and conjugated triene content, which track hydrolysis and secondary aldehyde and ketone formation, followed the same pattern, with the highest marigold dose approaching TBHQ performance throughout.

Antioxidant capacity assays reinforced the picture. Untreated perilla oil lost radical-scavenging capacity rapidly, with DPPH inhibition falling from 84.42 to 74.35 percent and ABTS inhibition from 80.15 to 66.40 percent over the storage period. The 1500 ppm marigold sample, by contrast, retained 83.86 percent DPPH and 72.94 percent ABTS inhibition after 20 days, losses of less than seven percent, comparable to TBHQ-treated oil. The oil also preserved its golden carotenoid pigments better, retaining a yellow Lovibond value of 12.2 against 9.1 for the control. Hierarchical cluster analysis of all stability parameters grouped the control and 500 ppm samples together as low-stability outliers while placing the 1500 ppm marigold oil in the same high-stability cluster as TBHQ, a statistical confirmation that the floral waste extract can match a regulated synthetic preservative at its maximum permitted concentration.

The protective mechanism stems from the oil’s constellation of bioactive volatiles, which scavenge free radicals, chelate pro-oxidant metals and interrupt lipid peroxidation chain reactions, with synergy among compounds such as beta-caryophyllene, nootkatone and isoeugenol likely amplifying the effect. The study’s significance extends beyond food chemistry. It couples two sustainability goals at once: diverting a vast, culturally generated waste stream from landfill and offering food manufacturers a clean-label alternative to synthetic antioxidants such as BHA, BHT and TBHQ, whose potential carcinogenic, genotoxic and endocrine-disrupting effects have drawn increasing scrutiny in animal and mechanistic studies. The authors note that future work should clarify the underlying preservation mechanisms and extend testing to other oxidation-sensitive oils such as flaxseed and chia. If those trials succeed, the garlands left behind at temples across India could become a genuine industrial resource, turning ritual offerings into shelf life for the world’s healthiest cooking oils.

Subject of Research: Extraction of essential oil from marigold floral waste and its use as a natural antioxidant to stabilise polyunsaturated fatty acid-rich perilla seed oil.

Article Title: Valorisation of marigold floral waste for essential oil extraction and its application in stabilisation of PUFA rich perilla seed oil

Article References: Homroy, S., Madan, H., Sharma, S., Chopra, R., & Kumari, R. (2026). Valorisation of marigold floral waste for essential oil extraction and its application in stabilisation of PUFA rich perilla seed oil. Discover Green Chemistry, 1(1), Article 16. https://doi.org/10.1007/s44509-026-00015-1

Image Credits: AI Generated

DOI: 10.1007/s44509-026-00015-1

Keywords: marigold floral waste, Tagetes erecta, essential oil, hydro-distillation, ultrasound-assisted extraction, solvent-free microwave extraction, perilla seed oil, natural antioxidants, oxidative stability, TBHQ, omega-3, waste valorisation