Review

Al222 (25419 pt) • 2025-Nov-07 14:47

Green Onion Extract Water
(aqueous extract from green onion/scallion — typically Allium fistulosum L. or young Allium cepa leaves; family Amaryllidaceae )

Description

• Clear to slightly opalescent aqueous extract obtained by maceration/infusion of chopped green onion (leaf + tender pseudostem), then clarified and heat-stabilised.
• Used as a natural savoury base for soups, broths, marinades, dressings, plant-based meats, and ready meals; can be blended with other vegetable extracts.
• Typical single-strength targets: °Brix 0.2–2.0, pH ~5.3–6.2 (low-acid food → requires validated heat treatment), turbidity from water-clear to lightly hazy depending on style and filtration.

Indicative nutrition values (per 100 ml, typical ranges; formulation-dependent)

• Energy: 0–5 kcal
• Carbohydrates: 0–1.0 g (sugars ≤0.5 g)
• Protein: 0–0.3 g
• Fat: ~0 g — SFA (saturated fatty acids; desirable to keep low overall), MUFA and PUFA negligible
• Sodium: <20 mg (naturally low; avoid added salt for “low sodium” claims)
• Potassium: 10–60 mg

Key constituents

• S-alk(en)yl-L-cysteine sulfoxides (ACSOs): methiin, isoalliin (onion-type precursors).
• Thiosulfinates & disulfides (formed post-cutting via alliinase): e.g., dipropyl disulfide and related volatiles that drive onion aroma.
• Fructans (FOS): short-chain inulin-type fructooligosaccharides (level depends on extraction strength; often low in clear styles).
• Organic acids & minerals: malate/citrate traces; K prominent among cations.
• Phenolics/flavonoids: quercetin derivatives (very low after clarification), minor chlorogenic family.
• Undesirables to control: excessive pyruvate/reactive sulfur (harshness), pesticide residues ≤ MRL, heavy metals within limits, high 5-HMF (over-heating) avoided.

Production process

• Raw material: fresh, sound green onions; trim roots; optional blanch to modulate pungency.
• Extraction: chopping/maceration in potable water (cold or mild-warm); control time/temperature and oxygen to balance fresh notes vs harsh sulfur.
• Clarification: coarse filtration → fining/flotation (optional) → polishing filtration; deaeration to limit oxidation and aroma loss.
• Standardisation: adjust °Brix/pH; optional aroma capture/return.
• Thermal processing: HTST pasteurisation and aseptic fill; or retort/sterilisation for ambient jars.
• Packaging: light/oxygen-barrier packs (bags-in-drum/IBC, pouches, or bottles) with reduced headspace (nitrogen).

Sensory and technological properties

• Colour: water-clear to pale straw/greenish tint.
• Aroma/flavour: fresh onion-leaf notes; intensity ranges from delicate to medium; heat drives sweet, lightly caramelised onion character.
• Functionality: provides natural umami-adjacent savouriness and top-notes; participates in Maillard pathways under heat; contributes slight reducing power.
• Stability: sulfur compounds are oxygen/heat-labile—flavour softens with storage; clarity holds if well filtered.

Food applications

• Soups, broths, sauces, gravies, dressings, pickling brines.
• Marinades and glazes; seasoning liquids for rice/noodles/vegetables.
• Plant-based meat systems (top-note onion flavour without particulates).
• Ready meals, snack seasoning syrups, and culinary concentrates/cubes.

Nutrition & health

Green onion extract water has minimal energy and negligible fat, so it adds flavour without materially changing calories or lipid profile. Fibre and most micronutrients are largely removed during clarification; whole green onions or purées retain more dietary fibre and phytochemicals.
The extract carries onion sulfur precursors (ACSOs) and some thiosulfinates formed on cutting. These compounds underpin characteristic flavour and, in research settings, show antimicrobial potential; in foods, their levels are modest and decline with heat and storage.
People sensitive to FODMAPs should note that fructans and sorbitol (trace) can persist into aqueous extracts—usually at low levels, but tolerance varies. Salt is not inherent; keeping added sodium modest allows low-sodium formulations.

Portion note: As a flavouring base, 10–50 ml per 200 g serving of finished food is typical; concentrate/dilution ratios should be set by sensory trials.

Quality and specifications (typical topics)

• Identity/composition: °Brix, pH, titratable acidity; pyruvate test (onion pungency index) as QA marker; total sulfur volatiles profile (where instrumented).
• Appearance: clarity (turbidity/NTU), colour (APHA/CIELAB), absence of sediments.
• Chemistry: low 5-HMF; peroxide value (if any lipid phase present) minimal.
• Residues/contaminants: pesticides ≤ MRL; heavy metals within limits; sulphites declared if used/≥10 mg/kg (generally not used).
• Microbiology: pathogens absent/25 g; aerobic plate counts, yeasts/moulds per spec; spore control via heat/aw.
• Functional tests: heat-step trials for flavour retention and colour; light/O₂ stress testing; salt/acid compatibility.

Storage and shelf-life

• Store cool, dark, and dry; avoid temperature cycling.
• Aseptic ambient packs: 6–12 months typical; frozen concentrates keep longer (≤ −18 °C; thaw cold; do not refreeze).
• After opening: refrigerate 0–4 °C and use within 3–7 days.
• Main risks: flavour fade (sulfur loss), slight yellowing, occasional haze if filtration was mild.

Safety and regulatory

• Designations: “green onion extract (aqueous)”, “spring onion extract water”, or botanical “Allium fistulosum extract (water)”.
• Category: vegetable extract for food use; low-acid if pH >4.6 — process under validated thermal schedules and GMP/HACCP.
• Allergen/intolerance notes: allium sensitivity is uncommon but reported; FODMAP considerations for sensitive consumers.
• Claims: flavouring/culinary base; nutrition/health claims generally not applicable unless fortified or compositionally qualified.

Labeling

• Name of the ingredient (e.g., “green onion extract (water)”), botanical source, and processing aids if required.
• Declare added salt, acids, or antioxidants when used; origin/lot/date marking per law.
• For clean-label positioning, indicate “no added salt”/“no added sugar” when applicable.

Troubleshooting

• Harsh/metallic sulfur notes: excessive thiosulfinates or metal contact → reduce maceration time/temperature, add chelators where permitted, avoid Cu/Fe surfaces.
• Weak flavour: over-heating or oxidation → shorten thermal hold, deaerate, use aroma capture/return.
• Browning/yellowing: non-enzymatic reactions → lower heat load, protect from light/O₂; verify low °Brix and gentle process.
• Haze/sediment: insufficient clarification → tighten filtration/centrifugation; stabilise at cold before fill.
• Micro spikes after opening: poor cold chain → improve refrigerated handling and secondary packaging.

Sustainability and supply chain

• Raw material: valorise field-trim and off-grade sizes; seasonal contracts to cut waste.
• By-products: spent onion solids to compost, animal feed, or bioenergy.
• Plant operations: heat/air recovery, CIP water reuse, wastewater treatment toward BOD/COD targets; recyclable/lightweight packs.
• Systems: supplier audits, identity/traceability, and preventive controls under GMP/HACCP.

Conclusion

Green onion extract water is a lean, clean-label flavour tool that delivers gentle scallion notes and culinary functionality with virtually no calories or fat. Product success hinges on raw-material freshness, oxygen/heat management, clarification, and protective packaging, tailored to the target intensity and application.

INCI functions (cosmetics)

• Allium Fistulosum (Green Onion) Extract / Water: skin-conditioning; antioxidant claim potential tied to phenolics; characteristic aroma (use at low levels); usage and claims subject to cosmetic regulations.

Mini-glossary

• °Brix: Percentage of soluble solids (here, mostly trace sugars/minerals); correlates with body.
• ACSOs: S-alk(en)yl-L-cysteine sulfoxides—non-volatile onion precursors that generate aroma on cutting.
• Alliinase: Enzyme that converts ACSOs to sulfenic acids → thiosulfinates/volatiles (onion flavour chemistry).
• Pyruvate test: Common index of onion pungency (μmol pyruvate/mL).
• FODMAP: Fermentable carbs that can trigger GI symptoms in sensitive individuals (onion fructans are FODMAPs).
• 5-HMF: 5-hydroxymethylfurfural, a marker of excessive heat/sugar degradation.
• MRL: Maximum residue limits for pesticides on foods.
• GMP/HACCP: Good manufacturing practice / hazard analysis and critical control points—preventive hygiene/process-control systems.
• BOD/COD: Biochemical/chemical oxygen demand—wastewater impact metrics guiding treatment.
• SFA / MUFA / PUFA: Saturated / monounsaturated / polyunsaturated fatty acids; in this extract all are negligible.

References__________________________________________________________________________

Kim SH, Yoon JB, Han J, Seo YA, Kang BH, Lee J, Ochar K. Green Onion (Allium fistulosum): An Aromatic Vegetable Crop Esteemed for Food, Nutritional and Therapeutic Significance. Foods. 2023 Dec 16;12(24):4503. doi: 10.3390/foods12244503.

Abstract. In recent years, there has been a shift towards a greater demand for more nutritious and healthier foods, emphasizing the role of diets in human well-being. Edible Alliums, including common onions, garlic, chives and green onions, are staples in diverse cuisines worldwide and are valued specifically for their culinary versatility, distinct flavors and nutritional and medicinal properties. Green onions are widely cultivated and traded as a spicy vegetable. The mild, onion-like flavor makes the crop a pleasant addition to various dishes, serving as a staple ingredient in many world cuisines, particularly in Eastern Asian countries such as China, Japan and the Republic of Korea. The green pseudostems, leaves and non-developed bulbs of green onions are utilized in salads, stir-fries, garnishes and a myriad of culinary preparations. Additionally, green onions have a rich historical background in traditional medicine and diets, capturing the attention of chefs and the general public. The status of the crop as an important food, its culinary diversity and its nutraceutical and therapeutic value make it a subject of great interest in research. Therefore, the present review has examined the distribution, culinary, nutritional and therapeutic significance of green onions, highlighting the health benefits derived from the consumption of diets with this aromatic vegetable crop as a constituent.

Puišo J, Paškevičius A, Žvirgždas J, Dimitrova TL, Litvakas A, Adliene D. Application of Red Onion Peel Extract for Green Synthesis of Silver Nanoparticles in Hydrogels Exhibiting Antimicrobial Properties. Gels. 2023 Jun 19;9(6):498. doi: 10.3390/gels9060498.

Abstract. UV-initiated green synthesis of metal nanoparticles by using plant extracts as photoreducing agents is of particular interest since it is an environmentally friendly, easy-to-maintain, and cost-effective method. Plant molecules that act as reducing agents are assembled in a highly controlled way which makes them suitable for metal nanoparticle synthesis. Depending on the plant species, their application for green synthesis of metal nanoparticles for diverse applications may contribute to the mediation/reduction in organic waste amounts, thus enabling the implementation of the circular economy concept. In this work, UV-initiated green synthesis of Ag nanoparticles in hydrogels and hydrogel's thin films containing gelatin (matrix), red onion peel extract of different concentrations, water, and a small amount of 1 M AgNO3 have been investigated and characterized using UV-Vis spectroscopy, SEM and EDS analysis, XRD technique, performing swelling experiments and antimicrobial tests using bacteria (Staphylococcus aureus, Acinetobacter baumannii, Pseudomonas aeruginosa), yeasts (Candida parapsilosis, Candida albicans) and microscopic fungi (Aspergillus flavus, Aspergillus fumigatus). It was found that the antimicrobial effectiveness of the silver-enriched red onion peel extract-gelatin films was higher at lower AgNO3 concentrations as compared to those usually used in the commercially available antimicrobial products. The enhancement of the antimicrobial effectiveness was analyzed and discussed, assuming the synergy between photoreducing agent (red onion peel extract) and silver nitrate (AgNO3) in the initial gel solutions leading to the intensification of Ag nanoparticles production.

Kumar, K. S., Bhowmik, D., Chiranjib, B., & Tiwari, P. (2010). Allium cepa: A traditional medicinal herb and its health benefits. Journal of Chemical and Pharmaceutical Research, 2(1), 283-291.

Abstract . Allium cepa is highly valued for its therapeutic properties. It has been used as a food remedy from time immemorial.Research shows that onions may help guard against many chronic diseases. That's probably because onions contain generous amounts of the flavonoid quercetin. Studies have shown that quercetin protects against cataracts, cardiovascular disease, and cancer. In addition, onions contain a variety of other naturally occurring chemicals known as organosulfur com-pounds that have been linked to lowering blood pressure and cholesterol levels.Although rarely used specifically as a medicinal herb, the onion has a wide range of beneficial actions on the body and when eaten (especially raw) on a regular basis will promote the general health of the body. The bulb is anthelmintic, anti-inflammatory, antiseptic, antispasmodic, carminative, diuretic, expectorant, febrifuge, hypoglycaemic, hypotensive, lithontripic, stomachic and tonic. When used regularly in the diet it offsets tendencies towards angina, arteriosclerosis and heart attack. This is used particularly in the treatment of people whose symptoms include running eyes and nose. The onions ability to relieve congestions especially in the lungs and bronchial tract, is hard to believe until you have actually witnessed the results. The drawing of infection, congestion and colds out of the ear is also remarkable. The onion will relieve stomach upset and other gastrointestinal disorders and it will also strengthen the appetite. Pharmacologically know as Allium cepa, onion is found in every household. The purple skinned onion tastes great. Additionally, it has several health benefits and is part of many home remedies and beauty solutions.

Lee, H. J., Lee, I. Y., Park, J. H., & Joo, N. (2025). Comparison of phytochemicals and antioxidant activities of onion (Allium cepa L.) bulbs, onion leaves, and green onion (Allium fistulosum L.) leaves. International Journal of Food Properties, 28(1), 2507121.

Abstract. Onion (Allium cepa L.) is a vegetable widely used in the culinary world. It is also remarkable as a source of nutrition and bioactive compounds. Onion leaves, which are inevitable byproducts of onion production, are morphologically similar to green onion leaves with similar taste profiles. Although they have potential as new sources of food, they are largely considered waste products. This study was conducted to investigate phytochemical compositions, quantities of phytochemicals, and antioxidant activities of onion (Allium cepa L.) leaves. Onion bulbs and green onion (Allium fistulosum L.) leaves were included for comparisons. A total of 27 phenolic compounds, predominantly flavonols, were identified from extracts of three samples, with quercetin-4’-O-glucoside and quercetin 3,7-O-diglucoside being the most significant. Hierarchical clustering analysis showed that onion leaves and green onion leaves shared distribution of bioactive compound compositions, indicating their potential as alternative food sources. Quantification results showed that: 1) onion leaves were exceptionally abundant in quercetin 4’-O-glucoside; 2) green onion leaves were more abundant in hydroxycinnamic acids, and 3) onion bulbs had relatively lower contents of analytes. Antioxidant activities of samples measured by DPPH and FRAP assays reflected quantification data, with onion leaves showing the most potent antioxidant activities. Hence, onion leaves are not only great substitutes for green onions but also have potential to provide more powerful health benefits.

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