HCl in Food-Grade Gelatin Production — Hydrolysis Process & Quality Standards
Table of contents
TL;DR: Food-grade HCl (pharmaceutical, FCC/USP) is the hydrolytic agent that breaks down collagen from animal skin, cartilage and bones to produce gelatin — an essential food hydrocolloid used in candies, yogurt, and soft capsules. The acid process for type A gelatin: soak raw material in HCl 1–6% for 10–30 hours, wash, extract gelatin at 50–70°C. Food gelatin standards: heavy metals <10 ppm, arsenic <1 ppm, E. coli negative. Loc Thien Chemical supplies HCl 32% meeting FCC standards for gelatin production — batch COA/MSDS, nationwide IP delivery.
HCl in Gelatin Production — The Role of Collagen Hydrolysis
Gelatin is a partially hydrolyzed product of collagen — the main structural protein in animal skin, bones, and cartilage. HCl breaks the intramolecular and intermolecular cross-links of collagen, converting insoluble collagen into water-soluble gelatin.
Mechanism: H⁺ ions from HCl attack peptide bonds and cross-links between collagen fibers, cutting the triple helix network into individual α, β, and γ chains — gelatin that dissolves in hot water and forms a gel upon cooling.
This method is called the acid hydrolysis process, producing type A gelatin (isoelectric point pI 7–9) — as opposed to the alkaline method for type B gelatin (pI 4.8–5.2).
Comparison of Type A (Acid) and Type B (Alkaline) Gelatin:
| Parameter | Type A Gelatin (Acid) | Type B Gelatin (Alkaline) |
|---|---|---|
| Hydrolytic agent | HCl, H₂SO₄, H₃PO₄ (1–6%) | NaOH, Ca(OH)₂ (lime) |
| Main raw material | Pig skin, chicken skin | Cattle bones, cattle hide |
| Pretreatment time | 10–30 hours | 3–16 weeks (liming) |
| Isoelectric point (pI) | 7–9 | 4.8–5.2 |
| Bloom strength | 200–300 g | 150–250 g |
| Main application | Food, soft capsules | Dairy, confectionery |
| Product pH | 3.8–6.0 | 5.0–7.5 |
Advantages of the acid method: much shorter processing time (10–30 hours vs 3–16 weeks), easier process control, and higher Bloom strength product. Disadvantage: raw material must be clean with few impurities because the acid process does not remove impurities as effectively as the alkaline method.
Gelatin Production Process from Animal Skin Using HCl
Step 1: Raw Material Preparation
Raw materials (pig skin, cattle hide, bones, chicken cartilage) are cleaned — removing fat, excess meat, and impurities. For bones: crush to 1–3 cm size, degrease with hot water or solvent. Pig skin: cut into 5–10 cm pieces, wash clean.
Step 2: Acid Soaking (HCl) — Pretreatment
This is the decisive step. Raw materials are soaked in HCl solution at concentrations:
- Pig skin: HCl 1–5%, time 10–30 hours, room temperature (20–25°C)
- Chicken/pig bones: HCl 3–6%, time 24–48 hours
- Buffalo hide: HCl 0.9M (~3%), 24 hours
Optimal HCl concentration and soaking time depend on raw material thickness. Research on chicken bones (Kadarani & Jannah, 2022) shows HCl 6% soaking for 24 hours yields the highest gelatin yield (>8% wet weight) with Bloom strength of 260.57 g. Research on buffalo hide (Mulyani et al., 2017) determined HCl 0.9M (~3%) as the optimal concentration for the highest yield of 29.17%.
Step 3: Washing and Neutralization
After acid soaking, the raw material is thoroughly washed with clean water to pH 5–7. Purpose: remove residual Cl⁻ ions, stop further hydrolysis. pH can be adjusted with dilute NaOH.
Step 4: Hot Water Gelatin Extraction
The neutralized raw material is heated with water at:
- 1st extraction: 50–55°C for 3–4 hours — first-run gelatin, high quality
- 2nd extraction: 60–70°C for 3–4 hours — medium gelatin
- 3rd extraction: 75–85°C for 4–6 hours — final gelatin, lower quality
Total extraction time 10–15 hours. Each batch is collected separately — first-extraction gelatin has the highest Bloom strength, used for applications requiring strong gel.
Step 5: Filtration, Concentration, Drying
Gelatin liquor is filtered (removing fat and insoluble impurities), vacuum-concentrated, spray-dried or chill-dried into gelatin powder. Finished product has 8–12% moisture, >85% protein, pH 4.5–6.0.
Figure: On-site chemical dosing, storage tank operation, and batch COA inspection — Source: Loc Thien Chemical.
Food-Grade HCl Standards for Gelatin Production
HCl used in food gelatin production must meet FCC (Food Chemicals Codex) or USP (United States Pharmacopeia) standards. Key specifications:
| Parameter | FCC/USP Standard | Significance in Gelatin Production |
|---|---|---|
| HCl content | 36.5–38.0% (concentrated solution) | Standard commercial grade |
| Heavy metals | <10 ppm (as Pb) | Ensures food safety |
| Arsenic (As) | <1 ppm | FDA 21 CFR limit |
| Iron (Fe) | <5 ppm | Prevents oxidation discoloration of gelatin |
| Sulfate (SO₄²⁻) | <5 ppm | Prevents calcium sulfate precipitation |
| Residual volatiles | Per TCVN | Limits organic impurities |
| Appearance | Clear solution | No turbidity, no mechanical impurities |
Technical-grade HCl must not be used for food gelatin production — its heavy metal content is many times above permitted limits and can introduce lead, arsenic, and mercury into the final product.
🛒 Need food-grade HCl? Get a quote for HCl 32% food grade — COA/MSDS, FCC. Hotline 0979 891 929.
Factors Affecting Gelatin Quality
HCl Concentration
Increasing HCl concentration improves hydrolysis yield — but too high (>6% for skin, >1.2M for buffalo hide) causes over-hydrolysis, cutting gelatin chains too short, reducing Bloom strength and viscosity. Research on buffalo hide: HCl 0.9M (~3%) gave the highest yield of 29.17%; HCl >0.9M reduced yield due to protein loss during washing.
Soaking Time
24-hour soaking gives higher yield than 48-hour soaking on chicken bones (Kadarani & Jannah, 2022). Longer soaking may increase Bloom strength (265.69 g at 48h vs 260.57 g at 24h) but reduces overall yield. Optimizing soaking time is a key factor in process design.
Extraction Temperature
High extraction temperature (>75°C) increases yield but reduces Bloom strength due to over-hydrolysis. Multi-stage extraction — gradually increasing temperature from 55°C to 75°C — allows maximum gelatin recovery while maintaining quality in the early batches.
Loc Thien Supplies HCl 32% Meeting Gelatin Production Standards
Loc Thien Chemical supplies HCl 32% (density ~1.16 g/ml) meeting FCC/USP standards — suitable for food and pharmaceutical gelatin production. Each shipment includes:
- COA (Certificate of Analysis) — actual test data: HCl content, density, heavy metals, As, Fe
- MSDS (Material Safety Data Sheet) — full safety instructions
- Audit support: COA/MSDS and other documents can be provided on request for a customer’s audit
- QC verification: Phan Cam Thuy and Vo Thi Nhu Hoa are responsible for quality control of each shipment before dispatch
Loc Thien operates 6 warehouses nationwide (Ba Ria – Vung Tau, Dong Nai, Binh Duong, Da Nang, Can Tho and Bac Ninh) with a fleet of 5–30 ton tankers — delivery within 4h in Ho Chi Minh City, 24–48h to Southern industrial parks.
Anonymous case study: A gelatin plant in Dong Nai province switched from technical-grade HCl to Loc Thien’s HCl 32% FCC grade. Result: heavy metal content in the gelatin product dropped from 18 ppm to below 5 ppm (ICP-MS analysis), meeting Japanese export standards. The plant eliminated one additional refining step thanks to cleaner input material.
Technical Support & B2B Procurement Hotline
Loc Thien Chemical specializes in direct manufacturing of FeCl₂ / FeCl₃ and direct industrial supply of basic chemicals (NaOH, HCl, H₂SO₄, PAC, NaOCl, H₂O₂, FeSO₄) with direct B2B pricing and dedicated 5–30-ton tanker delivery across Vietnam.
- Hotline / Zalo: +84 979 891 929
- Official Email: [email protected]
- Direct Manufacturer: Ferrous Chloride (FeCl₂ 30%) & Ferric Chloride (FeCl₃ 38–40%)
- Primary Supplier: NaOH 32%/45%/50%/99%, HCl 32%, H₂SO₄ 98%, PAC 30–31%, NaOCl 10–12%, H₂O₂ 35%/50%
- Compliance & Quality: FeCl₂ ZDHC MRSL v3.1 test report (Smart testing, 5 substance groups, TUV Rheinland Vietnam), ISO 9001:2015, Quatest 3, Full COA & GHS SDS
Frequently Asked Questions (FAQ)
How are Type A and Type B gelatin different?
Type A uses acid (HCl), fast process, high Bloom, used for food and capsules. Type B uses alkali (lime), long process, lower Bloom, higher product pH.
What HCl concentration is used for gelatin production?
Typically 1–6% depending on raw material — pig skin 1–5%, chicken bones 3–6%, buffalo hide ~3% (~0.9M). Excessively high concentration causes over-hydrolysis and reduces gel quality.
Why must food-grade HCl be used instead of industrial HCl?
Industrial HCl has high heavy metal content (lead, arsenic, iron) that contaminates the final product — exceeding the FDA limit of 10 ppm.
What is the optimal HCl soaking time?
Research shows 24 hours is better than 48 hours for chicken bones — higher yield, though Bloom strength may be insignificantly lower.
What is the best gelatin extraction temperature?
Multi-stage extraction 55°C → 65°C → 75°C maximizes yield. Avoid extraction above 90°C, which degrades gel strength.
What documents does Loc Thien provide with HCl 32% for gelatin?
Every batch comes with a COA and MSDS, and documents can be provided on request for a customer’s audit. The food quality of the HCl is judged against FCC/USP and the batch COA, not against ZDHC. Loc Thien holds official ZDHC MRSL v3.1 Conformance Level 1 documentation for 9 flagship products (TÜV SÜD #ZDHC1 127736 0001–0004: NaOH, H₂O₂, Na₂SO₄, Na₂CO₃; TÜV Rheinland #248162921-01–05: H₂SO₄, FeCl₂, HCl, NaOCl, PAC 31%).
Does HCl 32% need dilution before soaking raw materials?
Yes, HCl 32% must be diluted to working concentration (1–6%). Use full PPE when diluting — always add HCl slowly to water, never the reverse.
Request a Quote
Contact Loc Thien Chemical — supplying HCl 32% food grade for gelatin production, meeting FCC/USP standards, with batch COA/MSDS. Hotline 0979 891 929.
Industrial Field Operation & Batch Quality Verification
1. Incoming Batch COA Verification & Regulatory Compliance (Law on Chemicals 69/2025/QH15)
When operating industrial water treatment, surface finishing, or textile dyeing lines in Vietnam, engineering teams must verify every chemical delivery against its batch-specific Certificate of Analysis (COA) and 16-section GHS Safety Data Sheet (SDS). Under the Vietnam Law on Chemicals No. 69/2025/QH15, Decrees 24/2026/ND-CP, 25/2026/ND-CP, and 26/2026/ND-CP, and QCVN 40:2025/BTNMT on industrial wastewater discharge:
- Specific Gravity & Assay Verification: Upon arrival of a 5–30-ton tanker or IBC tote shipment, plant QA technicians measure specific gravity at 20 °C using a calibrated hydrometer and cross-check active concentration against the batch COA issued by Loc Thien Chemical and verified via Quatest 3 (ISO/IEC 17025).
- Impurity & Heavy Metal Control: Trace heavy metals (Fe, Pb, As, Hg, Cd, Cr⁶⁺) and insoluble matter are strictly controlled to prevent catalyst poisoning in Fenton reactors, membrane fouling in RO/UF systems, or shade deviations in reactive textile dyeing.
- ZDHC MRSL v3.1 Level 1 Portfolio Boundary: For export-oriented textile and footwear FDI factories, Loc Thien Chemical maintains official ZDHC MRSL v3.1 Conformance Level 1 documentation for exactly 9 core products: four products certified by TUV SUD Product Service GmbH (
NaOH,H2O2,Na2SO4,Na2CO3) and five products verified via Conformance Summary Report (CSR) and Analytical Test Report by TUV Rheinland Vietnam (H2SO4,FeCl2,HCl,Javel/NaOCl,PAC 31%).
| Control Stage | Inspection Parameter | Test Method / Standard | Operational Target |
|---|---|---|---|
| Pre-Unloading Check | Seal integrity, UN/GHS hazard placards, batch COA & SDS | Visual & Document Audit | 100% match with delivery manifest |
| On-Site Sampling | Specific gravity (20 °C), visual clarity, pH / assay | ASTM / TCVN / Hydrometer | Within ±0.5% of COA specification |
| Dosing Skid Calibration | Metering pump stroke & frequency, back-pressure valve, ORP/pH probe | 2-Point Buffer Calibration | Dosing accuracy ±1.5%, stable effluent |
| Storage Safety Audit | HDPE/FRP tank vents, secondary containment dike (110% volume), eyewash | OSHA / Vietnam EHS | Zero vapor leak, immediate emergency readiness |
2. Dosing Optimization, Storage Materials & Preventive Maintenance
- Compatible Wetted Materials: Use cross-linked high-density polyethylene (XLPE / HDPE), polypropylene (PP-H), fiberglass-reinforced plastic (FRP with vinyl ester resin), or PTFE/PVDF-lined piping depending on corrosive and thermal conditions. Avoid unlined carbon steel or incompatible elastomers.
- Automated Dosing Control: Integrate diaphragm metering pumps with real-time pH, ORP (mV), turbidity, or conductivity sensors. Always perform a 5-beaker Jar Test whenever raw water COD, TSS, or alkalinity shifts by more than 15%.
- Secondary Containment & PPE: Storage tanks must sit inside an acid/alkali-resistant bund wall holding at least 110% of the largest tank volume. Operators handling unloading hoses must wear splash-proof chemical goggles, acid/alkali-resistant nitrile or neoprene gloves, face shields, and emergency respirators.
3. Multi-Role B2B Value Matrix (Procurement · QA/EHS Engineer · Plant Director)
- For Procurement Managers: Loc Thien Chemical is the direct manufacturer of FeCl2 30% solution and FeCl3 38–40% wastewater grade (3,000+ tons/month capacity), and a Tier-1 bulk commercial supplier of NaOH, HCl, H2SO4, PAC, NaOCl, H2O2, FeSO4, and Na2SiO3. Pricing is transparently structured around 5 technical cost drivers (active assay, packaging format, delivery distance from our 6 warehouses, order volume, and scheduled contract cadence) with a 15-minute technical quotation SLA.
- For Environmental & Process Engineers: Full technical support for Jar Test optimization, stoichiometry calculation, sludge minimization, and QCVN 40:2025/BTNMT compliance auditing.
- For FDI Plant Directors: Guaranteed supply continuity via 6 regional warehouses (Ba Ria - Vung Tau, Dong Nai, Binh Duong, Da Nang, Can Tho, Bac Ninh) and a dedicated 5–30-ton tanker fleet (4 hours in inner HCMC, 24–48 hours across Southern & Mekong Industrial Parks, 2–3 days in Northern & Central Vietnam).
4. Related Technical Resources & 15-Minute Quotation Gateway
- Explore our full industrial catalog: Industrial Chemical Catalog | Technical Knowledge Hub | Request a 15-Minute Technical Quote
- Legal Head Office: 452/6B Tinh Lo 10, Binh Tri Dong Ward, Binh Tan District, Ho Chi Minh City, Vietnam (Head Office only — all physical stock is dispatched from our 6 regional industrial park warehouses).
- 24/7 Technical Hotline: 0979 891 929 (Please contact hotline 0979 891 929 for detailed delivery procedures) | Official Email: [email protected]