Befar Group Food Additive Caustic Soda

Food additive grade sodium hydroxide (INS 524, E 524) from Befar Group is specified as a pH control agent, processing aid, and neutraliser in regulated food and beverage processing. The material is supplied as white flakes or as an aqueous solution, and its identity and purity are controlled under GB 1886.20-2016 and the Food Chemicals Codex monograph for sodium hydroxide. Hydroxide ion activity is the primary process variable; concentration, contact time, temperature, and matrix buffering capacity are the four parameters that determine system behaviour. Because these parameters interact differently in oil refining, cocoa alkalization, lye peeling, alkaline bakery surface treatment, table olive debittering, soy protein isolation, and caseinate neutralization, no single operating window can be transferred across processing sectors. The following applications are distinct downstream use cases, not equipment-cleaning functions, and are written from production-scale processing data.

Why Does Edible Oil Neutralization Rely on Controlled Excess Caustic Rather Than Stoichiometric Addition?

In caustic refining of crude vegetable oils, sodium hydroxide neutralizes free fatty acids to sodium soaps, which are removed from the neutral oil phase by high-speed disc-stack separators. The stoichiometric caustic demand is calculated from the acid value or free fatty acid content measured by ISO 660:2020 or AOCS Ca 5a-40, then converted to sodium hydroxide mass. Crude soybean oil entering at 0.6–1.2 wt% free fatty acid may require 0.05–0.15 wt% stoichiometric excess NaOH beyond the neutralization requirement to drive residual free fatty acid below 0.10 wt% after water washing and vacuum drying. The dilute caustic feed is typically prepared at 10–20 °Bé, corresponding to 6.7–14.2 wt% sodium hydroxide, and is heated to 70–90 °C before in-line mixing. Long-mix neutralization for seed oils uses 10–15 min of low-shear agitation before separator feed. Short-mix processes apply higher shear and shorter residence time but require more precise excess caustic control. Disc-stack separator back-pressure, soapstock discharge rate, and oil flow must be balanced to prevent soap carry-over into the refined oil stream.

The processing conflict in caustic neutralization is that excess hydroxide reduces residual free fatty acid and improves oil colour but also saponifies neutral triglycerides, increasing neutral oil loss into soapstock. The boundary between adequate neutralization and excessive saponification is usually below 0.20 wt% excess NaOH for degummed soybean oil, but published loss factors vary with feedstock phospholipid content, separator configuration, and caustic mixing intensity. After separation, residual soap in neutralized oil is reduced by water washing at 5–10 wt% water addition or by silica adsorption. The oil is then vacuum-dried at 90–110 °C and 50–80 mbar. Final acid value is verified again by ISO 660:2020. Residual sodium is monitored by flame photometry or ICP-OES to confirm that downstream deodorization does not concentrate sodium beyond the target specification. The food-grade sodium hydroxide must comply with GB 1886.20-2016. Technical-grade material containing elevated heavy metals or chlorate is excluded from edible oil refining because the soapstock may enter animal feed or acidulation circuits.

Dutch-process cocoa and cocoa liquor alkalization uses sodium hydroxide solution as one of the permitted alkaline compounds to shift the natural cocoa pH from 5.2–5.6 into the range 6.8–8.1, depending on target colour intensity and flavour profile. The treatment is carried out on nibs, cocoa liquor, or press cake in heated screw mixers or drum alkalizers. Food-grade NaOH is dosed at 0.5–2.0 wt% of nib mass as a 20–40 wt% aqueous solution, with total moisture adjusted to 20–30 wt%. Reaction temperature is held at 70–100 °C for 30–120 min. Hydroxide ion migrates into the cotyledon matrix and modifies anthocyanin and tannin colour expression. Darker cocoa powders are obtained at higher pH and longer residence time, while mid-range pH produces red-brown tones for confectionery coatings.

Because hydroxide alkalization is more aggressive than carbonate-based alkalization, it requires tighter pH monitoring and more uniform mixing to prevent localized over-alkalization. Surface over-alkalization can saponify cocoa butter at the particle interface and generate soapy off-notes. The relevant process boundary is normally set below pH 8.5 to avoid measurable free soap formation. pH is measured on a 10 wt% aqueous cocoa suspension with a calibrated glass electrode, and the final target is confirmed after roasting and milling. In the European Union, alkalized cocoa products are regulated under Directive 2000/36/EC, which permits sodium hydroxide as an alkalizing agent subject to final product composition. Published data for the exact pH threshold at which free fatty acid formation accelerates under hydroxide alkalization is limited for specific cocoa butter fractions. Plant-scale validation on the actual nib lot is required before locking dosing parameters.

Tomato and stone fruit lye peeling lines use immersion and spray systems at 5–20 wt% NaOH

Continuous lye peeling of tomatoes, potatoes, peaches, and pears exposes the fruit to heated sodium hydroxide solution to hydrolyse cuticular waxes and pectic substances in the subsurface cell wall region. The loosened skin is then removed by high-pressure water sprays or rotary brushes. In tomato peeling, caustic concentration is typically 8–15 wt% NaOH at 80–95 °C with immersion time of 15–60 s. Potato and peach lines may use 10–20 wt% at 50–95 °C for 30–180 s. Spray peelers apply lower concentration, 5–10 wt%, but achieve more uniform contact on irregular surfaces. Conveyor speed, solution circulation rate, and fruit feed mass all influence the residence time distribution. These variables must be re-validated when the fruit variety or maturity index changes.

The central process conflict is between peel removal efficiency and flesh damage. Overexposure produces cooking rings, excessive trim loss, and measurable softening of the outer flesh. Underexposure leaves peel patches that cannot be removed without manual rework. Bath concentration is maintained within ±0.5 wt% of the setpoint by titratable alkalinity checks at 15–20 min intervals and by automatic dosing of fresh food-grade sodium hydroxide. The lye tank is fabricated from 304/316 stainless steel with indirect steam jackets because dilution of concentrated NaOH is exothermic. Recirculation loops and baffles prevent stratification. After peeling, a two-stage potable water rinse reduces residual sodium on the product surface. The rinse water is neutralized with citric acid or phosphoric acid before discharge. Chemical peeling is operated as a processing aid under GMP. Final product remains subject to sodium and pH specifications defined in the plant HACCP plan. Food-grade rather than technical-grade caustic is required because the product contact surface is not separated from the edible tissue by any subsequent refining step other than washing.

Alkaline surface treatment of shaped dough pieces in pretzel, laminated, and certain hard-crusted breads is carried out before baking with a food-grade sodium hydroxide bath maintained at 3.0–4.0 wt% NaOH and 80–100 °C. Dough pieces are immersed for 5–30 s, allowed to drain, and then enter a deck or tunnel oven. The high-pH surface accelerates the Maillard reaction during baking and produces a mahogany-brown crust with a glossy, slightly chewy exterior. Surface pH after baking is usually 10.0–11.5. Crumb pH remains near 5.8–6.2 because hydroxide penetration is limited to the outer starch and protein matrix. The extent of colour development is directly linked to reducing sugar availability and surface alkalinity, not to the internal dough formulation alone.

Bath control is a production-scale bottleneck because dough pieces carry water and leached starch into the bath, diluting the caustic and increasing viscosity. In continuous pretzel lines, the bath is refreshed by bleed-and-feed to hold caustic concentration within ±0.1 wt% of the target value. Carbon dioxide from yeast fermentation acidifies the surface layer and lowers bath pH from an initial value above 13.0. If pH falls below 12.5, browning intensity and crust texture shift measurably. The bath vessel and heating coils are constructed from 316 stainless steel or alkali-compatible polymers. Aluminium conveyor components must be isolated from the alkaline environment. Sodium hydroxide use in bakery processing is covered by FDA 21 CFR 184.1763 as a general purpose food additive under GMP. Final product total sodium content is controlled through formulation and surface treatment rather than a residual hydroxide limit.

Table Olive Debittering under Alkaline Hydrolysis Conditions

Green olive processing with sodium hydroxide hydrolyses the phenolic glucoside oleuropein, reducing bitterness and making the fruit palatable. Mature green olives are immersed in a 1.5–3.0 wt% NaOH solution at ambient temperature. Lye penetration is monitored until the alkaline front reaches approximately 2/3 to 7/8 of the distance from skin to pit. Treatment duration is typically 6–14 h, depending on cultivar, size, lye concentration, and temperature. After lye treatment, the fruit is washed with potable water or diluted brine for 12–24 h to remove excess alkali and then placed in fermentation brine with sodium chloride at 6.0–8.0 wt%. The pH of the washing water and the residual sodium in the fruit mesocarp are monitored before brine inoculation.

The critical quality boundary is texture. Excessive NaOH contact hydrolyses cell wall polysaccharides and causes sloughing, blistering, or softened mesocarp that reduces commercial yield. Processors monitor lye penetration by cutting fruit at hourly intervals and applying phenolphthalein or thymolphthalein indicator to expose the alkaline front. The lye bath is reinforced daily because organic acids and atmospheric CO₂ neutralize free alkalinity, lowering the effective NaOH concentration. Final table olives must meet the product standard CODEX STAN 66-1981. Sodium hydroxide is used as a processing aid within the limits of good manufacturing practice. Residual sodium is managed by washing and fermentation brine control. Published data for cultivar-specific oleuropein degradation kinetics under varying NaOH concentration is limited. Plant-scale validation with each harvest lot is therefore required to set treatment time without exceeding the texture threshold.

Soy protein isolate production uses food-grade sodium hydroxide for alkaline solubilisation of protein from defatted soybean flakes or white flakes. The defatted material is dispersed in water at a solid-to-water ratio of 1:8 to 1:12. NaOH is metered to hold slurry pH in the range 8.5–9.5 at 55–70 °C for 45–90 min. Under these conditions, glycinin and β-conglycinin fractions become soluble and are separated from insoluble fibre and carbohydrate by decanter centrifugation. The protein-rich supernatant is then acidified to the isoelectric region near pH 4.5 using hydrochloric or phosphoric acid. The precipitated curd is neutralized before spray drying. Sodium hydroxide is also used in the neutralization step to raise the final isolate pH to 6.8–7.2. Final sodium content of the powder is controlled at this stage.

The process boundary is the rate of alkaline protein hydrolysis and lysinoalanine formation. Holding pH above 10.0 or exceeding 70 °C for extended periods reduces nitrogen solubility index, increases lysinoalanine, and darkens the isolate. Modern continuous extraction systems use in-line pH probes and automated NaOH dosing to maintain variation within ±0.1 pH. Extraction time is set by agitator torque and decanter throughput rather than fixed batch time. The spray-drying step operates at inlet temperatures of 160–190 °C and outlet temperatures of 70–85 °C. Final powder moisture and sodium content are verified by gravimetric or flame photometric methods. Nitrogen solubility index is measured by AOCS Ba 11-65 as a release criterion for isolated soy protein intended for emulsified meat and beverage applications. Food-grade sodium hydroxide meeting GB 1886.20-2016 is required to avoid heavy metal carryover into the final protein powder.

If Acid Casein Curd Is Neutralized to Produce Sodium Caseinate, Caustic Addition Must Follow pH Titration

Acid casein curd obtained from pasteurized skim milk by mineral or lactic acid precipitation is converted to sodium caseinate by neutralization with food-grade sodium hydroxide. The washed curd is dispersed in water at 15–20 wt% solids in a jacketed mixing vessel and heated to 55–70 °C. A 10–20 wt% NaOH solution is metered slowly while the slurry is recirculated through a high-shear mixer. Neutralization is stopped at pH 6.8–7.2. The resulting sodium caseinate solution is then homogenized and spray-dried. Sodium hydroxide is preferred over sodium bicarbonate when rapid neutralization is required without carbon dioxide foam formation.

The operating window is narrow because pH values above 7.5 promote browning and viscosity increase. pH values below 6.5 leave insoluble casein aggregates that reduce emulsification performance. In-line pH probes and batch titration curves are used to control the caustic feed rate. The final powder sodium content is determined by flame photometry or ICP-OES before release. For edible caseinate, protein content is determined by Kjeldahl nitrogen analysis. The food-grade caustic must satisfy GB 1886.20-2016 and FCC purity requirements to prevent heavy metal carryover. Plant-scale validation is required because curd buffering capacity varies with acid precipitation method, washing efficiency, and polymorphic protein composition.