SILFOAM SP 150 is a free-flowing food-grade silicone antifoam powder in which a polydimethylsiloxane active fluid is deposited on an inert carrier. The material is used where foam generated during reconstitution, fermentation, evaporation, or spray drying reduces equipment throughput, fill accuracy, and heat transfer. Regulatory classification is derived from FDA 21 CFR 173.340 for dimethylpolysiloxane defoaming agents, EU Regulation (EC) No 1333/2008 Annex II E 900, and the current Food Chemicals Codex dimethylpolysiloxane monograph. Industrial lot acceptance typically includes sieve residue measurement on a 75 μm screen, moisture determination by Karl Fischer titration, and a foam-knockdown comparison against an approved control sample under a defined shaking protocol. The powder should be stored below 25 °C and 60 % RH in closed polyethylene-lined fibre drums; exposure to condensing humidity causes carrier hydration and produces discontinuous dosing in screw feeders.

Why Does Cold-Water Reconstitution Create Stable Foam in High-Sucrose Beverage Powders?

The foam problem in orange-flavoured drink powders arises from air entrainment during tumble blending and from surface-active citrus terpenes released at the liquid interface. In a ribbon blender of 1,000 L working capacity, a pre-blend is prepared by mixing 0.05–0.20 g/kg SILFOAM SP 150 with a 10:1 carrier portion of granular sucrose or maltodextrin. The pre-blend is discharged through a 0.5 mm mesh classifier to break silicone-coated agglomerates before addition to the main dry mix. Blending is maintained at 20–30 rpm for 12–18 min; extended mixing beyond 25 min can shear the antifoam carrier and reduce knockdown time in cold water at 4–8 °C. In-pack foam performance is evaluated by a standardised shake test using a 250 mL graduated cylinder, 10 inversions, and foam height measured 30 s after standing. The regulatory ceiling for dimethylpolysiloxane in ready-to-serve beverages under FDA 21 CFR 173.340 is 10 mg/kg; a 1:10 reconstitution ratio keeps the final active concentration within this boundary when the batch record accounts for the declared silicone content of the powder. Finished products include instant orange drink powders, lemonade dry bases, and vitamin-fortified effervescent beverage granules. The operational boundary is dry-packaging humidity: exposure above 60 % RH for more than 2 h causes carrier hydration, bridge formation in the metering screw, and uncontrolled weight variation in stick-pack lines.

Powdered soup bases containing autolysed yeast extract, sodium caseinate, and lecithin develop a protein-stabilised foam during hot hydration in vending dispensers. The defoamer is added as a dry component to a double-cone tumble mixer with a working volume of 500 L at 0.02–0.08 % w/w of the total dry base. The sequence is critical: SILFOAM SP 150 is first dispersed into the lecithin-coated sodium caseinate fraction for 5 min at 6–8 rpm, then combined with the remaining salt, starch, and sugar fractions. This two-stage sequence prevents silicone-rich stratification in the sachet. The finished dry soup powder is filled at 22–24 °C and 35–40 % RH into metallised laminate sachets with a residual oxygen target below 1.0 %. During dispenser operation, hydration water at 80–90 °C is sprayed into the cup; foam collapse occurs within 10–15 s and allows the required fill height to be maintained without cup overflow. Under EU Regulation (EC) No 1333/2008 Annex II E 900, dimethylpolysiloxane is permitted in this powdered food category in accordance with quantum satis, but the formulator must verify national carry-over calculations for the final hot soup. A production-scale limit is the high salt content: if dry sodium chloride is added directly onto the silicone powder, localised brine formation on carrier surfaces reduces dispersibility and leads to visible white specks in the broth.

Vapour Header Entrainment in Spray Dryers Running Tomato Concentrate

Tomato concentrate at 28–30 °Bx contains pectin, cellulose, and soluble proteins that stabilise foam across the vacuum evaporator and in the spray dryer feed tank. SILFOAM SP 150 is slurried into a side stream of tomato concentrate at 0.05–0.30 g/kg of total solids under low-shear propeller agitation at 300 rpm and 60 °C. The slurry is returned to the main balance tank 15 min before the high-pressure pump. This placement avoids passage through the high-shear homogeniser at first-pass pressures above 150 bar, because mechanical attrition of the hydrophobic silica component can reduce foam knockdown in the drying chamber. The spray dryer is operated with a rotary atomiser at 15,000–18,000 rpm, inlet air temperature 170–185 °C, and outlet temperature 85–95 °C. Entrainment in the vapour header is monitored by pressure differential across cyclone separators; sustained differential above 1.5 kPa indicates foam-derived fines accumulation. The finished tomato powder is agglomerated to 0.2–0.5 mm particle size and packed under nitrogen. Regulatory compliance for tomato powder sold into the EU is assessed under E 900 and for the US under FDA 21 CFR 173.340, with particular attention to whether the final tomato powder is incorporated into a beverage, sauce, or infant formula; published data for infant-grade tomato formulations is limited and requires separate validation. The operational boundary is the acidic hot-hold step: holding the antifoam-containing concentrate above 90 °C for more than 30 min before drying can destabilise the carrier and reduce rehydration flowability.

The process-specific control parameters across the dry-mix and liquid food systems are compiled below. The table is provided as a formulation-readiness checklist, not as a universal dosing authority.

In fermented protein hydrolysate operations, the defoamer is introduced not at the hydrolysis vessel but into the neutralisation hold tank after heat inactivation of the protease. At this point the broth temperature has fallen to 55–60 °C and the protein-polypeptide foam structure is less viscous. A side-arm dispersion vessel with a pitched-blade turbine running at 250–300 rpm is charged with hydrolysed vegetable protein and SILFOAM SP 150 at 0.1–0.3 g/L of final concentrated broth. The dispersion is transferred to the hold tank over 10 min, after which vacuum deaeration at 150–200 mbar absolute reduces residual dissolved air and prevents re-foaming during subsequent concentration. The treated broth is concentrated in a falling-film evaporator with shell-side steam pressure not exceeding 0.4 MPa; foam carryover into the vapour separator is monitored by conductivity probes in the condensate line. Condensate with protein above 50 mg/L triggers an automated shutdown of the vapour compressors. The finished product is a pasteurised liquid protein hydrolysate, spray-dried into a hygroscopic powder used in savoury food applications. The regulatory limit under FDA 21 CFR 173.340 is applied to the final ready-to-eat formulation, not the concentrated intermediate; process validation must therefore include a mass-balance from the hold tank through evaporation and drying. The main incompatibility is with cationic biopolymers: chitosan-based clarification agents at pH below 5.5 can complex with the antifoam carrier and cause filter blinding on plate-and-frame units.

When Molasses-Based Yeast Propagation Broths Require Steam-Sterilisable Defoaming

Yeast propagation plants using cane molasses at 12–16 °Bx and aeration rates of 1.0–1.5 vvm experience foam formation during the logarithmic growth phase. SILFOAM SP 150 is not added to the raw molasses because the carrier can bind to calcium salts and form deposits in plate heat exchangers. Instead, the powder is slurried in sterilised water at 0.1–0.5 g/L of final broth and metered through a peristaltic pump into the fermentor headspace during the second growth stage at 30–32 °C. The addition is split into two pulses: 70 % of the dose at the onset of aeration, and 30 % when the optical density at 600 nm reaches 10–12. The foam column inside the vessel is maintained below 20 cm above the liquid surface by capacitance probes mounted at the top chord. If the probe signal remains above 80 % for more than 5 s, the control loop increases agitation from 150 rpm to 220 rpm and opens the defoamer line for 2 s. The terminal products are compressed baker’s yeast and autolysed yeast extract; sensory evaluation of the extract includes a silicon residue check against the monograph of the Food Chemicals Codex and aeration-driven volatile profiling. The operational boundary in this fermentation is antibacterial heat treatment: any stock slurry held above 4 °C for more than 24 h must be discarded to prevent microbial spoilage, and the slurry must never be autoclaved together with the molasses because the Maillard reaction products from the carrier can form foam-promoting melanoidins.

Confectionery gelatine dessert mixes rely on type A gelatine of 180–220 Bloom, citric acid, sucrose, and flavour oil. During cold-set gelation tests, protein films around air bubbles create a surface foam layer that persists after the gel sets and appears as a milky cap on the final gel. SILFOAM SP 150 is blended into the acid-sugar fraction at 0.03–0.15 g/kg of finished dry mix in a tumble blender running at 12–15 rpm for 20 min. The predispersion into acid-sugar prevents direct contact between the antifoam powder and gelatine granules, which would otherwise reduce Bloom strength and delay dissolution. The final gel is prepared by adding the dry mix to boiling water at 90–95 °C, stirring for 2 min, and cooling to 4 °C for 4 h. Foam height on the surface of a standard 150 mL gel cup is measured with a laser profilometer, with a target below 2 mm under the defined gelling protocol. Compliance is verified under FDA 21 CFR 173.340, which lists a specific limit of 16 mg/kg dimethylpolysiloxane in dry gelatine dessert mixes; the formulator must recalculate the addition rate when the dry mix is packaged into multi-serving canisters with variable scoop sizes. The production limitation is electrostatic adhesion: below 25 % RH, the silicone-coated carrier can build static charge and adhere to the inner surface of polyethylene liners, causing weight variance in the final pouch fill.

Whey protein isolate dispersions prepared at 8–12 % protein and recirculated through a high-shear mixer create persistent foam that reduces downstream plate heat exchanger efficiency. The defoamer is dispersed into a small fraction of lactose or permeate powder at 0.02–0.10 % w/w of total solids before being added to the protein dispersion tank. The tank is fitted with a radial-blade impeller at 200–300 rpm; addition is made only after the protein has been fully hydrated for 30 min at 40–50 °C. This sequence prevents competitive adsorption between the defoamer particles and whey protein at the powder surface. The dispersion is then pasteurised at 72 °C for 15 s and spray-dried at an inlet temperature of 180 °C and outlet of 80 °C. Foam in the pasteuriser balance tank is monitored by conductance level probes; a foam-induced false high level above 15 cm from the liquid surface can cause premature diversion to waste. The finished powder is used in high-protein beverage systems. Compliance under FDA 21 CFR 173.340 is determined on the ready-to-drink product; if the powder is later used as the sole nitrogen source in a medical food, the formulator must confirm whether the specific food category has a lower silicone ceiling. The operational risk is calcium bridging: hard water at >250 ppm CaCO3 can reduce the wetting of the carrier and leave visible white particles in the reconstituted dispersion.