Foam Control in the Food & Beverage Industry

The role of PAG foam inhibitors in AQUEOUS refinement and processing APPLICATIONS

Processing in food and beverage applications is a formidable task. Manufacturers can be faced with narrow windows and complex, multi-stage processes that need to run 24 hours a day. So, when a problem like foam interferes, it is vital that plant managers act decisively. Here, Dr Liz Dixon, Global Technology Director at Shrieve, a supplier of differentiated specialty lubricants and performance fluids, explains how concentrated PAG foam inhibitors hold the answer.

Foam is an unwanted problem for plant managers in many food and beverages processing applications, such as sugar beet, potato, juice and other starch-rich applications. Not only does it reduce the processing efficiency, but it can also clog equipment, leading to unscheduled downtime for equipment cleaning. In a continuous and mission-critical process such as this, manufacturers cannot afford to lose time or money.

Traditional foam control

In the past, plant managers have employed a variety of measures to tackle foam, even resorting to manually agitating the foam to break it down. Today, most plants use some form of chemical foam control. Whether they’re referred to as defoamers, anti-foamers or foam-controlling agents, most products on the market do one of two things; they either break down the surface foam that forms or prevent the foam from forming in the first place.

In theory, all these products work to reduce the surface tension of the bubbles that make up the foam, weakening the structure and forcing it to collapse. In practice, however, adding almost any liquid to water will reduce surface tension to some degree. As a result, the market is filled with products that use everything from cheap fatty acids and emulsions of mineral oil, to alcohol, silicones and esters, promising to eliminate foam. 

Because end users rarely source these foam control agents directly from the manufacturer, the market has a multitude of third-party formulators and blenders, companies that often dilute the agents with up to fifty per cent water. The results are products that are cheaper to buy per unit, but whose performance may be far less effective.

PAG concentrates

As an expert in synthetic chemistry technologies, Shrieve has made it a core part of its strategy to market a product that delivers high-performance foam control. This resulted in the development of the PROGILINE FI portfolio of 100 per cent active polyalkylene glycol (PAG) concentrated foam inhibitors. The range consists of several products, which are designed specifically for the defoaming and suppression of foam in various stages of processing.

The products work by mimicking the molecules contained in the bubbles that make up the foam. We’ve designed parts of the structure of the PROGILINE FI molecules to make them resemble molecules, such as saponin which occur naturally in sugar beet for example, which means that when PROGILINE FI is dosed into the system, its molecules line up with the naturally occurring ones within the bubble wall.

However, because the PROGILINE FI molecules are not structurally identical to the saponin ones, they destabilise the structure of the bubble wall, ultimately causing the foam to break down.

Understanding temperature

Processing temperatures can vary drastically from one stage of processing to the next, and not all foam control agents work well at all temperatures. Although many will generally work well at high temperatures, they will deliver poor performance in colder conditions. Many processing facilities consist of both colder and warmer processes where foam is an issue.

To solve this, we’ve designed the PROGILINE FI portfolio to work at specific ranges of temperature according to the intended application. This makes products in the portfolio ideal for everything from the colder stages to hot stages such as diffusion processes, where water temperatures can typically reach 50–90 degrees Celsius.

At the same time, PROGILINE FI remains inactive until it reaches the correct temperature. For example, our PROGILINE FI 50100 grade is soluble in water at lower temperatures, with an aqueous cloud point — the temperature at which the product comes out of solution in water — of just below its active temperature of 50 degrees Celsius. This means that it remains soluble at low temperatures but delivers maximum performance when it reaches the desired temperature range.

The concentrated nature of the product also means that very low dosages are required to deliver this performance. Where plant managers may need to hold large volumes of diluted foam control agents, with PROGILINE FI they only need to hold a small volume, with a typical dosage rate falling between 5–20ppm. For food environments, PROGILINE FI is also safe to use, being kosher and halal approved, as well as being FDA compliant.

Fight the foam

With the right choice of concentrated PROGILINE FI PAG foam inhibitor, plant managers can not only ensure defoaming and antifoaming properties, but they can also do so at a temperature of their choice. In doing so, the challenges associated with food and beverage production applications just became a lot easier.


Liz Dixon
Global Technology Director, Shrieve