Dr. Robert Norris, Mr. David Illingworth and the New Zealand Dairy Institute have developed a product, that helps solve the old problem of not being able to spread butter straight from the fridge.

There has been long and fierce rivalry between butter and margarine. Until recently margarine had the advantage of being easier to spread. This is no longer the case thanks to research at the New Zealand Dairy Research Institute (NZDRI) in Palmerston North.

Since the 1970s NZDRI staff have been working to develop a butter which is as spreadable as margarine and offers the consumer value for money. It is only in New Zealand that refrigerators have butter conditioners to soften butter prior to use.

Elsewhere in the world butter must be either used at fridge temperature, which is often too hard to spread, or allowed to warm and soften prior to use.

It was believed a truly spreadable butter would sell well overseas because it would overcome the major disadvantage of ordinary butter. So it proved in the UK market, when spreadable butter was launched there in 1991. In 1997 spreadable butter was first sold in New Zealand supermarkets, and it has immediately found a successful niche market.

Spreadable butter is made from the same raw materials as is all butter - cream and salt. The secret to spreadable butter lies in physically removing those parts of the cream which make ordinary butter too hard to spread at fridge temperature.

The development of spreadable butter has been a team effort. Two of the leading researchers involved at NZDRI are Dr. Robert Norris and Mr. David Illingworth.

Dr. Norris began working on spreadable butter at Palmerston North's NZDRI in the mid 1970s, and identified the key principles involved in making butter more spreadable. He and his colleagues developed a pilot-scale manufacturing process that made a very good product but which proved too expensive for commercial production.

It was not until about 10 years later that an alternative process was developed which eventually became commercially viable. Mr. Illingworth joined the group at about this time, bringing with him considerable experience in fat fractionation, which is a process used to separate fats with different melting points.

All fats are chemically similar, differing only in the proportions and types of fatty acids that make up the fat molecules. Each fat molecule contains three fatty acids combined as esters with glycerol to form what is known as a triglyceride, and the melting point of each triglyceride depends on the fatty acids present.

The presence of short chain fatty acids or unsaturated fatty acids lower the melting point of a triglyceride compared to longer chain, saturated fatty acids which raise the melting point.

Many of the vegetable oils used for frying, for example soyabean oil, contain large proportions of unsaturated fatty acids, which are liquid at ambient temperatures.

Compared with other fats, such as palm oil or olive oil, milkfat is unique because it contains the widest range of fatty acids in its make-up, and hence has a very wide melting range- from -40 C to +35 C.

During the manufacture of spreadable butter, milkfat is cooled to a temperature at which some of the higher-melting triglycerides form crystals, which are then physically removed.

Certain triglycerides melt between fridge temperature and room temperatures, and have been found to have the greatest effect on butter spreadability. Once these have been removed, the remaining triglycerides will give consistent butter spreadability over the temperature range experienced by your butter from the fridge to your sandwich.

At about the time that a spreadable butter was produced by this process on the NZDRI pilot plant, market research in the UK identified a major opportunity.

A global industry project team was immediately established, which included members from New Zealand Dairy Board, Bay Milk Products ,who are now part of the New Zealand Dairy Group, Anchor Foods Ltd, a subsidiary of the NZDB in the UK, and NZDRI.

This team was charged with bringing spreadable butter to full commercial production, and included automating the manufacturing process as far as possible.

The global industry product team did this between September 1990 and July 1991 when production commenced at Te Puke in the Bay of Plenty. The success of spreadable butter in the UK led to that plant being expanded and moved to its current location at Anchor Products Edgecumbe. Projections of sales to the end of the century and the opening of new world markets resulted in a second plant being constructed at the Kauri factory of the Northland Dairy Company.

The NZDRI team helped to train the plant operators and work with the dairy company to ensure the plant would meet the necessary production targets and specifications. Mr. Illingworth said the impetus to develop new butter products such as spreadable butter originally came in the 1970s when Great Britain joined the European Community and no longer guaranteed to buy all the butter we produced.

This led to the development of spreadable butter. The development process also showed the importance of teamwork and a mix of skills to achieve success. So, not only chemists like Dr. Norris and Mr. Illingworth were involved, but engineers, food technologists, dairy plant operators and consumer marketers were all important.

Dairy Board spokesperson Allison Mac Gillivray explained the value of spreadable butter as follows: "By adding value to a standard product, by making it more useable, or better for people, you can sell it for a higher price and therefore get more returns for the New Zealand dairy industry."