By Theresa Siebert, Petrus Britz, Pr Eng and Agrelek

Sunflower fat spread or margarine is prepared from sunflower oil. The spread is a water-in-fat emulsion which closely resembles butter. It is firm in a refrigerator and melts rapidly in the mouth. It is made from a non-dairy fat and water mixture.

The fat phase contains oil-soluble ingredients, for example mono- and diglycerides, lecithin (optional), colouring matter and vitamins. The aqueous phase (16 to 18%) contains water with or without added edible protein. This “milk” may be prepared by adding dried protein to water, which is then pasteurised. Pastry and kosher margarine do not contain added protein, only water.

We thank the ARC Agricultural Engineering in South Africa who made the information available to the readers of ProAgri Zambia.

Legal requirements:

In many countries, a fat spread must comply with certain requirements as well as the standards applicable for each class of fat spread like:

•It shall have a clean and pleasant flavour, be reasonably soft on the palate and be easily spreadable at 20°C.

•It shall be free of any substance that does not naturally form part of the raw material.

•The slip point of the separated fat phase shall be below 38°C.

The “fat spreads” are classified as follows:

•Yellow margarine may also be called margarine if it has a maximum milk fat content of 1% and a maximum vegetable fat content of 85%, with no marine or animal fat present. The total fat content must be between 80 and 86%, and the moisture content between 10 and 16%. A maximum salt content of 2% is allowed, a maximum fat free dry matter content of 4% and a maximum sugar content of 1%.

•White margarine has a maximum milk fat content of 1%, a maximum vegetable fat content of 85%, a maximum marine fat content of 85% and maximum animal fat of 85%. The total fat content must be between 80 and 86%, and the moisture content between 10 and 16%. The maximum salt content must be 2%, the maximum fat free dry matter content 4% and the sugar content a maximum of 1%.

•Yellow medium fat spread may also be called medium fat spread with a maximum milk fat content of 1%, a maximum vegetable fat content of 65% and no marine or animal fat present. The total fat content must be between 50 and 65%, and the moisture content is not specified. A maximum salt content of 2%, a maximum fat free dry matter content is required, and the maximum sugar content is not specified.

•White medium fat spread must have a maximum milk fat content of 1%, a maximum vegetable fat content of 65% and a maximum marine or animal fat content of com.

•65%. The total fat content must be between 50 and 65% and the moisture content is not specified. A maximum salt content of 2% is required and the fat free dry matter content and maximum sugar content is not specified.

•Yellow low-fat spread may also be called low fat spread or minarine, with a maximum milk fat content of 1%, a maximum vegetable fat content of 45% and no marine or animal fat present. The total fat content must be between 35 and 45%, and the moisture content is not specified. A maximum salt content of 2% is required and the maximum fat free dry matter content and maximum sugar content is not specified.

•White low-fat spread needs a maximum milk fat content of 1%, a maximum vegetable fat content of 45%, and a maximum marine or animal fat content of 45%. The total fat content must be between 35 and 45%, and the moisture content is not specified. A maximum salt content of 2% is required and the fat free dry matter content and maximum sugar content is not specified.

The reduced and low fat spreads cannot legally be called margarine because it contains less fat than margarine. These fat spreads contain a higher proportion of water and a blend of stabilisers and emulsifiers.

Preparation of aqueous phase for fat spreads (optional)

The aqueous phase is prepared by mixing potable water with dried protein to form a milky liquid. The milk is pumped into a temperature-controlled vat with stirrers/paddles. The mixture is inoculated with a 1% starter culture (Streptococcus cremoris, S. citrivorus) for the production op lactic acid, diacetyl and butter-like flavours. The mixture is incubated at 20 to 22°C until the pH is between 5,3 and 6,3. Ripening is not required when artificial flavouring is used.

Addition of soluble ingredients to the aqueous phase

Salt, preservatives, flavouring (optional) and colouring are added to the aqueous mixture as required. The mixture is then stored at 5 to 8°C until required.

Blending of the fat and aqueous phases

The fat (oil) and aqueous phases are pumped into weighing tanks from where it is dispensed in measured quantities to the emulsion tanks. Emulsifiers are added to the mixture at a level of 0,5% (of the fat). Emulsifiers improve the stability, texture and spreadability of the margarine. For the production of low fat and medium fat spread, stabilisers are added to compensate for the reduction in the fat content and to ensure that the water and reduced fat portions do not separate.

Emulsification of fat spread

Emulsification can be done in batch or continuous operations.

Batch process: Butter churns with the capacity to process up to 45 000 litres are used for batch operations. These churns were originally made of wood, but have since been replaced by stainless steel. The churns must be prepared to prevent the butter from sticking to the surface. Stainless steel churns must be cleaned with detergents containing silicates to maintain a “non-stick” surface. The mixture is vigorously stirred /churned in a manual churn for 10 to 20 min at 50 to 60°C until the mixture is emulsified. The mixture is then allowed to rest for a time to rest the emulsion and ensure good distribution of the added ingredients.

Continuous process: The Votator system for the manufacture of margarine is used. It produces a water-in-oil emulsion by blending about 14 to 16% water and 4% of other substances with 80% fat at 50 to 60°C. In this system, the oil phase (containing 0,1 to 0,5% of an emulsifier such as lecithin or a monoglyceride) and the aqueous phase are fed continuously by separate proportioning pumps through externally refrigerated cylinders. These cylinders are equipped with rapidly revolving coaxial shafts bearing scraper blades. Centrifugal force and the resistance to rotation offered by the mixture cause the scraper blades to bear lightly against the cylinder walls, thus giving a very high rate of heat transfer. The emulsification process is considerably promoted by this efficient cooling, since a proportion of the globules is solidified at the lowest temperatures. The whole system is enclosed.

Tempering of fat spread (optional)

A tempering phase is sometimes used for batch processing. The emulsified spread is held at elevated temperatures (22 to 36°C) for 1 to 3 days to improve the plasticity, creaming properties, and baking performance.

Cooling of fat spread

The fat spread is cooled to between 21 and 40°C (depending of the fat content) before filling.

Packaging and storage of fat spreads

Packaging is defined as the containment of a food product in a protective barrier that prepares goods for transport, distribution, storage, retailing and end-use. Brick type spreads are first moulded by filling the mixture into chilled moulds. After shaping has taken place, the bricks are removed from the moulds and wrapped in greaseproof papers or laminated films. Soft spreads are filled directly into plastic tubs. The packaging containers or materials are pre-printed or labelled. Products must be correctly labelled according to the requirements set out in the specific country’s regulations relating to fat spreads and advertising.

Legislation

The processor should be familiar with and adhere to the laws and regulations applicable to the products manufactured, to ensure the safe and legal marketing of an oilseed product.

Next month we shall look at the production of sunflower seed snacks. Published with acknowledgement to the ARC Agricultural Engineering for the use of their manuals. Visit www.arc.agric.za for more information.

LITERATURE SOURCES

1. Anon. 1993. Oil Processing: Food Cycle Technology Source Books. Intermediate Technology Publications.

2. Catsberg, CME & Kempen van Dommelen, GJM. 1990.Food Handbook. New York: Ellis Horwood.

3. Fellows, P. 1988. Food Processing Technology: Principles and Practice. Chichester: Ellis Horwood, Ltd.

4. Gunstone, F.D & Norris, FA. 1983. Lipids in foods. Oxford: Pergamon Press.

5. Jooste, C. 1998. Oliesade: Veel groter wins met nuwe proses. Landbouweekblad.

6. Light, N. 1989. Longman Illustrated Dictionary of Food Science. New York: Longman

7. Nel, C. 1998. Agrival. Agrival@netactive.co.za

8. Nickerson, JTR & Ronsivalli, LJ. 1982. Elementary Food Science. 2nd edition. Westport: AVI

9. Nwokolo, E & Smartt, J. 1996. Food and feed from legumes and oilseeds. New York: Chapman & Hall.

10. Potter, NN & Hotchkiss, JH. 1995. Food Science. 5th Edition New York: Chapman &Hall.

11. Raiken, MD; Kill, RC & Baker, C. (ed). 1998. Food Industries Manual, 24th Edition. New York: Chapman & Hall.

12. Salunkhe, DK et al. 1992. Word Oilseeds: Chemistry, Technology and Utilisation. New York: Van Nostrand Reinhold.

13. South Africa – Agricultural Products Standards Act (No 119 of 1990) and regulations. Pretoria: Government Printers

14. South African – Foodstuffs, Cosmetics and Disinfectant Act (no 54 of 1972) and regulations. Johannesburg: Lex Patria

15. Van Wyk, A. 1989. Die veelsydige sonneblom. Suid-Afrikaanse Panorama. Vol 34: # 6: pp 28 – 33.