Fats and Oils

Its simple - fats are essential for life. We need them to survive. Why are they so important? Their jobs are many and varied and include; the maintenance of skin & hair, protecting our body organs against shock, maintaining the appropriate body temperature, the absorption of Vitamins A, D, E & K, aspects of reproduction & immune function. Essentially the cycle of making, breaking, storing and mobilising fats is how we regulate our energy. 

yo1400011I believe fats are also essential for baking.

Why are they so important? Their presence in baked goods for example can; contribute flavour, carry flavour, enhance mouthfeel, contribute to texture, & preserve freshness. 

Fats belong to a larger group of substances called lipids. Fats are usually solid at room temperature (220 C) and oils are fats that are usually liquid at room temperature. All fats, regardless of whether they are solid or liquid are derivatives of fatty acids and glycerol (triglycerides). Triglycerides can be described as being shaped like an E. The glycerol is the backbone of the E and the fatty acid, 3 of them, are the arms.

Whether a fat is solid or liquid and therefore its melting point will depend on; how long the fatty acid is and how “saturated” it is. Saturation of a fatty acid refers to whether it is “saturated” with hydrogen atoms. Saturated fats have a full complement of hydrogen atoms with regards to their carbon backbone (the arms of the E). All carbon bonding in the carbon backbone of a saturated fat are single bonds. When there is one double bond between two carbons in the backbone the corresponding fat is termed monounsaturated. Two of the carbon atoms do not have a full complement of hydrogen atoms. Polyunsaturated fats contain two or more double bonds in the carbon backbone. As such polyunsaturated fats do not have a full complement of hydrogen atoms. The majority of saturated fats are solid at room temperature while monounsaturated & polyunsaturated are liquids.

Most fats and oils, regardless of whether they are from plants or animals, contain all 3 types of fats (Graph below - Comparison of Fats & Oils). The information was sourced from either Food Standards Australia New Zealand, using the NUTTAB database www.foodstandards.gov.au/science/monitoringnutrients/nutrientables/nuttab or USDA National Nutrient Database for Standard Reference www.ars.usda.gov/nutrientdata. I have included nuts as they are a wonderful source of oil and can be used extensively in baking. For similar reasons I have included dairy and coconut creams. The difference between fats/oils from different sources lies in the lengths of the carbon backbone of the three fatty acids, whether they are saturated, monounsaturated or polyunsaturated, and the relative amounts of each.  Animal fats usually have a high proportion of saturated fats. Some nuts contain the lowest levels of saturated fats whilst coconut oil contains the highest.

Usually it is easier for baking to use a solid fat (saturated) particularly for pastries in addition solid fats have a longer shelf life than polyunsaturated fats. Fats can go “off” or become rancid. One of the ways fats become rancid is by oxidation (exposing them to oxygen, ie. air). It is primarily the polyunsaturated fat component of fats that are most susceptible to oxidation. The ease of use & extended shelf life are two of the reasons that the food industry introduced hydrogenated vegetable oils. The process of hydrogenation “saturates” the polyunsaturated fat with hydrogen atoms and turns it into a saturated fat. However, if the hydrogenation process is incomplete the resulting fat will be partially hydrogenated and will contain trans fats (not all the carbon carbon double bonds have been converted to single bonds). Most countries require food labelling to include the level of trans fats present in products.

There is a lot of information on the web regarding the health benefits of certain fats or the implication of other fats in diseases. As such I will focus on the relevance of fats in baking. Some fats are fantastic for baking while others are not. So how do you choose which fat to use? There are plenty of reasons to choose a specific fat and include;

crunchiesandwich500011Flavour: Coconut cream, peanuts, butter

Mouthfeel: Cocoa butter

Health: Walnuts, Flaxseed oil (The oils are rich in alpha-linolenic acid, an omega-3 fatty acid)

Ease of use: Butter

Dietary: Nuttelex (a dairy free margarine)

 

 

Two fats, butter & cocoa butter, get a special mention because quite simply I think they are wonderful.

Butter

Normally fats and oils don’t mix with water. To get them to mix you need to have an emulsifier. For example a shaken vinaigrette, containing an acid (vinegar, lemon juice) and oil, when left will separate into two layers. Mayonnaise may contain the same acid & oil as the vinaigrette but it also contains egg. In this case the egg is an emulsifier and the acid & oil have mixed (& stay mixed) to form a creamy mayonnaise. A protein (lecithin) present in the egg yolk is the emulsifier.

What does this have to do with butter?    

Butter is an emulsified solid containing approximately 80% fat and 15% water. Butter naturally contains 1% protein and it is this protein that acts as an emulsifier. This means that it is possible to dissolve ingredients that normally wouldn’t dissolve in fat, for example sugar, in the water contained in the butter. Essentially this is what is happening when you cream butter and sugar. Creaming together butter and sugar is the first step in a lot of cake and biscuit recipes. As the mixture is beaten sugar will dissolve and the mixture will become smoother. Other ingredients that contain a high water percentage can also be incorporated into butters relatively easily. Flavoured butters whether they be savoury (garlic or herb) or sweet (coffee cream) are easily made because butter is an emulsified solid.

The temperature range that a fat melts is also important for baking. In the final product it will contribute to mouthfeel. A fat that has a high melting temperature range (for example above 450 C - suet) will be solid in your mouth when you eat it. Although the fat will be dispersed in the product sometimes it feels like your mouth has been coated with it. A feeling I do not like. Butter literally melts in your mouth. It has a melting temperature range of 32 – 350 C; a smidgeon below normal body temperature.    

Of course the flavour of butter also contributes favourably to baked goods.

Cocoa butter or Cacao butter

I’ll admit it, I am a chocoholic. I love the silky texture and the balance between sweetness & bitterness in dark chocolate. I find it delicious. The silky texture, creaminess or melt in the mouth quality of good chocolate is due to the presence of cocoa butter.  Chocolate that contains fats other than cocoa butter simply do not give the same mouthfeel when they are eaten. As it is with butter, cocoa butter literally melts in your mouth. The melting temperature range for cocoa butter is 34 – 36.50 C.

In addition cocoa butter is a very stable fat and can be stored at room temperature (well, those rooms that are below its melting point – my sisters kitchen has been known to reach 380 C!).