“Lipids & Fats hold a crucial position in the realm of baked products. Their functional characteristics substantially enhance numerous quality traits desired by consumers in baked goods. Moreover, the physical and structural attributes of lipids markedly influence product characteristics. Hence, meticulous attention is essential pay attention when selecting fats and oils, as the properties of these lipids dictate their functionality within a specific product framework.”
Fats and oils, like butter margarine , cocoa butter, oils, vegetable shortenings and lard are widely used for centuries in baking. Their primary role is organoleptic – they make the bread taste, texture and appearance better.
Figure 1: Butter
Shortening can defined as the capability of fat to modify the texture of baked goods by lubricating, weakening, or reducing the elasticity of the food components’ structure, thereby contributing to a desired textural outcome in the final food product.
The major functions of shortening include:
- imparting tenderness
- confer structure
- lubricate during chewing
- improve flavor
- giving a moister mouthfeel
Fats and oils also serve a functional purpose during the transformation of dough or batter into the final baked product, so they are used to:
- easier handling
- give structure to a dough or batter
- lubricate during forming
- incorpoarate air into batters
- transfer heat
- increase melting point
- extent shelf life
The oil component of shortening provides a moist mouthfeel, tender bite, and lubrication, while the solid component of shortening aids in structuring the dough.
The suitability of shortening for a given baking application is dependent on three main factors:
- the ratio of the solid to liquid phase at a given temperature
- the crystal structure of the solid lipid
- the oxidative stability of the shortening
Water and fat compete to occupy the surface of flour particle during dough mixing. In the absence of fat, flour proteins readily hydrate with the available water, leading to the formation of an extensible gluten network. However, when shortening is introduced, it envelops starch and protein particles, segregating them and thwarting their hydration and development. This obstruction in gluten network development typically leads to reduced dough elasticity, resulting in baked products with softer textures.
The function and importance of shortening differ based on its quantity in a product formula and the specific type of product. It has been noted that shortening helps to plasticize dough, especially the gluten polymers within the dough matrix. Without shortening, adjacent gas cell bubbles merge during baking, leading to a coarser crumb structure compared to formulas with shortening. As the levels of shortening increase, the dough needs less water to achieve a comparable dough consistency
Dietary fat is an essential component of a balanced diet, having both positive and negative nutritional consequences. On the positive side, fats are crucial for energy production, absorption of fat-soluble vitamins like A, D, E, and K, and supporting cell growth. They also aid in hormone production, including hormones like insulin and stress hormones which are crucial for metabolic functions. Omega-3 and Omega-6 fatty acids, found in certain fats, are essential for brain health and inflammation control. However, on the downside, excessive consumption of fats, especially saturated and trans fats, can lead to weight gain, cholesterol elevation, and increased risk of heart diseases.
Generally, when the fat content in a traditional baked item is significantly reduced, for instance by 50%, the resulting product is often deemed to be much less desirable. A major challenge faced by bakery firms today is to minimize fat addition and explore alternative solutions without compromising the appeal of their products.
Chemical structure of fats
Fats, scientifically termed as triglycerides, are compounds composed of a glycerol molecule bonded to three fatty acid chains through ester linkages. Each fatty acid chain comprises a long hydrocarbon sequence with a carboxyl group (COOH) at one end. The nature of the bonds between carbon atoms in these chains categorizes them into:
- saturated -no double bonds,
- monounsaturated -one double bond
- polyunsaturated fats -multiple double bonds.
Saturated fats, typically solid at room temperature, are commonly found in animal products, while unsaturated fats, usually liquid at room temperature, are prevalent in plant oils. The precise arrangement and types of fatty acids significantly influence the chemical and physical properties of the fat. The double bonds in unsaturated fatty acids exhibit cis or trans configurations; the cis form leads to a bent molecular structure, representing natural unsaturated fats. In contrast, the trans form, often artificially created through hydrogenation, results in a straighter molecular structure and is associated with adverse health outcomes.
Traditional Shortenings and Tailored Fats
Traditionally, the shortenings utilized in bakery production are derived from animal products such as butter, lard, and tallow. These often impart a unique, cherished flavor appreciated by consumers. However, butter has a very narrow plastic range, becoming hard at refrigerated temperatures and almost liquid at warm room temperatures, making it challenging to handle, especially in large-scale roll-in bakery operations. On the other hand, tallow maintains a high solids content across most ordinary temperature ranges, often separating into liquid (oleo) and solid (stearine) fractions. Lard has a solid fat index profile more suitable for bread and related products, although it’s not ideal for cake making.