Hardness or Firmness: Shorter or more unsaturated fatty acids characterize fats and oils that are soft or liquid at room temperature while solid fats contain large amounts of long chain and saturated fatty acids.

Melting point: Fats and oils of shorter and more unsaturated fatty acids melt at lower temperature than those with longer and more saturated fatty acids

Solubility: Fats and oils are not soluble in water but are soluble in organic solvents like ether, chloroform, benzene, hot alcohol, hot acetone and carbon tetrachloride. The solubility in Sodium hydroxide is due to saponification.

Odor, taste and color: In the pure state, fats and oils are odorless, tasteless and colorless.

Reaction to litmus paper: Fresh fats and oils are neutral to litmus. Rancid fats and oils are acidic to litmus due to the formation of volatile fatty acids.

Greasiness: Neutral fats and oils have a characteristic greasy feel and produce a transluscent spot when in contact with paper.

Specific gravity: The specific gravity of all fats and oils is less than 1 g/ml, therefore all fats float in water.

Crystallization: Some fats and oils produce characteristic crystals with definite melting points which serves to differentiate them from one another

HYDROGENATION - This refers to the addition of hydrogen atoms to unsaturated fat molecules converting carbon-to-carbon unsaturated (double) bonds to saturated (single) bonds.

Nickel - In the laboratory, this hydrogenation is done by introducing hydrogen gas bubbles to the heated oil in the presence of a _____ catalyst.

Oxidation of Fats and Oils – other name for randicity

RANCIDITY - A fat or oil becomes rancid when its double bonds are oxidized in the presence of oxygen in air at room temperature turning the unsaturated fatty acids into volatile aldehydes, ketones and carboxylic acids that changes the flavor of these triglycerides and emit disagreeable odors. But, saturated fats are more resistant to oxidation, therefore less prone to rancidity.

lipoxidase - The presence of an enzyme, ______, and such agents like heat, light, moisture and bacteria contribute to the  rapid onset of rancidity.

butylated hydroxyanisole – What is BHA?

butylated hydroxytoluene – What is BHT?

HYDROLYSIS  - Fats and oils are readily hydrolyzed by strong acids and digestive enzymes called lipases in the presence of water. The products of hydrolysis are glycerol and three fatty acids. The polar glycerol is soluble in water, but long-chain fatty acids are not.

SAPONIFICATION - This is the process when a fat is heated with a strong base such as sodium hydroxide or potassium hydroxide. This alkaline hydrolysis will yield glycerol and sodium salts of fatty acids called soaps.

SAPONIFICATION  - Formation of insoluble soaps in the intestinal tract in some abnormal conditions characterized by poor fat absorption such as sprue, can lead to significant calcium losses.

EMULSIFICATION - It is the process of dispersing fat as tiny fat globules which are suspended in another liquid with the help of an emulsifying agent. Bile salts and lecithins are essential emulsifiers in digestion and absorption.

ACROLEIN FORMATION - Excessive heating of fats leads to the breakdown of glycerol, producing a pungent compound called acrolein (2propenol) which is irritating to the gastrointestinal tract mucosa

60 to 150 g - An adult ingests about _______ of lipids per day,

MOUTH: Hydrolysis of lipids does not occur because the lipids is not yet emulsified but lingual lipase secreted by the salivary glands degrades only the triglycerides at the lipid-water interface to form a fat bolus.

lingual lipase - secreted by the salivary glands

Gastric lipase - can only degrade triacyglycerol molecules containing fatty acids of short or medium chain length at neutral pH and is therefore of little or even no use in the adult stomach where the pH is low.

SMALL INTESTINES: True digestion of lipids starts at the small intestines.

bile salts - In the duodenum, triacyglycerol molecules are emulsified or solubilized by mixing with ______

pancreatic lipase - In the jejunum, emulsified fats are then degraded by ________ to produce two fatty acids and monoacylglycerol molecules

Liver - is the main organ which regulates fat metabolism and is largely responsible for the regulation of lipid levels in the body.

LIPOLYSIS - refers to the degradation of fat stores or triglycerides into glycerol and fatty acids by the aid of enzymes known as lipases.

Lypolysis - This occurs when energy reserves are too low like during fasting, vigorous exercises and in response to stress.

KNOOP’S BETA OXIDATION - refers to the degradation or breakdown of fatty acids into acetyl-coenzyme A that primarily occurs in the mitochondrial matrix of red blood cells and tissue cells.

KETOGENESIS - refers to the synthesis or formation of ketone bodies that occurs during high rates of fatty acid oxidation where large amounts of acetyl-CoA are generated and exceed the capacity of the Kreb’s cycle.

acetoacetate, beta-hydroxybutyrate, and acetone – What are the ketone bodies?

mitochondria - Ketone bodies are produced mainly in the ______of liver cells when carbohydrates are so scarce that energy must be obtained from breaking down fatty acids.

LIPOGENESIS - refers to the synthesis of fats or triglycerides from excess carbohydrate molecules and to a smaller extent, protein. This occurs when there is high carbohydrate intake and the energy demand of the body is too low like in resting. The synthesized fat will be store in the adipose cells. Too much lipogenesis can lead to obesity.