Fats & Nuts Quiz

Fats & Nuts (with Hard Shells)

• Fats are lipids, parts of animal and plant tissues insoluble in water but dissolve in fat solvents like ether, benzene, and chloroform.
• Fats are an energy source for organisms. One gram of fat equals nine kilocalories (kcal) of energy, whereas a gram of protein or carbohydrate equals four kcal each.
• Lipids are categorized into simple lipids (e.g., fats, waxes), compound lipids (e.g., phospholipids, glycolipids, lipoproteins), and derived lipids (e.g., steroids).
• Fats are esters of fatty acids made of a glycerol molecule. 
• Glycerides are named based on the number of fatty acids they contain (e.g., monoglyceride, diglyceride, triglyceride). 
• One mole of glycerol plus one mole of fatty acid yields a monoglyceride, one mole of glycerol plus two moles of fatty acids yields a diglyceride, and one mole of glycerol plus three moles of fatty acids yields a triglyceride.
• Fats play various roles in the body, including energy storage, thermal regulation, organ protection, nerve insulation, and are essential components of cell membranes.
• Body fat percentage varies, approximately 25% for women and 15% for men.
• Fats facilitate the absorption and transport of fat-soluble vitamins (A, D, E, K) and other essential compounds for the body.
• Fats slow gastric emptying, which contributes to a feeling of satiety, and enhance the flavor and texture of food.
• Fats are broken down into fatty acids in the digestive system and absorbed.
• Short-chain fatty acids are absorbed from the small intestine and transported to the liver via the portal vein. Long-chain fatty acids are absorbed from the small intestine and transported to the liver via the lymphatic system.
• Absorbed fat is stored in adipose tissue as an energy reserve and used for energy generation.
• Fat combines with proteins to form lipoproteins, which transport fats in the bloodstream.
• Cholesterol is used to produce steroid hormones and bile acids.
• Non-essential fatty acids are synthesized as needed.
• Fats are found in visible forms (e.g., vegetable oils, butter, margarine, tallow, lard, chicken skin, and visible fat on red meat) and invisible forms (naturally present in foods like organ meats, cakes, pastries, and processed meat products). 

Fatty Acids Classified Based on Various Characteristics

• Fatty acids are categorized according to the number of carbon atoms (e.g., short-chain, medium-chain, and long-chain fatty acids), the type of bonds between carbon atoms (e.g., saturated, monounsaturated, and polyunsaturated), or their synthesis in the human body (e.g., essential and non-essential fatty acids).
• Short-chain fatty acids have less than six carbons.
• Medium-chain fatty acids have 6-10 carbons.
• Long-chain fatty acids have more than 10 carbons.
• Saturated fatty acids do not contain double bonds.
• Unsaturated fatty acids contain at least one double bond. Monounsaturated fatty acids contain a single double bond, whereas polyunsaturated fatty acids contain multiple double bonds.
• Essential fatty acids are not produced by the body and must be obtained from the diet.
• Non-essential fatty acids are produced by the body.
• Examples of fatty acids include oleic acid, linoleic acid, and alpha-linolenic acid.

Fats-Digestion and Absorption

• Fats are mechanically broken down in the mouth. 
• Some short and medium chain fatty acids are separated from triglycerides in the stomach.
• Bile mixes with fats in the duodenum, emulsifying them.
• Emulsified fats are broken down by pancreatic lipase. 
• The resulting diglycerides, monoglycerides, triglycerides, and fatty acids are absorbed into the bloodstream.

Fats-Metabolism

• Absorbed fat is stored in adipose tissue as an energy reserve.
• Fats are used for energy production.
• Fats combine with proteins to form lipoproteins for transport in the bloodstream.
• Cholesterol is used to produce steroid hormones and bile acids.
• Non-essential fatty acids are synthesized as needed.

Fats-Sources in Food

• Visible fats include liquid oils, butter, margarine, tallow, lard, chicken skin, and visible fat on red meat.
• Invisible fats are naturally present in foods such as organ meats, cakes, pastries, and processed meat products.

Properties of Fats Based on Fatty Acid Composition

• Fats high in saturated fatty acids are solid at room temperature
• Fats high in unsaturated fatty acids are liquid at room temperature
• Saturated fatty acids are typically found in animal-based foods.
• Unsaturated fatty acids are typically found in plant-based foods.
• Coconut is an exception with saturated fatty acids.

Health Risks of Saturated Fatty Acids (SFA)

• Excessive consumption can pose a risk to cardiovascular health.
• Exposure to high temperatures can produce carcinogenic substances.
• SFA is found in foods such as butter, lard, tallow, and cream.

Types of Fats

• Saturated fats (e.g. butter, hard margarine, tallow, lard, full-fat dairy products, meat) are solid at room temperature.
• Monounsaturated fats (e.g., olive oil, hazelnut oil) are liquid at room temperature.
• Polyunsaturated fats (e.g. sunflower oil, corn oil, fish oil, flaxseed, walnuts) are liquid at room temperature.

Fatty Acid Composition of Common Food Fats

• Animal-based foods and tropical oils (coconut and palm) primarily contain saturated fatty acids.
• Plant-based oils like olive and canola are rich in monounsaturated fatty acids.
• Many vegetable oils are rich in polyunsaturated fatty acids (PUFA), such as omega-3 and omega-6 fatty acids.

Dietary Fat Intake Recommendations

• Daily fat intake should be 20-35% of daily energy consumption
• Saturated fat should comprise less than 7% of the daily energy intake
• Monounsaturated fat intake should be less than 15%.
• Polyunsaturated fat intake should be less than 8-9%.
• Dietary cholesterol intake should be less than 300 milligrams daily.
• The n-6/n-3 ratio of fatty acids should be between 5:1 and 10:1.

Hard-Shelled Nuts (HSN)

• HSN are a good source of macronutrients such as fats, proteins, and carbohydrates and micronutrients such as minerals and vitamins.
• Bioactive compounds such as tocopherols, tocotrienols, phytosterols, phytostanols, terpenoids and sphingolipids and essential fatty acids.
• Phytochemicals such as phenolic acids, flavonoids, stilbenes, lignans, tannins, proanthocyanidins, carotenoids, and alkaloids are also found.
• HSN possess antioxidant and radical scavenging activity, anticarcinogenic potential, antimutagenic potential and antiproliferative potential.
• The beneficial properties contribute to their protective effects against diseases and conditions.
• Roasting raises HSN energy content.
• Fresh < Dried < Roasted HSN in energy terms.
• HSN contain phytosterols and sphingolipids.
• About half of the total fat content is unsaturated fatty acids.
• Many nuts are rich in oleic, linoleic and alpha-linolenic acids.
• Walnuts have the highest alpha-linolenic acid (ALA).
• HSN are a source of plant-based proteins with high levels of aspartic and glutamic acid, and arginine.
• HSN have low amounts of isoleucine and lysine.
• Some HSN have higher levels of methionine and cysteine, especially in almonds. -
• The level of histidine in all HSN is high.
• High lysine/arginine ratio is linked to increased risk of hypercholesterolemia and atherosclerosis.
• High levels of arginine and glycine can reduce the risk of chronic degenerative conditions.
• Low levels of CHO and fiber; almonds, pistachios, and hazelnuts have the highest fiber.
• Some key vitamins and minerals in HSN are folic acid, niacin, vitamin E, Copper and Magnesium.
• Nuts are prone to aflatoxin contamination if stored improperly, which is important to account for.
• Packaged nuts are preferred for storage.
• Shelled nuts should be preferred when buying, and loose products should be kept on closed counters.

Storage of Frying Oils

• Cool the oil in the pan until lukewarm.
• Strain the oil and store in a glass jar with a tight lid.
• Store in cool, dark, and dry environment.
• Wrap in aluminum foil if necessary.

Saponification

• Mixing oil with an alkali results in the hydrolysis of ester bonds, forming fatty acid salts.
• This process, called saponification, can be used to produce soap.
• Fatty acids with lower molecular weights lead to higher saponification numbers and bind more sodium or potassium.

Rancidity

• Oils oxidize during storage, primarily from double bonds in fatty acids. 
• The oxidation process yields hydrogen peroxide, continuing to oxidize other fatty acids.
• New molecules with varying characteristics and a rancid taste and odor develop.
• Factors affecting rancidity include higher temperatures, exposure to light, use of metal containers, and higher moisture content.
• The presence of antioxidants and the addition of sugar to baked goods help delay rancidity.

Use of Oils-Frying

• The smoke point of an oil is the lowest temperature at which volatile gases, decomposition products of the oil, are visibly released at a noticeable rate
• Selecting appropriate oils based on smoke point is critical.
• High smoke points are preferred when frying to avoid harmful compounds like acrolein.
• Frying temperature should be 160-200°C.
• Checking the temperature is done with a thermometer or by dropping a piece of bread into the oil, and waiting for it to brown within 50 seconds.
• Foods with higher moisture warrant lower frying temperatures to avoid them becoming raw inside. Foods with low moisture allow higher temperatures for better penetration.
• Changes from frying include the formation of free fatty acids, monoglycerides and diglycerides, and polymerization. Acrolein can also be formed, which is harmful. The color and taste of the oil, and the nutritional value can change, too.
• Proper storage of frying oil (in a cool, dark, and dry place with a tight lid) is important to maintain quality.