Nutrition and Energy in Food Science

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary role of nutrients in food for the human body?

To provide colors and flavors to meals

To serve as a source of vitamins and minerals only

To enhance our cultural identity and social interactions

To supply the chemical energy for work and sustain life (correct)

What does the term 'calorimetry' refer to?

A technique for calculating metabolic rates in humans

The process of converting calories into joules

A method to measure the energy content of food (correct)

The measurement of temperature changes in environments

How many joules are equivalent to 1 calorie?

1 calorie = 1.5 joules

1 calorie = 8.5 joules

1 calorie = 2.39 joules

1 calorie = 4.2 joules (correct)

What unit is used to express the energy content of food on packages?

Calories Signup and view all the answers

If a substance has a caloric value, what does that indicate?

It can raise the temperature of 1 gram of water by 1℃. Signup and view all the answers

What is the primary role of fats in the human body?

Serves as energy storage Signup and view all the answers

Which characteristic distinguishes saturated fatty acids from unsaturated fatty acids?

Presence of carbon-carbon double bonds Signup and view all the answers

How does body stress, such as illness or pregnancy, affect energy expenditure?

It increases energy expenditure Signup and view all the answers

What is the structure of a fatty acid primarily made up of?

Long hydrocarbon chains and a carboxylic acid head Signup and view all the answers

Which of the following statements about fats is NOT true?

Fats are highly soluble in water Signup and view all the answers

What is the role of HDL in cholesterol transport?

To remove cholesterol deposits from arteries Signup and view all the answers

Which type of fatty acids are known to lower the risk of heart disease?

Mono-unsaturated fatty acids Signup and view all the answers

What process occurs when two monosaccharides form a disaccharide?

Dehydration Signup and view all the answers

Why are essential fatty acids important for human health?

They are necessary and must come from the diet. Signup and view all the answers

What is the main characteristic of trans-fatty acids?

They are produced by hydrogenation of vegetable oils. Signup and view all the answers

What is the primary factor that determines the melting point of triglycerides?

Length of fatty acid chain Signup and view all the answers

Which type of fatty acid is characterized by having one or more double bonds?

Unsaturated fatty acid Signup and view all the answers

What does a higher iodine number indicate about a triglyceride?

It has more unsaturated bonds Signup and view all the answers

How do unsaturated fatty acids differ structurally from saturated fatty acids?

They adopt a bent orientation Signup and view all the answers

Which of the following best describes the composition of fats and oils in the diet?

Complex mixtures of triglycerides with varying saturation Signup and view all the answers

Study Notes

Course Information

Course Title: The Chemistry of Life
Course Code: UGEB2380
Academic Year: 2024-2025
Instructor: Dr. Sam CK HAU (Department of Chemistry)

Energy of Food

Food is the chemical fuel providing energy for the human body
Food energy is similar to gasoline for motor vehicles

Foods and Drinks

Foods and drinks define culture and are integral parts of families and social lives
Examples of dietary components include trans fats, saturated fats, and omega-3s

Energy, Heat, and Work

Nutrients in food supply chemical energy for work and sustaining life through metabolism
Energy is the capacity to do work and is measured in terms of its heat equivalent
Calorie is a common unit for energy/heat, equal to 1000 calories or 1 kilocalorie (kcal).
Calorimetry is the technique used to measure heat.

Watts, Joules, and Calories

1 Watt = 1 Joule per second
1 Joule = 0.24 calories
1 calorie = 4.2 joules

The Human Body

Metabolism is the collection of chemical reactions in a living organism to support life
Metabolism converts food into energy and the physical substance of the body
The key chemical reaction in metabolism is C₁₂H₂₂O₁₁ + 12O₂ → 12CO₂ + 11H₂O + Energy
Metabolic processes happen more slowly than combustion, but at milder conditions

Nutrients

Macronutrients provide energy and building materials for the body
They are classified as fats and oils, carbohydrates, and proteins
Micronutrients are needed in small amounts including vitamins and minerals but do not provide energy directly

Energy In and Out

Fats and oils provide a large amount of energy (9 calories/gram)
Carbohydrates provide 4 calories/gram
Proteins provide 4 calories/gram
Alcohol provides 7 calories/gram
Energy usage is through exercise and other metabolic processes - thermic effect of food and basal metabolism
Energy storage includes body fat and glycogen

Thermic Effect of Food (TEF)

Energy used in digestion and metabolization of food
After a meal, body temperature can feel warmer, and heart rate slightly increases
The process of digestion can temporarily reduce alertness

Basal Metabolism

Energy used to sustain basic bodily functions (like heart beat, breathing and organ function)
Basal metabolic rate (BMR) is used to measure the metabolic activity at rest (12 hours fasting)
BMR is roughly 1 calorie per kg of body weight per hour
BMR can be influenced by emotions and stress like illness or pregnancy

Fats and Oils

Fats and oils serve as energy storage, insulate, and provide protective cushioning for organs.
They contain no flavor but can contain substances highly soluble in fat for flavoring.
Fats can be saturated or unsaturated
Fats and Oils are triglycerides containing glycerol and fatty acids

Fatty Acids

Fatty acids are long hydrocarbon chains with a carboxyl group
The length and number/nature of carbon-carbon double bonds affect their physical properties like melting points.
The type of fatty acid in fat or oil affects its state (solid or liquid).

Saturated & Unsaturated Fatty Acids

Saturated fatty acids have no double bonds and are usually solid at room temperature
Unsaturated fatty acids have one or more double bonds and are usually liquid at room temperature
The nature of carbon-carbon double bonds changes the fatty acid shape

Fats and Oils in Our Diet

Nature of fats and oils is often a complex mixture of triglycerides
Fats and oils can be long, short, fully saturated, monounsaturated, or polyunsaturated
Unsaturated fats are generally healthier, while overconsumption of saturated or trans fats are potentially harmful
Trans fatty acids are unintended byproducts of hydrogenation

Essential Fatty Acids (EFAs)

Important for health
Cannot be made by the body, thus must come from the diet
Omega-3 fatty acids lower risk of heart disease, and are found in salmon, fatty fishes, walnuts, and flaxseed.

Carbohydrates

Carbohydrates are a macronutrient providing energy for organisms
Primarily composed of carbon hydrogen and oxygen
Carbohydrates exist as monosaccharides, disaccharides and polysaccharides
Ratio of hydrogen to oxygen is approximately 2:1 (like water)

Types of Carbohydrates

Monosaccharides are simplest carbohydrates (e.g., glucose, fructose, galactose)
Disaccharides are two monosaccharides joined by covalent bonds (e.g., sucrose, lactose, maltose)

Carbohydrates and Diet

High glycemic index foods contain refined sugars and cause drastic changes in blood sugar levels, risking diabetes and obesity
Low glycemic index foods digest slowly and help maintain stable blood sugar levels
Enzyme sucrase breaks down complex carbohydrates (e.g., sucrose) into easily absorbable monosaccharides
Starch in plants serves as macronutrients, providing dietary fiber
Starch is digested by enzymes (which only recognize a certain bond chemical arrangement), but cellulose isn't.

Glycogen

Glycogen is storage form of glucose in animals
Stored largely in liver and muscles
Glycogen is broken down quickly for energy when needed

Lactose

Lactose is a sugar found in milk
Infants/children have lactase, which breaks down lactose to glucose and galactose
Adults typically lose lactase production capability, resulting in lactose intolerance

Proteins

Proteins are polymers of amino acids
Genes provide the blueprint for specific proteins
Proteins are needed for making muscles, hair, enzymes and other bodily components

Amino Acids

Amino acids are the building blocks of proteins.
They can be grouped into nonpolar, polar neutral, polar acidic, and polar basic based on their side chains

Structures of Proteins

Proteins have four levels of structure: primary, secondary, tertiary, and quaternary
Primary structure is the sequence of amino acids
Secondary structure includes regions of coiled structures, including Beta sheets and Alpha helix structures
Tertiary structure folds further to form a complex three-dimensional shape which can include various chemical functions or bonds
Quaternary structure involves the combination of multiple tertiary structure proteins

Fibrous and Globular Proteins

Fibrous proteins have elongated, strong structures (e.g. muscles, hair)
Globular proteins have folded, soluble shapes with diverse functions (e.g., enzymes)

Protein Denaturation

Protein denaturation is an irreversible change in the protein structure due to environmental changes (e.g., heat)
This can lead to changes in the protein's shape and function

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz explores the essential roles of nutrients and the concept of calorimetry in human health. Questions focus on the energy content of food, the role of fats, and differences between fatty acids. Test your knowledge on how nutrition impacts the body and energy expenditure in various conditions.