Food Chemistry FBTU1206

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Questions and Answers

What does food chemistry primarily study?

The nutritional values of food

The aesthetics of food presentation

The historical uses of various food ingredients

The reactions and interactions of food components (correct)

Which of the following is a minor area related to food chemistry?

Organic chemistry (correct)

Linguistics

Philosophy

Sociology

What are some conditions under which food chemistry examines changes in food?

Meteorological patterns

Cultural influences on food

Storage, processing, and cooking (correct)

Psychological effects on taste

Which concept is NOT typically associated with food chemistry?

Culinary artistry (C) Signup and view all the answers

Which of the following best describes the focus of food chemistry?

The composition and behavior of food components (A) Signup and view all the answers

Which discipline is NOT considered a minor area in food chemistry?

Botany (D) Signup and view all the answers

What is a key aspect of food chemistry when examining food components?

Chemical changes during cooking (A) Signup and view all the answers

What are the primary macronutrients found in food?

Carbohydrates and Fats (B), Water and Proteins (C) Signup and view all the answers

Which of these areas does food chemistry NOT directly overlap with?

Agricultural science (B) Signup and view all the answers

Which food has the highest water content based on the provided data?

Tomato (D) Signup and view all the answers

Which of these foods has the lowest water content?

Wheat flour (D) Signup and view all the answers

Which of the following is classified as a micronutrient?

Vitamins (C) Signup and view all the answers

What is one key function of water in foods?

Acts as a solvent (C) Signup and view all the answers

Which food item among these is most likely to be dehydrated to lower its water content?

Dried fish (D) Signup and view all the answers

What percentage of water content does dried fruits typically contain?

28% (D) Signup and view all the answers

Which of the following statements about water in food is incorrect?

Dried fish has more water than bread. (B) Signup and view all the answers

What is the molecular weight of water?

18.0153 (D) Signup and view all the answers

At 1 atm pressure, what is the boiling point of water?

100.0°C (C) Signup and view all the answers

Which phase transition has the highest energy requirement at 0°C?

Heat of sublimation (C) Signup and view all the answers

What effect do colligative properties have on the boiling point of a solvent when a solute is added?

Decreases the boiling point (A) Signup and view all the answers

What is the heat of fusion of water at 0°C?

6.012 kJ/mol (C) Signup and view all the answers

Which of these examples represents a colloid?

Milk (C) Signup and view all the answers

What happens to the vapor pressure of a solution when a solute is added?

It decreases (A) Signup and view all the answers

What is the heat of vaporization of water at 100°C?

40.657 kJ/mol (B) Signup and view all the answers

What is the critical point in the context of phase equilibrium?

The point at which liquid and gas phases are indistinguishable (C) Signup and view all the answers

During freeze drying, which process occurs as the temperature of the product decreases?

Water evaporates without passing through a liquid phase (C) Signup and view all the answers

Which of the following is a physical property of ice?

Hexagonal structure (A) Signup and view all the answers

What characterizes Type 1 water in foods?

Bound to other molecules by hydrogen bonds (D) Signup and view all the answers

At what condition does the sublimation of ice occur in freeze drying?

Under low temperature and low pressure (B) Signup and view all the answers

What is a defining characteristic of bound water in food products?

It forms hydrates with other molecules (B) Signup and view all the answers

Which statement about ice's density is correct?

It has a density less than that of liquid water (A) Signup and view all the answers

What distinguishes type 2 water from pure water?

It is trapped in microcapillaries of food. (C) Signup and view all the answers

What form does water take when it interacts with proteins, carbohydrates, and lipids?

Type 1 water, which is fully bound (B) Signup and view all the answers

Which type of water is considered to be easily removed and can participate in biological reactions?

Type 4 water (A) Signup and view all the answers

How is water activity (aw) defined in food materials?

It indicates the availability of water for chemical or biological reactions. (D) Signup and view all the answers

What is the possible value range for water activity (aw)?

0.0 to 1.0 (D) Signup and view all the answers

Which type of water acts as free water and is easily removable?

Type 3 water (B) Signup and view all the answers

Relative humidity (RH) is defined as?

The amount of water contained in the air. (B) Signup and view all the answers

What does moisture content refer to in food?

The total water weight present in food as a percentage. (A) Signup and view all the answers

Which of the following statements about type 3 water is true?

It is physically bound in matrix tissue of food. (D) Signup and view all the answers

Study Notes

Food Chemistry Overview

Food chemistry examines the composition, behavior, interactions, and reactions of food components.
Focus areas include changes occurring during production, storage, processing, preparation, and cooking.
Relevant fields include biochemistry, chemical engineering, nutritional biochemistry, organic chemistry, physical chemistry, toxicology, and analytical chemistry.

Food Composition

Major food components:
- Macronutrients: Water, carbohydrates, proteins, lipids (fats).
- Micronutrients: Vitamins and minerals.

Role of Water in Food

Water content varies significantly across different foods:
- High water content: Tomato (94%), Watermelon (93%), Cabbage (92%).
- Lower water content: Dried fish (38%), Bread (36%), Dried fruits (28%).
Bovine milk contains 90% water, while milk powder has 14%.

Physicochemical Properties of Water

Molecular weight of water is 18.0153.
Melting point: 0.0°C; Boiling point: 100°C.
Heat of fusion at 0°C is 6.012 kJ (1.436 kcal)/mol.
Heat of vaporization at 100°C is 40.657 kJ (9.711 kcal)/mol.

Water Behavior in Food

Colligative properties demonstrate how solute interactions affect water properties, lowering vapor pressure, freezing point, boiling point, and osmotic pressure.

Dispersion Systems in Food

Solutions involve solutes like salt or sugar in water.
Suspensions include flour in water.
Colloids are exemplified by milk.

Types of Water in Foods

Type 1: Real bound water, forming hydrates, cannot freeze.
Type 2: Monolayer water, trapped in microcapillaries.
Type 3: Physically bound water, facilitates biological & chemical reactions, reflects food humidity levels.
Type 4: Free/mobilized water, easily removed, available for reactions.

Moisture Content & Water Activity

Moisture content refers to the amount of water in food, expressed as a percentage.
Relative humidity (RH) defines water vapor present in the air.
Water activity (aw) measures the availability of water for reactions, ranging from 0 (no activity) to 1 (pure water).

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Description

This quiz covers the essential concepts of food chemistry as outlined in the course FBTU1206. You will explore the chemical properties and structures that influence food quality and safety. Perfect for students seeking a deeper understanding of the chemical processes in food.