Nutrition Studies and Vitamins Quiz

Food Chemistry and Nutrition Fall 2024

• The course is about food chemistry and nutrition.
• The course is taught by Dr. Nizam Diab.
• The course is for the Fall 2024 semester.
• The course is offered at the Arab American University.

Chapter 1: Overview of Food Constituents and Their Role in Food Chemistry & Nutrition

• Definition and Importance of Food Chemistry:
  • Food is products derived from plants or animals that provide energy and nutrients for life maintenance, growth, and repair of tissues.
  • Food is essential for nutrition.
  • Diet includes all foods and beverages.
• Chemistry and Nutrition of Food Constituents: The key components of food are listed as:
  • Water
  • Carbohydrates
  • Proteins
  • Lipids (Fats)
  • Vitamins
  • Minerals
• Role of Water and Water Activity in Food:
  • Food production involves large amounts of water.
  • Water is important for food processing and transmission of diseases.
  • Water activity is affected by various chemical interactions in foods.
• The Importance of Water Activity in Foods: Water activity is a ratio of water vapor pressure in a solution to the vapor pressure of pure water.
  • Lower water activity helps to prevent microbial growth in food.
  • Chemical stability of foods is related to water activity, and is heavily influenced by it.

Introduction

• Most nutritional studies were developed in the 20th century.
• Hippocrates (400 BC) considered food as a universal nutrient.
• Antoine Lavoisier (18th century) is considered the "father of nutrition."
• The Quran and Hadith have verses related to food and nutrition.
• Modern science validates, and refutes, some aspects of traditional approaches to food.

Definition and Importance of Food Chemistry

• Food is derived from plants or animals.
• Food nourishes (supplies nutrients), sustains life, and helps maintain the body's tissues, providing energy.
• Diet refers to the food and beverages a person consumes.

What is a Nutrient?

• A nutrient is a chemical substance in food that maintains the body and supports growth, tissue repair, and disease prevention.
• Over 50 types of nutrients are needed.
• These nutrients are categorized as: Water, Lipids (fats), Vitamins, Carbohydrates, Proteins, and Minerals.

Are Nutritional and Food Chemistry the Same Thing?

• Nutritional chemistry studies food components beneficial to humans.
• Understanding individual biochemistry is the first step in addressing health problems.
• Factors like acid-alkaline balance, metabolic rate, stress levels, hormone/thyroid activity affect dietary needs.
• Food chemistry studies chemical processes and interactions within foods and how processing affects them.

Calories per Gram

• Protein: 1 gram = 4 calories
• Carbohydrates: 1 gram = 4 calories
• Fat: 1 gram = 9 calories

Variables which affect nutrient needs:

• Age
• Gender
• Activity level
• Climate
• Health
• State of nutrition

Water

• Aids digestion and cell growth and maintenance
• Facilitates chemical reactions.
• Lubricates joints and cells.
• Regulates body temperature
• Sources include liquids and food itself.

Fats

• Supply energy
• Insulate the body
• Provide essential fatty acids
• Carry fat-soluble vitamins
• Protect organs
• Types of fats include saturated, unsaturated and cholesterol

Proteins

• Builds and repairs muscles and cells
• Helps the body make important substances.
• Regulates body processes
• Supplies the body with energy.
• Types of protein (complete and incomplete).

Vitamins

• Divided into two groups: Fat-soluble and Water-soluble.
• Fat-soluble vitamins dissolve in fats and are stored in fatty tissues, including Vitamin A, Vitamin D, Vitamin E, Vitamin K.
• Water-soluble vitamins dissolve in water and are not stored in the body, including the B vitamins and Vitamin C.

Fat-Soluble Vitamins

• Vitamin A: Keeps skin and mucous membranes healthy, prevents night blindness, promotes growth
• Vitamin D: Builds strong bones and teeth
• Vitamin E: Acts as an antioxidant to protect cell membranes
• Vitamin K : Helps blood clot

Water-Soluble Vitamins

• B-Complex: Helps wounds heal, helps fight infection, helps nervous tissue functions, plays important role in the breakdown of proteins, fats, and carbohydrates.
• Vitamin C (ascorbic acid): Keeps nervous system healthy, releases energy from food, promotes healthy gums and tissues

Minerals

• This section includes elements such as Calcium, Iron, Potassium, Sodium, Iodine.
• Their functions and sources.

Food For Thought

• Avoid excesses of vitamins and minerals.
• Eat a variety of foods.
• Drink plenty of water.
• Exercise daily.
• Consult a physician or dietician before supplementing.

Role of Water and Water Activity in Food

• Food production and processing require large amounts of water.
• Water is a vehicle for disease transmission.
• Contamination of foods during production is important.
• Contaminated water contaminates food.

In Food Processing and Preservation

• Large amounts of water are needed for food processing.
• Water has a significant impact on chemical and physical changes during food processing.
• Water plays a key role in food science (boiling points, melting points, etc.).
• Water activity is the ratio of water vapor pressure in a solution to the vapor pressure of pure water.

The Importance of Water Activity in Foods

• Water activity indicates the amount of available water for microorganisms.
• Each micro-organism has a minimal water activity level below which growth is not possible.
• Controlling water activity helps in maintaining shelf-life of foods.

Chemical Stability

• Water activity plays a major role in chemical stability of food products (Maillard reaction).
• Maillard reaction becomes stronger at higher water activity values and weakens at higher water activity.
• Fats are strongly influenced with water activity.

Enzymatic Stability

• Most enzyme reactions are slowed down when water activity is below 0.8 in food.
• Heat treatment during processing minimizes enzymatic spoilage.

The Challenges and the Role of Food Chemistry

• Making healthier foods while maintaining good taste.
• Increased knowledge and improved understanding of food constituent chemistry are important to develop products with longer shelf life.
• Food chemistry can be a tool for designing and developing new food products.

Chapter 2: Major Food Constituents - Properties and Interactions

• Nutrition is essential for good health.
• A balanced diet, with several foods, is essential for health.
• Food can be classified into six main components: carbohydrates, proteins, fats, vitamins, minerals and water.

Nutrients divided into two categories:

• Macronutrients: needed in large quantities (carbohydrates, proteins, fats).
• Micronutrients: needed in lesser amounts (vitamins and minerals).

Carbohydrates

• Carbohydrates are abundant organic molecules.
• Carbohydrates are a major energy source for the body.
• Carbohydrates play several roles in food products (sweetening, thickening, forming gels, etc.).

2.1.1 Monosaccharides and their Chemical Properties

• Monosaccharides are simple sugars (glucose, fructose, mannose, galactose).
• Crystalline solids, soluble in water, and have sweet tastes.
• Classified according to placement of carbonyl group and the numbers of carbon atoms.

2.1.2 Oligosaccharides

• Oligosaccharides are composed of a few monosaccharide units (e.g., sucrose, lactose, maltose).
• Sucrose occurs in plant juices (sugar cane, sugar beet, etc.), important sweetner.

2.1.3 Polysaccharides

• Polysaccharides are complex carbohydrates made up of many monosaccharide units (e.g., starch, cellulose).

2.1.4 Properties and Functions of Starch

• Starch is a reserve carbohydrate in plants (tubers, grains, seeds).
• Starches occur in grains in various shapes (spherical, oval, lenticular).
• Starch granules swell when treated with water.
• Soluble starch fraction (amylose) and insoluble starch fraction (amylopectin) are mixtures.

2.1.5 Modified Starches and Their Application in the Food Industry

• Modified starches are made from natural starches through physical or chemical treatments.
• Modified starches improve texture, reduce cracking and increase resistance to breakage.

2.1.6 Resistant Starch

• Resistant starch is the sum of starch products in healthy individuals resisting digestion in the small intestines.

• Three types of resistant starch have been identified(RS1-3).

  • RS1: Physically trapped starch.
  • RS2: Resistant starch granules
  • RS3: Retrograded starch

2.1.7 Selection of an Optimum Starch for Snack Development

• Functional starches are great in snack development
• Selecting the best starch is challenging considering all the functional attributes of food starch.

1. Baked Snacks

• In baked products, pregelatinized starches (cold water swelling starches ) are preferred in baking for ease of processing in minimum water environments.
• Starch-based products are improved if modified forms of starch are used.

2. Fried Snacks

• Frying dehydrates products, resulting in a different texture and mouth-feel quality.
• Cross-linked or modified starches maintain the structure of fried snacks.

3. Extruded Snacks

• Moist and starchy ingredients heated under pressure result in expanding dough in a product.
• Cross linked starches increase product uniformity during extrusion.
• Amylopectin increases expansion and softness.

4. Film Forming, Sheen, Protection, and Bonding

• Starch solids can create a film to hold or bond bits, spices, or small fruit to foods.
• Starch solids increase the resistance to breakage of food products during transport.

These notes cover the various topics found in the provided pages.