Principles of Food Science

🍕Principles of Food Science Unit 2 – Food Chemistry: Macro & Micronutrients

Food chemistry explores the intricate world of macro and micronutrients. Carbohydrates, proteins, and fats provide energy and building blocks, while vitamins and minerals support essential bodily functions. Understanding these nutrients' structures, functions, and interactions is crucial for maintaining optimal health. Chemical reactions in food, like the Maillard reaction and caramelization, affect flavor and appearance. Nutrient bioavailability, influenced by food processing and interactions, impacts our bodies' ability to absorb and use essential nutrients. This knowledge is vital for developing nutritious food products and making informed dietary choices.

Key Concepts and Definitions

  • Macronutrients provide energy and essential building blocks for growth and maintenance of the body
    • Carbohydrates, proteins, and fats are the three main macronutrients
  • Micronutrients are essential nutrients required in small amounts for proper functioning of the body
    • Vitamins and minerals are the two main categories of micronutrients
  • Bioavailability refers to the proportion of a nutrient that is absorbed and utilized by the body
  • Chemical reactions in food involve changes in the structure and properties of food components
    • Maillard reaction, caramelization, and oxidation are examples of chemical reactions in food
  • Nutrient density is the amount of nutrients per calorie of food
    • Foods with high nutrient density provide substantial amounts of vitamins, minerals, and other nutrients relative to their calorie content (leafy greens, berries)
  • Recommended Dietary Allowances (RDAs) are the average daily intake levels sufficient to meet the nutrient requirements of nearly all healthy individuals
  • Dietary Reference Intakes (DRIs) are a set of reference values for nutrient intake, including RDAs, Adequate Intakes (AIs), and Tolerable Upper Intake Levels (ULs)

Macronutrients: Structure and Function

  • Carbohydrates are the primary source of energy for the body and are composed of carbon, hydrogen, and oxygen
    • Simple carbohydrates include monosaccharides (glucose, fructose) and disaccharides (sucrose, lactose)
    • Complex carbohydrates are polysaccharides, such as starch and dietary fiber
  • Proteins are essential for growth, repair, and maintenance of body tissues and are composed of amino acids
    • Essential amino acids cannot be synthesized by the body and must be obtained through diet (leucine, lysine)
    • Non-essential amino acids can be synthesized by the body
  • Fats, also known as lipids, provide energy, insulation, and protection for organs
    • Saturated fats are solid at room temperature and are mainly found in animal products (butter, lard)
    • Unsaturated fats are liquid at room temperature and are found in plant-based sources (olive oil, avocados)
      • Monounsaturated fats have one double bond in their chemical structure
      • Polyunsaturated fats have two or more double bonds in their chemical structure
  • Water is essential for many bodily functions, including nutrient transport, temperature regulation, and waste removal

Micronutrients: Types and Importance

  • Vitamins are organic compounds required in small amounts for various metabolic processes
    • Fat-soluble vitamins (A, D, E, K) are stored in the body's fatty tissues and can accumulate to toxic levels if consumed in excess
    • Water-soluble vitamins (B-complex, C) are not stored in the body and need to be consumed regularly
  • Minerals are inorganic elements that play crucial roles in many bodily functions
    • Macrominerals (calcium, phosphorus, magnesium) are required in larger amounts
    • Microminerals or trace elements (iron, zinc, iodine) are needed in smaller quantities
  • Antioxidants are compounds that protect cells from damage caused by free radicals
    • Vitamins C and E, beta-carotene, and polyphenols are examples of antioxidants
  • Phytochemicals are bioactive compounds found in plants that have potential health benefits (flavonoids, carotenoids)
  • Deficiencies in micronutrients can lead to various health problems
    • Iron deficiency can cause anemia, characterized by fatigue and weakness
    • Vitamin D deficiency can lead to rickets in children and osteomalacia in adults

Chemical Reactions in Food

  • Maillard reaction occurs between amino acids and reducing sugars, resulting in browning and flavor development (seared steak, toasted bread)
    • The reaction produces melanoidins, which contribute to the color and flavor of foods
  • Caramelization is the browning of sugars when exposed to heat, resulting in the formation of complex flavors and aromas (caramel, dulce de leche)
  • Oxidation of lipids leads to rancidity and off-flavors in foods
    • Antioxidants can help prevent or delay lipid oxidation (vitamin E, rosemary extract)
  • Enzymatic reactions can cause both desirable and undesirable changes in food
    • Ripening of fruits involves enzymatic reactions that break down cell walls and change texture
    • Enzymatic browning occurs when cut fruits and vegetables are exposed to air (sliced apples, potatoes)
  • Fermentation is a process in which microorganisms convert sugars into alcohol or acids, resulting in unique flavors and textures (yogurt, sauerkraut, beer)

Nutrient Interactions and Bioavailability

  • Nutrient interactions can affect the absorption and utilization of nutrients in the body
    • Vitamin C enhances the absorption of non-heme iron from plant-based sources
    • Calcium can interfere with the absorption of iron and zinc when consumed in large amounts
  • Bioavailability of nutrients is influenced by various factors, including the food matrix, processing, and individual differences
    • Heme iron from animal sources has higher bioavailability compared to non-heme iron from plant sources
    • Fat-soluble vitamins require the presence of dietary fat for optimal absorption
  • Antinutrients are compounds that can interfere with the absorption and utilization of nutrients
    • Phytates in whole grains and legumes can reduce the absorption of minerals like iron and zinc
    • Oxalates in spinach and other leafy greens can bind to calcium and reduce its absorption
  • Nutrient synergy occurs when the combined effect of nutrients is greater than the sum of their individual effects
    • Vitamin D and calcium work together to promote bone health
    • Vitamin C and vitamin E have a synergistic effect in protecting cells from oxidative damage

Food Processing and Nutrient Changes

  • Thermal processing, such as cooking and pasteurization, can affect the nutrient content of foods
    • Heat can destroy heat-sensitive vitamins like vitamin C and thiamin
    • Cooking can improve the digestibility and bioavailability of some nutrients (lycopene in tomatoes, beta-carotene in carrots)
  • Mechanical processing, such as milling and refining, can remove nutrient-rich parts of foods
    • Refining whole grains into white flour removes the bran and germ, which contain fiber, vitamins, and minerals
  • Fortification is the addition of nutrients to foods to prevent deficiencies or restore nutrients lost during processing
    • Iodized salt helps prevent iodine deficiency disorders
    • Vitamin D is often added to milk to promote calcium absorption and bone health
  • Fermentation can enhance the nutritional value of foods by increasing the bioavailability of nutrients and producing beneficial compounds
    • Fermented dairy products, such as yogurt and kefir, contain probiotics that support digestive health
    • Fermentation of soybeans into tempeh and miso increases the bioavailability of isoflavones and other beneficial compounds

Health Implications and Dietary Recommendations

  • Balanced nutrition is essential for maintaining optimal health and preventing chronic diseases
    • Consuming a variety of nutrient-dense foods from all food groups helps ensure adequate intake of essential nutrients
  • Dietary Guidelines for Americans provide evidence-based recommendations for healthy eating patterns
    • Emphasize the consumption of fruits, vegetables, whole grains, lean proteins, and healthy fats
    • Limit the intake of added sugars, saturated fats, and sodium
  • Chronic diseases, such as obesity, type 2 diabetes, and cardiovascular disease, are often associated with poor dietary habits
    • High intake of added sugars and saturated fats can contribute to the development of these diseases
    • Adequate intake of fiber, vitamins, and minerals can help reduce the risk of chronic diseases
  • Nutrient deficiencies can lead to specific health problems
    • Vitamin A deficiency can cause night blindness and impaired immune function
    • Folate deficiency during pregnancy can increase the risk of neural tube defects in the developing fetus

Practical Applications in Food Science

  • Food product development involves the creation of new food products with desired nutritional profiles
    • Formulating products with reduced sugar, fat, or sodium content while maintaining taste and texture
    • Incorporating functional ingredients, such as prebiotics and probiotics, to promote health benefits
  • Nutrient analysis is the process of determining the nutrient content of foods
    • Analytical techniques, such as chromatography and spectroscopy, are used to quantify nutrients
    • Nutrient databases, such as the USDA FoodData Central, provide information on the nutrient composition of various foods
  • Food labeling regulations require the disclosure of nutrient information to consumers
    • Nutrition Facts panels on packaged foods display the amount of calories, macronutrients, and selected micronutrients per serving
    • Health claims on food labels must be supported by scientific evidence and approved by regulatory agencies
  • Sensory evaluation is used to assess the acceptability and quality of food products
    • Trained panelists evaluate the appearance, aroma, taste, and texture of foods
    • Consumer testing helps determine the preferences and attitudes of target populations towards food products
  • Food safety practices aim to prevent foodborne illnesses and ensure the quality of food products
    • Implementing Hazard Analysis and Critical Control Points (HACCP) systems to identify and control potential hazards
    • Monitoring and controlling factors such as temperature, pH, and water activity to prevent microbial growth and spoilage


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© 2024 Fiveable Inc. All rights reserved.
AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.