Since the beginning of humanity, the pursuit of sustenance has been a fundamental endeavor. Food holds profound significance in our daily lives, serving as the essential source of nourishment for the body.
Defined as any substance that, upon consumption, digestion, and absorption, generates energy, fosters growth, repairs tissues, and regulates bodily processes, food owes its functional attributes to the presence of chemicals known as nutrients.
The scientific exploration of these nutrients and their impact on the human body constitutes the field of nutrition. Nutrition is, therefore, the study of the relationship between food and health.
The significance of human nutrition
Essential for Human Existence: Food is a crucial aspect of human life.
Intellectual Development: A strong connection exists between quality food and intellectual development.
Maintenance of Good Health: It contributes to the upkeep of overall health.
Understanding Food Principles: Knowledge of food processing, preservation, and preparation is vital.
Disease Resistance: Well-nourished individuals exhibit greater resistance to diseases.
Dietary Requirements: Understanding the dietary needs of diverse age groups and those in psychological conditions.
Impact of Food Proportions: The proportion of consumed food can have positive or negative effects on the body.
Basic Knowledge of Nutrition: It aids in comprehending the fundamental principles of nutrition.
Factors influencing human nutrition
Availability of Food: The accessibility of food resources.
Seasonal Availability: The presence of food in different seasons.
Ignorance: Lack of awareness affecting food choices.
Storage/Preservation: Methods employed for storing and preserving food.
Facilities: The availability of facilities for food-related activities.
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Career Opportunities available in Food and Nutrition
The field of foods and nutrition presents a diverse array of career opportunities, each offering a unique pathway for individuals with a passion for promoting health and well-being. These opportunities span various sectors, including education, healthcare, hospitality, and research. Here is an expanded overview of the career options available in foods and nutrition:
Teaching:
Educators in foods and nutrition play a crucial role in shaping the next generation of professionals. They may work in schools, colleges, or universities, imparting knowledge on nutrition, food science, and related subjects.
Dietetics:
Dietitians work with individuals to assess their nutritional needs and develop personalized plans to improve their health. They can be found in hospitals, clinics, private practices, or even as consultants to athletes and sports teams.
Hospitality and Tourism:
Professionals in this sector focus on ensuring that the food and nutrition aspects of hotels, restaurants, and tourism establishments meet high standards. This includes menu planning, quality control, and catering services.
Food Science:
Food scientists study the physical, chemical, and biological properties of food to enhance safety, quality, and nutritional value. They may work in research and development for food companies or government agencies.
Food Science and Technology:
This field involves applying scientific principles to the production and processing of food. Food technologists work on developing new food products, improving food safety, and finding innovative methods for food preservation.
Food Engineering:
Food engineers focus on designing and optimizing processes and equipment used in food production. They play a vital role in ensuring efficiency, sustainability, and safety in the manufacturing of food products.
Hotel and Catering Management:
Professionals in this field manage the overall operations of hotels, catering services, and related businesses. They are responsible for ensuring high-quality food services and customer satisfaction.
Food Research and Development:
Researchers in this area work on discovering new ingredients, improving existing products, and developing innovative solutions to address nutritional challenges. This often involves collaboration with food companies or research institutions.
Community Nutrition:
Community nutritionists focus on promoting health and nutrition within communities. They may work with public health agencies, non-profit organizations, or community centers to implement nutrition education and outreach programs.
Institutional Matron:
This role involves overseeing the nutritional well-being of individuals in institutions such as schools, hospitals, or care facilities. Institutional matrons ensure that proper dietary guidelines are followed for the health of the residents.
Clinical Nutrition:
Clinical nutritionists work in healthcare settings, collaborating with healthcare professionals to provide specialized nutrition care for patients with medical conditions. They assess nutritional needs and develop therapeutic diet plans.
Nutrition in Media:
Professionals in this field use various media platforms to disseminate accurate and accessible information about nutrition. This may include writing articles, hosting podcasts, creating videos, or contributing to social media to educate the public on healthy eating habits.
These diverse career paths within foods and nutrition cater to a wide range of interests and expertise, allowing individuals to make meaningful contributions to the health and well-being of individuals and communities.
Relationship between food and nutrition to other subjects.
Food and nutrition do not exist as standalone disciplines; instead, they constitute a field of study that intersects with various other academic domains and holds a crucial role in the ongoing survival of the human population.
The interdependence of food and nutrition with agriculture is undeniable. Their connection is so profound that they both fall under the umbrella of a single global organization: the Food and Agriculture Organization (FAO), headquartered in Rome.
The sustenance of human life heavily relies on the cultivation of both plants and animals. While humans derive their primary food sources from plants and animals, the latter are entirely dependent on their sources of sustenance. Consequently, to ensure an ample food supply for human consumption, a comprehensive approach to agriculture, encompassing both crops and livestock, must be earnestly embraced and widely practised.
This interdisciplinary field involves the following related subjects:
Agricultural Science:
Agricultural science delves into the study of farming techniques, crop cultivation, soil management, and sustainable agricultural practices. It aims to enhance the efficiency and productivity of agricultural processes, ensuring a stable and abundant food supply.
Biology:
Within the context of food and nutrition, biology explores the intricate biological processes governing living organisms’ growth, development, and metabolism. Understanding biological principles is crucial for comprehending the nutritional requirements and benefits associated with various food sources.
Chemistry:
In the realm of food and nutrition, chemistry plays a vital role in elucidating the composition of nutrients, food additives, and reactions occurring during food processing. Analyzing the chemical aspects of food helps in ensuring its safety, quality, and nutritional value.
Physiology:
Physiology investigates the functions and mechanisms of the human body, providing insights into how nutrients are absorbed, utilized, and metabolized. This knowledge is fundamental in tailoring dietary recommendations to meet the specific physiological needs of individuals.
Food Technology:
Food technology focuses on the application of scientific and engineering principles to enhance food production, preservation, and processing. It plays a pivotal role in developing innovative methods to ensure food safety, extend shelf life, and improve overall food quality.
Home Economics:
Home economics encompasses the practical aspects of managing a household, including meal planning, budgeting, and nutrition. It empowers individuals with the skills to make informed choices regarding food selection, preparation, and overall well-being.
Food Science:
Food science explores the physical, chemical, and biological properties of food, aiming to understand how these factors influence its taste, texture, and nutritional value. This interdisciplinary field contributes to the development of new food products and improved methods of food preservation.
Food Engineering:
Food engineering integrates engineering principles with food science to optimize food processing, packaging, and distribution. It involves designing efficient systems and technologies to ensure the safe and sustainable production of a diverse range of food products.
Microbiology:
Microbiology investigates the role of microorganisms in food production, preservation, and safety. Understanding microbial interactions is crucial for preventing foodborne illnesses and ensuring the microbiological quality of food.
Medicine:
In the context of food and nutrition, medicine explores the relationship between dietary habits and health outcomes. Nutritional medicine emphasizes the role of proper nutrition in preventing and managing various health conditions.
Economics:
Economic principles are essential in understanding the dynamics of food production, distribution, and consumption. The study of food economics addresses issues such as resource allocation, market dynamics, and food policy, influencing global and local food systems.
Physics:
Physics in the context of food and nutrition involves understanding the physical properties of food, such as heat transfer during cooking and preservation methods based on physical principles. This knowledge contributes to optimizing food processing and ensuring its safety.
Physical and Health Education:
Physical and health education emphasizes the importance of maintaining an active and healthy lifestyle. Within the context of food and nutrition, it educates individuals on the relationship between diet, physical activity, and overall well-being.
Basic Food Nutrients (Carbohydrates)
Nutrients needed in significant quantities by the body are known as macronutrients, while those required in smaller amounts are termed micronutrients. Each of these nutrients has specific functions, and their deficiency in the diet can lead to various health issues.
Carbohydrates:
Carbohydrates consist of carbon, hydrogen, and oxygen and are primarily synthesized by plants through photosynthesis. Animals acquire carbohydrates by consuming plants that undergo carbohydrate synthesis. Carbohydrates are categorized into three types:
Monosaccharides:
These are the smallest carbohydrate units, known as simple sugars, such as glucose, fructose, and lactose.
Oligosaccharides:
Comprising 2 to 10 monosaccharide units, oligosaccharides include substances like maltose, lactose, and sucrose.
Polysaccharides:
Made up of more than ten monosaccharide units, polysaccharides include compounds like starch, cellulose, and pectin.
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20 Functions of Carbohydrates:
Carbohydrates play several essential roles in the body:
Energy Source: Carbohydrates are the primary source of energy for the body, providing fuel for cellular processes, organ function, and physical activities.
Glucose Regulation: Carbohydrates help regulate blood glucose levels, preventing hypoglycemia (low blood sugar) and hyperglycemia (high blood sugar).
Glycogen Storage: Excess glucose is stored in the liver and muscles as glycogen, which can be broken down when energy is needed.
Cellular Structure: Carbohydrates play a structural role in cells, forming components such as cell membranes and cell walls (e.g., cellulose in plant cell walls).
Nucleic Acid Synthesis: Carbohydrates are essential for the synthesis of nucleic acids (DNA and RNA), providing the backbone for these molecules.
Energy Storage: Plants store energy in the form of carbohydrates, such as starch in seeds, tubers, and fruits.
Metabolic Intermediates: Carbohydrates serve as intermediates in various metabolic pathways, including glycolysis, gluconeogenesis, and the pentose phosphate pathway.
Protein Modification: Carbohydrates can be attached to proteins in a process called glycosylation, which can affect protein structure, stability, and function.
Cell Communication: Carbohydrates on the surface of cells play a role in cell recognition, adhesion, and communication, facilitating processes like immune response and cell signaling.
Digestive Health: Dietary fibers, a type of carbohydrate, aid in digestion by promoting bowel regularity, preventing constipation, and supporting a healthy gut microbiota.
Weight Management: High-fiber carbohydrates can contribute to satiety and weight management by promoting feelings of fullness and reducing calorie intake.
Brain Function: Glucose, derived from carbohydrates, is the primary fuel for the brain, supporting cognitive function, concentration, and mental alertness.
Fat Metabolism: Carbohydrates spare protein from being used as an energy source, allowing it to be utilized for other functions such as muscle building and repair, rather than energy production.
Thermoregulation: Carbohydrates contribute to thermoregulation by providing energy for heat production through metabolic processes.
Electrolyte Balance: Carbohydrates help maintain electrolyte balance by facilitating the absorption of sodium and potassium ions in the intestines.
Immune Function: Some carbohydrates, such as beta-glucans, have immunomodulatory effects, enhancing immune function and aiding in defense against pathogens.
Antioxidant Activity: Certain carbohydrates, particularly polysaccharides found in fruits and vegetables, exhibit antioxidant properties, scavenging free radicals and reducing oxidative stress.
Wound Healing: Carbohydrates play a role in wound healing by providing energy for tissue repair and supporting immune function at the site of injury.
Regulation of Gene Expression: Carbohydrates can influence gene expression through epigenetic mechanisms, affecting processes like cell differentiation and development.
Hormone Regulation: Carbohydrates can influence hormone levels and signaling pathways, impacting metabolism, appetite regulation, and other physiological processes.
Food Sources of Carbohydrates:
Carbohydrates, often referred to as the body’s primary source of energy, are abundant in various foods, offering a diverse array of options to meet dietary needs. Here are some common and nutrient-rich sources of carbohydrates:
Yams: With their sweet and starchy flesh, yams are a delicious and nutritious source of complex carbohydrates, providing sustained energy and essential nutrients like fiber, vitamin C, and potassium.
Rice: A staple food for a significant portion of the world’s population, rice comes in numerous varieties such as white, brown, jasmine, and basmati, all of which offer a substantial carbohydrate content along with essential minerals like manganese and selenium.
Bread: Whether it’s whole wheat, multigrain, or sourdough, bread is a versatile carbohydrate source that can be enjoyed in various forms, providing energy and dietary fiber to support digestive health.
Cassava: Commonly consumed in tropical regions, cassava is a root vegetable rich in carbohydrates, particularly in the form of starch, making it a valuable energy source for many cultures worldwide.
Maize (Corn): A versatile grain used in countless culinary applications, maize is packed with carbohydrates, fiber, and various vitamins and minerals, contributing to its status as a dietary staple in many cuisines.
Cocoyam (Taro): With its starchy tuberous roots, cocoyam serves as a nutrient-dense carbohydrate source, offering an excellent combination of energy, fiber, and essential nutrients like vitamin E and potassium.
Millet: Often cultivated in arid regions, millet is a gluten-free grain rich in complex carbohydrates, protein, and dietary fiber, making it a nutritious option for individuals with dietary restrictions or preferences.
Oats: Renowned for their heart-healthy properties, oats are a whole grain powerhouse, brimming with carbohydrates, soluble fiber, and various vitamins and minerals, making them a popular choice for breakfast cereals, porridge, and baked goods.
Barley: Another nutritious whole grain, barley boasts a hearty dose of carbohydrates, fiber, and important nutrients like selenium and manganese, offering both sustenance and culinary versatility in soups, stews, and salads.
Rye: Known for its robust flavor and dense texture, rye is a cereal grain rich in carbohydrates, fiber, and essential minerals like magnesium and phosphorus, contributing to its role in traditional bread-making and culinary exploration.
Wheat: As one of the most widely consumed grains globally, wheat provides a significant portion of the world’s carbohydrate intake, delivering energy, fiber, and essential nutrients in products ranging from bread and pasta to couscous and bulgur.
Sugarcane: Beyond its use in sweetening foods and beverages, sugarcane is a natural source of carbohydrates, offering a quick energy boost along with small amounts of fiber and essential nutrients like vitamin C and calcium.
Sorghum: A drought-tolerant grain with ancient origins, sorghum is rich in complex carbohydrates, fiber, and antioxidants, making it a valuable component of gluten-free diets and traditional cuisines around the world.
Guinea Corn (Sorghum): Widely cultivated in Africa, guinea corn, also known as sorghum, is a nutritious grain prized for its carbohydrate content, dietary fiber, and micronutrients like iron and phosphorus, serving as a dietary staple in various African dishes.
Plantains: Similar in appearance to bananas but with a starchier texture, plantains are a versatile carbohydrate source, offering energy, fiber, and essential nutrients like potassium and vitamin C, and featuring prominently in savory and sweet dishes across many cultures.
These diverse food sources provide ample carbohydrates along with essential nutrients, contributing to balanced and nutritious diets worldwide.
Proteins
Introduction to Proteins:
Protein is an essential macronutrient crucial for the body’s proper functioning. Composed of carbon, hydrogen, nitrogen, and oxygen, its fundamental building block is the amino acid. Proteins are broadly categorized into two classes, each with distinct characteristics. The first class comprises proteins containing all essential amino acids, referred to as first class, complete, or animal proteins. Conversely, the second class, known as second class, incomplete, or plant proteins, lacks one or more essential amino acids.
Functions of Proteins:
Proteins play diverse and vital roles in the body’s biological processes:
Promoting Growth: Proteins contribute to the growth and development of tissues and organs.
Tissue Repair: They play a crucial role in repairing worn-out tissues, ensuring the body’s maintenance.
Energy Source: In the absence of carbohydrates and fats, proteins serve as an alternative source of energy.
Immune System Support: Proteins aid in building antibodies that defend against infections and diseases.
Enzyme Formation: They are essential for the synthesis of enzymes, which catalyze various chemical reactions in the body.
Hormone Production: Proteins are involved in the production of hormones that regulate key bodily processes.
Structural Component: They form the major structural component of cells, providing integrity and support.
Genetic Transmission: Proteins are responsible for transmitting hereditary traits or characteristics from parents to offspring.
Deficiency and its Consequences:
Insufficient protein intake can have severe consequences:
Poor Growth: Protein deficiency leads to stunted growth and developmental issues.
Lower Resistance: The body becomes more susceptible to infections and diseases.
Infant Conditions: In infants, protein deficiency manifests as kwashiorkor and marasmus, both of which hinder proper growth and development.
Food Sources of Proteins:
Proteins can be sourced from various animal and plant-based products, including:
Animal Sources: Eggs, beans, groundnuts, milk, cheese, fish, poultry, meat, and peas are rich in proteins.
Plant Sources: Soybeans also provide a valuable plant-based protein source.
By incorporating a diverse range of protein-rich foods, individuals can ensure the body receives the necessary amino acids for optimal health and functioning.
Fats And Oils
Fats and oils are essential macronutrients required by the body, composed of carbon, oxygen, and hydrogen. When the body has an excess of carbohydrates and proteins, they can be converted into fats and stored beneath the skin. The structural components of fats and oils are glycerol and fatty acids.
Distinguishing between fats and oils reveals notable disparities:
Fats:
Solid at room temperature.
Contain saturated fatty acids.
Obtained from animals.
Oils:
Liquid at room temperature.
Contain unsaturated fatty acids.
Obtained from plants and vegetables.
The functions of fats and oils encompass a range of vital roles:
They serve as a source of heat and energy.
Acting as insulators, they prevent heat loss from the body.
Their cushioning effect protects delicate internal organs from shock and damage.
Contributing to the flavor and palatability of food, they enhance the overall eating experience.
Providing a sense of satiety, they delay the onset of hunger due to their slower digestion.
Facilitating the absorption of fat-soluble vitamins.
Promoting the health of hair and skin.
While a significant amount of fats and oils is necessary for bodily functions, excessive consumption can lead to overweight or obesity.
Various food sources rich in fats and oils include margarine, butter, and edible oils such as palm oil, groundnut oil, corn oil, soybean oil, and vegetable oil.
Vitamins
Vitamins are essential organic compounds needed by the body in small quantities. They can be categorized into two main groups:
Water-soluble vitamins: These vitamins dissolve in water and include the B complex (B1, B2, B6, B12, B15, folic acid, niacin, biotin, pantothenic acid) and vitamin C (ascorbic acid).
Fat-soluble vitamins: These vitamins can dissolve in fat and oil, including A, D, E, and K (ADEK).
Some vitamins can be synthesized from other substances, known as pro-vitamins, while certain substances can interfere with vitamin utilization and are called anti-vitamins.
Now, let’s look at specific vitamins:
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Vitamin B1 (Thiamine):
Functions: Promotes growth, increases appetite, and is involved in energy release.
Prevents beriberi.
Food sources: Whole cereals, nuts, legumes, pork, offal, etc.
Vitamin B2 (Riboflavin):
Functions: Involved in energy release, assists in red blood cell formulation, and promotes growth.
Mineral elements play a crucial role in the body, despite being required in trace amounts. These inorganic substances contribute to various functions such as growth and vital metabolic activities, and they are broadly categorized into two groups: macro elements (or trace elements) and micro elements.
Macro Elements:
Calcium (Ca): Supports the development of strong and healthy teeth, controls cell activities, aids blood clotting, facilitates the transmission of nerve signals, and ensures normal muscle function. Food sources include milk, hard water, seafood, green vegetables, and fruits.
Magnesium (Mg): Contributes to bone development, regulates muscle contraction, and is essential for nerve transmission. Food sources include hard water, seafood, and nuts.
Phosphorus (P): Essential for bone development, maintenance of acid-base balance in body fluids, energy storage and release, and cell reproduction. Food sources include green vegetables, egg yolks, seafood, liver, cereals, meat, pulses, and lime.
Sodium (Na): Maintains cell integrity and aids in the secretion of hydrochloric acid in the stomach. Food sources include table salt, meat, milk, cheese, eggs, seafood, green vegetables, and poultry.
Sulphur (S): Essential for hair and nail development and the formation of connective tissues. Food sources include cabbage, meat, fish, eggs, and nuts.
Potassium (K): Maintains cell membrane permeability, is involved in electrolyte balance, and contributes to nervous irritability and muscle contraction. Food sources include meat, potatoes, bananas, peanuts, carrots, oranges, grapefruit, and butter.
Micro Elements:
Iron (Fe): Essential for the formation of hemoglobin in red blood cells. Food sources include meat, liver, kidneys, green vegetables, legumes, and whole cereals.
Fluorine (F): Important for the development of strong bones and healthy teeth, and helps prevent dental decay. Food sources include fluoridated drinking water and toothpaste.
Water:
Water, comprising hydrogen and oxygen (H2O), is vital for human existence. Despite lacking energy value, water constitutes about two-thirds of the total body composition. It is neutral, colorless, odorless, and tasteless, serving various functions in the body:
Acts as a medium for transporting substances within the body.
Regulates body temperature.
Quenches thirst.
Assists in waste product excretion, such as urea through urine.
Aids digestion and nutrient absorption.
Maintains the moisture of organ lining membranes, acting as a lubricant.
Sources of water include drinking water, beverages, beer, and certain foods consumed.
Dietary Deficiency
Inadequate or imbalanced nutrient intake can lead to various diseases, collectively known as malnutrition. Malnutrition occurs when there is an excess or deficiency of specific nutrients, resulting in a health imbalance. There are two main types of malnutrition:
Undernutrition: This condition arises from insufficient food intake or poor nutrient utilization. It can lead to stunted growth and development.
Overnutrition: This occurs when there is an excessive intake of one or more nutrients, negatively affecting the body’s proper functioning.
Two specific types of malnutrition are Kwashiorkor and Marasmus:
Kwashiorkor is common in children and is primarily caused by a lack of protein in the diet. Symptoms include an enlarged stomach, changes in hair color and texture, swollen legs, scaly skin, and retardation of growth. Treatment involves increasing protein intake in the child’s diet.
Marasmus is a protein-calorie deficiency disease characterized by stunted growth, a skeletal appearance, saggy body tissue, and overall wasting away. Treatment includes incorporating high-protein foods, especially animal proteins, gradually adjusting the calorie intake according to the child’s age.
Anemia is another consequence of malnutrition, specifically due to an inadequate intake of iron. Common symptoms include weakness, fainting, and paleness of the skin. Treatment involves including iron-rich foods such as liver, eggs, and spinach in the diet.
Apart from these, here are five other dietary deficiencies, along with their symptoms and treatments:
Vitamin D Deficiency:
Symptoms: Bone pain, muscle weakness, fatigue.
Treatment: Increase intake of vitamin D-rich foods like fatty fish, fortified dairy products, and exposure to sunlight.
Vitamin C Deficiency (Scurvy):
Symptoms: Fatigue, swollen and bleeding gums, joint pain.
Treatment: Consume citrus fruits, strawberries, and vegetables rich in vitamin C.
Treatment: Include dairy products, leafy greens, and fortified foods in the diet.
Iodine Deficiency (Goiter):
Symptoms: Swelling of the thyroid gland, fatigue, weight gain.
Treatment: Consume iodized salt, seafood, and dairy products.
Vitamin A Deficiency (Night Blindness):
Symptoms: Difficulty seeing in low light, dry eyes.
Treatment: Eat foods rich in vitamin A, such as carrots, sweet potatoes, and leafy greens.
The Digestive System
Before food can be assimilated into the bloodstream, it undergoes a necessary transformation when taken into the mouth.
Digestion is the intricate process whereby food molecules are chemically broken down by numerous enzymes into smaller substances. These smaller components can then be absorbed into the bloodstream and assimilated into cells for utilization.
The entire digestion process occurs in the alimentary canal, comprising four major sections: the mouth, stomach, duodenum, and small intestine.
In the mouth, food is mixed and softened by saliva, which contains enzymes. The teeth masticate and crush the food into smaller particles. Saliva, containing mucin, lubricates the food, facilitates swallowing, and provides an alkaline medium essential for the action of ptyalin, an enzyme.
The stomach contains gastric juice, acidic due to hydrochloric acid (HCL). Hydrochloric acid serves three primary functions: halting the action of ptyalin from the mouth, providing the acidic medium required for rennin and pepsin activity in the stomach, and destroying any accompanying bacteria from the mouth.
From the stomach, digested products pass into the duodenum. Pancreatic juice, secreted from the pancreas, and bile from the liver, emptied into the duodenum through the bile duct, play crucial roles. Bile, lacking enzymes, emulsifies fats or oils in the chyme.
Pancreatic juice contains enzymes for carbohydrate, protein, and fat splitting:
Amylase converts starch to maltose.
Trypsin converts protein to peptides and peptones.
Lipase converts fats to fatty acids and glycerol.
Absorption
Absorption is the process through which the end products of digestion traverse the lining of the digestive tract. This occurs primarily in the inner lining of the small intestine, known as villi. Simple sugars and amino acids enter the bloodstream directly, while fatty acids enter indirectly through the lymphatic system.
Digestive processes involve various sites, each with specific functions and enzymes:
Mouth:
Digestive Juice: Saliva
Optimum pH: Alkaline
Enzyme: Ptyalin
Functions: Starch to maltose conversion
Stomach:
Digestive Juice: Gastric juice (acidic due to hydrochloric acid)
Enzymes: Pepsin, Renin
Functions: Conversion of protein to peptides and peptones; curdling of milk proteins by converting soluble caseinogen to insoluble casein
Duodenum:
Bile secreted by the gallbladder
Pancreatic juice produced by the pancreas
Optimum pH: Alkaline
Enzymes: Bile salts, amylase, trypsin, lipase
Functions: Emulsification of fats; starch to maltose conversion; protein to peptides/peptones conversion; fats to fatty acids and glycerol conversion
Functions: Various enzymatic actions on carbohydrates, proteins, and fats.
The scientific study of food
Measurement Units
Food’s energy value can be quantified in calories or joules, with kilocalories being a common larger unit of energy. The international unit for energy is the “joule.” Kilocalories represent the heat required to raise the temperature of a thousand grams (1000) of water by 1 degree Celsius. For instance, one gram (gm.) of carbohydrates yields four kilocalories, one gram of protein yields four kilocalories, and one gram of fat yields nine kilocalories.
Food Weight: Raw or processed food weight can be expressed in grams or kilograms.
1 kilogram = 1000 grams.
Macronutrients are measured in grams, while vitamins and trace elements, needed in smaller quantities by the body and present in food in small amounts, are measured in milligrams (mg.) and micrograms (μg.).
1g = 1000mg (10^3mg)
1gm = 1,000,000g (10^6g)
Or
1mg = 0.001 or 10^-3g
1g = 0.000001g or 10^-6g
Other commonly used units for measuring vitamins are the international unit (I.U) and standard unit (S.I).
Effects of Heat on Nutrients
Effects of Heat on Carbohydrates:
Carbohydrates undergo dextrinization, breaking down into simpler units for easier digestion.
In moist heat, carbohydrates gelatinize, expanding and bursting, making them more digestible.
Carbohydrates caramelize, turning brownish, usually with dry heat.
Effects of Heat on Proteins:
Heat denatures proteins, altering their primary structure and state, as seen in eggs and beans.
Proteins contract, causing food to shrink, as in meat.
Overcooking proteins results in toughness and indigestibility, as with fried fish.
Effects of Heat on Fats and Oils:
Fats change from a solid to a liquid state when heated.
Oil produces a blue haze at its smoke point (2000-2100°F), indicating potential combustion.
Heating oil beyond the smoke point leads to decomposition, producing a poisonous substance.
Food Tests: Identification Of Food Nutrients
Identifying Food Nutrients
Carbohydrates
Iodine Test: Cut a section of carbohydrate-rich food to expose the flesh. Pour drops of iodine on the exposed flesh. If it turns black or darkish brown, it indicates the presence of carbohydrates. If it remains light brown, carbohydrates are absent.
Litmus Test: Peel and grate the food item, then make it into a paste. Immerse red litmus paper into the paste. If it turns blue, it shows the presence of carbohydrates; if unchanged, it lacks carbohydrates.
Proteins
Foam Test: Dissolve the food substance in water and shake vigorously. The production of foam indicates the presence of protein. The absence of foam suggests no protein.
Alcohol Test: Immerse the food product or its solution in alcohol. Coagulation, shrinking, or curdling indicates the presence of protein. Meat may change colour to brown.
Million’s Test: Warm the foodstuff with Million’s reagent. A white precipitate, turning red, confirms the presence of protein, except for gelatin.
Fats
Blotting Paper Test: Grind a small quantity of foodstuff between two pieces of blotting or filter paper. Translucency or greasiness on the paper indicates the presence of fats or oil. Absence of such indicates no fat.
Food Composition Table
A food composition table is a tabular representation of the nutritive value (nutrient amounts) of common food commodities, whether raw, processed, or cooked.
Purposes of a food composition table:
Provides accurate information on the nutritive values of major food commodities, preventing consumer misinformation by food processors and marketers.
Facilitates the comparison of food values to help consumers make informed choices according to their nutritional needs.
Assists in meal planning tailored to specific groups, such as infants, adolescents, and the elderly.
Enables the calculation of nutritional content for comparison with standards, determining if a food meets the Recommended Daily Allowance (RDA) for nutrients.
Factors affecting the food composition table:
Nature and type of soil used to grow the commodity.
Variety of plant or breed of animal.
Age of the animal affecting meat and milk composition.
Type of feed given to animal and poultry livestock impacting meat, milk, and egg composition.
Climatic conditions during plant growth.
Handling and storage methods.
Reproductive Health
What is Reproductive Health?
Reproductive health encompasses the holistic well-being and operation of the reproductive system, encompassing both physical and mental aspects. It involves the ability to maintain a satisfying and secure sexual life, the capacity for reproduction, and the autonomy to make decisions about reproduction, including access to information and services related to sexual and reproductive health.
This comprehensive concept includes various dimensions:
Sexual Health: This entails the physical, emotional, and social aspects of sexuality, fostering a positive and respectful approach free from coercion, discrimination, and violence. It also involves access to information and services for sexual and reproductive health, as well as the prevention and treatment of sexually transmitted infections (STIs).
Family Planning: Empowering individuals and couples to decide when, whether, and how many children to have. Family planning methods and services facilitate informed choices regarding contraception and reproductive options, promoting responsible parenthood and pregnancy spacing.
Maternal Health: Focusing on women’s well-being during pregnancy, childbirth, and the postpartum period. It includes access to prenatal care, skilled attendance at delivery, and postnatal care to ensure safe motherhood and reduce maternal mortality and morbidity.
Safe Abortion: Recognizing the importance of safe and legal abortion services for women’s health. Access to safe abortion and post-abortion care helps prevent complications and maternal mortality associated with unsafe practices.
Prevention and Treatment of Infertility: Addressing challenges faced by individuals and couples experiencing difficulties conceiving. This involves access to services for diagnosis, treatment, and support related to infertility, including assisted reproductive technologies when needed.
Prevention and Management of Reproductive Tract Infections: Encompassing the prevention, diagnosis, and treatment of infections affecting reproductive organs, including sexually transmitted infections.
Prevention and Management of Reproductive Cancers: Emphasizing early detection, prevention, and treatment of cancers affecting reproductive organs such as cervical, ovarian, and breast cancer.
Promoting reproductive health requires a comprehensive approach considering physical, social, cultural, and economic factors. It involves ensuring access to quality healthcare services, education, information, and resources for informed decision-making while respecting individual rights and choices.
Reproductive Health: Relationship Between Reproductive Health and Nutrition
Reproductive health is a state of complete physical, mental, and social well-being, involving all reproductive processes, functions, and systems throughout life. Nutrition, on the other hand, encompasses the processes of ingesting, digesting, absorbing, and assimilating food substances for the growth, repair, and maintenance of the body.
Balanced nutrition is crucial for both men and women in maintaining reproductive health. Optimal nutrition includes maintaining a healthy weight, as being over or underweight can impact hormonal levels in women. A balanced diet rich in vegetables, fruits, and healthy fats, while low in saturated and trans fats and unhealthy carbohydrates, promotes reproductive health. Prenatal vitamins play a vital role in providing essential nutrients, improving a woman’s chances of conception, and ensuring proper embryo development early in pregnancy.
For prospective fathers, adopting a healthy eating regimen contributes to increased chances of success.
Malnutrition
Malnutrition refers to nutrient intake imbalance, with two sides:
Undernutrition: Resulting from inadequate food intake or poor nutrient utilization.
Overnutrition: Arising from excessive consumption of one or more nutrients, negatively impacting proper bodily functions.
Kitchen Management
A kitchen can be described as a domestic workshop in the home where all the preparation, cooking, and serving of food is done. There are two types of kitchens: 1. Family kitchen. 2. Industrial kitchen.
Family kitchen: A family kitchen can be traditional or modern. The industrial kitchen is the type of kitchen found in hotels, universities, colleges, and hospitals. This type of kitchen is often larger than the family kitchen, and the facilities needed or used are mainly mechanical and electrical. Also, this type of kitchen is more equipped than the family kitchen.
The size of the kitchen depends solely on:
Size of the building.
Family size.
The financial or economic status of the family.
The equipment to be used.
Differences Between Traditional Kitchen And Modern Kitchen
Distinguishing between traditional and modern kitchens involves considering several key aspects of their design and functionality.
Traditional Kitchen:
Location: Traditional kitchens are typically detached from the main building, creating a separate space for culinary activities.
Ventilation: These kitchens tend to be poorly ventilated due to the presence of small windows, which may hinder the proper circulation of air.
Floor Material: The floor of a traditional kitchen is often made of mud, giving it a rustic and traditional feel.
Fuel Sources: Traditional kitchens rely on traditional sources of fuel such as charcoal, firewood, or sawdust for cooking.
Construction Materials: The walls of a traditional kitchen are constructed using mud, and the roofs are typically made of bamboo and palm fronds, emphasizing natural and locally sourced materials.
Modern Kitchen:
Location: Modern kitchens are integrated within the main building, seamlessly blending into the overall architecture of the home.
Ventilation: Designed with comfort in mind, modern kitchens are well-ventilated, ensuring a pleasant environment for cooking activities.
Floor Material: The floor of a modern kitchen is made of durable materials such as concrete or tile, providing a clean and easy-to-maintain surface.
Fuel Sources: In contrast to traditional kitchens, modern kitchens use more contemporary sources of fuel, such as gas or electricity, reflecting advancements in technology and convenience.
Construction Materials: The walls of a modern kitchen are constructed using concrete, offering strength and durability, while the roof is typically made of zinc, providing a modern and weather-resistant covering.
These distinctions highlight the evolution of kitchen design, with modern kitchens emphasizing convenience, efficiency, and a seamless integration into the overall structure of the home. The shift from traditional to modern kitchens is not only evident in their physical characteristics but also reflects advancements in technology, materials, and lifestyle preferences.
Factors To Be Considered When Planning A Kitchen
A well-planned kitchen is needed in the home for ease and comfortability. The following are important factors to consider:
Floor: The floor should be made of concrete, non-slippery, and easy to clean. It should also be non-absorbent of grease, not easily discolored by hot utensils. It should be reasonably resilient.
Wall: It should be strong, durable, impervious, and easy to clean.
Ventilation: Good ventilation makes the kitchen comfortable to work in; therefore, adequate provision should be made for cross ventilation to get rid of heat generated during the cooking process. It helps to prevent undesirable odor and high humidity.
Water Supply: There should be constant water supply in the kitchen for ease in working and cleaning the kitchen. A good drainage system both within and without will prevent the development of an offensive odor around the kitchen or contamination of food. The drainage system should be accessible to repair and clean.
Lighting System: This should be either artificial or natural light from the sun, while the artificial is from electricity. The fluorescent light is more suitable for the kitchen because it does not generate heat or cast a shadow. Never use colored lights.
Color Scheme: It should show good taste and blend with equipment.
Arrangement of fixed equipment and storage facilities should prevent fatigue in the kitchen.
Advantages Of A Well-Planned Kitchen
It is comfortable to work in.
It saves time.
Accidents are prevented.
It is easy to keep clean.
It reduces fatigue.
Equipment lasts longer.
Foods prepared are more hygienic because pests are prevented from entering.
Kitchen Plans
There are different types of kitchen design or layout. The major ones are;
The L-shape.
The U-shape.
The corridor.
Kitchen Equipment
Kitchen equipment comprises tools and facilities utilized in the kitchen to facilitate food preparation and simplify cooking tasks. The selection of equipment is contingent upon the kitchen user’s preferences. Considerations when choosing or acquiring equipment include:
Income or financial availability.
Kitchen size.
Safety and maintenance of the equipment.
Durability and usability.
Importance and essentiality.
Available facilities.
Appearance and design.
Types of kitchen equipment
Small equipment: Portable items like plates, bowls, trays, and covers.
Large equipment: Fixed items requiring substantial floor space, such as gas cookers, refrigerators, and electric cookers.
Mechanical equipment: Appliances utilizing electricity to streamline kitchen operations, such as blenders, food mixers, mincers, toasters, dishwashers, and potato peelers.
Refrigerator Care Tips:
Minimize door opening to prevent warm air intake.
Arrange food for optimal cold air circulation.
Avoid using sharp objects in the freezer.
Regularly defrost the refrigerator.
Thoroughly clean the refrigerator periodically.
Call a qualified service engineer at the first sign of a defect.
Factors to Consider When Choosing a Refrigerator:
Affordability.
Family’s requirements.
Interior light and thermostat control.
Suitability for local electricity supply.
Adequate compartments for food storage and freezing.
Materials Used in Making Kitchen Equipment:
Stainless Steel: Durable, corrosion-resistant, and easy to clean. Used for cookware, sinks, countertops, and appliances.
Aluminum: Known for heat conductivity, lightness, and affordability. Commonly used for pots, pans, and baking sheets.
Cast Iron: Highly durable with excellent heat retention. Used for skillets and Dutch ovens.
Copper: Offers exceptional heat conductivity but is often used as an inner lining due to reactivity with certain foods.
Non-stick Coatings: Applied to aluminum or stainless steel surfaces for easy cleaning.
Glass: Non-reactive material used in baking dishes, measuring cups, and storage containers.
Plastic: Lightweight and durable materials for cutting boards, measuring spoons, and storage containers.
Wood: Natural and gentle on cookware, used for utensils, cutting boards, and handles. Requires special care to prevent damage or contamination.
It’s crucial to follow manufacturers’ instructions for proper care and use, considering the use of food-grade materials for safety.
Cleaning Agents And Abrasives
Cleaning agents are substances designed to assist in the washing and cleaning of kitchen equipment and utensils. Soap is a commonly used cleaning agent in the kitchen, and it is categorized as either local or commercial.
Locally made cleaning agents are crafted using materials found in the local environment, offering an affordable and effective alternative. Examples include ground eggshell, pawpaw leaf, wood ash, local sandpaper leaf, coconut husk, fine sand, and soap.
On the other hand, commercial cleaning agents are industrially manufactured through specific processes. They are typically more expensive and come in various forms such as solid bars, paste, liquid, and powder. Examples include detergents, bar soaps, Morning Fresh, Windows Lane, and Silvo.
Abrasives are substances employed for grinding or polishing surfaces in the kitchen, utilized to scrub or remove dirt and stains from equipment. They can be categorized as local or commercial.
Kitchen Linen and Their Uses:
Kitchen linen comprises various types of fabric used to clean and maintain proper hygiene and safety in the kitchen. These include:
Tea Towel: Used for wiping cutlery, cook grease, glassware, and drying vegetables when necessary.
Dish Cloth: Employed to wipe kitchen equipment, tables, work areas, and sinks; they can also be used to clean up spilled liquids.
Oven Gloves/Cloth: Designed for safely handling hot pots and dishes from the oven and stovetop ranges.
Hand Towel: Used for drying hands.
String Mop: Utilized for mopping up spilled liquids or drying the floor after mopping.
Napkin: Employed for drying hands.
Muslin: Used for covering food and straining.
Safety In The Kitchen
Kitchen safety measures and devices are implemented to prevent accidents in a space known for its bustling food preparation and cooking activities. Common accidents include falls, burns, electric shocks, and accidental poisoning. To minimize these risks, the following precautions should be observed:
Avoid wearing high heels.
Promptly clean up any spilled liquids.
Prohibit the littering of banana or yam peels in the kitchen.
Wear gloves when handling hot cooking pots.
Restrict access to the kitchen for children.
Ensure adequate ventilation by opening windows to prevent suffocation.
Conduct all cutting activities on a chopping board.
Turn off electrical sockets before and after using appliances.
Replace loose sockets promptly.
Handle glassware with care.
Familiarize yourself with equipment manuals before use.
Common causes of accidents in the kitchen include lack of concentration, improper use of equipment, poor lighting, slippery floors, inappropriate clothing and footwear, haste, and failure to adhere to safety rules.
Despite these precautions, minor injuries can still occur in the kitchen. Common injuries include:
Cuts: Treat small cuts by washing with antiseptic solution, applying clean gauze, and bandaging. For large open cuts, bandage and seek medical attention.
Burns: Use a clean, wet cloth on the burn area to alleviate pain. Immerse the burnt part in clean cold water for severe pain. Do not open small burns.
Scalds: Treat scalds caused by hot water or oil similarly to burns.
Bruises: Clean the area with water, apply a soothing lotion such as calamine, and use ice or Vaseline to alleviate discomfort caused by a blow to the body.
Hygiene
Hygiene involves maintaining cleanliness for the promotion of overall health and the prevention of diseases and germs. It encompasses the adoption of effective sanitary practices in various aspects of food production, purchase, processing, and marketing.
Ensuring personal kitchen hygiene is crucial for producing clean and safe food. The initial step involves carefully selecting food items in the market, examining packaged goods, and avoiding items with substandard packaging, such as bulged cans or imperfect seals. These precautions are essential to prevent the introduction of contaminated foods and the potential transmission of disease-causing organisms into the kitchen.
Several key sanitary measures should be observed in the kitchen, including:
Thoroughly washing hands with clean water.
Drying hands before commencing cooking and after each visit to the toilet.
Avoiding long fingernails, nail polish, and jewelry on the fingers.
Keeping hair covered.
Wearing a clean apron or overall and avoiding high-heeled shoes in the kitchen.
Ensuring that any cuts or sores are properly dressed and covered.
Washing hands just before starting to cook and taking care not to sneeze or cough during the cooking process.
Maintaining kitchen hygiene involves adhering to specific rules:
Using only clean utensils and dishes for food preparation and serving.
Holding utensils and dishware by their handles to avoid touching the service surfaces.
Washing all dishes with soap and water after use, draining them by turning them upside down.
Keeping work surfaces clean and promptly wiping up any spills.
Using a clean, dry cloth for drying dishes and utensils, boiling the cloth daily after use.
Ensuring cleanliness in the refrigerator and other food storage areas.
Covering and regularly emptying dustbins.
Covering all food items while cleaning the floor and employing methods to minimize dust.