Food Preparation Techniques PDF

**Prelim Handouts (NUDIET lecture)** **Techniques in food preparation** - Baking - Cooking food using dry heat in an oven. It's commonly used for bread, pastries, and casseroles. - Boiling - Cooking food in boiling water. It\'s useful for pasta, rice, and vegetables, though it can som...

**Prelim Handouts (NUDIET lecture)** **Techniques in food preparation** - Baking - Cooking food using dry heat in an oven. It's commonly used for bread, pastries, and casseroles. - Boiling - Cooking food in boiling water. It\'s useful for pasta, rice, and vegetables, though it can sometimes lead to nutrient loss. - Steaming - Cooking food using steam, usually in a covered pot with a small amount of water. This method preserves nutrients and is ideal for vegetables and fish. - Grilling - Cooking food over direct heat, either on a grill or a stovetop. It adds a smoky flavor and is great for meats and vegetables. - Sautéing - Cooking food quickly in a small amount of oil over medium-high heat. It's perfect for vegetables and thin cuts of meat, preserving flavor and texture. - Roasting - Cooking food in an oven using dry heat, similar to baking but often at a higher temperature. It's great for meats, root vegetables, and nuts, enhancing flavor through caramelization. - Frying -Cooking food in hot oil. There are different types, such as deep-frying, pan-frying, and stir-frying. It adds a crispy texture but can increase the fat content of the food. - Blanching - Quickly boiling food and then plunging it into ice water. This technique is used to soften food slightly, enhance color, and make peeling easier. - Poaching - Gently cooking food in simmering liquid, such as water, broth, or wine. It's ideal for delicate items like eggs, fish, and fruit, preserving moisture and flavor. - Braising - Slow-cooking food partially submerged in liquid. This method is used for tougher cuts of meat, making them tender and flavorful. - Marinating - Soaking food in a seasoned liquid before cooking to enhance flavor and tenderness. It's commonly used for meats and vegetables. - Fermenting - Allowing food to undergo fermentation, which can add unique flavors and increase probiotic content. This technique is used in making yogurt, kimchi, and sourdough bread. **Scooping and Leveling** - Flour: Lightly spoon flour into the measuring cup until it's overflowing. - Then, use a straight edge, like the back of a knife, to level off the top. - Do not pack the flour down, as this can lead to too much flour and a dense final product. **Measuring Sticky Dry Ingredients** - For ingredients like cocoa powder, sift before measuring to avoid clumps. - For sticky ingredients like honey or molasses, lightly grease the measuring cup or spoon to ensure the ingredient releases easily. **Measuring Sticky Dry Ingredients** - For the most accurate measurement, especially in baking, use a kitchen scale. Weighing ingredients eliminates inconsistencies and ensures precision. **How to Peel Specific Fruits and Vegetables:** - Apples, Pears, and Potatoes: - Peeler: Use a vegetable peeler to remove the skin in long, continuous strips. - Knife: You can also use a paring knife. - Hold the fruit or potato in one hand, and carefully slice off the skin, rotating the fruit as you go. - Citrus Fruits (Oranges, Lemons, Grapefruits): - Method 1 - Hand Peeling: Score the skin with your fingernail or a knife and then peel it off by hand. - Method 2 - Knife: Cut off the top and bottom, then slice off the peel in sections, following the curve of the fruit. - Carrots, Cucumbers, and Zucchini: - Peeler: Hold the vegetable at an angle and peel from top to bottom, rotating the vegetable as you go. - Leave some skin: If you prefer, you can leave some skin on by peeling in stripes or patterns for texture and appearance. - Pineapple: - Knife: Cut off the top and bottom, stand the pineapple upright, and slice down the sides to remove the skin. Make sure to cut deep enough to remove the \"eyes.\" - Trim and Core: After peeling, trim away any remaining eyes and remove the core. - Ginger: - Spoon: Use the edge of a spoon to scrape off the skin. This method wastes less ginger compared to using a knife or peeler. **What is Digestion?** - The process by which the body breaks down food into smaller, absorbable components. It involves both mechanical and chemical processes that begin in the mouth and continue through the digestive system, including the stomach, small intestine, and large intestine. **Macronutrients** - The nutrients that the body needs in large amounts to provide energy and support vital functions. They are the primary components of our diet and are essential for growth, metabolism, and other bodily functions. **Carbohydrates** - organic compounds made up of carbon, hydrogen, and oxygen. **1. Simple carbohydrates** - **Monosaccharides:** The simplest form of carbohydrates, consisting of a single sugar molecule. - **Disaccharides:** Consist of two sugar molecules linked together. **2. Complex Carbohydrates** - **Oligosaccharides:** Consist of 3-10 linked sugar molecules. They are found in foods like onions, garlic, and legumes. - **Polysaccharides:** These are large molecules made up of many sugar units. They include starches (found in potatoes, rice, and wheat) and dietary fiber (found in whole grains, vegetables, and legumes). **Digestion of Carbohydrates** - **Mouth**: Carbohydrate digestion begins with salivary amylase breaking down starches. - **Stomach**: Little to no carbohydrate digestion occurs. - **Small Intestine**: Pancreatic amylase and brush border enzymes complete the breakdown of carbohydrates into monosaccharides. - **Absorption**: Monosaccharides are absorbed into the bloodstream and transported to the liver. - **Utilization**: Glucose is used for energy, stored as glycogen, or converted into fat if in excess. **Function of Carbohydrates** 1\. [Primary Energy Source] This energy fuels everything from basic bodily functions to intense physical activity. 2\. [Energy Storage] - Excess glucose from carbohydrates can be stored in the liver and muscles as glycogen. - When the body needs extra energy, such as between meals or during physical exertion, glycogen is broken down into glucose and released into the bloodstream. - 375gms of glucose provide energy sufficient for only about 13 hours of moderate activity. 3\. [Support Brain Function] - The brain relies heavily on glucose as its primary fuel source. Adequate carbohydrate intake is essential for maintaining cognitive function, focus, and mental clarity. 4\. [Sparing Protein] - Excess glucose from carbohydrates can be stored in the liver and muscles as glycogen. - When the body needs extra energy, such as between meals or during physical exertion, glycogen is broken down into glucose and released into the bloodstream. - 375gms of glucose provide energy sufficient for only about 13 hours of moderate activity. 5\. [Regulating Blood Sugar Levels] - The consumption of carbohydrates, especially complex carbs and those high in fiber, helps regulate blood sugar levels. - Stable blood sugar levels are crucial for maintaining energy levels and preventing fatigue 6\. [Supporting Digestive Health] - Fiber, a type of carbohydrate, promotes healthy digestion by adding bulk to stool and facilitating regular bowel movements. - It also supports the health of the gut microbiome.  A list of food items Description automatically generated  **Health effects of starch and fibers** - **Energy Production** - **Primary Energy Source:** Carbohydrates are the body\'s main source of energy. - Glucose, derived from carbohydrates, fuels all bodily activities, from basic functions like breathing to physical activity. - **Physical Performance:** Adequate carbohydrate intake is crucial for athletes and active individuals as it helps maintain energy levels during exercise. - **Blood Sugar Regulation** - **Balanced Blood Sugar:** Complex carbohydrates, especially those high in fiber, help regulate blood sugar levels by slowing down the absorption of glucose into the bloodstream. - **Risk of Blood Sugar Spikes:** Simple carbohydrates and refined starches can cause rapid spikes in blood sugar, leading to energy crashes and increased hunger. Over time, this can contribute to insulin resistance and type 2 diabetes. - **Digestive Health** - **Fiber\'s Role:** Dietary fiber, a type of carbohydrate, promotes healthy digestion by adding bulk to stool and preventing constipation. - **Gastrointestinal Issues:** Excessive intake of low-fiber carbohydrates, especially refined ones, can lead to digestive problems, such as constipation or irritable bowel syndrome (IBS). - **Weight Management** - **Satiety:** High-fiber carbohydrates, like whole grains, legumes, and vegetables, promote a feeling of fullness, which can help control appetite and prevent overeating -.**Weight Gain**: Overconsumption of simple carbohydrates and refined starches can lead to weight gain, as they are often calorie-dense and low in fiber, leading to overeating and less satiety. - **Heart Health** - **Cholesterol Reduction**: Soluble fiber, found in oats, beans, and certain fruits, can help lower LDL (bad) cholesterol levels, reducing the risk of heart disease. - **Risk of Heart Disease:** Diets high in refined carbohydrates and sugars can increase triglyceride levels and reduce HDL (good) cholesterol, both of which are risk factors for cardiovascular disease. - **Dental Health** - **Tooth Decay:** Consuming high amounts of simple sugars and refined carbohydrates increases the risk of tooth decay. Bacteria in the mouth feed on sugars, producing acids that erode tooth enamel. - **Protective Foods:** Foods that require more chewing, like fibrous vegetables, can help stimulate saliva production, which protects teeth from decay. **FAT -** also known as lipids - 1. **Simple lipids** - a type of lipid that consists primarily of fatty acids and alcohol. 2. **Compound lipids** are a type of lipid that, in addition to fatty acids and alcohol, contain other functional groups, such as phosphates, carbohydrates, or proteins. 3. **Derived Lipids** It is diverse group of biological compounds that are insoluble in water but soluble in organic solvents. They are simple derivatives from fat digestion or other more complex products. **Fatty acids -** Key refined fuel forms of fat that the cell burns for energy.  **Glygerol** A water-soluble component of triglycerides and is inconvertible with carbohydrate. After it becomes broken off in digestion, it becomes available for formation of glucose in diet. It serves as a **backbone for triglycerides and phospholipids**, which are essential components of cell membranes. When fats are metabolized, **glycerol is released into the bloodstream along with fatty acids and can be converted into glucose or used for energy production in the liver** **Uses of Glycerol** **Steroids** A class of fat-related substances that contain sterols. A main member of this group is cholesterol A complex fat-like compound found practically in all body tissues, especially in the brain and nerve tissues, bile, blood, and liver where most cholesterol is synthesized. Foods high in cholesterol: egg yolk, organ meats, shellfish and dairy fats. **The Omega 6/ Omega 3 Ratio** The ideal ratio of omega-6 to omega-3 fatty acids is a topic of ongoing research and debate. However, most experts agree that the current Western diet, with its high intake of omega-6 fatty acids and low intake of omega-3s, is suboptimal for health.  **Digestion of Fats**  **\ ** **Function of Fats** - Normally, about 95% of the fat in food is digested and absorb. - Facilitates absorption of the fat-soluble vitamins A, D, E, and K. - Provides satiety and delays onset of hunger - Contributes flavor and palatability to the diet - It is a protein-sparing because its availability reduces the need to burn protein for energy. - It is essential to maintain the constant body temperature by providing effective insulation underneath the skin **Food Sources of Fats** - **Visible Fats** - **Fats that can be seen and are typically added to foods or used in cooking. They are generally extracted from both plant and animal sources.**  - **Invisible Fats** - Fats present in foods that you can't see with the naked eye.  **Health Effects of Fats**  **Trans Fat** - Trans fats, also known as trans-unsaturated fatty acids, are a type of unsaturated fat that can have significant negative health effects. - **Types of Trans Fats** - **Naturally Occurring Trans Fats**: These are found in small amounts in some animal products like meat and dairy. - **Artificial Trans Fats:** These are created through an industrial process that adds hydrogen to liquid vegetable oils to make them more solid. This process is known as **[partial hydrogenation]** **Effects of Trans fat.** How to Avoid Eating Trans Fat - **Read Nutrition Labels:** Look for "0 g trans fat" on the Nutrition Facts label and avoid products with partially hydrogenated oils in the ingredients list - **Choose Healthier Oils:** Use vegetable oils like olive, sunflower, or canola oil instead of hydrogenated oils - **Eat Whole Foods:** Focus on fresh, less-processed foods such as fruits, vegetables, whole grains, low-fat dairy, poultry, fish, and nuts - **Limit Processed Foods:** Cut back on processed foods, especially those that are fried or baked, as they often contain trans fats - **Cook at Home:** Preparing meals at home allows you to control the ingredients and avoid trans fats found in many restaurant and fast food **Protein** - **Simple Protein** Simple proteins are composed solely of amino acids and do not contain any other chemical groups. **Examples:** - Albumins: Found in egg whites, blood serum, and milk. - Globulins: Found in blood plasma and milk - Glutelins: Found in the seeds of cereals like wheat and rice. - Prolamins: Present in grains such as wheat (gliadin), barley (hordein), and corn (zein). - Albuminoids (Scleroproteins): These include structural proteins like collagen and keratin. - Histones: Proteins associated with DNA in the cell nucleus, playing a role in gene regulation. - Protamines: Found in the sperm of fish and birds, these proteins are involved in packaging DNA - **Compound proteins** - Also known as conjugated proteins, are proteins that are combined with non-protein components called prosthetic groups. - These prosthetic groups can be organic molecules or metal ions, and they are essential for the protein's function. - **Glycoproteins:** Proteins with carbohydrate groups attached. They play roles in cell-cell recognition and immune responses. **Example: Immunoglobulins (antibodies).** - **Lipoproteins:** Proteins combined with lipids. They are important for transporting lipids in the blood. **Example: Low-density lipoprotein (LDL).** - **Metalloproteins:** Proteins that contain metal ions as prosthetic groups. They are involved in various biochemical processes. **Example: Hemoglobin (contains iron).** - **Phosphoproteins:** Proteins with phosphate groups attached. They are involved in regulating various cellular activities**. Example: Casein in milk** - **Derived Proteins** - Proteins that have been modified from their original form through processes such as hydrolysis, denaturation, or other chemical treatments. These modifications can result in proteins with different properties and functions compared to their original forms. **Digestion of protein**  **Functions of Proteins** a. **Structural Support:** Proteins like collagen and keratin provide structural support to cells and tissues, maintaining the integrity of skin, hair, nails, and connective tissues b. **Enzymatic Activity:** Enzymes are proteins that catalyse biochemical reactions, speeding up metabolic processes in the body. Examples include digestive enzymes like amylase and lactase c. **Transport and Storage:** Proteins such as hemoglobin transport oxygen in the blood, while others like ferritin store iron in the liver. d. **Hormonal Regulation**: Some proteins function as hormones, which are chemical messengers that regulate various physiological processes. Examples include insulin, which regulates blood sugar levels, and growth hormone e. **Immune Response:** Antibodies are proteins that recognize and neutralize pathogens like bacteria and viruses, playing a crucial role in the immune system. f. **Movement:** Proteins like actin and myosin are involved in muscle contraction and movement g. **Nutrient Storage:** Some proteins store nutrients for later use. For example, casein in milk stores amino acids h. **Cell Signaling:** Proteins are involved in transmitting signals within and between cells, helping to coordinate various cellular activities **Protein-Energy Malnutrition (PEM),** also known as Protein-Energy Undernutrition (PEU), is a condition resulting from a deficiency of protein and calories. Types of PEM: - **Marasmus:** This form is characterized by severe weight loss and muscle wasting due to a deficiency in both calories and protein. It often affects infants and very young children - **Kwashiorkor:** This type is marked by edema (swelling), an enlarged liver, and skin changes, primarily due to a severe protein deficiency while calorie intake might still be adequate - Inadequate Nutrient Intake: Insufficient consumption of protein and calories. - Chronic Illnesses: Conditions like chronic renal disease or cancer Treatment of PEM - Nutritional Rehabilitation: Gradual reintroduction of nutrients, starting with fluids and electrolytes, followed by protein and calorie-rich foods - Medical Care: Addressing underlying health issues and monitoring for complications