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FNU 232 Notes Textbook 2023-
Basic Food Science (Louisiana Tech University)
Food Patterns
Food professionals need to be in tune with the way people are choosing to eat, so food in the marketplace and in commercial venues will meet expectations for palatability and safety. Because patterns and preferences change, there is a continuing need for surveying and reviewing the food scene on an ongoing basis. Influences on Diet: ● Health problems or concerns play an important role in food selection for many shoppers. Some people with dietary restrictions due to problems such as diabetes, high blood pressure, or lactose or gluten intolerance are avid label readers as they seek suitable products. Issues such as nutrition and food safety are prominent in the minds of many as they shop for food to promote their health and well-being. ● Lifestyles and the economy are strong influences on how and what people eat. ● Income or budget also has an important influence on where and what a person eats. The rapidly rising cost of food is causing many people, particularly those on limited incomes, to be increasingly restricted in the foods they buy.
Dining Venues
The recent economic downturn has increased the numbers of people eating meals at home, especially breakfast and dinner. ● Meals at home are an excellent opportunity for family members to coordinate and catch up with the happenings of the day. ○ Breakfasts featuring fried eggs and bacon and lunches highlighting comfort foods tend to draw customers who are focused more on flavor than health. Feeding Others: Schools, hospitals, and other institutional settings usually have cafeterias or dining rooms where people eat, either through choice or necessity (Figure 1.4). The quality of food served varies considerably from place to place, ranging from acceptable to excellent. The price also ranges from free school lunches for children who qualify under the federal program to $1500 or more per day in a special hospital unit catering to wealthy clients willing to pay for gourmet meals prepared by a highly trained chef.
Feeding Others: Restaurants are the venue selected by many people when dining out rather than a fast-food operation. For special occasions, the choice may be an upscale restaurant that features beautiful food presentations and very attentive service.
Food Choices
Those that have been familiar since childhood usually continue to be favorites throughout life. These and other choices are influenced by such factors as ethnic heritage, resources (time for preparation and money), personal preferences, and health. ● Diners make choices with their forks when they eat. Favorite foods quickly vanish from the table at dinner, but other items may be destined to become leftovers, or even may be thrown away. Impact on Health Excess weight and obesity are an ever-increasing threat that is creating a national health crisis due to poor food choices and too little exercise. The influence of overweight and obesity on health is well recognized; the risks of heart attacks, strokes, and diabetes increase significantly when people are too heavy. ★ Dietary habits throughout life contribute to a person’s physical condition, but it still is possible to alleviate some of the problems that have devel-oped over the years. By eating balanced, colorful meals featuring fresh ingredients, in amounts that help to achieve and maintain a healthy weight, people can promote personal well-being. National Organic Program- Legislation defining the production standards for produce (at least 95 percent of produce must not have been treated with sewage-sludge–based or petroleumbased fertilizers, conventional pesticides, ionizing radiation, or bio-engineering) to be labeled organic. Genetically Modified Organism (GMO)- Plants (and food) that have been modified by genetic engi-neering to enhance desired characteristics. Awareness of the potential protection against cancer that some phytochemi-cals (e.g., various carotenoids) provide has heightened consumer demand for foods containing them. The food industry is incorporating various nutrients and substances with recognized health benefits because of the increased interest in healthful eating Aroma- Volatile com-pounds perceived by the olfactory receptors; odors wafting from the kitchen hint of the pleasure to come. Bakeries sometimes deliberately vent the aroma from their ovens outside to lure potential customers. Aromas can be negative or positive.
● Flavor can be judged by breathing in and exhaling imme-diately after swallowing or while a bite is held in the mouth with lips closed tightly so that the volatile substances blend with taste sensations. ● Color is an important aspect of food that judges may be asked to evaluate, either for differences between samples or to indi-cate a preference. ● Texture can be detected by touch or feel in the mouth, characteristics that may be noted on a scorecard by such descriptions as tenderness or mouthfeel. Hedonic ratings by consumer panels can guide researchers toward the goal of a product that will be accepted and enjoyed. EX.: Smiley face card Objective evaluation ; Physical and chemical methods may be used to measure various aspects of food in a laboratory. Physical methods include measurements of volume, specific gravity, moisture, texture, rheology (flow and deformation), color, and cell structure. Career Opportunities for Food Professionals Registered Dietitian- Person who has passed the registration examina-tion after completing an approved baccalaureate or master’s program in food and nutrition and clinical experience. Dietetic Technician, registered (dtr)- Graduate of an approved two-year dietetic techni-cian associate degree who passes the dietetic technician registration examination. ● DTRs often work under the direction of an RD in hospitals or other health care settings. Chapter 2- KEY CONCEPTS
- Food can provide all the nutrients (carbohydrates, lipids, proteins, vitamins, and minerals) needed for good health.
- Carbohydrates, fats, and proteins are the nutrients that provide energy, while vitamins and minerals perform many unique functions (e.g., vitamin D and calcium are essential for bone growth and maintenance).
- Recommendations for eating for good health include the Dietary Reference Intake values (DRIs), designed for professionals to use in assessing dietary adequacy; Dietary Guidelines for Americans, 2010; and MyPlate, a nutrition education tool designed to help the public know what to eat for good health.
- Good nutrition can be promoted by buying a variety and an appropriate quantity of food and preparing it to be appetizing and nutritious. Macronutrients- Nutrients needed in large quantities: carbohydrates, lipids (fats), and proteins.
Calorie Unit- of energy provided in a food. One calorie (also called a kilocalorie) is the amount of heat energy required to raise 1 kilogram of water 1°C at sea level ● Too many calories (or kilocalories) provide more energy than the body uses, and the surplus is converted into fat and stored. Overweight and obesity are so prevalent in the United States today that they are considered to be an epidemic that is raising major health concerns. Nutrient Density- The amount of nutrients in relation to the calories in a food; high nutrient density means a food is high in nutrients when compared with its caloric content. Carbohydrates (e.g., sugars, starch, fiber) are primary sources of energy and comprise a significant part of the diet; 4 calories per gram ● Fiber- Components of food not digested and absorbed; cellulose, pectic substances, and gums are plant carbo-hydrates contributing to the fiber content of the diet. Lipids are fatty substances that are a concentrated source of calories; 9 calories per gram. In addition to being sources of energy, they carry the fat-soluble vitamins (vitamins A, D, E, and K) and provide the essential fatty acid, linoleic acid, and omega-3 fatty acids. Proteins are essential for their amino acids, which are needed to synthesize many important components of the body; 4 calories per gram. Muscle tissue, connective tissue, blood, antibodies, and many other substances contain proteins, each of which is made to meet specific physical requirements. Essential Amino Acids- Amino acids that must be provided in the diet to maintain life and promote growth; unable to be synthesized in the body ● If no animal sources are eaten, at least two of the plant sources should be included in the same meal to provide an adequate blend of complementary amino acids. Minerals- Natural elements in foods that remain as ash if a food is burned; many are essential nutrients. ● Those found in the largest amounts—calcium, phosphorus, potassium, sulfur, sodium, chloride, and magnesium—are termed macrominerals. ● Micronutrient minerals include iron, zinc, manganese, selenium, copper, and iodine On the basis of their solubility, vitamins A, D, E, and K are classified as fat soluble and the B vitamins and vitamin C (ascorbic acid) are water soluble. The B vitamins include vitamin B1 (thiamin), vitamin B2 (riboflavin), vitamin B3 (niacin), pantothenic acid, folacin (folic acid), vitamin B6 (pyridoxine), vitamin B12 (cobalamin), and biotin.
Water Solubility- Some nutrients, notably the water-soluble vitamins, may be dissolved into the surrounding cooking water during preparation. This is not a problem if all of the cooking liquid is to be consumed with the food, as would be the case in a soup, but it does represent a problem in such items as boiled vegetables. Intense heat may cause proteins to be utilized less well by the body than is the case when mild cooking temperatures are used. This is particularly true of excessively high temperatures used in some deep-fat frying or in some instances of baking. Oxidation- Certain nutrients, particularly some of the vitamins (vitamin C, vitamin A, thiamin, riboflavin, vitamin B6, and folacin) and the polyunsaturated fatty acids, may be unable to perform their usual roles in the body because of oxidation. Such reactions occur when cut surfaces are exposed to air. Light- A few nutrients are sensitive to light and will lose their vitamin activity when exposed to light for a period of time. Riboflavin is the nutrient that is most sensitive to light. ph. The pH—that is, whether acidic or alkaline—of the medium in which a food is placed will have an effect on the nutritive value of the food. Most vitamins (particularly thiamin) are quite stable in acids…
CHAPTER 3: Food Safety
- Food safety requires careful temperature control of foods from farm to table.
- Enforcement of high standards of sanitation for all food handlers is needed in all environments where food is being stored, prepared, and served.
- Food-borne illnesses, ranging from causing physical discomfort to death, can be caused by various bacteria, viruses, molds, parasites, and chemicals that may be found in some foods that have not been refrigerated properly and handled safely.
- The FDA regulates additives that may be incorporated in food products for a variety of reasons, for example, to improve nutritional value, enhance such sensory characteristics as flavor, and for other reasons specified by law.
- Several federal agencies share responsibility for the safety of the nation’s food supply. Harmful and infective agents may be introduced during any of the following steps:
- Growing
- Harvesting
- Marketing (including transportation and storage)
- Storing and preparing (in the home or in commercial operations). Bacteria- Round, rod-shaped, or spiral single-celled microorganisms in soil, water, or organic matter. Molds- Filamentous, often wooly fungi that can thrive on damp surfaces, such as cheeses. Aflatoxin- Mycotoxin produced by molds (Aspergillus flavus or Aspergillus parasiticus) in some food crops, for example, peanuts grown in mold-contaminated soil or stored in a damp place. Virus- Submicroscopic molecules composed of genetic material surrounded by a protein coat; some can cause diseases in their host.
effectiveness in preventing multiplication and/or in killing the bacteria. Contamination needs to be avoided by:
- using only pasteurized milk and dairy products
- keeping raw foods separate from cooked foods until very close to serving time
- keeping all cutting boards and other items that contact food meticulously clean
- washing all raw foods before eating
- maintaining foods below 40°F (5°C) or above 140°F (60°C)
- cooking poultry to 180°F (82°C) and other meats and fish to 160°F (71°C). Escherichia Coli (e. coli)- Group of bacteria often found as the cause of food-borne illnesses. Shigella Boydii- Bacteria spread by fecal contamina-tion in water or food Noroviruses- Virus that can cause hepatitis A, spread easily through contaminated water and by infected unsanitary food handlers who fail to wash their hands adequately in hot, soapy water. Parasite- Organism living within another organism and deriving its sustenance from the host; worms, such as Trichinella spiralis, can cause weight loss and other health problems in people. Trichinosis- Illness caused by eating viable T. spiralis, a parasite sometimes contained in undercooked pork. Trichinella Spiralis: Parasite sometimes found in pork; causes trichinosis in humans. Shellfish Poisoning- Life-threatening poisoning from saxitoxin produced in shellfish feeding on Gonyaulax catenella; characterized by loss of strength and respiratory failure. ● transmitted through scallops, clams, and mussels, as well as oysters Saxitoxin- Neurotoxin from G. catanella that accumulates in shellfish during conditions of red tide; causes shellfish poisoning and can be fatal. CHAPTER 4: PREPERATION EQUIPMENT Successful preparation of recipes begins with accurate measurement of ingredi-ents. Cookbooks list the amount of each ingredient based on standard measuring techniques using standardized measuring equipment (Figure 4.1). The equip-ment needed includes a set of graduated measuring cups (1 cup, 1/2 cup, 1/3 cup, and 1/4 cup measures) for measuring dry ingredients, a 1-cup glass measuring cup with measurements indicated on the sides and a
pouring spout for measuring liquids, and a set of graduated measuring spoons (1 tablespoon, 1 teaspoon, 1/2 teaspoon, and 1/4 teaspoon). ❏ Liquids are measured in a glass measuring cup ❏ Other ingredients are measured in graduated measuring cups and spoons. ❏ Oils are measured by pouring into a glass measuring cup until the bottom of the meniscus (the curved upper surface of liquid) of the oil reaches the desired marker on the cup. Mixers: An electric mixer is a convenience and saves energy. A mixer on a stand is more powerful than handheld mixers and frees the hands for adding ingredients. These mixers can be released from the stand and operated while being held by hand. Cutlery: Essential pieces of cutlery include a paring knife, French or chef’s knife, slicing knife, and butcher knife. There are many special knives that are convenient to add when possible (Figure 4.3). Knives of high-quality construction with blades of forged steel and that are well balanced are invalu-able and can be used for many years. To keep these knives sharp, a sharpening device is needed. Equipment: Double boiler- two-part pan and lid designed to hold water in the bottom pan and the food in the top; its French name is bain-marie. Frying pans usually have sides with a bit of a slope, which makes it easy to push a spatula under the food being fried. Safety in the Kitchen: Watch for spills; They need to be cleaned up immediately to eliminate the hazard. Electrical appliances should be checked to be sure they are in the “off” position before they are plugged in. Hair needs to be confined not only for sanitary reasons but also to keep it from accidentally getting caught in appliances. Knives are an obvious hazard. Always hold a knife by the handle; the blade should be pointed at the floor when a knife is carried. If it is laid on the counter, the handle should be placed so that it is more convenient to reach than the blade. To avoid burns, pan handles need to be pointed toward the edge of the range and never extend over the front edge or other burners.
Many substances in foods are much larger than a millimicron. Proteins, for example, are large molecules that are unable to go into solution but form a colloidal dispersion. Therefore, they have no appreciable effect on the boiling point. Gelatin, starch, gums, cornmeal, and countless other food items can be added to boiling water in varying concentrations, but they will not cause a measurable change in the boiling point because they form coarse suspensions, not true solutions. Colloidal Dispersion- system containing protein or other molecules or particles between 1 and 100 millimicrons in size dispersed in a continuous phase, in this case in water. Coarse Suspension Dispersion of particles larger than colloidal size mixed in water or other liquid. Frying Temperatures With the exception of sugar solutions, cookery in boiling water is done at 212°F (100°C) or less unless a pressurized system is used. However, much higher temperatures can be utilized when fat is the cooking medium, because fat does not boil even when the temperature rises as high as 475°F (246°C). Fat can be maintained at around 375°F (190°C). Thermometers To help ensure good temperature control in food preparation and handling, appropriate thermometers are used: generally, a candy thermometer, a deep-fat frying thermometer, and a meat thermometer. ● Candy: thermometer for candy making will need to have an upper limit of approximately 325°F (163°C) to allow a margin of safety above the probable high of 300°F (149°C) needed for some candies ● Deep-Fat: deep-fat frying thermometer will have an upper limit of at least 500°F (260°C). ● Meat: meat thermometer will register up to about 185°F (85°C) Principles of Heating Foods Conduction- transfer of heat from one molecule to the next; heat is transferred directly from one molecule to another. In cooking, heat is transferred by conduction from the metal of an electrical coil on a range directly to the metal of the pan in which a food is being heated. Convection- transfer of heat throughout a system by movement of currents of heated air, water, or other liquid. The convection oven is based on this principle. By forcing the circulation of heated air currents in this type of oven, foods will be heated and baked significantly more quickly than they will be when circulation of heated air is limited.
Radiation- transfer of energy directly from the source to the food being heated. The energy involved in radiation from broiling is in the infrared range (somewhat longer waves than are in the range of visible light). Microwave Oven- special type of oven that is able to heat food by sending waves of 915 or 2,450 MHz from a magnetron tube directly into foods, where water and/or fat molecules vibrate and heat foods. ● utilize the infrared frequency range ● microwaves penetrate as much as an inch into a food, causing rapid vibra-tions of individual molecules of water or fat. It is these vibrations that cause the food to begin to heat rapidly. Magnetron Tube- tube generating microwaves in a microwave oven. Microwave- Form of electromagnetic energy; 915 and 2,450 MHz are the assigned frequencies for microwave ovens. Vegetables 1.Vegetables are important in meals to provide not only an array of minerals and vitamins but also color, flavor, and textural contrasts.
- Various parts of plants are eaten as vegetables, either raw or cooked (e.g., boiled, steamed, roasted, or fried).
- Careful selection and handling of fresh, frozen, and canned vegetables are necessary to procure the desired quality.
- Preparation of vegetables should be done to optimize sensory qualities (color, aroma, flavor, and texture) and to retain nutrients. Phytochemicals- Substances contained in plants that provide some protection against heart disease and certain cancers. ● Vegetables contain phytochemicals such as beta-carotene and lycopene that may play protective roles in reducing the risk of such potential health problems as cancer and heart disease Vegetables have the potential for adding wonderful colors, textures, and intriguing flavors to a meal. Anise, also called sweet fennel, is unique among vegetables because of its flavor; in fact, it can be described as licorice-flavored celery. The bulb can be eaten raw or may be cut up and cooked by boiling, steaming, or braising. Storage following purchase should be in the hydrator drawer of the refrigerator.
Carrots have lacy tops that suggest the fact that they belong to the parsley family; other relatives of this varied group include celery and parsnips. The bright orange color and delicate flavor of high-quality carrots have made them a favorite vegetable, either raw or cooked. Cauliflower should be a white, compact head, free of dark blemishes or spots. Its cabbage-like flavor indicates its relationship to cabbage. Some people use small flowerets raw for dipping or in vegetable salads. In addition, the head may be cooked whole by boiling, or individual flowerets may be broken off and boiled or steamed. Celery is one of the stem vegetables particularly popular in its raw form. Pascal is the variety generally preferred because of its reduced stringiness and mild flavor. Celeriac is a relative of celery. However, it is the bulb-like root that is used for the vegetable (Figure 5.6). Its large cross section requires thorough cooking to tenderize it, a problem that can be minimized by cutting the root into cubes before cooking. The gnarled skin of celeriac should be removed. Vegetable acceptance is dependent upon: Texture (mouthfeel) Color Flavor Structure of a vegetable generally includes: ● Dermal Tissue: outer covering ● Vascular System: transport system ● Parenchyma Cells: pulp Rigidity to vegetable structure is provided by: ● Cellulose ● Pectic substances ● Hemicellulose
Flavor ● Organic acids- The major organic acids in vegetables are malic and citric acids, malic acid being the most abundant. Succinic, fumaric, quinic, tartaric, malonic, shikimic, isocitric, and t-aconitic acids have also been detected in vegetables Vegetable Color Eyes: ● Acceptance ● Appeal 3 Principle Pigment Categories ● Chlorophyll: green pigements ● Chlorophyll a : Intense blue-green ● Chlorophyll b: Yellow-green ● Pheophytin a: Pale green-gray ● Pheophytin b: : Olive green Carontenoids ● Beta-carotenes: red-orange Flavenoids ● Anthocyanins: pigments that give red, purple, and blue plants their rich coloring ● Anthocyanins: Refer to Table 5.2: Common Vegetable Pigments
● Organic Food Production Act of 1990- The Organic Foods Production Act (OFPA), enacted under Title 21 of the 1990 Farm Bill, served to establish uniform national standards for the production and handling of foods labeled as “organic.” ● Organic Seal Standards- In order to label a product as "Organic," the product must have the following characteristics: Contain at least 95% organic ingredients. The remaining 5% must be allowed ingredients. Any agricultural ingredients in the product must be organic unless unavailable. Consumer: knowledge and experience ● Crispness, color, free from blemishes, variety, cooking purposes, etc. Example: Potatoes Waxy Potatoes- relatively high in sugar and low in starch Non-waxy (mealy) Potatoes- a high specific gravity; they will sink to the bottom of a solution containing 11 parts of water to 1 part salt. Canned and Frozen Vegetables Advantages: Canned Vegetables ● Convenient to store ● Quick to prepare ● Extended shelf-life Frozen Vegetables ● Bright Colors Disadvantages: Canned Vegetables ● Soft texture ● Dull in color Frozen Vegetables
● Freezer space required Grading Standards Grading Standards: established by USDA 3 Grades ● US Grade A or Fancy ● US Grade B or Extra Standard ● US Grade C or Standard Vegetable Storage- Refrigeration ● Slows respiration ● Maintians moisture level ● Exceptions; some vegetables do not work well in the refrigeration; Garlic, Onions, and Shallots etc. Menu Planning: Factors Influencing Selection: ● Color ● Texture ● Shape ● Flavor Nutrient Retention ● Method of preparation ● Cooking time
