Food Quality Factors 4z611

6 Quality Factors in Foods After reading this chapter, you should be able to: ● Describe the influence of color on food quality ● Identify the instrument that could be used to measure food texture ● Discuss the influence of color, texture, size, and shape on consumer acceptance ● Describe how water changes texture ● Identify six words used to describe food flavor ● Describe sensory methods humans use to determine food flavor ● Discuss three factors that can affect food flavor ● Explain three means for maintaining or assessing quality in foods ● Describe the role the USDA plays in food quality

astringency chroma GMP HAC hue

Q

Maillard reaction phenolic compounds pigment rheology standards

texture TQM value volatile

uality of a food product involves maintenance or improvement of the key attributes of the product—including color, flavor, texture, safety, healthfulness, shelf life, and convenience. To maintain quality, it is important to control microbiological spoilage, enzymatic degradation, and chemical degradation. These components of quality depend upon the composition of the food, processing methods, packaging, and storage.

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Quality Factors in Foods Chapter 6

APPEARANCE FACTORS Of the sensory attributes of food, those related to appearance are the most susceptible to objective measurement, but appearance is important to the consumers. They have certain expectations of how food should look. Two separate categories of appearance include: 1. Color attributes 2. Geometric attributes (size and shape)

Color Of these two, color is by far the most important. Consumers expect meat to be red, apple juice to be light brown and clear, orange juice to be orange, egg yolks to be bright yellow-orange, and so on. Food color measurements provide an objective index of food quality. Color is an indication of ripeness or spoilage. The end point of cooking processes is judged by color. Changes in expected colors can also indicate problems with the processing or packaging. Browns and blackish colors can be either enzymatic or nonenzymatic reactions. The major nonenzymatic reaction of greatest interest to scientists is the Maillard reaction, which is the dominant browning reaction. Other less explained reactions include blackening in potatoes or the browning in orange juice. The enzymatic browning found widespread in fruits and selected vegetables is due to the enzymatic catalyzed oxidation of the phenolic compounds. Naturally occurring pigments play a role in food color. Water-soluble pigments may be categorized as anthocyanins and anthoxthanins. Lesser known water-soluble pigments include the leucoanthocyanins. Fat-soluble plant pigments are primarily categorized into the chlorophyll and carotenoid pigments. These green and orange-yellow pigments considerably impact the color. Myoglobins contribute to the color of meat.

Measuring Color In order to maintain quality, the color of food products must be measured and standardized. If a food is transparent, like a juice or a colored extract, colorimeters or spectrophotometers can be used for color measurement. The color of liquid or solid foods can be measured by comparing their reflected color to defined (standardized) color tiles or chips. For a further measurement of color, reflected light from a food can be divided into three components: value, hue, and chroma. The color of a food can be precisely

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defined with numbers for these three components with tri-stimulus colorimetry. Instruments such as the Hunterlab Color and Color Difference Meter measure the value, hue, and chroma of foods for comparisons.

Size and Shape Depending on the product, consumers expect foods to have certain sizes and shapes (Figure 6-1). For example, consumers have some idea of what an ideal french fry should look like, or an apple, or a cookie, or a pickle. Size and shape are easily measured. Fruits and vegetables are graded based on their size and shape, and this is done by the openings they will through during grading. Now computerized electronic equipment can determine the size and shape of foods.

TEXTURAL FACTORS Consumers expect gum to be chewy, crackers to be crisp, steak to be tender, cookies to be soft, and breakfast cereal to be crunchy. The texture of food refers to the qualities felt with the fingers, the

FIGURE 6-1 Consumers expect foods to have a particular shape.

Quality Factors in Foods Chapter 6

tongue, or the teeth. Textures in food vary widely, but any departure from what the consumer expects is a quality defect. Texture is a mechanical behavior of foods measured by sensory (physiological/psychological) or physical (rheology) means. Rheology is the study of the science of deformation of matter. The four main reasons for studying rheology include: 1. Insight into structure 2. Information used in raw material and process control in industry 3. Applications to machine design 4. Relation to consumer acceptance Regardless of the reason for studying texture, classification and understanding are difficult because of the enormous range of materials. Moreover, food materials behave differently under different conditions (Figure 6-2). Texture testing in foods is based upon the action of stress and strain. Many of the methods are based upon compression, shearing, shear-pressure, cutting, or tensile strength. For example, the compressimeter was used to determine the compressibility of cakes and other “spongelike” products. Historically, the penetrometer, has been used to measure gel strength. The Warner-Bratzler shear apparatus has been the standard method of evaluating meat tenderness. The Instron has adapted many of the historical texture

FIGURE 6-2 Texture is important to consumers, and scientists measure the texture of different foods. (Source: USDA, ARS Image Gallery)

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measuring instruments. It measures elasticity. The Brookfield viscometer will measure the viscosity in of Brookfield units. Other instruments used to measure texture include a succulometer and a tenderometer. Changes in texture are often due to water status. Fresh fruits and vegetables become soggy as cells break down and lose water. On the other hand if dried fruits take on water, their texture changes. Bread and cake lose water as they become stale. If crackers, cookies, and pretzels take up water, they become soft and undesirable. Various methods are used to control the texture of processed foods. Lipids (fats) are softeners and lubricants used in cakes. Starch and gums are used as thickeners. Protein can also be a thickener, or if coagulated as in baked bread, it can form a rigid structure. Depending on its concentration in a product, sugar can add body as in soft drinks or in other products add chewiness, or in greater concentrations it can thicken and add chewiness or brittleness.

FLAVOR FACTORS Food flavor includes taste sensations perceived by the tongue— sweet, salty, sour, and bitter—and smells perceived by the nose. Often the flavor and smell (aroma) are used interchangeably. Food flavor and aroma are difficult to measure and difficult to get people to agree on. A part of food science called sensory science is dedicated to finding ways to help humans accurately describe the flavors and other sensory properties of their food. Flavor, like color and texture, is a quality factor. It influences the decision to purchase and to consume a food product. Food flavor is a combination of taste and smell, and it is very subjective and difficult to measure. People differ in their ability to detect tastes and odors. People also differ in their preferences for these. Besides the tastes of sweet, salty, sour, and bitter (see Figure 6-3), an endless number of compounds give food characteristic aromas, such as ●

Fruity

●

Astringency

●

Sulfur

●

Hot

Sweetness may result from sugars like arabinose, fructose, galactose, glucose, riboses, xylose, and other sweetners. Organic acids may be perceived on the bottom of the tongue. Some of these

Quality Factors in Foods Chapter 6

FIGURE 6-3 Taste areas on our tongues help perceive flavor.

Bitter Sour Salt Sweet

common acids are citric, isocitric, malic, oxalic, tartaric, and succinic acids. The fruity flavors are often esters, alcohols, ethers, or ketones. Many of these are volatile and are associated with acids. Phenolic compounds are closely related to the sensory and nutritional qualities of plants. They are found in many fruits, including apples, apricots, peaches, pears, bananas, and grapes; and vegetables such as avocado, eggplant, and potatoes, and contribute to color, astringency, bitterness, and aroma. Most phenolic

TASTE OF HOT CHILI PEPPERS The active ingredient in hot chili peppers is a substance called capsaicin. It is so potent that even a minute amount has a strong effect. Why does capsaicin taste so “hot”? There are receptor molecules in the membranes of certain pain sensor nerves that respond strongly to capsaicin molecules. Heat, acids, and other various chemical or physical stimuli, including injuries, also activate the same pain receptors. Capsaicin’s “hot” taste is created by directly activating the heat/pain sensory system. Once capsaicin triggers a receptor, the same receptor becomes even more sensitive to heat, making warm soup taste even hotter. For more information about capsaicin, search the Web or visit these Web sites: <www.apnet.com/inscight/10221997/graphb.htm> <www.steveweiss.com/products.html>

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compounds are found around the vascular tissues in plants, but they have the potential to react with other components in the plant as damage to the structure occurs during handling and processing. Loss of nutrients and changes in color and flavor occur in foods due to the phenolic compounds’ reaction with polyphenol oxidase, or PPO, an enzyme that catalyzes oxidation. The sense of taste is a powerful predictor of food selection. The four main tastes the body experiences are sweet, sour, salty, and bitter. Humans like sweet-tasting foods. Possibly this preference for sweet is a holdover from ancient ancestors, who found that sweetness indicated that the food provided energy. Judgment of flavor is often influenced by color and texture. Flavors such as cherry, raspberry, and strawberry are associated with the color red. Beef flavor is brown. Actually, the flavor essences are colorless. As for texture, people expect potato chips to be crunchy and gelatin to be soft and cool. Depending on the food, flavor can also be influenced by: ●

Bacteria

●

Yeasts

●

Molds

●

Enzymes

●

Heat/cold

●

Moisture/dryness

●

Light

●

Time

●

Additives

Finally, depending on the product, the influence these factors have on a food flavor can be positive or negative and sometimes differs depending on the person.

Taste s For consumer quality acceptance, the best method of measuring taste is to have people taste the products. Taste s may be a group of professionals, or they may be a group of customers. Typically taste s are in separate booths so that they cannot influence each other. Food samples are coded with letters and numbers, and tasters are given an evaluation form to complete as they taste the product and evaluate it (Figure 6-4).

Quality Factors in Foods Chapter 6

FIGURE 6-4 Taste test s help determine the acceptance of new products. (Source: USDA, ARS Image Gallery)

ADDITIONAL QUALITY FACTORS Additional quality factors include shelf life, safety, healthfulness, and convenience. The extension of storage life of products generally involves heat treatments, irradiation, refrigeration or freezing, or reduction of water activity by either addition of water-binding agents, like sugars, or drying. In many cases compromises are made to achieve desired shelf life or convenience. Such processes, though improving shelf life, almost always have some effect on the components of the food. The factors that influence changes of various ingredients in foods include the following: proteins, lipids, carbohydrates, vitamins, chemicals, and microbiological characteristics.

Proteins Heat denaturation changes solubility and texture of foods; light oxidation of protein causes off flavors. Enzymatic degradation of protein can cause changes in body and texture and also bitter flavors. Freezing can alter protein conformation and solubility in some cases.

Lipids Enzymatic hydrolysis of lipids can cause off flavors, such as soapy or goaty, depending on type of oil. This also makes frying oils

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unsuitable for use. It can change functionality and crystallization properties. Oxidation of unsaturated fatty acids causes off flavors.

Carbohydrates High-heat treatments cause interactions between reducing sugars and amino groups to give Maillard browning and changes in flavor. Hydrolysis of starch and gums can change texture of food systems. Some starches can be degraded by enzymes or under acidic conditions.

Vitamins Depending upon the vitamin, losses can occur when the food is heated, exposed to light, or to oxygen.

Chemicals and Microbiological Characteristics Ensuring the safety of food involves careful control of the process from the farm gate to the consumer. Safety includes control of both chemical and microbiological characteristics of the product. Most processing places emphasis on microbial control, and often has as its objective the elimination of organisms or prevention of their growth. Processes that are aimed at prevention of growth include: ● Irradiation ● Refrigeration ● Freezing ● Drying ● Control of water activity (addition of salt, sugars, polyols, and so forth) Processes that are aimed at minimizing organisms include: ● Pasteurization ● Sterilization (canning) ● Cleaning and sanitizing ● Membrane processing A further method of processing that is aimed at the control of undesirable microflora is the deliberate addition of microorganisms and the use of fermentation. Safety from a chemical viewpoint generally relates to keeping undesirable chemicals, such as pesticides, insecticides, and antibiotics, out of the food supply. Making sure that food products are

Quality Factors in Foods Chapter 6

free from extraneous matter (metal, glass, wood, etc.) is another facet of food safety. Today’s consumers want food products that are convenient to use and still have all the qualities of a fresh product.

QUALITY STANDARDS Quality standards help ensure food quality (see Figure 6-5). Types of standards include research standards, trade standards, and government standards. Research standards are set up by a company to help ensure the quality of its products in a competitive market. Trade standards are established by of an industry. These are voluntary and assure at least minimum acceptable quality. As for government standards, some are mandatory and some are optional. Grade standards established by the government provide a common language for producers, dealers, and consumers for buying and selling.

Quality Standards USDA/AMS In cooperation with industry, the Agricultural Marketing Service (AMS) of the USDA develops and maintains official U.S. quality standards and grades for hundreds of agricultural products (see Figure 6-6). These standards are based on attributes which describe the value, utility, and entire range of quality for each product in the following categories: ● Nuts and specialty crops ● Dairy ● Poultry and eggs (including rabbits) ● Fresh fruits and vegetables (including fresh fruits and vegetables for processing) ● Processed fruits and vegetables (including juices and sugar products) ● Livestock (including wool and mohair) The USDA/AMS Web site is <www.ams.usda.gov/standards/ index.htm>.

Grading and Certification Quality grading (a -fee service) is based on the standards developed for each product (see Figure 6-7). Grading services are often operated cooperatively with state departments of agriculture. Quality grades provide a common language among buyers and sellers, which in turn assures consistent quality for consumers.

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Characteristic Live Requirements GLA-phenotype (51% black)

Certified Angus Beef

Sterling Silver Excel Corp.

X

GLA-genotype

SYSCO Supreme Angus Beef

SYSCO Imperial Angus Beef

X X

X X

(Red Angus)

(Red Angus)

X X

Certified Hereford Beef

Farmland Angus Beef

Wal-Mart Angus Beef

Packerland Angus Beef1

Omaha Steaks Angus Beef

X

X

X

X

Page 1 of 5 Excel Corp. Angus Pride X X (Red Angus)

Quality Factors U.S. Prime U.S. Choice U.S. Select Marbling requirements Medium or fine marbling texture Maturitya Yield Factors Yield grade

X X

X X

X X

Modest00 or higher X A

Modest00 or higher X A or B

Modest00 or higher X A

3.9b or lower

X X Small00 Slight00– or higher Moderate99 X X A A 3.9 or lower

X X

X X

X X

X X

X X

Small50 or higher

Modest00 or higher X A

Small00 or higher

Small50 or higher

A

Modest00 or higher X A

3.9 or lower

3.9b or lower

3.9b or lower

A 3.9 or lower

Fat thickness (inches) Ribeye area (square inches) Musclingc X X X X X X X X X Hot carcass weight (pounds) 600–950 Carcass Characteristics No ribeye muscle internal hemorrhages X X X X X X X X X X Free of “dark cutting” characteristics X X X X X X X X X X Hump height (inches) ≤2 ≤2 ≤2 ≤2 ≤2 ≤2 ≤2 ≤2 ≤2 Steer and heifer beef carcasses X X X X X X X X X X USDA Information Schedule number G1 G2 G9 G9 G10 G14 G16 G17 G18 G19 Initial release date 1978 Jul 98 Dec 96 Dec 96 Jan 96 Dec 96 Mar 96 Jun 98 Feb 97 May 98 Effective date May 94 May 99 Dec 96 Dec 96 Jan 99 Dec 96 Mar 96 Jun 98 Feb 97 May 98 USDA Certified X X X X X X X X X X USDA Process Verified Management Claims program for requirements Breed claim a—Lean color, texture, firmness, and overall skeletal characteristics, each must meet the requirements for the designated maturity, or younger b—A yield grade of 3.9 or lower, except carcasses evaluated after removal of all or part of the kidney, pelvic, and heart fat may not have a yield grade higher than 3.5 c—Moderately thick or thicker muscling and tend to be moderately wide and thick in relation to their length X—Indicates program requirement 1—Replaced Ada Angus Beef May 17, 2000

USDA Certified & Process Verified Programs

FIGURE 6-5 Standards ensure the production of consistent products. (Source: USDA)

Section One Introduction and Background

BEEF PROGRAMS

Quality Factors in Foods Chapter 6

TABLE II ALLOWANCES FOR DEFECTS IN RAISINS WITH SEEDS EXCEPT LAYER OR CLUSTER Defects

U.S. Grade A

U.S. Grade B

U.S. Grade C

Maximum count (per 32 ounces) Pieces of stem . . . . . . . . . . . . . . . . . . . . . . . . . .

1

2

3

Maximum count (per 16 ounces) Capstems in other than uncapstemmed types . . . .

10

15

20

Seeds in seeded types . . . . . . . . . . . . . . . . . . . . .

12

15

20

Loose capstems in uncapstemmed types . . . . . . .

20

20

20

Maximum (percent by weight) Sugar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

10

15

Discolored, damaged, or moldy raisins . . . . . . . . .

5

7

9

Damaged . . . . . . . . . . . . . . . . . . .

3

4

5

Moldy . . . . . . . . . . . . . . . . . . . . . .

2

3

4

Substandard Development and Undeveloped . . . .

2

5

8

Provided these limits are not exceeded:

Appearance or edibility of product: Slightly discolored or damaged by fermentation or any other defect not described above . . . . . . . . . .

Grit, sand, or silt . . . . . . . . . . . . . . . . . . . . . . . . .

May not be affected.

May not be more than slightly affected.

None of any consequence may be present that affects the appearance or edibility of the product.

FIGURE 6-6 Agriculture Marketing Service of the USDA provides guidelines for grade standards. (Source: USDA, American Marketing Service)

May not be more than materially affected. Not more than a trace may be present that affects the appearance or edibility of the product.

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Table I.—Classification of Flavor Identification of flavor characteristics Cooked

U.S. extra grade

U.S. standard grade

Definite

Definite.

Feed

Slight

Definite.

Bitter

—

Slight.

Oxidized

—

Slight.

Scorched

—

Slight.

Stale

—

Slight.

Storage

—

Slight.

Table II.—Classification of Physical Appearance Identification of physical appearance characteristics

U.S. extra grade

U.S. standard grade

Dry product: Unnatural color ..................

None

Slight.

Lumps ................................

Slight pressure

Moderate pressure.

Visible dark particles .........

Practically free

Reasonably free.

Free

Reasonably free.

Reconstituted product: Grainy ................................

Table III.—Classification According to Laboratory Analysis Laboratory tests

U.S. extra grade

Bacterial estimate, SPC/gram.

50,000

100,000.

Coliform estimate/gram.

10

10.

Milkfat content, percent.

Not less than 26.0, but less than 40.0.

Not less than 26.0, but less than 40.0.

4.5

5.0.

Spray proc.

15.0

22.5.

Roller proc.

22.5

32.5.

Spray proc.

1.0

1.5.

Roller proc.

15.0

15.0.

Moisture content, percent.1

U.S. standard grade

Scorched particle content, mg:

FIGURE 6-7 Tables provided by USDA indicate differences between extra grade and standard grade. (Source: USDA)

Solubility index, ml:

1

Milk solids not fat basis.

Quality Factors in Foods Chapter 6

Certification services, which facilitate ordering and purchasing of products used by large-volume buyers, assure these buyers that the products they purchase will meet the of the contract—with respect to quality, processing, size, packaging, and delivery. ●

Fresh fruits, vegetables, and specialty crops

●

Processed fruits and vegetables

●

Milk and other dairy products

●

Livestock and meat

●

Poultry

●

Eggs

●

Cotton

●

Tobacco

Mission The U.S. Department of Agriculture’s Agricultural Marketing Service (AMS) facilitates the strategic marketing of agricultural products in domestic and international markets by grading, inspecting, and certifying the quality of these products in accordance with official USDA standards or contract specifications. U.S. Grade Standards are quality driven and provide a foundation for uniform grading of agricultural commodities nationwide. Uniform standards provide identification, measurement, and control of quality characteristics important to the marketing function. In addition, they provide a common language for marketing, a means of establishing the value or basis for prices, and a gauge of consumer acceptance. USDA Grade Standards also form the basis for quality certification services that buyers and sellers of agricultural products use in domestic and international contracting. AMS provides the following services upon request for a fee: ●

Quality standards for more than 200 agricultural commodities to help buyers and sellers trade on agreed-upon quality levels

●

Grading, inspection, quality assurance, and acceptance services to certify the grade or quality of products for buyers and sellers

●

Inspection of facilities involved in the processing of agricultural commodities

●

Assessment and registration of product and service quality management systems to established internationally recognized standards for some commodities

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A variety of quality management services for some commodities are based on the International Organization for Standardization’s audit-based quality assurance standards. These services are designed to provide additional and alternative approaches to ing compliance with voluntary standards or contractual requirements.

Food Quality Assurance The AMS Food Quality Assurance Staff manages the Federal food product description system, as well as associated quality assurance policies and procedures for food procured by federal agencies using appropriated funds. The Food Quality Assurance Staff works with agencies, research and development groups, and industry on food specification issues. This work leads to the development of Commercial Item Descriptions (CID) and quality assurance procedures that will better serve government needs.

Commercial Item Descriptions In cooperation with industry, AMS develops and maintains commercial item descriptions (CIDs) for hundreds of food items. A CID is a simplified product description that concisely describes key product characteristics of an available, acceptable, commercial product. These CIDs are based on attributes that describe the odor, flavor, color, texture, analytical requirements, and so on, for each product (see Figure 6-8). The product areas include: ●

Meat, poultry, fish, and shellfish

●

Dairy foods and eggs

●

Fruit, juices, nectars, and vegetables

●

Bakery and cereal products

●

Confectionery, nuts, and sugar

●

Jams, jellies, nectars, and preserves

●

Bouillions and soups

●

Dietary foods and food specialty preparations

●

Fats and oils

●

Condiments and related products

●

Coffee, tea, and cocoa

●

Beverages, nonalcoholic

●

Composite food packages

Quality Factors in Foods Chapter 6

COMMERCIAL ITEM DESCRIPTION CHICKEN NUGGETS, FINGERS, STRIPS, FRITTERS, AND PATTIES, FULLY COOKED, INDIVIDUALLY FROZEN The U.S. Department of Agriculture (USDA) has authorized the use of this Commercial Item Description. 1. SCOPE 1.1 This Commercial Item Description (CID) covers individually frozen, fully cooked, solid muscle, chunked and formed or ground/chopped and formed, breaded or unbreaded, seasoned or unseasoned, chicken nuggets, fingers, strips, fritters, and patties (chicken products) packed in commercially acceptable containers, suitable for use by Federal, State, local governments, and other interested parties. 2. CLASSIFICATION 2.1 The frozen, fully cooked chicken products shall conform to the classifications in the following list and shall comply with USDA, Food Safety and Inspection Service (FSIS), Meat and Poultry Inspection Regulations, (9 CFR Part 381) and applicable State regulations. When applicable, the frozen, fully cooked chicken products shall comply with the USDA, Food and Nutrition Service (FNS), Child Nutrition Programs, National School Lunch Program

QUALITY CONTROL Regardless of government, research, or trade standards, most food manufacturing plants have some type of internal, formal, quality control or quality assurance department. These departments perform a wide variety of functions to ensure that a consistent, quality product is produced. Quality control may perform inspection duties, laboratory tests, oversee sanitation and microbiological aspects, and guide research and development. Total Quality Management (TQM) and Hazard Analysis and Critical Control Point (HAC) are two newer ideas for controlling quality and safety. TQM seeks to continuously improve the quality of products by making small changes in ingredients, manufacturing, handling, or storage, resulting in an overall improvement. All workers at a plant are involved in and responsible for the quality improvements in a product. HAC is a preventative food safety system. First a step-by-step analysis of the process for manufacturing, storing, and distributing a food product is conducted. Then tight control of the process is established at potential problem points. Control measures are put in place before problems occur.

FIGURE 6-8 Numerous food items purchased by the government have commercial item descriptions to ensure uniform products. (Source: USDA)

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HOW TO READ A MARKET REPORT The following and definitions are frequently used in Fruit and Vegetable Market News reports: QUALITY includes size, color, shape, texture, cleanness, freedom from defects, and other more permanent physical properties of a product which can affect its market value. The following , when used in conjunction with “quality,” are interpreted as meaning: FINE: Better than good. Superior in appearance, color, and other quality factors.

FIGURE 6-9 Knowledge of government standards is necessary to read market reports. (Source: USDA)

GOOD: In general, stock which has a high degree of merchantability with a small percentage of defects. This term includes U.S. No. 1 stock, generally 85 percent U.S. No. 1 or better quality on some commodities, such as tomatoes. FAIR: Having a higher percentage of defects than “good.” From a quality

Good Manufacturing Practices (GMPs) are guidelines that a company uses to evaluate the design and construction of food processing plants and equipment. These standards require that all stainless steel and plastics used during the processing steps must meet food-grade specifications. Agencies such as the USDA and the FDA will help food companies select appropriate equipment. The GMPs also require that hygiene and food procedures must be met. These procedures include wearing white uniforms, hair-nets, disposable gloves, face masks, and other protective gear. Standards for cleaning and sanitizing practices in food processing plants and equipment are also outlined in the GMPs. The treatment of water to make it of drinkable quality, the filtering of air, and the treatment of food processing wastes are also addressed in the GMPs. The management of unavoidable pests in food processing plants and warehouses is also done to ensure that GMPs are used. In effect, the GMPs cover every aspect of the processing of food (see Figure 6-9). The FDA and the USDA use these guidelines when inspecting a plant to ensure that it is in compliance with the regulations set forth in the Federal Food, Drug, and Cosmetic Act. The FDA provides copies of the GMP regulations.

Summary Consumers expect certain qualities from their food. These include color, flavor, texture, and even size. When these are missing or

Quality Factors in Foods Chapter 6

different than expected, the food is rejected. Food science determines and uses methods to measure food-quality factors. These methods ensure a consistent, reliable product. Some evaluation methods use chemical and mechanical techniques. Others are completely human, such as taste s. The USDA-AMS establishes quality and grading standards. Also, in cooperation with industry, the AMS develops and maintains commercial item descriptions for hundreds of items. Within the food industry, methods such as HAC, TQM, and GMP monitor quality.

Review Questions Success in any career requires knowledge. Test your knowledge of this chapter by answering these questions or solving these problems. 1. List the three components of reflected light used to define colors. 2. Name one instrument used to measure texture. 3. Discuss what humans can taste and what they smell and how this forms food flavor. 4. Identify the following acronyms: AMS, HAC, TQM, GMP, CID. 5. Industry and ____________ develop and maintain CIDs. 6. List six factors that can influence the flavor of food. 7. Changes in the texture of food are often due to _______. 8. What qualities do consumers expect of their food? 9. The study of the science of the deformation of matter is called _______. 10. How do fats or lipids affect the texture of food?

Student Activities 1. Cut an apple or a potato and time how long it takes for browning to occur on the cut surface. 2. Make a list of foods you eat and describe their color. Discuss what would happen to your consumption if the food color was changed. 3. Leave a slice of bread on a plate for a couple of days. Describe the textural changes. 4. Conduct a taste test. This revolves around taste alone or taste and the appearance of the food. For example, find

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out how red color affects food choice, or compare the taste of a name brand product with a generic product. A taste test could also be designed around the preferred texture of a food. 5. Many charts are available that visually explain the government grading standards. Obtain one of these charts and display it. 6. Remove potato chips from their packaging and place them in a plastic bag exposed to light. Explain the changes after few days. 7. Visit the USDA/AMS Web site on the Internet and describe the quality standards for one of the product groups or find a CID for a food item. Report your findings to the class.

Resources Corriher, S. O. 1997. Cookwise: The hows and whys of successful cooking. New York: William Morrow and Company, Inc. Cremer, M. L. 1998. Quality food in quantity. Management and science. Berkeley, CA: McCutchan Publishing Corporation. Drummond, K. E. 1994. Nutrition for the food service professional, 2nd ed. New York: Van Nostrand Reinhold. Gardner, J. E., Ed. 1982. Reader’s digest. Eat better, live better. Pleasantville, NY: Reader’s Digest Association, Inc. McGee, H. 1997. On food and cooking. The science and lore of the kitchen. New York: Simon and Schuster Inc. Vaclavik, V. A., and E. W. Christina. 1999. Essentials of food science. Gaithersburg, MD: Aspen Publishers, Inc.

Internet Internet sites represent a vast resource of information. The URLs (uniform resource locator) for the World Wide Web sites can change. Using one of the search engines on the Internet such as Yahoo!, HotBot, AltaVista, Excite, Dogpile, About, or Google, find more information by searching for these words or phrases: HAC, Maillard reaction, rheology, phenolic compounds, taste s, pasteurization, quality food standards, quality grading, Food Quality Assurance, commercial items descriptions, quality control. Also, Table A-7 provides a listing of some useful Internet sites that can be used as a starting point.