Food Science Final Exam

FCS-FS-3 c. Define and differentiate between chemical and physical changes in food.

Yeast plays a role in fermentation by acetic-acid bacteria. Yeast is a type of microorganism that is commonly used in fermentation processes, such as the production of alcoholic beverages and bread. In the case of acetic-acid bacteria, yeast is responsible for converting sugars into alcohol through the process of fermentation. This alcohol is then further metabolized by the acetic-acid bacteria to produce acetic acid, which gives vinegar its distinct sour taste. Therefore, yeast is an essential component in the fermentation process carried out by acetic-acid bacteria.

Pasteurization is the process of heating food or beverages to a specific temperature for a certain period of time to kill harmful bacteria and extend their shelf life. This scientific discovery is closely linked to controlling fermentation in food because it helps to prevent the growth of microorganisms that can cause spoilage and fermentation. By heating the food, pasteurization can destroy or inactivate the enzymes and microorganisms responsible for fermentation, thus preserving the quality and safety of the food product.

Titration is a procedure used to determine the molarity or concentration of a solution. It involves adding a known solution of one substance (the titrant) to a known volume of another solution (the analyte) until a reaction between the two is complete. By measuring the volume of titrant required to reach the endpoint of the reaction, the molarity of the analyte solution can be calculated. This method is commonly used in chemistry laboratories to determine the concentration of acids, bases, or other substances in a solution.

Ionization refers to the process in which water molecules separate into hydrogen and hydroxide ions. This process occurs in only a small percentage of water molecules.

FCS-FS 2 a. Identify physical, physicochemical, and chemical techniques used for assessing food quality.

FCS-FS-4 a. Explain how heat is transferred in the cooking, baking, and thermal preservation processes and demonstrate the methods of boiling, roasting, and microwaving.

The correct answer is "All of the above." This means that all of the statements provided in the options are true when comparing taste buds to olfactory organs. Taste buds respond to particles dissolved in liquid, while olfactory organs respond to particles dissolved in air. Taste buds detect a few basic tastes, while olfactory organs can recognize many different odors. Additionally, olfactory organs perceive sensations more rapidly than taste buds do. Therefore, all three statements correctly differentiate taste buds from olfactory organs.

Water-soluble vitamins, such as vitamin C and the B-complex vitamins, dissolve in water and are easily transported throughout the body. These vitamins cannot be stored in large amounts and are not stored in the body for long periods of time, so they need to be replenished daily through diet or supplements. Unlike fat-soluble vitamins, water-soluble vitamins are not stored in fatty tissues and any excess amounts are excreted through urine.

On the pH scale, lower values indicate greater acidity. The pH scale measures the acidity or alkalinity of a substance, with values ranging from 0 to 14. A pH value below 7 is considered acidic, and as the value decreases, the acidity increases. Therefore, lower values on the pH scale indicate greater acidity.

To do a titration of an acid solution, it is necessary to know the volume of the acid solution, the volume of a basic solution, and the concentration of the basic solution. The volume of the acid solution is important to determine the stoichiometry of the reaction and calculate the amount of acid present. The volume of the basic solution is needed to determine the equivalence point of the reaction. Lastly, the concentration of the basic solution is essential to calculate the molarity of the acid solution. Therefore, all the given statements are true for a successful titration of an acid solution.

FCS-FS-3 e. Compare and contrast elements and compounds and explain the difference between ionic and covalent bonds and compounds.

FCS-FS-4 b. Compare the effect of various temperatures on rates of chemical and physical reactions.

The melting point refers to the temperature at which a substance transitions from a solid to a liquid state. At this temperature, the substance has absorbed enough energy to break the bonds holding its particles together in a solid structure, allowing them to move freely and take on the characteristics of a liquid.

A colloidal dispersion is a mixture where particles are evenly distributed but do not dissolve. In this type of mixture, the particles are suspended in a medium and can be seen under a microscope. The particles are larger than those in a solution but smaller than in a suspension. This allows for a stable dispersion where the particles do not settle out over time.

Surface tension is the result of water molecules' strong attraction for each other. This attraction causes the molecules at the surface of the water to be more strongly attracted to each other than to the air or another substance. This creates a "skin-like" effect, where the surface of the water acts as if it has a thin, elastic film. This property allows certain insects to walk on water and allows small objects, like paper clips, to float on the surface.

Fermentation is most useful for someone serving cheese chunks and sausage slices because fermentation can enhance the flavors and textures of both cheese and sausage. Fermentation can help break down the proteins in cheese, resulting in a more complex and flavorful product. It can also add tanginess and depth to sausage, making it more delicious. Therefore, using fermented cheese and sausage can elevate the taste experience of this appetizer combination.

A base is a substance that releases hydroxide ions in solution. This means that when the base is dissolved in water, it will dissociate and release hydroxide ions (OH-) into the solution. Bases are known for their ability to neutralize acids and have a pH value greater than 7. They can also react with acids to form water and a salt. Examples of bases include sodium hydroxide (NaOH) and calcium hydroxide (Ca(OH)2).

A polar molecule is formed when there is an unequal distribution of electron density between the atoms in a molecule. In this case, the covalently bonded atoms are arranged in such a way that there is a clear division of positive and negative charges within the molecule. This creates a dipole moment, with one end of the molecule being more positive and the other end being more negative. The presence of this dipole moment makes the molecule polar.

Osteomalacia is a vitamin D deficiency disease in adults that leads to the deformation of bones. Vitamin D is essential for the absorption of calcium and phosphorus, which are necessary for bone health. When there is a deficiency of vitamin D, the body is unable to properly mineralize the bones, resulting in weakened and misshapen bones. Perricious anemia, pellagra, and beriberi are not related to bone deformities, making osteomalacia the correct answer.

A buffer is a substance that helps maintain the pH of a solution by resisting changes in acidity or alkalinity. It can prevent the blood from becoming too acidic or basic by absorbing or releasing hydrogen ions (H+) to maintain a stable pH level. Buffers are important in biological systems as they help regulate the pH and ensure that essential biological processes can occur within a narrow pH range.

A physical property refers to a characteristic of a substance that can be observed or measured without altering the substance's chemical composition. This means that the substance remains the same even when its physical properties are measured or observed. Examples of physical properties include color, density, melting point, and conductivity.

A colloidal dispersion refers to a mixture in which particles are evenly distributed but do not dissolve. In a colloidal dispersion, the particles are larger than those in a solution but smaller than those in a suspension. These particles remain suspended in the medium due to the balance between attractive and repulsive forces. This type of mixture can be seen in substances like milk, fog, or gelatin, where particles are dispersed throughout the medium but do not dissolve.

The correct answer is "heat of vaporization" because it refers to the amount of energy required for a substance to change from a liquid to a gas at its boiling point. This process involves breaking intermolecular forces and converting the substance's state of matter, resulting in the absorption of heat energy. The heat of vaporization is specific to each substance and is typically measured in joules per gram (J/g).

When water is boiled, it reaches a high temperature which leads to the destruction of nutrients present in the water. This happens because water's properties as a solvent allow it to dissolve and carry away different substances, including nutrients. Therefore, the destruction of nutrients through boiling highlights the problem associated with water's properties as a solvent.

An emulsion is a mixture of two immiscible substances, in this case, a liquid portion and chicken fat portion. Emulsions are stabilized by the addition of an emulsifier, which helps to prevent the separation of the two substances. Therefore, the chemical name for a gravy that separates into a liquid portion and chicken fat portion would be an emulsion.

Larger crystals do not produce a smoother candy. In fact, smaller crystals produce a smoother texture in candy making. When the syrup cools and crystallizes, smaller crystals form, resulting in a smoother texture. Larger crystals can make the candy feel gritty or grainy in the mouth. Therefore, the statement "larger crystals produce a smoother candy" is not true.

An indicator is a substance that can be used to determine the pH of a solution by changing color. When an indicator is added to a solution, it reacts with the hydrogen ions (H+) or hydroxide ions (OH-) present, causing a color change that can be used to determine the acidity or alkalinity of the solution. This property makes indicators useful in various applications, such as in chemistry experiments, medical tests, and quality control processes.

Heterogeneous mixtures consist of individual substances that are dissimilar and can be recognized by sight. In these mixtures, the different components are not evenly distributed and can be easily distinguished from one another. This is in contrast to homogeneous mixtures, where the components are uniformly distributed and cannot be visually distinguished. Elements and compounds, on the other hand, are pure substances and not mixtures.

Boiling is not helpful in making sauerkraut because it can destroy the beneficial bacteria that are responsible for the fermentation process. Fermentation is the key step in making sauerkraut, where the cabbage is salted and left to ferment naturally. Boiling would kill these bacteria and prevent the fermentation process from occurring. Therefore, boiling is not a helpful step in making sauerkraut.

FCS-FS-4 b. Compare the effect of various temperatures on rates of chemical and physical reactions.

Pellagra is a niacin deficiency disease that is characterized by symptoms such as diarrhea and dermatitis. If left untreated, it can progress to more severe conditions like dementia and even death. Therefore, pellagra is the correct answer for the given description. Night blindness is caused by a deficiency in vitamin A, scurvy is caused by a deficiency in vitamin C, and beriberi is caused by a deficiency in thiamine (vitamin B1). These conditions do not match the symptoms described in the question.

Beta carotene is an orange plant pigment that can be converted into vitamin A in the intestines and liver. This conversion occurs through a process called enzymatic cleavage, where beta carotene is broken down into retinol, the active form of vitamin A. This conversion is important because vitamin A plays a crucial role in various bodily functions, including vision, immune function, and cell growth. Therefore, consuming foods rich in beta carotene, such as carrots, sweet potatoes, and spinach, can help ensure an adequate intake of vitamin A.

A pH meter is the most reliable way to find a pH level because it directly measures the concentration of hydrogen ions in a solution. It provides a precise and accurate reading, allowing for more precise adjustments and control of pH levels. Litmus paper can only provide a rough estimate and is less accurate. Anthocyanins are pigments found in plants and have no direct relation to measuring pH levels. A pH scale is a reference tool that helps in understanding pH levels but does not provide an actual measurement.

Molarity is a measurement that indicates the moles of solute per liter of solution. It is a unit of concentration commonly used in chemistry to express the amount of solute dissolved in a given amount of solvent. Molarity is calculated by dividing the number of moles of solute by the volume of the solution in liters. It is an important concept in many chemical calculations and is used to determine the amount of reactants required in a chemical reaction or to calculate the concentration of a solution.

FCS-FS-3. Students will discuss the basic chemistry concepts of food science.
b. Describe solutions, heterogeneous mixtures, and homogeneous mixtures and explain their similarities and differences.

As you add solute to a solution, the amount of solute particles increases in relation to the solvent. This leads to a higher concentration of solute in the solution, making it more concentrated. Therefore, the correct answer is "concentrated".

FCS-FS-3 b. Describe solutions, heterogeneous mixtures, and homogeneous mixtures and explain their similarities and differences.

The properties of a simple sugar are determined by how atoms are arranged in its molecules. The arrangement of atoms affects the sugar's chemical and physical properties, such as its solubility, taste, and reactivity. Different arrangements can result in sugars with different properties, even if they have the same chemical formula.

Fats in foods are not generally easy to identify because they can be hidden in various forms, such as invisible fats in processed foods or cooking oils used in preparation. It can be challenging to determine the fat content of a food item without reading labels or having specific knowledge about the ingredients used.

Latent heat refers to the energy that a substance either uses or releases when it undergoes a phase change, such as from solid to liquid or liquid to gas. It is the heat energy absorbed or released during these phase transitions without a change in temperature. This term is used to describe the amount of energy required to break the intermolecular forces holding the particles together in a solid or liquid, or the energy released when these forces are formed during condensation or solidification.

Osteomalacia is a vitamin D deficiency disease in adults that leads to the softening and misshaping of bones. This condition occurs due to a lack of vitamin D, which is essential for the absorption of calcium and phosphorus in the body. Without sufficient levels of these minerals, the bones become weak and prone to fractures. Osteomalacia is different from rickets, which is a similar condition that affects children. Provitamination and scurvy are unrelated to vitamin D deficiency and do not cause soft and misshapened bones.

An acid is a substance that releases hydrogen ions in a solution. This means that when an acid is dissolved in water, it donates hydrogen ions (H+) to the solution. These hydrogen ions make the solution more acidic. Acids have a pH value less than 7 and can react with bases to form salts and water.

The description "5 g of sodium per liter" refers to the concentration. Concentration is a measure of the amount of a substance dissolved in a given volume of solution. In this case, it is indicating that there are 5 grams of sodium dissolved in each liter of solution.

FCS-FS-12 d. Discuss factors affecting a person’s food preference such as physical, psychological, cultural, and environmental influences.

Texture is the combined effect of mouthfeel and sound. Mouthfeel refers to the physical sensations experienced in the mouth when consuming food or drink, such as the smoothness, creaminess, or thickness. Sound, on the other hand, refers to the auditory cues produced when consuming certain foods, such as the crunchiness of a chip or the sizzle of frying. Together, these two factors contribute to the overall perception of texture in food.

Acids in foods pose little health risk because they are weak. Weak acids do not ionize completely in water, which means they release fewer hydrogen ions and have a lower acidity level. This lower acidity level makes them less harmful to the body when consumed in moderate amounts. Strong acids, on the other hand, can cause tissue damage and other health issues if ingested. Therefore, the fact that the acids in foods are weak helps to ensure that they do not pose a significant health risk.

FCS-FS b. Define sensory evaluation, identify the qualities that make-up the sensory characteristics of food, and explain how taste, aroma and mouth sensations combine to give food their flavor.

Heat of fusion refers to the energy used and released when a substance changes between its solid and liquid phases. It is the amount of heat required to convert a unit mass of a substance from a solid to a liquid at its melting point, or vice versa. This process involves the breaking or formation of intermolecular bonds, resulting in either absorption or release of energy. Therefore, the correct answer is heat of fusion.

The hydrogen bonds in water create a polar molecule. Water is a polar molecule because the oxygen atom is more electronegative than the hydrogen atoms, causing the electrons to spend more time near the oxygen atom. This creates a partial negative charge on the oxygen atom and partial positive charges on the hydrogen atoms. The polarity of water allows it to form hydrogen bonds with other water molecules and other polar molecules, giving it unique properties such as high surface tension, the ability to dissolve many substances, and a high boiling point.

Beriberi is a thiamin deficiency disease that is characterized by symptoms such as weakness, loss of appetite, irritability, poor arm and leg coordination, and a tingling sensation throughout the body. This condition is caused by a lack of thiamin (vitamin B1) in the diet, which is essential for the proper functioning of the nervous system and energy production.

The statement "A fat gives best results when it reaches its smoke point" is not true of fats in frying. When a fat reaches its smoke point, it begins to break down and release smoke, indicating that it is being oxidized and can potentially create harmful compounds. It is generally recommended to avoid heating fats beyond their smoke point to maintain their quality and avoid the production of smoke and off-flavors in the food being fried.

When a base is dissolved in a solution, it produces hydroxide ions (OH-). These hydroxide ions then react with hydrogen ions (H+) present in the solution, leading to the formation of water molecules. This process is known as neutralization, where the base neutralizes the solution by balancing the pH. Therefore, the correct answer is that a base in solution produces hydroxide ions.

A basic, 2 M solution could be used to carry out the titration of a solution of unknown acidity. Titration is a technique used in chemistry to determine the concentration of an unknown solution by reacting it with a solution of known concentration (in this case, a basic 2 M solution). By carefully measuring the volume of the known solution required to neutralize the unknown solution, the acidity or alkalinity of the unknown solution can be determined.

The boiling point is the temperature at which liquid water exerts an upward pressure equal to the downward pressure. At this temperature, the vapor pressure of the liquid equals the atmospheric pressure, causing the liquid to rapidly convert into vapor or gas. This process is known as boiling.

The effects of diabetes illustrate the importance of glucose to the body. Diabetes is a condition characterized by high blood sugar levels, indicating a problem with the body's ability to regulate glucose. This highlights the crucial role that glucose plays in the body's functioning and the detrimental effects that occur when this regulation is disrupted.

A base in which few molecules ionize is called weak because it does not fully dissociate into ions in solution. This means that only a small fraction of the base molecules break apart into ions, resulting in a lower concentration of ions in the solution compared to a strong base.

When a solution reaches its "equivalence" point, it means that the base and acid in the solution have contributed an equal number of ions. This indicates that the reaction between the base and acid is complete and the solution is neutralized. The term "equivalence" refers to the point at which the reactants have been consumed in stoichiometric amounts, resulting in a balanced chemical equation. This is commonly observed in titration experiments, where a known concentration of one solution is gradually added to another until the equivalence point is reached.

Hydrolysis is important to physical health because it reduces carbohydrates to glucose. This process breaks down complex carbohydrates into simpler molecules, specifically glucose, which is the primary source of energy for the body. By converting carbohydrates into glucose, hydrolysis ensures that the body can efficiently utilize this energy source for various bodily functions and maintain optimal physical health.

The equivalence point is the stage of titration where the amount of acid and base being reacted is stoichiometrically equivalent. At this point, all the hydrogen ions from the acid have been neutralized by the hydroxide ions from the base, resulting in the formation of water. Therefore, the equivalence point indicates neutralization.

FCS-FS 2 c. Explain what sensory evaluation panels do and conduct a sensory panel using appropriate controls; quantify and analyze the data.

The correct answer is stating that the girl is mistaken in thinking that she can get excessive doses of Vitamin A from food alone. The answer implies that the girl's belief is incorrect and that she can only get excessive doses of Vitamin A from supplements, not from food.

When two moles of solute are dissolved in one liter of solvent, the resulting solution has a molarity of 2.0. Molarity is a measure of the concentration of a solution and is defined as the number of moles of solute per liter of solvent. In this case, since two moles of solute are dissolved in one liter of solvent, the molarity is 2.0.

Water helps regulate body temperature through its high heat of vaporization. When the body gets too hot, sweat glands release water onto the skin. As this sweat evaporates, it takes heat energy from the body, cooling it down. This process is possible due to water's high heat of vaporization, which means it requires a significant amount of heat energy to convert water from a liquid to a gas.

Erythrocyte hemolysis is the correct answer because it refers to the condition of broken red blood cells, which is a characteristic of the vitamin E deficiency condition described in the question. This condition is sometimes seen in premature babies and can lead to weakness and listlessness.

Concentration is the correct answer because it refers to the measurement of the amount of a substance per unit of volume. It is a quantitative measure that indicates how much of a solute is dissolved in a solvent. Concentration can be expressed in various units such as molarity, percent by volume, or parts per million. It is an important concept in chemistry and is used to determine the strength or dilution of a solution.

Sublimation refers to the direct change of a substance from solid to gas without going through the liquid phase. This process occurs when the substance's vapor pressure exceeds its surrounding pressure, causing it to bypass the liquid phase and directly convert into a gas. This phenomenon is commonly observed in substances such as dry ice (solid carbon dioxide) and mothballs (naphthalene).

Hard water does not result from water's effectiveness as a dispersing medium. Hard water is caused by the presence of high levels of minerals, such as calcium and magnesium, in the water. These minerals can accumulate and cause scale buildup in pipes and appliances. The effectiveness of water as a dispersing medium refers to its ability to dissolve and disperse substances, but it is not directly related to the hardness of water.

When a hydrogen ion (H+) and a hydroxide ion (OH-) bond together, they form water (H2O). This reaction is known as neutralization, where an acid and a base react to produce a neutral substance. In this case, the hydrogen ion is from the acid and the hydroxide ion is from the base, and their combination results in the formation of water, which is a neutral substance. Therefore, the correct answer is water.

FCS-FS-3e. Compare and contrast elements and compounds and explain the difference between ionic and covalent bonds and compounds.

Proteolytic bacteria play a crucial role in the fermentation process of chocolate cakes and candy bars. These bacteria break down proteins into smaller peptides and amino acids, which contribute to the development of flavors and textures in the final products. Without the activity of proteolytic bacteria, the cakes and candy bars would lack the complex and enjoyable taste that fermentation brings.

Supersaturated sugar solutions are possible because sugar is more soluble in a hotter solute. When a solute, such as sugar, is dissolved in a solvent, such as water, the solute particles break apart and mix with the solvent particles. The solubility of a solute refers to how much of it can dissolve in a given amount of solvent at a specific temperature. In the case of sugar, it is more soluble in a hotter solute because the increased temperature increases the kinetic energy of the solvent particles, allowing them to move more rapidly and break apart the sugar particles more effectively. This results in a higher concentration of dissolved sugar in the solution, creating a supersaturated sugar solution.

Neutralization is the correct answer because it refers to a chemical reaction that occurs when an acid and a base react to form water and a salt. In this reaction, the acidic and basic properties of the reactants are neutralized, resulting in the formation of a neutral product. This process is commonly used in various applications, such as in the treatment of acidic wastewater or in the preparation of neutral solutions for laboratory experiments.

Water acts as a medium for vital chemical reactions because it provides a suitable environment for these reactions to occur. It has unique properties such as its ability to dissolve many substances, its high heat capacity, and its role as a solvent. These properties allow water to facilitate the movement of molecules and ions, making it an ideal medium for chemical reactions to take place.

The term "strength" refers to the extent or degree of acidity or basicity of a solution. In the context of acids and bases, it describes the percentage of molecules that dissociate into ions when dissolved in water. A strong acid or base is one that completely ionizes, meaning a high percentage of its molecules form ions in solution.

FCS-FS 2 e. Describe the role of science in the development of new food products and the use of the scientific method.

Fried foods, such as onion rings, are more likely to become rancid compared to other options listed. This is because frying in oil introduces oxygen to the food, which can lead to oxidation and the development of rancidity. Additionally, the high fat content in fried foods provides an ideal environment for the oxidation process to occur.

Indigenous bacteria are welcome on a head of cabbage that is destined to become sauerkraut because they play a crucial role in the fermentation process. These bacteria are naturally present on the cabbage and help to convert the sugars in the cabbage into lactic acid, which gives sauerkraut its distinctive tangy flavor. The presence of indigenous bacteria ensures that the fermentation process occurs properly and results in the desired flavor and texture of sauerkraut.

Proteins in the body serve various functions, including forming the main substance in hormones, building replacement cells, and balancing pH levels. However, they do not directly supply lasting energy. While proteins can be broken down into amino acids, which can be used as an energy source, their primary role is not to provide energy but rather to support growth, repair, and maintenance of the body's tissues and organs.

Neutralization is a chemical reaction that occurs when an acid and a base react to form a salt and water. Water is always produced as a result of this reaction. Therefore, the presence of water indicates that neutralization has occurred.

Fats in the body do not primarily serve the function of providing immediate energy. While fats can be used as a source of energy, carbohydrates are the body's preferred and most efficient source of immediate energy. Fats are mainly stored and utilized for long-term energy storage, insulation, cushioning internal organs, transporting vitamins, and promoting a constant body temperature.

Lowering air pressure reduces the resistance water must overcome to boil. When the air pressure is lower, the boiling point of water decreases, meaning that it requires less energy for the water molecules to break free from the liquid phase and turn into vapor. This is because at lower air pressure, there are fewer air molecules pushing down on the surface of the water, making it easier for the water molecules to escape into the gas phase. Therefore, reducing the resistance water must overcome to boil is the correct explanation for how lowering air pressure affects water's boiling point.

The basic difference between the fermentation of coffee cherries and tea leaves is that coffee fermentation uses bacteria, while tea fermentation does not. This means that during the fermentation process of coffee cherries, bacteria are involved in breaking down the sugars and converting them into acids, which affects the flavor of the coffee. In contrast, tea leaves undergo a process called oxidation, where the enzymes present in the leaves react with oxygen, resulting in chemical changes that give tea its characteristic flavor.

Denaturation is the process that must precede coagulation. This means that denaturation occurs before coagulation takes place. Denaturation refers to the unfolding or disruption of the structure of a protein, which is necessary for coagulation to occur. Coagulation, on the other hand, involves the formation of insoluble clumps or aggregates of proteins. Therefore, denaturation is a prerequisite for coagulation to happen.

Over time, the protein in eggs undergoes a process called "break down". This means that the protein molecules in the eggs gradually decompose or degrade, resulting in a loss of their structural integrity and functionality. This breakdown can be caused by various factors such as heat, enzymes, and chemical reactions. As a result, the eggs become less firm and lose their original texture and consistency.