Online Activity: Introduction To Food Science

1. Based on Figure 1, which of the following is the CORRECT total solid balance equation for the overall process?

0.12V + 0.20Y = 0.09W + 0.21Z

0.12V = 0.21Z

0.12V + 0.20Y = 0.09W

0.20Y = 0.09W + 0.21Z

The correct total solid balance equation for the overall process is 0.12V + 0.20Y = 0.09W + 0.21Z. This equation represents the balance of solid materials (V, Y, W, and Z) in the process, with the coefficients representing the quantities of each material.

Explanation

The correct total solid balance equation for the overall process is 0.12V + 0.20Y = 0.09W + 0.21Z. This equation represents the balance of solid materials (V, Y, W, and Z) in the process, with the coefficients representing the quantities of each material.

2. Banana puree is an example of flow behaviour of _________, whereby the viscosity decreases with increasing shear rate.

Shear thickening

Bingham plastic

Shear thinning

Thixotropic

Banana puree is an example of shear thinning flow behavior because its viscosity decreases with increasing shear rate. This means that as the puree is subjected to more force or agitation, such as when it is stirred or blended, it becomes less viscous and flows more easily. This is a common characteristic of many food products, where the viscosity decreases as they are subjected to shear forces.

Explanation

Banana puree is an example of shear thinning flow behavior because its viscosity decreases with increasing shear rate. This means that as the puree is subjected to more force or agitation, such as when it is stirred or blended, it becomes less viscous and flows more easily. This is a common characteristic of many food products, where the viscosity decreases as they are subjected to shear forces.

3. The D-value for Bacillus aureus is 5 minutes at 90^oC and the z-value is 7.5^oC. What is the D_97.5^o_C value for Bacillus aureus? Note: D-value is the time taken at a given temperature to kill 90% of the microorganisms in a sample. Z-value is the change in °C of processing temperature requires to cause a 10-fold change in D-value.

0.1 minutes

0.5 minutes

1 minute

5 minutes

The D-value for Bacillus aureus is the time taken at a given temperature to kill 90% of the microorganisms in a sample. The z-value is the change in temperature required to cause a 10-fold change in the D-value. In this case, the D-value is given as 5 minutes at 90°C and the z-value is given as 7.5°C. To find the D97.5°C value, we need to calculate the D-value at a temperature 7.5°C higher than 90°C. Since the z-value indicates a 10-fold change in the D-value, the D97.5°C value would be 10 times smaller than the D-value at 90°C, which is 0.5 minutes.

Explanation

The D-value for Bacillus aureus is the time taken at a given temperature to kill 90% of the microorganisms in a sample. The z-value is the change in temperature required to cause a 10-fold change in the D-value. In this case, the D-value is given as 5 minutes at 90°C and the z-value is given as 7.5°C. To find the D97.5°C value, we need to calculate the D-value at a temperature 7.5°C higher than 90°C. Since the z-value indicates a 10-fold change in the D-value, the D97.5°C value would be 10 times smaller than the D-value at 90°C, which is 0.5 minutes.

4. Gus cooked some chicken breast with carrots on a stove. The chicken breast was previously glazed with some honey. Which of the following chemical reactions will occur?i) Maillard reactionii) Starch gelatinizationiii) Enzymatic browningiv) Caramelization

I only

Ii and iii

I and iv

Ii, iii and iv

The Maillard reaction occurs when proteins and sugars are heated together, resulting in browning and the development of complex flavors. Since the chicken breast was glazed with honey, which contains sugars, the Maillard reaction is likely to occur. Caramelization, on the other hand, is the browning of sugars alone, so it is also likely to occur due to the presence of honey. Starch gelatinization and enzymatic browning are not relevant in this scenario, as they involve different reactions and ingredients.

Explanation

The Maillard reaction occurs when proteins and sugars are heated together, resulting in browning and the development of complex flavors. Since the chicken breast was glazed with honey, which contains sugars, the Maillard reaction is likely to occur. Caramelization, on the other hand, is the browning of sugars alone, so it is also likely to occur due to the presence of honey. Starch gelatinization and enzymatic browning are not relevant in this scenario, as they involve different reactions and ingredients.

5. Who invented the method of sterilizing food in glass jars?

Alexander Fleming

Louis Pasteur

Napoleon Bonaparte

Nicolas Appert

Nicolas Appert invented the method of sterilizing food in glass jars. This method, known as canning, involves sealing food in airtight containers and heating them to kill bacteria and other microorganisms, preserving the food for long periods of time. Appert's invention revolutionized the food preservation industry and has since become a widely used method around the world.

Explanation

Nicolas Appert invented the method of sterilizing food in glass jars. This method, known as canning, involves sealing food in airtight containers and heating them to kill bacteria and other microorganisms, preserving the food for long periods of time. Appert's invention revolutionized the food preservation industry and has since become a widely used method around the world.

6. Disaccharides are sugars made by linking two monosaccharides. Which of the following disaccharide has the INCORRECT components?

Maltose = glucose + fructose

Lactose = galactose + glucose

Sucrose = glucose + fructose

Trehalose = glucose + glucose

Maltose is a disaccharide made up of two glucose molecules, not glucose and fructose.

Explanation

Maltose is a disaccharide made up of two glucose molecules, not glucose and fructose.

7. A food solution was processed through unit operations 1 and 2, as shown in Figure 1. Which of the following overall mass balance equation best represents the process below?

W = V + Y + Z

W + Y = Z

V + Y = W + Z

V = W + Z

The given mass balance equation V + Y = W + Z represents the process described in the question. This equation states that the sum of the inputs (V and Y) is equal to the sum of the outputs (W and Z). Therefore, it accurately represents the overall mass balance of the process.

Explanation

The given mass balance equation V + Y = W + Z represents the process described in the question. This equation states that the sum of the inputs (V and Y) is equal to the sum of the outputs (W and Z). Therefore, it accurately represents the overall mass balance of the process.

8. Freezing is a food preservation technique that is able to retain most nutrient content and ___________ the water activity in food.

Lower

Increase

Maintain

Made disappear

Freezing is a food preservation technique that is able to retain most nutrient content and lower the water activity in food. When food is frozen, the water molecules in it turn into ice crystals, reducing the availability of water for microbial growth and enzymatic reactions. This helps to slow down the spoilage process and preserve the nutrients present in the food. Lowering the water activity also helps to maintain the texture and quality of the frozen food.

Explanation

Freezing is a food preservation technique that is able to retain most nutrient content and lower the water activity in food. When food is frozen, the water molecules in it turn into ice crystals, reducing the availability of water for microbial growth and enzymatic reactions. This helps to slow down the spoilage process and preserve the nutrients present in the food. Lowering the water activity also helps to maintain the texture and quality of the frozen food.

9. Amylose is a linear chain polymer composed of glucose residues in α (1→4) linkages and it is used as energy storage in starch.

True

False

Amylose is indeed a linear chain polymer composed of glucose residues in α (1→4) linkages. It is one of the two components of starch, the other being amylopectin. Amylose is used as a form of energy storage in plants, where it is found in the form of granules. It is a polysaccharide that can be broken down by enzymes called amylases to release glucose molecules for energy. Therefore, the statement "Amylose is a linear chain polymer composed of glucose residues in α (1→4) linkages and it is used as energy storage in starch" is true.

Explanation

Amylose is indeed a linear chain polymer composed of glucose residues in α (1→4) linkages. It is one of the two components of starch, the other being amylopectin. Amylose is used as a form of energy storage in plants, where it is found in the form of granules. It is a polysaccharide that can be broken down by enzymes called amylases to release glucose molecules for energy. Therefore, the statement "Amylose is a linear chain polymer composed of glucose residues in α (1→4) linkages and it is used as energy storage in starch" is true.

10. ______________ has been used to preserve foods for astronauts and backpackers. These foods have better taste, texture, appearance and porous structure.

Vacuum drying

Freezing

Pasteurization

Freeze drying

Freeze drying has been used to preserve foods for astronauts and backpackers. Freeze drying involves removing the moisture from the food by freezing it and then placing it in a vacuum, where the ice crystals sublimate directly from solid to gas, without going through the liquid phase. This process helps to retain the taste, texture, appearance, and porous structure of the food, making it an ideal preservation method for long-duration space missions and outdoor activities.

Explanation

Freeze drying has been used to preserve foods for astronauts and backpackers. Freeze drying involves removing the moisture from the food by freezing it and then placing it in a vacuum, where the ice crystals sublimate directly from solid to gas, without going through the liquid phase. This process helps to retain the taste, texture, appearance, and porous structure of the food, making it an ideal preservation method for long-duration space missions and outdoor activities.

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