This set of Fruits Processing Multiple Choice Questions & Answers (MCQs) focuses on “Fruit Juice Technologies”.
1. How are fruit juices preserved?
a) Spray drying
b) Canning
c) Freezing
d) Spray drying, canning, freezing
View Answer
Explanation: Juice is prepared by mechanically squeezing or macerating fruit flesh. It is done without the application of heat or solvents. Common methods for preservation and processing of fruit juices include canning, pasteurization, concentrating, freezing, evaporation and spray drying.
2. What is macerating?
a) Soaking the fruit in sugar solution
b) Soaking the fruit in salt solution
c) Coating the fruit with sugar
d) Coating the fruit with salt
View Answer
Explanation: The process of soaking fruit in liquid and sugar is called maceration. It softens and releases its juices. Macerating is similar to marinating the fruits. It absorbs the flavors of the liquid as they soak and soften.
3. What factor affects the juice yield?
a) Type of the pressing device
b) Flexible filter
c) Rigid filter
d) Type of washing chemicals
View Answer
Explanation: Juice yield is basically determined by the type of the pressing device, and the quality. It also depends on the preparation of the raw material. The most important parameter of pressing is the liquid yield, which means the percentage of juice extracted, compared to the raw material at the beginning of the process.
4. What is marc?
a) Remaining material in the equipment after pressing
b) Remaining material in the equipment after boiling
c) Remaining material in the equipment after drying
d) Remaining material in the equipment after freezing
View Answer
Explanation: Pressing separates a food system into two phases. The fruit tissues mean the solid phase, while the liquid between the particles is the liquid phase. Pressing needs outside forces to create tension in the system, drain liquid, resulting in shape modification. The remaining material, with low liquid content, is called marc.
5. What is the ideal temperature for diffusion fluid extraction?
a) 150–170°C
b) 50–70°C
c) 20–40°C
d) 80–100°C
View Answer
Explanation: Diffusion fluid extraction is done by making the semi permeable cell walls into permeable. Then following a heat treatment where the cell fluid is then dissolved with water. In order to increase the diffusion coefficient and the permeability of the cell walls, diffusion fluid extraction is performed at 50–70°C.
6. What is mechanical expression?
a) It is a unit operation in juice processing
b) It is a verbal usage in food industry
c) It is a boiling unit
d) It is freezing unit
View Answer
Explanation: Mechanical expression is the unit operation in juice processing. It is the separation technique where the liquids are separated from solids by the application of compressive forces. It is commonly used in the food and beverage industries.
7. Which of the following is used in extraction of juice from sugar cane?
a) Hydraulic pressing
b) Roller pressing
c) Screw pressing
d) Hydraulic pressing, roller pressing, screw pressing
View Answer
Explanation: The roller presses are used for energy-efficient grinding of large product quantities. The two rollers rotate in opposite directions. This exerts very high pressure on the material which effectively crushes and weakens the particles.
8. Which of the following presses is used as finisher for producing thick pulps?
a) Hydraulic pressing
b) Roller pressing
c) Screw pressing
d) Plate pressing
View Answer
Explanation: Hydraulic presses are widely used in fruit juice processing. Roller presses are used the production of sugar cane juice. Screw presses are tends to be used as finisher which follows a previous pulp thickening process by means of other thickening techniques.
9. Which of the following presses is called as expeller?
a) Hydraulic pressing
b) Roller pressing
c) Screw pressing
d) Plate pressing
View Answer
Explanation: Screw press is called as expeller. The fruit pulps are fed to a thick walled cylinder containing a rotating polished screw having a gradually decreasing pit. Material trapped between the screw and the inside of the cylinder barrel passes through a gradually reducing flow area, with increasing compressive force.
10. The viscosity of the liquid extracted affects the efficiency of the mechanical expression process.
a) True
b) False
View Answer
Explanation: The efficiency of an expression process depends on several factors. They are the yield stress of the solid phase and its resistance to deformation. The porosity of the cake formed and the viscosity of the liquid extracted also affects the quality.
11. Preparation with heat treatment is mainly used prior to the pressing of berries.
a) True
b) False
View Answer
Explanation: Preparation with heat treatment is mainly used prior to the pressing of berries. Since, it can increase juice yield by 5–10%. The amount of substances diffused is in direct proportion with the diffusion coefficient, the active surface, and the concentration gradient. Active surface can be increased by proper chopping.
12. Which of the following enzymes are used in liquefaction of fruits?
a) Amylases
b) Pectinase
c) Glucosidases
d) Lipase
View Answer
Explanation: As an alternative to press systems, some processors use enzymatic liquefaction of the fruit mash. Cellulases and pectinase enzymes are added to the fruit. It is then mashed properly. The mash is heated in order to accelerate the enzyme’s performance.
13. Which chemical is used for the determining the pectin content in the juice?
a) Ethanol
b) Methanol
c) Ammonia
d) Butanol
View Answer
Explanation: The juice can be checked for pectin content using a qualitative test. The method involves combining one part of juice with two parts of ethanol. When combined, if a gel is formed it depicts that the pectin is present in the juice. At the completion of depectinization a floc is produced by the collection of partially degraded pectin-protein molecules.
14. What is the minimum temperature of pasteurizing the fruit?
a) 150–170°C
b) 50–60°C
c) 20–40°C
d) 70–90°C
View Answer
Explanation: Once the juice has been clarified, it is ready to be preserved. For a single-strength juice packaging line, a typical process is to heat the juice to 70–90°C and then bottle it. This produces a shelf-stable product.
15. What is the key advantage of using plate and frame filter press?
a) The dryness of the cake
b) Cleaning process
c) Requirement of labor
d) Cleaning process and requirement of labor
View Answer
Explanation: The plate and frame filter press involves low capital cost, high flexibility for different types of products. It can be easily maintained. The dryness of the cake is one major advantage with the plate and frame press. The disadvantage associated with this system where the presses must be taken away and cleaned by hand at the end of each cycle.
Sanfoundry Global Education & Learning Series – Fruits Processing.
To practice all areas of Fruits Processing, here is complete set of 1000+ Multiple Choice Questions and Answers.
If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]
