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Fruit Juice Biochemistry

Description: This quiz is designed to assess your understanding of the biochemical composition and properties of fruit juices.
Number of Questions: 15
Created by:
Tags: food fruit juices fruit juice biochemistry
Attempted 0/15 Correct 0 Score 0

Which of the following is the primary sugar found in fruit juices?

  1. Glucose

  2. Fructose

  3. Sucrose

  4. Maltose


Correct Option: B
Explanation:

Fructose is the dominant sugar in most fruit juices, contributing to their sweetness and energy content.

What is the main organic acid present in citrus fruit juices?

  1. Citric acid

  2. Malic acid

  3. Tartaric acid

  4. Ascorbic acid


Correct Option: A
Explanation:

Citric acid is the predominant organic acid in citrus fruit juices, imparting a sour taste and contributing to their acidity.

Which of the following vitamins is commonly found in high concentrations in fruit juices?

  1. Vitamin A

  2. Vitamin C

  3. Vitamin D

  4. Vitamin E


Correct Option: B
Explanation:

Vitamin C (ascorbic acid) is abundant in many fruit juices, particularly citrus juices, and is an essential nutrient for immune function and antioxidant defense.

What is the primary pigment responsible for the color of orange juice?

  1. Carotene

  2. Anthocyanin

  3. Chlorophyll

  4. Betalain


Correct Option: A
Explanation:

Carotene, specifically beta-carotene, is the major pigment in orange juice, contributing to its characteristic orange color and providing provitamin A activity.

Which enzyme is primarily responsible for the breakdown of pectin in fruit juices?

  1. Pectinase

  2. Cellulase

  3. Amylase

  4. Lipase


Correct Option: A
Explanation:

Pectinase is the enzyme that specifically targets and breaks down pectin, a complex polysaccharide found in fruit cell walls, helping to clarify and stabilize fruit juices.

What is the primary role of polyphenols in fruit juices?

  1. Sweetening

  2. Coloring

  3. Antioxidant activity

  4. Thickening


Correct Option: C
Explanation:

Polyphenols, such as flavonoids and phenolic acids, are known for their antioxidant properties, helping to protect fruit juices from oxidative damage and contributing to their potential health benefits.

Which of the following factors can significantly affect the flavor and aroma of fruit juices?

  1. Fruit variety

  2. Ripeness stage

  3. Processing conditions

  4. Storage conditions


Correct Option:
Explanation:

Fruit variety, ripeness stage, processing conditions (e.g., temperature, time, and equipment), and storage conditions (e.g., temperature, light, and oxygen exposure) can all influence the flavor and aroma of fruit juices.

What is the primary role of enzymes in fruit juice processing?

  1. Clarification

  2. Flavor enhancement

  3. Color stabilization

  4. Nutrient enrichment


Correct Option: A
Explanation:

Enzymes, such as pectinases and cellulases, are primarily used in fruit juice processing for clarification purposes, helping to break down cell wall components and improve juice clarity and stability.

Which of the following is a common method for preserving fruit juices?

  1. Pasteurization

  2. Sterilization

  3. Freezing

  4. Chemical preservatives


Correct Option:
Explanation:

Pasteurization, sterilization, freezing, and the use of chemical preservatives are all common methods employed to preserve fruit juices and extend their shelf life.

What is the primary role of ascorbic acid (vitamin C) in fruit juices?

  1. Sweetening

  2. Color enhancement

  3. Antioxidant activity

  4. Thickening


Correct Option: C
Explanation:

Ascorbic acid (vitamin C) acts as an antioxidant in fruit juices, helping to protect them from oxidative damage and maintaining their nutritional value and quality.

Which of the following is a common method for concentrating fruit juices?

  1. Evaporation

  2. Reverse osmosis

  3. Freeze concentration

  4. Membrane filtration


Correct Option:
Explanation:

Evaporation, reverse osmosis, freeze concentration, and membrane filtration are all commonly used methods for concentrating fruit juices, reducing their water content and increasing their flavor and nutritional content.

What is the primary role of citric acid in fruit juices?

  1. Sweetening

  2. Color enhancement

  3. Acidity regulation

  4. Thickening


Correct Option: C
Explanation:

Citric acid plays a crucial role in regulating the acidity of fruit juices, contributing to their characteristic tartness and helping to preserve their flavor and quality.

Which of the following is a common method for clarifying fruit juices?

  1. Centrifugation

  2. Filtration

  3. Flotation

  4. Enzymatic treatment


Correct Option:
Explanation:

Centrifugation, filtration, flotation, and enzymatic treatment are all commonly used methods for clarifying fruit juices, removing solids and impurities to improve their appearance and stability.

What is the primary role of pectin in fruit juices?

  1. Sweetening

  2. Color enhancement

  3. Thickening

  4. Antioxidant activity


Correct Option: C
Explanation:

Pectin is a complex polysaccharide that contributes to the thickening and texture of fruit juices, helping to create a desirable mouthfeel and body.

Which of the following is a common method for deaerating fruit juices?

  1. Vacuum deaeration

  2. Nitrogen flushing

  3. Carbonation

  4. Filtration


Correct Option: A
Explanation:

Vacuum deaeration is a widely used method for removing oxygen from fruit juices, helping to prevent oxidation and spoilage, and maintaining their flavor and nutritional value.

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