principle od dietetics

Question 1

What is the water content range in fruits and vegetables?

Answer 1

75-93%

This range indicates the high moisture content that contributes to their overall nutritive value.

Question 2

What are the primary nutrients found in fruits and vegetables?

Answer 2

Carbohydrates, some minerals, vitamins C and A, some B vitamins

Fruits and vegetables contain a mix of macronutrients and micronutrients essential for health.

Question 3

What causes the crispness in fruits and vegetables?

Answer 3

Osmotic pressure of water-filled vacuoles

Turgor pressure is vital for maintaining the structure and texture of fresh produce.

Question 4

What happens to hemicellulose and lignin as fruits and vegetables age?

Answer 4

Increase in hemicellulose and lignin

These changes contribute to the softening of produce with age.

Question 5

What is the limiting amino acid in soybeans?

Answer 5

Methionine

This means that methionine is present in the lowest quantity compared to other essential amino acids.

Question 6

What is the protein content of protein concentrates and isolates derived from soybeans?

Answer 6

Protein concentrates: 70-90% protein; protein isolates: ≥ 90% protein

These products are used in various food applications including textured vegetable protein.

Question 7

What chemical changes occur during the ripening of fruits?

Answer 7

Starch converts to sugar; protopectin converts to pectin then to pectic acid

These transformations affect the texture and flavor of the fruit.

Question 8

What role does ethylene gas play in fruit storage?

Answer 8

Accelerates ripening of fruits

Ethylene is a natural plant hormone involved in the ripening process.

Question 9

What is the best storage condition for most produce?

Answer 9

Refrigerator

Proper refrigeration helps maintain freshness and extends the shelf-life of produce.

Question 10

At what temperature should frozen fruit be stored?

Answer 10

At or near 0°F

This temperature is crucial for preserving the quality of frozen fruits.

Question 11

Which fruits ripen best at room temperature?

Answer 11

Avocados, bananas, pears, tomatoes

These fruits continue their ripening process off the plant, requiring ambient temperatures.

Question 12

What is the effect of controlled atmosphere storage on apples?

Answer 12

Delays aging

Reduced oxygen levels in storage environments help to preserve the quality of apples.

Question 13

What are climacteric fruits?

Answer 13

Fruits that ripen post-harvest (e.g., peach, pear, banana, apple, tomato)

These fruits can continue to ripen after being picked, influenced by ethylene gas.

Question 14

What are non-climacteric fruits?

Answer 14

Fruits that are best when ripened before harvest (e.g., grapes, melon, citrus)

These fruits do not ripen significantly after being harvested.

Question 15

How should raw fruits and vegetables be cleaned?

Answer 15

Wash to remove dust and spray residues

Proper washing is essential for food safety.

Question 16

Why should berries and mushrooms be washed just before serving?

Answer 16

To prevent spoilage and maintain quality

Washing them too early can lead to moisture buildup and degradation.

Question 17

What happens to fruits low in vitamin C when cut?

Answer 17

Darken rapidly due to enzymatic action

This enzymatic browning can affect the visual appeal and perceived freshness of the fruit.

Question 18

How can enzymatic browning in fruits be prevented?

Answer 18

Dip in citrus juice, add sugar before freezing, heat to boiling

These methods can help maintain color and quality.

Question 19

How much juice does one dozen oranges yield?

Answer 19

One quart (950 ml)

This yield can vary based on the juiciness of the oranges.

Question 20

What effects does cooking have on fruits and vegetables?

Answer 20

Softens cellulose, increases keeping quality, cooks starch to sugar

Cooking enhances digestibility and palatability.

Question 21

What is the density of syrup expressed as when sweetener is added to the liquid of packing juice?

Answer 21

Percentage by weight of sucrose

This is measured using degrees Brix with a Brix hydrometer.

Question 22

What are the classifications of syrup based on density?

Answer 22

Extra light, light, heavy, extra heavy syrup

These classifications help consumers understand the sweetness and density of the syrup.