Fruits & Vegetables

Question 1

1. Give the botanical definition of fruit and state whether or not this includes fleshy or dried fruit.

Answer 1

• Mature seed-bearing structures of fruit
• Does not include fleshy fruit from growth from structures other than the ovary
• Does include dried fruit (nuts, grains, legumes)

Question 2

2. Give the botanical definition of vegetables.

Answer 2

• Soft, edible structures that have developed in the main from other parts of the plant

Question 3

3. Give the consumer definition of fruit in UK.

Answer 3

• Plant products with aromatic flavours, which are either naturally sweet or normally sweetened before eating
  (includes rhubarb, normally a veg)

Question 4

4. Give the consumer definition of vegetables in UK.

Answer 4

• Soft edible plant products that are commonly salted (or at least not sweetened), cooked, often eaten with meat or fish
• (includes tomato, cucumber, pepper, sweetcorn -> botanically fruits)

Question 5

5. Does the composition of F&V change post-harvest and why?

Answer 5

• YES

- F&V are metabolically active and constantly change composition pre- and post-harvest

Question 6

6. List factors which influence changes in F&V composition.

Answer 6

• Physiological role of plant tissue (seeds, leaves, roots)
• Stages of maturity of plant (fruit ripeness)
• Environmental conditions (soil, sunlight, rainfall, temp)

Question 7

7. Give an example of how different physiological parts of a plant differ.

Answer 7

• Seeds contains lipid and starch used for purposes after germination

Question 8

8. Give two important roles of F&V water content.

Answer 8

• Provides cell turgidity which affects the texture and crispness –> consumer preferences
• Important for stability and shelf-life –> bacteria grow well with lots of H2O available

Question 9

9. Give a consequence of inadequate water supply and which plants this affects most.

Answer 9

• Wilting

- Affects harvested plants with a lot of leafy tissue -> more transpiration leads to greater water loss, faster

Question 10

10. Give 3 vegetables and 3 fruits with high water contents.

Answer 10

• Veg: lettuce, tomato, celery
• Fruit: melon, rhubarb, strawberries

[though can have large standard deviations btwn batches]

Question 11

11. State 4 CHO components present in F&V

Answer 11

• simple sugars (glucose, fructose, sucrose)
• fructans (e.g. onions, artichoke -> affect microbial fermentation and so gut function)
• starch (amylopectin 80%/amylose 20%)
• non-starch polysaccharides NSP

Question 12

12. Name the 3 components of NSP and how dietary fibre is calculated.

Answer 12

• Hemicelluloses, pectins, cellulose
• H + P + C + non-CHO components = dietary fibre

[non-CHO = phenolic compounds e.g. cell wall]

Question 13

13. Define hemicelluloses and cellulose.

Answer 13

• H: heterogenous group (arabinogalactans, xyloglucans, arabinoxylans, galactomannans)
• C: different pectins

Question 14

14. State the main function of sugars in F&V and where they are mainly located.

Answer 14

• Sweetness

- Dissolved in cell sap

Question 15

15. What determines the proportion of sugars in F&V?

Answer 15

• Post-harvest processing
• Environment
• Processing

Question 16

16. Describe the sugar content of root vegetables and dried fruit.

Answer 16

• Root veg: rich in sugars (carrots,parsnips)

- Dried fruit: high sugar levels as fibre and sugar are concentrated when water is lost

Question 17

17. Why do boiled peas and lentils contain less starch than raw counterparts?

Answer 17

• higher amount of water = lower proportion of starch (dilution)

Question 18

18. Why do yellow bananas contain less starch than green bananas?

Answer 18

• Dramatic loss of starch as it breaks down into sugars over time (amylase enzymes active)
• Physical properties also change (becomes softer)

Question 19

19. Describe the differences in blood glucose concentration after ingestion of yellow and green bananas.

Answer 19

• Green: slower glucose release, lower peak

- Yellow: faster increase, higher peak (more sugars)

Question 20

20. Name the main NSP

Answer 20

-Cellulose

Question 21

21. State which F&V aspect pectin affects and how this is affected by cooking.

Answer 21

• Affects texture

- Breaks down during cooking, cells no longer stick together -> softer texture

Question 22

22. Define lignin and state its function.

Answer 22

• Non-CHO component of cell walls (esp. vascular tissue), present in small amounts
• complex polymer of aromatic polymers linked by propyl units
• provides rigidity and toughness (mechanical support)

Question 23

23. Explain how lignin presence affects texture and bioavailability of nutrients.

Answer 23

• more lignin -> tougher texture
• lignin not easily digested -> affects fermentation in LI (nutrients it contains will not be released until broken down)

Question 24

24. State the function of other phenolic compounds and give an example.

Answer 24

• Affect mechanical properties of cell wall (texture)
• Ferulic acid (example) is in Chinese water chestnuts and forms cross links with arabinoxylans (in parenchyma tissue) so cells do not separate after hydrothermal processing

Question 25

25. Give 3 protein-rich vegetables

Answer 25

• Spinach
• Sweetcorn
• Leguminous seeds (legumes)

Question 26

26. State what determines protein structure and function and what the main functions are in F&V.

Answer 26

• Amino acids present

- Overall structure, enzyme functioning

Question 27

27. Define what protein quality is and identify the limiting amino acids in legumes and wheat.

Answer 27

• Amounts of essential amino acids present
• Wheat: lysine
• Legumes: methionine

Question 28

28. Give two examples of non-protein N components in F&V.

Answer 28

• purines
• alkaloids (toxic at high conc)
• e.g. green potatoes have high conc of solanine (glucoalkaloid) which is a potent acetyl cholinesterase inhibitor (prevents Ach degradation once stimulus in removed)

Question 29

29. Give two lipid-rich F&V sources

Answer 29

• avocado
• olives (olive oil)
• tree nuts

Question 30

30. State the most common form of lipid and the 3 common fatty acids that these consist of.

Answer 30

• triacylglycerol

- palmitic (C16:0), oleic (C18:1), linoleic (C18:2)