10 d

Question 1

• caffeinism:

Answer 1

> 500mg/day (4-7 cups of coffee/7-9 cups of tea restlessness, anxiety, irritability, agitation, muscle tremor, insomnia, headache, diuresis, cardiovascular symptoms (e.g. arrhythmia), GI tract complications (nausea and diarrhoea)

- blocks central nervous system receptors (adenosine receptors) 	 with adenosime binding neural activity slows down (important for sleep and proper brain and body oxygenation “breaking down” Stops the breaking down process

Question 2

lethal dose of caffeine

Answer 2

10g

Question 3

tannins

what are they

Answer 3

• secondary plant metabolites synthesized through the acetate and shikimate pathways  phenylalanine and tyrosine
  
  • naturally occurring polyphenolic compounds->molecular masses of 300-3000
  • catechin and epicatechin/100g: fruits (5-20 mg); tea (3-11 mg); red wine (~10 mg); chocolate (8-54 mg)powerful antioxydant
    Quorcitan- most abundantly comsummed phenolic compound

Question 4

most common form of tannin

Answer 4

-hydrolysable tannins-> contain a central carbohydrate + polyphenols

Question 5

(most abundant form of tannins in nature)

Answer 5

condensed do not contain a carbohydrate moiety

Question 6

example of a condensed tanin

Answer 6

: proanthocyanidins precursors to anthocyanidins, which are responsible for the wide range of plant/fruit/flower colours
Important for scientists as moving away from artificial colours- the
problem with them: they lose their color- ph labile

Question 7

(8) Tannins

Toxicity

Answer 7

• cross-linking with proteins, DNA and RNA (comprimises cell division and protein synthesis)
  • first compounds of plants origin that were shown to be carcinogenic in animal studies (6-9kg/bwt)-> bladder, colon, esophageal and lung
  • animal diets (3%)  reduced weight gains, decreased egg production  related to a decrease in protein absorption due to binding
  -enzyme (digestive) activity inhibition (i.e. binding)-> amylase, alpha-glucosidase, lipase and trypsin (protease)

Binding of tannins to proteins makes them less available for uptake and reduces enzyme activities that are important for nutrient uptake.

Question 8

what can we do to reduce tannins

Answer 8

• physical removal  dehulling of grains (insect eating)
  
  • chemical treatment  steam/alkali treatment (problem?: cost, nutrient destruction)
  • genetic manipulation conventional breeding, genetic engineering (problem: consumers don’t want it
    Chemical treatments are not the best option: destruction of nutrients, colour formation (dark), off-flavour production

Question 9

Tannins

Functions in plants

Answer 9

• repair of damaged tissue
  
  • chemical defence animals (e.g. birds), insects, microbes; protein/DNA binding (metabolic arrest; cell division inhibition)

Damaged tissue repair: important as damaged tissue is an avenue for microbial growth and insect infestation, and of great importance water loss  looks like tannins are being released by the plant to heal a cut/damage in its tissue.

Animals (e.g. monkeys, gorillas) avoid plant materials containing high levels of tannins  astringent taste (rough, dry and chalky; tactile sensation like cold and heat and not really a flavour) and visual

Question 10

tannins

Products for humans

Answer 10

Tabit: improved gut health (HOW? I’m not sure) reports intself as “gastrointestinal support”
Tanafem: antimicrobial action (yeast and bacteriavaginal health)
AMLA Gold: immune, vision and liver health  most likely due to antioxidant activity
Red one (Daphin) is as a WRINKLE REMOVERSRELATE TO LEATHER MANUFACTURE (

Question 11

Tannins
Sorghum (cereal)
limitation

Answer 11

• important food crop for humans (Africa, Central America, South Asia; ranks 5th in world cereal crop production)  >600 million people/30 countries (poor and food insecure)
• benefits: calories, nutrients (protein [~12%], starch [~74%], lipid [~4%], ash [~2%], rich in B-complex vitamins), antioxidant properties (cancer and cardiovascular disease prevention)
  limitations: rich in tannins (toxic properties, poor taste), poor essential amino acid content

Question 12

Select Compounds

(a) saponins

toxicity

Answer 12

• triterpenes (C30) that are normally covalently linked to carbohydrates (glycoalkaloid)
  
  • exhibit foaming properties  surface active agent (i.e. surfactant/detergent)
  • present in: asparagus, beets, peanuts, potatoes, spinach, legumes (e.g. beans) + other vegetables and nuts

These belong to a group of compounds called glycoalkaloids
You may observe this detergent action when you are washing the surface of a potato.

(a) saponins (toxicity) acid, water air- foaming action

- powerful haemolyzing agents  destruction of red blood cells
(RBC; extremely toxic to cold blooded animals [e.g. fish])- peru fish death

- animal toxicity (mice): significant RBC destruction; liver and 	kidney necrosis (5 g/kg bwt/day for 90 days [LD50: 8.5 g/kg bwt]); 
- human toxicity?  3-6 mg/kg bwt:GI disorders, vomiting, stomach cramps, fever, jaundice, partial paralysis; human teratogen;-> readily excreated intact (not absorbed)-> surfactant property (toxic compound removal?)

Question 13

catechin epicatechin

Answer 13

fruits (5-20 mg); tea (3-11 mg); red wine (~10 mg); chocolate