Selected non-nutrients: Week 6

a substance that may occur in the diet that may affect our health even though they are not nutrients, plants contain thousands of non-nutrient substances, some of which may be toxic

• FIBRE • CHOLINE: (important for making phospholipids) • PHYTOCHEMICALS: a range of compounds some of which have been associated with health.

-Phenols -Polyphenols -Sulphur containing compound -Alkaloids(e.g caffeine)

-FLAVONOLS: Apple, broccoli, onions -FLAVONES: celery, bell peppers, lemons -ANTHOCYANIDINS: Raspberries, strawberries, grapes, wine -ISOFLAVONES: Soya sauce, milk, tofu

-polyphenols are generally represented as glycosides in the diet - some flavonoid glycosides can interact with transporters in duodenum where they are absorbed - Non-interacting glycoside (rutinoside) pass to colon where bacterial glycosidases degrade them- some absorption may occur

• Simple proteins: only amino acids *Conjugated proteins: amino acids + prosthetic group • Derived proteins: modified by chemical or enzymatic treatment

*Albumins & Globulins: globular& soluble(egg) *Collagen: linear, fibrous & insoluble(connective tissue in meat) *Gluten: Gliadin if globular & Glutenin is fibrous (both in cereal)

-Lipoproteins: LDL, HDL(in egg yolk) -Glycoproteins: in egg white & soya -Metalloproteins: haemoglobin, myoglobin in meat

• chemical modification: soya proteins -Enzymatic modification: milk proteins

-FORMATION OF GELS -STABILISE EMULSION& FOAMS -FORM FILMS

globular proteins unfold on heating- the denatured chains aggregate to form thermally irreversible gels Fibrous proteins are able to form thermally reversible gels: gelatine from collagen

proteins from milk and eggs are commonly used to stabilise oil-in-water emulsions & foams. - they are able to absorb the oil-water & air-water interfaces, preventing aggregation -small enough to diffuse to the interface at fast rates - their interface activity will be a function of their: molecular size, amino acid composition, PH, structure and solvent composition

mayonnaise, sauces, mustard

ice cream- not just an emulsion as instead of oil being the hydrophobic bit, air is instead

Application of proteins such as gelatine, whey, soy, corn and wheat gluten as edible films (refer as edible coatings when applied to fruit and vegetables)

-barrier to moisture & carbon dioxide- enhances shelf life & appearance -biodegradable packaging -improve mechanical handling proteins

-Glucose oxidase: dough strengthening -Lipoxygenase: dough strengthening, dough whitening

-Transglutaminase: modification of viscoelastic properties -Fructosyltransferase: Synthesis of fructose oligomers

-Amylase: Starch liquefaction & saccharification -Lactase- Lactose Hydrolysis

Xylose(glucose) isomerase: glucose isomerization to fructose

Acetolactate decarboxylase: beer maturation

1) Isomerase 2) Invertase 3) Lipoxygenase 4) Protease 5) Lactase

D glucose—> D-fructose fructose is sweeter than glucose- can uses it at higher conc tan glucose to make it ‘healthier’

sucrose +H2O–> alpha-D glucose + beta-D glucose produces sugars for confectionary(sweets) as they are more stable & less likely to crystallise