NUTR2001 Lecture Notes - Lecture 3: Electron Donor, Collagen, Elastin
27 Aug 2018
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Stability: pka is 4. 2, therefore more stable in acid form, more stable in foods, temperature, light. Packing can protect food source from light: o2, metals (cu & fe) Fe3+ may pick up electrons from vitamin c and result in ascorbate being oxidised, therefore potentially losing it in metabolic pathway: hydrolytic ring rupture. Food sources: naturally occurring, added by food industry. Foods with high [vitamin c] may not be the best source if they are not consumed in large amounts e. g. parsley 100mg/100g. Not all gets converted back to ascorbate due to catabolism. Main waste product in urine oxalic acid. Citrus fruits good source as more readily available. Unexpected sources cereals for non-haem iron absorption and. Sauerkraut good source as lactobacillus fermentation reduces ph, Brush border svct1 (sodium dependant vitamin c co-transporter) Svct2 (another transporter but from same family gene product and vitamin c is most stable in acid form.
