Use a 23× 3cm loaf tin. Coat tin with cooking spray. Preheat oven to 180°C.
Blanch peaches in a saucepan of boiling water for 20 seconds. Peel, pit and finely chop; you will need about 185 g (1 cup) of peach flesh.
Combine flours, wheat germ, sugar, bicarbonate of soda and salt in a large bowl. Combine sour cream, egg, egg whites, oil and the essence in a separate bowl. Make a well in the centre of dry ingredients. Pour in sour cream mixture; stir just until combined. Fold in peaches.
Spoon batter into tin; level the top. Bake for about 1 hour until a skewer inserted in centre comes out clean. Place tin on a wire rack; cool loaf in tin for 10 minutes. Turn out onto rack to cool completely.
The ‘heart’ of the wheat kernel, wheat germ has a nutty flavour; it contains cardioprotective nutrients which include vitamin E, folate, magnesium and zinc. It's easy to use wheat germ in your meals: add it to smoothies, pie and crumble toppings and to breadcrumbs for coating chicken or fish or burgers.