Clean the spinach leaves and chop coarsely. Place salted egg whites, spinach and water in a liquidiser and blend into a juice. Strain the blended vegetable juice through a fine sieve. Mix in alkaline water.
Sift flour into a large bowl and make a well in the centre. Pour in spinach juice.
Bind into stiff dough. Knead the dough until it is smooth and elastic. Cover with a tea towel for 20-30 minutes. Roll out dough into a rectangle and cut into quarters. Dust each piece lightly with flour.
Put a quarter piece of dough through a noodle machine. Adjust the knob of the machine to the thickness you desire. Pass the dough through the cutting machine to get strands of noodle. Repeat the procedure with the remaining pieces of dough. Sprinkle the noodles with a little flour and toss lightly to separate.
Keep the noodles chilled in an airtight plastic container in the refrigerator for 2-3 hours before using.