I used plain white flour, but the brand (Bacheldre Watermill Stoneground Plain Unbleached White Flour) wasn't as refined as the usual ones so the rolls turned out slightly brown.
And more and more, spirulina is also being used as a cooking ingredient – in hot dogs and meatballs, and as a protein-rich substitute for eggs in pasta and mayonnaise.
Many cooks think darker egg yolks are fresher or healthier. But the color may be the result of marigold petals, alfalfa or coloring products in food for chickens.