Learn more: Angina is chest pain or discomfort caused when your heart muscle doesn't get enough oxygen-rich blood. It may feel like pressure or squeezing in your chest. The discomfort also can occur in your shoulders, arms, neck, jaw, or back.Angina pain may even feel like indigestion.But, angina is not a disease.earn more: Angina is chest pain or discomfort caused when your heart muscle doesn't get enough oxygen-rich blood. It may feel like pressure or squeezing in your chest. The discomfort also can occur in your shoulders, arms, neck, jaw, or back. Angina pain may even feel like indigestion.
Definition of leaven. 1a : a substance (such as yeast) used to produce fermentation in dough or a liquid; especially : sourdoughb : a material (such as baking powder) used to produce a gas that lightens dough or batter.
Chemical leavening is the combination of sodium bicarbonate (baking soda) and acidic agents with water to generate carbon dioxide gas in controlled volumes and rates. Ammonium bicarbonate or potassium bicarbonate may be used instead of sodium bicarbonate for some applications.