how do food producers, processors and restaurants “measure” how many calories a certain product has? Always wondering that when reading labels / menus.
In: Chemistry
A calorie is the amount of energy needed to raise one gram (mL) of water one degree celcius.
for measuring, you can burn the food to measure how much energy comes off of it using a calorimeter. a calorimeter works by measuring the mass and temperature of the water before and after burning the food to find the temperature difference.
Yep, underwood pretty much nailed it. “Calories’ are just an amount of thermal energy. We say our body is “burning” food, but it actually kind of is. The food gets reacted with oxygen, releasing heat/energy and carbon dioxide that you breathe out. There are just a bunch of slower middle steps that let your body *use* the energy vs just burning it in a flame, but the overall reaction and energy release are the same.
So to see how much energy is in food, you can dry it out, grind it up, then put some powder in a cup in a water bath. Burn the food powder with oxygen and measure how much the water warms up.
1 calorie = the energy to warm 1 gram of water by 1 degree C, so if you have 1L of water (1000 g) and it warms up by 1 degree when you burn the food sample, the sample has 1000 calories.
Food Calories (with a capital C, which is the same as kcal) = 1000 cal
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