A simple google search found the answer:
"The average person secretes about 400 mL of gastric juice per meal, containing 50 to 300 µg pepsin/mL. For an average of around 200 µg/mL × 400 mL of gastric juice, this would be 80 mg (or 0.080 g) pepsin/meal. For HCl with a concentration of around 6.08 g/L × 400 mL, this would be 2.4 g/meal."
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