Question

Food Science Question

Q) You have developed a beef jerky (dried meat product) that has a moisture content of 41% and water activity of 0.87 at 20C. The beef jerky is packaged in a plastic wrapper that is impermeable to moisture migration. The product is to be part of a MRE (meals ready to eat) for soldiers in the Middle East where the average day time temperature is 35C.

a. Discuss the effect of the effect of storage on the water activity of the beef jerky. Explain the relationship between temperature and water activity.

b. Discuss how you could alter the formulation to reduce the water activity of beef jerky without changing the moisture content. Discuss why this method would be effective.

Answer 1

water activity is ratio of vapor pressure of water present in food /to vapor pressure of pure water

As the temperature increases water activity of substance increase ( vapor pressure of water in food increases)

(a) As the temperature in Middle East is 35 oC which is more than 20 oC so the water activity of beef jerky increases

(b) to reduce water activity keep the beef jerky refregerated or store at lower Temperature, it is one of the best way to reduce water activity

lower water activity also reduce the action of micro-organism. thats why its study is important.