CRC Food Chemistry and Microbiology 2

Question 1

A research chef replaces sucrose with sorbitol in a baked snack and notices far less surface browning. What best explains this?

Accepted Answer

Sorbitol is not a reducing sugar, so it does not participate in Maillard reactions

Answer

Sugar alcohols lack a free carbonyl group, so they cannot react with amino groups in Maillard browning.

Question 2

Which enzyme treatment is commonly used to reduce acrylamide formation in fried potato products?

Accepted Answer

Asparaginase

Answer

Asparaginase converts asparagine, the main acrylamide precursor, into aspartic acid before frying.

Question 3

A sauce thickened with native corn starch weeps liquid after one freeze-thaw cycle. Which starch modification best addresses this?

Accepted Answer

Hydroxypropylation (substitution)

Answer

Hydroxypropyl groups hinder amylose and amylopectin re-association, improving freeze-thaw stability and reducing syneresis.

Question 4

Fresh pineapple added to a gelatin dessert prevents it from setting. What is the cause?

Accepted Answer

Bromelain, a protease, hydrolyzes the gelatin proteins

Answer

Bromelain breaks gelatin peptide chains so the gel network cannot form; heating the fruit first inactivates the enzyme.

Question 5

Which pathogen is the primary concern when large batches of cooked beef stew are cooled slowly overnight?

Accepted Answer

Clostridium perfringens

Answer

C. perfringens spores survive cooking and germinate rapidly as large volumes cool slowly through the danger zone.

CRC - Certified Research Chef Practice Test