Food Science & Technology Flashcards

Which sugar-related reaction requires a reducing sugar and an amino group and is responsible for browning in seared steak?

Answer: Maillard reaction

The Maillard reaction occurs between reducing sugars and amino groups, producing brown pigments and savory flavors.

A product's water activity (aw) of 0.85 is closest to the minimum level that inhibits growth of which group?

Answer: Most pathogenic bacteria

Most pathogenic bacteria, including Staphylococcus aureus under aerobic conditions, are inhibited at aw below about 0.85–0.86.

Which hydrocolloid forms thermoreversible gels that melt near body temperature and is derived from collagen?

Answer: Gelatin

Gelatin is hydrolyzed collagen that forms thermoreversible gels melting around 35 °C.

Starch gelatinization primarily involves which change?

Answer: Starch granules absorb water and swell when heated

Heating in water causes granules to swell, lose crystallinity, and thicken the system.

Retrogradation of starch in bread is the main cause of which quality change?

Answer: Staling

Recrystallization of amylopectin and amylose during storage firms the crumb and causes staling.

An oil-in-water emulsion such as mayonnaise is stabilized mainly by which component?

Answer: Lecithin in egg yolk

Egg yolk lecithin and proteins adsorb at the oil–water interface to stabilize droplets.

Which enzyme is chiefly responsible for browning of cut apples?

Answer: Polyphenol oxidase

Polyphenol oxidase oxidizes phenolic compounds in the presence of oxygen to form brown melanins.