Croissant-ologyVia Physics Today: The fat in a perfect...

Croissant-ology

Via Physics Today: The fat in a perfect croissant (PDF)

Image caption:

Croissants are appealingly flaky because of the types of fats, called roll-in fats, that are used to make them.

(a) Roll-in fats respond differently to being deformed than do all-purpose fats. The plots show how internal forces (stress is force per unit area) develop as a fat is periodically deformed (strain is the amplitude of the relative size increase) at an angular frequency of 3.6 radians per second. The sharp buildup and sudden fall of stress in the all-purpose fat signals a failure of internal structure. (Adapted from B. Macias Rodriguez, A. G. Marangoni, Crit. Rev. Food Sci. Nutr., in press, doi:10.1080/10408398.2017.1325835.)

(b) In fats, triglyceride molecules crystallize into nanoscale platelets, such as those shown in this electron micrograph. The platelets represent the smallest scale of three structural levels in a roll-in fat.

© This electron micrograph shows part of the largest-scale structural feature in fats, a microscale crystal network in which liquid oil can be embedded.