Galit Segev is a chef and biochemist and is a part of the Ultimo Science Festival and she is giving a talk on the science of chocolate. In her family home kitchen at Lane Cove. SMH NEWS Photo: Domino Postiglione
''The different types of crystal are sensitive to different temperatures'' … Galit Segev, a chef and biochemist, will give a talk at Ultimo Science Week. Photo: Domino Postiglione
WHEN most chocolate lovers snap off a cube of chocolate they are not thinking about its delicate crystal structure, nor do they ponder the percentage of milk proteins it contains as it melts in their mouth.
Galit Segev enjoys her chocolate as much as anyone else, but as a chef and a biochemist she is also fascinated by its physical properties.
She even eats white chocolate, despite it not technically being a chocolate.
Mrs Segev, who uses her background as a biochemist in the pharmaceutical industry to inform her cooking, is interested in why food behaves differently under various cooking techniques.
She will give a talk on the science of chocolate as part of Ultimo Science Week on Wednesday evening.
As well as talking about how chocolate is manufactured, from a cocoa farm to the supermarket shelf, Mrs Segev will explain what makes a good quality chocolate.
She will discuss the differences between dark, milk and white chocolate. Dark and milk varieties contain cocoa powder while white chocolate contains cocoa butter, a pale vegetable fat extracted from the cocoa bean that is solid in room temperature but will melt in your mouth.
When chocolate leaves an oily film on the roof of the mouth it usually means it has been made using a cheaper fat such as palm oil rather than cocoa butter, Mrs Segev said, who teaches cooking in Rozelle and private lessons.
Cocoa butter is a complex fat that could solidify or crystallise into six different forms that required precise temperature control to create, she said.
''The different types of crystal are sensitive to different temperatures.
''In chocolate we are after a particular type of crystal. They look like stars under an electron microscope,'' Mrs Segev said.
The characteristic snap of a good quality dark chocolate came from these crystals sitting close together in a compact structure, created by heating and cooling the chocolate at precise temperatures - a process called tempering, she said.
''If you have ever left chocolate in your car you may have noticed grey powdery appearance that appears on the chocolate. This is chocolate that is out of temper,'' Mrs Segev said.
But out of temper chocolate, which results when chocolate is not melted and cooled at correct temperatures, is not out of date and is safe to eat, she said.
A chocolate company may have good marketing strategy but the quality is questionable, especially here in Malaysia.