An example of an S-curve for a yeast-leavened wheat dough during baking.

Thermal Profiling for Baking

How is a Thermal Profiling Used in Baking?

Thermal profiling is a baking process for optimization and control. Baking involves many stages such as proofing, baking and freezing operations. This tool allows bakers to read and analyze the change in temperature within a product while it goes through these stages.

A thermal profile helps ensure food safety and regulatory compliance for FSMA. It also helps improve product texture, quality and shelf life by monitoring things like:

  • Yeast kill
  • Bake out zone
  • Product temperature arrival
  • Color development

How does it work?

Thermal profiling measures key variables involved in thermal processing of foods and bakery products. It measures things such as:

  • Internal product temperature over process time is done at one or more points of interest with sensors, and graphical plotting of temperature-time curve.1
  • Convective and radiant heat fluxes used to bake the products (Btu/hr·ft2 or W/m2).1
  • Total heat absorbed by the product during total bake time (Btu/ft2 or Joules/m2).
  • Air velocity in convection ovens (m/s or fpm) and oven (air) temperature (°C/°F).
  • Oven humidity as humidity mass ratio in lb water/lb dry air (kg water/kg dry air).

The fundamental principle of thermal profiling lies in the fact that physical, microbiological and chemical changes in the product during thermal processing occur as a function of internal temperature. Taking the baking step as example, dough enters the oven at normal proofing temperature of 35°C (96°F) and exits as bread at 93°C ( 200°F).

How does thermal profiling work for cake and batter products? Find out in our free technical paper here!

Changes taking place during baking encompass 4 major points:2,3

  • Yeast kill or deactivation: yeast cells in the dough are inactivated at 132°F/56°C. This happens after the product has passed the oven spring stage, the maximum expansion from yeast activity while dough matrix is still stretchable. Ensuring complete yeast kill should take 45–55% of total bake time.
  • Critical change zone: the transition from a viscoelastic dough to a firm, drier and porous or sponge structure.
    • Wheat starch gelatinization: starch granules gelatinization onset is at 65°C (150°F) and is concluded at 82°C (180°F). This process should be completed...

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