Starch retrogradation: it’s been attacking our baked goods forever. Now, it’s time to fight back. Stale baked goods are inevitable, but we can hold it off so our products have a longer shelf life.
Why do things go stale?
Moisture loss, right? Well, it’s a little more complicated than that. While it may accelerate it, staling is caused by the recrystallization of starch molecules, or starch retrogradation. Gluten cross-links in structure of the product and moisture re-distribution are also responsible.
Here are 5 tips to slow staling down:
Storage Temperatures: Stay around 25°C (77°F) or -18°C (-0.4°F).
Processing Factors: lower baking temperatures, or shorter baking times and larger loaf volumes reduces staling.
Enzymes: alpha amylase, pullulanase, lipase, lipoxygenase, protease and other non starch polysaccharide-modifying enzymes slow starch retrogradation.
Surface Active Lipids: DATEM, SSL, Lecithin and Monoglycerides also help.
Ingredients: Many bread recipes call for the addition of fat, wheat gluten, and high protein flour. Sugar is another common addition utilized to prohibit staling by helping retain water in bread.
How do you measure it?
There are numerous ways to study staling:
- Rheological methods: Uniaxial compression and pasting properties
- Thermal analysis
- Infrared spectroscopy: Fourier transform infrared (FTIR), near infrared (NIR) reflectance, and nuclear magnetic resonance (NMR) spectroscopy
- X-ray crystallography
- Microscopy: Transmitted and polarized light, confocal laser scanning(CLSM) and electron
- Sensory/organoleptic tests