Editing Croissant (section)

===Storage===
The effect of [[gluten]] proteins during cooling and storage is still unclear. It is possible that gluten proteins influence croissant firming through the loss of plasticizing water, which increases the stiffness of the gluten network.<ref>{{Cite journal|last1=Bosmans|first1=Geertrui M.|last2=Lagrain|first2=Bert|last3=Ooms|first3=Nand|last4=Fierens|first4=Ellen|last5=Delcour|first5=Jan A.|date=2013-05-15|title=Biopolymer Interactions, Water Dynamics, and Bread Crumb Firming|journal=Journal of Agricultural and Food Chemistry|volume=61|issue=19|pages=4646–4654|doi=10.1021/jf4010466|pmid=23631677|bibcode=2013JAFC...61.4646B |issn=0021-8561|url=https://lirias.kuleuven.be/handle/123456789/422718|access-date=5 February 2019|archive-date=25 July 2018|archive-url=https://web.archive.org/web/20180725014504/https://limo.libis.be/primo-explore/fulldisplay?docid=LIRIAS100198&context=L&vid=Lirias&search_scope=Lirias&tab=default_tab&lang=en_US&fromSitemap=1|url-status=live}}</ref>

Starch plays a major role in the degradation of croissants during storage. [[Amylopectin]] retrogradation occurs over several days to weeks, as amorphous amylopectin chains are realigned into a more [[crystalline]] structure.<ref name=":0" /> The transformation of the starch causes undesirable firmness in the croissant. Additionally, the formation of the crystal structure of amylopectin requires the incorporation of water. [[Retrogradation (starch)|Starch retrogradation]] actively draws water from the amorphous gluten network and some of the amorphous starch fraction, which reduces the plasticity of both.<ref name=":0" />

Water migration influences the quality of stored croissants through two mechanisms. First, as previously stated, water redistributes from [[gluten]] to [[starch]] as a result of [[Retrogradation (starch)|starch retrogradation]]. Secondly, during the baking process, a moisture gradient was introduced as a result of heat transfer from the oven to the croissant.<ref name=":0" /> In fresh croissants, there is high moisture content on the inside and low moisture content on the outside. During storage, this moisture gradient induces water migration from the inside to the outer crust. On a molecular level, water is lost from the amorphous [[starch]] fraction and [[gluten]] network. At the same time, water diffuses from the outer crust to the environment, which has less moisture.<ref>{{Cite journal|last1=Gray|first1=J.A.|last2=Bemiller |first2=J.N.|date=2003|title=Bread Staling: Molecular Basis and Control |journal=Comprehensive Reviews in Food Science and Food Safety|volume=2|issue=1|pages=1–21|doi=10.1111/j.1541-4337.2003.tb00011.x |pmid=33451240|issn=1541-4337|doi-access=}}</ref> The result of this redistribution of water is a firming up of the croissant, caused by a decrease in starch plasticity and an increase in gluten network rigidity. Due to the presence of large pores in croissants, moisture is lost to the environment at a faster rate than bread products.<ref name=":2">{{Cite journal|last1=Roca|first1=Elisabeth|last2=Guillard |first2=Valérie|last3=Guilbert|first3=Stéphane|last4=Gontard|first4=Nathalie|date=2006-03-01|title=Moisture migration in a cereal composite food at high water activity: Effects of initial porosity and fat content |journal=Journal of Cereal Science|volume=43|issue=2|pages=144–151|doi=10.1016/j.jcs.2005.08.008}}</ref> As such, croissants generally become harder in texture at a faster rate than breads.

Fat also affects the quality of croissants in storage. On one hand, an increased amount of in-dough fat has been found to correspond to a reduction in crumb hardness immediately after baking.<ref name=":0" /> This is likely attributed to the high-fat content of croissants, as increased fat levels decrease moisture diffusion.<ref name=":2" /> On the other hand, although roll-in fat softens the croissant’s initial crumb, its effect on croissant hardness during storage is still unclear.