Enhancing bread quality and shelf life
A research published in 2022 aimed to develop an approach for the enhancement of the quality aspects and longevity of bread, with the immobilization on an Aspergillus niger-purified enzyme on zinc oxide nanoparticles (ZnONPs) and immersing in a buffered solution to create a mixture of GOx/ZnONPs.

The shelf life of bread treated so was greatly extended, and the microbiological load, including yeast and mold, and total bacterial count were much lower than in the control group.

The most common enzyme employed in the bread baking business is glucose oxidase which is derived from several fungi, mostly from Aspergillus niger. The most significant industrial use of GOx is to extend the food products’ shelf life. Under Food and Drug Administration (FDA) classification, it is generally recognized as safe (GRAS). However, due to its instability, it has limited industrial applications; therefore, going forward, a novel target is to make it stable by immobilization.

According to the article, research by Lee et al. (2018) demonstrated that enzymes based on nanoparticles had better stability and strength in comparison to their counterparts. The zinc oxide nanoparticles (ZnONPs) have antibacterial capabilities as well as zinc acting as a nutritional supplement. ZnONPs are now reported in the packaged food market as a preferred alternative.

EFSA assessed the safety of the substance zinc oxide, nanoparticles, for use in food contact materials in 2016. The assessment was based on the Scientific Committee on Food evaluation of 2003, which recommended an upper limit of 25 mg/person per day based on a no observed adverse effect level of 50 mg/person per day. As the substance does not migrate in nanoform, the 2016 assessment of EFSA focussed on the migration of soluble ionic zinc. It was concluded that the migration data for ionic zinc coming from the substance used in low-density polyethylene complied with the current specific migration limit, but in combination with the dietary exposure from other sources the upper level (UL) of 25 mg/person per day could be exceeded.

Considering that an upper intake level is established for zinc and the current food preservation application operates with nanoparticles, this product would fall in the scope of the Novel Food Regulation in Europe and would require safety assessment before marketing in the EU.


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