Evaluation of the effect of edible coating on mini-buns during storage by using NIR spectroscopy

Moisture migration plays an important role in the stability and quality of bakery products. In this study, pectin, alginate and whey protein edible coating was used as an edible barrier to evaluate its effectiveness for retaining the quality of bread by reducing moisture loss and textural changes during storage. Mini-buns as model systems were applied with 1 layer and 2 layers of coating and evaluated for moisture and texture attributes by both mechanical and spectroscopic techniques. The coatings displayed a retaining effect with the percentage increase in crumb hardness lower for coated samples (1 L: 126.5% and 2 L: 231.2%) than control samples (Control: 271.8%). Further, the spectral data for the crust and crumb surfaces were pre-treated and subjected to Principal Component analysis (PCA) for the evolution along storage time. In particular for moisture content, discrimination at 8 h for crust and after 24 h for crumb was noted for both 1 L and 2 L coating layers with a R-2 > 0.85. Subsequently, PLS models with spectral data described satisfactorily the evolution of hardness with low (<10.8) RMSE values.