New mill process for the production of bioactive-rich ingredients based on industrial progressive pearling of common wheat.

The pearling process could be an interesting tool in order to produce new ingredients and flour mixes with technologically optimized functional and nutritional attributes. The aim of this study was the identification of an intermediate wheat pearling fraction rich in bioactive compounds, but with low risk in contaminants and thus suitable to be used as a functional ingredient. A sequential pearling was employed using two consecutive industrial abrasive-type grain pearlers. Five different pearling procedures were carried out in order to remove a different percentage of external layers or to obtain a balanced or unbalanced regulation between the first and the second pearling step. The outer layers of the wheat kernel were those characterized by the highest contamination of heavy metals and mycotoxins. Considering nutritional parameters, the total dietary fibre, the antioxidant activity and the phenolic acids progressively decreased from external to internal layers of the kernel. On the contrary, alkylresorcinols and -glucans were mainly concentrated in a range of 4% – 7% pearling, thus generally corresponding to the second pearling fractions. For the production of functional ingredients the pearling procedures with the 7% removal of grain weight could offer the best compromise between high nutritional value and low contamination risk.