An integrated chemical and technological approach for assessing portuguese wheat flours quality and lengthening bread shelf-life

The current trend of large-scale bread production is to facilitate processing at an industrial level, considering the use of flour mixtures with different chemical and technological parameters and incorporating food additives. Accordingly, costs can be minimized, whereas the quality and the shelf-life of the final product might increase, but a full characterization of the flours that must be used and the selection of the food additives to be incorporated into the dough is required. In this context, three Portuguese wheat flour varieties were evaluated (FariRamos, Nacional and AJMiranda), as well as two types of food additives with the aim to increase bread shelf-life. In these flours, the levels of K, S, P, Ca and CI prevailed, but the moisture and ash contents of FariRamos were the highest and lowest, respectively. The colour of all flours was generally within the desired standard values. Nacional flour contained a higher fat content, but all the flours showed a higher relative abundance of linoleic acid (C18:2), followed by palmitic acid (C16:0) and oleic acid (C18:1). AJMiranda flour revealed a higher content of wet gluten and protein, but the SDS sedimentation index showed a higher value in the FariRamos flour. The fall index, which directly monitors the activity of the alpha-amylase enzyme, showed a lower value in AJMiranda and Nacional. Through farinograph and alveographyc analysis it was found that FariRamos has a tenacious gluten, but AJMiranda and Nacional had a balanced gluten, yet all of them can be classified as medium flours. Bread making with a mix of FariRamos, AJMiranda and Nacional flours and incorporating preservative food additives revealed the highest shelf-life (11-days) with methyl p-hydroxybenzoate [0.05 %J and benzoic acid [0.1 %), but the colour of the breads showed a relationship of intensity of white colour that depended on the additive used. At the end of the shelf-life, molds of the Eurotium, Trichoderma and Cladosporium genera developed in the bread. It was concluded that the chemical and technological approach applied in the characterization of the flour varieties, can be directly used to define the quality and shelf-life in the bakery industry, allowing the establishment of minimum commercialization prices.