Physical Properties of Flours Obtained from Wasted Bread Crusts and Crumbs

Juan Fernández-Peláez,Manuel Gomez,Priscila Guerra,Cristina Gallego

doi:10.3390/foods10020282

Abstract

One third of the food produced in the world is wasted. Bread is one of the most wasted foods both during the distribution process and in households. To use these breads, it is necessary to get to know the properties of the flours that can be obtained from them. The purpose of this work is to know how the type of bread and its zone (crumb or crust) influence the characteristics of the flours obtained from the wasted bread. For this, flours made from the crumbs and crusts of eight different breads have been analysed. Their hydration properties, cold and post-heating rheology and gelling properties as well as the colour of flours and gels have been studied. Bread flours present higher water-holding capacity (WHC) and water-binding capacity (WBC) values and higher elastic modulus (G’) and viscous modulus (G”) values, both in cold conditions and after heating, than wheat flours. However, they generate weaker gels. Crust flours, and the gels obtained from them, are darker than those from crumbs and their gels. In terms of hydration and rheology, pan and wholemeal bread flours are generally lower than other bread flours. These flours also generate softer gels, possibly caused by the dilution of starch with other components. It can be concluded that the properties shown by wasted bread flours allow them to be reintroduced in the food chain as an ingredient in different products.

Highlights

It is estimated that one third of the world’s food production is wasted
In terms of particle size, it should be noted that all flours obtained from stale bread (SB) have higher values than those of wheat flour
Wheat flours are obtained by a progressive milling system to separate the outer layers of the grain completely, and the final separation sieve is about 200 microns

Summary

Introduction

In Europe, this represents 88 Mt or almost 175 kg per person per year, which amounts to about EUR 143 billion [1]. Such losses imply a high environmental impact, which can be reduced by minimizing these wastes or through better practices in their handling [2]. The European Union advises that when it is not possible to minimise it, food waste should preferably be allocated to human consumption, either directly or after its conversion into new products [5]. Studies on the use of bread waste in human consumption are scarce and limited to its incorporation into extruded snacks [11] and sourdough [12]

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Conclusion