1. Introduction
Beyond their intrinsic nutritional value, bakery products can be developed into functional foods when certain bioactive compounds such as dietetic fibres, prebiotics, omega-3 fatty acids, antioxidants, are included in the formulation. Additionally, their nutritional quality can be improved replacing part of the saturated fats by healthier ones, or incorporating animal proteins of better amino acidic score (Pérez, Osella, De la Torre, & Sánchez, 2008). Breads are usually cheap, easily packed, stored and conveyed, widely known and preferred by mankind throughout the world. Regardless of economical and social status, bread has always been on the consumer table either to accompany meals or in some cases as the only food. Wheat bread is a typical example; however, in spite of providing calories and some nutrients, it is not a complete food from a nutritional point of view. Legume flours have higher protein content, being proposed as an alternative source for populations with less economical resources; this is the case of soybean, widely produced in Argentina, which also supplies minerals and fibre. Another way to improve a bread nutritional quality is to mix grain flours with animal proteins; it looks especially convenient to consider some food industry by-products such as dehydrated bovine serum or whey.
Bread is a highly perishable product which mainly d