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The nature of the plasticizer fraction within a bioplastic matrix is of extreme importance. Thus, brittleness has sometimes been observed when water has been used. The goal of the present manuscript has been to assess the effects of the addition of sucrose and trehalose in gluten-based bioplastics either in presence or absence of water. It was found that the role of the disaccharides in the samples studied depended on whether water was present or not in the formulation. Therefore, when water was included in the formulation together with glycerol, sugars were solubilized within the aqueous fraction, and then played a plasticizer role in the bioplastics. In that case, lower torque and temperatures during mixing, as well as lower viscoelastic properties and greater water absorption ability were generally observed in the presence of sugars. On the other hand, when no water was added, sugars acted as fillers, especially sucrose, which reinforced the blends as denoted by lower loss tangents and higher viscoelastic moduli. In this case, a microporous structure is formed after water immersion, observing smaller pore sizes in the positions previously taken by those sugars. The present manuscript highlights the importance of the procedure followed when introducing sugars in the formulation on the eventual properties of the bioplastics.

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Maize (Zea mays L.) is the most important crop in Mexico with a per capita consumption for 2019 of 106.34 kg (SAGARPA, 2019). Maize is mostly used as raw material to obtain maize nixtamalized flours but also because, with nixtamalized maize flours, masa and tortilla are produced. Tortilla is basic food and of higher consumption (about 7.4 million tons per year) in the Mexican population (CEDRSSA, 2014). Industrial production of nixtamalized flour is based on traditional nixtamalization, a thermo-alkaline process in which corn grains are cooked in an oversaturated calcium hydroxide solution (1%-5% w/w based on corn weight). Next, the corn is steeped from 8 to 24 hr and washed to remove excess of lime, pericarp and solids. Nixtamal (alkaline cooked corn, steeped and washed) is ground to obtain masa, which could be used to produce tortillas, tamales, atole, snacks (nachos), and instant corn flours (Valderrama-Bravo et al., 2010). Each unitary operation of the nixtamalization is decisive for obtaining the right quality product, depending on process conditions such as time and temperature. These parameters modify the physicochemical, nutritional, and rheological properties of masa and tortilla.During nixtamalization due to the thermo-alkaline process, there is a Van der Walls force interaction between starch and Ca ++ ions