Upcycling Food Chain Side Streams into Wholly Biobased Surfactants

The production of food entails the formation of a significant amount of side streams. In particular, the meat industry produces fatty acids, while sugars such as glucose and maltose are byproducts of the cereal one. On the other hand, there is a growing demand for more sustainable surfactants, either produced through biotech methods or using renewable raw materials. Here we report the synthesis of amphiphilic glucose and maltose polyesters (BGE and BME). A two-step process involving lipophilization of sugar through formation of an acetal (glycoside) is followed by esterification using sulfonic acid resins as catalysts. The commercial Lewatit GF-101 provided the best performances in the esterification step as far as the conversion is concerned, that is, 57% and 70% for n-butyl d-glucoside (BG) and n-butyl d-maltoside (BM), respectively, along with the highest degree of polyesterification, that means up to 87% for BGE and 78% for BME. The resulting esters exhibit interesting surfactant properties and are capable of forming stable emulsions. As these surfactants are fully biobased and can be derived from a side stream of the agri-food industry, they represent a sustainable alternative, aligning well with circular economy principles.