Lentil protein: impact of different extraction methods on structural and functional properties.

Plant proteins with improved solubility, foaming, and emulsifying properties are required to meet the demand for plant-based foods. This study evaluated the influence of alkaline extraction combined with enzyme- and ultrasound-assisted extraction on lentil protein structure and functionality. Enzyme- and ultrasound-assisted extractions were not capable of increasing the protein yield compared to alkaline extraction alone. However, the purity of isolated protein was dependent on the extraction process, ranging from 82.7% to 90%. Although the molecular mass, zeta potential profiles, and denaturation temperature were not dependent on the extraction method, the enthalpy of denaturation for protein obtained solely by alkaline extraction was significantly lower than that for assisted processes, indicating that protein denaturation is caused by an alkaline process. Changes in protein structure were also suggested by solubility analyses that showed that lentil proteins obtained by enzyme-assisted and ultrasound-assisted extraction have better solubility at pH 7 when compared to alkaline extraction alone. The surface activity of lentil protein was evidenced by interfacial and surface analysis, and it was influenced by the extraction process applied. We demonstrated that combining alkaline extraction with assisted processes, especially ultrasound technology, results in concentrates/isolates with higher solubility as compared to ones obtained solely by the traditional alkaline method, even though the choice of extraction method should depend on the desired functionality.

The effect of enzymatically treated ripe banana flour on the sensory quality and glycemic response of banana-wheat flour composite muffins.

Banana are the most consumed fruit worldwide, due to their good flavour and nutritional characteristics; however, when the banana is very or over ripe, the acceptability by the consumer decreases, and in many cases the fruit must be discarded. An alternative to consume these fruits and revalue these discards is their use as a food ingredient. The presence of bioactive compounds gives added value to this type of ingredients; therefore, using methods, such as enzymatic treatment, that increase their presence is of great interest. In this work a commercial pectinase (Viscozyme L) was applied in a flour produced from whole overripe banana; then, the treated flour was used to elaborate a baked product. The aim of this work was to evaluate the effect of the incorporation of an enzymatic treated overripe banana (Musa cavendishii) flour in the sensory evaluation of muffins and, to stablish if the consumption of this food produce an effect on glycaemic response against a control food. The enzyme application produces an increment of 52% of antioxidant activity with a value of 12,791.6 µmolTE/100 g, and a presence of 4.5% RS instead 3.5% in non-treated flour. The sensory evaluation study was conducted with 4 products, using an untrained panel; selecting a muffin with 50% of wheat flour replaced with the banana treated one. This one contains 9.49% of dietary fibre. The glycaemic response study was conducted with 20 healthy volunteers, using as control a 100% wheat flour product, non-observing significant differences between both products. This work contributes to the knowledge about the potential use of a food discard as an ingredient of a food of massive consumption.

Fructooligosaccharides synthesis by highly stable immobilized ß-fructofuranosidase from Aspergillus aculeatus.

The enzymatic synthesis of fructooligosaccharides (FOS) was carried out using a partially purified ß-fructofuranosidase from the commercial enzyme preparation Viscozyme L. Partial purification of ß-fructofuranosidase from Viscozyme L was done by batch adsorption using ion-exchange resin DEAE-Sepharose, showing a 6-fold increase in specific activity. The biocatalyst was then covalently immobilized on glutaraldehyde-activated chitosan particles. Thermal stability of the biocatalyst was evaluated at 50 °C and 60 °C, being around 100 times higher at 60 °C when compared to the free enzyme. The immobilized biocatalyst was reused 50 times for FOS production (100 min per batch at 50 °C and pH 5.5) without significant loss of activity. The average yield (grams of FOS per grams of initial sucrose) was 55%. The immobilization process combined with partial purification method resulted in a derivative with activity of 1230 Ut/g, which is among the best for FOS production.