CONICET | Buscador de Institutos y Recursos Humanos

Enzymatic technology is the primordial interest for the food biotechnology, because, among others, their properties as quality improvers of products like gluten free bread. Currently, a product that can mimetic the gluten properties has not been found. Therefore, in this work, the extraction and fractionation of enzymes from Glabrous canary seed (CDC-María variety) was perform. The enzymatic extracts were used to replace gluten. The enzymatic extraction process was carried out with a specific protein buffer solution. Subsequently, a fractionation using an isoelectric point precipitation process was performed. For this, a pH adjusting of the solution at pH 4.5, 5 and 5.5 was implemented. Subsequently, the lyophilization was used as preservation method. The effects of the drying process on the effectivity of enzymatic fraction (EF) as improver of gluten free bread was evaluated. Lyophilized EF were added at concentrations between 0.5 to 1% (w/w). The results were compared with a control sample without EF addition. The volume increase percentage and aeration percentage of the baked product were calculated from the images taken from nine slice of bread per each formula. Texture profile was studied with a TMS-TOUCH (Food Technology Corporation, DASTEC) texture analyzer during a period of three days. Shelf life time and hardening speed of bread was calculated. The addition of EF obtained at pH 4.5, pH 5 and pH 5.5 without lyophilized generated a significant statistically decrease in the firmness and hardening speed with respect to the control sample. The highest reduction of this parameters were obtained for the sample with addition of the EF obtained at pH 5.5 (4.65±0.32 N/día) with respect to the control sample (8.34±0.48 N/día). The addition of EF at pH 5.5 allowed obtaining the highest values of volume increase percentage and aeration percentage with respect to the control sample, obtained a rise of 33.88% and 21.2%, respectively. Therefore, the EF obtained at pH 5.5 was selected as the optimum formula. The addition of this lyophilized fraction at a concentration of 0.75% (w/w) allowed to obtain the lowest firmness value and the highest volume increase percentage and aeration percentage with respect to the control sample. However, from the second day of storage a progressively decreases of the firmness was observed. This may be due to a loss of integrity of the matrix. Besides, the addition of this EF generated a statistically significant increase in the hardening speed with respect to the control sample (19.62 ± 0.98 N/day). The behavior of the samples with EF with and without lyophilization presented important differences. This may be due to the lyophilization process that probably caused the denaturation or loss of activity of some enzymes of the EF, generating this negative effect on the sample. Therefore, the use of the EF obtained at pH5.5 without lyophilization, generated significant improvements in the final characteristics of the gluten-free breads. In subsequences studies, the effects of different lyoprotectant agents will be investigated. This will allow obtaining an adequate preservation of its enzymatic activity.