Barley ß-glucans extraction and partial characterization.

Barley is rarely used in the food industry, even though it is a main source of ß-glucans, which have important health benefits and a technological role in food. This work evaluated the humid extraction of barley ß-glucans and partially characterized them. The extraction was studied using surface response methodology with both temperature and pH as variables. The extracted ß-glucans were characterized by chemical and rheological analysis, infrared spectroscopy and scanning electron microscopy. The effect on extraction of linear and quadratic terms of pH and temperature corresponding to the regression model was significant, and we obtained a maximum concentration of 53.4% at pH 7.56 and temperature 45.5°C, with protein and mainly starch contamination. The extracted ß-glucans presented a higher apparent viscosity than the commercial ones, the behavior of the commercial and extracted samples can be described as Newtonian and pseudoplastic, respectively. The results of infrared spectroscopy and scanning electron microscopy were characteristic of commercial ß-glucans, indicating that this method is efficient for extracting ß-glucans.

Chemical characterization of candy made of Erva-Mate (Ilex paraguariensis A. St. Hil.) residue.

The aim of this work was to evaluate the chemical properties of the residues from erva-mate processing and also to determine the candy-making performance with addition of residues from erva-mate on consumers' acceptance and purchase intent of this new product. The candies containing different amounts of mate powder were evaluated through overall acceptability test and purchase intent. Mate powder showed high contents of dietary fiber, total ash, and total polyphenols. The total dietary fiber content of the mate candies ranged from 5.7 to 6.29% on a dry matter basis. Supplementation with mate powder caused significant increases in polyphenol and mineral contents of mate candies. The incorporation of mate powder increased the hardness of the candies and produced desirable results in their nutritional characteristics. The sensory tests indicated that mate candies were acceptable and approved in relation to purchase intent.