Ana N. Rinaldoni

Fractionation of skim milk by an integrated membrane process for yoghurt elaboration and lactose recuperation.

A combined membrane process has been used to fractionate skim milk. Microfiltration and ultrafiltration were employed to obtain concentrates with different protein/lactose ratios depending on the volume concentration ratio to produce protein enriched yoghurt. Nanofiltration has been used for lactose recovery from the ultrafiltration permeate with partial demineralization, while the permeate water of NF can be reused or recycled. Feed, permeate, concentrates and yoghurt have been physicochemical characterized and compared with commercial products. The obtained yoghurts have a smooth aroma and an agreeable taste, the protein content increased up to 50 % and the lactose content decreased approximately 50 % in comparison with commercial yoghurts, while calcium and iron were also increased, leading to a product with special characteristics and high commercial value. Lactose powder has been obtained by lyophilization; the product has good solubility and has 90% purity which can be used in different food preparations or for other applications.

Incorporation of Okara into Gluten-Free Cookies with High Quality and Nutritional Value

Soy products are a source of protein relatively inexpensive and recognized for their high nutritional value and functional properties. Okara is a byproduct from soy milk production. Gluten-free cookies have been developed using okara and commercial manioc flour. Four formulations were developed with different proportions of okara: 50%; 30%; 15%; and 0%. Physicochemical, physical properties, sensory analysis, and nutritional studies were performed. The use of inulin as partial replacement of sugar was evaluated. The incorporation of okara increased protein and fiber content. Furthermore, the hardness of cookies increased while the index of whiteness decreased. From the sensory evaluation, it could be concluded that the cookies presented a great acceptability. The cookies developed in this study have functional characteristics, providing added value to a waste product; furthermore the products were suitable for celiacs with acceptable quality and improved nutrition value.

Quality assessment of dried okara as a source of production of gluten-free flour

BACKGROUND Okara is a by-product of soymilk and of tofu elaboration that is rich in protein, fiber and vegetable oils as a source of gluten-free flour. In order to take advantage of the nutritional characteristics of okara and to be able to determine an appropriate drying methodology, microwave, rotary dryer and freeze-drying were assessed. Furthermore, flour with an enzymatic treatment was characterized as well as its functional, physicochemical, and textural properties. RESULTS The results showed that the physiochemical characteristics of the flour were affected by the drying process, reaching adequate water content, and high protein and fiber content. The freeze-drying process produced clearer flours with porous structure and high water absorption capacity, and with a higher protein denaturation. Okara dried by microwave and rotary dryer exhibited a denser structure with similar functional properties and improved textural characteristics such as firmness and consistency. The microwave-produced flour was darker due to the non-enzymatic browning reactions. The enzymatic treatment employed improved the consistency of the flour. CONCLUSION It was possible to choose the drying process to be applied according to the feasible use of the flour, intended to preserve the favorable nutritional aspects of the okara flour. Based on the results, it can be affirmed that the physicochemical properties and attributes of okara are influenced by the drying process employed. Okara dried by freeze-drying resulted in a better product because it had a low final moisture content and the highest whiteness index. The flour presented a porous structure with high solubility, which is an indicator of potential applications in foods developments.

Process for integral use of blueberry

Abstract Blueberries, rich in anthocyanins, have long been recognized for their health benefits as antioxidant, besides they have been studied for their potential as natural colourants for food or cosmetics. A flow sheet which includes several methods for processing blueberry were performed to obtain different products. Membrane technology was applied, as a non thermal alternative for obtaining a clarified juice in the permeate stream and a blueberry concentrate in the other stream. An inorganic microfiltration membrane Carbosep® was used into a tubular Plexiglas module. The concentrate was dried by freeze-drying at -40°C and 1 bar. With the solids obtained in the pre-treatment and during the filtration of the fruit, jams were elaborated following the usual procedure. Different jam formulations were assayed: i) common grade with the addition of sugar, and ii) reduced calories, using Stevia (rebaudiana Bertoni) as a natural sweetener. The polysaccharide has many healthy properties in treating obesity and high blood pressure. A physical-chemical and sensory analysis of fruits and products has been carried out. The results showed that blueberries’ clarified juice, presented colour, flavor and pleasing appearance, the presence of anthocyanins could be determined. The freeze-dried concentrate was stable, retaining a bright colour similar to the fruit and can be quickly re-hydrated. The manufactured jams showed similar characteristics to commercial products (pH: 3.5; soluble solids: 67.5 °Brix; ash: 7.4 % w/w). The sensory analysis indicated that the formulation with sugar /Stevia: 50-50%, was rated significantly better than mixtures 25-75% or 100% Stevia. The process allows an integrated use of the fruit obtaining products with high nutritional quality.