The aim of this work was to perform the screening of microorganisms, previously isolated from samples of agro-industrial waste and belonging to the culture collection of our laboratory, able to produce polygalacturonases (PG). A total of 107 microorganisms, 92 newly isolated and 15 pre-identified, were selected as potential producers of enzymes with PG activity. From these microorganisms, 20 strains were able to synthesize PG with activities above 3 U mL(-1). After the kinetic study, the enzyme activity was increased up to 13 times and the microorganism identified as Aspergillus niger ATCC 9642 and the newly isolated W23, W43, and D2 (Penicillium sp.) after 24 h of fermentation led to PG activities of 30, 41, 43, and 45 U mL(-1), respectively. The RAPD analysis demonstrated that the selected strains differs genetically, indicating that no duplication of strains among them in the experiments for polygalacturonases production was verified.

This paper aim to evaluate the ultrafiltration (UF) process for constituents recovery from whey. Sequences of factorial designs were performed by varying temperature (5 to 40°C) and pressure (1 to 3 bar), to maximize the proteins concentration using membrane of 100kDa in dead end system. Based on the best result new experiments were performed with membrane of 50kDa and 10kDa. With the membrane of 50 the protein retention was about 3 times higher than the membrane of 100kDa. The concentrated obtained by UF membrane of 10kDa, 10°C and 2 bar in laboratory scale showed a mean protein retention of 80 %, greater protein solubility, emulsion stability and the identification of β-lactoglobulins (18.3 kDa) and α-lactalbumin fractions (14.2kDa). Therefore, the use of membrane of 100 and 50kDa are became a industrially recommendable alternatives to concentration of whey proteins, and/or as a previous step to the fractionation of whey constituents using membrane ≤10kDa, aiming at future applications in different areas (food, pharmaceutical, chemical, etc.).

The aim of this work was to evaluate the effect of different package conditions on the characteristics of Toscana fresh sausage stored for 150 days under freezing. The analyses of lipid oxidation, moisture, pH, acidity, water activity, and counting of psychotrophic microorganisms were carried out along with the storage time for each package (low-density polyethylene with and without vacuum and oxygen permeability of 500 cm 3 O 2 /m 2 day atm at 23°C; nylon polyester with and without vacuum and permeability of 100 cm 3 O 2 /m 2 day atm at 23°C; and formal copolymer of ethylene and vinyl alcohol with and without vacuum and oxygen permeability of 5 cm 3 O 2 /m 2 day atm at 23°C). Results showed that from 60 days of storage, the samples stored using polyethylene without vacuum and nylon 100 cm 3 O 2 /m 2 day atm, without vacuum, presented a slight rancidity flavor, statistically different (p<0.05) from the other tested ones. After 151 days of storage, a relationship between 2-thiobarbituric acid reactive substances analysis and sensory characteristics could be observed. In this case, the packages without application of vacuum presented higher values in the sensory and oxidative rancidity analyses, configuring flavor of slight to moderate rancidity.

No abstract

The packaging protects food from actions of external agents, from alterations and contaminations, in addition to adulteration. Edible films are structures produced from biopolymers, which can replace non-biodegradable packaging. These films have been formulated with naturally polymers of polysaccharides, lipids and proteins, isolated or combined with each other. Edible films produced with polysaccharides and proteins are transparent and flexible, although proteins films are less resistant. They act as a barrier, protecting food and increasing shelf life. Additionally, they can carry antimicrobial and antioxidant compounds, being called active films. The antioxidant power is proportional to the amount of the compound added. Natural extracts such as green tea, cloves, ginger and others can be incorporated into the films, wich could improving the mechanical properties of the films and the characteristics of the food. The use of active edible films has been evaluated in the meat industry as an alternative packaging. This review aims to address the use of edible films added with vegetable compounds, with antimicrobial and antioxidant activity, applied to meat products.