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A mathematical model for a co-current moving bed heat exchanger (MBHE) is presented. The bed is diluted and composed of spheres of uniform radius which are transported by a dragging fluid in plug flow. The gas-solid mixture is heated indirectly by a flue gas, which flows in a jacket around the MBHE. Intraparticle temperature gradients and thermal losses to the external environment are considered. The model is solved analytically by the Self-Adjoint Operator method (SAO) and numerically by a combination of the Finite Analytical (FA) and the Finite Difference (FD) method. The results show excellent agreement and the comparison with experimental data validates the model, enabling its use in the design and analysis of MBHEs for which thermal losses are a relevant factor. MBHE effectiveness is defined, and it is shown - for a selected case - that the addition of 5.0 cm thick glass wool raises it by 25.5%. [ABSTRACT FROM AUTHOR]

The interest in producing renewable polymers from natural resources is considerably increased as the need for the reduction of the amount of plastic waste in the environment becomes urgent. Biopolymers are considered as an alternative raw material for the development of biodegradable packaging to plastic produced from petroleum. Starch, a renewable biopolymer consisting of amylose and amylopectin, is the most commonly used agricultural raw material for edible film manufacturing because it has low cost, easy to handle and totally biodegradable. In order to maintain the quality of foods, it is necessary to select the correct materials and appropriate technologies for the production of the packaging. Current trends include the development of packaging that interacts with food, called active biofilms or active packaging. Nanocomposites with antimicrobial function are highly useful for the minimization of the growth of contaminant microorganisms during the processing or storage of food and thereby the extension of shelf-life and improvement of food safety. Thus, this work aims to review the literature to identify the main components used in packaging with nanoparticles and the results in food preservation. For this purpose, a bibliographic survey of the last 5 years was carried out in the databases of Scielo, Science direct, Google academic and Periodicals CAPES, with the following indexers: nanocomposites, nanotechnology, active packaging, and antimicrobial packaging. Some studies demonstrated that metal oxide nanocomposites in packaging provide enhances polymer barrier properties, making the material stronger, more flame resistant, with better thermal properties and having favorable surface wettability and hydrophobicity. Studies have shown that silver nanoparticles have antimicrobial activity against Gram-negative and Gram-positive bacteria and fungi. Also, chitosan nanostructures, a natural composite, have wide antimicrobial effects. Some studies have focused on antimicrobial effects of nanostructures combining chitosan and other antimicrobial agents as carvacrol, oregano and thyme essential oil. It was observed that chitosan nanocomposites combined with layered silicate were significantly more effective against Staphylococcus aureus and Escherichia coli than both pure. Packaging that increases the shelf-life of perishable food while reducing food waste is a sustainable opportunity for innovative technology. [ABSTRACT FROM AUTHOR]

Abstract: The occurrence of aflatoxin M1 (AFM1), ochratoxin A (OTA), and deoxynivalenol (DON) in human milk and their correlation to the lactating donors dietary habits from Southern Brazil were investigated. Milk samples were collected from 86 nursing mothers who were also interviewed through a Food Frequency Questionnaire (FFQ). The occurrence of AFM1, OTA, and DON in the human milk samples was evaluated by liquid chromatography tandem mass spectrometry (LC‐MS/MS) and correlated with the FFQ data. The analysis of the FFQs revealed a high intake of foods susceptible to mycotoxin contamination, such as wheat flour and its derivatives, bovine milk, and coffee which had habitual consumption reported by 71, 50, and 43% of the participants, respectively. AFM1, OTA, and DON were not detected in any sample of human milk, even though the results obtained by LC‐MS/MS suggest a possible occurrence of DON in four samples (>LOD: 2.5 ng/mL;