ABSTRACT
Paper is one of the packaging materials that presents a biodegradable character, being used in several areas; however, its barrier properties (gases and fat) and mechanics are reduced, which limits its application. Coating papers with synthetic polymers improve these properties, reducing their biodegradability and recyclability. The objective of this work was to develop and characterize coated paperboard, using the tape casting technique, with different ratios of film form agar-agar/chitosan (AA:CHI, 100:0, 50:50, and 0:100) and different numbers of coating layers (operating times for application of 14.25 min and 28.5 min for one and two layers, respectively). A significant reduction in water absorption capacity was found by applying a 0:100 coating (approximately 15%). Considering all coating formulations, the water vapor permeability reduced by 10 to 60% compared to uncoated paperboard, except for two layers coated with 0:100. The tensile index (independent of AA:CHI) was higher in the machine direction (22.59 to 24.99 MPa) than in the cross-section (11.87-13.01 MPa). Paperboard coated only with chitosan showed superior properties compared to the other formulation coatings evaluated.
ABSTRACT
Abstract The objective of this study was to evaluate the behavior of active compounds concentration present in the industrial by-product of acerola during drying using convective dehydration at 40, 50 and 60 °C. For this, flavones and flavonols, total proanthocyanidins, vitamin C, total phenolic content and antioxidant capacity as function of drying time were determined. The drying data were adjusted using the models of Page, Lewis, Henderson & Pabis, Modified Page and Logarithmic. In relation to the applied models, Page model presented the best fit. Acerola by-products dried at 40 °C showed higher concentrations of active compounds and higher antioxidant capacity. Although the drying process provoked changes in concentration of the active compounds, in the studied temperature range, significant concentrations of those bioactive compounds were observed. Thus, acerola by-product may present potential for application in different foods.
