Concreto celular de diferentes densidades: efeito da goma xantana como estabilizador de espuma e de fibras de polipropileno

Abstract

With the growing demand for materials that do not harm the environment, biopolymers emerge as an alternative to replace conventional plastics. In addition, the need for new technologies in the field of food safety as well as the use of agro-industrial waste as a source of raw material has drawn attention in studies carried out in recent years. Thus, the objective of the present work was to produce and characterize a colorimetric sensor using k-carrageenan as a biopolymer, glycerol as a plasticizing agent and incorporating jabuticaba epicarp extract (Plinia cauliflora), in order to identify observations of pork meat via pH change. The extract contains the bioactives and was produced by the maceration technique and characterized for the content of total phenolic compounds, antioxidant activity and total anthocyanins, presenting results of 192.44 ± 2.42 mgGAE.g-1 ; 78.10 ± 2.34%; 4136.13 mg.100 g-1, respectively. In high performance liquid chromatography it was possible to observe that the phenolic compound in greater abundance in the extract was cyanidin-3- glucoside. The sensors were prepared in the form of films using the casting technique. The incorporation of the extract in the composition of the film increased the film thickness from 0.05 mm to 0.14 mm, the water vapor permeability from 4.47x10-10±1.48x10-11 Kgm-1Pa1s-1 for 9.99x10-10±8.46 Kgm-1Pa-1 s -1, a breaking strength of 1.01±0.14 MPa to 4.65±0.64 MPa and also an elongation capacity of 5.11±0.50% to 36.02±0.29%. The results indicated that when used to monitor pork storage, there was a change in color in the sensor as the pH of the meat increased, as expected, where the change was evaluated via the Cielab scale. The pH variation was from 5.82±0.01 to 6.81±0.02 during 9 days of analysis and difference in color in the sensor (ΔE) of 13.40, this difference being considered by the literature as easy to perceive by the eye human. Even so, it was possible to quantify the nitrogen compounds released by pork during storage. The results indicated a gradual increase, initially from 0.063±0.02 mg/g to 0.94±0.02 mg/g of volatilized NH3. Thus, the biopolymer film obtained from k-carrageenan and jabuticaba epicarp extract presented characteristics developed for application as a colorimetric sensor indicative of manipulation of pork via pH alteration. Keywords: carrageenan, intelligent, monitoring