Multilayer films of beeswax-pectin for water barrier packaging

FLORENCIA CRUCES; MARIA GUADALUPE GARCIA; DARIO DIAZ; NELIO ARIEL OCHOA

Cordoba

Congreso; VI Congreso Internacional de Ciencia y Tecnología de Alimentos (CICYTAC 2016); 2016

Gobierno de la provincia de Cordoba

Growing environmental concerns caused by the accumulation of wastes from non-renewable packaging materials has led to the development of new food packaging materials friendly to the environment. Biopolymers such as, polysaccharides and lipids have been extensively studied in recent years for this purpose. Pectin is an excellent film forming polysaccharide which exhibits good barrier properties to fats and gases however; it is very susceptible to moisture. On the other hand, lipids, like beeswax, exhibit excellent water barrier properties, however, they do not have mechanical and physical integrity required to form films. For these reasons, it is interesting to develop a composite material where each component satisfies a specific function: beeswax reduces the water vapor permeability, and pectin gives the strength and structural integrity to the film. In this work multilayered films composed of pectin and beeswax were prepared in order to be use as food packaging material. The influence of the beeswax content and the distribution of layers in water barrier and mechanical properties were studied. In this work, pectin films (PF) were obtained by dissolving a certain amount of pectin (Sigma Aldrich, low methoxyl) in distilled water. Glycerol (Gly, Biopack ≥ 99.5 %) was added as plasticizer to the polymer solutions. The suspension was casted onto Petri dishes and dried at 60°C overnight. Three different types of multilayer films were obtained through two different techniques: 1) Natural beeswax solution was spread on a preformed PF by using an atomizer; 2) Natural beeswax solution was casted onto a preformed PF. Multilayer films were named as: Beeswax-Pectin-Beeswax (BPB); Pectin-Beeswax-Pectin (PBP) and Beeswax-Pectin-Beeswax-Pectin-Beeswax (BPBPB). Mechanical properties and water vapour permeability (WVP) of the films were determined following the ASTM D 882-02 and the ASTM E95-96, respectively. Results of mechanical propierties, Tensil Strength (TS), Elongation at break (EB) and Young?s Module (E) of multilayer films shows Two effects depending on the number of layers of beeswax and/or pectin in the multilayer films. First, a plasticizing effect of beeswax on BPB film was observed due to the decrease in TS and E, as well as the increase in EB%. Second, a reinforcing effect was observed in PBP film due to the increment in TS and E, while EB% decreased markedly. This reinforcement was attributed to the bilayer of pectin. Finally, BPBPB film showed stronger influence of the two pectin layers than three beeswax layers due to a marked increase in E and a reduction in EB%. Results of WVP values of multilayer films shows a decrease in WVP as the layers of beeswax increased in the films. Interestingly, BPBPB film showed a WVP value 9.7 times lower than that of a control PF.