Role of oxygen absorbers in food as packaging material, their characterization and applications.

To preserve the environment and to prevent the damage caused by packaging materials, the development of biodegradable, organic, and nano-active films for packaging is progressively being accentuated. As the demand for getting fresh and preservative-free food is increasing, an improved level of clarity and stability for consumers about the packaging is required. Presently, oxygen scavengers are used in the form of films, sachets, powders, or as part of the packaging material itself along with other means of preservation such as the use of chemicals, reduced water activity, pH, multilayer composite material, and or vacuum or modified packaging. Today's current demand increases their incorporation directly into the packaging material rather than being a part of the food itself. The present review, therefore, is based on the availability of types of natural sources of oxygen scavenging systems like antioxidants, and nano iron, and their possible scope of use in the food packaging industry.

Avaliação do volume de oxigênio absorvido por sachê absorvedor de oxigênio em diferentes temperaturas e umidades relativas / Evaluation of the amount of oxygen absorbed by oxygen absorbers at different temperatures and relative humidities

O uso de absorvedores de oxigênio em embalagens de produtos alimentícios acondicionados tem apresentado uma demanda crescente. Assim, o conhecimento da eficiência desses absorvedores em diferentes condições de umidade relativa e temperaturas definidas, são de fundamental importância. Portanto, foram determinadas equações para predizer o volume absorvido de oxigênio para as temperaturas de 10±2 ºC e 25±2 ºC, dependendo da umidade relativa na faixa de 75 por cento a 85 por cento e da taxa de permeabilidade a oxigênio da embalagem. Para a temperatura de 25±2ºC a equação é: V = -32,770+10,440*UR-104,385*ln(TPO2), com um R² = 0,9151. Para a temperatura de 10±2ºC a equação é: V=107,321+6,221*UR-105,166 ln(TPO2) com um R² = 0,8729. Dessa forma, o tempo de atividade do sachê pode ser determinado pela equação T = (V-Vi) / (TPO2*A). Utilizando essas equações e, considerando uma embalagem de área 0,05m² por face, com uma permeabilidade de 8,63 cm3.m-2.dia-1, uma umidade relativa de 80 por cento e o volume de oxigênio inicial dentro da embalagem de 2,5 mL, após o envase, o tempo de atividade do sachê quando armazenado a 10±2ºC foi de 435 dias e a 25±2ºC de 666 dias.

Oxygen absorbers have been presenting a growing demand for application in food packaging. Thus, it is important to know the efficiency of those absorbers in different relative humidity and temperatures. Therefore, equations were developed to predict the volume of absorbed oxygen at 10±2 ºC and 25±2 ºC, according as the relative humidity ranging from 75 percent to 85 percent and the oxygen transmission rate through the package. At 25±2ºC the equation was V = -32,770+10,440*RH-104,385*ln(O2 TR), with R² = 0,9151. At 10±2ºC, V=107,321+6,221*RH-105,166 ln(O2 TR) with R² = 0,8729. As a consequence, activity time for the oxygen absorbers can be calculated with the following equation: T = (V-Vi) / (ln(O2 TR*A). Using these equations and considering a packaging area of 0,05m² for each face, oxygen transmission rate of 8,63 cm³.m-².dia-1, relative humidity of 80 percent and an initial oxygen volume inside the package of 2,5 mL, absorber activity times when stored at 10±2ºC and 25±2ºC were 435 and 666 days, respectively.