Packaging environmental factors

The primary appHcation for barrier polymers is food and beverage packaging. Barrier polymers protect food from environmental factors that could compromise both taste and shelf life. They also help retain desirable flavors and aroma. Barrier polymers are also used for packaging medical products, agricultural products, cosmetics, and electronic components and in moldings, pipe, and tubing. 

The stability of finished pharmaceutical products depends, on the one hand, on environmental factors such as ambient temperature, humidity and light, and, on the other, on product-related factors, e.g., the chemical and physical properties of the active substance and of pharmaceutical excipients, the dosage form and its composition, the manufacturing process, the nature of the container-closure system and the properties of the packaging materials. 

PCL -OCH CH CH CH CH CO-ln) is a partially-crystalline polyester that is biodegraded by microbial lipases and esterases. The plastic is made from petrochemical feedstocks. It has too low a melting point (60°C) to be useful in any packaging applications. Higher aliphatic polyesters such as poly(butylene succinate) (PBS) (-0(CH2) OC(CH2)2CO-)n and poly(ethylene succinate) (PES) (-OCCH l OOCCCH l CO-) are also biodegradable at a rate that depends on environmental factors (Kasuya et al., 1997). They have higher melting points of 112-114°C and 103-106°C, respectively, and the properties compare well to those of polyolefins. As succinic acid can be derived from plant sources, the polysuccinates can be potentially a bio-based polymer. 

For materials for the manufacture of food packaging, disposable products, it is advisable the use of biodegradable polymers, which retain only the performance during the period of consumption, and then undergo a physicochemical and biological transformations under the influence of environmental factors, and easily incorporated into natural metabolic processes bio systems. 

Fermenter cultures are undoubtedly more productive, and give more repro-ducible results than the spinner systems which lack control units tor environmental factors. However they are expensive to purchase, need special facilities, and are for the more expert cell culture practitioner. Nevertheless the smaller laboratory model packages are a worthwhile investment where gram quantities of mAb arc needed, especially where the possibility of a current or hiture market application is envisaged. 

There are many factors that lower nutrient availability in packaged and stored foods. Environmental factors such as the presence of oxygen and light, or processing variables such as temperature, time, pH, and oxidizing and reducing agents affect the stability of nutrients like amino acids and vitamins (Borenstein et al. 1990, Harris 1977). Table 17.6 summarizes the susceptibility of hydrosoluble and liposoluble vitamins to these factors. 

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