*1.4.1 Food composition*

Food is a complex compound containing varying amount of components composing of volatile and non-volatile substance is primarily of protein, lipids, carbohydrate and water [21, 22]. These components of food interact with each other and with the wall of packaging materials [23]. These particulate component of food are held

#### *Food Preservation Packaging DOI: http://dx.doi.org/10.5772/intechopen.110043*

together by a chemical bonding such as (i) hydrogen bond (ii) covalent bond (iii) hydrophobic bond/vander waals (iv) physical binding [24] and they disintegrate/ separated at a different petition rate depending on the amount of interaction with micro-molecules in the food matrix. The composition containing fat/oil had major effect on flavor interaction, followed by proteins and polysaccharides and then by disaccharides [4]. Example lipids (fats and oils) determine the physical and sensory characteristics of non-water soluble foods as well as determine their ability to absorbed or loose flavor compounds to or from packaging films. Aqueous and high water foods tend to interact with packaging more than solid or powdered foods therefore very prone to packaging interaction. Increase in food pH also increase the rate of package migration [6], nature and concentration of migrating compound in the food also influences the rate of packaging interaction, example presence of same flavor compound of food on the packaging materials will speed of the rate of scalping process [12]. In nutshell, the selection of packaging for foods should consider the nature of the foods such as; (i) acidity (carbon chain and structure (iii) viscosity (iv) concentration (v) flavor and aroma compound presence (vi) molecular weight of the food (vii) carbon functional group and polarity.

Depending on the food nature, interaction of food with packaging is greatly affected by the food composition, the components of food can either be interactive/migrating (occurs through leaching or volatile system) or non-interactive/ non-migration. Migrating compound in food are usually very reactive, loose and less chemically bonded to the food therefore can easily interact with the packaging film. Migrating volatile aromatic compound in dried foods can easily be loss through either diffusion or evaporation, desorption from product or adsorption on to the product without direct contact with the packaging film. For a leaching migrating food system, components of food interact when they are in direct contact with the packaging film, that is the food (such as fat) components diffuse from the food surface, dissolved on the surface of the packaging and the adsorbed by the packaging film, or by its diffusion from the packaging materials, followed by dissolution and dispersion into the food. High fatty foods leach faster than high fiber foods due to their higher affinity and reduced viscosity.
