At the beginning of the 20th century, proteins were used to produce edible packaging and materials. Later the invention of “synthetic polymers” in 1960 led to the abandonment of protein materials for nearly 30 years, but an increasing number of research programs at academic and industrial levels since 1980 resulted in interest in the usage of field crops for renewable and biodegradable materials for nonfood applications. Proteins are generally composed of a linear combination of the 20 naturally occurring L-α-amino acids (see Fig. 7.1) and are thereby polyamides [1]. Amino acids are classified on basis of the chemical groups that could interact as nonpolar amino acids (Glycine ↔ Tryptophane), ionized polar amino acids (Glutamic acid ↔ Arginine), nonionized polar amino acids (Threonine ↔ Histidine), and amino acids able to form –SS– bond (Cysteine) [1]. The polymerization of the amino acids occurs through the formation of an amide linkage between the carboxyl group of the given amino acid and the amino group of the next amino acid, with the resultant elimination of a molecule of water. This amide linkage is more commonly called a “peptide bond” and proteins are “polypeptides.” The molecular basis for the enormously diverse functions of the proteins is the significant diversity of their building blocks. The chemical nature of the 20 natural amino acids is extremely versatile. The side chain of the amino acids can be either negatively or positively charged, polar, aliphatic (branched or unbranched), or aromatic (substituted or non-substituted). It may include various functional groups such as thiol, amine, hydroxyl, carboxyl, phenyl, and amide groups. Furthermore, the properties of this biopolymer are a result of the amino acid sequence, that is, the linear arrangement of the building blocks, rather than the composition of the protein. Two proteins with the very same amino acid composition may be completely different in their folded state and molecular properties [2].