# Applications of Plant Polymer-Based Solid Foams: Current Trends in the Food Industry
## 2 Food Industry Applications
### Plant Polymer-Based Foams as Edible Materials
#### 2.1.5. Starch
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Plant** & **Study** & **Type of Foam** & **Foam Characteristics** & **Polymer Characteristics** \\
**Polymer** & **Study** & **Type of Foam** & **Foam Characteristics** & **Polymer Characteristics** \\ \hline
**Polysaccharides** & & & \\ \(\bullet\) & Foam made from thermoplastic & & TPS foam showed lower \\  & & & absorption with improved water \\  & & thermoplastic & resistance. \\  & & starch (TPS). TPS & The foam microstructure showed a \\  & & was made by & sandwich-type structure, more or \\  & acetylation and & & less dense outer layers, and a more \\  & & esterification with & compact cellular structure than \\  & & maleic anhydride & pure TPS foam. Foams with more \\  & & of potato & modified starch expanded more \\  & & starch [44] & and became more porous \\  & & & Foams show the typical sandwich \\  & & & structure, with denser outer layers \\  & & & with small cells and an inner layer \\  & & & with larger and more expanded \\  & & & cells. Silylated starch foams have a \\  & & & more compact structure with \\  & & & thicker outer layers than \\  & & & traditional starch foams. They \\  & & & become mechanically more \\  & & & resistant and have less water \\  & & & absorption capacity \\  & & & \\ \(\bullet\) & Foam made from & & Foams with essential oils had \\  & & & small cracks and holes. They \\  & & & displayed a more irregular but \\  & & & denser surface due to starch-lipid \\  & & & complexes forming during the \\  & & & thermal process. Starch and \\  & & & essential oils also formed strong \\  & & & interactions, resulting in \\  & & & starch–essential oil complexes in \\  & & & the foam layers. Thus, essential oil \\  & & & drops were trapped within the \\  & & & starch granules. Foams presented \\  & & & a sandwich structure with two \\  & & & well-defined layers and the \\  & & & presence of air cells. Essential oil \\  & & & addition and type also affected the \\  & & & layer thickness and the air cell size \\  & & & between the foams. \\  & & & \\  & & & The foam has a sandwich type \\  & & & structure with dense outer skins \\  & & & containing small cells comprising \\  & & & the surface of the foam. The \\  & & & interior of the foam has large cells \\  & & & with thin walls. Adding over 50\% \\  & & & corn fiber, foamed trays contain \\  & & & few small cells in their outer skin. \\  & & & In the interior the cells are smaller, \\  & & & and the foam becomes denser. \\  & & & \\  & & & Trays containing only potato and \\  & & & PVA had thinner skins and larger \\  & & & cells with thicker walls. The outer \\  & & & skin of trays containing corn fiber \\  & & & show compressed and \\  & & & bounded fibers \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Plant** & **Study** & **Type of Foam** & **Foam Characteristics** & **Polymer Characteristics** \\ \hline \multirow{6}{*}{Corm Starch} & & & \multicolumn{1}{c}{Starch foams were very} & \multirow{2}{*}{Corn starch is, in general terms, similar to other cerealarches, and in specific properties has greatest similarity to its genetically closely related cousins, sorghum and the millets. Normal corn is composed of amylose and amylopectin. It is usually composed of 27\% amylose and amylopectin. It is usually composed of 27\% amylose and amylopectin [49]. However, this amylose/amylopectin ratio varies slightly with different corn varieties, environmental and soil conditions. Waxy maize consists of amylopectin only, and high amylose corn contains amylose as high as 70\% [50] \\ \cline{1-  
\begin{table}
\begin{tabular}{c c c c} \hline
**Plant** & **Study** & **Type of Foam** & **Foam Characteristics** & **Polymer Characteristics** \\ \hline \multirow{6}{*}{\(\bullet\)} & & & Foams present dense and \\  & & & homogeneous external walls, with \\  & & & small, closed cell structure.