## 6 Historical and Potential Modern Uses of Acorns in Food
aegips_} & acorn flour/5–15\% & \multirow{2}{*}{Arabic bread} & \multirow{2}{*}{fiber content increase} & [97] \\  & substitution of wheat flour & & & domination of oleic acid, high content of tocopherols (with \(\gamma\)-tocopherol domination), sterols (predominantly \(\beta\)-sitosterol), and phenols & [72] \\ \cline{1-1} \cline{2-5}  & acorn oil & & & \\ \cline{1-1} \cline{2-5}  & acorn flour/5–30\% & \multirow{2}{*}{sponge-fat cake} & \multirow{2}{*}{n.a.} & [98] \\  & substitution of wheat flour & & & \\ \cline{1-1} \cline{2-5}  & acorn flour/15–45\% & & & \\ \cline{1-1} \cline{2-5}  & substitution of wheat flour & & & \\ \cline{1-1} \cline{2-5}  & acorn flour/15–45\% & \multirow{2}{*}{gluten-free biscuits} & \multirow{2}{*}{unicidant activity increase} & [99] \\  & substitution of corn flour & & & \\ \cline{1-1} \cline{2-5}  & acorn flour/25–50\% & \multirow{2}{*}{white yeast bread} & \multirow{2}{*}{white yeast bread} & \multirow{2}{*}{white yeast bread} & [100] \\  
The most popular direction remains the use of acorns in formulating bakery and confectionery products as an enriching ingredient, which has been introduced into contemporary baked goods. Ongoing research seeks to obtain bread, cakes, and pastries in which acorn flour will be a source of bioactive compounds and thus have a positive effect on nutritional value, while at the same time, the characteristics of the finished products will be similar to those made from conventional raw materials [96; 111]. Historical reports and contemporary work on the use of acorns in food production indicate differences not only in the directions themselves for the use of acorns but also in their proper preparation and pre-treatment, primarily to reduce their tannin content. [PERSON] [91] reports that Indians, indigenous peoples of North America, carried out the de-acornization of acorns by mixing them with iron-rich red earth or wood ash. [PERSON] [3] states that in Sardinia, acorn bread was prepared from acorn flour mixed with clay and ash, which may also indicate the use of these ingredients in the de-gorging of acorn raw materials. [PERSON] and [PERSON] [93] presented a procedure for baking acorn bread, in which acorns were previously subjected to roasting and leached in water with the addition of red clay. [PERSON] et al. [4] have prepared a compilation of traditional methods of processing and using acorns in the Mediterranean and the Middle East. Regardless of the region, acorns were subjected to the debittering process, and the steps used and their complexity probably depended on the variety of oak from which the acorns were extracted and the associated concentration of tannins in the raw material. Debittering usually involves roasting (Calabria in Italy), boiling (Iraq, Afghanistan, Algeria, and Syria), or soaking the acorn nuts in cold water (Iran), followed by drying the seeds. Acorn debittering, carried out today, is based on similar methods and processes used in the past, namely leaching tannins in water, drying, or roasting [112; 113; 114]. Greater attention,  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline _Quercus_ Species & **Acorn Form/Amount in Product** & **Food Product Type** & **Specified Nutritional Advantage** & **References** \\ \hline \multirow{4}{*}{_Q. infectoria_} & & & domination of oleic acid, high & \\  & & & content of tooperhools & \\  & & & (predominantly \(\gamma\)-tocopherol), & \\  & & & sterols (predominantly & \\  & & & \(\beta\)-sitosterol), and phenols & \\ \hline \multirow{2}{*}{_Q. persica_} & acorn flour/10\% & \multirow{2}{*}{bread} & \multirow{2}{*}{antiv oxidant activity increase; inhibition of surface molliness} & \multirow{2}{*}{[108]} \\  & substitution of wheat flour & & & \\ \hline \multirow{4}{*}{_Q. rotundifolia_} & \multirow{2}{*}{acorn kernels as raw material} & \multirow{2}{*}{flour} & \multirow{2}{*}{n.a.} & \multirow{2}{*}{[109]} \\  & & & high fiber and lipids & \\  & & & (predominantly unsaturated & \\  & & & fatty acids, especially oleic acid) & \\  & & & content & \\ \hline \multirow{2}{*}{_Q.