*2.8. Oils' Saponification*

The fatty acids of the EVO and NEFO oils were totally (0% of non-neutralized fatty acids) and partially (5% of non-neutralized fatty acids) neutralized and four different types of soaps were obtained:


The quantity of NaOH used for the production of the described soaps was determined by SV. The quantities of NaOH used and the SV values are shown in Table 1.

A classic saponification procedure was applied for soap produced with EVO oil, while for the saponification of NEFO oil it was necessary to make changes with respect to the standard procedures reported by Spitz [7,8].

In 30 mL of deionized water 13.541 g and 13.334 g of NaOH were dissolved to obtain, respectively, the soaps with 0% and 5% of non-neutralized fatty acids (Table 1). Each alkaline solution was mixed with 100 g of oil at a temperature of 35 ◦C. The oil-water mixture was shaken strongly to obtain a semi-liquid consistency. The dough was placed in a mold for the subsequent maturation process [7,8].

The saponification of NEFO oil was carried out by varying the "cold" method. In 30 mL of deionized water 12.864 g and 12.667 g of NaOH were dissolved to obtain, respectively, the soaps with 0% and 5% of non-neutralized fatty acids (Table 1).

Each NaOH solution was added with slow dripping to 100 g of oil in a thermostated system at 20 ◦C with continuous stirring. A warm, semi-solid soap paste formed quickly due to the exothermic acid-base reaction between NaOH and fatty acids. The soap paste was placed in a mold for the subsequent maturation process.

The saponification for EVO oil and NEFO oil was carried out considering the complete neutralization of the fatty acids and the non-neutralization of 5% of the fatty acids using the SV of the oils. The quantity of NaOH used for the production of the different soaps and the SV are shown in Table 1. The soaps were stored in a dark room with low humidity on filter paper to prevent rancidity.

The soaps considered (0% and 5% of non-neutralized fatty acids) are those most produced by industries and most consumed [7,8].
