Pineapple (Ananas comosus) is the most processed tropical fruit generating high quantity of by-products. These by-products represent 25%–35% of the pineapple fruit, being the rind and the core the predominant ones [30]. Pineapple rind and core have a high content of compounds with antioxidant activity, which give them a huge potential concerning their valorization in the cosmetics industry [31]. By using ultra-high performance liquid chromatographic (UHPLC) method, it was determined the presence of eight different carotenoids (α-carotene, β-carotene, β-cryptoxanthin, lutein, lycopene, neoxanthin, violaxanthin and zeaxanthin) and two vitamins (A and E) in the pineapple rind and core, and the effect of Ultraviolet C (UV-C) radiations on these compounds was evaluated [32].
The ultra-violet radiation at a wavelength of 190–280 nm (UV-C) is one of the main sustainable sanitation techniques of fruits, it is an environment friendly technique, relatively inexpensive. It also induces stress in the plant cells, can promote the biosynthesis of carotenoids and vitamin C, and could give an added value to the by-products [33]. On this basis, it was confirmed that the level of L-ascorbic acid in the pineapple rind was higher compared with its level in the whole fruit and it was shown that UV-C radiation increased the L-ascorbic acid content in the rind. It was also established that, among the carotenoids, the most abundant was β-carotene, the carotenoid with the highest pro-vitamin A activity, whose concentration also increased in the rind after UV-C radiation exposure [32].