## 2 Carotenoids in Fresh and Processed Food: Between Biosynthesis and Degradation  
The aim of this Special Issue was to group the most recent and relevant research in relation to the aforementioned topics regarding carotenoids in food into a single document. Subsequently, the possibility of publishing a book with the contributions of all authors has been assessed. There were six papers submitted to this Special Issue, and five of them were accepted. In the following paragraphs, a summary of these papers with their most relevant findings is presented. The first paper [3] deals with the protection of \(\beta\)-Carotene from photodegradation. The authors of this work showed how \(\beta\)-Carotene degrades rapidly in a 2% oil-in-water emulsion, made from food-grade soy oil with 7.4 mg \(\beta\)-carotene/mL oil, during storage and when exposed to light. However, the addition of clove oil (2.0, 4.0, or 8.0 \(\mu\)L/mL ofemulsion) prevented the photodegradation of \(\beta\)-carotene, regardless of the ratio between clove oil and \(\beta\)-carotene in the concentration range studied. Since plant phenols have been demonstrated to efficiently regenerate carotenoids from their initial photooxidation products, the authors concluded that the observed regeneration of \(\beta\)-carotene was due to eugenol, the main plant phenol of clove oil to occur in the oil-water interface. Therefore, clove oil in low concentrations may find use as a natural protectant of provitamin A in enriched foods during retail display. The second paper [4] presented how two typical plant hormones, namely salicylic acid (SA) and methyl jasmonate (MeJA), were able to regulate the accumulation of flavonoids (i.e., eriocitrin, narirutin, and poncirin) and carotenoids (i.e., \(\beta\)-cryptoxanthin) in the juice sacs of Satsuma mandarin in vitro. The results showed that SA treatment was effective in enhancing the contents of eriocitrin, narirutin, poncirin, and \(\beta\)-cryptoxanthin, whilst MeJA treatment inhibited these compounds accumulation in the juice sacs (\(p<0.05\)). Moreover, gene expression analysis confirmed that the changes of flavonoid and carotenoid contents were highly regulated at the transcriptional level. In particular, a transcriptional factor CitWRKY70 was identified in the microarray analysis, which was induced by the SA treatment while being suppressed by the MeJA treatment. Since the change in the expression of CitWRKY70 was consistent with that of flavonoid and carotenoid biosynthetic key genes, this finding indicated that CitWRKY70 might be involved in the regulation of the investigated compounds content in the juice sacs of citrus fruit in response to SA and MeJA treatments. In the third article, [PERSON] et al. [5] studied the influence of light at different wavelengths (white light at 380-780 nm, UVA at 340 nm, blue light at 440 nm, and red light at 630 nm) and pulsed electric field (PEF) at different strength (1, 2.5 and 5 kV/cm) on the content of carotenoids (i.e., lutein, zeaxanthin, and \(\beta\)-carotene) in red clover sprouts. The experiment was carried out in a climatic chamber with phytotron system under seven growing conditions differing in light-emitting diode (LED) wavelengths and PEF strength applied before sowing. Lutein was found as the dominant carotenoid in germinating red clover seeds, with content varying from 743 mg/kg in sprouts grown in red light to 888 mg/kg in sprouts grown in blue light. Blue light treatment during the red clover sprouts growing had the most beneficial effect in enhancing carotenoids content up to 42% in \(\beta\)-carotene, 19% in lutein, and 14% in zeaxanthin. An increase of \(\beta\)-carotene (8.5%) and lutein (6%) amount was also obtained with white light without PEF pre-treatment; conversely zeaxanthin decreased by about 3.3%. Therefore, the authors concluded that PEF pre-treatment may increase mainly the content of \(\beta\)-carotene in red clover sprouts.