## 3 Avocado's Composition in Nutrients and Bioactives
### Avocado Bioactive Compounds
#### 3.2.3 Carotenoids  
Carotenoids and chlorophylls are the main pigments in avocado oils, with lutein and \(\beta\)-carotene being the most common carotenoids of the fruit and pheophytin a and b being the most common chlorophylls, respectively. The terpenoid pigments known as carotenoids range in color from yellow to orange-red and are produced by bacteria, fungi, and photosynthetic organisms. There are two groups of carotenoids: carotenes, which are just hydrocarbons and do not include oxygen, and xanthophylls, which do have the presence of oxygen. By scavenging and neutralizing free radicals, they can function as antioxidants [72]. Beyond their function as naturally occurring colors, carotenoids are beneficial to human health because they function as bioactive substances with provvitamin-A properties (\(\beta\)-carotene and \(\beta\)-cryptoxanthin) and strong antioxidant activity. Similarly, chlorophylls possess antimutagenic and antioxidant properties in addition to being responsible for giving the green coloration, which aids the prevention of degenerative diseases. Notably, because carotenoids have a positive association with antioxidant activity, they can function as defenses against photosensitive oxidation [17; 73; 74; 75; 76; 77; 78].  
Fruits and vegetables' carotenoid content varies depending on ripeness, genetic diversity, and processing techniques [79]. In avocado seeds, the dried sample of the Hass variety had the highest total carotenoid concentration, with 6.47-9.34 mg/kg, as shown in Table 3, while the carotenoids found in avocado were mainly neoxanthin, violaxanthin, neochrome, 9''-cis-neoxanthin, lutein-5,6-epoxide, chrysanthemaxanthin, lutein, zeaxanthin, \(\beta\)-cryptoxanthin, \(\alpha\)-carotene, and \(\beta\)-carotene [15; 80]. Xanthophylls lutein (all-trans-lutein), \(\beta\)-carotene, zeaxanthin, and cryptoxanthin make up about 90% of the carotenoids in avocado. Avocados provide an ideal dietary matrix for increasing zeaxanthin and lutein bioavailability, as these carotenoids are absorbed better when ingested with lipids and entire foods, rather than as supplements. Carotenoids are considered to linger within small intestinal enterocytes, until long-chain fatty acids become available to encapsulate and transfer them via the lymphatic system. Avocados serve an important function in stimulating chylomicron production and delivering lutein throughout the body, making them a good dietary option for increasing zeaxanthin and lutein intake, which improves cognitive health. Moreover, several studies have found a link between lutein and zeaxanthin consumption and beneficial cognitive profiles, particularly among people with obesity or those who are overweight [75; 81].  
In various studies [14; 17; 77; 81], a randomized controlled trial was conducted so as to assess the effect of avocado consumption on cognition in older adults via the intake of a high-lutein-content food source. The results showed that avocado consumption significantly increased serum lutein levels and macular pigment optical density (MPOD) [77]. As result, individuals showed significant improvements in spatial working memory within three months. More particularly, a study by [PERSON] et al. [81] evaluated the effect of avocado consumption on cognitive function in overweight and obese adults using dietary intervention rather than supplementation. Participants aged 25-45 were randomly allocated to either a daily meal comprising fresh avocado or an isocaloric meal as a control for 12 weeks. The avocado group had substantially greater serum lutein levels and demonstrated improved accuracy in the Flanker task (measure of attentional inhibition). However, there was no significant association between cognitive enhancement and serum lutein levels, while there was also no difference in macular pigment optical density. The structures of the most vital carotenoid compounds present in avocado are illustrated in Figure 3.