## 5 Stabilization of Bioactive Compounds Extracts  
### Encapsulation Technologies  
Encapsulation is a technology for coating solids, liquids, or gaseous materials into miniature sealed capsules. The capsules can range from nano (10-1000 nm) and micro (1-1000 um) to millicapsules (larger than 1 mm) [92]. The use of microencapsulation technologies aids in the control and release of organoleptic properties as well as ingredients in foods as well as other matrices [93]. Moreover, the composition and activity of bioactive phenolic compounds are stabilized through microencapsulation [94]. There are various techniques employed to create the bioactive-containing capsules. Among these, spray drying is well-known for its simplicity; a solution containing the core and wall material is fed, and then atomized into a mist inside a chamber, to which hot air is then applied to produce a powder. Moreover, scale-up is relatively easy and affordable [95]. Another widely employed encapsulation technology for bioactive-rich extracts is freeze-drying. This is a dehydration process in which sensitive substances are not exposed to high temperatures [96]. The retention of volatile compounds will depend on the chemical nature of the system [97]. Phytochemicals from avocado seeds and peels have been previously microencapsulated through spray-drying, lyophilization, and several chemical coacervation methods [17]. The encapsulation of avocado skin oil has been previously achieved through spray-drying techniques using maltodextrin and Hi-Cap as coating materials, obtaining an encapsulation efficiency in the range of 60 to 80%. In addition, the moisture content, bulk density and mean diameter of the particles were measured, with results ranging from 1.10 to 1.34%, 0.35 to 037 g/cm\({}^{3}\) and 15.10 to 18.22 um, respectively [98]. Additionally, [PERSON] et al. achieved single-core, smooth microcapsules that maintained both antioxidant and antimicrobial activity of the avocado by-product extracts over time through gum Arabic spray-drying. The microcapsule's antioxidant activity only decreased by 2.36% after 4 weeks of storage and maintained antimicrobial activity against _E. coli_ and _S. aureus_ after 7 days, while the unencapsulated extract's antioxidant activity decreased by 7.53% and lost the antimicrobial activity after seven days. The highest yield was found at a 5:10 ratio of extract:gum Arabic, at 49.78% [99]. In the case of freeze-drying, avocado seed extract microcapsules were able to retain the bioactivity after 30 days of storage using cassava and corn starch as wall materials. Cassava starch was found to be more efficient in microencapsulating the extract, and in DPPH and hydroxyl free radical scavenging activity, there was a significant decrease over time; nevertheless, TPC values significantly increased over time. The microcapsules were shelf stable, with the moisture content increasing from 3.0 to 5.4% after 30 days of storage [18]. This demonstrates the potential development of supplements and functional foods. The stabilization of avocado seed and peel extract is of great importance to the food industry where various products could benefit from the antioxidant properties of these compounds. Moreover, the valorization of these agro-industrial residues represents a significant advantage for the avocado oil industry as well as cosmetics and pharmaceutics. For instance, avocado peel extract microcapsules prepared through complex coacervation were effective at reducing oxidation in proteins and reducing the growth of microorganismsin ground beef when incorporated as a preservative. Two wall material matrices were studied, alginate-collagen and pectin-collagen, both emulsified and non-emulsified. These microcapsules showed great results on encapsulation yield, moisture and water activity: 58.72-73.60%, 2.46-6.30% and 0.210-0.342, respectively. Phenolic compounds, such as chlorogenic acid and catechin, were present in the extract, and were not degraded by the acidic pH required for the coacervation process [100].