Optimization of the Microwave-Assisted Extraction Process of Bioactive Compounds from Annatto Seeds (Bixa orellana L.)

Abstract

This study deals with the extraction, optimization, and evaluation of the antioxidant and antimicrobial activities of bioactive compounds obtained from the seeds of annatto using microwave-assisted extraction as compared to leaching. Annatto seeds were subjected to a microwave treatment of 2450 MHz and power of 700 watts using a response surface design involving four factors: pH (4–11), solvent concentration (ethanol) (50–96 %), solvent-to-seed ratio (2–10), and microwave exposure time (0–5 min). The contents of polyphenol compounds and bixin were taken as response variables. Subsequently, the antioxidant and antimicrobial activities were assessed at the optimal processing conditions predicted by the experimental design. Microwaves, solvent concentration, and the solvent-to-seed ratio showed a statistically significant effect for the extraction of polyphenol compounds and bixin. Thus, microwaves accelerated the extraction of those compounds and the slight increase in temperature caused some degradation of the polyphenol compounds. The microwave-assisted extraction increased the contents of polyphenols and bixin along with their antioxidant activity as compared to leaching extraction. However, this technique does not significantly improve the antimicrobial activity against Bacillus cereus and Staphylococcus aureus.

Use of Plant Proteins as Microencapsulating Agents of Bioactive Compounds Extracted from Annatto Seeds (Bixa orellana L.)

“…The previously diluted annatto seed extract (~0.1 g of freeze-dried sample suspended in 30.0 mL of DI water) was again diluted with acetone to obtain an absorbance below 1.0 at 486 nm employing a UV/Vis spectrophotometer (Genesys 10S UV-Vis, Thermo Scientific, Waltham, MA, USA). The mg of bixin per gram of sample was calculated from a calibration curve of bixin standard built between 12.5 mg/L and 0.19 mg/L [37].…”

Antioxidant Activity of Polyphenolic Plant Extracts

“…The results showed that the optimal extraction conditions were pH 7.0, solvent concentration 96% v/v, solvent-to-seed ratio 6:1 and microwave time 5 min [42]. The main polyphenols identified in the B. orellana seed extract were apigenin, hypolaetin, and caffeic acid derivatives [42]. Moreover, the B. orellana seed extract isolated by MAE had higher antioxidant activity and polyphenolic yield than that isolated by leaching [42].…”

“…In addition, isolation of M. communis polyphenolic extract using UAE was more efficient than MAE and conventional solvent extraction methods [41]. In another study, Quiroz et al [42] used MAE to isolate polyphenolic extract from annatto (Bixa orellana L.) seeds. The results showed that the optimal extraction conditions were pH 7.0, solvent concentration 96% v/v, solvent-to-seed ratio 6:1 and microwave time 5 min [42].…”

“…In another study, Quiroz et al [42] used MAE to isolate polyphenolic extract from annatto (Bixa orellana L.) seeds. The results showed that the optimal extraction conditions were pH 7.0, solvent concentration 96% v/v, solvent-to-seed ratio 6:1 and microwave time 5 min [42]. The main polyphenols identified in the B. orellana seed extract were apigenin, hypolaetin, and caffeic acid derivatives [42].…”

“…The main polyphenols identified in the B. orellana seed extract were apigenin, hypolaetin, and caffeic acid derivatives [42]. Moreover, the B. orellana seed extract isolated by MAE had higher antioxidant activity and polyphenolic yield than that isolated by leaching [42]. Another "green extraction method," far IF, was used by Azad et al [43] in order to isolate antioxidant polyphenolic compounds from Angelica gigas Nakai.…”