Date of Publication
11-2025
Document Type
Master's Thesis
Degree Name
Master of Science in Chemical Engineering
Subject Categories
Chemical Engineering
College
Gokongwei College of Engineering
Department/Unit
Chemical Engineering
Thesis Advisor
Lawrence P. Belo
Cynthia F. Madrazo
Defense Panel Chair
Allan N. Soriano
Defense Panel Member
Angelo Earvin S. Choi
Rhoda B. Leron
Abstract (English)
The cacao bean shell (CBS), a by-product of cacao processing, is a promising source of polyphenols. However, conventional extraction methods often rely on volatile solvents or energy-intensive techniques, limiting their scalability and sustainability. This study investigated the use of Surfactant-Assisted Extraction (SAE) using Tween 80 as a green alternative for polyphenol recovery from CBS. The effects of pH (4 – 8), Tween 80 concentration (0.5 – 1.5% w/v), and solid-to-liquid (S/L) ratio (0.02 – 0.08 g/mL) were optimized using Response Surface Methodology (RSM) with a Face-Centered Central Composite Design (FCCCD). The evaluated responses were total polyphenol content (TPC), total flavonoid content (TFC), and antioxidant activity (AOA), with catechin quantified via HPLC as a representative flavonoid to confirm observed trends. All regression models were statistically significant (p < 0.0001) with R² > 0.95, and validation experiments confirmed predictive adequacy within 95% prediction intervals. Individually optimized conditions yielded maximum TPC, TFC, and AOA values of 25.00 ± 0.30 mg GAE/g, 22.30 ± 1.21 mg CE/g, and 50.13 ± 3.55 μmol FeCl₂/g, respectively. Multi-response optimization identified pH 8, 1.24% Tween 80, and 0.03 g/mL as the best compromise, achieving TPC, TFC, and AOA values of 21.89 ± 1.06 mg GAE/g, 20.35 ± 1.98 mg CE/g, and 45.45 ± 0.50 μmol FeCl₂/g, respectively. Extraction efficiency generally improved with increasing pH and Tween 80 concentration, whereas lower S/L ratios favored TPC and TFC. However, AOA peaked at a moderate S/L ratio (0.05 g/mL), suggesting antagonistic interactions among polyphenols. The highest catechin yield obtained was 2.71 ± 0.37 mg/g. Catechin trends aligned with TPC and TFC but not with AOA, highlighting the complexity of polyphenol interactions and the need to evaluate both yield and bioactivity. The polyphenol extraction and antioxidant activity obtained from SAE were within the range reported in literature, supporting the potential of surfactant-assisted extraction as a green technology for the valorization of cacao bean shell.
Abstract Format
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Abstract (Filipino)
Ang balat ng buto ng kakaw o cacao bean shell (CBS) na karaniwang tinatapon mula pagproseso ng kakaw, ay maaaring pagkuhanan ng mga polyphenol. Ang nakagawian na paraan sa pagkuha ng mga polyphenol ay umaasa sa mga organic solvent o mga paraan na nangangailangan ng mataas na enerhiya, kaya't nalilimitahan ang malawakang paggamit nito. Sinuri sa pag-aaral na ito ang paggamit ng Surfactant-Assisted Extraction (SAE) gamit ang Tween 80 bilang alternatibong teknolihiya para sa pagkuha ng polyphenol mula sa CBS. Ang epekto ng pH (4 – 8), konsentrasyon ng Tween 80 (0.5 – 1.5% w/v), at solid-to-liquid (S/L) ratio (0.02 – 0.08 g/mL) sa Total polyphenol content (TPC), Total flavonoid content (TFC), at antioxidant activity (AOA) ay sinuri at in-optimize gamit ang Response Surface Methodology (RSM) na may Face-Centered Central Composite Design (FCCCD). Ang catechin, isa sa mga major flavonoids sa CBS, ay tinukoy gamit ang HPLC upang kumpirmahin ang mga naobserbahang mga trend. Lahat ng regression model ay estadistikang makabuluhan (p < 0.0001) na may R² > 0.95. Sinuportahan din ng mga validation experiments ang predictive adequacy ng modelo na pumaloob sa 95% prediction intervals ang mga predicted values. Nakamit mula sa individual optimization ang pinakamataas na TPC, TFC, at AOA na 25.00 ± 0.30 mg GAE/g, 22.30 ± 1.21 mg CE/g, at 50.13 ± 3.55 μmol FeCl₂/g, ayon sa pagkakabanggit. Natukoy naman sa multi-response optimization ang pH 8, 1.24% Tween 80, at 0.03 g/mL bilang pinakamainam na kompromiso, na nagresulta sa TPC, TFC, at AOA na 21.89 ± 1.06 mg GAE/g, 20.35 ± 1.98 mg CE/g, at 45.45 ± 0.50 μmol FeCl₂/g, ayon sa pagkakabanggit. Sa kabuuan, tumataas ang extraction efficiency sa pagtaas ng pH at konsentrasyon ngTween 80 , samantalang mas pabor ang mababang S/L ratio sa TPC at TFC. Gayunpaman, ang pinakamataas na halaga ng AOA ay naitala sa katamtamang S/L ratio na 0.05 g/mL, na nagpapakita ng antagonistic interaction ng mga polyphenol. Ang pinakamataas na yield ng catechin na nakuha ay 2.71 ± 0.37 mg/g. Ang trend ng catechin ay tumugma sa trend ng TPC at TFC ngunit hindi sa AOA, na naglalarawan ng kompleksidad ng ugnayan ng mga polyphenol at kahalagahan ng mainam na pagaaral sa yield at bio-functional activity. Ang extraction ng polyphenol at antioxidant activity ay naaayon sa isinasaad sa literatura, na nagpapakita sa potensiyal ng surfactant-assisted extraction bilang alternatibong teknolohiya para sa pagtaas ng halaga ng CBS.
Abstract Format
html
Language
English
Format
Electronic
Keywords
Polyphenols
Recommended Citation
Chua, J. C. (2025). Optimization of surfactant-assisted extraction of polyphenols from cacao bean shell. Retrieved from https://animorepository.dlsu.edu.ph/etdm_chemeng/33
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Embargo Period
11-2026
