Enhancing the Cleaning Efficiency and Fragrance of Recycled Used Cooking Oil-Based Soap with Citrus Fruits

Abstract

This study aimed to find out the effects of combined recycled UCO and citrus essential oil on the cleaning efficiency, foaming capacity, and scent of bar soap. Three formulations were made with different percentages of UCO and essential oil (1:1, 1:2, and 1:3) and were tested for pH, cleansing, foam and fragrance retention. The pH results showed that the 1:1 formulation produced the most appropriate soap, with a pH almost as low as commercial products and with a good texture stability. On the other hand, 1:2 formulation resulted in too much alkalinity, and the 1:3 ratio produced a softer and less stable bar. The performance tests indicated that the UCO based soap made with optimum conditions was a better cleaner than the commercial soap, since it was able to remove more oil in the 6-second and 8-second tests. Besides, the UCO soap together with the commercial soap did not perform similarly in terms of long-term foaming ability, as the UCO soap was able to maintain the height of its foam throughout the 17-minute observation period even though it started off at a lower height. The fragrance test showed that the UCO soap was able to keep the scent much longer, especially when the citrus oil volume was high, thus producing a more potent and longer-lasting aroma compared to the commercial variant. In conclusion, the results affirm the practical applicability of UCO infused with citrus essential oil as an eco-friendly and high-performing substitute to chemically manufactured soaps. The research indicates that the right formulation can turn recycled domestic waste materials into efficient hygiene products that promote environmental sustainability and lessen household waste.

Introduction

Improper disposal of used cooking oil (UCO) causes environmental pollution, sewage blockages, and health hazards, particularly in the Philippines. Recycling UCO into biodegradable soap offers a sustainable solution, reducing waste and supporting circular economy practices. However, traditional UCO soaps often have issues with texture, lather, stability, and fragrance.

Study Aim:
The research aimed to develop an enhanced UCO-based soap using citrus peel extract, improving soap quality, fragrance, cleaning efficiency, and supporting sustainable waste management.

Methodology:

• Materials: UCO, citrus peels, NaOH, distilled water, stearic acid.

• Procedure: Extract citrus oil from peels, mix with UCO in ratios 1:1, 1:2, 1:3, saponify with NaOH, mold, cure, and test for pH, cleaning efficiency, foaming, and fragrance.

• Testing: Comparative tests against commercial soap using descriptive methods.

Results:

• Optimal Ratio: 1:1 UCO to citrus oil provided stable texture and pH within commercial range.

• Cleaning Efficiency: UCO soap removed more oil than commercial soap in all trials.

• Foaming Ability: Better foam retention over time compared to commercial soap.

• Fragrance Retention: Stronger scent, especially at higher citrus oil concentrations.

References

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Copyright

Copyright © 2025 R-lyn C. Cepillo, John Carl Collado, Lance Rovic A. Como, John Mattheson S. Del Pilar, Jerry Dela Cruz, Lalaine B. Desaliza, Trisha Nicole D. Pilar, Trisha Nicole D. Yamo . This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.