Physico-chemical and consumer preference analysis of novel herbal soap enriched with aloe vera (aloe barbadensis)

Abstract

Herbal soaps are popular products at a homemade scale worldwide, but innovative and commercialized local formulations are rare. Sri Lanka has a rich herbal diversity, and several plant extracts have been scientifically proven to show bioactivities such as anti-inflammatory, antibacterial, and antifungal properties. An instance of this is a herbal soap formulation that is useful for treating microbiological infections and regular use. The current study aimed to develop a novel herbal soap enriched with extracts of aloe vera (Aloe barbadensis), citronella oil (Cymbopogon nardus) and black tea (Camellia sinensis), evaluate the physico-chemical properties, and gauging consumer preference for the finished prototype while advancing the technology of the current saponification process. The soap base was produced by saponifying coconut oil with NaOH at 40°C, subsequently value added by incorporating 8% aloe vera gel, 4% citronella oil, and 4% black tea extract, and allowed to age for 72 hours at 32°C. The physico chemical properties were determined as follows: density was 0.95 mg/ml, NaOH ratio was 4.16, free alkali content was 0.028% (0.007 mol/dm³), and Total Fatty Matter (TFM) was 79.6%. These metrics comply with the SLS 34:2009 standards and align with previous research findings, thereby classifying the product as Grade 1. Consumer assessment considered colour, aroma, texture, washing quality, and overall acceptability, revealing a brownish-golden hue, pleasant fragrance, a soft, consistent texture and gentle hand impact. Consumer preference was assessed across diverse socio-economic groups, revealing a high overall acceptability rating of 8.65 out of 10. The study advances soap technology, emphasizing compatibility with existing standards and consumer satisfaction.