Ultrasound Assisted Extraction of Pectin from Kaffir Lime Peel

Lim, Wei Yin (2023) Ultrasound Assisted Extraction of Pectin from Kaffir Lime Peel. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

Kaffir lime peel is known to contain a significant amount of pectin; however the peel is often discarded as waste in the juice processing. This study aims to assess the potential to utili s e ultrasound assisted extraction technique to extract pectin from kaffir lime peel s . The effects of ultrasound amplitude (25%, 50%, 75%), extraction time (10 min, 25 min, 40 min), and pH (1.5, 2.0, 2.5) on the yield, colo u r, degree of esterification (DE), methoxyl content (MC), equivalent weigh t (EW) and anhydrouronic acid content ( of pectin extracted from kaffir lime peel s were investigated. Box Beh nken design (BBD) via Response surface methodology (RSM) was u tilised to optimi s e the ultrasound assisted extraction parameters. The pectin extracted under the optimal ultrasound assisted extraction conditions were compared with the pectin extracted under conventional extraction method and commercial pectin based on the quality properties. The results showed that the ultrasound amplitude, extraction time, and pH had a significant impact ( p < 0.05) on the pectin yield and equivalent weight. However, only the pH had a significant effect ( p < 0.05) on the L * value. Both the extraction time and pH significantly influenced ( p < 0.05) the anhydrouronic acid content, whereas the ultrasound amplitude and extraction pH had a significant impact ( p < 0.05) on the degre e of esterification. The optimal extraction parameters obtained from Box Behnken design were 70% of ultrasound amplitude, 40 min of extraction time, and 2.5 of extraction pH with the desirability at 0.7141, which resulted in 13.57% of pectin yield, 627.45 g of equivalent weight, 1.22% of methoxyl content, 21.73% of degree of esterification, and colour (38.5 of L *, 2.5 of a *, and 19.7 of b *). The pectin extracted under optimal ultrasound assisted extraction conditions was significantly different ( p < 0.05) from the pectin extracted under conventional extraction method and commercial pectin in terms of L * value and moisture content. This study demonstrates the promising use of kaffir lime peel as a viable pectin source and ultrasound technology shows potential to be used as a viable alternative for extracting pectin from kaffir lime peel. Keywords: Kaffir lime peels; pectin; ultrasound; response surface methodology; optimisation