Pectin Isolation from Interdonato Lemon (<i>Citrus-limon</i>) Using Various Solvents and Its Application in Pineapple Jelly

Interdonato lemon (Citrus limon) is a rich source of pectin. However, commercial extraction and application in jam and jelly have not been performed yet. The study's objective was to use ethanol and acetone precipitation to extract pectin from Interdonato lemon. Interdonato lemon was taken and passed through preliminary treatment to obtain albedo and dried in a dryer at 65 °C for 12 hr. To extract pectin, the dried albedo was heated in acidic water (pH 1 for both ethanol and acetone extraction maintained with citric acid) at 88 °C for 45 minutes. The resulting slurry was then filtered using muslin cloth, rinsed with hot water (88 °C), and filtered using Whatman No. 41 filter paper. Finally, the filtrate was precipitated using 95% ethanol and acetone in a ratio of 2:1 (sample: solvent), and centrifuged at 4,500 rpm for 20 min. The pectin was scrapped and dried in a hot air oven at 48 to 52 °C for 15 hr (ethanol) and a similar temperature for 18 hr (acetone). Ethanol-extracted pectin was superior in terms of chemical and physical analysis. Statistical analysis showed significant differences (p < 0.05) in all parameters of ethanol and acetone-extracted pectin except anhydrouronic acid (AUA) % and ash content. Moreover, the best pectin was utilized in the preparation of three pineapple jelly samples prepared with different extracted pectin concentrations (0.75%, 1%, and 1.5%) and coded as A, B, and C and compared with pineapple jelly prepared with Analytical Reagent (AR) grade pectin (100 grade) coded with sample D. From the sensory evaluations, sample B showed superior in terms of color, appearance, taste, texture, and overall acceptance. Hence, the findings highlighted actionable recommendations for commercially extracted pectin from the Interdonato lemon fruit albedo portion and applied to different food and pharmaceutical products.