Extraction and enzymatic modification of dietary fibre from purple aubergine

Abstract

This research scrutinised the opportunity of upcycling waste from the food industry by extracting dietary fibre from purple aubergine. One of the challenges addressed was enzymatic browning, which negatively influenced the quality of the fibre extracted from fresh aubergine. Various pre-treatment procedures were assessed, including using citric acid, sulphite immersion, peeling and thermal processing, to determine their effects on extraction yield, colour, and the functionality of the resultant dietary fibre. Findings indicated that a pre-treatment method involving aubergine peeling, sulphite solution immersion, and subsequent steaming before extraction produced optimal results, enhancing both whiteness index and water-holding capacity. Experiments were conducted with traditional enzymes supplemented with cellulase, xylanase, and lipase for enzymatic extraction. The addition of lipase notably elevated the extraction yield and water-holding capacity, albeit with an undesired darkening effect on the dietary fibre. In contrast, the application of xylanase emerged as the most effective treatment, delivering the highest overall quality for the derived dietary fibre.

Keywords

• browning reaction
• cellulase
• lipase
• sulphite
• water holding capacity
• xylanase