Enhancing Bromelain Recovery from Pineapple By-Products: A Sustainable Approach for Value Addition and Waste Reduction

Abstract

Pineapple by-products are good sources of bromelain, a complex enzyme with commercial applications. This study evaluated the feasibility of producing bromelain powders from pineapple waste using an organic solvent-free approach. Pineapple by-products (from var. MD2), including cores, peels, crowns, stems, and basal stems, were homogenized with deionized water, and the pH of the mixture was adjusted to 4.5 and 9 (isoelectric points of fruit bromelain and stem bromelain), clarified, ultra-filtered, and freeze-dried to produce bromelain powders. The enzymatic activity of the bromelain powders was measured using the gelatin and casein digestion methods. The bromelain powders from the crowns did not show significant enzymatic activity (p < 0.05). Meanwhile, bromelain powders produced from the cores and peels had an enzymatic activity of 694 gelatin digesting units (GDU)/g and 124 casein digesting units (CDU)/mg, and 1179 GDU/g and 217 CDU/mg, respectively. Bromelain powders from the basal stems showed the highest enzymatic activity (2909 GDU/g and 717 CDU/mg). Increasing the pH of the liquid mixture before the purification and freeze drying significantly (p < 0.05) reduced the enzymatic activity of the bromelain powders. Using a practical and organic solvent-free approach, this study demonstrates the feasibility of producing bromelain powders with high enzymatic activity from pineapple waste.

Keywords: bromelain; dialysis; enzymatic activity; pineapple by-products; upcycling.

Figure A1

General overview of the gelatin digestion method to determine enzymatic activity of bromelain powders.

Figure A2

General overview of the casein digestion method to determine enzymatic activity of bromelain powders.

Figure 1

Overview of producing freeze-dried (FD) bromelain powders from pineapple cores, peels, and crowns.

Figure 2

Production of freeze-dried (FD) bromelain powders from pineapple cores and peels.

Figure 3

Production of freeze-dried (FD) bromelain powders from pineapple crowns.

Figure 4

Production of freeze-dried (FD) bromelain powders from pineapple cores and peels without pH adjustment.

Figure 5

Production of freeze-dried (FD) bromelain powders from pineapple stems and basal stems.

Figure 6

Crude protein (%, wet basis) of samples obtained during the bromelain extraction from pineapple by-products. ^a–d Means with different letters are significantly different (p < 0.05).