Pilot scale extraction of crude bromelain from pineapple morris and md2 cultivar using hollow fiber nanofiltration membrane

Abstract

Pineapple (Ananas comosus) is rich with nutrients, incredibly juicy and has been linked to many health benefits. Pineapples are not only taken fresh but they have been commercialized in the canning industry. However, in the canning industry only the flesh is utilized and the rest of the pineapple (50 wt %) such as the core, stem, peels and crown are discarded as waste. In the extraction of bromelain which is a vital proteolytic enzyme, the whole pineapple including its peels, core, stem and crown can be utilized. Bromelain is very valuable and different applications require different bromelain purity; therefore, the extraction and purification technique can be designed depending on the purpose of the bromelain. In this study, nanofiltration (NF) membrane process is used to extract bromelain of Morris and MD2 cultivar from the flesh, crown, stem, core and peel of pineapples. The different parts of the pineapple were crushed to extract the juice. The juice was then centrifuged and the supernatant was then passed through a hollow fiber NF. Finally, the retentate from the different pineapple parts which contain high amounts of bromelain were freeze-dried and quantified. Casein digestion unit method was used to determine the bromelain activity. The amount of bromelain activity increased after every process especially after freeze-drying. The bromelain content in retentate was also analysed using high performance liquid chromatography. Findings revealed that retention time peak of the bromelain appeared within 1 min and bromelain content was found to be highest in peel > flesh > stem > core for both pineapple species. The extracted bromelain solution was then freeze dried and maltodextrin was added so as to ensure encapsulation stability. The concentration of the maltodextrin added varied ranging from 2 – 10 % concentration (w/w %). Water was eliminated during freeze-drying, but unfortunately, bromelain powder with lower maltodextrin concentration (2 – 8 %) were found to be sticky compared to the highest concentration at 10 % which showed an amorphous glassy maltodextrin microstructure (i.e., “bromelain powder”). Upon crushing, the maltodextrin microstructure yielded a free-flowing powder with bromelain enzyme activity of 412.42 CDU/mg. As for the microbiological quality of the bromelain powder, it is safe to be consumed because pathogens such as Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella and Eshrerichia coli were absent in the core and flesh bromelain powder. Enterobacteria and other gram-negative bacteria were less than 10 MPN/ml whereas bacteria count and fungi count was 3.9 x 104 CFU/ml and 6.5 x 101 CFU/ml for core bromelain powder and 5.1 x 104 CFU/ml and 7.1 x 101 CFU/ml for flesh bromelain powder, respectively. 2,2′-diphenyl-1-picrylhydrazyl test results showed the presence of anti-oxidant activity of bromelain was 8.75 % and 11.23 %, respectively for core and flesh pineapple. Meanwhile the anti-inflammatory activity was also detected in the extracted bromelain from the core (50 %) and flesh (45 %) of pineapple. Profitability analysis of the crude bromelain powder plant estimates the rate of return is 34 % and the payback period for the company to start earning profit is 2.92 years. In terms of price, the lowest price in the market for 30 tablets in a bottle was RM 39.14. While the product from this process can be sold at the price of RM 35 for 30 capsules in a bottle, which is cheaper.