Extraction of Crude Bromelain from Pineapple (<em>Ananas comosus</em> L.) Fruit Waste and it&rsquo;s <em>in vitro</em> Protein Digestibility

Abstract

Purpose: Crude bromelain is abundant in pineapple fruit waste and is possible to use in shrimp farming. The objectives of this present study were to investigate extraction conditions and to evaluate in vitro protein digestibility of the shrimp feed supplemented with the crude bromelain extract.Research Method: Crude bromelain was extracted from pineapple fruit waste with either distilled water or tap water and the pH was adjusted, ranging from 5 to 9. The different ripeness stages and weight ratios of waste to water were further investigated. The highest proteolytic and specific proteolytic activities of the extract were selected for suitable extraction conditions. The in vitro protein digestibility of soybean meal and shrimp feed pretreated with crude bromelain extract was evaluated to determine their feasibility to use in shrimp farming.Findings: The crude bromelain derived from the pH 7 preboiled tap water extract exhibited the highest values of both proteolytic activities. The weight ratio of fruit waste to water of 1:0.5 and a ripeness stage of more than 50% yellow peel were the conditions suitable to obtain the highest values of both activities. The in vitro protein digestibility of shrimp feed pretreated with crude bromelain was 68.68 ± 2.70 %, which indicated promotion capability for protein digestion in shrimp during shrimp farming.Research Limitations: A suitable crushing tool for pineapple peel was not available. Therefore, the fragments after crushing the peel were not consistent. Originality/Value: The crude bromelain can be extracted with tap water and used to supplement shrimp feed for the promotion of digestibility.