Comparative Analysis of Physicochemical Properties and Bioactive Compounds in Two Hilly Region Pineapple Varieties (Ananas comosus L.) for Value-Added Food Applications

Bromelain is a crude protein extract rich in proteolytic enzymes, derived from various parts of the pineapple (Ananas comosus), a member of the Bromeliaceae family. It has numerous uses in biotechnology and medicine, such as meat tenderization, digestive aid, and anti-inflammatory properties. This study aimed to extract, estimate, and partially purify bromelain from two pineapple varieties collected from hilly regions of Bangladesh (Rangamati and Bandarban), and to evaluate their physio-chemical and biochemical characteristics alongside the proteolytic activity of bromelain derived from pulp and peel. Two local pineapple types, Honey Queen (HQ) and Giant Kew (GK), were gathered. Pulp and peel were homogenized in 0.1M phosphate buffer (pH 7.0), filtered, and centrifuged to create crude bromelain extract. Lowry's technique was used to determine the protein concentration. Titrimetric (Gelatin Digestion Unit, GDU) and spectrophotometric (azo-casein hydrolysis) techniques were used to measure proteolytic activity. The optimal temperature and pH were determined. Precipitation with ammonium sulphate was used to partially purify the extract. The fruits' biochemical and physicochemical characteristics were also examined. The highest GDU-based proteolytic activity was found in GK pulp, while azo-casein hydrolysis showed highest activity in GK peel and the lowest in GK pulp. Bromelain was enzymatically active within a pH range of 5.0–8.0 and a temperature range of 35.5–70°C. The ammonium sulfate precipitation method successfully concentrated the enzyme without significant loss of activity. Physico-chemical evaluation revealed that HQ had superior nutritional and biochemical properties compared to GK. According to the study, pineapples grown in mountainous areas show potential as a source of bromelain. The enzyme maintains its functional stability across a broad pH and temperature range owing to the efficient extraction and partial purification procedure, making it appropriate for several industrial and medicinal applications.