Encapsulation of Bioactive Compounds with Milk, Maltodextrin and Gum Acacia Improve Its Stability

This study was carried out for extraction of polyphenols from banana peels and entrapment of the polyphenols so obtained into whole milk via encapsulation techniques. Three different solvent (ethanol, methanol and acetonitrile) were used for the extraction of polyphenols using three stage of extraction. The extracted polyphenols was encapsulated into 200 ml of whole milk by spray drying using different concentrations of gum acacia (4, 6 and 8% w/v) and 10% w/v maltodextrin DE18. The ratio between cores to coating materials was 1:10. Though acetonitrile extracted higher amount of polyphenol, ethanol was selected for subsequent studies of extraction of polyphenol, as per the legislations regarding use of Food-grade solvents. Total phenolic content of ripe banana peel extract was 143 mg GAE/100g dry extract, total flavonoid content was 156.139 mg rutin/100g dry extract and 80.41% DPPH activity at a concentration of 12 mg/ml. There was no significant difference among all three samples 4% gum acacia+10% maltodextrin (A), 6% gum acacia+10% maltodextrin (B) and 8% gum acacia+10% maltodextrin (C) in terms of moisture content and hygroscopicity. However, insolubility index showed that sample A possessed a higher solubility index. Encapsulation techniques suggested that sample A showed higher encapsulation efficiency than others. Statistical analysis suggested that there was no significant difference among samples A, B and C during storage at 4 o C for the time period (30 days) studied, in terms of polyphenol retention rate. However, samples stored at 25 and 37 o C showed significant difference in the retention rate. Among all the three samples, sample B showed significantly lower polyphenol degradation rate of 4.01, 4.87 and 5.70×10-3 /day at 4, 25 and 37 o C, respectively. Results indicate that extracted polyphenols can be encapsulated using a combination of gum acacia either 4 or 6% w/v and 10% maltodextrin along with milk proteins at 4 o C for longer shelf life.