Preparation of pomegranate peel extract powder and evaluation of its effect on functional properties and shelf life of curd

A study was conducted to prepare pomegranate peel extract (PPE) powder and evaluation of its effect on functional properties and storage stability of curd. The extraction was carried out with ethanol and water and the extracted samples were analysed for anti-oxidant activity and total phenolic content (TPC). Ethanol based extract had significantly (p < 0.05) higher anti-oxidant activity and TPC as compared to aqueous extract. Hence, ethanol based extract was selected for powder preparation. It was mixed with drying aids viz. whey protein concetrate-70 (WPC-70) and skimmed milk powder (SMP) to avoid stickiness during drying. The WPC-70 based PPE powder showed higher anti-oxidant activity and TPC than SMP based PPE. Both PPE powders were incorporated into curd at different concentrations (0.5, 1 & 1.5%). Anti-oxidant activity and TPC of curd increased with increase in PPE concentration, however, sensorial attributes decreased at higher PPE concentration. Curd with 1% PPE powder showed considerable anti-oxidant activity and acceptable sensory attributes. During storage, PPE added curd shown resistance to increase in microbial count, change in acidity and whey syneresis. The shelf life of the PPE added curd was increased by 6 days as compared to control sample at 5 °C.