Pomegranate (Punica granatum) Peels Powder as a Promising Application in Green Technology

Abstract

Peels with rinds of Wonderful cultivar pomegranate were used. Pomegranate wastes (PW) globally represent 1.62 million tons. Such wastes have a detrimental effect to the environment and contribute to methane emissions. An application of green technology to minimize processing wastes was suggested. Hot air and vacuum drying of PW resulted in pomegranate peel powder (PPP). The hot air dried and vacuum dried of PPP contained pectin (10.9 & 14.9 %) , total phenols (125 & 151.7) as gallic acid equivalent /g, neutral detergent fiber (15.8 & 12.3), acid detergent fiber (9.1 &6.6), lignin (2.4 &1.6), cellulose (6.7 & 5.0), and hemi-cellulose( 6.8 & 5.7%), respectively. The PPP was found to be rich in potassium, sodium, calcium and phosphorus, in addition to iron, zinc, and manganese. Three methods for extraction pectin and total polyphenols from PPP were investigated. The three extraction methods are hydrochloric acid extraction, hydrothermal extraction, and a novel method of probe sonication with cellulase. The extraction of pectin ranged between 4.5 to 11.0 %, and total phenols 51.4 to 108.6 mg gallic acid equivalent/g. Hydrochloric acid extraction showed the highest pectin and total phenols yield. The yield from the three extraction methods is low and the three methods are energy and time consuming, and are sources of corrosive chemicals. In conclusion drying PW is considered a beneficial green technology for extending the shelf-life of PW. The dehydration resulted in PPP rich in many bioactive components and minerals with acceptable colour.