Storage Stability of Sterilized Liquid Extracts from Pomegranate Peel
Article first published online: 3 JUL 2012
© 2012 Institute of Food Technologists®
Journal of Food Science
Volume 77, Issue 7, pages C765–C772, July 2012
How to Cite
Qu, W., Breksa III, A. P., Pan, Z., Ma, H. and Mchugh, T. H. (2012), Storage Stability of Sterilized Liquid Extracts from Pomegranate Peel. Journal of Food Science, 77: C765–C772. doi: 10.1111/j.1750-3841.2012.02779.x
- Issue published online: 3 JUL 2012
- Article first published online: 3 JUL 2012
- MS 20111455 Submitted 12/6/2011, Accepted 3/29/2012.
- phenolic compounds;
- storage stability
Abstract: Pomegranate marc, a byproduct of commercial juice production, has shown promise as a starting material for the recovery of health promoting phenolic compounds. The stability of aqueous extracts prepared from pomegranate marc was evaluated in preparation to directly using these extracts as nutraceuticals or food additives. The liquid extracts were produced under extraction conditions of 25 °C, water to peel ratio of 50 : 1 (w/w) for 2 min, and then sterilized at 121 °C for 10 s. Storage conditions tested included 3 different pH values (3.5, 5.0, and 7.0) and 2 packaging methods (no light and exposure to light). The extracts were evaluated for industrial (pH, total soluble solid content, and clarity), color, spectral, and antioxidant characteristics over a period of 180 d. The results showed that both pH value and packaging method significantly influenced the industrial and color characteristics of the extracts. The high pH had a negative effect on spectral and antioxidant characteristics. Therefore, the recommended storage conditions are low pH and with dark packaging to maintain the high storage stability. After 180 d of storage, extracts stored at low pH (3.5) in dark packaging still retained 67% and 58% of their total soluble phenolic concentration and antioxidant activity, compared with 61% and 43% for high pH (7.0) samples, and were composed of high concentrations of punicalagins A and B, gallic, and ellagic acids.
Practical Application: The present research developed an effective recovery of phenolic compounds from pomegranate marc to be used as nutraceuticals or food additives. The aqueous extract product has good quality characteristics with high industrial and color stability, and total phenolic content and antioxidant activity, when stored at pH 3.5 in dark packaging for up to 180 d. The evaluation results of storage stability reported here are important for commercialization.