Pomegranate (Punica granatum L.) fruit and its processed products (e.g. juice) are known as one of the richest natural sources of antioxidant polyphenolic compounds. The versatile biological activity of pomegranates, including antiatherogenic, antihypertensive, anti-inflammatory and antimicrobial effects, is primarily associated with punicalagins, the ellagitannins abundant in pomegranate peel. Punicalagins are water-soluble and have high bioavailability. However, significant sugar content in pomegranate juice and high astringency of punicalagins limit the direct consumption of pomegranate products. Therefore, a taste-neutral vector to deliver the pomegranate bioactivity without interference with food organoleptic properties is in great demand.
In this work, we have developed a method for preparing a new product from pomegranate processing wastes, such as pomace, juice sediment and retentate. The product comprises solid (powdered) microparticles of size less than 100 µm on their largest dimension, typically 1-3 x 10-20 µm, insoluble in water and organic solvents, having no odor or taste and possessing radical-scavenging capacity of 600-1000 µM Trolox equivalents g-1. The particles are of exclusively fruit origin, comprising natural complex of phenolic compounds, proteins and polysaccharides.
Under simulated gastric fluid conditions the microparticles were shown to undergo hydrolysis with release of free punicalagins and other phenolic compounds. The hydrolysis was associated with the transfer of antioxidant activity from the insoluble fraction of the microparticles to the liquid phase, improving bioavailability of phenolic antioxidants. Adding microparticles to meat or dairy matrices controlled their oxidative deterioration with efficacy comparable to synthetic antioxidants BHA/BHT. The microparticles added to oxidation-prone foods, such as meat products, may help controlling the postprandial formation and absorbance of harmful lipid peroxidation products in gastrointestinal system. Topical application of a cream comprising the pomegranate microparticles prevented lipid oxidation in excised chicken skin subjected to acute heat injury in a manner similar to vitamin E-containing cream. Additional data about the microparticle structure will be presented at the meeting.
Principal investigator: Dr. Victor Rodov vrodov@agri.gov.il
