Control of Alicyclobacillus acidoterrestris in apple juice by pomegranate peel extracts

Alicyclobacillus acidoterrestris has recently obtained great attention in fruit juice industry due to its high resistance to juice pasteurization. Several methods for inhibition of this bacterium have been proposed. Pomegranate peel، as a byproduct of fruit juice factories، has antibacterial and functional properties. Pomegranate peel extracts containing effective compounds were extracted by methanol (MeOH)، ethanol (EtOH) and acetone. In comparison within different extracts، pomegranate peel extracted by acetone (PPEA) had the highest content of phenolic، flavonoid and flavonol contents، (i. e. 226، 70 and 61 mg/g، respectively). Furthermore، 250μg/ml PPEA showed strong anti-Alicyclobacillus acidoterrestris property on orange serum agar and apple juice without any side effects on apple juice turbidity. The extracts obtained by EtOH and acetone during 24 days showed side effects on apple juice turbidity in 1000 μg/ml but the extracts obtained by MeOH did not affect apple juice turbidity at the same time.