Evaluation of phenolics and acrylamide and their bioavailability in high hydrostatic pressure treated and fried table olives

Acrylamide was not detected after high hydrostatic pressure (HHP) of four different table olive varieties (Azeitera, Carrasqueña, Conserva de Elvas, and Morisca). Hydroxytyrosol, tyrosol, oleuropein, procyanidin B1, catechin, vanillic acid, caffeic acid, syringic acid, epicatechin, p-coumaric acid, and verbascoside were the most important phenols found in fresh olives and after HHP treatment. The content of these phenolics decreased from the fresh sample to the oral sample; however, they increased during the in vitro digestion process reaching values that were similar to the fresh samples after the final digestion phase. The highest content of phenolics was found in Carrasqueña variety subjected to intestinal digestion. With HHP, the table olives could be pasteurized without loss of phenolic compound; also the formation of acrylamide was prevented. The frying process of the filled olives induced the formation of acrylamide range from 100 to 250 µg/kg. However, Carrasqueña, the variety with the highest content of phenolic compounds presented the lowest content in acrylamide. Practical applications: High hydrostatic pressure is a nonthermal technology which was applied to pasteurize table olives and to extend their shelf life, preserving the amount of phenolic compounds and preventing acrylamide formation. The frying treatments after HHP contributed to phenols reduction and acrylamide formation. However, the olives with the highest content of natural phenols showed the lower formation of acrylamide.