LAUSR

BACKGROUND The partial or total substitution of animal fat by a gelled emulsion elaborated with cocoa bean shell and walnut oil in beef burgers was assessed in terms of bioactive compounds stability (polyphenolic and methylxanthines compounds, and fatty acid profile); bioaccessibility, and colon available indices as well as lipid oxidation after in vitro gastrointestinal digestion (GID). RESULTS After GID of reformulated beef burgers no free polyphenolic compounds were detected in the soluble fraction, while in the bound fraction a reduction, with respect to the undigested sample, from 47.57 to 53.12% for protocatechuic acid; from 60.26 to 78.01% for catechin, and from 38.37 to 60.95% for epicatechin were obtained. The methylxanthines decreased significantly their content after GID. Thus, theobromine content fell between 48.41 and 68.61% while caffeine content was reduced between 96.47 and 97.95%. The fatty acid profile of undigested samples was very similar to that of digested samples being in the control burger oleic acid (453.27 mg g-1 ) and palmitic acid (242.20 mg g-1 ) the predominant fatty acids, whereas in reformulated burgers a high content of linoleic acid (304.58 and 413.35 mg g-1 ) and α-linolenic acid (52.44 and 82.35 mg g-1 ) was found. As expected, both undigested and digested reformulated samples presented a higher degree of oxidation than the control sample. CONCLUSIONS The reformulated beef burgers with cocoa bean shells flour and walnut oil were a good source of bioactive compounds, which showed good stability after in vitro gastrointestinal digestion. This article is protected by copyright. All rights reserved.