food and bioproducts processing 9 1 ( 2 0 1 3 ) 183–191 Contents lists available at SciVerse ScienceDirect Food and Bioproducts Processing j ourna l ho me page: www.elsevier.com/locate/fbp Effect of flaxseed processing on engineering properties and fatty acids profiles of pasta Sébastien Villeneuve * , Louis-Philippe Des Marchais, Vanessa Gauvreau, Samuel Mercier, Chi Bao Do, Yves Arcand Agriculture and Agri-Food Canada, Food Research and Development Centre, 3600 Casavant Blvd West, Saint-Hyacinthe, Quebec, Canada J2S 8E3 a b s t r a c t Flaxseed contains numerous bioactive compounds which induce various biological effects. Among bioactive com- pounds, flaxseed contains 38–45% oil, of which up to 59% is -linolenic acid. Focus has recently been put on the technical difficulties of processing flaxseed pasta and studies have shown that flaxseed could tolerate some processing conditions. A close link between pasta processing conditions and the in vitro digestion of the food matrix has also been identified. The aim of this study were (1) to understand the impact of flaxseed processing and content on engineering properties of pasta after the extrusion, the drying and the cooking process; (2) to characterize the fatty acids profile of flaxseed-enriched pasta during the processing and after the in vitro digestion. Two processes were considered prior to the incorporation of flaxseed into pasta at levels of 15% and 30% (dry basis): (Process A) conditioning and milling of flaxseed; (Process B) conditioning of flaxseed, oil pressing, milling of flaxseed cake and reformulation. Results showed that pressing oil from flaxseed and then milling the flaxseed cake (Process B) allowed obtaining an average particle size smaller than milling the whole flaxseed (Process A) which doubled the flaxseed- to-semolina particles ratio. Flaxseed processing, prior to the incorporation into pasta, and content had impacts on engineering properties after the extrusion, the drying and the cooking process and, affected the protection and the release of free fatty acids during in vitro digestion. While free fatty acids profiles remained relatively stable through all steps of pasta processing, they were affected by the in vitro digestion. Decrease in the proportion of omega-3 fatty acid (C18:3) was more important for the Process A compared to the Process B. Crown Copyright © 2012 Published by Elsevier B.V. on behalf of The Institution of Chemical Engineers. All rights reserved. Keywords: Flaxseed pasta; Conditioning; Milling; Cooking; Engineering properties; In vitro digestion; Free fatty acids 1. Introduction There is a new key driver in the food industry: consumers want foods that provide beneficial effects for their health. As a result, several scientists focus on the identification, extrac- tion, concentration and/or the isolation of bioactives in order to make them available for the industry in the form of new “health and wellness” ingredients. This trend will continue to grow in the future. In this context, there is a need to utilize some strategies/technologies to incorporate bioactive ingre- dients into food matrices and to ensure their stability until they reach their action sites (e.g. digestive system and target ∗ Corresponding author. Tel.: +1 450 768 3335; fax: +1 450 773 8461. E-mail address: sebastien.villeneuve@agr.gc.ca (S. Villeneuve). Received 7 June 2012; Received in revised form 30 August 2012; Accepted 11 September 2012 tissues). The concept of a food matrix points to the fact that bioactives are contained into a larger network that may be of natural origin or the result of a microstructure produced by processing, where they may interact at different degrees with the components and structures of the network (Parada and Aguilera, 2007). For bioactives, the stability can be measured, first, by its bioaccessibility (fraction that is released from the food matrix and is available for intestinal absorption), then, by its bioavailability (fraction of ingested bioactive that is avail- able for utilization in normal physiological functions and for storage) and bioactivity at target tissues. Bioactives are thus considered “unstable” if, at the end of matrix digestion, they are not bioavailable or active due to insufficient or excessive protection. 0960-3085/$ – see front matter Crown Copyright © 2012 Published by Elsevier B.V. on behalf of The Institution of Chemical Engineers. All rights reserved. http://dx.doi.org/10.1016/j.fbp.2012.09.002