Effects of extrusion conditions and nitrogen injection on physical, mechanical, and microstructural properties of red lentil puffed snacks

Luo S., Chan E., MASATCIOĞLU M. T., Erkinbaev C., Paliwal J., Koksel F.

Food and Bioproducts Processing, vol.121, pp.143-153, 2020 (SCI-Expanded, Scopus) identifier identifier

  • Publication Type: Article / Article
  • Volume: 121
  • Publication Date: 2020
  • Doi Number: 10.1016/j.fbp.2020.02.002
  • Journal Name: Food and Bioproducts Processing
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Biotechnology Research Abstracts, CAB Abstracts, Communication Abstracts, Compendex, Food Science & Technology Abstracts, INSPEC, Metadex, Veterinary Science Database, Civil Engineering Abstracts
  • Page Numbers: pp.143-153
  • Keywords: Colour, Extrusion, Microstructure, Nitrogen injection, Red lentil, Texture
  • Hatay Mustafa Kemal University Affiliated: Yes

Abstract

Purpose: Red lentils are rich in proteins and fibres, and thus have great potential to be used as healthy ingredients in extruded snacks. However, at high protein and fibre concentrations, the level of expansion, microstructure uniformity and textural appeal are impaired. Using physical blowing agents during extrusion can overcome these quality issues. This study investigates the effects of moisture content (18%–22%), screw speed (150 rpm–200 rpm), and blowing agent (i.e., N2) injection pressure (0−500 kPa) on physical, mechanical and microstructural properties of puffed red lentil snacks. Principle results: Compared to conventional extrusion, N2 injection at 300 kPa decreased extrudate density from 0.25 to 0.41 kg/m3 to 0.12 to 0.26 kg/m3 (across all feed moistures and screw speeds studied), and substantially altered the extrudate's microstructure. Extrudates with N2 injection had numerous small cells that were more evenly distributed. Moreover, an increase in feed moisture from 18% to 22% increased extrudate hardness and decreased crispiness. Major conclusions: N2 injection during extrusion has a great potential in manipulating extrudate expansion, microstructure, texture, and colour of red lentil extrudates. Extrudates produced with 300 kPa N2 injection pressure had the maximum expansion compared to other N2 injection pressures studied.