In‐process flow behavior and structure formation during supercritical fluid extrusion of milk protein concentrate. Issue 4 (13th February 2021)

• Record Type: Journal Article
• Authors: Arora, Bindvi; Schulz, Patrick; Rizvi, Syed S. H.
• Is Part Of: Journal of food processing and preservation. Volume 45:Issue 4(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-02-13
• Subjects: Food -- Preservation -- Periodicals; Food industry and trade -- Periodicals; 664.005
• DOI: 10.1111/jfpp.15348
• Languages: English
• ISSNs: 0145-8892

Abstract

Abstract: The in‐line flow behavior of milk protein concentrate (MPC) and MPC‐sucrose (MPC‐S) blends with and without added supercritical CO2 (SC‐CO2 ) during extrusion was quantified using a slit die rheometer and related to the expansion characteristics of extrudates. The apparent viscosity of the melt was in order: MPC > MPC + SC‐CO2 > MPC‐S > MPC‐S + SC‐CO2 . A lower viscosity reduction factor due to SC‐CO2 incorporation was observed for MPC‐S (1.3–1.1) compared to MPC (1.5–1.2) owing to decreased volume fraction of protein in MPC‐S. Increase in the apparent viscosity increased the expansion ratio for both MPC and MPC‐S extrudates from 2.2 to 4.3 and 1.9 to 4 and decreased the average cell size from 924 to 392 and 936 to 354 µm, respectively. Thus, expansion and cellular architecture of MPC‐based extrudates can be improved by controlling the melt viscosity. The findings of this study could have significant utility in designing novel milk protein‐based products. Practical applications: Milk protein concentrates are highly valuable and nutritionally attractive products and their conversion into expanded and texturally designed foods will be a valuable addition to the market. The cellular architecture of such foods is one of the primary indicators of the consumer‐acceptable quality and depends upon the melt rheology, which in turn is related to the feed composition and processing conditions within the extruder. Relating the in‐line rheological properties to extrudate characteristics can provide better decision‐making ability for the selection of feed ingredients, diluents, and inert ingredients for the development of expanded milk protein puffs of commercial utility.