Impact of food structure on the compatibility of heated WPI-pectin-complexes in meat dispersions.

Process-stable complexes composed of whey protein isolate (WPI) and sugar beet pectin have great potential as structuring agents or fat replacers in foods. The current study investigates the compatibility of heated WPI : pectin complexes in different meat matrices. Spreadable raw-fermented sausages and sliceable emulsion-type sausages were therefore manufactured containing biopolymer complexes with various WPI : pectin ratios r (2 : 1, 8 : 1). Macro- and microstructural properties of the meat dispersions were analyzed in terms of colour, texture, rheometry, sensory, and confocal laser scanning microscopy (CLSM) measurements. Textural and sensorial results demonstrated that the meat products became increasingly soft and yellowish as the biopolymer ratio r was increased regardless of the meat matrix, whereas pH and water activity values were not affected. CLSM images revealed that the meat protein network became disrupted and loose in the presence of pectin, which was attributed to a thermodynamic incompatibility effect. The results obtained from this study highlight that biopolymer complexes might be suitable fat mimetics, particularly for spreadable meat products.

Mixing behaviour of WPI-pectin-complexes in meat dispersions: impact of biopolymer ratios.

Particulated complexes composed of oppositely charged biopolymers were incorporated into highly concentrated protein matrices as potential fat replacers and structuring agents. A multistep procedure was therefore utilized to generate process-stable complexes, which were subsequently embedded into emulsion-type sausages, whereas macro- and microstructural properties were then assessed. Firstly, stock WPI and sugar beet pectin solutions were mixed under neutral conditions (pH 7) at various biopolymer ratios r (2 : 1, 5 : 1, 8 : 1). Secondly, the pH of the biopolymer mixture was decreased to 3.5 to promote associative complexation. Thirdly, electrostatically attracted biopolymer particles were subjected to a heat treatment (ϑ = 85 °C, 20 min) to enhance their stability against superimposed stresses. Finally, fat-reduced emulsion-type sausages were fabricated containing stable WPI-pectin complexes. The results revealed that the heat treatment increased the pH-stability of the biopolymer complexes. In addition, textural and sensorial analysis demonstrated that the meat products became increasingly soft as the biopolymer ratio r increased. This effect was attributed to thermodynamic incompatibility between meat proteins and beet pectin. The results obtained from this study might have important implications for the fabrication of processed meat products with reduced fat levels.