Hybrid Sausages: Modelling the Effect of Partial Meat Replacement with Broccoli, Upcycled Brewer's Spent Grain and Insect Flours

Abstract

The social, environmental and health concerns associated with the massive consumption of meat products has resulted in calls for a reduction in meat consumption. A simplex lattice design was used for studying the effect of combining broccoli, upcycled brewer’s spent grain (BSG) and insect flours from Tenebrio molitor (IF) as alternative sources of protein and micronutrients, in hybrid sausages formulation. The techno-functional properties of the ingredients and the nutritional and textural properties of nine hybrid sausages were analysed. The effect of adding these ingredients (constituting 35% of a turkey-based sausage) on protein, fat, fibre, iron and zinc content, and textural properties (Texture Profile Analysis (TPA) and Warner−Bratzler parameters) were modelled employing linear regression (0.72 < R2 < 1). The “desirability” function was used for multi-response optimisation of the samples for the highest protein content, optimum chewiness and a* value (closeness to red). The analysis of sensory data for the three optimised samples showed no significant differences in juiciness and odour between the hybrid meat sausage with 22% broccoli, 3% BSG, and 10% IF and the commercial Bratwurst sausage elaborated exclusively with animal protein. Colour, appearance, chewiness and pastiness were rated higher than for the reference. The instrumental chewiness highly correlated with sensorial chewiness (R2 = 0.98). Thus, a strategy introducing less refined and more sustainable sources of protein and micronutrients was successfully employed to model and statistically optimise a meat product formulation with reduced animal protein content.

Keywords: brewer’s spent grain; hybrid meat; insects; statistical optimisation; sustainable nutrition; upcycling.

Figure 1

Simplex design plot of ingredient proportions for sausages with replacements adding up to 35%. The samples, labelled from F1 to F9, contain different percentages of broccoli, upcycled brewer’s spent grain and insect flour (BR, BSG, IF): F1 (35, 0, 0), F2 (30, 5, 0), F3 (25, 0, 1), F4 (20, 5, 10), F5 (30, 0, 5), F6 (32, 3, 0), F7 (25, 5, 5), F8 (22, 3, 10) and F9 (27, 3, 5).

Figure 2

Images of the 9 hybrid sausages used in the experiments. The samples, labelled from F1 to F9, contain different percentages of broccoli, upcycled brewer’s spent grain and insect flour (BR, BSG, IF): F1 (35, 0, 0), F2 (30, 5, 0), F3 (25, 0, 1), F4 (20, 5, 10), F5 (30, 0, 5), F6 (32, 3, 0), F7 (25, 5, 5), F8 (22, 3, 10) and F9 (27, 3, 5).

Figure 3

Texture Profile Analyses (TPA) of the 9 hybrid sausages used in the experiments. The samples, labelled from F1 to F9, contain different percentages of broccoli, upcycled brewer’s spent grain and insect flour (BR, BSG, IF): F1 (35, 0, 0), F2 (30, 5, 0), F3 (25, 0, 10), F4 (20, 5, 10), F5 (30, 0, 5), F6 (32, 3, 0), F7 (25, 5, 5), F8 (22, 3, 10) and F9 (27, 3, 5). Different letters in the same bar are significantly different according to Tukey’s test (p < 0.05).

Figure 4

Warner–Bratzler analyses of the 9 hybrid meat samples. The samples, labelled from F1 to F9, contain different percentages of broccoli, upcycled brewer’s spent grain and insect flour (BR, BSG, IF): F1 (35, 0, 0), F2 (30, 5, 0), F3 (25, 0, 1), F4 (20, 5, 10), F5 (30, 0, 5), F6 (32, 3, 0), F7 (25, 5, 5), F8 (22, 3, 10) and F9 (27, 3, 5). Different letters in the same bar are significantly different according to Tukey’s test (p < 0.05).3.4. Modelling and Optimisation.

Figure 5

Ternary diagrams of the responses where R² > 90%. The diagrams show the content of protein, fat and fibre content (percentage), the springiness, resilience and chewiness and the L*a*b* colour parameters. The samples, labelled from F1 to F9, contain different percentages of broccoli, upcycled brewer’s spent grain and insect flour (BR, BSG, IF): F1 (35, 0, 0), F2 (30, 5, 0), F3 (25, 0, 1), F4 (20, 5, 10), F5 (30, 0, 5), F6 (32, 3, 0), F7 (25, 5, 5), F8 (22, 3, 10) and F9 (27, 3, 5).

Figure 6

Boxplots for the attributes assessed for each sample (F1, F3 and F8) compared to the commercial sample QDA (horizontal red line). Dark grey area represents QDA values ± 1. Red dots represent the average of each panellist; black dots represent the outliers.