The application opportunities for proteins from pulses are vast and manifold. Foods based on pulse proteins will help reach sustainability goals and provide nourishment for the growing global population. However, industry experts are calling for market development of pulse protein co-products: starch and fibers. Bühler has recognized the need to explore and gain insight into the value-add applications of pulse starches and fibers. Using our wide-ranging application capabilities, we have launched several experiments to assess the suitability and potential of the yellow pea and faba bean starch-rich fractions.
In this experiment, we evaluated breads baked with varying degrees of flour-substitution with a starch-rich fraction won by the dry fractionation (grinding and air-classification) of yellow peas and faba beans. These starch-rich fractions are comparable to wheat flour in their composition (Table 1) but can assume the same clean label, allergen-free, non-GMO and colorless ingredient benefits as their protein-rich counterparts. To assess their suitability as an additional ingredient, two simple bread recipes (Tables 2 & 3), were evaluated for dough handling, characteristic properties and a hedonic sensorial evaluation. Further, Bühler’s JetMix Hydration Solution was tested to evaluate the potential influence of a technological process optimization on an industrial bakery level.
Evaluation of pulse starch-rich fraction substitution levels
For both types of bread, 10% to 50% starch-rich fraction was substituted for the flour (Tables 2 & 3). The more starch-rich fraction was added, the less water was added to make up for the decreased binding capacity of water of undamaged starch granules. Otherwise, the processing parameters for kneading, resting, and fermentation (Table 4) were kept constant for the respective breads. After fermentation, it was observed that air pockets on the dough surfaces formed on high-substitute doughs. These were likely due to a weaker gluten network.
The baked breads showed several features that correlated positively to an increase in starch-rich fraction substitution: The more starch-rich fraction was included in the recipe, the darker the crust of the bread, the harder the bread crumb, and the smaller the specific volume. The 10% faba bean starch-rich fraction substitution was an outlier to this trend, however. Its specific volume was higher than that of the substitution-free bread (Table 5). The resilience of the bread was also measured and showed no general correlation to substitution levels.
For the whole-wheat pan bread with faba bean starch-rich fraction, the hedonic sensorial evaluation showed that more than half of the participants found substitutions of 10% or 20% appealing; 42% of the participants were willing to buy the 20% substitution and 69% were willing to buy the 10% substitution. For the white sandwich bread, the hedonic sensorial evaluation showed that more than half of the participants were willing to buy breads with a substitution of 10% or 20% and they evaluated these substitutions as “acceptable”. Overall, the taste of the faba bean starch-rich fraction in the whole-wheat pan bread was less evident than the taste of pea starch-rich fraction in the white sandwich bread.
Figure 1: Slices of white sandwich bread with varying substitutions of yellow pea starch-rich fraction.
Figure 2: Slices of whole-wheat pan bread with varying substitutions of faba bean starch-rich fraction.
Conclusion and outlook
This experiment showed that the starch-rich fraction produced by the dry-fractionation of faba beans and yellow peas is suitable for substituting up to 20% of wheat flour in staple breads. The addition of pulse starch-rich fractions to wheat flour is a potential method to diversify and improve the nutritional profiles of the breads. The pulse starch-rich fractions add complex carbohydrates and diversify the protein quality whilst offering the benefit of being a clean label ingredient with comparatively mild processing. Bühler will continue to identify and develop applications for the co-products won by pulse protein fractionation as part of our ambition to add value and close food production chains already existing today, helping feed the growing world of tomorrow.