Effect of roasted pea flour/starch and encapsulated pea starch incorporation on the in vitro starch digestibility of pea breads

Citation

Lu, Z.H., Donner, E., Liu, Q. (2018). Effect of roasted pea flour/starch and encapsulated pea starch incorporation on the in vitro starch digestibility of pea breads. Food Chemistry, [online] 245 71-78. http://dx.doi.org/10.1016/j.foodchem.2017.10.037

Plain language summary

Bread is a staple food which is consumed all over the world. However, due to the low slowly digestible starch (SDS) and resistant starch (RS) content, most wheat-based breads are high glycemic index (GI) foods. Pea can be an alternative ingredient to make relatively low GI bread. The challenge is how to retain or enhance the amount of SDS and RS in the finished pea bread after processing. This research paper is the first report on roasting and encapsulation synergistically applied to pea flour/starch for developing new food ingredients with a better flavor and enhanced SDS and RS fractions. These physically modified starch products would be favored by consumers. Moreover, there is no published report on incorporating roasted flour/starch and/or encapsulated pulse starch in foods, especially in bread making.
In this study, oven or microwave roasting and alginate encapsulation of pea flour and starch to produce novel pea ingredients for enrichment of SDS and RS content in pea bread were investigated. Pea flour treated either by oven roasting (160°C, 30 min) or by microwave roasting (1.1 kW, 6 min) effectively retained its low starch digestibility similar to its native form (~ 25% SDS; ~ 60% RS). When oven roasting was applied to pea starch, SDS content increased triply compared to the fully boiled counterpart. Alginate encapsulation effectively controlled carbohydrate release to simulated gastric, intestinal and colonic fluids, and thus largely enriched the SDS and RS fractions in starch. Pea bread containing up to 38% of encapsulated roasted pea starch not only provided high SDS and RS fractions (24% SDS and 30% RS) compared to a white bread control (0% SDS and 3% RS), but also provided an acceptable palatability.
The replacement of wheat flour completely by pea flour for bread making would largely promote pea utilization, and also produce a healthy and gluten-free alternative which is in high demand by increasingly diagnosed celiac disease patients, as well as those with wheat allergies and gluten sensitivity.

Abstract

Oven or microwave roasting and alginate encapsulation of pea flour and starch to produce novel pea ingredients for enrichment of slowly digestible starch (SDS) and resistant starch (RS) content in pea bread were investigated. Pea flour treated either by oven roasting (160 °C, 30 min) or by microwave roasting (1.1 kW, 6 min) effectively retained its low starch digestibility similar to its native form (∼25% SDS; ∼60% RS). When oven roasting was applied to pea starch, SDS content increased triply compared to the fully boiled counterpart. Alginate encapsulation effectively controlled carbohydrate release to simulated gastric, intestinal and colonic fluids, and thus largely enriched the SDS and RS fractions in starch. Pea bread containing up to 37.5% of encapsulated roasted MPS pea starch not only provided high SDS and RS fractions (23.9% SDS and 30.2% RS) compared to a white bread control (0.2% SDS and 2.5% RS), but also provided an acceptable palatability.

Publication date

2018-04-15

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