Impact of Modified and Native Starch on the Quality Attributes of Gluten-Free Bread

Sammanfattning

This study investigated the influence of various native and modified starches on the quality and staling behaviour of gluten-free bread. Four starch types: native wheat starch, cross-linked tapioca starch, fractionated native potato starch (FPS), and acetylated potato starch (Amylacetate) were evaluated by incorporating them into a standardized gluten-free bread formulation as the main starch source. Several gluten-free bread quality parameters were assessed, including pasting properties (RVA), gelatinisation and retrogradation characteristics (DSC), specific loaf volume, baking loss, crumb colour (L*a*b*), texture profile analysis (TPA), crumb and crust moisture content, and sensory perception through a ranked attribute test. The results demonstrated that the type of starch significantly affected all measured bread quality attributes. Wheat starch produced loaves with the highest specific volume and showed balanced textural properties with moderate firmness and cohesiveness. Amylacetate yielded similar texture and retrogradation behaviour to wheat, with lower firmness and retrogradation enthalpy than FPS, but its higher paste viscosity likely inhibited gas expansion during baking, resulting in lower loaf volume. FPS, despite achieving high specific volume, exhibited the most unfavourable textural qualities: high crumb firmness, low cohesiveness, and high retro-gradation enthalpy, indicating rapid staling due to amylopectin recrystallization and moisture immobilization. Tapioca starch, while yielding low volume bread, showed excellent resistance to staling, with the lowest crumb firmness and highest cohesiveness, though its unique chewy texture received mixed sensory ratings. A general correlation was observed between higher retrogradation enthalpy, crumb firmness, dryness, and poor sensory outcomes, supporting the role of amylopectin recrystallization in staling dynamics. However, exceptions such as the increased firmness in Tapioca bread without corresponding retrogradation enthalpy increases, suggested additional staling mechanisms, possibly linked to moisture redistribution or matrix densification. Additionally, Crumb moisture content did not directly correlate with firmness, highlighting that moisture availability for crumb plasticisation, rather than total moisture, influences texture. Overall, the findings underscore the importance of starch physiochemical properties and modification on both initial bread quality and shelf-life performance in gluten-free baking applications.