10–12 May 2022
Izola
Europe/Ljubljana timezone

Application of ASCA to characterise effects of roasting temperature, -time and milling method on SWIR spectral data of whole and milled wheat

Not scheduled
20m
InnoRenew CoE (Izola)

InnoRenew CoE

Izola

Livade 6

Speaker

Ms Jana van Rooyen

Description

Dry thermal treatment to modify wheat starch has been increasingly investigated. Structural changes of starch in heat treated wheat affects the molecular order, pasting properties, and retrogradation (Van Rooyen et al., 2022). Analysis of variance simultaneous component analysis (ASCA) partitions variation and interprets these partitions with SCA (Smilde et al., 2005). ASCA was used to investigate the effect of roasting and milling on whole wheat and flour shortwave-infrared (SWIR) spectra by assessment of statistical significance and characterisation of the contributing spectral features. A full factorial experimental design included three roasting temperatures, three roasting times and two milling methods. SWIR spectral images (1000-2400 nm) were collected from roasted wheat and subsequent milled samples. The factors ‘roasting temperature’ and ‘milling method’ had significant effects (p<0.05) on the samples, visualised by SCA. ‘Roasting time’ was statistically not significant (p=0.06), however it could have notable effect in practice. The high temperature affected starch (i.e. partial gelatinisation) and protein (i.e. denaturation) structures to a greater extent compared to intermediate and low temperatures. The intermediate temperature affected starch structures and moisture content more compared to the low temperature. The most prominent difference between the two milling methods was observed as changes in starch, protein, moisture (Quadrumat) and fibre (Perten). The absence of bran particles in the Quadrumat milled flour was responsible for the difference in protein structures. Protein denaturation was confirmed by an increment in Rapid Visco Analyser (RVA) peak viscosity as roasting severity increased (1753-2036 cP). Changes in starch structures resulted from starch damage. ASCA applied to SWIR whole wheat and flour spectral data effectively characterised the significant effect of roasting on wheat starch and protein structures.

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