Whole grain wheat
effects of peeling and pearling on chemical composition, taste and colour
The EU-project HEALTHGRAIN has suggested a new definition for whole grain which allows a small part of the grain to be removed during processing. By removing the outer part or the grain the hygienic quality will increase but it is not clear how the taste and colour is affected. So therefore in this study three different debranning methods, peeling, pearling and polishing, which remove the outer parts of the grains have been used on common and durum wheat. The dietary fibre and ash content, as well as germination was analysed in untreated, peeled, pearled and polished grains. The decrease in dietary fibre and ash was higher in grains that had been pearled compared to those that had been peeled or polished. With approximately 2% of the grain removed there was a 4.2 ? 12.2% decrease in dietary fibre content for the pearled samples while the peeled sample had a decrease of 2.4% and the content was not affected by polishing. Peeling seems to be a more gentle process compared to pearling and will preserve most of the dietary fibres and keep the aleurone layer intact which will give a more nutritious end-product. To get an indication of how the different milling techniques affects colour and taste of the end-product and if these processes are of interest as a raw material for the next generation of whole grain products, a small sensory test was performed on pasta produced in a pilot scale from unteated, pearled (?2.5%) and peeled samples. The sensory test was small but gave an indication that the pasta produced from wheat where approximately 2% of the grain had been removed tasted slightly better than the pasta made from untreated wheat. The colour analysis of the pasta flour showed that the flour got a brighter colour with a higher degree of removal with peeling or pearling. Bran from different producers was also analysed to investigate if there is a natural variation in dietary fibre content in wheat. The results obtained from this investigation on bran showed a wide variation of dietary fibre content from 37-50% and the ash content varied from 4-7%.