Title: Arabinoxylan content and characteristics during the preparation of pancakes Authors
Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 18, 2014
Publication Date: N/A
Interpretive Summary: Wheat end-use quality is heavily influenced by the non-starch polysaccharide molecules, arabinoxylans (AX). The high water-absorption capability of AX molecules creates differing water relationships in various types of wheat-based products. While the influence of AX content has been heavily studied in both hard and soft wheat products, the structure of these AX molecules has not received the same level of examination. The objective of this study was to evaluate the content and structure of AX molecules throughout the pancake-baking process in order to further understand the intermolecular relationships that AX molecules participate in. Arabinoxylan molecules can be quantified into three categories: total AX content (TAX), water-extractable (WEAX) content, and water-unextractable (WUAX) content. The content and structure of these three categories was assessed in flour, pancake batter, and cooked pancakes for both refined and wholemeal flour samples from five different varieties representing different market classes of wheat. The AX content and structural patterns differed between wholemeal and refined flour pancake samples. In wholemeal pancakes, TAX content of flour was most detrimental to pancake quality, as assessed by diameter. In refined flour pancakes, the WEAX content of flour exhibited the greatest negative influence on pancake quality. This study highlights the need for further examination of both content and structure of AX molecules throughout the baking process to better understand the complex intermolecular relationships in which AX molecules participate.
Technical Abstract: Arabinoxylans (AX) are well known to have a wide-ranging influence on wheat (Triticum aestivum L.) end-use quality and are associated with health benefits as the major fiber constituent in wheat. Arabinoxylan content and properties are often assessed in raw flour and slurries and then correlated with end-use quality. However, there is little information on the effects of processing on AX properties in a high water content, batter-based product, as well as the associations between AX properties and end-use quality in such products. The objective of this study was to track total and water-extractable AX (TAX and WEAX) content and determine changes in AX characteristics throughout the baking process of pancakes, a batter-based wheat product. The TAX and WEAX contents along with the arabinose:xylose (A/X) ratio were quantified in refined flour and wholemeal as well as batter and pancakes from two soft and three hard wheat varieties. ANOVA F values indicated that the variation in TAX content was influenced most by sample type differences (flour vs. batter vs. pancakes), whereas varietal differences were responsible for the greatest differences in WEAX. In separate analyses on refined and wholemeal flours, the highest F values were for variety WEAX. This was largely attributed to the higher WEAX content of the three hard varieties. TAX levels consistently increased from flour to batter to pancakes when using refined flour of all five varieties; the changes in TAX suggest a greater availability of TAX to hydrolysis resulting from the addition of other ingredients, mixing, and frying. TAX also tended to increase in processing wholemeal into batter in four of five varieties. WEAX levels generally increased slightly from flour to batter to pancakes in refined flour of all varieties; however, there was little overall effect of processing on WEAX levels in wholemeal. WEAX content in flour, batter, and pancakes of both refined flour and wholemeal was highly correlated with pancake volume in all sample types (flour, batter, pancakes) and varieties. Refined flour TAX was positively correlated with volume but pancake TAX was negatively correlated with volume; this shift was associated with increasing TAX levels during processing of refined flour. Our observations suggest moderate changes in wheat AX fiber properties during processing, and a positive association of WEAX levels with end-product volume in a batter-based product.