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United States Department of Agriculture

Agricultural Research Service

Title: Effects of Pearling on Falling Number and Alpha Amylase Activity of Pre-Harvest Sprouted Spring Wheat.

Author
item Hareland, Gary

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 3, 2002
Publication Date: April 1, 2003
Citation: HARELAND, G.A. EFFECTS OF PEARLING ON FALLING NUMBER AND ALPHA AMYLASE ACTIVITY OF PRE-HARVEST SPROUTED SPRING WHEAT.. CEREAL CHEMISTRY. 2003. VOL. 80:232-237.

Interpretive Summary: The presence of pre-harvest sprouted wheat is typically confirmed by the falling number (FN) test, which is an indirect measure of enzymatic degradation of the starchy endosperm. Wheat with FN values below 250-275 is often discounted at the time of sale. The intent of this investigation was to evaluate the effects of debranning or pearling on the flour quality traits of hard spring wheat. Wheat samples were rated as low, med-low, medium, med-high, and sound that exhibited a range in FN values from 62 sec to 425 sec. Samples were pearled for 30, 60, and 120 sec to remove portions of the outer bran layers before being milled. FN was highly correlated with alpha amylase enzyme activity in the med-low, medium, and med-high FN sample sets as pearling time increased. FN increased in the med-low, medium, and med-high FN samples by 128%, 123%, and 80%, respectively, after 120 sec of pearling. Pearling had no effect on flour FN of the low FN sample and little or no effect on FN and alpha amylase activity of the sound sample. FN was moderately to strongly correlated with Rapid Visco Analyzer, alveograph, and farinograph properties, and poorly correlated with protein content, flour yield, and bread loaf volume. In subsequent bread making studies, bread loaf volume and crumb characteristics of flour from pearled wheat were not significantly different from loaf volume and crumb characteristics of flour from the corresponding non-pearled wheat.

Technical Abstract: Pre-harvest sprouted wheat is often characterized by the falling number (FN) test. FN decreases in pre-harvest sprouted wheat as enzymatic degradation of the starchy endosperm increases. Wheat with FN values below 250-275 is often discounted at the time of sale. The intent of this investigation was to evaluate the effects of debranning or pearling on the flour quality traits of five samples of wheat rated as low, med-low, medium, med-high, and sound that exhibited a range in FN values from 62 sec to 425 sec. Replicates of each sample were pearled for 30, 60, and 120 sec to remove portions of the outer bran layers before being milled. FN was highly correlated with alpha amylase activity (r =>-0.97) in the med-low, medium, and med-high FN sample sets as pearling time increased. FN increased in the med-low, medium, and med-high FN samples by 128%, 123%, and 80%, respectively, after 120 sec of pearling. Pearling had no effect on flour FN of the low FN sample, but alpha amylase activity was significantly decreased. Pearling had little or no effect on FN and alpha amylase activity of the sound sample. FN was moderately to strongly correlated with Rapid Visco Analyzer, alveograph, and farinograph properties, and poorly correlated with protein content, flour yield, and bread loaf volume. In subsequent bread making studies, bread loaf volume and crumb characteristics of flour from pearled wheat were not significantly different from loaf volume and crumb characteristics of flour from the corresponding non-pearled wheat.

Last Modified: 11/28/2014
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