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United States Department of Agriculture

Agricultural Research Service

Title: Application of An in Vitro Digestion/caco-2 Cell Culture Model to Determine Optimal Ascorbic Acid to Fe Ratio in Commercial Infant Rice Cereal

Authors
item Glahn, Raymond
item Lee, Olivia - CORNELL UNIVERSITY
item Miller, Dennis - CORNELL UNIVERSITY

Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 31, 1999
Publication Date: N/A

Interpretive Summary: The objectives of the present study were to determine if adding ascorbic acid (AA) to infant cereal enhances iron availability from the cereal, and if so, what is the optimal ratio of AA to Fe to maximize Fe availability. In addition, we sought to determine if mixing of infant cereal with apple juice fortified with the RDA of AA (60 mg),increases Fe availability relative to mixing the cereal with water. A cell culture model was used to assess Fe availability from commercial infant rice cereal. This model is rapid, inexpensive and has been found to be representative of human studies. It utilizes methods which simulate digestion of the food while in the presence of human intestinal cell cultures. Measurement of Fe uptake by the cells was used to determine Fe availability from the food. Ascorbic acid (AA) was added to the cereal at AA to Fe molar ratios of 0.8:1, 1.2:1, 1.6:1, 2.0:1 and 2.4:1. Iron uptake into intestinal cells increased at the lowest AA:Fe ratio of 0.8:1 and maximal Fe availability was reached at an AA:Fe ratio of 1.6:1. Ratios greater than 1.6:1 do not provide any increased benefit; however, this research indicates that AA:Fe greater than 1.6:1 may be desirable as some AA can be lost in processing. Mixing of apple juice (fortified with AA) with rice cereal to approximate an AA:Fe of 1.2:1 did not enhance Fe availability. These results suggest that the AA present in the apple juice was broken down or that factors were present in the apple juice which offset the promotional effects of AA. This work demonstrates how this in vitro system can be used to refine and develop commercial food products.

Technical Abstract: The objectives of the present study were to determine if adding ascorbic acid (AA) to infant cereal enhances iron availability, and if so, what is the optimal ratio of AA to Fe to maximize Fe availability. In addition, we sought to determine if mixing of infant cereal with apple juice fortified with the RDA of AA (60 mg), increases Fe availability relative to mixing the cereal with water. An in vitro digestion/cell culture model (Glahn et al., 1998b) was used to assess Fe availability from commercial infant rice cereal. Caco-2 cell ferritin formation following exposure to cereal digests was used as a measure of Fe availability. The rice cereal was fortified with elemental Fe (Fe0) at a level of 542 ug Fe/g of cereal. Ascorbic acid (AA) was added at AA to Fe molar ratios of 0.8:1, 1.2:1, 1.6:1, 2.0:1 and 2.4:1. Caco-2 cell ferritin formation increased at the lowest AA:Fe ratio of 0.8:1 and maximal Fe availability was reached at an AA:Fe ratio of 1.6:1. Ratios greater than 1.6:1 do not provide any increased benefit; however, this research indicates that AA:Fe greater than 1.6:1 may be desirable as some AA can be lost in processing, provided that organoleptic problems can be avoided. Mixing of apple juice (fortified with AA) with rice cereal to approximate an AA:Fe0 of 1.2:1 did not enhance Fe availability. These results suggest that the AA present in the apple juice was oxidized or that factors were present in the apple juice which offset the promotional effects of AA. This work demonstrates how this in vitro system can be used to refine and develop commercial food products.

Last Modified: 12/22/2014
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