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United States Department of Agriculture

Agricultural Research Service

Title: Effects of Jet-Cooking Conditions Upon Intrinsic Viscosity and Flow Properties of Starches

item Dintzis, Frederick
item Fanta, George

Submitted to: Journal of Applied Polymer Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 27, 1996
Publication Date: N/A

Interpretive Summary: Steam jet-cooking of starch, a method of using steam to rapidly cook starches, has significant industrial applications and has been known for many years. However, very little information about applying this technique to starch processing is in the literature. This work provides basic information about the application of jet-cooking to starches. This information is helpful to industrial starch consumers and will provide additional encouragement to expand the use of starch.

Technical Abstract: This work examined the sensitivity of intrinsic viscosity values of jet-cooked waxy maize starch to initial pH conditions and the effects of jet-cooker steam pressure parameters upon the intrinsic viscosity and flow viscosity values of four jet-cooked starches. Flow viscosities of the 10 wt.% cooked starches and intrinsic viscosities in 90%DMSO-H2O were lowest when mixing and turbulence during steam jet-cooking was increased (i.e., by adjusting steam line pressure vs. pressure within the cooking chamber to allow greater amounts of steam to flow through the apparatus). The percent decreases of intrinsic viscosity caused by the most severe cooking conditions compared to gentle cooking conditions were 52, 45, 32, and 12 respectively, for waxy maize, waxy rice, normal maize, and 70% high amylose maize starches. Initial pH values, from 3 to 10.5, of waxy maize starch had minor effects upon the intrinsic viscosity of the jet-cooked material.

Last Modified: 4/18/2015
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