• Food Science and Biotechnology
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• v.16 no.3
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• pp.329-336
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• 2007

Caking has been a serious problem in food, feed, pharmaceutical, and related industries, where dry powdered materials are produced and/or utilized. Caking of dry food powders occurs when water is redistributed or absorbed by the powders during processing and storage. The powders become sticky when their surfaces are mobilized by water, resulting in inter-particle binding, formation of clusters, and inter-particle fusion, which lead to caking. As a result of caking, the solubility of the powdered materials may decrease, lipid oxidation and enzymatic activity may increase, and sensory qualities such as flavor and crispness may deteriorate. Caking may also lead to microbial growth. For consumers, caking of powder products is a sign of poor quality and possible food safety problems. This paper provides a review of factors affecting caking, caking mechanisms, and analysis of caking based on previous studies.

• Korean Journal of Food Science and Technology
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• v.26 no.3
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• pp.305-309
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• 1994

Precooked powder of redbean porridge (RP) was prepared by the series of process extrusion, drying, milling and blending with a mixture of whole redbean flour and corn starch and others. The optimum process and quality of products for RP were investigated. After extrusion under the moisture content 24 to 26%, twin screw speed 350 rpm, extrusion temperature 150 to $155^{\circ}C$ and feed rate 60 kg/hr, the product had a higher quality with its natural redbean flavor/color. During the extrusion process, extrusion temperature and specific mechanical energy increased from 150 to $198^{\circ}C$ and from 134 to 144 kwh/ton respectively, as the amount of addition water decreased from 6 to 2 kg/hr. By the hot air drying of redbean extrudate (RE). it could be dried below to 4% moisture content, of which level considered as an optimal moisture content for anti-caking of the powdered product, at $80^{\circ}C$ for 4hrs and at $100^{\circ}C$ for 1.5 hrs respectively. In the sieve analysis of extrudate powder, when the product milled through a mesh size of 0.5 mm or 1.0 mm, about 80% or 65% of the feed was passed a 65 mesh screen respectively. Moisture absorption of final blended products was formed a cake under 100% of relative humidity after 13 hrs of storage. As the amount of RE powder reduced, the flavor score of products decreased by sensory evaluation of products prepared by the different ratio of RE powder, corn starch and sugar.