Resistant starch formation does not parallel syneresis tendency in different starch gels

The retrograded resistant starch contents (RS-III) and syneresis indices of cold stored starch gels were compared. Isolated starches from three cereals (maize, sorghum and rice), two legumes (jack bean and lentil) and arracacha roots (Arracacia xanthorrhiza) were hydrated and gelatinized by boiling. Drained gels were stored for 24 h at 4 degreesC before the analyses. Neither apparent amylose contents nor water exclusion values showed clear correlation with RS-III content in the overnight stored gels. Legume starches reached 6-7% (dmb) RS-III levels, while the lowest values (2-3.6%) were recorded for maize, rice and arracacha samples. Jack bean starch gels showed the greatest syneresis indices, followed by the cereals, arracacha and lentil preparations. Data support the perceived idea of different mechanisms governing syneresis and RS-III formation in gelatinized starches. (C) 2002 Elsevier Science Ltd. All rights reserved.