18A-7

R. Rodriguez-Rivera¹, E. POLANCO-LUGO², A. Corona-Cruz², and E. Campechano-Carrera. (1) Facultad de Ingenieria Quimica, Universidad Autonoma de Yucatan, Av. Juarez No.421 Cd. Industrial, Merida, 97288, Mexico, (2) Dept. of Food Science and Technology, Universidad Autonoma de Yucatan, Av. Juarez No. 421, Cd. Industrial, Merida, Yucatan, 97288, Mexico

The nutrition and thermal properties of starch are largely conditioned by its source, and changes are generated during the food process and storage. Some of those changes give origin to amylase-resistant starch (RS) offering beneficial contributions to human physiology and the food industry. However, one adverse aspect of RS is its low stability at high temperatures. RS content of starch isolates can be increased by heating and cooling cycles generally referred to as annealing. The objective of this study was to evaluate the nutritional quality (RS content and in vitro digestibility) of native (N), retrograded (R) and retrograded-debranched-annealed (RDA), starch from the legumes Vigna unguiculata L. Walp and Phaseolus lunatus L; also use differential scanning calorimetry (DSC) to thermally analyze the resulting RS-containing material before and after RDA to evaluate its stability. A factorial design was used to evaluate time-temperature storage; the following response variables and levels were used: type of legume (Pl and Vu), time of storage (5 and 10 days), and temperature (25, 4 and -15ºC). The treatment with the highest RS content for each legume was enzymatically debranched (RSE) and annealed (RSA) with the purpose of increasing RS content. The fractions of RS were analyzed according to their nutrimental composition and thermal stability. The native starches of Pl and Vu presented total starch contents of 98.75 and 98.22%, as well as percentages of amylose in order of 33.18 and 30.93, respectively. With the RSE and RSA processes, values of 37.89% (Pl) and 32.83% (Pl) RS were obtained, respectively. The enzymatic debranching was the best strategy for the generation of the fraction resistance; however, the annealed process favoured the thermal stability according to the thermal analysis (DSC).

Session 18A, Carbohydrate: General
2:00 PM - 5:30 PM, Sunday PM Room Hall I-2

2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana