Production of resistant starch (RS3) from edible bean starches

Abstract

No pulse-based resistant starch (RS) is available commercially although their high amylose content makes them a potentially suitable starch source for making RS. Therefore, to investigate their suitability for the production of RS, starch was isolated from pinto, black, great northern, and lima beans, and characterized to determine proximate composition and pasting properties. Amylose content of bean starches ranged from 30.37 to 33.25% and corn starch 24.20%. Pasting properties of bean starches were generally higher than corn starch. However, corn starch displayed a higher stability. Corn starch also produced a high setback and final viscosity was relative to its amylose content. Bean and corn starches were used to produce retrograded RS (RS3). Resistant starch 3 preparation included a heat–cold method, α-amylase method, and pullulanase method. Resistant starch 3 produced ranged from 14.86 to 29.67%. Heat–cold method produced a significantly lower percentage RS3 compared to the other two methods. There were no significant differences between the α-amylase and pullulanase methods. Practical applications The α-amylase method, a rarely used method for making resistant starch (RS), can produce the same yields of RS3 as the more commonly used pullulanase method. Therefore, food ingredient manufacturers are provided with an alternative effective process to produce RS3 from bean starches in cases where pullulanase is unavailable or otherwise inaccessible.