Structural and in vitro starch digestion of wheat flour noodles by calcium mediated gelation of low methoxyl pectin

The effects of pectin addition with low degree esterification on wheat noodles' physicochemical properties such as texture and in vitro starch digestibility were investigated. Wheat flour was incorporated with low methoxyl pectin (LMP) at five levels: 0%, 0.5%, 1%, 2% and 4% w/w in calcium fortified wheat noodles. As LMP incorporation increased to 4 % w/w, noodle water absorption declined, due to formation of LMP gels. Noodles textural results revealed an increase in hardness, gumminess, cohesiveness and adhesiveness due to the increase in noodle thickness which corresponded well with noodle microstructure results. Rheological measurements showed an increase in wheat noodle viscoelastic properties as a result of addition of LMP. Similar results are also shown on the pasting profiles, where peak, trough and final viscosity were raised with the incorporation of LMP. Overall findings showed the incorporation of LMP was able to lower the in vitro starch digestibility, where addition of 2 % w/w resulted in the highest reduction. These results successfully indicated the LMP's potential to be used as an ingredient in carbohydrate dense foods such as wheat noodle to retard starch digestion.