Effect of Fermented Lettuce Extract on Starch Retrogradation in Korean Rice Cake, Garaetteok

Abstract

Starch retrogradation, i.e., reassociation or recrystallization of gelatinized starch, affects the flavor and texture of food. To prevent starch retrogradation, various methods such as replacement of chemically modified starch and use of hydrolytic and branching enzymes or additives have been studied. However, the relationship between fermented products and starch retrogradation has been not studied. Here, we investigated the effect of fermented lettuce extract on the retrogradation of Korean rice cake, garaetteok using Rapid Visco Analyzer (RVA), differential scanning calorimetry (DSC), texture analysis, and scanning electron microscopy (SEM). Fermented lettuce extract reduced peak viscosity, trough viscosity, breakdown, and setback of rice flour, as determined using the RVA. DSC revealed reduced onset temperature, peak temperature, and enthalpy change of cakes prepared from flour treated with fermented lettuce extract during storage compared with those of an untreated control. The change in the hardness of the treated rice cakes during storage, as determined via texture analysis, was smaller than that in the control. The surface of the fermented lettuce extract treated–rice cakes was found to be less cracked and porous than that of the control, as determined via SEM. Collectively, these findings showed that starch retrogradation during storage was retarded in fermented lettuce extract treated-rice cakes compared with untreated rice cakes. Therefore, these results suggested that fermented lettuce extract prevents starch retrogradation, improves food quality, and could be used as a food additive to retard starch retrogradation in the food industry.