Effects of water, guar gum, potassium chloride, and drying methods on quality and rehydration time of instant fermented rice noodles

Summary Quick rehydration is the most important characteristic of instant noodles. This study investigated the effects of ingredients on the production and drying methods, the quality, and the rehydration time of instant fermented rice noodles. The dried fermented rice flour was mixed with different amounts of water (80%, 85%, and 90%), guar gum (0.5%, 1.0%, and 1.5%), and potassium chloride (1%, 2%, and 3%). The noodles were dried in a microwave vacuum oven and compared with drying in a hot air oven and a microwave continuous oven. The optimum contents of water, guar gum, and potassium chloride were 80%, 1.5%, and 2%, respectively, because water at 80% resulted in the shortest rehydration time and the highest firmness, guar gum at 1.5% could increase firmness and the water absorption ability to produce the highest cooking yield and firmness with the lowest cooking loss, and potassium chloride at 2% resulted in the shortest rehydration time. Microwave vacuum drying produced the fastest rehydration in hot water for 2 min and the quality of these rehydrated noodles was better than for the other tested drying methods. Microwave vacuum drying generated rapid heat that promoted flash evaporation of the vapour in the noodles, resulting in a porous structure.