Effect of proteolytic bacteria on texture and colour quality of khanom ‐ jeen , traditional Thai fermented rice noodles

Abstract

Significance and Impact of the Study: The use of Enterobacter ludwigii strain SK01 as a proteolytic bacterial starter culture improved the quality of khanom-jeen noodles. Compared with khanom-jeen noodles produced without E. ludwigii strain SK01, those produced using this strain showed increased tensile strength, breaking length, brightness and whiteness. These findings will be useful for the development of specific and controllable methods for producing khanom-jeen noodles with desirable texture and colour. AbstractKhanom-jeen are traditional Thai fermented rice noodles with a characteristic flavour and texture. Based on their ability to hydrolyse rice proteins, five strains of proteolytic bacteria were isolated from fermented rice flour used to produce noodles in Thailand. Enterobacter ludwigii strain SK01 showed the highest degree of rice protein hydrolysis among the five strains and was selected as a starter culture for khanom-jeen production. The viable count of micro-organisms, acidity, pH, and protein and starch contents were compared throughout the fermented rice production with and without the SK01 strain. The pH of fermented rice increased on the first day of solid-state fermentation and subsequently decreased to 3Á7-3Á8 under both conditions. The protein content of rice significantly decreased from 80 to 18Á2 AE 0Á5 mg g À1 and 26 AE 0Á6 mg g À1 during fermentation with and without the SK01 strain, respectively. The tensile strength, breaking length, brightness, and whiteness, which are important factors for the texture and appearance of khanom-jeen, were improved using the SK01 strain to ferment rice. The results of this laboratory-scale study indicated that the use of the proteolytic SK01 strain in fermented rice production can improve the quality of khanom-jeen noodles.Letters in Applied Microbiology ISSN 0266-8254

Effect of Levilactobacillus brevis TISTR 860 and Lactiplantibacillus plantarum TISTR 951 on gamma‐aminobutyric acid content in fermented rice flour and rice noodles (Kanomjeen)

“…The result of protein content was decreased approximately 70 and 80%. In contrast, hardness and elasticity were increased (Shompoosang et al ., 2019). Moreover, the previous study indicated that during the fermentation process protein in rice endosperm, called protein body II, was removed.…”

“…The starch and protein ratio changing of fermented rice flour affected noodles’ quality (Shompoosang et al ., 2019). Protein composition changing related to forming properties of rice starch.…”