The potential of soybean curd residue and water fraction of dragon fruit peel in wet noodles formulation

• Okara flour and dragon fruit peels are studied as sustainable food ingredients • Okara flour is investigated in wet noodles formulation • Dragon fruit peels combined in enhancing wet noodles The potential of agro-industrial by-products in food products development have been reported for their nutritional composition. Soybean curd residue (okara flour - OF) and dragon fruit peels (DFP) have been known as a source of protein, fiber, and antioxidant compounds. Their potential in wet noodle formulation has never been investigated. The study aimed to investigate the potential of soybean curd residue, OF, and water fraction of DFP in wet noodles formulation. Four different levels of OF (0, 10, 20, and 30 %) and four different levels of DFP (0, 7, 9, and 11 %) was incorporated in wheat-based wet noodles. Physicochemical properties, sensory acceptability and antioxidant properties were investigated. The study showed that most impact was given by different levels of OF. The higher level of OF declined the moisture content and protein content significantly ( p < 0.05) from a range of 45–48 % to the lowest level at 31 % and from 6.7–8 % to 5 %, respectively. The ash content increased as the level of OF was higher from 0.27 % to the highest level at 0.63 %. All the formulated noodles had a desirable value of cooking loss (<10 %) although it increased from 6 % in control to 9 % in 30 % OF addition. Hedonic sensory acceptability revealed that up to 20 % OF addition generated the same level of acceptability as it was in control showing and the incorporation of 9 % DFP to the 20 % of OF addition had the highest score of sensory acceptability. Antioxidant activity revealed that the selected formula (20 % OF and 9 % DFP) had higher antioxidant capability against DPPH shown by the lower level of IC 50 . In conclusion, combination of OF and DFP can be expected as sustainable food ingredients in wet noodles formulation.