Effects of germinated brown rice slurry on the gel properties of hairtail surimi

A full analysis was conducted to investigate the impact of germinated brown rice slurry on the gel properties of hairtail surimi. The potential benefits were also addressed for the dysphagia in the elderly. Some parameters were then measured to determine the gel strength, texture profile, water-holding capacity, dynamic rheology, whiteness, water state distribution, protein secondary structure, microstructure, in vitro digestibility, and International Dysphagia Diet Standardization Initiative (IDDSI) level. The results demonstrated that there was a significant impact of germinated brown rice slurry on the gel strength of hairtail surimi. Moreover, the gel strength of hairtail surimi was reduced from (649.91±64.35) to (480.93±98.84) g·mm (P<0.05), indicating a substantial reduction. The gel strength was reduced to make the swallowing easier and safer, which was beneficial for individuals with dysphagia. Furthermore, the brown rice slurry shared a significant impact on various textural properties, such as hardness, cohesiveness, and chewiness. The brown rice group exhibited a significant decrease in hardness (from 585.63±61.35 N to 399.87±51.23 N), cohesiveness (from 81.14±10.23 N to 50.16±7.13 N), and chewiness (from 30.14±5.00 N to 18.31±3.97 N) (P<0.05), compared with the control group. The germinated brown rice slurry was then incorporated into the hairtail surimi, resulting in a softer and more easily chewable product. Interestingly, there was no significant effect on the whiteness value, despite these changes observed in the texture properties. The visual appearance of hairtail surimi failed to alter using germinated brown rice slurry. Furthermore, an augmentation in the water-holding capacity was observed after the addition of germinated brown rice slurry to hairtail surimi. The water-holding capacity exhibited a significant increase from (77.92%±0.73%) to (81.92%±1.40%) (P<0.05). The brown rice slurry was incorporated to induce the distribution of water states, thereby enhancing the protein-water binding. As such, the moisture was retained within the commonly-used product during cooking or processing, in order to prepare the meals for individuals with dysphagia. A more porous network structure was found to form the surimi gel after the addition of brown rice, compared with the control group. This structure was attributed to the unique properties of brown rice, such as the high fiber content and water absorption. The high porosity greatly contributed to the open gel matrix for better water retention. Furthermore, there were outstanding changes in the protein structure within the surimi gel. The α-helix structure content of myofibrillar protein significantly increased from (47.12%±1.09%) to (52.74%±1.65%) after the incorporation of brown rice (P<0.05). The functionality of protein was enhanced for the gel-forming ability. There was a significant decrease in the β-sheet structure content from (25.67%±0.84%) to (20.99%±0.65%) after the addition of brown rice into the surimi gel (P<0.05). A softer texture then improved the tenderness, due to the decreased protein aggregation. Meanwhile, the IDDSI level was determined to evaluate these structural effects on the practical applications in both groups. According to the IDDSI standards, the brown rice group reached level 5 consistency, representing the texture of a mildly thick liquid diet. While the control group achieved level 6 consistency, indicating the texture of a moderately thick liquid diet. In addition to structural modifications, aroma compounds also exhibited notable differences between both groups after sensory analysis. The inclusion of germinated brown rice slurry led to significant increases in the various aroma compounds, including aldehydes, ketones, alcohols, and esters (P<0.05). There was a positive contribution towards flavor perception. Therefore, the germinated brown rice slurry was incorporated to enhance the textural attributes for the overall sensory, in order to enrich the aroma profiles. An optimal amount of germinated brown rice slurry can be expected to soften the gel characteristics of hairtail surimi. These findings can provide theoretical support and reference for the development of surimi-based elderly food products.