Insight into the mechanism of myofibrillar protein gel improved by insoluble dietary fiber

•SIDF significantly improved the gel strength and WHC of MP gels.•Water channels in the pure MP gel deteriorated the integrity of the gel network.•SIDF affected moisture distribution in the gel by drawing water from MP.•SIDF promoted β-sheets over α-helices and hydrophobic interactions in the MP.

The effects of sugarcane insoluble dietary fiber (SIDF) on water holding capacity (WHC), gel strength, microstructure, and secondary structures of myofibrillar protein (MP) gels were studied. The gel strengths and WHC were improved with the increase of SIDF content. Paraffin section showed that SIDF did not have direct contact with the MP and was simply trapped in the gel network. The SEM micrograph indicated that water channels appeared through the pure MP gel network, so the integrity of gel network and the gelation quality would de deteriorated. The SIDF acted as active dehydrating agent and change the water distribution. Hence, the water channels disappeared in the internal of heat-induced gelation, which promote to aggregate compact and well-linked gel structure. The analysis of T2 relaxation revealed that T21 relaxation time of MP gel decreased significantly with SIDF addition, which indirectly suggested that the gel with SIDF had better three-dimension network and could bind the water more firmly. Raman spectroscopic study showed the SIDF addition resulted in the left shift and right shift of characteristic peak in Amide I and Amide III of the gelation, respectively. Moreover, the intensity of characteristic peak in aliphatic residues band also had a significant decrease. The changes of Raman spectroscopy reflected the SIDF addition have the positive effect on forming firm and compact MP gel.

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