Effects of pea fiber additive amount on freeze-thaw stability of 3D printed pre-emulsified minced pork products

Repeated freezing-thawing cycles can often occur during storage, transportation, and sales of emulsified meat products. Ice crystals produced by repeated freezing-thawing cycles can destroy the structures of muscle fibers and meat proteins, thus resulting in water loss and quality deterioration of meat products. Fortunately, dietary fiber with strong water absorption can be expected for the water retention of frozen-thawed meat products. Therefore, this study aims to investigate the effect of the pea fiber on the freezing-thawing stability of 3D-printed meat mince cubes. The rheometer, color difference meter, texture meter, and TBARS were also utilized to examine the products. The samples were taken as the 3D printed meat mince cubes only filled with high internal phase Pickering emulsion (P), and the meat mince cubes without Pickering emulsion (N) as the control. The results showed that the apparent viscosity and viscoelasticity (G' and G") of minced meat filled with Pickering emulsion were proportional to the addition of pea fiber. Once the addition of pea fiber increased to 2% (PPF2) or more, the G' and G" of minced meat were higher than those of P and N minced meat. The viscosity and mechanical strength of emulsion mince were significantly improved after the addition of pea fiber. The shape preservation of printed products was also obtained after that. However, the printed meat mince cubes collapsed, when the added amount of pea fiber was more than 2%. Consequently, the excessive addition of pea fiber interfered with the formation of muscle gel network through steric hindrance, thus resulting in reduced network connectivity. The printing accuracy of minced meat was also reduced at the same time. There was a decrease in the shape-holding capacity of printed meat mince cubes under freezing-thawing cycles. Compared with the P and N meat mince cubes, PPF2 meat mince cubes shared the best shape-holding capacity under the same freezing-thawing treatment. The thawing loss rates of PPF2 meat mince cubes were 21.7% and 23.04% lower than that of N and P meat mince cubes, respectively; while its shrinkage rates were 24.88% and 26.26% lower than that of N and P meat mince cubes, respectively. The variation was attributed to the strong water-binding capacity and water-absorbing expansion of pea fiber. There was no significant difference in the L*, a*, and b* values of P and PPF2 meat mince cubes (P>0.05). The addition of pea fiber shared no change in the color stability of meat mince cubes that were filled with Pickering emulsion. In addition, there was a close correlation between the ice crystal void and TBARS values of P and PPF2 meat mince cubes. A significantly better quality was achieved in the P and PPF2 meat mince cubes, compared with the N meat mince cubes (P＜0.05). The addition of Pickering emulsion and pea fiber shared a positive effect on the limiting growth of ice crystals. It also suggested that the addition of pea fiber shared the protective effect of the interfacial protein film on the internal oil in Pickering emulsion. In general, pea fiber can be expected to effectively improve the freezing-thawing stability and quality of 3D-printed pre-emulsified meat products.