Investigation of tofu products coagulated with trimagnesium citrate as a novel alternative to nigari and gypsum: Comparison of physical properties and consumer preference

This paper investigates the potential of trimagnesium citrate (TMC) as an alternative tofu coagulant, comparing it with the traditional coagulants used in industry as a means to address shortcomings of the two most common traditional coagulants: nigari (NGR) which has a high cost, but good organoleptic properties, and gypsum (GYP) which is inexpensive, but yields an undesirable taste/texture. Yield, water-holding capacity (WHC), texture profile analysis (TPA), confocal microscopic analysis, and sensory evaluation were conducted to compare raw and cooked tofu made from different coagulants. Use of TMC had no effect on yield but did influence several textural properties. For example, hardness and chewiness of TMC-tofu were significantly lower than both traditional products, while the cohesiveness of TMC-tofu and NGR-tofu samples were similar, being slightly lower than the GYP-tofu values. The rate of centrifugal water expression had no difference among the coagulants, but WHC of TMC-tofu was lower than NGR-tofu but similar to GYP-tofu. Structurally, TMC-tofu was similar to NGR-tofu, having numerous, irregular-shaped, small pores. In sensory comparisons, panelists preferred raw TMC-tofu over NGR-tofu and cooked TMC-tofu over GYP-tofu. Therefore, TMC, at the 0.35% range used in this study, should easily be suitable to replace or supplement traditional coagulants.