Honey-mediated aggregation of soymilk proteins

Abstract

Gluconic acid, the major organic acid in honey, is a partial hydrolysate of glucono-δ-lactone, typically used as a coagulant in preparing tofu. The present study aimed to examine the coagulation potential of five different types of honey at different concentrations, upon addition to soymilk. In some samples, aggregates formed in the upper layer at a higher honey concentration, while in others, aggregates precipitated at an intermediate honey concentration. Both phenomena were reproduced by adding different mixtures of glucono-δ-lactone and glucose, indicating that gluconic acid concentration and total sugar content of honey can trigger soymilk coagulation. Interestingly, honeys with a high concentration of gluconic acid showed a low total sugar content. Furthermore, in a trial product, the mixture of blended honey with soymilk was determined to be pasty. Our results indicate that honey can coagulate soymilk, which may provide a new and convenient method to prepare soymilk-based industrial products.

Direct comparison of the tofu-like precipitate formation by adding different coagulants: magnesium chloride and glucono-δ-lactone

“…Precipitates and supernatants were prepared from soymilk according to the methods previously described by previous studies ( Arii and Takenaka, 2013 ; Yang and James, 2013 ; Arii and Nishizawa, 2020 ), with minor modifications. Soymilk was incubated at 85 °C for 10 min MgCl 2 and GDL were dissolved in distilled water and used as coagulant solutions at various concentrations (0–200 mM).…”

“…GDL, an acidic coagulant, is spontaneously hydrolyzed in water to form gluconic acid ( Sawyer and Bagger, 1959 ); therefore, reducing the pH ( Chen et al., 2016 ). Consequently, the pH reduction leads to TLP formation ( Arii and Nishizawa, 2020 ) by decreasing the electrostatic repulsion between soymilk proteins during the tofu formation ( Cavallieri & da Cunha, 2008 ). However, tofu produced by adding GDL is harder than those produced by adding CaSO 4 ( Guo and Ono, 2005 ).…”

Development of Tofun: A new sweet confection made from soymilk and honey

“…Recently, it has been attracting increasing attention as a superfood (Carina et al, 2014;Khan et al, 2018). Interestingly, honey can coagulate soymilk proteins, which is used to make tofu (Arii and Nishizawa, 2020). The ability of honey to coagulate soymilk proteins depends on the concentration of gluconic acid (GA), which is the coagulating agent (Arii and Nishizawa, 2020).…”

“…Interestingly, honey can coagulate soymilk proteins, which is used to make tofu (Arii and Nishizawa, 2020). The ability of honey to coagulate soymilk proteins depends on the concentration of gluconic acid (GA), which is the coagulating agent (Arii and Nishizawa, 2020). The GA content ranges between 1.3 mg/g and 10.8 mg/g depending on the type of honey (Nishizawa et al, 2021).…”

“…The amount of honey added, is a chemically and economically important factor for the development of novel sweets (Arii and Nishizawa, 2020). An excessive amount of honey results in candies that are too sweet and expensive whereas a deficient quantity added to soymilk does not result in coagulation.…”