Proposal of mechanism of the freeze–thaw fractionation of 7S and 11S globulins in soymilk

Morita, Katsusada; Shimoyamada, Makoto

doi:10.1016/j.foodchem.2013.01.103

Cited by 19 publications

(15 citation statements)

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“…In addition, the formation of a lower layer from raw soymilk during the freeze-thaw process has recently been reported to arise from an increase in disulfide and/or hydrophobic interactions among proteins that have been concentrated by freezing (Morita and Shimoyamada, 2013). Therefore, we concluded that the particle sizes of the lower layers were increased through elevated concentration mediated by the formation of larger ice crystals.…”

Section: Resultsmentioning

confidence: 70%

Effects of Freezing Temperature on the Freeze-thaw Fractionation of Soymilk

Morita

Shimoyamada

Nakajima

2015

FSTR

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In this study, we investigated the effects of freezing temperature ( _ 10℃, _ 30℃, and _ 80℃) on the freeze-thaw fractionation of soymilk. The physicochemical properties of soymilk samples were analyzed after freeze-thawing and fractionation (upper and lower layers). The weight ratios, protein and lipid contents, and 11S/7S ratios of the upper layers were essentially equivalent to those of the lower layers, regardless of the freezing temperature employed. On the other hand, the particle size of the lower layer increased as the freezing temperature was elevated.However, when the lower layers were heated, the particle size distributions were again found to be equivalent across the various freezing temperatures tested. Furthermore, the heated lower layers exhibited similar soymilk calcium coagulability and texture of the produced tofu curd across the various freezing temperatures. These results suggested that the fractions obtained by the freeze-thaw fractionation of soymilk were unaffected by freezing temperature.Keywords: freeze-thaw, freezing temperature, soymilk, tofu curd IntroductionSoymilk is consumed as a healthful beverage, and is an important source of tofu curd (soybean curd). Therefore, the physical properties of tofu curds depend on the physicochemical properties of soymilk such as protein content (Toda et al., 2003; Toda et al., 2006) and the 11S/7S ratio (Saio et al., 1969;Kohyama et al., 1995; Yagasaki et al., 2000;Guo and Ono, 2005). However, the 11S/7S ratio in soymilk is dependent on the soybean variety (Toda et al., 2008). Thus, it is difficult to modify the 11S/7S ratio during preparation. Therefore, the utilization of individual 7S or 11S globulins obtained by suitable fractionation holds promise for improving the functional and textural properties of soybean products.We previously reported (Morita and Yokoi, 2011) a simple freeze-thaw method for the fractionation of these proteins in soymilk, and obtained two kinds of soymilks that had different protein and lipid contents as well as 11S/7S ratios. The tofu curd made from the 7S globulin-rich fraction was soft and smooth, whereas that made from the 11S globulin-rich fraction was firm.However, the effects of freezing temperature on the freeze-thaw fractionation of soymilk have not been reported. The formation of ice crystals is well known to be modified by the freezing rate (Ueno et al., 2004), and the morphology, size, and distribution of ice crystals formed during the freezing process of foods influence the quality of the resultant food products (Rahelić et al., 1985;Jibu et al., 2009; Ottestad et al., 2011). In addition, the investigation of freezing temperature is important to facilitate the commercial utilization of freeze-thaw fractionation of soymilk.In this study, we investigated the effects of freezing temperature on the freeze-thaw fractionation of soymilk, and evaluated the applicability of freeze-thaw fractionation of soymilk using a wide variety of freezing temperatures. K. Morita et al. 864 Materials and MethodsPreparation of s...

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Section: Resultsmentioning

confidence: 70%

Effects of Freezing Temperature on the Freeze-thaw Fractionation of Soymilk

Morita

Shimoyamada

Nakajima

2015

FSTR

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“…In addition, soymilk proteins aggregate upon heating (Guo et al, 1997). Accordingly, 7S forms soluble aggregates in raw soymilk upon freeze-mediated concentration (Morita and Shimoyamada, 2013), whereas 7S may form insoluble aggregates upon denaturation due to heating. Thus, the thermally denatured part of 7S and the lipid/protein complexes were considered to be interacted and aggregated upon freezemediated concentration, causing part of 7S to migrate to the lower layer.…”

Section: Resultsmentioning

confidence: 99%

“…The aggregates precipitate after thawing. The 7S globulin, which may form soluble aggregates due to its high hydrophilicity, is retained in the supernatant (Morita and Shimoyamada, 2013). (Guo et al, 1997;Ono, 2008).…”

Section: Resultsmentioning

confidence: 99%

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Effects of Pre-heating on Freeze-thaw Fractionation of Soymilk

Morita

Shimoyamada

Nakajima

2017

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Raw soymilk separates into two layers (upper and lower) upon freeze-thawing. In this study, we investigated the effects of heating (50 _ 95℃) before freezing on the freeze-thaw fractionation of soymilk. Proportion of the upper layer decreased as the heating temperature before freezing was elevated, and heating at 80℃ completely inhibited the fractionation. The amount of protein in the upper layer decreased with higher heating temperatures, and the 7S globulin contents in the lower layer increased simultaneously. The particle size of the upper layer decreased with increased heating temperatures, whereas the particle size of the lower layer increased at temperatures greater than about 70℃. These results suggested that the changes in soymilk fractionation are likely due to the liberation of 7S globulin from lipid/protein complexes upon heating, and interactions among the proteins and lipid/protein complexes caused by freeze-mediated concentration.

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“…The 11S globulin was found to comprise acidic and basic subunits (Ma et al, 2006;Jiang et al, 2006). Currently, studies on the 7S and 11S globulins are mainly focused on the effect of their concentration on the functional properties of soybean proteins (Cheng et al, 2006a(Cheng et al, , 2006bMujoo et al, 2003;Morita and Shimoyamada, 2013;Ortiz et al, 2004;Poysa et al, 2006), accumulation of globulin subunits, analysis of globulin subunit loss (Kawakatsu et al, 2010;Guo et al, 2006), methods of globulin extraction and separation (Molina et al, 2002;Liu et al, 2007;Ryan et al, 2005;Manjaya et al, 2007;Chen et al, 2012). The percentage concentration of each soybean globulin subunit is a hereditary trait of soybean cultivars, which is not liable to other factors (Cheng et al, 2006a).…”

Section: Introductionmentioning

confidence: 99%

Effect of phosphorus on the composition and accumulation of 7S and 11S globulin subunits during seed development of three soybean varieties

Han

Jie

Cai

2014

J. Soil Sci. Plant Nutr.

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Three soybean varieties (Dongnong 42, high-protein cultivar; Hefeng 25, medium-protein; and Dongnong 46, low-protein cultivar) grown under different P conditions were investigated in order to evaluate the effect of P on the composition and accumulation of 7S and 11S globulin subunits. The soybean seeds were planted in pots and fertilized with 0.033 g of N and K 2 O per kg soil. Four levels of P treatment were designed, which were P1, P2, P3 and P4 (i.e., 0, 0.033, 0.067, and 0.100 g of phosphorus pentoxide (P 2 O 5) per kilogram of soil). The composition of extractable proteins was determined by conducting SDS-PAGE. No significant differences were observed between the varieties with regard to the molecular weights of the globulin subunits. After the subunits were formed, their concentrations gradually increased under different P treatments, reached a peak at 70 d post-anthesis (DPA), and then declined during maturity. The concentrations of the 7S and 11S globulins and other subunits in Dongnong 42 and Hefeng 25 were the highest under the P3 treatment, while they were the highest in Dongnong 46 under the P2 treatment. Under the same P treatment, the concentrations were high in Dongnong 42 and low in Dongnong 46 and Hefeng 25. Significant differences were observed in the concentrations of 7S and 11S globulin subunits between the varieties and levels of P treatments, especially under the P3 treatment. Alpha subunit was mainly in relation with the P-nutrition in the three varieties. These findings suggested that the optimal combination of cultivars and P treatment levels could contribute to the increased concentrations of both soybean globulins and their subunits.

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Proposal of mechanism of the freeze–thaw fractionation of 7S and 11S globulins in soymilk

Cited by 19 publications

References 28 publications

Effects of Freezing Temperature on the Freeze-thaw Fractionation of Soymilk

Effects of Freezing Temperature on the Freeze-thaw Fractionation of Soymilk

Effects of Pre-heating on Freeze-thaw Fractionation of Soymilk

Effect of phosphorus on the composition and accumulation of 7S and 11S globulin subunits during seed development of three soybean varieties

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