Ginger milk curd, also known as ginger-juice milk curd, ginger milk pudding or simply ginger milk, is a Chinese hot dessert originated in Shawan Ancient Town, Panyu District, Guangzhou in the Guangdong Province[1][2] in southern China. The main ingredients are ginger, milk, and sugar.[3] Water buffalo milk is used in the original recipe.

Ginger milk curd
Alternative namesGinger-juice milk curd, ginger milk pudding, ginger milk
TypePastry
CourseDessert
Place of originChina
Region or stateShunde
Main ingredientsGinger, milk, sugar
Ginger milk curd
Traditional Chinese
Simplified Chinese
Literal meaningGinger collides with milk

Method of preparation edit

First, cut a piece of old ginger into small pieces and finely grind the ginger. Then, squeeze the juice out by pressing the ginger through a sieve. Put the juice into a bowl. Next, bring the milk to a boil and dissolve sugar in milk. Take off heat and allow it to cool a little. If one is available, place a kitchen thermometer into the milk. The optimum curdling temperature is 70 °C (158 °F).[4] In the meantime, stir the ginger juice thoroughly. When the milk temperature decreases to around 70–75 °C (158–167 °F), pour the milk quickly into the middle of the ginger juice. Wait for two to three minutes. The milk will then be curdled, and may be eaten with a spoon.

Underlying biochemical principle edit

The most important part of the ginger in ginger milk curd is the ginger protease zingipain. This substance with molecular weight of 31 kDa is found with three forms of isoelectric point values around 5.58, 5.40, and 5.22, respectively. The three forms have very similar biochemical behavior, where the optimal proteolytic activity is 40–60 °C (104–140 °F) and maximum clotting activity at 70 °C (158 °F).[5]

Milk is a substance consisting mainly of milk fat globules and casein micelles in a continuous phase of water, sugar, whey protein and minerals. Casein micelles consist of mainly α(s1)-casein, α(s2)-casein, β-casein, and κ-casein, where hydrophobic α and β-casein are in the inner sub-micelle and hydrophilic κ-casein is in the outer part.

When the milk starts curdling, the curds are small, but as coagulation increases, curd size increases until the milk ends up with a tofu-like structure.[6] When the curdling occurs, the ginger protease cuts open the κ-casein so that the hydrophilic C-terminus and the hydrophobic N-terminus separate. This disrupts the stability of the casein micelle. In the hydrophobic effect, the hydrophobic casein coagulates.[7]

See also edit

References edit

  1. ^ "Ginger milk pudding". www.chinadaily.com.cn. Retrieved 29 October 2020.
  2. ^ Zhang, Tristin (14 August 2017). "Explore 800 Years of History in Guangzhou's Shawan Ancient Town". That's Online. Retrieved 29 October 2020.
  3. ^ "Ginger Milk Pudding, a Natural Custard". tastehongkong.com. 29 March 2011. Archived from the original on 25 August 2012. Retrieved 13 August 2012.
  4. ^ "Ginger Milk Pudding". marecipes.com. Retrieved 19 June 2015.
  5. ^ Huang, X.W.; Chen, L.J.; Luo, Y.B.; Guo, H.Y.; Ren, F.Z. (2011). "Erratum to "Purification, characterization, and milk coagulating properties of ginger proteases" (J. Dairy Sci. 94:2259–2269)". Journal of Dairy Science. 94 (8): 4242. doi:10.3168/jds.2011-94-8-4242.
  6. ^ Zeng J-chao (2008) Discussion on the Mechanism of Curd with Ginger Juice. Thesis
  7. ^ Zhang P (1999) Study on Milk Clotting of Ginger juice . China Dairy Industry 27:17–19.

External links edit