Freeze Coagulation Method for Tofu Texture Control
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Solution Overview
Problem
Conventional methods of producing bean curd result in products with either high water content and low protein content, leading to poor texture and flavor, or high protein content with rough texture and low water content, failing to meet consumer demands for diverse and appealing bean curd qualities.
Innovation Solution
A method involving cooling soybean milk, adding a coagulant, freezing the mixture, and then heating it, which allows for control of moisture content and coagulation rate to produce bean curd with a unique, glutinous texture and improved flavor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a fast-acting coagulant is used to coagulate soybean milk, then the coagulation rate increases and protein content improves, but the texture becomes rough and flavor deteriorates
Solution Approach 1:
The coagulation process is divided into two distinct stages: first, low-temperature coagulation forms an initial gel structure, then high-temperature coagulation completes the protein precipitation. This segmentation allows each stage to contribute differently - the first stage preserves texture while the second stage ensures complete coagulation and protein extraction
Solution Approach 2:
The invention changes the temperature parameter dynamically during coagulation. By maintaining low temperature (4-10°C) during the initial coagulation phase and then raising to high temperature (80-95°C) for the second phase, the process optimizes both texture formation and protein content, resolving the contradiction between coagulation speed and texture quality
2Quantity of substance
If mechanical compression is applied to reduce moisture content, then water release increases and protein concentration improves, but texture becomes rough
Solution Approach 1:
The invention utilizes phase transition of water during freezing to achieve moisture separation. When the coagulated soybean milk is frozen, water forms ice crystals that naturally separate from the protein matrix. Subsequent thawing allows controlled water release without mechanical compression, preserving the delicate texture while concentrating proteins
Solution Approach 2:
The invention replaces mechanical compression systems with a thermal field system. Instead of applying mechanical pressure to remove water, the process uses freezing and thawing cycles to achieve moisture separation through phase change, thereby eliminating the rough texture caused by mechanical compression while still achieving protein concentration
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method produces bean curd with enhanced texture, elasticity, and flavor, achieving a moisture content of 50-80% and a uniformly layered structure, addressing the limitations of existing bean curd production techniques.
Implementation Method 1
freezing the resulting mixture of the soybean milk and the coagulant of process 2) above
Implementation Method 2
heating the frozen soybean milk of process 3) above or curd after thawing
Data Source
AI summary
The present invention relates to a method for preparing tofu by using freeze coagulation and, more specifically, to a method for preparing tofu and tofu prepared by the preparation method, the method comprising the steps of: cooling soymilk to an appropriate temperature; adding an appropriate coagulant into the cooled soymilk; freezing the soymilk into which the coagulant has been added; and maintaining the temperature to be below the freezing point and heating the frozen material after a predetermined time. The tofu according to the present invention has excellent mouthfeel and flavor and can be prepared having a structure and physical properties differentiated from those of conventional tofu.