Frozen Sushi Packaging for Uniform Microwave Thawing
Solution Overview
Problem
Microwave thawing of packed frozen sushi products often results in uneven heating, where sushi materials are heated to undesirably high temperatures, impairing the taste and making it difficult to achieve the desired temperature range for both the rice section and the sushi materials.
Innovation Solution
A method involving a sushi product placed in a plastic box within a flexible microwave-safe packing bag, vacuum-sealed and frozen together, where microwave heating is used to bring the rice section temperature to 30°C or higher, followed by steaming with water vapor to evenly heat the sushi materials to between 15°C and 25°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If microwave thawing is used to quickly thaw packed frozen sushi, then thawing time is reduced, but the sushi materials are heated to undesirably high temperatures, impairing the taste
Solution Approach 1:
The sushi product is segmented into two distinct parts: the rice section and the sushi materials. By placing them in separate compartments within the packing bag, the invention enables selective heating during microwave thawing. The rice section can be heated to thaw and warm up, while the sushi materials remain in a cooler zone, preventing overheating and taste impairment.
Solution Approach 2:
Different regions within the packing bag are assigned different thermal properties and heating characteristics. The rice section is positioned to receive more microwave energy for efficient thawing, while the sushi materials are positioned in a region with lower energy absorption, creating a localized temperature gradient that prevents the sushi materials from reaching undesirable high temperatures.
2Productivity
If microwave heating is applied to thaw the entire sushi product uniformly, then thawing efficiency is improved, but the sushi materials become overheated while the rice section may remain underheated
Solution Approach 1:
By dividing the sushi product into separate compartments (rice section and sushi materials), the invention enables differential heating control. This segmentation allows the rice section to be heated more intensively for efficient thawing while the sushi materials are protected from excessive heating, achieving both high productivity and temperature precision.
Solution Approach 2:
The packing bag is designed with localized thermal zones where the rice section experiences higher heat transfer and the sushi materials experience lower heat transfer. This local quality differentiation ensures that each component receives the appropriate amount of heat for optimal thawing without compromising temperature uniformity across the entire product.
3Reliability
If the sushi product is vacuum-packed tightly to prevent contamination, then hygiene is improved, but microwave heating causes uneven temperature distribution
Solution Approach 1:
The vacuum packing is applied to the entire sealed bag containing both rice and sushi materials, maintaining hygiene through tight sealing. However, the internal segmentation into separate compartments allows microwave energy to penetrate and heat different regions differently, enabling uniform temperature distribution while maintaining the hygiene benefits of vacuum packing.
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
This approach ensures uniform temperature distribution in the thawed sushi product, maintaining the quality and taste by preventing overheating of the sushi materials and achieving the desired temperature range, making it easier to cut and serve.
Implementation Method 1
microwave heating is used to bring the rice section temperature to 30°C or higher
Implementation Method 2
steaming with water vapor to evenly heat the sushi materials to between 15°C and 25°C
Implementation Method 3
the packing bag, the box and the sushi product being frozen together in a unified form
Data Source
AI summary
A packed frozen sushi product comprising a vacuumed, frozen and hermetically sealed flexible plastic bag; an open-topped plastic box placed in the bag; and a frozen sushi product contained in the box; in the plastic bag, the box and the frozen sushi product being frozen together in a unified form, the packed frozen sushi product thereby being adapted for microwave cooking. Water vapor emanating from the sushi product in thawing is allowed to flow through a space formed around the sushi material to heat a shaped rice section and a material or materials, thereby diminishing unevenness in temperature distribution after thawing. By virtue thereof, a packed frozen sushi product suitable for mass production is provided.