Persimmon Slices Drying via Microwave Air-Jet and Ultrasonic De-astringency
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Solution Overview
Problem
Current methods for producing persimmon slices face issues such as browning, uneven de-astringency, poor drying uniformity, long drying times, and low production efficiency, leading to suboptimal quality and limited scalability in persimmon product variety and market availability.
Innovation Solution
A three-dimensional microwave air-jet drying method involving grading, peeling, water jet cutting with an anti-browning solution, microwave heating, vapor de-astringency, hot-air reverse primary drying, and negative pressure intermittent secondary drying, utilizing a combination of ultrasonic waves and citric acid vapor to achieve uniform drying and efficient nutrient preservation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional high-temperature baking or low-temperature freeze-drying is used, then drying can be achieved, but drying time is long and production efficiency is low
Solution Approach 1:
The patent applies microwave heating to change the thermal parameters during drying, enabling rapid internal heating that simultaneously achieves high drying efficiency and short drying time, overcoming the trade-off between productivity and time loss inherent in traditional thermal drying methods
Solution Approach 2:
The patent uses periodic intermittent drying cycles with microwave heating followed by rest periods, allowing moisture redistribution while maintaining high overall drying rate, thus achieving both short drying time and high production efficiency
2Manufacturing precision
If traditional drying technology is used, then drying can be performed, but temperature uniformity is poor causing inconsistent surface evaporation and internal moisture migration rates
Solution Approach 1:
The patent replaces conventional thermal conduction-based heating with microwave electromagnetic field heating, which penetrates uniformly throughout the persimmon slices and generates heat internally via dielectric heating, achieving superior temperature and moisture distribution uniformity during drying
Solution Approach 2:
The intermittent drying process allows periodic moisture redistribution throughout the material, preventing surface hardening and ensuring uniform moisture migration from interior to exterior, thereby achieving consistent drying quality
3Productivity
If traditional soaking de-astringency technology is used, then de-astringency can be achieved, but the speed and concentration of de-astringency liquid permeation decrease due to the fence effect of persimmon cells
Solution Approach 1:
The patent uses ultrasonic waves to change the physical state and permeability of persimmon cell structures, breaking down the fence effect and enabling rapid penetration of de-astringency liquid throughout the tissue, achieving high efficiency and fast permeation speed simultaneously
Solution Approach 2:
Ultrasonic vibration creates cavitation and mechanical disruption of cell walls, opening pathways for de-astringency liquid to penetrate rapidly and uniformly throughout the persimmon slices, overcoming the slow permeation limitation of traditional soaking methods
4Ease of manufacture
If cut surfaces are exposed to air during slicing, then slicing can be performed, but browning occurs due to mechanical damage and catalytic oxidation by polyphenol oxidase
Solution Approach 1:
The patent creates an inert or reduced-oxygen environment during slicing and initial processing using vacuum or nitrogen atmosphere, preventing oxidative browning of cut surfaces while maintaining ease of slicing operations
Solution Approach 2:
The patent applies preliminary anti-browning treatments such as blanching, chemical dips, or enzyme inactivation before slicing to prevent polyphenol oxidase activity, allowing easy slicing without subsequent browning discoloration
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 method effectively inhibits browning, ensures uniform de-astringency and drying, significantly reduces drying time, and enhances the quality and rehydration properties of persimmon slices, making it suitable for large-scale continuous production while maintaining nutritional value.
Implementation Method 1
three-dimensional microwave air-jet drying of persimmon slices
Implementation Method 2
utilizing a combination of ultrasonic waves and citric acid vapor
Implementation Method 3
hot-air reverse primary drying
Implementation Method 4
negative pressure intermittent secondary drying
Data Source
AI summary
The present invention relates to a method for three-dimensional microwave air-jet drying of persimmon slices, comprising steps of grading and cleaning, slicing, microwave heating, steam de-astringency, hot-air reverse primary drying, negative-pressure intermittent secondary drying, cooling and packaging. In the present invention, high-temperature (60-70° C.) high-pressure annularly sprayed citric acid and 40% alcohol vapor (rotating at 360°) are adopted to remove astringency of persimmons, wherein high temperature causes more intense Brownian motion of liquid molecules; high pressure improves permeation and diffusion speed of de-astringency liquid in the persimmon slices; citric acid plays a membrane breaking role on persimmon cell membranes; and 40% alcohol vapor is allowed to rapidly diffuse into cells, so that tannin is polymerized into insoluble gel from a soluble state, thereby achieving a uniform and rapid de-astringency effect.