PHMG Preservative for Citrus Sour Rot Control
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Solution Overview
Problem
Current methods for controlling citrus sour rot in 'Shatang' mandarin fruits are inefficient, particularly during storage, due to the limitations of existing chemical bactericides, which often leave residues and pose safety concerns, and the disease incidence rate has been high, impacting the fruit's storage and economic value.
Innovation Solution
The use of polyhexamethylene guanidine hydrochloride (PHMG) as an antifungal agent, combined with other bactericides, to create a preservative that effectively inhibits the growth of Geotrichum candidum, significantly reducing the incidence of sour rot in citrus fruits during storage and transportation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional chemical bactericides (carbendazim, mildothane, imazalil, guazatine) are used to control citrus sour rot, then the decay control effectiveness is improved, but pesticide residues and safety issues worsen
Solution Approach 1:
The patent changes the chemical composition parameter by replacing conventional bactericides with PHMG (polyhexamethylene guanidine hydrochloride), which has different chemical properties - it is a polymer that is less prone to being absorbed by animals, has greatly reduced toxicity, and is actually at non-toxic level with LD50 of 25,000 mg/kg to mice, while maintaining or improving decay control effectiveness
Solution Approach 2:
The patent uses PHMG as a disposable preservative treatment that provides effective protection without requiring long-term safety monitoring or leaving harmful residues, replacing the need for persistent chemical bactericides
2Reliability
If low-temperature storage combined with chemical bactericides is used to control citrus decay, then the decay control effectiveness is improved, but the complexity of storage measures worsens
Solution Approach 1:
The patent extracts and eliminates the low-temperature storage requirement from the preservation system, achieving effective decay control through PHMG treatment alone at normal temperature storage conditions, thereby simplifying the storage infrastructure needed
Solution Approach 2:
The patent introduces PHMG as an intermediary substance that mediates between the fruit and decay pathogens, providing protection without requiring extreme storage conditions or complex combined treatment systems
3Reliability
If Guazatine is used to control sour rot in citrus, then the control effectiveness is improved, but the safety and applicability worsen due to carcinogenic risk and pesticide residues
Solution Approach 1:
The patent changes the chemical safety parameter by substituting Guazatine with PHMG, which has fundamentally different toxicity characteristics - PHMG is a polymer with greatly reduced absorption by animals and non-toxic levels, making it safe for use while maintaining sour rot control effectiveness
Solution Approach 2:
The patent adopts PHMG as a safe, single-use preservative that provides effective protection without the long-term safety concerns and regulatory restrictions associated with Guazatine, enabling broader applicability
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 preservative formulation with PHMG and other bactericides reduces the sour rot incidence in 'Shatang' mandarin fruits to less than 10% after 45 days of storage at normal temperature, compared to over 50% in untreated controls, thereby enhancing the economic value and storage stability of citrus fruits.
Implementation Method 1
PHMG can efficiently kill bacteria by attacking the cellular wall and cytoplasma membrane systems. PHMG can rapidly break through cytoplasma membranes when it combine with the fatty acids in phospholipid of cell membrane, breach nuclei of cells of the pathogenic bacteria, enable cell inclusion of the pathogenic bacteria to outflow.
Data Source
AI summary
The use of polyhexamethylene guanidine hydrochloride as preservative for preventing and controlling citrus sour rot and its application are disclosed by the present invention. The citrus preservative calculated by 100% total mass fraction comprises 0.05%-0.5% polyhexamethylene guanidine hydrochloride, 0.05%-0.2% of one or more selected from the group consisting of a mixture of several of the following: 0.05%-0.2% imidazole fungicidebactericide, benzimidazole fungicidebactericide, pyrimethanil, fludioxonil and azoxystrobin, and 0.02%-0.15% polyethenoxy ether emulsion or quaternary ammonium salt emulsion, and the rest is water. The citrus preservative can significantly inhibit the decay of citrus fruit such as Citrus microcarpa during storage, especially the incidence of sour rot. So the commercial value of citrus is obviously increased.