Natural preservatives can be extracted from many plants in nature. In recent years, people started from garlic, ginger and spices such as clove, cinnamon, nutmeg, potato foods to extract the effective components, these spices, itself has natural antibacterial effect, such as using alcohol as the solvent of spices extracts, for a variety of bacteria have strong bacteriostasis, moreover in bamboo leaf, lotus leaf, bitter melon, grape skin extract has certain antibacterial activity. The following lists the application of plant extracts commonly used as preservatives at home and abroad as well as in Ningshan National Holy Biology:
Garlic contains allicin, allicin and allicin, among which allicin and allicin are the main antibacterial ingredients in garlic. The latter is 50 percent as effective against bacteria as the former. The antibacterial mechanism of allicin may be that the oxygen atoms in its molecules combine with cysteine in bacteria so that it cannot be converted to cysteine, thus affecting the important REDOX reaction in bacteria. Garlic has obvious inhibition and sterilization effects on a variety of cocci and molds.
2. Perilla leaf extract
Perilla leaf distillate has a broad spectrum of antibacterial action, the main effective ingredients are Perilla aldehyde and citral, staphylococcus aureus, Streptococcus b, diphtheria bacillus, carbonizobacillus, Pseudomonas aeruginosa, bacillus subtilis and other significant inhibitory effect, Perilla leaf oil inoculation and natural pollution of mold yeast also has a significant inhibitory effect.
Forsythia extract has inhibitory effect on a variety of Gram-positive bacteria and negative bacteria, and can effectively prolong the shelf life of food. Its antibacterial ingredient is forsythia phenol. In Japan, forsythia extract has been widely used in food preservation as a natural preservative.
Pectin decomposition products also have antibacterial effect in acidic environment, mainly polygalacturonic acid and galacturonic acid with average degree of polymerization between 3 and 5. Their antibacterial activity is affected by pH, and the antibacterial activity is strong below pH6.0, pH>. 6.0 is low in antibacterial, generally added in food for 0.1% ~ 0.3%, it is mainly used in hamburgers, noodle soup, cream cakes and pickles, etc.
Tea polyphenols have a good anticorrosive effect on bacillus subtilis, Staphylococcus aureus, Escherichia coli, tomato ulceration, streptococcus caries and mucor, penicillium, trichoderma, anthrax bacteria, beer yeast has an inhibitory effect. In addition to the above mentioned, betaine, mannan, horseradish extract are both economical and efficient natural food preservatives.
Due to some characteristics of mannan itself, such as low solubility, poor stability of sol, good fluidity and so on, its application is limited. After modification to overcome the shortcomings, broaden the application scope of konjac. After modifying konjac glucomannan with benzoic acid or gallic acid, as meat preservative, it can inhibit the reproduction of oxygen - loving microorganisms and prolong the meat preservative period.