Effect of extracts from clove and cinnamon on the Bacteriostasis of fruits and vegetables

Fresh fruits and vegetables are easy to be infected by pathogenic microorganisms and become rotten Postharvest preservation of fruits and vegetables has become a key research content in the world Chemical preservatives are widely used because of their simple use and remarkable effect However, with the popularization of scientific knowledge, people have a certain understanding of the harm of synthetic chemicals to human body The research, development and utilization of natural preservatives are the urgent needs of the market and consumers Chinese herbal medicine has the advantages of both medicine and food, long-term effect, etc some of them are proved by long-term experiments and modern microbial means that they can prevent the growth of pathogenic microorganisms, and are ideal natural antibacterial and antiseptic materials In this paper, the extract of clove and cinnamon and its bacteriostatic effect were studied and compared It provides a theoretical basis for the development of natural food preservatives 1 Materials and methods 1 1 Aspergillus niger, Aspergillus oryzae and yeast were all from the bioengineering Laboratory of Shanxi University 1.2 the sources of Chinese herbal medicine are clove, cinnamon, galangal, black plum and Anemarrhena, which are all purchased from the Chinese herbal medicine store; the mustard seeds are purchased from the agricultural material market 1.3 culture medium 1.3.1 chassian culture medium sucrose 30g; nan032g; KCI 5g; K ~ hp04.3hzd 1g; feso4.7h2o.o1g; mgso4.7hzd0 μ 5g; agar 15-20g; water 1000ml 1.3.2 maltose medium: peptone 10g; maltose 20g; yeast extract 5g; agar 15-18g; distilled water 1000ml 1.4 preparation of bacterial suspension The single colony was transferred to the liquid medium of chasser's, and the culture was shaken at 27 ℃ for 7 days Centrifugation, discard supernatant Add a small amount of sterile water and break it with ultrasonic to form a certain concentration of bacterial suspension The concentration of bacterial suspension used in the experiment was calibrated by 450 nm absorbance value, and the values of Aspergillus niger and Aspergillus oryzae were 0.157 and 0.216 respectively 1.4.2 take yeast suspension to activate, separate and shake it in maltose liquid medium at constant temperature of 28 ℃ for 28 H To form a certain concentration of bacterial suspension 1.5 preparation of Chinese herbal medicine extract crush the cleaned and dried Chinese herbal medicine samples and filter them with 40 mesh sieve 75% ethanol was used to prepare a solid-liquid ratio of 1:4 extraction system, which was extracted in water bath at 78 ℃ for 4 hours Filter, take supernatant and store at room temperature 1.6 Bacteriostatic Experiment (plate confrontation Culture) 1.6.1 mould Bacteriostatic Experiment Method: the solid chawski culture medium was dissolved and sterilized under high pressure, then poured into the plate, after cooling and solidification, two sterilized inoculation rings with diameter of 1 EM were symmetrically inserted 10 UL bacterial suspension was put into the middle part of the two inoculation rings of the culture dish and cultured in a constant temperature incubator at 28 ℃ for 2 days After the mold grew to a strain of 1 em, 200 UL of extract of traditional Chinese medicine was added into the inoculation ring, and sterile water and 75% ethanol were used as blank control Culture at 28 ℃ and observe at any time 1.6.2 yeast bacteriostasis experiment method: dissolve the solid maltose culture medium and sterilize it under high pressure, then pour it into a plate, after cooling and solidifying, connect 50 UL bacterial suspension, and evenly spread it with a scraper Two sterilized inoculation rings with a diameter of 1 EM were inserted symmetrically, and 200 UL of traditional Chinese medicine extract was added into each inoculation ring At the same time, sterile water and 75% ethanol were used as blank control Culture at 28 ℃ and observe at any time 2 Results and analysis 2.1 experimental content setting: this experiment takes sterile water as the blank and 75% ethanol as the control In order to ensure the accuracy and reliability of the experiment, blank and control experiments are added at the same time of Bacteriostatic Experiment 2.2 comparison of the bacteriostatic effect of different Chinese herbal medicines 6 kinds of Chinese herbal medicine extracts were used to screen the tested mold and yeast The experimental results showed that the six selected Chinese herbal medicines had different degrees of inhibition on mold and yeast, and the effect of Ding Xiang and cinnamon was excellent Among them, clove had the most significant inhibition effect on two kinds of mold, followed by cinnamon Cinnamon had the most significant inhibitory effect on yeast, followed by clove Although the other four Chinese herbal medicines have inhibitory effect on mold and yeast, the effect is not obvious, as shown in Table 1 2.3 inhibitory effect of Syringa on mold The results of plate culture showed that the inhibitory effect of Syringa extract on Aspergillus oryzae and Aspergillus niger was the most significant The experiment lasted for 30 days Before the addition of bacteriostatic, the strain grew well After the addition of bacteriostatic, the fungal spores were inhibited and shrunk, and there was no growth sign during the observation period The blank and control strains grew vigorously, and the spores grew all over the culture dish, as shown in Figure 1 2.4 the inhibitory effect of cinnamon on yeast the results of plate culture showed that cinnamon extract had the most significant inhibitory effect on yeast In the 30 days of experimental observation, the antibacterial circle of cinnamon extract was the largest, and the inhibition circle did not shrink The blank yeast grows all over the culture dish, while the control yeast grows all over the culture dish except inside the inoculation circle, as shown in Figure 2 2.5 investigation on the effective period of Chinese herbal medicine bacteriostasis Clove has a strong inhibitory effect on mold, and it can effectively inhibit the growth and reproduction of mold and shrink the spores in the observation period of 2 months The research trend shows that clove can effectively inhibit the growth of mould for a long time See Table 3 and figure 3 3 Discuss the experiment through the research and comparison of 6 kinds of Chinese herbal extracts with bacteriostatic effect, the clove extract has significant bacteriostatic effect, and has the characteristics of light color, pure fragrance, etc., which is especially suitable for food as a natural preservative Cinnamon extract showed good inhibition effect on yeast strains, but its color was deep and aroma was strong, so it should be used after dilution Clove showed a strong inhibitory effect on mold, and it could effectively inhibit the growth and reproduction of mold and shrink spores in the observation period of 2 months This study aimed at the growth inhibition experiment of the susceptible bacteria in the storage of fruits and vegetables, and provided a theoretical basis for the development of new natural preservatives for fruits and vegetables Its popularization and application will bring huge economic and social benefits.