Development of a new preservative for postharvest

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Development of a new preservative for postharvest fruit storage of sweet orange (Part 1)

sweet orange is not only nutritious and has good taste and flavor, but also one of the important bulk fruits suitable for processing and fresh eating. However, the ripening period of sweet orange fruit is relatively short, and most fruits need to be preserved for a long time after harvest, so as to avoid a large number of rotten fruits and quality deterioration during storage, resulting in serious economic losses

Carbendazim and tobuzzin 2,4-D have played an important role in the development of fruit production and the enrichment of people's lives as fruit preservatives for decades, and have made efforts to improve total factor productivity. However, with the development of science and technology and the continuous improvement of people's living standards, the food pollution caused by chemical fungicides and the adverse effects on human health have already attracted great attention of the world. It is true that many scholars in the world have reported a large number of studies on the green preservative of fruits after harvest, and have made many achievements, such as the use of antibiotics produced by Bacillus subtilis to control peach brown rot caused by Alternaria alternata, with excellent results, etc., but most of them are still immature and difficult to be widely used commercially. It can be considered that chemical agents with high efficiency, low toxicity and low residue will still be used as fruit postharvest preservatives for a long time in the future. This universal machine has the following characteristics: effective agents. In view of this, the author has developed a new preservative suitable for postharvest room temperature storage of sweet orange after repeated tests and screening in recent years

L materials and methods

1.1 components of the preservative tested

there are several differences in the screw rod of the electronic tensile testing machine. In which test, 95% tekto raw powder with high efficiency, broad spectrum and low toxicity is used as the bactericide during fruit storage, p-chlorophenoxyacetic acid is used as the respiratory regulator, and sodium bicarbonate, carboxymethyl cellulose, sodium EDTA and other auxiliary factors are used to test and screen new preservatives for sweet orange storage. Carbendazim +2,4-d and ab preservatives were used as control agents in the test, and blank control (CK) without any treatment was set

1.2 test fruit

from 2000 to 2002, the fruit of Jincheng, a sweet orange variety with more than 20 years of age, was picked from Jiangjin city, Chongqing in the first ten days of December every year. After picking out the fruit damaged by diseases and pests and with obvious mechanical wounds, the fruit with a diameter of about 70mm was selected as the test fruit

1.3 treatment method

for the preparation of the test solution, it is appropriate to fully stir tektol and sodium bicarbonate with a small amount of warm water at about 80~c until there are no particles, and then add carboxymethyl cellulose, sodium EDTA and the rest of the water to mix well. Soak the tested fruit in the solution for about 2 minutes, take it out of a cool place and dry it. After 5 days of pre storage, the single fruit is wrapped in polyethylene fruit preservation bags, and then placed in the fruit box. During the preliminary screening test, 3O fruits were used for each treatment and repeated for 3 times. In the optimization test of preservative components, 100

fruits were used for each treatment and repeated for 4 times

l.4 storage period management and result observation and analysis

the experimental fruits are stored at room temperature in the ventilated fruit storage warehouse, with a daily average temperature of 7-17 ℃ (varying due to the temperature), and the humidity is controlled at about 85%. In the experiment, rotten fruits, oil spot diseased fruits, green seeded fruits and dry seeded fruits were observed and recorded once a month, and rotten fruits were removed at the same time. Any disease spot on the surface of the fruit that is obviously damaged by fruit rot pathogens, regardless of the size, is recorded as rotten fruit, and the rotten fruit caused by different pathogens are recorded separately. When there are two kinds of fruit rot fungi on the same rotten fruit, only the fruit rot type with relatively large disease spot area is recorded, and the respiratory intensity and weight loss of the fruit are measured once a month. At the beginning and end of the experiment, the main physical and chemical indexes of the tested fruit were measured respectively

2 results and analysis

2.1 Xintian is not only an improvement on rubber materials. The components and concentration of orange preservative (hereinafter referred to as new preservative) are shown in Table 1 after repeated tests and screening over the past few years

the rotten fruit rate of sweet fruit treated with this preservative stored at room temperature for 4 months is equivalent to that of carbendazim +2, 4-D, which is still widely used in current production, while the dry fruit rate and oil spot fruit rate are significantly lower than all controls

2.2 preservative and fresh-keeping effect of the new preservative

2.2, 1 preservative effect

the rotten fruit rate of sweet orange fruit treated with the newly developed preservative for 4 months is 3.8%, which is not significantly different from ab preservative, is significantly different from carbendazim +2, 4-D, and is extremely significant from the blank control of 26.54% rotten fruit. It shows that the preservative effect of the new preservative used for postharvest storage of sweet orange is equivalent to or better than carbendazim +2,4-d, which has been used for decades and has a good effect. It can be confirmed that it has an inhibitory effect on fruit rot fungi, as shown in Table 2

test time (year, month) new preservative AB preservative carbendazim +2, 4-D CK although the rate of rotten fruit when stored for 4 months is still very low, it should not be more than 4 months in terms of room temperature storage, otherwise it will lead to excessive consumption of respiratory and metabolic nutrients for a long time and obvious increase in ethanol content, resulting in a decline in quality and poor merchantability of stored fruits

2.2.2 inhibition effect on oil spot

when the preservative developed in the test treated the fruit for 4 months, the fruit rate of oil spot disease was only 3.0%, which was 13% and 15% lower than that of the AB preservative and carbendazim +2, 4-D treatment, and 22% lower than that of the blank control, which significantly showed that the fruit rate of oil spot disease in the new preservative treatment was significantly different from that of all other control treatments, as shown in Table 3

although the oil spot disease of Citrus during storage does not directly cause fruit decay, the occurrence of oil spot disease will deteriorate the quality, and the pulp often has peculiar smell, which will significantly reduce the merchantability of the fruit. In addition, the ability of peel to resist pathogen infection is significantly reduced after the occurrence of fruit oil spot disease, especially in the high temperature environment, the pathogen is easy to invade from the disease spot of oil spot disease, resulting in fruit decay

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