Strawberry irradiation preservation technology

Strawberry is a perennial berry, contains high vitamin C, is a high-grade fruit. However, the short supply period is difficult to preserve. The method of storage for a long time is low-temperature, temperature-freezing, and the temperature is -18°C. However, after thawing, the fruit is collapsing and effluent, and the flavor of the fresh fruit has been lost, affecting the quality of the product.

In foreign countries, cobalt 60 radiation technology has been used for strawberry preservation for many years. In 1976, the Dutch FAO/IAEA/WHO Expert Committee had recommended that strawberries be irradiated for a dose of 1-3 kGy. In 1992, the irradiated strawberries entered the US market. Research and application in this area are less developed in China. In order to promote the commercialization of radiation and preservation of strawberry and formulate a standardized process, we conducted experiments on the irradiation dose of radiation and the effects of irradiation on the microorganisms and nutrient components.

First, materials and methods

1. Experimental materials: Strawberry fruits were collected from strawberry experimental greenhouses of Zhenjiang Institute of Agricultural Sciences, Jiangsu Province. Variety: Mingbao, 80% maturity, no lesions, no distortion, pale red color, uniform fruit size. The polyethylene boxes were arranged in a single layer and the control group (non-irradiated) and the irradiation group were set up with 6 replicates.

2. Irradiation and storage In the small cobalt chamber of the Institute of Atomic Energy, Jiangsu Academy of Agricultural Sciences, the irradiation time was 4 hours, and the entire time was reversed in half the time. The absorbed dose (kGy) was 1.0, 2.0, and 3.0. The absorbed dose was measured with a ferrous sulfate dosimeter. Immediately after harvesting, irradiation treatment was performed. Immediately after treatment, it was placed in a refrigerator and refrigerated at 4°C.

Second, the results

1. When refrigerated at 4°C, the decay index gradually decreased with the increase of irradiation dose. Compared with the control, 1kGy irradiation reduced decay index by 23.9% within 15 days, decreased by 65.9% after 2kGy irradiation, and decreased by 68.2% after 3kGy irradiation. %. The 2kGy and 3kGy irradiation not only rot little for 15 days, but also has no change in color, hardness, and mouthfeel. Therefore, the irradiation of 2kGy and 3kGy in strawberry can significantly improve the preservation effect.

After strawberry was irradiated by cobalt 60 rays 2.0 and 3.0kGy, the microorganisms on strawberry were partially killed, and the initial total number of microorganisms was reduced. Low temperature (4°C) refrigeration also inhibited the growth of microorganisms on strawberry, thus the strawberry's rotting rate was greatly increased. reduce. The experiment also showed that: Irradiation had no significant effect on the vitamin C and amino acid content of strawberries. Some strawberries were cultivated using human and animal husbandry, and 3.0 kGy rays were used to irradiate strawberry fruits, which could eliminate the contamination of pathogenic bacteria such as E. coli and Salmonella.