Study On Vegetable Preservation By Pretreatment With Pressurized Inert Gases

Fruits and vegetables were main agricultural products except for grain;the output of fruits andvegetables in China was very large. Despite the rapid development of fruits and vegetables producingin last 20 years, the technology of fruits and vegetables preservation was limited. There were manyresearches in fruits and vegetables preservation, which focused on the new preservation technology.The objective of this research was to exploit new preservation technology by clathrate hydrates.The main studies on clathrate hydrates were about nature gas hydrates. There were reports onconcentration of liquid foods by the use of gas hydrate. Xenon is one of inert gas that could formclathrate hydrate crystal. The formation condition of xenon hydrates and effect of xenon hydrate onwater viscosity was studied. The tissue changes of fruits and vegetables were observed under xenontreatment. The paper studied the effects of single xenon on the preservation of cucumber and asparagus.The POD and PPO activity of cucumber were measured in different xenon pressure, treat time andtemperature. At last, the preservation conditions of clathrate hydrates were summarized. Thepreservation of asparagus by 0.3MPa xenon pressure treated for 24h was studied. The weight loss,blossom rate, respiration rate, vitamin C and cellulose of asparagus were examined and analyzed.The physiological and physical properties of asparagus were studied after treated by mixtures ofargon and xenon, rate is 7:2. It showed that asparagus treated by mixtures of argon and xenon for 24 hcould be storied for 20 days. The preservation method reduced the blossom and weight loss ofasparagus, and delayed the climacteric peak, it also showed that, the method could slow down thecellulose increase, lessen the vitamin C and chlorophyll loses. Asparagus was treated by mixture ofCO2 and xenon, the rate was 1:1. The chlorophyll, CAT, protein contain, SOD and active oxygen wasstudied.