Storage Characteristics And Preservation Methods Of Guava Fruits

Guava (Psidium guajava Linn.), is a kind of nutritious and popular tropical fruits. Butthe postharvest qualities of guava fruits are easy changed, such as hardness, flavor andnutrients fall rapidly, which lead to be unsuitable to storage and transport, short shelf-life,and decreased value. Therefore, it is significant to research on postharvest physiologychange of guava fruits, and related fresh-keeping method. In this paper, we studied thestorage characteristics and preservation methods of the whole and fresh cut guava fruits.The specific contents and results are as follows:1. Study on the storage characteristics of guava fruits. Analysis the postharvestphysiology of guava whole fruit by investigation of its appearance quality, nutrient qualityand activities of browning related enzymes during the storage period15d at8℃and20℃, respectively. The results showed that low temperature (8℃) effectively reduced theloss of vitamin C (Vc) and soluble sugar, inhibited the activity of POD, slowed down theincrease of the respiration rate and acidity, and maintained the color of guava fruits. Thenthe correlation analysis showed that the decline of the soluble protein and soluble sugar inthe early stage were correlated with the increase of the original pectin, soluble pectin andtotal acid under8℃. While the decline of original pectin and soluble sugar werecorrelated with the rising of soluble pectin, soluble protein and total acid under20℃.Thus under different storage temperatures, the nutritional and physiological qualities ofguava fruits were also diverse.2. Study on the effect of the different packing ways on the quality of fresh cut guava.Glutathione (GSH) combined with different packing methods (BOPP film cassette gaspackaging, PO film bag packaging with PE cling film) was researched at20℃. Theresults showed that, the decomposition rate of Vc, soluble protein content of fresh cutguava decreased, the quality of the color improved by using BOPP film cassette packaging,but the effect of PO and PE film not obvious. High oxygen (50%O2+30%CO2+30%N2)MAP could effectively restrain the anaerobic respiration, inhibit the activity of POD andrespiratory intensity, as well as flesh browning degree declined. And in all GSH treatments,the hardness and Vc decreased, but the degree of decomposition of soluble protein andbrowning declined. So BOPP film should be developed. MAP could improve the quality of fresh-cut guava. And GSH as an antioxidant also can inhibit browning and prolong theshelf-life.3. Study on the influence of different preservation methods on the quality of guavafruits. The effects of sodium hypochlorite disinfectant, MAP and hot water treatment onphysiological and quality changes of whole guava fruitswere investigated at8℃and20℃.The results showed that compared to the control, the treatment groups effectivelysuppressed the decomposition of Vc, soluble sugars and organic acids, improved thedecline of their sensory quality. At low temperature (8℃), hot water, combined withsodium hypochlorite disinfection and MAP (50%O2+50%N2) inhibited the respirationrate and the formation of malondialdehyde (MDA), decreased browning and decline ofhardness. While at20℃, hot water and disinfectant treatment only restrained thegeneration of MDA significantly, and not on other index,and not MAP. These resultsconcluded that low temperature storage, hot water and hypochlorite disinfection combinedwith MAP could obvious improve the quality of guava fruits.In conclusion, the effective preservation methods of guava fruits are low temperaturestorage, BOPP film cassette packaging, HOAP, hot water and disinfection treatment,which can prolong their shelf-life. This study provides methods and scientific basis for thepreservation technology of guava and other fruits and vegetables.