Study On Mechanism Of Keeping 'Fuji' Apple Hardness By Hypobaric Storage

This test selected apple as raw material, temperature, relative humidity and pressure as variables to do orthogonal test.Select the smallest processing time of hardness of fruits with the storage time as the apple best hypobaric storage conditions.The results showed that: apple can be best hypobaric stored when the condition is that -1℃temperature, 95% relative humidity, vacuum pressure of 80KPa.The store apple in the best conditions of hypobaric storage and analyzed the relevance between the change of indicators and the flesh firmness. The results showed that: Hypobaric storage can delay the degree of fruit softening. In the storage process, the content of O-2 and H2O2 in apple pulp continually increased, in the pre-storage, active oxygen little changed, but in the late , accumulation became obvious, the effect of membranaceous peroxide increased, the damage of cell membrane aggravated, and these caused accumulation of malonaldehyde(MDA) and addition of relative conductivity. Subatmospheric pressure storage is in favor of reducing the Content of superoxide anion in the pulp, and restrain the content of Hydrogen peroxide,it also can reduce the extent of peroxidation membranaceous.Apple is a typical respiratory variability fruit, ethylene peak appeared at 15s day in the process of storage under non-decompression. The peaks of activity of PG andβ-Gal all appeared at 25s day under non- decompression.Under the condition of decompression, tiny ethylene peak. In the the process of storage under decompression, ethylene was less than that under non-decompression.The peaks of activity of PG andβ-Gal appeared respectively at 20 days and 25 days under decompression, and activity of PG andβ-Gal were less than those under non-decompression in the same process of storage.With the accumulation of PG andβ-Gal,the storage period extened, protopectin gradually breaked up into Water-soluble pectin,cell relaxed, and the firmness of fruit also decreased. The activity of PG andβ-Gal were restrained under condition of decompression, and it prevented original pectin from hydrolyzing and it was propitious to retain hardness of apples.