Influence Of High Hydrostatic Pressure Processing On Sterilization And Qualities Of Orange Cyst

High hydrostatic pressure (HHP) technology can effectively kill harmful microorganisms infruits and vegetables, ensuring their safety and prolonging their shelf life. More importantly, theirinherent flavor and nutrients are well maintained after HHP processing, meeting the consumers’demands of freshness, nature, safety and health to fruits and vegetables. In this paper, orangesimported from South African were elected as raw materials, while the orange cyst was chosen asHHP processing object to study the influence of processing pressure and time on physicochemicalparameter (such as total acid, total sugar, soluble solid, Vc), microorganism and aroma components.The main results of this paper were summed up as follows:1. HHP processing had little influence on physicochemical parameter such as total acid, totalsugar and soluble solid (P>0.05). With the increasing of processing pressure and processing time,preservation rate of Vc in orange cyst declined slightly (P>0.05), the preservation rate of Vc was92.62%after HHP processing of500MPa for15min, declined by only5.94%when comparedwith the blank sample. The flavor and nutrients in orange cyst which had good edible safety andstorage stability were well maintained after HHP processing.2. HHP processing pressure and time would significantly decline the total number of colony inorange cyst (P<0.05). Increasing processing pressure and processing time could enhancegermicidal efficacy. Logarithm was only1.70after HHP treatment of400MPa for10min, whichhad reached national food hygiene standards of fruits and vegetables juice (GB19297-2003),moreover, germicidal efficacy was well when HHP pressure was greater than or equal to450MPa.Meanwhile, we didn’t detect any bacterium coli, which belonged to gram-negative bacterium andwas extremely sensitive to pressure, so we thought the bacterium coli would be killed completelywhen HHP pressure was less than or equal to300MPa. When the processing pressure was between300and400MPa, increasing processing pressure and time had little influence on heat resistantmoulds, however, the test groups didn’t detect any heat resistant mould when pressure was450MPa and500MPa respectively, which showed that those two pressures had good effect ondestroying heat resistant moulds.3.Analysis of aroma components in orange cyst was carried out byGas-Chromatography-Mass Spectrometry(GC-MS). The results showed that the main flavourcompounds in orange cyst were limonene, fanlun orange vinyl, ginseng squalene, ethyl butyrate,sunflower aldehyde, carvone,linalool and terpineol. The mass fraction of limonene reached 62.68%, which was the main flavour components in orange cyst. HHP treatment had significantlychanged the flavour compounds, the relative contents of alcohols in orange cyst slightly decreasedwhile the numbers and species of alkenes and esters decreased obviously. Results showed that thecontents of limonene dramatically decreased by89.8%after HHP processing of500MPa for5min.However, the numbers and species of aldehydes and ketones both increased with the contents ofcarvone increasing by13times after HHP processing of300MPa for15min. These all related tothe increasing of temperature caused by the effects of HHP. Therefore, the qualities and flavor oforange cyst were well kept after HHP processing of400MPa for10min, as well as sterilizationeffects.