Study On Key Technologies Of High-Pulp Lime Juice

Citrus peel which has abundant physiologically-active compounds such asflavonoids, vitamin C, pectin and carotenoid and so on, is the by-product of orangeprocessing. Comprehensive utilization with citrus peel are advantageous for increasingeconomic benefit, decreasing pollution and protecting environment. Distilling technologyof essential oils, pectin, dietary fiber, flavonoids were reported domestic and abroad.Mass manufactory aimed at distilling the single composition of citrus peel in our country,which causing the resources wasted and the circumstance quadratic pollution. Citrus peelcontaining physiological substances that maked itself have the function such asantioxidant activity and anticancer. Taking citrus peel as material, using high and newtechnology, citrus peel was produced into flavourful and functional beverage, while thenutriment and flavor component was preserved farthest, which is the developing trend forcomprehensive utilization with citrus peel.The processing technology of high-pulp lime juice was taken as the pivotal problemin the paper; Debittering, texture, flavor and rheological property were studied, whichprovided the theoretical reference to processing technology, facility selection and sensoryevaluation. These main results were indicated as follows:1 Debittering of lime juice was studied by resin adsorption. The rates of adsorptionand desorption for naringin and limonins by macroporous resin were higher than byion-exchange resin. Static kinetic, dynamic kinetic and the preserving rate of nutrimentwere studied, the results showed the sequence of equilibrium time for absorbing naringinwas R2＞R4=R6, As while the sequence of equilibrium time for absorbing limonins wasR4＞R2＞R6, The nonleakage volume were 16BV,18BV respectively when R6 dynamicadsorption for naringin and limonins. The premise that the content of limonins is fewerthan limen, the adsorption capacity for naringin and limonins were 62.454mg/mL and0.504mg/mL respectively. These macroporous resin were able to reduce acidity of limejuice, which improved quality of lime juice. R6 had no effect on nutritional component,but R2 and R4 had an effect on nutritional component. In conclusion, the capability ofdebittering by R6 was better than by R2 and R4. R6 was taken as the preferredmacroporous resin.2 The textural characteristics of freezing lime slice with different pretreatment (roomtemperature, unsettled freezing, 1%Ca²⁺ immersed f freezing, 1:1 sugared) were studied, the results showed that the downtrend of crispness of lime slice with1:1 sugared is theleast during freezing. The osmosis and protection of sugar can lighten damage to cell andmaintain cell turgor. PG activity was restrained by low temperature simultaneity. PGactivity in Lime slice in room temperature is greater, so that protopectin was hydrolyzedinto solubility pectin which maked it crispless. Unsettled lime slice suffered from icecrystal during freezing, which might produce a loss of crispness. The effect of calcium ison the maintenance of cell wall structure by its interaction with pectic acid in the cell wallto form calcium pectate. Lime slice with 1% Ca²⁺ immersed boosted up the ability ofwater-holding and maintained crispness. SEM images showed an advanced state ofplasmolysis or shrinkage of the cells and the microstructure worse and worse wereobserved in the lime slice in room temperature. The appearance presented softening andsubsiding in unsettled lime slice with freezing. The interaction structure was observsed inthe lime slice with 1%Ca²⁺ immersed, the lime slice with 1:1 sugared had the compactmeshwork and maintainved cell turgor. Therefore, the damage to fruit and vegetable werebated and restrained and the texture was maintained preferably by the means of Ca²⁺immersing and sugaring before freezing.3 The flavor componentsof high-pulp lime juice fore-and-aft thermal sterilization wasstudied using solid phase micro-extraction and Gas Chromatography-Mass Spectrometry.A total of 51 components were identified in the high-pulp lime juice before thermalsterilization, while 28 components were olefin, 13 components were alcohols, 5components were aldehydes, 3 components were esters, 2 components were ketones. Themore comparative contents 14 flavor component were Limonene,γ-Terpinene,β-Myrcene,(Z)-beta-Ocimene, Isoterpinene, Linalool, a-Terpineol, 1-Octanol, Citronellol,Terpinen-4-ol, Nerol, Decanal, Geranial, Geranyl acetate. A total of 51 components wereidentified by thermal sterilization 85℃, 15min, A total of 44 components were identifiedby thermal sterilization 100℃, 5min, the higher the temperature, the more effect on theflavor components. Thermal sterilization reduced the comparative contents of olefin andketones, while increased the comparative contents of alcohols, aldehydes and esters.Thermal sterilization which damaged primary flavor components caused chemicalreaction happened, and it was disadvantage for the peculiar flavor components inhigh-pulp lime juice.4 Rheological property of high-pulp lime juice was studied by the rheometerAR500. The results showed that high-pulp lime juice was pseudoplastic fluid. By regression analysis, within the range of temperature and concentration studied. The effectof temperature on viscosity could be described by an Arrhenius type equation, The effectof concentration on viscosity could be described by an Index type equation, the combinedeffects of temperature and concentration on the viscosity of high-pulp lime juice candescribed by an equationη=2.8616×10^-7(4.302/T+0.1407C).