Effects Of Processing Technology On Quality Of Carrot Puree

Carrot is one of the main vegetable varieties in china, and has rich nutrition. Carrot pureeis one of major carrot processed and export products, but the lower quality has influenced onexported trade to our country. In-depth study of the processing technical factors, which affectthe carrot puree quality, has theoretical and practical significance on improving the technicallevel and product quality, promoting carrot puree process industry and technologydevelopment. Main carrot cultivars were taken as raw material in this paper, and effects ofcarrot varieties, blanching treatments, enzymatic treatments, sterilization treatments andstorage conditions on the quality of carrot puree were investigated. The main results andconclusions were as follows.1. Changes of different varieties of carrot puree on quality during storage. The resultsshowed that there were differences between sensory and physico-chemical indexes of fivecarrot varieties. Titratable acid content, total sugar content, soluble solids content andcarotenoid content were determined. The higher contents of varieties were Japan mountain redand eastern six-inch carrot. Chromaticity a b values had the similar trend with carotenoid. Thered carrot puree and eastern six-inch carrot puree had higher sensory evaluation scores.Eastern six-inch carrot was the suitable variety for processing carrot puree.2. Effects of processing technology on β-carotene content of carrot puree. The β-caroteneof carrot puree was extracted by petroleum ether and determined by high performance liquidchromatography, and suitable extraction parameters of β-carotene were obtained, includingextracting3times, extracting temperature of50℃, extracting time of80min. Hot waterblanching, steam blanching, vitamin C blanching and citric acid blanching treatments on thecontent of β-carotene in carrot puree were studied. The result showed that citric acidblanching was the best blanching method, and the best citric acid blanching conditions wereobtained, including citric acid mass fraction of1.4%(m/m), blanching time of18min,blanching temperature of84℃, then the mass fraction of β-carotene reached23.59mg/kg.Variance analysis of response surface regression model showed that blanching temperature,blanching time and mass fraction of citric acid were three important factors that affectβ-carotene content, in the order of temperature, time, and mass fraction of citric acid.Cellulase enzymatic parameters were optimized, including cellulase mass fraction of0.5%(m/m), pH value4.0, enzymatic time of150min, and enzymatic temperature of55℃.Pectinase enzymatic parameters were optimized, including pectinase mass fraction of0.1%(m/m), pH value3.5, enzymatic time of120min, and enzymatic temperature of45℃. High quality of carrot puree were gotten after pectinase enzymatic test (pectinase mass fraction of0.1%(m/m), pH value3.5, enzymatic time of90min, enzymatic temperature of45℃) andcellulase enzymatic test (cellulase mass fraction of0.3%(m/m), pH value4.0, enzymatic timeof120min, enzymatic temperature of50℃), that was the best enzymatic method.High-pressure sterilization of121℃for5min, boiling water sterilization for20min and hotwater sterilization of85℃for30mintreatments on β-carotene content of carrot puree wereinvestigated. The result showed that hot water sterilization of85℃for30min was the beststerilization method.3. Effects of storage conditions on β-carotene content of carrot puree. Three differentstorage temperatures (0℃、5℃、20℃) and four different storage pH values (2.5、3.5、4.5、5.5) that effects on β-carotene content of carrot puree were studied. The best storageconditions were obtained, including storage temperature of0℃, storage pH value of3.5.