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The traditional thermal processes are effective on sterilization of milk and extension of shelf life. However, they bring about many adverse effects. For example, they may reduce the valuble nutrients, darken the color, cause the undesirable cooking flavor, and destroy sensitive components, etc. So it is important to develop the application of non-thermal processing technology on the processing of high-quality milk. Pulsed electric fields (PEF) is a promising non-thermal food preservation technique that is suitable for antiseptic effectiveness of any liquid. This technology requires a relatively small investment, low running costs, and it is very fit for large-scale industrialization and continuous production.Compared with the extensive studies on the application of PEF in sterilization, odor and shelf life of juices, there are limited reports about the application of PEF in protein-based and fat-based foods, especially the effects of PEF on composition and quality of these foods. The present study provide the foundation for the application of PEF in fat-based foods and the information and technique literatures for the milk industry. Therefore the research has practical value.In this study,effects of PEF treatment time on inactivation of microbe were investigated. The utmost attractive treatment conditions is 30 kV/cm, 600μs and 200Hz. The results of storage experiment showed that synergistic effect of PEF and low temperature storage made a significant decrease on PEF treated cells, and brought the milk a shelf life about 24 days in 4℃. PEF processing didn’t cause significant changes in physico-chemical properties and mutrition.Volatile compounds from the milk were extracted by solid-phase microextraction (SPME) methods, and identified by the gas chromatography-mass spectrometry. Results showed that the aldehydes, ketones, fatty acids, esters, alcohols and aromatic compounds were the common components. Twenty-eight and thirty-one volatile components were identified in raw milk and PEF-treated milk, respectively. Volatile profiles showed that 2,3-butandione, 2-butanone.3-hydroxy-, benzaldehyde,δ-decalactone, 1-hexadecanol andγ-dodecalactone were disappeared, while ethanal, 2-pentanone, 1-octen-3-one, (Z)-2-heptenal, 1-hexanol, heptanol, 2-furanmethanol, 2(5H)-furanone andδ- dodecalactone were newly formed in PEF-treated milk.The intention of this research was to characterize the aromatic compounds of the two milk as extracted by SPME. In raw milk, nine aroma-active compounds were found, containing butanoic acid, 2,3-butandione, 2-butanone.3-hydroxy-, acetic acid, hexanal, nonanal,δ-decalactone,γ-dodecalactone and a kind of unknown compound. While there were thirteen kinds of aroma-active compounds in PEF-treated milk, containing ethanal, hexanal, butanoic acid, 1-octen-3-one, heptanal, acetic acid, nonanal, decanoic acid, 2(5H)-furanone,δ- dodecalactone, 2-pentanone and two kinds of unknown compounds. The OSME (a Greek word) showed that the raw milk could be described as creamy and compared to creamy/caramel/rancid/grass/metal of the PEF-treated milk.Sensory assessment of the two samples suggested that both were accepted by taste panel. By the side of raw milk, PEF-treated milk have not a rich aromatic odor rather than off-odor.Other researches were concentrated on volatile compounds from the skim milk and cream emulsions by PEF-treated. It was concluded that fats performed an important role in the information of volatile compounds. PEF treatment promotes the formation of aldehydes.
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