Headspace solid phase microextraction chromatography （HS-SPME/GC） was evaluated as a tool in determining the rate of oxidation in oxidized soybean oil samples by measuring the production of hexanal as a secondary ma...Headspace solid phase microextraction chromatography （HS-SPME/GC） was evaluated as a tool in determining the rate of oxidation in oxidized soybean oil samples by measuring the production of hexanal as a secondary major volatile breakdown product of linoleic acid. Samples of the headspace taken from sealed 20 mL vials, incubated 30 min at 50 ~C followed by 5 min adsorption, were injected into a gas chromatograph with 2 min thermal desorption. In applying SPME, different analytical conditions were evaluated. The linearity of response of the volatiles for the HS-SPME/GC procedure using a carboxen-polydimethylsiloxane fiber was determined from 3 g of mineral oil spiked with a hexanal standard solution at different levels. Using the optimized extraction conditions, an R value close to unity （R = 0.999） was found, and the repeatability （n = 1 l） was 6.31%. The results indicated that hexanal is linearly related to peroxide value （PV） only intermediate PV ranges （10-18 meq/kg）. The study also showed that HS-SPME/GC procedure was a simple and reproducible method for the analysis of hexanal in the HS of commercial soybean oil samples, and is useful as a quality control and research tool for the evaluation of flavor quality and shelf life of vegetable oils.展开更多
Ultraviolet （UV） irradiation is proven to be an effective method to reduce aflatoxin in peanut oil, but the changes of peanut oil quality are not clear, especially in storage life. In this study, impacts of UV irr...Ultraviolet （UV） irradiation is proven to be an effective method to reduce aflatoxin in peanut oil, but the changes of peanut oil quality are not clear, especially in storage life. In this study, impacts of UV irradiation treatment on quality of peanut oil were investigated. Acid value, iodine value, oxidative stability and total phenol content that refer to rancidity and oxidation of oil were estimated under 365 nm UV irradiation processing and during different storage time. Results indicated that acid value was increased slightly under irradi-ation and in storage life while iodine value, total phenol content and oxidative stability de-clined weakly. Changes of these quality indexes were all within safe and acceptable levels. It can be confirmed by this study that UV irradiation is a safe strategy for AFB1 detoxification in peanut oil and not influence upon quality and stability of peanut oil.展开更多
文摘Headspace solid phase microextraction chromatography （HS-SPME/GC） was evaluated as a tool in determining the rate of oxidation in oxidized soybean oil samples by measuring the production of hexanal as a secondary major volatile breakdown product of linoleic acid. Samples of the headspace taken from sealed 20 mL vials, incubated 30 min at 50 ~C followed by 5 min adsorption, were injected into a gas chromatograph with 2 min thermal desorption. In applying SPME, different analytical conditions were evaluated. The linearity of response of the volatiles for the HS-SPME/GC procedure using a carboxen-polydimethylsiloxane fiber was determined from 3 g of mineral oil spiked with a hexanal standard solution at different levels. Using the optimized extraction conditions, an R value close to unity （R = 0.999） was found, and the repeatability （n = 1 l） was 6.31%. The results indicated that hexanal is linearly related to peroxide value （PV） only intermediate PV ranges （10-18 meq/kg）. The study also showed that HS-SPME/GC procedure was a simple and reproducible method for the analysis of hexanal in the HS of commercial soybean oil samples, and is useful as a quality control and research tool for the evaluation of flavor quality and shelf life of vegetable oils.
基金This work was supported by the Natural Science Foundation o f China （31401601）, National Key Project for Agro-product Quality ＆ Safety Risk Assessment, PRC （GJFP2015007）, Special Fund for Grain-scientif-ic Research in the Public Interest （201513006-02）.
文摘Ultraviolet （UV） irradiation is proven to be an effective method to reduce aflatoxin in peanut oil, but the changes of peanut oil quality are not clear, especially in storage life. In this study, impacts of UV irradiation treatment on quality of peanut oil were investigated. Acid value, iodine value, oxidative stability and total phenol content that refer to rancidity and oxidation of oil were estimated under 365 nm UV irradiation processing and during different storage time. Results indicated that acid value was increased slightly under irradi-ation and in storage life while iodine value, total phenol content and oxidative stability de-clined weakly. Changes of these quality indexes were all within safe and acceptable levels. It can be confirmed by this study that UV irradiation is a safe strategy for AFB1 detoxification in peanut oil and not influence upon quality and stability of peanut oil.
