The fatty acid composition as well as the antioxidant composition and content of two commercially available chia oils of different origins were studied. The purpose of this work was the study of the oxidative stabilit...The fatty acid composition as well as the antioxidant composition and content of two commercially available chia oils of different origins were studied. The purpose of this work was the study of the oxidative stability from different methods and the antioxidant content of the chia oils compared with other commercial oils. The oxidative stability of the oils was determined based on the oxidative stability index test （OSI test） conducted at 110 ~C and isothermal as well as non-isothermal differential scanning calorimeter （non-isothermal DSC） for the chia oil and the linseed oil. The OSI induction time of chia oil was compared with that of commercially available linseed, canola, sunflower and high-oleic sunflower oils, chia oil being the least stable oil among those studied. The inherent stability value and oxidazibility for linseed oil was lower than the chia oil A may be ascribed to a lower linolenic acid content of the former. The induction time （It） quotient at 110 ~C calculated for chia oil A and linseed oil were similar, suggesting a high degree of consistency between the results obtained by the two methods. The activation energy and specific reaction rate constant of chia and linseed oils were compared based on the results of isothermal and non-isothermal DSC. An apparent inconsistency in the experimental data results from the temperature-dependence of the activation energy of each fatty acid which can explain because the methods conditions were different.展开更多
The purpose of this work was to study the thermal characterization of oils extracted from native seeds and fruits of the Argentina, Uruguayan region. This is important because it＇s necessary to find new applications ...The purpose of this work was to study the thermal characterization of oils extracted from native seeds and fruits of the Argentina, Uruguayan region. This is important because it＇s necessary to find new applications for food industry. Uruguayan wild cardoon seed, Argentinian wild papaya seeds, Argentinian avocado pulp, Argentinian cherimoya seeds, Argentinian grapeseeds and four commercial brands of chia oils were studied. The thermal behaviors of the oils were analyzed on a differential scanning calorimetry （DSC）, TA Instrument, Q20 model equipped with an intercooler. These oils＇ thermal profiles presented differences, which are related to the compositions of fatty acids and triacylglycerols. The thermogram for the chia oil, with a high content of linolenic acid, presented a very important peak at about -40 ℃; whereas, the papaya oil with an oleic acid content of 74%, showed a peak at about -3 ℃. When comparing the thermal behaviors of these oils to commercial brand oils, it was found that the chia oil is similar to the flaxseed oil, the papaya similar to the olive oil and the avocado similar to the rice bran oil. The avocado oil, in particular, presents high solid content at cold store or winter temperatures, which would make its use in those conditions difficult （for example, a cosmetic cream or gourmet oil）. In conclusion, the thermal behavior of one oil sample as determined by DSC provides valuable information with regards to the possible use of new oils of American origin as replacement of usual commercial others.展开更多
文摘The fatty acid composition as well as the antioxidant composition and content of two commercially available chia oils of different origins were studied. The purpose of this work was the study of the oxidative stability from different methods and the antioxidant content of the chia oils compared with other commercial oils. The oxidative stability of the oils was determined based on the oxidative stability index test （OSI test） conducted at 110 ~C and isothermal as well as non-isothermal differential scanning calorimeter （non-isothermal DSC） for the chia oil and the linseed oil. The OSI induction time of chia oil was compared with that of commercially available linseed, canola, sunflower and high-oleic sunflower oils, chia oil being the least stable oil among those studied. The inherent stability value and oxidazibility for linseed oil was lower than the chia oil A may be ascribed to a lower linolenic acid content of the former. The induction time （It） quotient at 110 ~C calculated for chia oil A and linseed oil were similar, suggesting a high degree of consistency between the results obtained by the two methods. The activation energy and specific reaction rate constant of chia and linseed oils were compared based on the results of isothermal and non-isothermal DSC. An apparent inconsistency in the experimental data results from the temperature-dependence of the activation energy of each fatty acid which can explain because the methods conditions were different.
文摘The purpose of this work was to study the thermal characterization of oils extracted from native seeds and fruits of the Argentina, Uruguayan region. This is important because it＇s necessary to find new applications for food industry. Uruguayan wild cardoon seed, Argentinian wild papaya seeds, Argentinian avocado pulp, Argentinian cherimoya seeds, Argentinian grapeseeds and four commercial brands of chia oils were studied. The thermal behaviors of the oils were analyzed on a differential scanning calorimetry （DSC）, TA Instrument, Q20 model equipped with an intercooler. These oils＇ thermal profiles presented differences, which are related to the compositions of fatty acids and triacylglycerols. The thermogram for the chia oil, with a high content of linolenic acid, presented a very important peak at about -40 ℃; whereas, the papaya oil with an oleic acid content of 74%, showed a peak at about -3 ℃. When comparing the thermal behaviors of these oils to commercial brand oils, it was found that the chia oil is similar to the flaxseed oil, the papaya similar to the olive oil and the avocado similar to the rice bran oil. The avocado oil, in particular, presents high solid content at cold store or winter temperatures, which would make its use in those conditions difficult （for example, a cosmetic cream or gourmet oil）. In conclusion, the thermal behavior of one oil sample as determined by DSC provides valuable information with regards to the possible use of new oils of American origin as replacement of usual commercial others.
