Changes in chemical quality indices during long‐term storage of palm‐olein oil under heated storage and transport‐type conditions

Abstract

Six quality indices, namely free fatty acids (FFA), peroxide value (PV), anisidine value (AV), oxidative stability index (OSI), total tocopherols and headspace volatiles (hexanal, t-2-hexenal and t,t-2,4-decadienal), were evaluated in a long-term storage trial of 52 weeks at 50 • C of palm-olein, a monounsaturated oil. Three concentrations of copper (0.035, 0.17 and 0.69 mg kg −1 ) were added. FFA values for all the sample treatments increased slightly over the storage period but remained within acceptable limits. PV of the copper-containing samples declined initially and then remained stable up to week 40, after which it increased slightly for the 0.035 and 0.17 mg kg −1 samples. However, PV of the control (no added copper) increased steadily to above the acceptable limit. AV of the copper-containing samples increased much more than that of the control. OSI and total tocopherol values of the coppercontaining samples were markedly lower than those of the control. t-2-Hexenal did not increase during the storage period, whereas hexanal increased in the copper-containing samples but at a slower rate than in the control. Conversely, the copper-containing samples had high levels of t,t-2,4-decadienal but the control had none. AV, OSI and total tocopherols are the most valuable quality indices for assessing monounsaturated oil quality, whereas FFA, PV and headspace volatiles can be misleading.

Monitoring of 2,4‐decadienal in oils and fats used for frying in restaurants in Athens, Greece

“…The latter strengthens the position that the quality of the frying oils is of major importance for the quality of the consumed food. Quantification has been reported for the following cases, without including frying oils: after storage of sunflower oil for 12 wk at 50 7C, a quantity of 2.4 mg/kg 2,4-decadienal was detected [15]; after storage of palm olein oil for 50 wk at 50 7C in the presence of copper, the trans,trans-2,4-decadienal concentration reached approximately 80 mg/kg [16]. Also, after heating trilinolein for 12 h and 24 h, the trans,trans-2,4-decadienal concentration reached 1138 mg/kg, and trans,cis-2,4-decadienal was found at 322.5 mg/kg [17].…”

Effect of microencapsulation and spray drying on oxidative stability of flaxseed oil and its release behavior under simulated gastrointestinal conditions

“…In the present study, experimental results clearly showed that microencapsulation of flaxseed oil by WPC-80 and sodium caseinate provided the oxidative protection for at least 6 months. It can also be concluded that there was a significant effect of storage temperature on the TBA value of MFOP preparations.P-Anisidine Value (P-AV)p-anisidine value (AV) is a reliable indicator of oxidative rancidity of fats and oils(45). It indicates the content of volatile and unsaturated aldehydes (majorly 2-alkenals and 2, 4-alkadienals) generated as secondary oxidation products during decomposition of hydroperoxides(46).…”

Long-term storage of three unconventional oils

“…Public reaction usually occurs only when rancid or oily flavors lower the quality of food purchased. Different authors studied the changes in fatty acid and tocopherol composition, stability, effect of packaging materials and chemical quality indexes of oils during storage (Fourie and Basson, 1989;Gómez-Alonso et al, 2004;Evans et al, 1973;Okogeri and Margari, 2002;Van der Merwe et al, 2003;Budin and Breene, 1993;Gutierrez and Fernanz, 2002) Especially in countries with high temperatures and limited facilities for cool storage the oxidative deterioration of fats and oils is a great problem. In this case the availability of fats and oils with a high oxidative stability during long term storage under the extreme climatic conditions of these countries is important.…”