Rosemary plant (Rosmarinus officinalis L.), solvent extract and essential oil can be used to extend the usage life of hazelnut oil during deep frying

Abstract

In this study, the effects of rosemary (Rosmarinus officinalis L.) plant (RP), its alcoholic extracts (REE and RME) and essential oil (REO) on the oxidative stability of hazelnut oil (HO) during deep frying were investigated. HOs containing rosemary additives had lower conjugated diene (CD) content, p-anisidine value (AV) and polar material content compared to control values. Additionally, changes in L*, a*, and b* color values and viscosity were lower than control values. RP (50 g/kg) caused the highest retention of a-tocopherol. At the end of the frying period, the induction periods (IPs) of HOs containing rosemary additives were between 9.43 and 35.01 min, much higher than the control IP (4.28 min). The ratios of C18:1/C16:0 and C18:2/C16:0 were 7.6 and 1.2, respectively, in HOs containing 50 g/kg RP, values which were higher than those of the control. The study indicated that HO containing 50 g/kg RP had the best frying performance. Rosemary additives had no adverse effects on sensory acceptability according to results of a sensorial analysis of French fries. The rosemary additives also had no significant effect in terms of texture and color of French fries (P > 0.05). Consequently, this study shows that rosemary plant or extracts can be used to extend the usage life of hazelnut oil for frying.Practical applications: Rosemary is an herb with a high antioxidant activity due to its phenolic compound content. After grinding, it can be directly added to frying oils or added as a solvent extract. In direct application, which does not require the use of any additional chemicals, it increases the stability of the frying oil when it is used in an appropriate amount.

Thermal Oxidation Kinetics of Refined Hazelnut Oil

“…Fatty acid composition of the hazelnut oil was in agreement with those of previous studies (Alasalvar et al, ; Alasalvar, Shahidi, Ohshima, et al, ; Karabulut et al, ), while the concentrations of the total tocopherols were found to be lower as compared to those of the reported values (Alasalvar et al, ; Karabulut et al, ). The induction period of hazelnut oil at 150 °C (27.37 min) was higher than the value reported in our previous study (25.98 min) (Tohma & Turan, ).…”

“…Induction periods of oxidized hazelnut oil samples were determined according to our previous study (Tohma & Turan, ) at 150 °C using the DSC instrument (Shimadzu DSC 60, Tokyo, Japan). For this purpose, 2.0 ± 0.1 mg of oil was weighed into aluminum DSC pan and placed into oven without cover and another pan without sample was kept as reference.…”

Limonene, the compound in essential oil of nutmeg displayed antioxidant effect in sunflower oil during the deep‐frying of Chinese Maye

“…After all, during the frying process, a remarkable part of the frying medium, vegetable oils, is taken up by the fried products to the extent that the sensory properties of the vegetable oils are able to strongly influence the sensory properties of the fried products (Taha et al, 2014;Tohma & Turan, 2015). There is no doubt that the consumer will refuse to use the vegetable oils if the fried products are not attractive to them.…”

Plant species with antioxidant capacity

“…where volatile compounds present as gingerols, shogaols, paradoxes and zingerone have antioxidant activity by elimination of free radicals. To conclude, add that the use of rosemary (Rosmarinus officinalis L.) and sage (Salvia officinalis L.) extracts are already formally accepted in the European regulations as a new food additive and assigned with its number E-392 (Tohma & Turan, 2015).…”