Kenny, Kenny and Puteri, Maria Dewi P. T. Gunawan and Prabawati, Elisabeth K. (2015) Stability Test of Rice Bran Oil in Several Frying Temperatures, Aqueous Systems, and PH Conditions. Bachelor thesis, Swiss German University.

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Abstract

Oil from rice bran is known to have high amount of unsaturated fatty acids and antioxidants. In this study, the oxidative stability, antioxidant activity, and oil unsaturation stability of refined rice bran oil (RBO), in comparison to palm oil (PO) and coconut oil (CO), were observed in the frying process treatments and low pH – aqueous system using dressing as model product. Higher frying temperature and repeated frying increased oxidation, as shown with the increase of peroxide value (PV) up to 13.35 meq/kg. From three times frying process, the highest oxidation was obtained after the first frying. Higher frying temperature and repeated frying also affect the stability of unsaturated fatty acid, as shown with the decrease of iodine value (IV) up to 8.72 cg/g. Antioxidant activity analysis showed that repeated frying decreases antioxidant activity up to 17.29% in 160 ⁰C and up to 26.69% at 240 ⁰C. The higher reduction of antioxidant activity in post-frying-at-240 ⁰C-oil seemed to enhance degree of oxidation and unsaturated fatty acid instability together with exposure to light, as shown with higher rate of PV escalation and IV depletion compared to post-frying-at-160 ⁰C-oil and of course the original rice bran oil. The escalation rate of PV in control was 0.82 meq/kg, compared to 2.33 meq/kg in 160 ⁰C-oil and 2.97 meq/kg in 240 ⁰C-oil. The depletion rate of IV in control was 0.228 cg/g, compared to 2.96 cg/g in 160 ⁰C-oil and 4.16 cg/g in 240 ⁰C-oil. Higher moisture of food in frying enhanced degree of oxidation and unsaturated fatty acid instability with even higher rate. In comparison to PO and CO, RBO was the least stable. Although RBO was the least stable, the unsaturated fatty acids was still higher than PO after three times frying process, but after three days of storage, the IV of RBO was the same compared to IV of PO. Low pH and aqueous system seemed not to affect the oil quality in the beginning and also during storage with low temperature and absence of light exposure. During storage in 25°C without exposure to light, oil quality in the dressing degrades in the similar rate to the original rice bran oil. However, during storage in 25°C exposed to light, the presence of more water and acid seemed to enhance degree of oxidation and unsaturated fatty acid instability significantly higher as shown with higher rate of PV escalation and IV depletion.

Item Type:	Thesis (Bachelor)
Uncontrolled Keywords:	Rice Bran Oil; Stability; Peroxide Value; Oxidative Stability; Iodine Value; Oil Unsaturation; Antioxidant.
Subjects:	Q Science > QK Botany > QK898 Anthocyanins T Technology > TP Chemical technology > TP368 Food processing and manufacture T Technology > TP Chemical technology > TP684 Palm oil > TP684.2 Rice oil
Divisions:	Faculty of Life Sciences and Technology > Department of Food Technology
Depositing User:	Atroridho Rizky
Date Deposited:	28 Dec 2020 16:04
Last Modified:	28 Dec 2020 16:04
URI:	http://repository.sgu.ac.id/id/eprint/1647

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