Nuru Zehara, Getachew Paulos
Addis Ababa University, College of Natural and Computational Sciences, Center for Food Science and Nutrition, P.O. Box: 1176, Addis Ababa, Ethiopia.
Heliyon. 2021 Apr 8;7(4):e06748. doi: 10.1016/j.heliyon.2021.e06748. eCollection 2021 Apr.
High temperature continuous deep fat frying of foods will result in the frying oil and food quality deterioration. Although the quality can be retained by using fresh oil, this approach will increase the production cost. In this study, quality improvement of used niger seed oil using adsorbent treatment was evaluated. Each adsorbent was mixed with 20 h used niger seed oil (15% w/v) at 150 °C and stirred for 30 min. The oil was recovered through centrifugation at 4200 rpm for 15 min. The tested chemical parameters of the oil increased after 20 h of frying (acid value (AV) (2.24-8.31) mg KOH/gm oil, free fatty acid (FFA) (1.13-4.17) %, and peroxide value (PV) (1.00-13.97 mEq oxygen/Kg of oil). The improvement in free fatty acid, peroxide value and oil recovery upon treatment of the fried oil with ash, bentonite, bleaching earth, silca gel and magnesium oxide (MgO) was (61, 57, 80), (66, 43, 88), (56, 21, 85), (61, 50, 70), and (73, 64, 40) % respectively. Ash and MgO effectively improved the physico-chemical characteristics of the used oil. Thus, the two were selected for further optimization of effective concentration and to evaluate their synergetic effect. Treatments with 2.5, 5.0, 7.5, 10.0, 12.5 and 15.0 % of ash reduced the AV of the fried oil by 26, 39, 46, 53, 53 and 60 % respectively (p < 0.05). Also the combination of ash and MgO (1:1) improved the physico-chemical properties of the frying oil to nearly fresh quality.
对食品进行高温连续深度油炸会导致煎炸油和食品质量下降。虽然使用新鲜油可以保持质量，但这种方法会增加生产成本。在本研究中，评估了使用吸附剂处理对用过的尼日尔籽油质量的改善情况。将每种吸附剂与在150℃下使用20小时的尼日尔籽油（15%w/v）混合，并搅拌30分钟。通过在4200转/分钟下离心15分钟回收油。油炸20小时后，油的测试化学参数增加（酸值（AV）（2.24 - 8.31）mg KOH/克油，游离脂肪酸（FFA）（1.13 - 4.17）%，过氧化值（PV）（1.00 - 13.97 mEq氧/千克油）。用灰分、膨润土、漂白土、硅胶和氧化镁（MgO）处理煎炸油后，游离脂肪酸、过氧化值和油回收率的改善分别为（61、57、80）%、（66、43、88）%、（56、21、85）%、（61、50、70）%和（73、64、40）%。灰分和MgO有效地改善了用过的油的物理化学特性。因此，选择这两种物质进一步优化有效浓度并评估它们的协同效应。用2.5%、5.0%、7.5%、10.0%、12.5%和15.0%的灰分处理分别使煎炸油的AV降低了26%、39%、46%、53%、53%和60%（p < 0.05）。此外，灰分和MgO（1:1）的组合将煎炸油的物理化学性质改善到接近新鲜油的质量。
