Influence of industrial physical refining on tocopherol, chlorophyll and beta‐carotene content in sunflower and rapeseed oil

Abstract

The main purpose of this article was to investigate the influence of individual processes in physical refining on tocopherol content in sunflower and rapeseed oils. During refining some chemical parameters, the oxidative stability of oils and some minor compounds such as chlorophyll and betacarotene, were determined. Those analytical data with explained chemical backgrounds gave more qualitative overview of what happened to the same lot of oils being processed in a continuous operation. Some processes were compared with a laboratory oil refining. Crude rapeseed oil contained 656 mg/kg of total tocopherols, followed by high oleic sunflower with 373 mg/kg of tocopherols and classic sunflower oil with 332 mg/kg of tocopherols. The most serious refining processes were bleaching and physical deodorization process, the tocopherol losses being 14.9-17.4% and 20.2-27.1%, respectively. In the refined oils, chlorophylls and FFAs were almost completely removed and the oxidative stability increased 2-3 times. Vegetable oil refining process caused relatively great losses of minor compounds but this, in turn, prolonged the shelf life of edible oils.Practical applications: It was proved that refining of sunflower and rapeseed oils in the oil refinery improves their basic chemical parameters. The loss of tocopherols can be minimized by shortening the time and lowering the temperature during the final step of physical refining, but it has to remain within requirements on quality of refined edible oils.

Effects of refining process on sunflower oil minor components: a review

“…The presence of high levels of free fatty acids, or free acidity, is due to wet harvest conditions which promote the action of lipases generating these molecules, as well as moist grains during storage (Beratlief and Iliescu, 1997). In sunflower oil FFA varied from 1.19 to 1.35% (w/w) in regular sunflower oil (Kreps et al, 2014), from 0.76 to 1.13% in HOHPSO (Marmesat et al, 2008) and can reach up to 4% in HOSO (Moschner and Biskupek-Korell, 2006). FFA are neutralized during the refining process in order to reduce their undesirable effects as undesirable flavor.…”

“…Topkafa et al (2013) found that chlorophyll varied from 403 to 1021 ppb in four crude sunflower oils and β-carotene varied from 1692 to 2803 ppm. The refining process reduces the chlorophylls content up to 96% and 80% the β-carotene content (Kreps et al, 2014).…”

“…Total tocopherols losses during the physical process varied from 24.6 to 54.8% with an average loss of 41% (Alpaslan et al, 2001;Kreps et al, 2014;Tasan and Demirci, 2005). Differences in the amount reduction depend on the nature of sunflower cultivars (i.e.…”

Effect of Fertilizer and Storage Period on Oxidative Stability and Color of Rapeseed Oils

“…During the process of cold-extraction these pigments permeate to oil from seeds in amounts depending on the seed species, environmental conditions, degree of seed maturity, or the storage process. They affect the color of the oil, which is one of the basic quality characteristics of the obtained product, thereby affecting consumer preferences, while they often make the decision to purchase on this basis [12][13][14]. Concerning the content of chlorophyll in seeds, at full maturity stage it usually amounts to 1-2 ppm, while in the case of physiologically matured seed (35 days before maturity) it can be as high as 1,239 ppm [15].…”

Effect of Refining Process on the Quality Characteristics of Soybean and Cotton seed Oils

“…The refining has a positive effect on the oxidative stability of the oil. According to Kreps et al (2014), the refining process removes 79.2% of hydroperoxides from crude oil. Nzikou et al (2009) and Anwar et al (2007) reported peroxide values of 1.67 and 1.27 meq/kg of soybean oil, respectively; these values are lower than those obtained in the present study.…”