• The Korean Journal of Food And Nutrition
• /
• v.27 no.3
• /
• pp.339-347
• /
• 2014

This study investigated the classification of olive oils that are mainly distributed in Korea via imports. The fatty acid contents, degree of color, pigments, anti-oxidants, and sterol contents are analyzed on the different types of olive oil as follows: 10 kinds of extra virgin olive oil, 5 kinds of pure olive oil, and 5 kinds of refined olive-pomace oil. As a result of fatty acid analysis, the majority of oleic acid ($C_{18:1}$) and palmitic acid ($C_{16:0}$), and minority of linoleic acid ($C_{18:2}$) and stearic acid ($C_{18:0}$) were detected without any significant differences between the grades of olive oils. The UV spectrum is related to the ${\Delta}K$, and it is a part of the analysis factor for the purity and degree of degradation of the oil. Extra virgin olive oil had ${\Delta}K$ of almost 0, pure olive oil had 0.07~0.12, and refined olive-pomace oil had 0.1~0.13. These differed from extra virgin oil, and the pure or pomace oil ${\Delta}K$ had a confirmed distinct difference. The color degrees of chlorophyll with a low $L^*$ value and $(-)a^*$ (green) and carotenoid with $(+)b^*$ (yellow) were confirmed to have correlation between extra virgin and other olive oils. To compare chlorophyll and carotenoid as natural pigment in olive oils, 417 nm and the ratio of the absorbance at 480 nm (417/480) was calculated at 1.62 of extra virgin, 1.85 of pure olive oil, and 3.32 of refined olive-pomace oil. Therefore, it will be possible to distinguish when the extra virgin or pure olive oil are mixed with olive-pomace oil. The total amount of tocopherol, an anti-oxidant, were 19.06 in extra virgin, 10.91 in pure olive oil, and 27.88 in refined olive-pomace oil. The high content of tocopherol in pomace oil caused recovery of solvent extraction from olive pulp. Thus, extra virgin oil and pure olive oil were distinguished by olive-pomace oil. Polyphenol compounds in extra virgin olive oil measured high only in ferulic acid with 0.543 mg/kg, caffeic acid with 0.393 mg/kg, and other vanillic acid, vanillin, and p-coumaric acid had similar amount of 0.3 mg/kg. All grade of olive oils had the highest ${\beta}$-sitosterol content. Af (Authenticity factor) value were estimated with campesterol and stigmasterol content ratio (%). Af value was 19.2 in extra virgin olive oil, 17.1 in pure olive oil, 16.9 in refined olive-pomace oil, which were distinctive from sunflower oil with 3.7, corn oil with 2.4, and soybean oil with 2.0. It can provide important indicator of olive oil adulteration with other cheap vegetable oils. The results of this study can be used as a database for the classification of olive oil grade and distinguishing between the different types of oils.

• Korean Journal of Food Science and Technology
• /
• v.35 no.6
• /
• pp.1064-1071
• /
• 2003

An investigation of various olive oils available in Korea was carried out to assess their quality properties such as color, oxidative stability, fatty acid composition, tocopherol content, sterol content and benzo(a)pyrene content. In color measurement, by using a Lovibond color scale and Hunter color difference meter, both a and b values of extra virgin olive oil were higher than those of pure olive oil by Tintometer (Lovibond PFX995). However, extra virgin olive oil showed higher a value and lower L value than pure olive oil by the Hunter color difference meter. In the rancimat test, the induction period of extra virgin olive oil $(38.03{\sim}8.47hr)$ was longer than that of pure olive oil $(32.40{\sim}9.94hr)$. In fatty acid composition, C18:1 $(72.01{\sim}78.53wt%)$ was present in the greatest amount, with lesser amounts of C18:2 $(4.88{\sim}10.36wt%)$ and C18:3 $(0.56{\sim}1.09wt%)$. The tocopherol content ranged from ${\alpha}-Toc\;4.09{\sim}13.89mg/100g$, ${\beta}-Toc\;0.57{\sim}1.34mg/100g$, and ${\gamma}-Toc$ $3.41{\sim}8.03mg/100g$, and ${\alpha}-tocopherol$ was found to be the main isomer in all oil samples. Therefore, there was little difference in the fatty acid composition and tocopherol content among the different types of olive oils. In sterol content, ${\beta}-sitosterol$ $(124.52{\sim}19.33mg/100g)$ and campesterol $(1.10{\sim}0.62mg/100g)$ of extra virgin olive oil were higher than that of pure olive oil $({\beta}-sitosterol\;92.68{\sim}17.44mg/100g,\;campesterol\;0.59{\sim}0.35mg/100g)$. Benzo(a)pyrene was found in almost all samples, with $0.287{\sim}0.106{\mu}g/kg$ in extra virgin olive oil and $1.204{\sim}2.130{\mu}g/kg$ in pure olive oil.

• Korean journal of food and cookery science
• /
• v.28 no.3
• /
• pp.265-273
• /
• 2012

The purpose of this study was to determine the effects of the duration of frying and storage periods on physicochemical characteristics of various oils using at home. The materials used for the study consisted of four kinds of vegetable oils: soybean, canola, extra virgin olive and pure olive oils, and shortening. Chicken breasts were fried in oils heated at $180^{\circ}C$. The oils were stored with or without filtering and reused 3 times, during the 10 day period. The extra virgin and pure olive oils showed higher acid, peroxide value and yellowness than the other oils (p<0.05), but soybean oil showed the highest increase in acid, peroxide value and yellowness with reusing and storage. In sensory evaluation, the chicken breast fried with soybean oils remarkably decreased the overall acceptance. These results suggested that all frying oils are available because acid and peroxide values of the oils are lower than the standard level. However, reusing soybean oil should be noted with caution in that it is very easy to reduce rancidity, and extra virgin olive oil is not appropriate for frying.

• Food Science and Biotechnology
• /
• v.16 no.3
• /
• pp.415-420
• /
• 2007

The aim of this study was to determine the various bioactive components of five olive oil varieties, as well as to assess their contribution to the oxidative stability of the oils. Fatty acids, ${\alpha}$-tocopherol, ${\beta}$-carotene, total flavonoids, total phenols, and certain phenolic compounds of extra virgin olive oils (EVOO; blended, arbequina, hojiblanca, and picual) and pure olive oil (POO) were examined. Oxidation stability was evaluated by the peroxide value (POV). The total content of all the studied antioxidant compounds was significantly higher in the EVOOs than the POO (p<0.05). Among the EVOOs, picual had the highest levels of ${\alpha}$-tocopherol ($10.18{\pm}0.40\;mg/100\;g$), ${\beta}$-carotene ($557{\pm}8\;{\mu}g/100\;g$), and total phenols ($110.7{\pm}1.3\;mg/g$), which correlated strongly with antioxidative capacity. Furthermore, the lowest POV occurred in picual EVOO and correlated with the highest monounsaturated fatty acid (MUFA, C16:1 and C18:1) and lowest polyunsaturated fatty acid (PUFA, C18:2 and C18:3) compositions, suggesting the ratio of MUFA to PUFA is a critical parameter for the oxidative stability of olive oil. Our results indicate that the oxidative stability and antioxidant potential of EVOO depends not only on the antioxidant vitamins, but also on the amount of phenolic compounds and fatty acid profile of the oil.

• Culinary science and hospitality research
• /
• v.12 no.4 s.31
• /
• pp.80-96
• /
• 2006

The purposes of this study were twofold. First, it aimed to develop the olive-oil liaison (Roux). Second, it tried to examine customer perceptions of the olive-oil liaison compared with commonly used butter liaison in hotel restaurants. The theme of the study was derived from the present trend of pursuing healthy food so-called 'well-being'. As a result, the extra virgin olive-oil liaison(Roux) with the optimal ratio of 1.4 : 1 (flour: olive-oil) was developed through repeated sensory tests. The findings also showed that customers prefer products with the olive-oil liaison to products with butter liaison in terms of satisfaction and intention to re-purchase.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.36 no.7
• /
• pp.866-873
• /
• 2007

To analyze and differentiate volatile compounds of 13 extra virgin olive oils from market, solid-phase micro extraction (SPME) GC-MS and electronic nose (EN) equipped with metal oxide sensors were applied. The volatiles identified in extra virgin olive oils include hexanal, 4-hexen-1-ol, (Z)-3-hexen-1-ol, acetic acid, and 2,4-dimethyl-heptane, etc. Response from EN was analysed by the principal component analysis. Proportion of the first Principal component was 99.70%, suggesting that each aroma pattern of the 13 extra virgin olive oils could be discriminated by EN. Fatty acid compositions were oleic (61.1${\sim}$77.9 mole%), palmitic (11.7${\sim}$16.5 mole%), linoleic (4.7${\sim}$9.7 mole%), stearic (2.5${\sim}$2.9 mole%), Palmitoleic (0.8${\sim}$2.4 mole%), and linolenic acid (0.7${\sim}$1.2 mole%). In color study, extra virgin olive oil showed $L^{\ast}$ value of 81.7${\sim}$92.9, $a^{\ast}$ value of -28.3${\sim}$13.5 and $b^{\ast}$ value of 52.2${\sim}$139.0. Total phenol and ${\alpha}-tocopherol$ contents were 6.2${\sim}$24.9 mg/100 g and 5.5${\sim}$12.8 mg/100 g, respectively. In Rancimat test, the induction period of 13 extra virgin olive oils showed 31.76${\sim}$54.04 hr while their POV ranged from 13.5 to 22.9 meq/kg oil.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
• /
• 2001.06a
• /
• pp.1520-1520
• /
• 2001

Food adulteration is a serious consumer fraud and a potentially dangerous practice. Regulatory authorities and food processors require a rapid, non-destructive test to accurately confirm authenticity in a range of food products and raw materials. Olive oil is prime target for adulteration either on the basis of the processing treatments used for its extraction (extra virgin vs virgin vs ordinary oil) or its geographical origin (e.g. Greek vs Italian vs Spanish). As part of an investigation into this problem, some preliminary work focused on the ability of near infrared spectroscopy to discriminate between virgin olive oils from separate regions of the Mediterranean i. e. Crete and the Peloponese. A total of 46 oils were collected: 18 originated in Crete and 28 in the Peloponese. Oils were stored in a temperature-controlled room at 2$0^{\circ}C$ prior to spectral collection at room temperature (15-18$^{\circ}C$). Samples (approximately 0.5$m\ell$) were placed in the centre of the quartz window in a camlock reflectance cell; the gold-plated baking plate was then gently placed into the cell against the glass so as to minimize the formation of air bubbles. The rear of the camlock cell was then screwed into place producing a sample thickness of 0.5mm. Spectra were recorded between 400 and 2498nm at 2nm intervals on a NIR Systems 6500 scanning monochromator. Spectral collection took place over 2-3 days. Data were analysed using both WINISI and The Unscrambler software to investigate the possibility of discriminating between the oils from Crete and the Peloponese. A number of data pre-treatments were used and discriminant models were developed using discriminant PLS (WINISI & Unscrambler) and SIMCA (Unscrambler). Despite the small number of samples involved, a satisfactory discrimination between these two oil types was achieved. Graphical examination of principal component scores for each oil type also holds out the possibility of separating oils from either Crete and the Peloponese on the basis of districts within each region. These preliminary data suggest the potential of near infrared spectroscopy to act as a screening technique for the confirmation of geographic origin of extra virgin olive oils. The sample presentation strategy adopted uses only small volumes of material and produces high quality spectra.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.35 no.10
• /
• pp.1405-1411
• /
• 2006

The presence and content of residual hexane in the olive oils were studied. Total 41 olive oils of imported and domestic brands, which were labeled as extra virgin and refined (mixed), were collected from the market. For analysis, electronic nose and headspace SPME-GC/MS were used. Electronic nose equipped with 12 metal oxide sensors was used for the discrimination of odor pattern of olive oils against the different concentrations of hexane. From the results, it is assumed that the contents of residual hexane in the collected olive oils were below 5 ppm. For Qualitative and quantitative analysis of hexane, polydimethylsiloxane (PDMS) fiber was employed for SPME-GC/MS. In the results, the peak of residual hexane was detected in 8 samples from 41 olive oils. But the detected level was no more than 1 ppm that is under the regulation limit (5 ppm) by Korea Food Additive Code.

• Korean journal of food and cookery science
• /
• v.27 no.3
• /
• pp.39-49
• /
• 2011

This study was conducted to evaluate the effects of adding unrefined oil on the antioxidant activity of a tuna oil-enriched emulsion by determining DPPH radical scavenging activity, reducing power, and inhibition of low-density lipoprotein (LDL) oxidation in vitro. The emulsion consisted of tocopherol-stripped canola (18.3 g) and tuna (9.1 g) oil, one of the unrefined oils (4.6 g), such as extra virgin olive, mustard, perilla, or sesame oil, 0.5% acetic acid (64 g), and egg yolk powder (4 g). The control emulsion contained only canola (21.4 g) and tuna oil (10.6 g), as oil sources,with the same composition of the remaining ingredients. The emulsion with added unrefined oil, particularly mustard oil, showed higher radical scavenging activity and reducing power than those of the control emulsion. The radical scavenging activity and reducing power of the emulsion with added unrefined oil were higher at 1,000 ppm than at 500 ppm thus, the effect was concentration-dependent. Adding sesame or perilla oil to the tuna oil-enriched emulsion resulted in higher inhibition of LDL oxidationwhereas adding olive oil increased LDL oxidation. The results clearly showed that adding roasted mustard, sesame, or perilla oil improved the antioxidant activity of a tuna oil-enriched emulsion by increasing free radical scavenging activity, reducing power, and inhibiting LDL oxidation. The results also suggest that adding unrefined oils produces a healthier fish oil-enriched salad dressing recipe.

• Parasites, Hosts and Diseases
• /
• v.54 no.4
• /
• pp.527-532
• /
• 2016

Head lice, Pediculus humanus capitis, infestation is an important public health problem in Egypt. Inadequate application of topical pediculicides and the increasing resistance to the commonly used pediculicides made the urgent need for the development of new agents able to induce irreversible changes in the exposed lice leading to their mortality. The aim of the present work is to evaluate pediculicidal efficacy of some natural products such as olive oil, tea tree oil, lemon juice, and ivermectin separately in comparison with tetramethrin-piperonyl butoxide (licid), as a standard pediculicide commonly used in Egypt. The effects of these products were evaluated by direct observation using dissecting and scanning electron microscopes (SEM). Results showed that after 1 hr exposure time in vitro, absolute (100%) mortalities were recorded after exposure to 1% ivermectin and fresh concentrate lemon juice. The mortalities were decreased to 96.7% after exposure to tea tree oil. Very low percentage of mortality (23.3%) was recorded after 1 hr of exposure to extra virgin olive oil. On the other hand, the reference pediculicide (licid) revealed only mortality rate of 93.3%. On the contrary, no mortalities were recorded in the control group exposed to distilled water. By SEM examination, control lice preserved outer smooth architecture, eyes, antenna, respiratory spiracles, sensory hairs, and legs with hook-like claws. In contrast, dead lice which had been exposed to pediculicidal products showed damage of outer smooth architecture, sensory hairs, respiratory spiracles and/or clinching claws according to pediculicidal products used.