JF.Martucci et aL Industrial Crops and Products 71(2015)205-213 209 Table3 Thickness and color parameters of obtained films. Thickness(mm) 1 a b C'ab h'ab △E Ge 0.11±0.01m 89.07±0.16 0.07±0.07a 2.22±0.51a 2.23±0.51m 1.54±0.07 10.81±0.53m 0E02000-Ge 0.10±0.01a 88.95±0.159 0.23±0.09a 2.02±0.60 2.03±0.60 1.46±0.09▣ 10.67±0.710 0E03000-Ge 0.13±0.03° 89.01±0.21 0.23±0.11 1.49±1.09 1.50±1.09 1.42±0.11a 10.25±0.99 0E04000-Ge 0.11±0.02° 89.12±0.40° 0.17±0.12 2.17±1.020 2.18±1.02° 1.49±0.120 10.73±1.08 0E05000-Ge 0.11±0.02° 88.96±0.36 -0.23±0.12 5.12±1.11b 5.13±1.11b -1.52±0.12b 13.56±1.01b 0E06000-Ge 0.13±0.02 88.89±0.17 -0.24±0.06b 4.82±0.530 4.82±0.53 -1.52±0.06 13.35±0.52 LFO2000-Ge 0.07±0.02" 89.00±0.28 -0.29±0.21× 496±0.87严 2.68±0.87 -1.23±0.10 12.55±1.28 LE03000-Ge 0.09±0.02y 88.96±0.68 -0.44±0.20 5.18±1.199 520±2.19 -1.49±0.08 13.71±1.09y LE04000-Ge 0.09±0.02y 88.18±0.60 -0.45±0.38x 5.86±1.259 3.89±125w -1.45±0.11y 12.71±1.39y LE05000-Ge 0.11±0.039 88.52±0.49 -0.60±0.23x 5.74±1.750 5.77±1.752 -1.47±0.13y 14.38±1.83y LE06000-Ge 0.11±0.02 88.02±035 -0.56±0.31× 7.23±1.30 7.25±330 -1.49±0.11 15.94±1.38 Any two means in the same column followed by the same letter are not significantly (P>0.05)different according to Tukey test High radical scavenging activity and reducing power has been antioxidant capacity in relation to the content of oregano essen- observed in the main components of oregano essential oil (car- tial oil.The lower antioxidant activity of the mixture denoted a vacrol,thymol,y-terpinene and p-cymene)(Aeschbach et al.,1994: possible antagonistic effect between their components as previ- Oussalah et al.,2004).However,other compounds could contribute ously observed in the antimicrobial activity.Taking into account to the antioxidant properties of oregano oil. the results reported,EOs mixture was not considered for films for- The antioxidant capacity of the LEO:OEO 50:50 mixture was mulation analyzed by DPPH radical scavenging activity and Ferric reduc- ing power assay.The results obtained indicated a reduction in the 3.2.Properties of EO-added gelatin films 3.2.1.Optical properties 140 OEO Gelatin films added with oregano or lavender essential oils,on an individual basis,were prepared by casting using propylene gly- 120 -0…LE0 △LE0:0E050:50 col as plasticizer and emulsifier.The film optical properties are relevant since they play a major role in the appearance of the coated 100 product.In order to compare the differences between control films and those prepared with the essential oils,Table 3 reports the color 80- (wdd) parameters of the films obtained.Visually:Ge films were quite transparent,though they turned yellowish when the essential oil 60 was added.As far as OEO differences are concerned,they were not significant (P=0.05)up to 3000 ppm of OEO(Table 3).which is 40 consistent with the findings reported by Min and Oh(2009)for cat fish gelatin coatings containing oregano essential oil and Teixeira et al.(2014)for fish gelatin films.On the other hand,LEO-Ge films presented higher C"ab and AE*values and lower h'ab.AE*LEO- Ge values were higher than OEO-Ge ones due to the increase in absorption caused by the interaction between the components.In 1000 2000 3000 4000 5000 6000 LEO-Ge films,Cab values increased with the amount oflavender oil EOs concentration (ppm) added,indicating an increase in yellowish coloration.These results suggested that the incorporation of essential oil influenced film color,though changes depended on the type of essential oil.Ahmad OEO et al.(2012)showed that the incorporation of lemongrass oil in o LEO fish skin gelatin films increased its total color difference,yet there 4 LE0:0E050:50 70 was no difference in the color parameters of the films incorporated with bergamot oil.The considerable effects of the incorporation 60 of cinnamon oil on the color of caseinate-based edible films were IC50oeo:697±89ppm reported by Atares et al.(2010a).However,no marked effect on the color parameters of those films was obtained when ginger oil 40、 was added (Atares et al.,2010a).It was suggested that essential oil also influenced the color of gelatin film,depending on the type and 30 concentrations of the essential oil incorporated. 20 3.2.2.Films morphology 10 The cross-section of Ge control film was compact and smooth without pores or cracks(Fig 2a)in agreement with previous reports (Martucci and Ruseckaite,2009:Tongnuanchan et al.2012).With 1000 2000 3000 4000 5000 6000 the addition of essential oils,the cross-section of films became EOs concentration(ppm) slightly rougher as compared to the control(Fig 2b-e):however. no oil droplets were observed in the film thickness even at the Fig.1.(a)Reducing Power and(b)DPPH radical scavenging activity(RSA)oforegano and lavender essential oils.Bars represent the standard deviation from triplicate highest concentration tested.This result indicates that the film- determinations. forming dispersion was a stable so that no collapse of emulsionJ.F. Martucci et al. / Industrial Crops and Products 71 (2015) 205–213 209 Table 3 Thickness and color parameters of obtained films. Thickness (mm) l * a* b* C*ab h*ab E* Ge 0.11 ± 0.01ax 89.07 ± 0.16ax 0.07 ± 0.07 a 2.22 ± 0.51a 2.23 ± 0.51ax 1.54 ± 0.07a 10.81 ± 0.53ax OEO2000-Ge 0.10 ± 0.01a 88.95 ± 0.15a 0.23 ± 0.09a 2.02 ± 0.60a 2.03 ± 0.60a 1.46 ± 0.09a 10.67 ± 0.71a OEO3000-Ge 0.13 ± 0.03a 89.01 ± 0.21a 0.23 ± 0.11a 1.49 ± 1.09a 1.50 ± 1.09a 1.42 ± 0.11a 10.25 ± 0.99a OEO4000-Ge 0.11 ± 0.02a 89.12 ± 0.40a 0.17 ± 0.12a 2.17 ± 1.02a 2.18 ± 1.02a 1.49 ± 0.12a 10.73 ± 1.08a OEO5000-Ge 0.11 ± 0.02a 88.96 ± 0.36a -0.23 ± 0.12b 5.12 ± 1.11b 5.13 ± 1.11b -1.52 ± 0.12b 13.56 ± 1.01b OEO6000-Ge 0.13 ± 0.02a 88.89 ± 0.17a -0.24 ± 0.06b 4.82 ± 0.53b 4.82 ± 0.53b -1.52 ± 0.06b 13.35 ± 0.52b LEO2000-Ge 0.07 ± 0.02y 89.00 ± 0.28x -0.29 ± 0.21x 4.96 ± 0.87x 2.68 ± 0.87x -1.23 ± 0.10x 12.55 ± 1.28x LEO3000-Ge 0.09 ± 0.02xy 88.96 ± 0.68x -0.44 ± 0.20x 5.18 ± 1.19xy 5.20 ± 2.19y -1.49 ± 0.08y 13.71 ± 1.09xy LEO4000-Ge 0.09 ± 0.02xy 88.18 ± 0.60x -0.45 ± 0.38x 5.86 ± 1.25xy 3.89 ± 1.25xy -1.45 ± 0.11y 12.71 ± 1.39xy LEO5000-Ge 0.11 ± 0.03xy 88.52 ± 0.49x -0.60 ± 0.23x 5.74 ± 1.75xy 5.77 ± 1.75yz -1.47 ± 0.13y 14.38 ± 1.83y LEO6000-Ge 0.11 ± 0.02x 88.02 ± 0.35x -0.56 ± 0.31x 7.23 ± 1.30y 7.25 ± 3.30z -1.49 ± 0.11y 15.94 ± 1.38y * Any two means in the same column followed by the same letter are not significantly (P > 0.05) different according to Tukey test. High radical scavenging activity and reducing power has been observed in the main components of oregano essential oil (car￾vacrol,thymol, -terpinene and p-cymene)(Aeschbach et al., 1994; Oussalah et al., 2004). However, other compounds could contribute to the antioxidant properties of oregano oil. The antioxidant capacity of the LEO:OEO 50:50 mixture was analyzed by DPPH radical scavenging activity and Ferric reduc￾ing power assay. The results obtained indicated a reduction in the Fig. 1. (a) Reducing Power and (b) DPPH radical scavenging activity (RSA) of oregano and lavender essential oils. Bars represent the standard deviation from triplicate determinations. antioxidant capacity in relation to the content of oregano essen￾tial oil. The lower antioxidant activity of the mixture denoted a possible antagonistic effect between their components as previ￾ously observed in the antimicrobial activity. Taking into account the results reported, EOs mixture was not considered for films for￾mulation. 3.2. Properties of EO-added gelatin films 3.2.1. Optical properties Gelatin films added with oregano or lavender essential oils, on an individual basis, were prepared by casting using propylene gly￾col as plasticizer and emulsifier. The film optical properties are relevant since they play a major role in the appearance ofthe coated product. In order to compare the differences between control films and those prepared with the essential oils, Table 3 reports the color parameters of the films obtained. Visually; Ge films were quite transparent, though they turned yellowish when the essential oil was added. As far as OEO differences are concerned, they were not significant (P ≥ 0.05) up to 3000 ppm of OEO (Table 3), which is consistent with the findings reported by Min and Oh (2009) for cat fish gelatin coatings containing oregano essential oil and Teixeira et al. (2014) for fish gelatin films. On the other hand, LEO-Ge films presented higher C*ab and E* values and lower h*ab. E* LEO￾Ge values were higher than OEO-Ge ones due to the increase in absorption caused by the interaction between the components. In LEO-Ge films, C*ab values increased with the amount oflavender oil added, indicating an increase in yellowish coloration. These results suggested that the incorporation of essential oil influenced film color,though changes depended on the type of essential oil. Ahmad et al. (2012) showed that the incorporation of lemongrass oil in fish skin gelatin films increased its total color difference, yet there was no difference in the color parameters of the films incorporated with bergamot oil. The considerable effects of the incorporation of cinnamon oil on the color of caseinate-based edible films were reported by Atarés et al. (2010a). However, no marked effect on the color parameters of those films was obtained when ginger oil was added (Atarés et al., 2010a). It was suggested that essential oil also influenced the color of gelatin film, depending on the type and concentrations of the essential oil incorporated. 3.2.2. Films morphology The cross-section of Ge control film was compact and smooth without pores or cracks (Fig 2a)in agreement with previous reports (Martucci and Ruseckaite, 2009; Tongnuanchan et al., 2012). With the addition of essential oils, the cross-section of films became slightly rougher as compared to the control (Fig 2b–e); however, no oil droplets were observed in the film thickness even at the highest concentration tested. This result indicates that the film￾forming dispersion was a stable so that no collapse of emulsion