ORIGINAL ARTICLE Effects of Storage Conditions

694 Advances in Environmental Biology, 6(2): 694-701, 2012 ISSN 1995-0756

This is a refereed journal and all articles are professionally screened and reviewed

ORIGINAL ARTICLE

Effects of Storage Conditions and PET Packaging on Quality of Edible Oils in Iran 1

Mousavi Khaneghah, 2Sh. Shoeibi, and 3M. Ameri

1

Department of Food Science and Technology, Islamic Azad University, Science and Research Branch, Tehran, Iran. 2 Food and Drug Control Laboratories (FDCLs), Deputy for Food & Drug, MOH, Tehran, Iran. 3 Head of R&D Lab. Savola Behshahr Ind. Co., Tehran, Iran. Mousavi Khaneghah, Sh. Shoeibi and M. Ameri: Effects of Storage Conditions and PET Packaging on Quality of Edible Oils in Iran ABSTRACT The Effects of polyethylene terephthalate (PET) pieces and different storage conditions on fatty acids profile and some quality factors in three types of commercial oils, namely sunflower oil, canola oil, and blended oil containing sunflower oil, soy bean oil, and cottonseed oil were studied. Fatty acid profile and quality factors such as peroxide value, free fatty acids, and iodine value and induction period before and after storage of samples at 25 and 45°C for 20 and 60 days in the presence or absence of PET pieces were investigated. Results showed that the amount of polyunsaturated fatty acids like linoleic acid was decreased slightly and the amount of monounsaturated and saturated fatty acids like oleic acid and palmitic acid, respectively, was marginally increased. Thus, it was concluded that the stability of vegetable oils is dependent on the type of oil and its initial physical and chemical properties, time and temperature of storage and the type of employed packaging material (PET and glass). This study showed that storing oils at low temperatures (T transparent glass > PET [6]. Oil quality can be controlled by measuring peroxide value, acid number and thiobarabituric acid value [30]. Satue et al. [28] reported that the extent of oil oxidation is often specified by measuring the peroxide value (PV). Since this index is related to the hydroperoxides, the primary oxidation products which cause rancid flavor because of their instability and hence conversion to secondary oxidation products [19,28]. Kucuk and Caner [21] studied the effect of PET packaging materials and the various keeping conditions on storage stability of sunflower oil. The results showed that PET packaging, presence of oxygen, light and storage period increased the peroxide value, free fatty acids and iodine value in addition to soap content compared with glass packing in the above mentioned conditions [21], in this case they leave a great impression on decreasing the oil storage stability. The effect of different type of plastics (polyethylene terephthalate (PET), polyvinylchloride (PVC), polypropylene (PP) and polystyrene (PS) on the stability of olive, sunflower and palm oil were studied [32]. The authors have concluded that the period and temperature of storage as well as

packaging materials have significant effects on the stability of the above mentioned oils [32]. Tawfik [33] studied the oil absorption and the global migration of different types of plastic material (PET, PVC, PP and PS) into different vegetable oils (olive, sunflower and palm oil). The findings showed that the amount of overall migration from plastic packaging into a vegetable oil is determined by the type of plastic packaging and the kind of oil considered. Tawfik concluded that the chain length of the fatty acids and the degree of saturation clearly influence the oil absorption by polymers whereas the migration of components from plastic was not influnced that much [33]. The present study examined the effects of PET plastic pieces and various storage conditions on fatty acid profile and some quality factors. Hence, Fatty acid profile and quality factors such as peroxide value, free fatty acids and iodine value and induction period before and after storage of samples at 25 and 45°C for 20 and 60 days in presence or absence of PET pieces in three types of common oils from Iran’s market were investigated. Materials And Methods Oils and PET bottles: Commercial sunflower, canola and blended oils (contains sunflower, soy and cotton seed oils) (amount of added B.H.T as antioxidant 100 mg/kg in all of the oils) and PET bottles were obtained from Savola Behshahr Co., Tehran. Iran. Chemicals solvents were purchased from Merck Co., Germany. Sample Preparation: After measuring a specific surface on the bottles, they were cut to14 pieces with the same size (surface of them are 6 cm2). Pieces were placed in 250ml Glass vessels, the glass vessels were poured with oil up to 150ml volume of container, so that the test pieces were always remained well apart from one to another and immersed completely in each type of oil. The glass vessels that contain tests pieces were stored at 25 and 45°C for 20 and 60 days [33]. Since all of the samples have been stored in a dark place and in sealed container (in glass vessels 250 ml) the effect of light and oxygen parameters in all specimens were similar. The temperature were controlled and the data recorded by data logger (LASCAR, England). Glass vessels containing oils only were placed in the same conditions and served as blank samples. Every treatment was performed in four replicates. Chemical Tests: For determination the profile of fatty acid, a transmethylation technique followed by GC-FID determination [2] was used as practice method. The

6996 Adv. Enviroon. Biol., 6(2): 6994-701, 2012

gas chrom matograph system (Agilent Technologiess model 68 890N, German ny) equippedd with flamee ionization detector (FID)) and HP88 coolumn with thee [ was usedd specificatioons of 100m*2250mm*0.2m [1,2] as practicee method. Tem mperature of th he column hass raised from m 170 to 190°C C in 5 minutes and 0.5°C perr minute annd remained in i this tempeerature for 200 minutes, th he detector tem mperature was at 250°C, thee carrier gass was helium at 0.7ml/min, the pressuree was 10 PSII and the amou unt of sample injection was 1 micro liter [1,7]. ystem (Metrohhm model 734,, By usiing rancimat sy Switzerlannd) and AOCS S (Cd 12b-92) the inductionn period test was done at 110 °C [7]. The iodine i value was calculatted based onn mathematical formula whhich presentedd in AOCS (Cdd c from m the oil fattyy 1c-85), whhich directly calculated acid profile (Firestone, 1994). 1 In oxidaative rancidityy oxygen is taken by thee oil with the formation off peroxide. The degreee of peroxidde formationn c acccording to thee (Peroxide Value) was calculated D of free fattyy AOCS (Cdd 8-63) [7]. Determination acids was done d by AOCS S (Cd 3d-63) [77]. Statistical Analysis: A Experiiments on eachh of samples were w performedd at four tim mes. Two analyyses were taken n from the testt samples at a each speciffic time intervval. Statisticall analysis (M Mean values and standard division weree calculated at each time innterval, so werre analyzed byy SPSS verr. 17 (SPSS Inc. Michiggan Avenue.,, Chicago, USA) U and Miniitab ver. 11.12 (Minitab Inc.,, USA). nd Discussions Results An Tabless 1, 2 and 3 shows thee fatty acidss compositioon of sunflower oil, blended oil o (sunflower,, soybean an nd cotton seed ds oils) and cannola oil beforee and after storage s for 20 and a 60 days att 25 and 45°C.. As it is shhown in resultss, some small changes c in thee amounts of o saturated annd unsaturated fatty acids inn above men ntioned oils were observed. Main fatty acids inn the sunflower oil includee o acid 23.337(%), linoleicc palmitic accid 7.74(%), oleic acid 61.76(%) and lin nolenic acid 1.63(%) thatt t amount off slightly altterations weree detected in the mentioned fatty acids affter storage. As A an examplee the profilee of the sunnflower oil was w altered too palmitic acid a 8.7(%), oleic acid 25.15(%), 2 andd linoleic aciid 57.83(%) affter 60 days sto orage at 45°C.. As result the t amount of poly unsaturaated fatty acidss like linoleiic acid was deecreased and the t amount off mono unsaaturated and saaturated fatty acids a like oleicc acid, and palmitic p acid, reespectively, weere increased. Most notable fatty acids in thee blended oill include paalmitic acid 9.4 43(%), oleic acid a 23.80(%),, linoleic accid 58.00(%) and linolenic acid 2.42(%)) that some slight changees were observved, similar too

sunfloweer oil, after sstorage. The composition of indicatedd fatty acids w was changed to t palmitic accid 9.63(%), oleic acid 24.79(%), and linoleic accid 55.56(%)) after 60 days storage for at 45°C. In canola oil withh this initial faatty acid profille: palmitic acid 5.07(%),, oleic acid 566.01(%), linoleeic %) small changges acid 20.994(%), linoleniic acid 9.15(% in fatty acid a profile waas observed aftter storage at thhe same connditions. Effeects of timee passing annd raising of temperatture caused breeaking 2 cis do ouble bonds annd convertinng them to sinngle double bo ond and withoout double bonds, Also, the converssations betweeen metrical isomeerization such as different shape of geom Cis or Trrans and local isomerization such Iso causeed above meentioned alteraation [31]. Sincce all of the saamples have been b stored in a dark placce and in sealled container (in ( glass vesseels 250 ml) the effect of liight and oxygeen parameters in milar. Presencce or absence of all specimens were sim plastic pieces has no significant effect on fatty acids profile ording the resuults which is shown s in Fig. 1, Acco significannt decrease (P≤0.05) waas observed at inductionn period (IP) in the mentiioned oils aftter storage for f 20 and 60 days at 25 annd 45°C. Amonng the oils,, canola has maximum innduction periood because this oil containn a large amou unt of oleic fattty ono unsaturatedd) and the blen nded oil has thhe acid (mo minimum m induction peeriod because the oil containns different types of fatty acids such as poly p unsaturateed fatty aciids. A signifficant differennce (P≤0.05) at inductionn period was observed in the presence or absence of plastic piecces. These diffferences indicaate the effecct of plastic pieces on decreeasing inductioon period and a correlates with previou us investigationns [14,21]. In the case of the blended oiil, the significaant 6 days at 45 C decreasinng in inductionn period after 60 has madee the oil uselesss, with consider to blended oil o standard (maximum auuthorized of indduction period is 8 hours) [16,15,17]. Thhe result shows that the canoola oil has thhe maximum innduction perio od in comparisoon with otheer oils. As shown s in Fig. 2, sunflower and a blended oiils have inccreased signifi ficantly (P≤0.0 05) in peroxidde value (PV V) after 20 annd 60 days at 25 2 and 45°C annd in the presence or absence of PET pieces but in canola oil only period and temperatture has affecteed significanntly (P≤0.05) in peroxide value. v In blendeed oil that contains diffferent types of fatty acidds; peroxidee value was foormed quicklyy because of thhe large am mount of pooly unsaturateed fatty acidds. Peroxidees in sunfloweer and canola oil was formeed slower th han blended oil due to the presence p of higgh amount of o natural antiooxidants and mono m unsaturateed fatty acidds like oleic acid, a respectiveely [21,18,4] bbut during storing s and affter decreasinng efficiency of natural antioxidants a annd decreasing amount a of monno unsaturatted fatty acids the amount off peroxide valuue has incrreased in suunflower and canola oil in


comparison n with the innitial oils. In presence andd absence off plastic pieces, the sunflow wer and canolaa oil has inccreased signifiicantly (p≤0.05 5) in peroxidee value afterr 20 and 60 days at 45°C. Relatively, R thee PVs have been altered at a the end of storage s period,, b increased d as a result off releasing proo and have been oxidant coompounds suchh as aldehydes from plasticc pieces. Moreover, M it has been stimulated s byy increasing temperature. This T result wass confirmed byy m previous investigationss [14,9,21,11]. Maximum authorized value of peroxide in Nationnal standard off Iran for suunflower, canoola and blended oils are 2.5,, 2.0 and 5.00 meq/kg, resppectively, so based b on thesee values, sun nflower oil which stored at 45°C in both off storage perriods, canola oil o which storeed at 45°C forr 60 days annd blended oill that stored at a 45°C for 200 days with plastic piecees, 60 days with w and alsoo without plastic pieces became useleess [16,1517].. Results shoow that canolaa oil has the minimum m PV inn comparison n with other oils at the ennd of storagee period. odine value (IIV) is decreassed during thee The Io storage peeriod as shownn in Fig. 3. The T amount off unsaturatedd fatty acid haas a direct effect on IVs. Ass the result existence e of pooly unsaturated d fatty acids inn the blended and sunflow wer oil, The IVs in sunflowerr and blendeed oil significaantly declined (P≤0.05) afterr 60 days att 45°C and in presence or abbsence of PET T pieces. Sliight changes after decreasiing of iodinee

value inn canola oil were observeed. The Resullts correlatees with the prevvious investigaations [32]. Amoounts of free fatty acids (FFA%) durinng different conditions of storage were shown in Fig. 4. It is welll accepted thatt during storagge period, partiial hydrolyssis of oils has taken place, thuus free fatty accid content were increaseed. There waas a significaant increase (P≤0.05) in thhe FFA% am mong the storagge for 20 and a 60 days aat 25,45°C in mentioned oiils which shhows the effecct of temperatu ure and time on o forming free fatty aacids, and alsso confirm thhe previous investigationns [13,29,9,111]. FFA% haad i presence or increasedd significantlyy (P≤0.05) in absence of the plastic pieces in the oils. Releasinng lower mo olecular acids from plastic pieces p which are a stimulateed by increaasing temperatture cause thhe Increasinng of FFA %. These reesults were in accordan nce with earlieer research [113]. In Nationnal standard of Iran, the m maximum perm missible level of y acids in sunfflower, canola and blended ooil free fatty are 0.2, 0.2 0 and 0.1%, respectively, thus t the blendeed oil whichh had been storred at 450C forr 20 and 60 dayys with andd without plaastic pieces was w deteriorateed [15,16,17 7]. It is neceessary to be noticed n that thhe presencee of free fatty acids increasees the hydrolyssis which leeads deterioraation of oils and a make theem unsuitablle for human consumption. Results R show thhat the canoola oil has the maximum lev vel of free fattty acids in comparison c wiith the other oills.

Table1: Profi file of fatty acids in n sunflower oil in different conditionns of storage Storage connditions Original* oil 20 days 20 daays fatty acid Without PET T pieces** Withh PET pieces*** 25 45 25 45 C14:0 0.08 0.08 0.08 0.08 0.08 C16:0 7.55 7.93 8.02 8.06 7.98 C16:1 0 0.09 0.08 0.09 0.09 C17:0 0.05 0.05 0.05 0.05 0.05 C18:0 2.97 4.03 4.10 4.03 3.93 T -C18:1 0 0.04 0.06 0 0.03 C18:1 23.37 24.95 24.96 25.233 24.69 Iso-C18:1 1.73 1.07 1.15 1.00 1.23 T-C18:2 0.26 0.33 0.35 0.36 0.35 C18:2 61.76 57.94 57.94 57.877 58.20 C20:0 0.16 0.30 0.30 0.31 0.29 T-C18:3 0 0.18 0.18 0.09 0.18 C18:3 1.67 1.98 1.94 1.97 1.97 Iso-C18:3 0 0.07 0.04 0 0.06 Ga-C18:3 0.18 0.17 0.16 0.16 0.15 C22:0 0.20 0.61 0.58 0.59 0.56 Original oil *: * The oil which haas no treatment Without PET pieces**: The oil which has not beeen in contact withh PET pieces w has been in contact c with PET pieces p With PET pieeces***: The oil which Table 2: Proffile of fatty acids in i blended oil in diifferent conditionss of storage Storage connditions 20 dayys Original oil 20 days p With P PET pieces*** fatty acid Without PET pieces** C14:0 C16:0 C16:1 C17:0

0.11 9.43 0.07 0.04

25 0.12 9.65 0.10 0.06

45 0.12 9.62 0.10 0.06

25 0.11 9.65 0.09 0.06

45 0.12 9.77 0.10 0.06

60 days Without PET pieces p

ys 60 day With PET pieces

25 0.07 7.81 0.08 0.04 3.63 0 24.32 1.63 0.24 59.33 0.22 0.15 1.87 0 0.1254 0.35

25 0.08 8.08 0.08 0.05 3.94 0 24.95 1.11 0.35 58.25 0.2 0.14 1.96 0 0.14 0.53

445 00.07 77.85 0 0 33.63 00.02 224.10 11.90 00.21 559.42 00.21 00.15 11.87 0 00.12 00.32

45 0.08 8.07 0.08 0.05 4.01 0 25.15 1.19 0.35 57.83 0.30 0.16 1.93 0 0.15 0.57

60 days Without PET pieces

60 day ys With PET P pieces

25 0.11 9.4221 0.08 0.04

25 0.11 9.60 0.09 0.06

455 0.12 9.77 0 0

45 0.12 9.63 0.10 0.06

6998 Adv. Enviroon. Biol., 6(2): 6994-701, 2012 C18:0 3.33 4.00 4.03 4.05 3.96 T -C18:1 0 0.07 0.05 0 0 C18:1 23.80 24.85 24.83 24.7 24.74 Iso-C18:1 1.75 1.25 1.18 1.27 1.29 T-C18:2 0.25 0.34 0.30 0.33 0.34 C18:2 58.00 55.56 55.54 55.53 55.55 C20:0 0.20 0.30 0.31 0.35 0.31 T-C18:3 0.18 0.24 0.28 0.24 0.25 C18:3 2.42 2.64 2.70 2.677 2.69 Iso-C18:3 0 0 0 0 0 Ga-C18:3 0.10 0.16 0.17 0.161 0.16 C22:0 0.23 0.49 0.52 0.53 0.50 Original oil *: * The oil which haas no treatment Without PET pieces**: The oil which has not beeen in contact withh PET pieces With PET pieeces***: The oil which w has been in contact c with PET pieces p

3.41 0 24.25 1.64 0.25 57.50 0.21 0.20 2.47 0 0.11 0.25

Table 3: Proffile of fatty acids in i canola oil in diff fferent conditions of o storage Storage connditions Original oil 20 days 20 dayys fatty acid Without PET pieces** p With P PET pieces*** 25 45 25 45 C14:0 0.07 0.06 0.06 0.06 0.06 C16:0 5.07 5.02 4.95 5.10 5.09 C16:1 0.19 0.19 0.18 0.18 0.18 C17:0 0.04 0.49 0.049 0.04 0.04 C18:0 2.03 2.06 2.05 2.04 2.03 T -C18:1 0.13 0.126 0.12 0.11 0.12 C18:1 56.01 55.85 55.91 55.61 55.59 Iso-C18:1 3.47 3.45 3.27 3.54 3.54 T-C18:2 0.10 0.10 0.10 0.10 0.11 C18:2 20.94 20.85 20.84 21.06 21.10 C20:0 0.55 0.57 0 0.57 0.57 T-C18:3 0.56 0.6 0.60 0.60 0.58 C18:3 9.15 9.16 9.17 9.17 9.23 Iso-C18:3 0.05 0.04 0.05 0.06 0.05 Ga-C18:3 1.09 1.18 1.20 1.17 1.16 C22:0 0.29 0.29 0.30 0.30 0.31 Original oil *: * The oil which haas no treatment Without PET pieces**: The oil which has not beeen in contact withh PET pieces With PET pieeces***: The oil which w has been in contact c with PET pieces p

15.14 14.51 14.04 12.81 15.74 15

18

9.28

8

4.04 0.12 24.79 1.25 0.34 55.54 0.31 0.243 2.68 0 0.16 0.52

4.06 0.05 24.86 1.20 0.30 55.56 0.31 0.24 2.67 0 0.17 0.53

60 days Without PET pieces

ys 60 day With PET P pieces

25 0.06 4.92 0.17 0.03 1.86 0.10 55.59 4.10 0.07 21.22 0.45 0.52 9.05 0.04 0.99 0.17

25 0.06 5.06 0.18 0.04 2.04 0.12 56.08 3.50 0.10 20.82 0.57 0.57 9.07 0.05 1.09 0.30

455 0.06 4.85 0.17 0.03 1.74 0.09 566.07 4.21 0.07 211.33 0.43 0.51 9.06 0.03 0.97 0.15

45 0.06 5.00 0.17 0 2.08 0.12 55.85 3.39 0.10 20.87 0.58 0.59 9.16 0.05 1.20 0.30

25°C foor 20 days with plaastic pieces

11.4 11 4

10

6.95 6.89 9.61 8.61 8.53 7.56 9.61 8.22

12

8.5 8.1 11.21 11 21 9.93 9.13 8.8

14

11.74 10.97

induction period(h)

16

3.28 0 244.55 1.47 0.15 577.93 0.17 0 2.32 0 0 0.18

6

25°C foor 20 days withoutt plastic pieces 25°C foor 60 days with plaastic pieces 25°C foor 60 days withoutt plastic pieces 45°C foor 20 days with plaastic pieces 45°C foor 20 days withoutt plastic pieces 45°C foor 60 days with plaastic pieces

4 2 0 Sunflowerr oil

Mix xed oil

Canola oil

45°C foor 60 days withoutt plastic pieces

wer, blended (M Mixed) and canola oils durinng different storrage conditions Fig. 1: Thee induction perriods of sunflow


ues of sunfloweer, blended (Miixed) and canoola oils during ddifferent storagge conditions Fig. 2:Thee peroxide valu

Fig. 3: Thee iodine valuess of sunflower, blended (Mixeed) and canolaa oils during diffferent storage conditions

Fig. 4:Thee amount of free fatty acids off sunflower, bllended (Mixed)) and canola oiils during diffeerent storage connditions n: Conclusion p qualityy On thee examination of fatty acid profile, factors su uch as free faatty acids, peeroxide value,, induction period and iodine i value, some resultss

clearly emerged. Inccreasing storaage period annd temperatture and preseence of PET pieces p has som me effects on o FFA%, PV, induction peeriod and Iodinne value. Itt is concludeed from this study that thhe stability of vegetable ooils is dependen nt on the type of

700 Adv. Environ. Biol., 6(2): 694-701, 2012

oil and its initial physical and chemical properties, time and temperature of storage and the type of packaging (PET and Glass). In addition increasing storage temperature and time accelerated the deterioration and limited the stability of vegetable oils. Results show the quality of oil has been decreased after the storage at high temperature (45°C) and long time of storage. So for preventing of deterioration, the oils which were packed in PET bottles should be stored at a temperature lower than 25°C. If the temperature is raised (T