Perbandingan kestabilan terhadap pengoksidanan ke atas kerepek pisang yang digoreng dalam minyak kelapa sawit olein yang mengandungi antioksidan, tertiary"butylhydroquinone, dan minyak kelapa sawit olein tanpa antioksidan telah dikaji. Nilai-nilai peroksid d{m anisidin bagi minyak yang diekstrak dan kerepek yang disimpan pada suhu 60° C menjelaskan kerepek pisang yang digoreng dalam minyak mengandungi

tertiarybu tylhydroquinone memperolehi kestabilan yang lebih baik terhadap jangkamasa penyimpanan

bagi kerepek tersebu

Augustin, M. A.

Rasit, Rabaiah

Universiti Putra Malaysia Institutional Repository

Pertanika 5(1),119-122 (1982)COMMUNICATION (III)Effect of Tertiarybutylhydroquinone on the stability of fried bananachips .RINGKASANPerbandingan kestabilan terhadap pengoksidanan ke atas kerepek pisang yang digoreng dalamminyak kelapa sawit olein yang mengandungi antioksidan, tertiary"butylhydroquinone, dan minyak kelapasawit olein tanpa antioksidan telah dikaji. Nilai-nilai peroksid d{m anisidin bagi minyak yang diekstrak dankerepek yang disimpan pada suhu 60° C menjelaskan kerepek pisang yang digoreng dalam minyak mengan-dungi tertiarybu tylhydroquinone memperolehi kestabilan yang lebih baik terhadap jangkamasa penyimpananbagi kerepek tersebut.INTRODUCTIONThe stability of oil and fat-containing food isdependent to a large extent on the degree ofoxidative deterioration of the oil in the product(Sherwin and Thompson, 1967; Konstance etal.,1978). In addition, the quality of deep-fried snackfoods and their shelf-life stability differs with thetype of frying medium (Evans and Shaw, 1968;Robertson and Morrison, 1978) and the food usedin the preparation of the product. Antioxidantshave been added to frying media to improve theshelf-life of deep-fried snack food products(Stuckey, 1968). However, the choice of anti-oxidant depends on the type of fat used (Stuckey,1968) because the effectiveness of an antioxidantin inhibiting the oxidative deterioration of the oilis different in different oils (Sherwin andLuckadoo, 1970). Despite the obvious importanceof the stability of deep fried products uponstorage, there has been limited work in this area(Robertson and Morrison, 1972; Fritsch et al.,1975). In this study, the stability was comparedfor banana chips fried in refined, bleached anddeodorised palm olein (RBD olein) with and with-out the antioxidant tertiarybutylhydroquinone(TBHQ). RBD olein was chosen as the frying me-dium because it is the major type of cooking oilused in Malaysia. The antioxidant, TBHQ, hasbeen previously shown to be an effective anti-oxidant for RBD olein (Augustin and Berry,~982). Bananas were used in view of the rapidlyincreasing popularity of banana chips as a Malaysiansnack food.The peroxide and anisidine values of the oilextracted from the banana chips were used asindicators of the stability of the banana chips.The peroxide and anisidine values are measuresof the degree of primary and secondary oxidationof the oil respectively and they relate to organo-leptic and flavour scores of oils (Frioriti et al.,1974; Gray 1978).MATERIALS AND METHODSRefined, bleached and deodorized palm oleinwas obtained from a local refinery. It had beenfractioned using the Lipofrac Process of fractiona-tion on refined palm oil. The oil was used withinone week of being fractionated.The antioxidant tertiarybutylhydroquinone ofanalytical grade was obtained from Supelco Inc.Bellfonte, PA, USA. The bananas (Musa paradisiaca,Linn.), pisang nangka variety, were obtained fromthe local market. Slightly under-ripe bananas wereused as this is the usual practice in the preparationof fried banana chips.Addition of AntioxidantTBHQ at a level of 200 ppm was addeddirectly to RBD olein before the frying operation.The oil was stirred at 60° C for one hour to ensurecomplete dissolution ot: the antioxidant in the oil.Preparation of Banana ChipsBanana rounds of 1.5 mm thickness were cutusing a mechanical slicer. The banana rounds were.soaked in 2% salt brine solution for 30 mins priorto frying.The banana chips were fried in a staihlesssteel thermostated deep-fryer (Model HamiltonDe Lux) containing RBD olein (5 kg) heated to190° C. A batch of 3.0 kg of banana rounds wereplaced in the frying basket and the rounds were119R. RABAIAH AND M.A. AUGUSTINadded TBHQ was used as the frying medium. Theoxidation state of the oil extracted from the chipsmay be attributed to an interplay of the carry-through effect of the antioxidant and the degreeof oxidation of the oil absorbed by the chips. Inthis study it was noted that the oil extracted fromchips immediately after frying had a lower state ofoxidation when the chips were fried in RBD oleincontaining TBHQ (Peroxide value 2.0 ± 0.1 meq/kg, anisidine value 2.9 ± 1). The correspondingvalues for the peroxide and anisidine values of theoil extracted from chips fried in RBD olein with-out antioxidants were 4.7 ± 0.2 meq/kg, and5.2 ± 0.2 respectively. The lower initial state ofoxidation of the oil extracted from chips fried inoil containing TBHQ renders it less susceptible tofurther oxidative deterioration during storage. Thisis in agreement with the observation that thesusceptibility of an oil to oxidative degradation isdependent, among other factors, on the initialoxidation state of the oil (Sherwin, 1978). It istherefore apparent that the role of TBHQ inimproving the stability of the chips stems in partfrom its protective action on the oxidation ofRBD olein during the deep-frying process. It hasbeen suggested previously that an important use ofan an tioxidant in frying operations is to protectthe fat from oxidation during the short period ofexposure of the oil to the high temperatures usedfor frying (Stuckey, 1968). Evidence of this pro-tective effect of the antioxidant during frying i~fried for 10 mins. The temperature drop duringfrying was 10° C. The chips were allowed to drainfor 20 sec, after which the chips were dabbed withtissue paper for 60 sec to remove excess oil. Thechips were packed in 125 ml stoppered brownglass bottles and stored in a convection oven at60° C for 5 weeks. The chips were removed fromthe oven for evaluation at weekly intervals. Therewere enough bottles stored so that a bottle ofchips did not have to be reused once it had beenremoved from the oven. A batch of chips was alsokept at room temperature (- 25° C) for testing atthe end of 5 weeks.Physical and Chemical AnalysesThe moisture and oil contents of the bananarounds and chips were determined according toAOAC 1975 Methods. Peroxide and iodine valuesof the oil were determined in accordance with theAOCS Official Methods (1974). The IUPACMethods of (Paquot, 1979) were used for thedetermination of anisidine and acid values. Allanalyses were carried out in triplicate. The errorsquoted are the mean errors in the analyses.RESULTS AND DISCUSSIONCharacteristics of Oil and Banana ChipsThe RBD olein used for frying experimentshad an acid value of 0.17 ± 0.03 and an iodinevalue of 58.3 ± 0.2. The peroxide and anisidinevalues of the fresh olein were 1.1 ± 0.1 meq/kgand 4.7 ± 0.2 respectively. After frying of thebanana chips, the peroxide value of the used oilwithout antioxidants had increased to 4.6 ± 0.3meq/kg while its anisidine value was 5.2 ± 0.2. Theused oil with added TBHQ had peroxide andanisidine values of 2.0 ± 0.1 meq/kg and 2.9 ± 0.2respectively. The banana chips had a moisturecontent of 2.5%. The oil content of the bananarounds before frying was 0.5% and rose to 17.5%in the deep-fried banana chips.Evaluation of the Stability of Banana ChipsThe peroxide and anisidine values of the oilextracted from banana chips fried in RBD oleinincreased steadily over the 5-week storage period.This showed that the quality of the banana chipsdeteriorated on storage at 60° C as expected. It wasobserved that the oil extracted from the chipsfried in RBD olein containing TBHQ attainedlower peroxide and anisidine values than thatobtained from chips fried in RBD olein withoutantioxidants (Figures 1 and 2). The degree ofoxidative deterioration of the oil extracted fromthe chips, as indicated by the peroxide andanisidine values, showed that the stability ofbanana chips was improved when RBD olein with12060.. 5000-""0-wE 40UoJ'~-J«>UoJ0~oc:UoJ~Fig. 1.DAYS OF STORAGEPeroxide values of oil extracted frombanana chips stored at 60° C; (Chips fricdin RBD olein; .-without anti-oxidants,O-with 200 ppm TBHQ).EFFECT OF TERTIARY BUTY LHYDROQUINONE ON THE STABILITY OF FRIED BANANA CHIPS20w 16:::>...J«>w 12Z0<fl 8Z«4o 5 10 15 20 25 30This study has revealed that the shelf-life ofdeep-fried banana chips can be improved by theaddition of the antioxidant TBHQ to RBD oleinprior to the frying operation. It is to be noted,however, that TBHQ is not currently a permittedadditive to foods in Malaysia, although its use forsuch purposes was approved in the United Statesin 1972. In the absence of legislative approval forTBHQ in Malaysia, it appears necessary to assessother permitted antioxidants and their effective-ness in improving the shelf-life of banana chips.ACKNOWLEDGEMENTThe authors wish to thank Dr. S.K. Berry forhis comments and suggestions.DAYS OF STORAGEFig. 2. Anisidine values of oil extracted frombanana chips stored at 60°C; (Chips friedin RBD olein: .-without antioxidants, 0-with 200 ppm TBHQ).confirmed by the lower oxidation values of theused RBD olein containing TBHQ.The role of the carry-through effect of anantioxidant in imparting improved stability tothe banana chips cannot be disregarded. Thedegree of carry-through effect is related to theamount of antioxidant which has been transferredfrom the oil to the banana chips during frying.Although the concentration of antioxidant in thebanana chips was not examined in this study, theobservation that the protection afforded by TBHQduring storage was less in banana chips than infresh RBD olein (Augustin and Berry, 1982)indicates that there is an incomplete carry-throughof TBHQ during frying. In addition, it has beenreported that under frying conditions phenolicantioxidants are destroyed (Luckadoo andSherwin, 1972; Lin etal., 1979).Although the study was carried out underaccelerated conditions (60° C), the validity of theresults is supported by an evaluation of the chipsstored at room temperature. At the end of 5 weeksstorage at room temperature, the chip~ fried inRBD olein containing TBHQ (PeroxIde value2.6 ± 0.2 meqjkg, anisidine value 4.3 ± 0.2) alsoshowed improved stability over chips fried in oilwithout antioxidants (Peroxide value 6.2 ± 0.2meqjkg, anisidine value 7.7 ± 0.2). As expected,the state of oxidation of the oil extracted from thechips stored at room temperature was lower thanthat obtained froin chips stored at 60° C for thesame period.Rabaiah RasitandM.A. AugustinFaculty ofFood Science and Technology,Universiti Pertanian Malaysia,Serdang, Selangor.REFERENCESA.O.C.S. (1974): Official and Tentative Methods of theAmerican Oil Chemists' Society (3rd ed.,). MethodsCd 8-53 and Cd 1-25.A.O.A.C. (1975): Official Methods of Analysis. (12th ed.).Washington, D.C., U.S.A.AUGUSTIN, M.A., and BERRY, S.K. (1982): unpublishedresults.EVANS, C.D., and SHAW, R. (1968): Flavor and oxida-tive stability of sunflower OIl. The Proceedings ofthe Third International Sunflower Conference,Crookston, MN. Aug. 13-15, pg. 101.FRIORITI, J.A., KANUK, M.J., and SIMS, R.J. (1974):Chemical and Organoleptic Properties of OxidizedFats.JADCS, 51,219-223.FRITSCH, C.W., WEISS, V.E., and ANDERSON, R.H.(1975): Effect of Antioxidants on Refined PalmOil.JADCS. 52,517-519.GRAY, J.1. (1978): Measurement of Lipid Oxidation:A Review.JADCS. 55,539-546.KONSTANCE, R.P., SULLIVAN, J.F., TALLEY, F.B.,CALHOUN, M.J., and CRAIG JR., J.C. (1978):Flavor and Storage stability of explosion-puffedpotatoes: Autoxidation. J. Food Sci. 43,411-414.LIN, F.S., WARNER, C.R., and FAZIO, T. (1979):Decomposition of antioxidants in frying oil.Abstracts of papers. Arner, Chern. Soc., 178(1),AGFD 71.LUCKADOO, B.M., and SHERWIN, E.R. (1972): TertiaryButylhydroquinone as Antioxidant for CrudeSunflower Seed Oil. JADCS. 49,95-97.121R. RABAIAH AND M.A. AUGUSTINPAQUOT, C. (1979): Standard Methods for the Analysisof Oils, Fats and Derivatives, IUPAC, App. Chern.Div., Commission on Oils Fats and Derivatives (6thed.).ROBERTSON, I.A., and MORRISON, W.H. (1978):Flavor and Chemical Evaluation of potato chips friedin sunflower, cottonseed and palm oils. J Food Sci.,43,420-423.SHERWIN, E.R. (1978): Oxidation and Antioxidants inFat and Oil Processing. JADeS, 55,809-814.SHERWIN, E.R. and LUCKADOO, B.M. (1970): Studieson Antioxidant Treatments of Crude Vegetable Oils.JADes. 47,19-23.SHERWIN, E.R., and THOMPSON, I.W. (967): Tertiary-Butylhydroquinone - An Antioxidant for rats andOils and Fat-Containing Foods. Food Tech. 21,912-916.STUCKEY, B.N. (968): Antioxidants as Food Stabilizers.In "Handbook of Food Additives," Furia, T.E. (Ed.)The Chemical Rubber Company.(Received 22 February 1982)122

Effect of Tertiarybutylhydroquinone on the stability of fried banana chips

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Effect of Tertiarybutylhydroquinone on the stability of fried banana chips

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