PaPer 298 Ital. J. Food Sci., vol. 27 - 2015 - Keywords: chicken burger, inulin, quality, vegetable oil, wheat fiber - QUALITY CHARACTERISTICS OF CHICKEN BURGERS ENRICHED WITH VEGETABLE OILS, INULIN AND WHEAT FIBER A. CEGIEŁKAa*, M. CHMIELa, E. KRAJEWSKA-KAMIŃSKAb and E. HAĆ-SZYMAŃCZUKc aWarsaw University of Life Sciences, SGGW, Faculty of Food Sciences, Department of Food Technology, Division of Meat Technology, 159c Nowoursynowska Street, 02-787 Warsaw, Poland bWarsaw University of Life Sciences, SGGW, Analytical Centre, 8 Ciszewskiego Street, 02-786 Warsaw, Poland cWarsaw University of Life Sciences, SGGW, Faculty of Food Sciences, Department of Biotechnology, Microbiology and Food Evaluation, Division of Biotechnology and Microbiology, 159c Nowoursynowska Street, 02-787 Warsaw, Poland *Corresponding author: email: aneta_cegielka@sggw.pl AbstrAct the aim of the study was to modify the composition of chicken burgers in terms of nutritional value by substitution of 20% of pork jowl with a mixture of rapeseed oil and linseed oil, and ad- dition of inulin (1%) or wheat fiber (3%). substitution of pork jowl with vegetable oils resulted in significant increase in polyunsaturated fatty acids, and rosemary extract retarded the oxidation process of lipids. Addition of wheat fiber was helpful in maintaining the thermal processing yield and texture of burgers. Microbiological quality of vacuum packed burgers subjected to 21-day storage at +4°c±1 and -20°c±1 was satisfactory. Ital. J. Food Sci., vol. 27 - 2015 299 IntroductIon despite the constant dissemination of knowl- edge in the field of proper nutrition, consum- ers do not always consider it when choosing foods. results of research over a composition of a daily diet of the average Polish consumer indicated, among others, that the consump- tion structure of fatty acids and the level of in- take of fiber were not consistent with nutrition- al recommendations (dYbKoWsKA et al., 2004; rAdZYMIŃsKA et al., 2005). therefore, in recent years scientists and manufacturers have taken actions towards reformulation of various food products aimed at improving their nutrition- al value (WAsZKoWIAK et. al., 2001; KoWALsKI and PYrcZ, 2009). since meat products provide considerable amounts of fat to the diet (GIVEns et al., 2006), practical strategies of modifying their nutri- tional value include enrichment with polyun- saturated fatty acids (PuFA) (JIMÉnEZ-coL- MEnEro, 2007; PYrcZ et al., 2007; VALEn- cIA et al. 2006; ÖZVurAL and VurAL, 2008). Fatty acid (FA) composition of meat products may be changed by introducing of vegeta- ble or fish oil into the composition of formu- la or by replacing some animal fatty raw ma- terial with vegetable oil. However, the substi- tution of the animal fatty raw material with vegetable oil may have negative effect on the technological quality and sensory desirabili- ty of the product, among others, the increase of thermal loss, the acceleration of fatty acid oxidation process (nItscH, 2007; AndrÉs et al., 2009; dEcKEr and PArK, 2010). In order to prevent adverse changes in quality of meat products prepared with vegetable oil, addition of other ingredients of natural origin may be applied. Potential deterioration of structure or sensory attributes of such products could be avoided by using both vegetable oil and fiber preparation (VurAL et al., 2004; JAVIdIPour et al., 2005). the effective method for retarda- tion of the FA oxidation of meat products en- riched with unsaturated fatty acids is the ad- dition of antioxidants of natural origin, such as plant extracts (GEorGAntELIs et al., 2007; ForELL et al., 2010). recently, ready-to-eat meat products have grown in popularity with Polish consumers (stAnGIErsKI and KIJoWsKI, 2002; GÓrsKA- WArsEWIcZ, 2007). therefore, the main ob- jective of the present study was to develop a popular in Poland ready-to-eat meat product, which is chicken burger, with improved nutri- tional value. Launching such a product into market would facilitate composing a quotidian diet without necessity of changing eating hab- its or giving up favourite meals. this work in- cludes determination of the effect of 20% sub- stitution of pork jowl with a mixture of vegeta- ble oils (rapeseed oil and linseed oil in mass ra- tio 7 to 3) and addition of inulin (1%) or wheat fiber (3%) on physical, chemical, and microbi- ological of chicken burgers. MAtErIALs And MEtHods Materials raw materials: chilled chicken thigh meat and pork jowl, were collected from the local meat processing plant (Karczew near Warsaw, Poland). Pork jowl (about 10 kg) was purchased once, then coarse ground in a laboratory grind- er Mesko Wn60 (Mesko, skarżysko-Kamienna, Poland) equipped with a plate with three kid- ney-shaped orifices. the ground jowl was divid- ed into four lots, which were vacuum packed and stored at -20°c±1 until further use. chick- en meat (about 4 kg) was purchased prior to the each replication of experiment. Fiber preparations were obtained from the manufacturers: inulin orafti® HPX from be- neo-orafti Ltd. (tienen, belgium) and wheat fib- er Vitacel WF400® from J. rettenmeier & söhne GmbH + co. (rosenberg, Germany). cold pressed unrefined vegetable oils: rapeseed oil and lin- seed oil, and spices were obtained from the lo- cal supermarket. About 24 h prior to the production of chick- en burgers, inulin gel was prepared: 1 part of inulin powder was dissolved in 3 parts of water using an electric blender braun Multiquick 7 (braun GmbH, Kronberg, Germany). the solu- tion was heated to boiling. Heating was contin- ued until a clear solution was obtained. the in- ulin solution was chilled at the room tempera- ture for 60 min, then placed in a laboratory re- frigerator (4°c±1). A mixture of vegetable oils was used in the production process of burgers in the form of an emulsion with soy protein. the emulsion was prepared directly before the onset of pro- duction of burgers. rapeseed oil and linseed oil were used in a mass ratio 7 to 3, to prepare the mixture of oils. soy protein isolate sPI 733 (solae ™, st. Louis, Mo, usA) was rehydrated (1 part of dry preparation: 4 parts of water) using water provided in the composition of formula. to obtain the emulsion the mixture of oils was mixed with hydrated soy protein using the elec- tric blender (braun Multiquick 7) at low speed. the mass ratio of oils, rapeseed and linseed oil, was adopted on the basis of literature data on the nutritional properties of oils and the appli- cability of them as ingredients in meat prepa- rations, as well as own calculation (KunAcHo- WIcZ et al., 2005; MIŃKoWsKI et al., 2010). the calculation suggested that the content of poly- unsaturated fatty acids (PuFA) in chicken burg- ers, as a result of modification of the recipe com- position, should not be less than 1.5 g per 100 g of product. 300 Ital. J. Food Sci., vol. 27 - 2015 Fig. 1 - thiobarbituric acid reactive substances (tbArs) values of chicken burgers formulated with different combinations of pork jowl, vegetable oils and dietary fiber preparations, during 21 days of storage at +4°c±1 (a) and at -20°c±1 (b). For product description see table 1. a-cMeans in the same figure (a, b) without a common lowercase letter differ significantly (p < 0.05) – influence of recipe com- position of burgers (product formula) on tbArs value of burgers stored in different periods. A-dMeans in the same figure (a, b) without a common lowercase letter differ significantly (p < 0.05) – influence of storage time on tbArs value of burgers of each formula. table 1 - composition of chicken burgers containing different combinations of pork jowl, vegetable oils, and dietary fiber preparation. Ingredient Product formulaa PC PO POI POW Chicken thigh meat (%) 85.0 85.0 85.0 85.0 Pork jowl (%) 15.0 12.0 12.0 12.0 Mixture of rapeseed and linseed oil (%) - 3.0 3.0 3.0 Total raw materials (%) 100.0 100.0 100.0 100.0 Waterb (%) 10.0 10.0 10.0 10.0 Sodium chloridec (%) 1.8 1.8 1.8 1.8 Soy protein isolatec (%) 1.5 1.5 1.5 1.5 Black pepperc (%) 0.3 0.3 0.3 0.3 Rosemary extractc (%) - 0.03 0.03 0.03 Inulinc (%) - - 1.0 - Wheat fiberc (%) - - - 3.0 aProduct formula: PC - control burgers; PO, - burgers formulated with substitution of 20% of pork jowl by mixture of vegetable oils; POI - burgers formulated with substitution of 20% of pork jowl by mixture of vegetable oils, and added inulin; POW - burgers formulated with substitution of 20% of pork jowl by mixture of vegetable oils, and added wheat fiber. bIn re- lation to the mass of chicken meat and pork jowl (total raw materials). cIn relation to the mass of chicken meat, pork jowl and water. Ital. J. Food Sci., vol. 27 - 2015 301 Chicken burger preparation Four formulas of chicken burgers with dif- ferent combinations of pork jowl, vegetable oils, and dietary fiber preparation (Pc, Po, PoI, PoW) were prepared (table 1). the level of substitu- tion of pork jowl with the mixture of vegetable oils and the addition level of inulin or wheat fib- er were adopted on the basis of previous stud- ies results (cEGIEŁKA and PĘcZKoWsKA, 2008; cEGIEŁKA, 2011). before the production of burgers, pork jowl was thawed (4°c±1, 12 h). chicken meat and pork jowl were ground using a laboratory grind- er Mesko Wn60 equipped with a plate having 5 mm diameter orifices. Meat batters were pre- pared in laboratory mixers Kenwood KM 070 (Kenwood Ltd., Havant, England). After mixing of chicken meat with nacl (about 5 min) fatty raw materials were added: pork jowl only (Pc) or pork jowl and emulsion of oils with soy pro- tein isolate (Po, PoI, PoW). rosemary extract Flavour Guard P GIn:601331 (chr. Hansen A/s, Hørsholm, denmark) was added to bat- ters containing oils. After the next 5 min, oth- er ingredients were added: black pepper, hy- drated soy protein isolate (Pc), and – depend- ing on the product formula – inulin gel (PoI) or wheat fiber (PoW). Mixing was continued un- til a homogenous distribution of all the ingre- dients was obtained (about 10 min). burgers (100 g±1) were formed using a ham- burger mould (about 10.0 cm diameter and 1.0 cm high) and placed in laboratory refrigera- tor (-28°c±2) for 30 min, in order to maintain the shape. burgers were cooked in a commer- cial electric grill (unox s.p.A., Vigodarzere-Pa- dova, Italy) preheated to reach the temperature of 200°c. cooking was continued until the in- ternal temperature of burger reached 72°c. the temperature of burgers was monitored using a portable skewer digital thermometer HI 98804 (Hanna Instruments, Woonsocket, rI, usA). the burgers were then cooled at room temperature (about 30 min) over absorbent paper. After cooling, chicken burgers of each formu- la were divided into two lots: the first one was left in the refrigerator at 4°c±1 until next day (about 24 h), and the second one was devoted to storage research. the procedure was replicated four times. Storage conditions before the storage chicken burgers of each formula were vacuum packed in bags in lots of four and then stored at +4°c±1 and -20°c±1 for a maximum of 21 days. Yield after thermal processing Yield after thermal processing of chicken burg- ers was determined by weight, after cooking and chilling the products to about 4°c, in relation to the weight of raw burgers. Chemical analysis chemical analyzes were carried out on cooked and chilled (4°c±1, 24 h) chicken burgers. content of moisture, protein, total fat, salt, and ash was determined using analytical tech- niques according to AoAc (1990). All analyzes were done in 2 replications. Analysis of texture Measurements of texture were conducted on cooked and chilled (4°c±1, 24 h) chicken burg- ers. the measurements were taken using the universal testing machine Zwicki 1120 (Zwick GmbH & co., ulm, Germany) equipped with the Warner-bratzler blade. shear force (n), the max- imum value of the force registered during move- ment of the blade through the sample, was es- timated at the speed of cross-head of 50 mm/ min. burger samples were prepared by cutting the products into cuboid-shaped pieces (9 mm high, 30 mm wide and 90 mm long). Five repli- cates were measured from five burger samples of each formula. Fatty acid composition Fatty acid (FA) composition was determined in cooked and chilled (4°c±1, 24 h) chicken burg- ers and in chicken burgers stored at +4°c±1 and -20°c±1 for 21 days. to determine the contents of FA the lipid ex- tracts of the burgers were analyzed by gas chro- matography. Procedure proposed by FoLcH et al. (1957) was used for lipid extraction from the sample. Fatty acid methyl esters (FAME) were obtained according to method of MorrI- son and sMItH (1964). chromatographic ana- lyzes of FAME were performed using an Agilent 7890A Gc system gas chromatograph (Agilent technologies, santa clara, cA, usA) equipped with a split-spiltless injector and a flame ioniza- tion detector, using a fused silica capillary col- umn rt®-2330 (0.25 mm internal diameter and 105 m long; restek corp., bellefonte, PA, usA). the mobile phase consisted of helium at a flow of 1.2 mL/min. the FAMEs were identified by comparing their retention times with FAMEs of the reference standards (supleco 37 compo- nent Fame Mix; sigma-Aldrich, st. Louis, Mo, usA). Quantification of FA was done by deter- mining the surface areas of their peaks. All an- alyzes were done in 2 duplicates. Lipid oxidation Lipid oxidation was assessed in cooked and chilled (4°c±1, 24 h) chicken burgers and in chicken burgers stored at +4°c±1 and -20°c±1 302 Ital. J. Food Sci., vol. 27 - 2015 for 7, 14 and 21 days. the 2-thiobarbituric acid (tbA) test was carried out in each sample in du- plicate. thiobarbituric acid reactive substances (tbArs) values were determined by an extrac- tion method according to the procedure of sHA- HIdI (1990). A constant coefficient of 2.34 was employed for converting the absorbance units to tbArs values, which were expressed as mg malondialdehyde/kg sample (mg MAd/kg). Microbiological analysis Microbiological analyzes were carried out in cooked and chilled (4°c±1, 24 h) chicken burg- ers and in chicken burgers stored at +4°c±1 and -20°c±1 for 7, 14 and 21 days. the analyzes were conducted in Analytical center of Warsaw university of Life sciences - sGGW (Warsaw, Poland) in conditions accord- ant to requirements of Pn-En Iso 7218:2008 standard (Pcs, 2008). the microbiological cul- ture media were prepared according to PKn-cEn Iso/ts 11133-1:2009 standard (Pcs, 2009). the preparation of test samples for microbiolog- ical analyzes, initial suspension and decimal di- lutions was carried out according to Pn-En Iso 6887-2:2005 (Pcs, 2005b). For quantitative an- alyzes, 10 g of the sample from central part of burger was collected. next, the first decimal di- lution was performed by dosing physiological solution with peptone according to Pn-En Iso 6887-1:2000 (Pcs, 2000). determination of to- tal bacteria count (tbc) was conducted accord- ing to Pn-En Iso 4833:2004+Ap1:2005 standard (Pcs, 2005a) using PcA culture medium (Plate count Agar) of bio-rad company (bio-rad Lab- oratories, Inc., Herkules, cA, usA). determina- tion of coliform bacteria was conducted accord- ing to Pn-Iso 8432:2007 standard (Pcs, 2007) using VrbL medium (Violet red bile Lactose Agar; bio-rad) and bGbbL (bile Green brilliant Lactose broth; bio-rad). the presence of Sal- monella ssp. in 25 g of product was determined according to Pn-En Iso 6579:2003 standard (Pcs, 2003) using MKttn selective media (Mül- ler-Kauffman’s medium with tetrathionate and novobiocin), rVs (medium acc. to rappaport- Vassilliads with soya), XLd (xylose lysine deox- ycholate) and Hektoen of bio-rad company. the colonies typical for Salmonella ssp. and suspi- cious colonies were confirmed using API 20E bi- ochemical tests of bioMérieux company (bioMé- rieux sp. z o.o., Warsaw, Poland). Statistical analyses Microbiological data was analyzed using sta- tistica 6.0 (statsoft Inc., tulsa, okla., u.s.A.). All the other data was analyzed using statgraph- ics Plus 4.1. (stsc Inc., rocville, Md, u.s.A.) by means of the one-way AnoVA test. differ- ences between burger formulas were tested by the tukey Hsd test. Pearson’s correlation coef- ficients (r) were calculated to determine the lin- ear correlation between chosen quality attrib- utes of chicken burgers. rEsuLts And dIscussIon Yield after thermal processing, chemical composition and texture Yield after thermal processing of chicken burg- ers ranged from 82.0 to 88.4% and was not af- fected (p > 0.05) by applied modifications of the composition of formula (table 2). the results obtained in this study are in agree- ment with those obtained by AndrÉs et al. (2009) who showed that an introduction of squid oil into the composition of formula of frankfurters instead of beef tallow did not affect thermal loss of the product. PYrcZ et al. (2007), LÓPEZ-LÓPEZ et al. (2009), and YoussEF and bArbut (2011) proved, in turn, that thermal loss of scalded sau- sages increased as the result of replacement of some animal fat with vegetable oil. decrease in processing yield of meat products enriched with table 2 - Processing yield, chemical composition, and shear force of chicken burgers formulated with different combinations of pork jowl, vegetable oils, and dietary fiber preparation. Characteristic Product formula1 PC PO POI POW Processing yield (%) 88.4±3.9a 84.5±3.6a 82.0±2.8a 87.7±4.6a Moisture (%) 62.3±0.2a 62.8±0.7a 62.3±0.1a 62.6±0.6a Protein (%) 18.0±0.5a 18.4±0.6a 18.7±0.1a 18.3±0.1a Fat (%) 14.5±0.6a 13.3±1.7a 13.0±1.3a 13.7±0.8a Chlorides (%) 2.3±0.1a 2.3±0.1a 2.2±0.1a 2.3±0.1a Ash (%) 2.7±0.1a 2.7±0.2a 2.7±0.2a 2.8±0.2a Shear force (N) 31.1±2.6b 23.7±1.6a 21.9±2.5a 29.9±1.1b 1Product formula: see Table 1. a, bMeans within a raw without a common lowercase letter differ significantly (p < 0.05). Ital. J. Food Sci., vol. 27 - 2015 303 oil may be counteracted - like in this study - by an application of oil in form of an emulsion with hydrated vegetable protein (YoussEF and bAr- but, 2011) or combined addition of oil and fib- er preparation (VurAL et al., 2004; JAVIdIPour et al., 2005). chemical composition of chicken burgers for- mulated with different combinations of pork jowl, vegetable oils, and dietary fiber prepara- tion is shown in table 2. the content of any of the analyzed chemical component of burgers was not differentiated significantly (p > 0.05) by the applied modifications the composition of for- mula. slightly lower fat content in burgers pre- pared with a contribution of vegetable oils (Po, PoI, PoW), when compared to control product (Pc), could have been caused by poorer oil main- tenance in protein matrix of the product, and as a consequence its loss during thermal treatment. the results obtained in this study are in agreement with those presented by KAYAArdI and GÖK (2003), MuGuErZA et al. (2003), PEL- sEr et al. (2007) and cÁcErEs et al. (2008) who also showed that replacement of some animal fatty raw material with oil did not exert any in- fluence on the chemical composition of scald- ed sausages and raw fermented sausages. In contrast, GArMIEnE et al. (2007), and LÓPEZ- LÓPEZ et al. (2009) found in studies on frank- furters and scalded sausages, respectively, that substitution of some animal fatty raw material with oil resulted in a significant increase in wa- ter content and decrease in protein content in these meat products. Enrichment of ready-to-eat meat prod- ucts with wheat fiber: beef burgers (cEGIEŁKA and bondErsKI, 2010) and poultry burgers (cEGIEŁKA and PĘcZKoWsKA, 2008), did not differentiate the chemical composition of these products when compared to their counterparts prepared without the fiber. It was also shown that the application of inulin did not affect the chemical composition of turkey meat balls (ErGÖnÜL et al., 2009). Mean values of shear force measured in chick- en burgers ranged from 21.9 n to 31.1 n (ta- ble 2). Measurements of shear force of chicken burgers revealed that the texture of products was impacted (p < 0.05) by the applied modifi- cations the composition of formula (table 2). It was found that substitution of 20% of pork jowl with vegetable oils (Po) or application of both oils and inulin (PoI) resulted in a significant (p < 0.05) decrease of shear force when compared to the control product (Pc). the product enriched with oils and wheat fiber (PoW) was character- ized by a comparable (p > 0.05) shear force to the control product (Pc). In contrast to the results of this study, in- strumental measurements of texture of scalded sausages showed that substitution of some ani- mal fat with vegetable oil significantly decreased hardness of these products (AMbrosIAdIs et al., 1996; PYrcZ et al., 2007; ÖZVurAL and VurAL, 2008). However, in studies on raw sausages it was reported that the deterioration of texture of sausages prepared with oil could be counteract- ed by addition of dietary fiber preparation (Vu- rAL et al., 2004; JAVIdIPour et al., 2005). some literature findings suggest that die- tary fiber preparations could help to obtain the desired texture of ready-to-eat meat products. It was found that the addition of wheat fib- er increased the shear force of poultry burgers (cEGIEŁKA and PĘcZKoWsKA, 2008) and beef burgers (cEGIEŁKA and bondErsKI, 2010). In other studies ErGÖnÜL et al. (2009) showed that inulin addition did not affect significantly the in- strumental hardness of turkey meat balls. the above mentioned products, however, did not con- tain vegetable oil in the composition of formula. Fatty acid composition the share of main FA in the overall FA pool of chicken burgers is shown in tables 3, 4 and 5. the results obtained showed that substitution of 20% of pork jowl with a mixture of vegetable oils did not totally changed fatty acid profile of chicken burgers, but improved nutritional value of them in terms of the share of saturated and polyunsaturated fatty acids (sFA and PuFA). Products enriched with vegetable oils, irre- spectively of an addition of fiber preparation (Po, PoI, PoW), contained significantly (p < 0.05) less saturated fatty acids (sFA) than the control prod- uct (Pc; table 3). In burgers of all the formulas, palmitic acid (c16:0) and stearic acid (c18:0) were present in the highest amounts among sFA, and their contents were significantly (p < 0.05) higher in the Pc product when compared to burgers prepared with vegetable oils. Introduc- tion of a mixture of vegetable oils into the compo- sition of formula of chicken burgers did not sig- nificantly (p > 0.05) increase the share of mono- unsaturated fatty acids (MuFA) in the overall FA pool (table 4), but Po, PoI, and PoW products contained significantly (p < 0.05) more PuFA, in- cluding nutritionally valuable PuFA n-3, when compared to the Pc product (table 5). Among MuFA, oleic acid (c18:1 n-9) was predominant is the products of all the formulas. In burgers prepared with oils, significantly lower (p < 0.05) amounts of myristoleic (c14:1) and elaidic acid (c18:1t) were found when compared to the Pc product. the content of polyunsaturated fatty acids (PuFA) in chicken burgers with oils (Po, PoI, PoW) was higher than 2.5 g per 100 g of prod- uct. Irrespectively of the burger formula, the highest share in PuFA pool had linoleic acid (LA; c18:2 n-6). the LA content in burgers was not significantly (p > 0.05) differentiated by appli- cation of vegetable oils. chicken burgers of all the formulas contained relatively high amounts of linolenic (c18:3 n-3), arachidonic (c20:4 n-6) 304 Ital. J. Food Sci., vol. 27 - 2015 table 3 - sFA of chicken burgers (g/100 g total FA) formulated with different combinations of pork jowl, vegetable oils, and dietary fiber preparations, with different storage conditions, during 21 days of storage. FA/FA group Storage conditions Product formula1 PC PO POI POW Capric C10:0 +4°C±1, 24 h 0.081aA 0.070aA 0.046aA 0.062aA +4°C±1, 21 d 0.083aA 0.073aA 0.044aA 0.060aA -20°C±1, 21d 0.079aA 0.066aA 0.041aA 0.076aA Lauric C12:0 +4°C±1, 24 h 0.648aA 0.562aA 0.522aA 0.512aA +4°C±1, 21 d 0.643aA 0.545aA 0.512aA 0.511aA -20°C±1, 21d 0.643aA 0.531aA 0.476aA 0.516aA Myristic C14:0 +4°C±1, 24 h 1.466bA 1.212aA 1.185aA 1.152aA +4°C±1, 21 d 1.367abA 1.218abA 1.188aA 1.154aA -20°C±1, 21d 1.469bA 1.206abA 1.163aA 1.158aA Palmitic C16:0 +4°C±1, 24 h 21.576bA 18.350aA 18.114aA 17.638aA +4°C±1, 21 d 21.740bA 18.550aA 18.244aA 17.868aA -20°C±1, 21d 21.733bA 18.579aA 18.392aA 17.915aA Stearic C18:0 +4°C±1, 24 h 8.633bA 7.352aA 7.351aA 7.023aA +4°C±1, 21 d 8.672bA 7.395aA 7.334aA 7.112aA -20°C±1, 21d 8.656bA 7.537aA 7.604aA 7.256aA Arachidic C20:0 +4°C±1, 24 h 0.130aA 0.179bA 0.179bA 0.193bA +4°C±1, 21 d 0.129aA 0.180bA 0.177bA 0.184bA -20°C±1, 21d 0.129aA 0.181bA 0.182bA 0.195bA Behenic C22:0 +4°C±1, 24 h ND2 0.073aA 0.076aA 0.085aA +4°C±1, 21 d ND2 0.069aA 0.076aA 0.081aA -20°C±1, 21d ND2 0.073aA 0.079aA 0.085aA SFA +4°C±1, 24 h 32.944bA 28.142aA 27.827aA 27.007aA +4°C±1, 21 d 33.128bA 28.378aA 27.930aA 27.315aA -20°C±1, 21d 33.120bA 28.518aA 28.294aA 27.533aA 1Product formula: see Table 1. 2ND - not detected (the content of the FA was lower than 0.05 g/100 g of total FA). abcMeans within a row without a common low- ercase letter differ significantly (p < 0.05) – influence of product formula on FA content in burgers stored in different conditions. AMeans within a column with a common uppercase letter do not differ significantly (p < 0.05) – influence of storage conditions on FA content in burgers of different formula. table 4 - MuFA of chicken burgers (g/100 g total FA) formulated with different combinations of pork jowl, vegetable oils, and dietary fiber preparations, with different storage conditions, during 21 days of storage. FA/FA group Storage conditions Product formula1 PC PO POI POW Myrictoleic C14:1 +4°C±1, 24 h 0.133bA 0.114aA 0.113aA 0.115aA +4°C±1, 21 d 0.132bA 0.108aA 0.112aA 0.114aA -20°C±1, 21d 0.135bA 0.108aA 0.112aA 0.113aA Palmitoleic C16:1 +4°C±1, 24 h 3.456aA 2.874aA 2.824aA 2.876aA +4°C±1, 21 d 4.438bcA 2.860aA 2.800aA 2.853aA -20°C±1, 21d 3.446cA 2.821aA 2.870abA 2.847aA Elaidic C18:1t +4°C±1, 24 h 0.372bA 0.282abA 0.288abA 0.271aA +4°C±1, 21 d 0.542bA 0.311aA 0.325aA 0.305aA -20°C±1, 21d 0.455abA 0.306aA 0.317aA 0.306aA Oleic C18:1 (n-9) +4°C±1, 24 h 40.237abA 40.837abA 39.712aA 42.830bA +4°C±1, 21 d 40.429aA 41.096aA 39.810aA 40.911aA -20°C±1, 21d 40.313aA 40.953aA 39.499aA 40.779aA Eicosanoic C20:1 +4°C±1, 24 h 0.734aA 0.770aA 0.744aA 0.773aA +4°C±1, 21 d 0.731aA 0.774aA 0.741aA 0.779aA -20°C±1, 21d 0.731aA 0.778aA 0.747aA 0.767aA Eruic C22:1 +4°C±1, 24 h 0.054aA 0.084aA 0.055aA 0.061aA +4°C±1, 21 d 0.045bA 0.018aA 0.017aA 0.017aA -20°C±1, 21d 0.038bA 0.019aA 0.039bA 0.019aA MUFA +4°C±1, 24 h 45.959aA 45.960aA 44.720aA 47.926aA +4°C±1, 21 d 48.297aA 48.234aA 46.749aA 48.066aA -20°C±1, 21d 48.143aA 48.113aA 46.544aA 47.705aA 1Product formula: see Table 1. 2ND - not detected (the content of the FA was lower than 0.05 g/100 g of total FA). abcMeans within a row without a common low- ercase letter differ significantly (p < 0.05) – influence of product formula on FA content in burgers stored in different conditions. AMeans within a column with a common uppercase letter do not differ significantly (p < 0.05) – influence of storage conditions on FA content in burgers of different formula. Ital. J. Food Sci., vol. 27 - 2015 305 and eicosatrienoic acid (c20:3 n-3). the signifi- cant (p < 0.05) increase in the share of PuFA in overall FA pool in Po, PoI, and PoW products - when compared to Pc product - was mainly de- termined by an increased content of linolenic acid. the presence of valuable nutritionally long- chain PuFA n-3 acids: eicosapentaenoic (EPA) and docosahexaenoic acid (dHA), was not ob- served in the products prepared with oils. this was possibly due to the fact that the share of vegetable oils in the recipe composition of burg- ers was relatively low. the ratio of PuFA to sFA and the ratio of PuFA n-6 to PuFA n-3 are often used in nutri- tional characteristics of lipids in food. the val- table 5 - PuFA of chicken burgers (g/100 g total FA) formulated with different combinations of pork jowl, vegetable oils, and dietary fiber preparations, with different storage conditions, during 21 days of storage. FA/FA group Storage conditions Product formula1 PC PO POI POW Linoleic C18:2 (n-6) +4oC±1, 24 h 13.341aA 14.939aA 15.508aA 15.555aA +4oC±1, 21 d 13.054aA 14.730aA 15.433aA 15.400aA -20oC±1, 21d 13.274aA 14.700aA 15.403aA 15.515aA γ- Linolenic C18:3 (n-6) +4oC±1, 24 h 0.081aA 0.072aA 0.072aA 0.068aA +4oC±1, 21 d 0.077aA 0.071aA 0.072aA 0.068aA -20oC±1, 21d 0.080aA 0.070aA 0.069aA 0.071aA Linolenic C18:3 (n-3) +4oC±1, 24 h 1.631aA 5.353bA 6.410bA 6.092bA +4oC±1, 21 d 1.599aA 5.248bA 6.480bA 6.932bA -20oC±1, 21d 1.587aA 5.211bA 6.362bA 6.015bA Eicosadienoic C20:2 (n-6) +4oC±1, 24 h 0.327aA 0.291aA 0.275aA 0.280aA +4oC±1, 21 d 0.324aA 0.290aA 0.271aA 0.280aA -20oC±1, 21d 0.324aA 0.296aA 0.289aA 0.285aA Eicosatrienoic C20:3 (n-6) +4oC±1, 24 h 0.110aA 0.103aA 0.101aA 0.098aA +4oC±1, 21 d 0.112aA 0.099aA 0.096aA 0.098aA -20oC±1, 21d 0.114aA 0.104aA 0.104aA 0.101aA Eicosatrienoic C20:3 (n-3) +4oC±1, 24 h 0.158aA 0.155aA 0.134aA 0.140aA +4oC±1, 21 d 0.140aA 0.115aA 0.107aA 0.110aA -20oC±1, 21d 0.124aA 0.115aA 0.106aA 0.107aA Arachidonic C20:4 (n-6) +4oC±1, 24 h 0.198aA 0.212aA 0.202aA 0.195aA +4oC±1, 21 d 0.196aA 0.173aA 0.179aA 0.172aA -20oC±1, 21d 0.216aA 0.226aA 0.218aA 0.179aA Eicosapentaenoic (EPA) C20:5 (n-3) +4oC±1, 24 h ND2 ND2 ND2 ND2 +4oC±1, 21 d ND2 ND2 ND2 ND2 -20oC±1, 21d ND2 ND2 ND2 ND2 Docosahexaenoic (DHA) C22:6 (n-3) +4oC±1, 24 h ND2 ND2 ND2 ND2 +4oC±1, 21 d ND2 ND2 ND2 ND2 -20oC±1, 21d ND2 ND2 ND2 ND2 PUFAs +4oC±1, 24 h 15.862aA 21.125bA 22.701bA 22.427bA +4oC±1, 21 d 15.501aA 20.726bcA 22.639cA 22.058cA -20oC±1, 21d 15.720aA 20.722bcA 22.569cA 22.271cA 1Product formula: see Table 1. 2ND - not detected (the content of the FA was lower than 0.05 g/100 g of total FA). abcMeans within a row without a common low- ercase letter differ significantly (p < 0.05) – influence of product formula on FA content in burgers stored in different conditions. AMeans within a column with a common uppercase letter do not differ significantly (p < 0.05) – influence of storage conditions on FA content in burgers of different formula. ues of these ratios for control burgers (Pc) were 0.48 and 7.91, respectively (table 6). the intro- duction of mixture of vegetable oils into the for- mula composition of burgers resulted in signif- icant (p < 0.05) changes in the value of both ra- tios. For the Po, PoI, and PoW burgers the ra- tios of PuFA to sFA ranged from 0.75 to 0.83, and the ratios of PuFA n-6 to PuFA n-3 varied between 2.47 and 2.84. the significant (p < 0.05) increase in the PuFA to sFA ratio, and decrease in the PuFA n-6 to PuFA n-3 ratio in burgers for- mulated with oils - when compared to the con- trol product - was the positive effect indicating improvement of the nutritional value of fat in these products. 306 Ital. J. Food Sci., vol. 27 - 2015 regardless of the temperature of 21-day stor- age no significant (p > 0.05) changes in the con- tent of any FA were found in any of the burgers. the results obtained confirm the thesis put forward by JIMÉnEZ-coLMEnEro (2007), who - based on the literature data - reported that sub- stitution of some animal fatty raw material with oil was an effective method of improvement of FA composition in a wide range of meat prod- ucts. usefulness of linseed oil and rapeseed oil in improvement to nutritional value of lipids in meat products, expressed by increased contri- bution of uFA and PuFA n-3, was confirmed by GArMIEnE et al. (2007), MAKAŁA and JErZEWs- KA (2008) in scalded sausages, and by PELsEr et al. (2007) in fermented sausages. It has been also found that the FA composition of meat prod- ucts may be modified by the application of ol- ive oil (KAYAArdI and GÖK, 2003), soybean oil (MuGuErZA et al., 2001), or mixture of vegeta- ble oils (ÖZVurAL and VurAL, 2008; LoPÉZ-Lo- PÉZ et al., 2009). Mixture of oils was also used for an improvement in nutritional value of li- pids in ready-to-eat meat products: beef burg- ers (ForELL et al., 2010) and pork patties (LEE et al., 2006). Lipid oxidation changes in tbArs value in chicken burg- ers subjected to storage at the temperature of +4°c±1 and -20°c±1 are presented in Figs. 1a and 2b, respectively. the highest tbArs values were observed in control burgers (Pc), irrespec- tively of the storage temperature and time. sig- nificantly lower (p < 0.05) tbArs values were observed in burgers prepared with vegetable oils (Po, PoI, PoW), which meant inhibition of the oxidation process of lipids when compared to the Pc product. It should be noted that en- richment of burgers with oils was accompanied by addition of rosemary extract, which was in- tended to protect FA against oxidation. the results obtained confirmed that, irrespec- tively of product formula, freezing was better method of storage than refrigerating. Although lowering the temperature of the storage from +4 to -20 degrees did not stop completely the oxi- dation process of FA in burgers, it was inhibit- ed significantly. When compared to the results presented by other authors (FErnÁndEZ-LÓPEZ et al., 2005; PIEtrZAK and MYron, 2008; ForELL et al., 2010), the tbArs values in chicken burgers were relatively low, both after manufacturing (24 h) and 21 days of storage. Incorporation of oil into the formula compo- sition of meat product may influence the oxi- dative stability of lipids in the product. Accord- ing to KAYAArdI and GÖK (2003), the adverse changes of lipids in beef sausage were caused by the partial replacement of beef tallow with olive oil. In turn, MuGuErZA et al. (2003), and PELsEr et al. (2007) reported that replacement of some animal fatty raw material with vegeta- ble oil in fermented sausages did not intensify the adverse changes in lipids, such as oxidation and hydrolysis. MAKAŁA and JErZEWsKA (2008) also found that the quality of frankfurters en- riched with linseed oil, in terms of lipids oxida- tive changes, was satisfactory even after 8-week of refrigerating storage. In order to extend the storage stability of chicken burgers with enriched oils, an anti- table 6 - Proportions of PuFA : sFA and PuFA n-6 : PuFA n-3 in chicken burgers formulated with different combinations of pork jowl, vegetable oils, and dietary fiber preparations, with different storage conditions, during 21 days of storage. FA group Storage conditions Product formula1 PC PO POI POW PUFA n-6 +4°C±1, 24 h 14.056aA 15.617aA 16.157aA 16.196aA +4°C±1, 21 d 13.762aA 15.363aA 16.052aA 16.018aA -20°C±1, 21 d 14.010aA 15.397aA 16.082aA 16.160aA PUFA n-3 +4°C±1, 24 h 1.806aA 5.508bA 6.544bA 6.231bA +4°C±1, 21 d 1.739aA 5.364bA 6.587bA 6.041bA -20°C±1, 21 d 1.711aA 5.362bA 6.487bA 6.122bA PUFA : SFA +4°C±1, 24 h 0.48aA 0.75bA 0.82bA 0.83bA +4°C±1, 21 d 0.47aA 0.73bcA 0.81cA 0.81cA -20°C±1, 21 d 0.48abA 0.73bcA 0.80cA 0.81cA PUFA n-6 : PUFA n-3 +4°C±1, 24 h 7.91bA 2.84aA 2.4747aA 2.60aA +4°C±1, 21 d 7.91bA 2.86aA 2.44aA 2.65aA -20°C±1, 21 d 8.19bA 2.89aA 2.48aA 2.64aA 1Product formula: see Table 1. abcMeans within a row without a common lowercase letter differ significantly (p < 0.05) – influence of product formula on FA con- tent in burgers stored in different conditions. AMeans within a column with a common uppercase letter do not differ significantly (p < 0.05) – influence of storage conditions on FA content in burgers of different formula. Ital. J. Food Sci., vol. 27 - 2015 307 oxidant additive of natural origin, which was rosemary extract, was used. the effectiveness of this component in the inhibition of lipid ox- idation had already been confirmed in studies on ready-to-eat meat products (nIssEn et al., 2004; FErnÁndEZ-LÓPEZ et al., 2005; GEorG- AntELIs et al., 2007; ForELL et al., 2010; KonG et al., 2010). Microbiological analysis the changes in tbc in chicken burgers stored at the temperature of +4°c±1 and -20°c±1 are shown in Figs. 2a and 2b, respectively. It was found that 24 h after preparing, tbc in burgers was as follows: 2.54 log cfu/g for Pc product, 2.73 log cfu/g for PoI product, 2.78 log cfu/g for Po product, and 2.88 log cfu/g for PoW prod- uct, and was not significantly (p < 0.05) differen- tiated by the applied modifications of the com- position of formula. After the 21-day storage at +4oc±1, the tbc increased to the level of: 5.32 log cfu/g for PoI product, 5.61 log cfu/g for PoW product, 7.40 log cfu/g for Po product, and 8.21 log cfu/g for Pc product. the increase of tbc during the whole period of storage was statistically signif- icant (p < 0.05) only in the Pc and Po product. After the 21-day storage at -20oc±1 the tbc increased to the level of: 2.54 log cfu/g for PoI product, 2.65 log cfu/g for PoW product, 2.79 log cfu/g for Po product, and 2.80 log cfu/g for Pc product. the tbc of any of the frozen prod- ucts was not significantly (p < 0.05) differentiat- ed during the whole period of storage. For chick- en burgers of each formula the tbc was signifi- cantly (p < 0.05) higher in the refrigerated prod- uct than in the frozen one after 21 days of stor- age (results not showed). the presence of Salmonella ssp. was not found in chicken burgers, and the number of coliform bacteria was lower than 10 cfu/g during the whole storage period, regardless of the prod- uct formula and storage conditions (tempera- ture and time). the results obtained proved that the microbi- ological quality of chicken burgers of all the four formulas fulfilled the requirements mentioned Fig. 2 - total bacteria count of chicken burgers formulated with different combinations of pork jowl, vegetable oils and die- tary fiber preparations, during 21 days of storage in refrigerator (a) or freezer (b). For product description see table 1. 308 Ital. J. Food Sci., vol. 27 - 2015 in Ec rEGuLAtIon (2007) with respect to Sal- monella ssp. despite the fact that the regulation does not require determination of coliform bacte- ria nor total bacteria count in ready-to-eat meat products from poultry meat, it should be noticed that they may influence both health safety and shelf-life of these products. the results obtained are in agreement with these obtained AndrÉs et al. (2009) who showed that microbiological quality of poultry frankfurt- ers containing squid oil instead of beef tallow was not significantly differentiated when compared to the control product. similarly, LoPÉZ-LoPÉZ et al. (2009), on the basis of determination of total bacte- ria count and lactic bacteria count, found that mi- crobiological quality of pork frankfurters enriched with olive or algae oil did not differ significantly during storage. tbc in frankfurters after manu- facturing ranged - depending on product formu- la - from 2.64 to 4.18 log cfu/g, and was compa- rable to the results obtained in the present study. concLusIons After summarizing the results of this study it was found that 20% substitution of pork jowl with a mixture of vegetable oils in the composi- tion of formula of chicken burgers resulted in an improvement in nutritional quality in terms of FA composition. chicken burgers enriched with oils contained significantly less sFA and more PuFA, including nutritionally valuable PuFA n-3, than the control product, what means the im- provement in nutritional value of lipids in these products. the oxidation process of lipids in prod- ucts containing vegetable oils could be retard- ed significantly by the addition of 0.03% of rose- mary extract. the results of measurements of the shear force of burgers indicated that addition of 3% of wheat fiber to product prepared with the mixture of vegetable oils as the 20% substitute of pork jowl counteracted the changes in texture. Microbiological quality of vacuum-packed burg- ers subjected to 21-day storage at the temper- ature of +4°c±1 and -20°c±1 was satisfactory. AcKnoWLEdGEMEnts this work was financially supported by the Polish Ministry of science and Higher Education in 2009-2011 (grant no n n312 210936). rEFErEncEs Ambrosiadis J., Kyriakos P.V. and Georgakis s.A. 1996. Phys- ical, chemical and sensory characteristics of cooked meat emulsion style products containing vegetable oils. Int. J. Food sci. & technol. 31: 189-194. Andrés s.c., Zaritzky n.E. and califano A.n. 2009. Innova- tions in the development of healthier chicken sausages formulated with different lipid sources. Poultry sci. 88: 1755-1764. AoAc. Association of official Analytical chemists. 1990. of- ficial methods of analysis. (15th Ed.). Washington: AoAc. cáceres E., Garciá M.L. and selgas M.d. 2008. Effect of pre- emulsified fish oil – as source of PuFA n-3 – on microstruc- ture and sensory properties of mortadella, a spanish bo- logna-type sausage. Meat sci. 80: 183-193. cegiełka A. 2011. Wpływ stopnia wymiany podgardla wiepr- zowego mieszaniną olejów roślinnych na jakość burgerów drobiowych. Zeszyty naukowe uniwersytetu Ekonomicz- nego w Poznaniu. 205: 158-166. cegiełka A. and bonderski M. 2010. Wpływ dodatku pre- paratów błonnika pszennego na jakość hamburgerów wołowych. Zeszyty Problemowe Postępów nauk rolnic- zych. 552: 29-37. cegiełka A. and Pęczkowska M. 2008. Wpływ wielkości dodat- ku preparatu błonnika pszennego na jakość hamburger- ów drobiowych. roczniki Instytutu Przemysłu Mięsnego i tłuszczowego. 46(2): 75-82. decker E.A. and Park Y. 2010. Healthier meat products as functional foods. Meat sci. 86: 49-55. dybkowska E., Waszkiewicz-robak b. and Świderski F. 2004. Assessment of n-3 and n-6 polyunsaturated fatty acid in- take in the average Polish diet. Pol. J. Food nut. sci. 13/54 (4): 409-414. Ec. European commission. 2007. commission regulation (Ec) no 1441/2007 of 5 december 2007 amending regu- lation no 2073/2005 on microbial criteria for foodstuffs. official Journal of European union, L322, 1-12. Ergönül b., Ergönül P.G. and obuz E. 2009. Funktionelle Ei- genschaften prebiotischer Zutaten in Fleischprodukten: chemische, physikalische und sensorische Eigenschaften von mit Inulin und oligofruktose hergestellten Hackfleis- chbällchen. Fleischwirtschaft. 89(2): 140-143. Fernández-López J., Zhi n., Aleson-carbonell L., Perez-Alva- rez J.A. and Kuri V. 2009. Antioxidant and antibacteri- al activities of natural extracts: application in meatballs. Meat sci. 69: 371-380. Folch J., Lees M. and stanley G.H.s. 1957. A simple method for the isolation and purification of total lipids from ani- mal tissues. J. biol. chem. 226: 497-509. Forell s.c.P., ranalli n., Zaritzky n.E., Andrés s.c. and cal- ifano A.n. 2010. Effect of type of emusifiers and antioxi- dants on oxidative stability, colour and fatty acid profile of low-fat beef burgers enriched with unsaturated fatty ac- ids. Meat sci. 86: 364-370. Garmiene G., Zaborskiene G., salasaviciene A. and Liutkie- vicius A. 2007. Analyse der bildung von oxidations- und Hydrolyseprodukten: untersuchungen zu oxidations- und Hydrolyseprozessen in Fleischprodukten mit wertvollen Zutaten. Fleischwirtschaft. 87(8): 100-103. Georgantelis d., bekas G., Katikou P., Ambrosiadis I. and Fletouris d. 2007. Effects of rosemary extract, chitosan and α-tocoferol on lipid oxidation and colour stability dur- ing frozen storage of beef burgers. Meat sci. 75: 256-264. Givens d.I., Kliem E. and Gibbs r.A. 2006. the role of meat as a source of n-3 polyunsaturated fatty acids in the hu- man diet. Meat sci. 74: 209-218. Górska-Warsewicz H. 2007. Żywność wygodna w sektorze mięsnym. Przem. spoż. 61(4): 36-38. Javidipour I., Vural H., Özbaş Ö.Ö. and tekin A. 2007. Ef- fects of interesterified vegetable oils and sugar beet fibre on the quality of turkish-type salami. Int. J. Food sci. & technol. 40: 177-185. Jiménez-colmenero F. 2007. Healthier lipid formulation ap- proaches meat-based functional foods: technological op- tions for replacement of meat fats by non-meat fats. trends Food sci. & technol. 18: 567-578. Kayaardi s. and Gök V. 2003. Effect of replacing beef fat with olive oil on quality characteristics of turkish soudjouk (sucuk). Meat sci. 66: 249-257. Kong b., Zhang H. and Xiong Y.L. 2010. Antioxidant activity of spice extracts in a liposome system and in cooked pork pat- ties and the possible mode action. Meat sci. 85: 772-778. Kowalski r., Pyrcz J. 2009. Innowacyjne dodatki technolog- iczne w przemyśle mięsnym. Przem. spoż. 63(3): 28-32. Kunachowicz H., nadolna I., Przygoda b. and Iwanow K. 2005. Ital. J. Food Sci., vol. 27 - 2015 309 tabele składu i wartości odżywczej żywności. PZWL, War- szawa, 91-148, 167-185. Lee s., Faustman c., djordjevic d., Faraji H. and decker E.A. 2006. Effect of antioxidants on stabilization of meat prod- ucts fortified with n-3 fatty acids. Meat sci. 72: 18-24. López-López I., cofrades s. and Jiménez-colmenero F. 2009. Low-fat frankfurters enriched with n-3 PuFA and edible seaweed: Effect of olive oil and chilled storage on physic- ochemical, sensory and microbial characteristics. Meat sci. 83: 148-154. Mińkowski K., Jerzewska M., Grześkiewicz s. and ro- pelewska M. 2010. oleje roślinne – cenne źródło kwasów tłuszczowych o budowie trienowej oraz innych bioakty- wnych składników. tłuszcze Jadalne 45(1-2): 31-39. Morrison W.r. and smith M.L. 1964. Preparation of fatty acid methyl esthers and dimethylaccetates from lipid with bo- ron trifluoride methanol. J. Lipid res. 5: 600-608 Muguerza E., Ansorena d. and Astiasarán I. 2003. Improve- ment of nutritional properties of chorizo de Pamplona by replacement of pork backfat with soy oil. Meat sci. 65: 1361-1367. nissen L.r., byrne d.V., bertelsen G. and skibsted L.H. 2004. the antioxidative activity of plant extracts in cooked pork patties as evaluated by descriptive sensory profiling and chemical analysis. Meat sci. 68: 485-495. nitsch P. 2007. Auf die Mischung kommt es an: omega-3-Fett- sauren als funktioneller Zusatz in Fleischerzeugnissen. Fleischwirtschaft. 87(2): 46-51. Özvural E.b. and Vural H. 2008. utilization of interesteri- fied oil blends in the production of frankfurters. Meat sci. 78: 211-216. Pcs. Polish committee for standardization. 1998. Polish standard Pn-Iso 41219:1998. sensory analysis: Meth- odology: Valuation of foodstuffs using scaling methods. Warsaw, Pcs. Pcs. Polish committee for standardization. 2000. Polish standard Pn-En Iso 6887-1:2000. Microbiology of food and animal feeding stuffs: Preparation of test samples, initial suspension and decimal dilutions for microbio- logical examination - Part 1: General rules for the prep- aration of the initial suspension and decimal dilutions. Warsaw, Pcs. Pcs. Polish committee for standardization. 2003. Polish standard Pn-En Iso 6579:2003. Microbiology of food and animal feeding stuffs: Horizontal method for detection of salmonella ssp. Warsaw, Pcs. Pcs. Polish committee for standardization. 2005a. Pol- ish standard Pn-En Iso 4833:2004+Ap1:2005. Pol- ish standard. Microbiology of food and animal feeding stuffs: Horizontal method for enumeration of microor- ganisms: Plate method at the temperature of 30 degrees c. Warsaw, Pcs. Pcs. Polish committee for standardization. 2005b. Polish standard Pn-En Iso 6887-2:2005. Microbiology of food and animal feeding stuffs: Preparation of test samples, in- itial suspension and decimal dilutions for microbiological examination - Part 2: specific rules for the preparation of meat and meat product. Warsaw, Pcs. Pcs. Polish committee for standardization. 2007. Polish standard Pn-Iso 8432:2007. Microbiology of food and an- imal feeding stuffs: Horizontal method for enumeration of coliform bacteria: Plate method. Warsaw, Pcs. Pcs. Polish committee for standardization. 2008. Polish standard Pn-En Iso 7218:2008. Microbiology of food and animal feeding stuffs: General requirements and rules for the microbiological examinations. Warsaw, Pcs. Pcs. Polish committee for standardization. 2009. Polish standard PKn-cEn Iso/ts 11133-1:2009. Microbiolo- gy of food and animal feeding stuffs: Guidelines on prep- aration and production of culture media - Part 1: Gener- al guidelines on quality control of culture media prepared in labaratorium. Warsaw, Pcs. Pelser W.M., Linssen J.P.H., Legger A. and Houben J.H. 2007. Lipid oxidation in n-3 fatty acid enriched dutch style fer- mented sausages. Meat sci. 75: 1-11. Pietrzak d., Myron M. 2008. Wpływ dodatku ekstraktu z rozmarynu na jakość hamburgerów drobiowych. rocz. Inst. Przem. Mięsn. tł. 46(3): 43-49. Pyrcz J., Kowalski r. and danyluk b. 2007. Jakość kutrow- anych kiełbas parzonych produkowanych z udziałem tłuszczów roślinnych. Med. Wet. 63(1): 118-122. radzymińska M., borejszo Z., smoczyński s.s. and Kurzyńska M. 2005. skład kwasów tłuszczowych w całodziennych posiłkach dzieci, uczniów i studentów. Zywn-nauk. tech- nol. Ja. 12(2): 118-125. shahidi F. 1990. the 2-thiobarbituricacid (tbA) methodolo- gy for the evaluation of warmed-over flavour and oxidative rancidity in meat products. In Proceedings of 36th Int. con- gress of Meat sci. & techn. Havana, cuba, pp. 1008-1014. stangierski J., Kijowski J. 2002. Żywność wygodna z mięsa drobiowego. Mięso i Wędliny. 7: 12-20. Valencia I., Ansorena d. and Astiasarán I. 2006. nutrition- al and sensory properties of dry fermented sausages en- riched with n-3 PuFAs. Meat sci. 72: 727-733. Vural H., Javidipour I. and ozbas o.o. 2004. Effects of inter- esterified vegetable oils and sugarbeet fiber on the quali- ty of frankfurters. Meat sci. 67: 65-72. Waszkowiak K. and Górecka d., Janitz W. 2001. Wpływ pre- paratu błonnika pszennego na jakość sensoryczną potraw mięsnych. Zywn-nauk. technol. Ja. 8(3): 53-61. Paper Received July 10, 2014 Accepted September 18, 2014