Chicken Breast Meat Marinated with Increasing Levels of Sodium Bicarbonate

http:// www.jstage.jst.go.jp/ browse/ jpsa doi:10.2141/ jpsa.0130079 Copyright C 2014, Japan Poultry cience Association. Chicken Breast Meat Marinated with Increasing Levels of odium Bicarbonate Massimiliano Petracci, Luca Laghi, imone Rimini, Pietro Rocculi, Francesco Capozzi and Claudio Cavani Department of Agricultural and Food ciences, Alma Mater tudiorum - University of Bologna, 47521 Cesena (FC), Italy The aim of this study was to test the effect of different sodium bicarbonate concentratio on marination performances and meat quality properties. A total of 203 samples were obtained from an homogenous batch of 24 h post mortem chicken breast meat and were subjected to vacuum tumbling in a sodium chloride solution (1.0% wt/w in final product), containing 7 different sodium bicarbonate concentratio from 0 to %. Meat ph after marination linearly responded with about 0.17 ph unit increase per 0.1% unit addition of bicarbonate. The largest marinade uptake (11.4%) was observed in samples tumbled with 0.30% bicarbonate solution, while the uptake was levelled off, thereafter higher concentratio (0.40 and 0%). Cook loss showed a decreasing trend with the increase of bicarbonate level by estimating a 1.8% decrease for 0.10% of bicarbonate addition. Overall appearance of meat was not changed, while the use of sodium bicarbonate was able to improve meat texture by decreasing hardness and chewiness. By using low-resolution Nuclear Magnetic Resonance (LR-NMR) analysis, it was observed that water seemed to exert a plasticizing effect on some biopolymers, so that the total LR-NMR signal fluctuatio were not always proportional to the water adsorption. Finally, water gain following marination does not correspond to an increase in the freezable water amount, as detected by differential scanning calorimetry. In conclusion, this study showed that sodium bicarbonate is a superior marinating agent and greater marination performances are obtained when using a concentration no higher than 0.3%. Key words: marination, NMR, poultry meat, sodium bicarbonate, water status J. Poult. ci., 51: 206-212, 2014 Received: May 3, 2013, Accepted: July 16, 2013 Released Online Advance Publication: August 25, 2013 Correspondence: Dr. M. Petracci, Department of Agricultural and Food ciences, Alma Mater tudiorum - University of Bologna, 47521 Cesena (FC), Italy. (E-mail: m.petracci@unibo.it) Introduction In the past decades, worldwide poultry meat production and coumption have increased rapidly and, in many parts of the world, per capita coumption of poultry meat is expected to grow continuously. One of the main reaso for the success of poultry meat is the increased availability of further processed products (Fletcher, 2002). The shift towards further processed products has underscored the necessity for higher standards in poultry meat quality, in order to improve seory characteristics and functional properties (Fletcher, 2002; Barbut et al., 2008). However processors have to deal with a certain variability of raw meat quality which is caused by ante-mortem, post-mortem and processing factors (Petracci et al., 2010; Petracci and Cavani, 2012). This variability can be managed during further processing by the use of functional ingredients. Functional ingredients include a variety of additives or ingredients from vegetable and animal sources which are used to achieve different functionalities on the final product (Petracci et al., 2013a). Main functionalities to be achieved by mea of functional ingredients are represented by water and fat holding capacity, binding properties (i.e. increased adhesion among meat parts or in minced meat systems), texture modulation (i.e. increase of tenderness). In addition, functional ingredients offer possibilities to lower formulation cost by mea of adding water to the meat, increase processing yield or allowing the use of cheaper raw meat sources in product formulatio (Barbut, 2002; Weiss et al., 2010; Petracci et al., 2013a). Coidering the overall functional properties of a poultry meat product, most important ones can be coidered the ability to retain water (both native or added during processing), and the ability to achieve the desired final texture. Increasing meat water holding capacity (WHC) is always a goal to reach, whereas texture can be managed in both direction of increasing tenderness (i.e. marinated breast meat) or improving bite (i.e. in nuggets produced with mechanically deboned meat) or knack (i.e. in emulsified sausages)

Petracci et al.: Broiler Meat Marinated with Bicarbonate 207 (Xiong, 2004; Petracci et al., 2013a). It is well known that myofibrillar protei are mainly respoible for the WHC and textural properties of processed meat products. Within myofibrillar protei, myosin and actin contribute most to the development of desirable gel characteristics in processed meat products. The heat-induced gelation of myosin results in the formation of a threedimeional network structure which holds water in a less mobile state. During network formation, fat and water retention are enhanced and this influences yield, texture, and cohesion of the final product (Xiong 2004; un and Holley, 2011; Petracci et al., 2013a). Among functional ingredients, sodium chloride and phosphates are the most used because of their ability to enhance functionality of myofibrillar protei (Barbut, 2002; Petracci et al., 2013b). In the recent years, the use of alkaline salts such as bicarbonates has gained a certain interest (Petracci et al., 2013a). The first studies were focused on using bicarbonate to minimize the problem of pale, soft and exudative (PE) in pork (Kauffman et al., 1998; Van Laack et al., 1998; Wynveen et al., 2001) and poultry (Woelfel and ams, 2001; Alvarado and ams, 2003). More recent studies found that sodium bicarbonate was able to reduce shear force and improve yield of enhanced poultry meat (en et al., 2005; Petracci et al., 2012). When added in marinades, bicarbonate had a very high alkaline power on meat and showed a greater ability to increase meat ph than sodium tripolyphosphate (0.7 vs. 0.3 ph units) (Petracci et al., 2012). The latter observed that marinades containing sodium bicarbonate in association with salt allowed to greatly improve product yield. This effect is most likely related to its alkalinisation effect which moved meat ph away from the isoelectric point of myofibrillar protei and increased net negative charge. Previous research conducted with low-resolution nuclear magnetic resonance (LR-NMR) indicated that the combination of bicarbonate and sodium chloride remarkably increased the portion of entrapped water in myofibrillar spaces (Petracci et al., 2012). This study was aimed at evaluating marination performances and effect on meat quality traits when different levels of sodium bicarbonate with a fixed concentration of sodium chloride were used. Materials and Methods Experimental Procedures A batch of broiler breast fillets was obtained from a local abattoir at 24 h post mortem from a flock of birds (Cobb 500, females, 46 day-old, 2.48 kg) reared and slaughtered under commercial conditio. From each Pectoralis major muscle, four samples of cylindrical shape with the dimeio of 1 cm height and 4 cm diameter were cut in order to yield seven homogeneous groups (29 samples/group) for ph and colour (L, a, b). amples were subjected to vacuum tumbling in marinated solutio (12% water: meat ration, wt/wt) having the same sodium chloride concentration (7.7% wt/wt) with 7 sodium bicarbonate levels: 1) 0.0 (), 2) 0.4 (), 3) 0.8 (); 4) 1.6 (); 5) 2.4 (); 6) 3.2 (); 7) 3.8% (). The final salt concentration was about 1% (g/100 g meat) with 0 to % (g/100 g meat) sodium bicarbonate. Before and after being tumbled, 20 samples/group were weighed to determine marinade uptake and placed in covered plastic boxes on raised wire racks in a 2-4 cooler. After 24 h, samples were again weighed to determine drip loss, and colour (Lab) was also measured. From each group, 10 samples were used to determine ph, expressible moisture, water activity (AW), freezable water (FW) and LR-NMR relaxation properties on uncooked meat, while the remaining 10 samples were individually vacuum-packed under 950 mbar and cooked in a 80 water bath for 12 min, until core temperature reached 80, and used to assess cooking loss, ph, colour (Lab), total moisture, Aw, FW and LR-NMR relaxation properties. In addition, 9 samples after cooking per each group including a further group coisting of unmarinated cooked samples were exclusively used to analyze texture profile analysis. Analytical Methods Colour. The CIE (1978) system colour profile of lightness (L), redness (a), and yellowness (b) was measured by a reflectance colorimeter using illuminant source C. The colorimeter (Minolta Chroma Meter CR-400, Minolta Italia.p.A., Milano, Italy) was calibrated throughout the study using a standard white ceramic tile. Colour was measured in single on the centre of samples before tumbling, after tumbling and after cooking. ph. The ph was determined using a modification of the iodoacetate method initially described by Jeacocke (1977). Approximately 2.5 g of meat samples before tumbling, after tumbling and after cooking were minced by hand, homogenized in 25 ml of a 5 mm iodoacetate solution with 150 mm potassium chloride for 30 s, and the ph of the homogenate was determined using a ph meter (Bibby cientific Ltd, T/As Jenway, Essex, UK) calibrated at ph 4.0 and 7.0. Weight changes during marination and cooking. Weight of individual samples were recorded before tumbling (wt 1 ), after tumbling (wt 2 ), after 24 h storage (wt 3 ) and after cooking (wt 4 ) following recommendatio given by Petracci and Baeza (2011). The following calculatio were made: Marinade uptake (%)=[(wt 2 ) (wt 1 )/(wt 1 )] 100 Drip loss (%)=[(wt 2 ) (wt 3 )/(wt 2 )] 100 Cooking loss (%)=[(wt 3 ) (wt 4 )/(wt 3 )] 100 Yield (%)=(wt 4 /wt 1 ) 100 Expressible moisture. Expressible moisture was measured with TA. HDi Heavy Duty texture analyzer (table Micro ystems Ltd., Godalming, urrey, UK) as described by Parks et al. (2000). amples were cut into 1 cm cubes, and two sheets of 12.5-cm Whatman #1 filter papers were positioned on the top and bottom of the sample to absorb expressed moisture. A 12.5-cm diameter flat disc attachment was lowered onto the sample at a rate of 100 mm/min. A maximum load of 400 N was applied to the sample for 15 s. amples typically reached a deformation of 88%. The sample weight before and after compression was recorded and expressible moisture was expressed as a percentage of the net weight difference from the initial weight.

208 Journal of Poultry cience, 51 (2) Water activity (A w ). The A w was measured at cotant temperature (25±1 ) by a water activity meter mod. Aqualab (Decagon Devices Inc., Pullman, UA) which bases its measure on the chilled-mirror dewpoint technique. For each marination treatment, A w was detected on three samples before tumbling, after tumbling and after cooking. Freezable water (FW). The amount of FW was evaluated by a Pyris 6 DC (Perkin Elmer Corporation, Wellesley, UA) on 3 samples/group before tumbling, after tumbling and after cooking. The DC was equipped with a low-temperature cooling unit Intercooler II (Perkin Elmer Corporation, Wellesley, UA). Temperature calibration was performed with ion exchanged distilled water (m.p. 0.0 ), indium (m.p. 156.60 ) and zinc (m.p. 419.47 ). Heat flow was calibrated using the heat of fusion of indium (Δh=28.71 J/g). For the calibration, the same heating rate used for sample measurements was applied and a dry nitrogen gas flux of 20 ml/min was used. Each sample (about 20 mg) were weighed in 50 μl aluminium pa with a small spatula, hermetically sealed, and then loaded onto the DC itrument at room temperature, using an empty pan of the same type as a reference. amples were then cooled at 5 /min to 60, held for 1 h and then scanned at 5 /min to 20 (Brake and Fennema, 1999). FW was determined as: FW= ΔHm ΔH w where ΔH w (325 J g -1 ) is the latent heat of melting for gram of pure water at 0 (Roos, 1986) and ΔH m (J g -1 )is the measured latent heat of melting of water for gram of sample, obtained by the integration of the melting endothermic peak. FW amount was expressed as g gfw -1. NMR Relaxation Measurements. The proton traverse relaxation (T2) decays in breast meat after marination and after cooking was recorded at the operating frequency of 20 MHz with a Bruker (Milan, Italy) Minispec PC/20 spectrometer using standard Carr-Purcell-Meiboon-Gill (CPMG) pulse sequence (Meiboom and Gill, 1958). A sample of about 600 mg of meat was placed iide a 10 mm (outer diameter) NMR tube, thus forming a small cylinder which height did not exceed the active region of the radio frequency coil. Each measurement comprised 30, 000 points with a TAO-spacing (time between subsequent 180 pulses) of 80 μs and a relaxation delay of 3.5 s. All the measurements were performed at a cotant temperature of 24. The CPMG decays were normalized to the corresponding sample weight and traformed into relaxograms (i.e. continuous distributio of relaxation times) through the program UPEN (Borgia et al., 1998). Each relaxogram was interpreted in agreement with previous studies on pork (Bertram et al., 2002) and turkey (Bianchi et al., 2004). Total moisture. The moisture content of the cooked meat samples was determined by AOAC procedures (1990). Texture profile analysis. Textural parameters were determined on core samples after cooking (3 cm diameter, 0.8 cm height), axially compressed (50 kg load cell; crosshead test speed 1 mm/s) to 50% of their initial height in a double compression cycle: hardness (kg, maximum force required to compress the sample), cohesiveness (A2/A1, extent to which the sample could be deformed prior to rupture, where A1 represents the total energy required for the first compression and A2 the total energy required for the second compression), springiness (D2/D1, the ability of sample to recover its original form after the deforming force is removed where D1 represents the initial compression distance and D2 the distance detected for the second compression), gumminess (hardness cohesiveness, the force needed to disintegrate a isolid sample to a steady state of swallowing), chewiness (springiness gumminess, the work needed to chew a solid sample to a steady state of swallowing) (Lyon et al., 2010). tatistical Analysis Data were analyzed through a One-way ANOVA testing the type of marination treatment as main effect. When the effect was significant, the mea were separated using Duncan multiple range test. The calculatio were performed on A software (A Ititute, 1988). Results and Discussion The ph of marination solution increased from 7.05 to 8.31 as the bicarbonate was added in a step-wise pattern resulting a 0.17 ph unit increase per 0.1% unit addition of bicarbonate (Table 1). A similar ph trend was seen in cooked meats with a slightly lower variation (0.67 units) between the zero control () and the maximum bicarbonate (). These values are agreed with Petracci et al. (2012) and en et al. (2005), who evidenced the very high alkalinisation effect of bicarbonate. It is important to note that high ph values of poultry meat may support microbial growth as stated by Allen et al. (1996), so high level of sodium bicarbonate should be used carefully or avoided, because it will drastically limit product shelf-life. As for meat colour (Table 2), overall appearance of meat after marination and cooking was not affected by marination, however, a darker over the zero bicarbonate control was seen in the samples. This agrees with previous studies (Alvarado and ams, 2003; en et al., 2005; Petracci et al., 2012) and with the observatio of Trout (1989), who noticed that a high ph reduced heat denaturation of myoglobin during cooking, thus leading to increased darkness. There were significant differences among treatments (P< 0.01) for marination uptake, drip loss, expressible moisture, cooking loss, yield and total moisture exhibited significant differences among treatments (P<0.001) (Table 3). The solution with 0.05% bicarbonate did not improve marinade uptake in respect to the use of salt alone, otherwise concentration greater than 0.1% determined higher weight gai. The greatest marinade uptake (11.4%) was observed in samples tumbled with 0.30% bicarbonate solution, while higher concentration (0.40 and 0%) exhibited lower marinade uptake similar to the results from 0.10-0.20% bicarbonate solutio. Drip loss was not significantly higher than the control, except the and samples suggesting that these samples are less able to retain the added water. amples treated with bicarbonate concentration above

Petracci et al.: Broiler Meat Marinated with Bicarbonate 209 Table 1. ph of marinade solutio and broiler breast meat before and after marination, and cooking (n= 10/group) Marinade solution ph ph before marination ph after marination ph after cooking 7.05 5.75 5.81 g 5.99 f 7.84 5.76 5.89 f 6.08 e 7.86 7.88 7.89 8.27 8.31 5.76 5.77 5.77 5.76 5.77 0.01 5.98 e 6.23 d 6.38 c 6.50 b 6.67 a 0.04 6.19 d 6.31 c 6.47 b 6.59 a 6.65 a 0.03 =alt (1% wt/wt); =alt (1% wt/wt) and Bicarbonate with increasing concentration from 0.05 to % (wt/wt); =P 0.001; =not significant; a-g Mea within a row followed by different superscript letters differ significantly (P 0.05). Prob. Table 2. Colour (Lab) of broiler breast meat before and after marination, and after cooking (n= 20/group) Before marination lightness (L) redness (a) yellowness (b) After marination lightness (L) redness (a) yellowness (b) After coking lightness (L) 1 redness (a) 1 yellowness (b) 1 54.7 1.30 2.11 51.1 1.02 2.72 84.6 ab 1.66 8.94 54.7 0.87 2.13 51.0 0.82 2.90 85.2 a 1.56 8.58 54.3 1.15 2.22 50.6 1.09 2.89 84.4 ab 1.80 8.94 54.5 0.95 2.53 51.7 1.11 2.97 84.7 a 1.62 8.29 55.1 0.95 2.06 52.3 0.71 3.39 83.1 bc 1.35 8.88 55.2 1.05 2.12 84.2 abc 1.51 8.45 54.5 3 1.82 82.7 c 1.05 8.49 0.28 0.08 =alt (1% wt/wt); =alt (1% wt/wt) and Bicarbonate with increasing concentration from 0.05 to % (wt/wt). 1 n=10/group. =P 0.01; =not significant. a-c Mea within a row followed by different superscript letters differ significantly (P 0.05). 50.8 1.12 2.59 51.1 0.63 3.05 0.25 0.06 0.11 0.20 0.08 Table 3. Marinade uptake, drip loss, expressible moisture, cooking loss, yield and total moisture after cooking of marinated broiler breast meat Marinade uptake (%) 1 7.9 c 7.7 c 8.9 b 9.4 b 11.4 a 9.6 b 9.1 b 0.17 Drip loss (%) 1 1.96 cde 1.73 de 2.01 cd 1.66 e 2.56 a 2.18 bc 2.47 ab 0.05 Expressible moisture (%) 2 14.1 a 14.1 a 13.1 a 11.9 ab 10.2 b 10.6 b 10.0 b 0.36 Cooking loss (%) 2 18.2 a 17.6 a 14.3 b 13.8 b 12.7 b 10.2 c 9.0 c 0.43 Yield (%) 2 86.7 d 87.1 d 91.7 c 93.3 bc 95.6 ab 96.7 a 97.1 a 6 Total moisture (%) 2 71.1 b 71.1 b 71.7 b 72.5 a 72.8 a 72.7 a 73.2 a 0.14 =alt (1% wt/wt); =alt (1% wt/wt) and Bicarbonate with increasing concentration from 0.05 to % (wt/wt). 1 n=20/group; 2 n=10/group. =P 0.001. a-e Mea within a row followed by different superscript letters differ significantly (P 0.05). 0.30% had lower expressible moisture, while cooking loss showed a decreasing trend with the increase of bicarbonate level. Yields showed the highest values for treatment with concentration above 0.30% of bicarbonate and total moisture increased in respect to groups when the bicarbonate level was above 0.20%. The higher marinade uptake and retention ability in bicarbonate samples is expected from its alkaline effect, increasing muscle ph and net negative charges. This leads to muscle fibre expaion (swelling) caused by electrostatic repulsion which allows more water to be immobilised in the myofibrillar lattice (Offer and Knight, 1988). It was also suggested that the use of bicarbonate induced a higher protein solubilization after marination, which decreases the negative effects of protein denaturation during cooking (Bertram et al., 2008).

210 Journal of Poultry cience, 51 (2) Table 4. Nuclear magnetic properties of broiler breast meat after marination and after cooking (n=10/group) After marination Extra-myofibrillar Myofibrillar Bound After cooking Extra-myofibrillar Myofibrillar Bound Inteity Inteity Inteity Inteity Inteity Inteity 3.6 112.1 ab 92.9 49.2 ab 3.5 0.6 2.8 a 101.9 ab 93.3 31.7 5.2 3.8 3.7 3.9 3.8 3.6 4.0 0.09 136.2 a 114.0 ab 98.8 b 123.9 ab 91.0 b 92.8 b 4.84 93.4 93.2 93.5 93.5 93.4 93.1 0.18 50.8 a 49.6 ab 46.6 abc 47.6 abc 45.2 ac 42.4 c 2.23 3.2 3.9 3.1 3.0 4.4 3.5 0.16 0.6 0.6 0.6 0.6 0.6 0.6 0.01 2.3 ab 8 b 94.1 29.8 5.0 0.4 2.5 a 132.2 ab 94.5 31.1 4.2 0.4 2.8 a 135.6 a 94.7 32.6 5.9 =alt (1% wt/wt); =alt (1% wt/wt) and Bicarbonate with increasing concentration from 0.05 to % (wt/wt). =P 0.01; =not significant. a-c Mea within a row followed by different superscript letters differ significantly (P 0.05). 2.6 a 124.5 ab 94.7 33.0 4.3 0.4 1.8 b 108.6 ab 94.5 31.3 4.6 2.3 ab 87.0 ab 93.9 32.5 5.2 6.47 0.22 0.32 0.21 0.01 Proton traverse relaxation (T2) weighted signals acquired by mea of LR-NMR at 20 MHz is known to allow the observation of three proton populatio, with T2 below 1 ms, around 50 ms and around 100 ms respectively. The first population, representing roughly the 3% of the total signal, can be attributed to water tightly associated to macromolecules (Bertram et al., 2008), mainly protei, of the meat and it commonly loosely defined as bound water (Petracci et al., 2012). The second and third signals are commonly accepted to be due to water and biopolymers located iide and outside the myofibrils respectively, the latter thus informative about the water lost by the meat during coervation or upon cooking. The three proton populatio were observed individually by applying a two steps approach set up for other spatially inhomogeneous food matrices (Davenel et al., 2002; Panarese et al., 2012), made by the inversion of the LR- NMR signals towards a continuous distribution and then a discrete number of exponential curves. Table 4 summarizes for each proton pool the inteity and average T2 for each treatment coidered. The signal from the spaces outside the fibrils was not significantly modified with the increase of bicarbonate concentration, on the other hand the signal from the myofibrils reaches a maximum for treatment, and then decreases again. In parallel in both compartments a greater number of proto gets visible because the ph moves away from the protei isoelectric point, so that the T2 of both decreases. This effect has been exteively described by Panarese et al. (2012) and Petracci et al. (2012). The comparison between cooked and marinated samples reveals the plasticizing effect of cooking on protei, with the coequent visibility of new proto. In fact, even if cooking decreases the amount of water iide meat, the total signal from cooked samples is 1-1.5% higher than the corresponding marinated sample. uch coideration is reinforced by the separate observation of intra and extra-myofibrillar spaces. The signal from the former decreases upon cooking in agreement with the observatio of Bertram et al. (2008). At the opposite the correlation between intramyofibrillar proto pool signal and bicarbonate treatments shows a parabolic trend, with a maximum for treatments -. Meat A w and FW before and after tumbling as well as after cooking are shown in Table 5. The A w of non-marinated meat samples was 0.991, in agreement with previous data (Petracci et al., 2012), whereas the FW was 0.637 g/g of fresh sample weight, which mea that in raw meat, about the 90% of the total water had enough mobility to freeze. Raw samples marinated only with salt () did not show significant differences from the non-marinated group not for A w nor for FW, as happened for samples marinated with salt and low sodium bicarbonate levels (, and ). With higher sodium bicarbonate amount in the marinade, a significant decrease of A w was detected that was of the same extent for, and. Even if it is very limited, this decrease could positively influence the product stability and its shelf-life. It is important to underline that these samples showed also significantly lower values of expressible moisture (Table 3). According to Barbut (2002), expressible moisture is mainly represented by the water in the extracellular spaces, which is likely the water fraction more correlated with A w. Generally the total moisture increase of enhanced samples does not correspond to an increase in A w, even promoting its decrease at the highest sodium bicarbonate levels. The concomitant increases of solute concentration with humectant action, protein solubilisation (that increase their capacity to bind water) as well as electrostatic interactio between actin and myosin and marinated io can be the main causes for the detected A w reduction (Petracci et al., 2012). In terms of FW, only sample resulted significantly lower compared with the control, while for the other samples FW reduction has not been detected. According to

Petracci et al.: Broiler Meat Marinated with Bicarbonate 211 Table 5. Water activity (A w ) and freezable water content (FW) of broiler breast meat before and after marination, and after cooking (n=3/group) NM Before marination A w 0. 991 0. 991 0. 991 0. 991 0. 991 0. 991 FW(ggfw -1 ) 0. 637 0. 637 0. 637 0. 637 0. 637 0. 637 After marination A w 0. 991 a 0. 988 a 0. 991 a 0. 988 ab 0. 991 a 0. 986 b FW(ggfw -1 ) 0. 637 a 0. 616 a 0. 617 ab 0. 626 a 0. 636 a 0. 616 ab After cooking A w 0. 989 a 0. 986 a 0. 989 a 0. 989 a 0. 989 a 0. 989 a FW(ggfw -1 ) 0. 538 0. 546 0. 566 0. 563 0. 577 0. 579 NM=non-marinated meat; =alt (1% wt/wt); =alt (1% wt/wt) and Bicarbonate with increasing concentration from 0.05 to % (wt/wt). =P 0.01; =P 0.05; =not significant. a-b Mea within a row followed by different superscript letters differ significantly (P 0.05). 0. 991 0. 637 0. 987 b 0. 606 ab 0. 988 a 0. 572 0. 991 0. 637 0. 985 b 0. 583 b 0. 985 b 0. 556 0. 001 0. 009 0. 001 0. 011 0. 001 0. 015 Table 6. Textural parameters of cooked broiler breast meat (n=9/group) Hardness (kg/g) Cohesiveness Gumminess (kg/g) pringiness Chewiness (kg/g) NM 3.77 a 3.41 a 2.87 bc 2.76 bc 2.79 b 2.76 b 2.73 b 2.49 b 0.08 2.27 d 2.48 c 2.50 bc 2.69 ab 2.71 ab 2.61 abc 2.65 abc 2.62 abc 0.03 8.54 a 8.39 a 7.15 ab 7.46 ab 7.56 ab 7.18 ab 7.22 ab 6.50 b 0.17 1.70 a 1.49 b 1.45 bc 1.39 bc 1.38 c 1.41 bc 1.41 bc 1.40 bc 0.02 14.4 a 12.5 a 10.4 b 10.3 b 10.4 b 10.1 b 10.2 b 9.1 b 0.29 NM=non-marinated meat; =alt (1% wt/wt); =alt (1% wt/wt) and Bicarbonate with increasing concentration from 0.05 to % (wt/wt). =P 0.001; =P 0.05. a-d Mea within a row followed by different superscript letters differ significantly (P 0.05). Pearce et al. (2011), water in meat is structurally arranged in layers around polar molecules and between layers of cellular materials. About 5% of the water contained in muscle tissue exists as true hydration water, bound to protei by macromolecular of multimolecular adsorption. This water is not free; it has an ice-like structure (liquid crystal), is unfreezable, is unaffected by charges on the muscle protein (ph), and is unavailable to participate in reactio. In this study, FW outcomes evidenced that in the control samples, the unfreezable water content was about 10% of the total amount and its changes caused by marination were very limited. After cooking, the A w values of the different samples did not show significant differences, with the exception of sample the showed the significantly lower value (0.985). Even in this experiment, cooking promoted a reduction of FW, but all the samples did not show significant differences. Finally texture profile analysis of cooked meat samples was shown in Table 6. All the traits were affected by treatment. For hardness and chewiness it was found that samples marinated with a solution containing only sodium chloride showed values similar to un-marinade samples, while the use of sodium bicarbonate allowed to obtaining meat with lower hardness and chewiness. Overall samples marinated with bicarbonate showed higher cohesiveness, less gumminess and less springiness compared to control and un-marinated samples. These results agree with heard and Tali (2004) who found that sodium bicarbonate was able to reduce shear force. heard and Tali (2004) hypothesized that tenderizing effect in pork was also due to the release of carbon dioxide during cooking, resulting in a change in the structure of meat. In conclusion, this study showed that sodium bicarbonate in combination with sodium chloride is a superior marinating agent and greater marination performances are obtained when using a concentration of at least 0.3%. This can be implemented to develop processed poultry products with no added phosphates, in order to match the request to avoid the nutritional drawbacks which have been recently evidenced in relation with the use of phosphates. Compared with differential scanning calorimetry, technique, sample analyses via LR-NMR yielded an additional degree of details, permitting not only the study of bulk water modificatio, but also the plasticizing effect on matrix proto located in meat structure, caused by marination treatment. Further studies are in progress in our laboratory to investigate the evolution of physico-chemical and biological reactio, bound to product stability and shelf-life of sodium bicarbonate marinated products. Acknowledgments This research was funded by Bank Foundation of Cassa di Risparmio di Cesena by way of Polo cientifico - Didattico di Cesena University of Bologna, Italy.

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