EFFECT OF ESSENTIAL OILS ON CHEMICAL AND BACTERIOLOGICAL QUALITY OF CHICKEN BURGER.

تأثیر بعض الزیوت الأساسیة على جودة برجر الدجاج المحفوظة بالتبرید

محمد عبدالله حسین ، عبدالسلام الدیدامونى حافظ وریهام عبدالحمید جمعة

قسم مراقبة الأغذیة –کلیة الطب لبیطرى –جامعة الزقازیق

فى هذه الدراسة تم عمل أربع مجموعات من برجر الدجاج الأولى کمجموعة ضابطة ، والثانیة والثالثة والرابعة تحتوی على الزیوت الأساسیة للکمون ،الزعتر والثوم بترکیز 1٪ على التوالی. تمت دراسة تأثیر المعالجات المختلفة على الأس الهیدروجینی والمواد النیتروجنیة المتطایرة  وحمض الثیوباربیتریک والعدد الکلى للبکتریا الهوائیة  وعدد المکورات العنقودیة وعدد المکورات المعویة خلال أیام التبرید عند 3 ± 1 درجة مئویة. کانت متوسطات الأس الهیدروجینی والمواد النیتروجنیة المتطایرة  وحمض الثیوباربیتریک (7.21 ± 0.09 و 30.89 ± 3.64 مجم / 100 جم و 1.29 ± 0.04 مجم MDA / کجم) و (6.36 ± 0.06 و 16.76 ± 1.26 مجم / 100 جم و 0.98 ± 0.02 مجم MDA / کجم) ، (6.20 ± 0.07 ، 13.97 ± 1.34 مجم / 100 جم ، 0.76 ± 0.02 مجم MDA / کجم) و (6.13 ± 0.08 ، 12.81 ± 1.74 مجم / 100 جم ، 0.64 ± 0.02 مجم MDA / کجم) فی المجموعة الضابطة ، ، المجموعات المعالجة بالکمون والزعتر والثوم ، على التوالی فی الیوم التاسع من التبرید. ووجد أن متوسط القیم  للعدد الکلى للبکتریا الهوائیة  وعدد المکورات العنقودیة وعدد المکورات المعویة کانت (7.63 ± 0.46 و 5.03 ± 0.35 و 5.17 ± 0.31 لوغاریتم 10 مستعمرة بکتیریة /جم) و (6.92 ± 0.44 و 4.21 ± 0.31 و 4.34 ± 0.29 لوغاریتم 10 مستعمرة بکتیریة /جم) و (6.64 ± 0.43 و 4.14 ± 0.29 و 4.08 ± 0.24 لوغاریتم 10 مستعمرة بکتیریة /جم) و (6.31 ± 0.46 و 3.91 ± 0.27 و 3.97 ± 0.25 لوغاریتم 10 مستعمرة بکتیریة /جم) فی المجموعة الضابطة والکمون والزعتر والثوم ، على التوالی فی الیوم الثالث عشر من التبرید. أظهر زیت الثوم ترکیز 1٪ تأثیرات جیدة  فی تثبیط التغیرات الکیمیائیة وتقلیل نمو البکتیریا.

OF ESSENTIAL OILS ON CHEMICAL

AND BACTERIOLOGICAL QUALITY

OF CHICKEN BURGER.

Mohamed A. Hussein ;Abd El Salam E. Hafez

and Reham A.Gomaa

Food Control Department, Faculty of Veterinary Medicine,

Zagazig University, Zagazig 44519, Egypt

Key Words: Chicken burger, Staphylococcus, Enterococcus, thiobarbituric acid, total volatile basic nitrogen, garlic oil, thyme oil, cumin oil.

ABSTRACT

Four batches of chicken burger first as control, second,third and fourth groups contained cumin, thyme, garlic essential oilsat concentration 1%, respectively. The effect of different treatments on pH, total volatile basic nitrogen (TVB-N), Thiobarbituric acid (TBA), and aerobic plate count (APC), Staphylococcus count and Enterococcus count was studied during chilling days at 3±1^°C. The mean values of pH, TVB-N and TBA was (7.21±0.09, 30.89±3.64 mg/100g and 1.29±0.04 mg MDA/kg), (6.36±0.06, 16.76±1.26 mg/100g, 0.98±0.02 mg MDA/kg), (6.20±0.07, 13.97±1.34 mg/100g, 0.76±0.02 mg MDA/kg) and (6.13±0.08, 12.81±1.74 mg/100g, 0.64±0.02 mg MDA/kg) in control, cumin, thyme and garlic treated groups, respectively on 9^th day of chilling. The mean values of APC, Staphylococcus and Enterococcus were (7.63±0.46, 5.03±0.35and 5.17±0.31 log₁₀CFU/g), (6.92±0.44, 4.21±0.31and 4.34±0.29 log₁₀CFU/g), (6.64±0.43, 4.14±0.29 and 4.08±0.24 log₁₀CFU/g) and (6.31±0.46, 3.91±0.27 and 3.97±0.25 log₁₀CFU/g) in control, cumin, thyme and garlic treated groups, respectively on 13^th day of chilling. Garlic essential oil at concentration 1% showed higher desirable effects in retarding chemical changes and decreasing bacterial growth.

INTRODUCTION

Chicken burger are comminuted processed chicken product made from chicken meat, with combination of water, binders, and seasoning. In last year's due to increased consumer needs and competition in the meat processing, ingredients have been incorporated into chicken meat products to develop a healthier product. The demand for natural replacements of chemicals with natural additives, in foodstuffs to extend  shelf life , decreasing lipid oxidation and deteriorative changes, so using of essential oils (EOs) is obtaining considerable attention (Hussein et al., 2018). Also, the antimicrobial activity exhibited by Essential oils against food poisoning bacteria has been demonstrated by several studies as, Alzoreky and Nakahara (2003), Vermaet al.( 2012) and Akinpeluet al (2015) they found that the antimicro­bial activity of the thyme essential oil is more effective on Gram-positive than Gram-negative bacteria by in­terfering with the cell wall. Plant extracts components as phenolic compounds possess antimicrobial activity by interfere with the phospholipids bilayer of cell membranes causing an increase in permeability and leakage of vital intracellular components and affect bacterial enzymes systems. Allicin and other sulfur compounds are thought to be the major compounds responsible for the antimicrobial effect of garlic. Garlic is effective against a number of Gram-negative, Gram-positive, and acid-fast bacteria, including Staphylococcus, Salmonella, Vibrio, Mycobacteria, and Proteus species (Abdullah et al.,1988). The Gram positive S. aureuswas more susceptible to the toxic effects of garlic than its gram negative counterparts (Abubakar, 2009).The study conducted to investigate the effect of some natural oils to control chemical and microbial changes in chicken burger.

Sample preparationMATERIALS AND METHODS

About 6 Kg of chicken burger (Minced broiler breast 70 %, fat 15 %, starch 3.5 %, cold water 10 % and salt 1.5 %) are directly transported to the laboratory in an ice box. The mixture divided into four groups.First control group , second group treated with addition of 15 ml of cumin oil, thired group treated with addition of 15 ml of thyme oil and fourth group treated with 15 ml garlic oil (each group one and half kilograms). For evaluation the effect of essential oils as natural preservatives in prepared chicken burger groups were kept under chilling condition at 3±1^{O Þ}Cand examined after formulation (zero time) then sampled at 2^nd day, 4^th day , 6^th day,9^th day,11^th day and 13^th day of storage at 4^OC.

Chemical examinations

Determination of pH according to Pearson, (2006) in briefly approximately 10 g of the sample were blended in 10ml of neutralized distilled water. The homogenate was left at room temperature for 10 minutes with continuous shaking. The pH value was determined by using an electrical pH meter (Bye model 6020, USA). Total volatile basic nitrogen (TVB-N) content was estimated according to EOS 63/9 (2006).Thethiobarbituric acid (TBA) content was calculated by the method of EOS63/10 (2006).

Bacteriological examinations

The preparation of the sausage samples and serial dilutions were performed according toISO 6887-2 (2003).Brieflytwenty five grams of eachsample were homogenized aseptically with mixing in 225 ml of 0.1 % Buffered Peptone Water (BPW,  HIMEDIA,  M614-500G)in a stomacher (Colworth, 400) for 2.5 min at room temperature (25^ºCand then allowed to stand for 5 min to provide a homogenate which represents the dilution of 10^-1). Quantity of 1 ml of the homogenate was transferred into a sterile test tube containing 9 ml of 0.1% BPW, then ten folds serial dilutions were prepared up to the required dilution (10^-9). Enumeration of APC was done according to ISO 4833-1: (2013) using pour plate method of 1ml onto plate count agar (Oxiod CM325) then incubated at 30^O C. Staphylococcus count count carried out Baired-Parker agar medium plates (Oxoid, CM 275) according to ISO, 6888-1: (1999).Enumeration of Enterococcus count carried out on Bile EsculinAzide ager (BEA, HIMEDIA, and M340).The BEA agar was inoculated by spreading 0.1 ml of the ready prepared serial dilutions onto the surface. The agar plates were incubated for 24 h at 37±0.5^°C aerobically (ISO 7899-2, 2000).  The medium inoculated by spreading 0.1 ml of the ready prepared serial dilutions onto the surface. The agar plates were incubated for 48 h at 37±0.5^°C aerobically.

 All values of chemical and bacteriological analysis are presented as means ± standard error (SE). All microbial counts were converted to log₁₀ CFU/g values.  Kruskal-wallis H One-way analysis of variance (ANOVA) post hoc Bonferroni correction to estimate the differences in chemical and bacterialcounts. P-values   less than 0.05 were considered statistically significant. The difference between the treatments groups in the decontamination trial were analyzed by One-way ANOVA.  p- values less 0.05 were considered statistically significant.

RESULTS AND DISCUSSION

The pH value is an important physicochemical characteristic to decide the quality and shelf life of sausage. The data in Table (1)showed that pH from the 3^rd day in in control groups significantly higher (p< 0.05) than treated groups. Thus, attributed to the activity of essential oils against bacteria acting on protein with formation of ammonia leading to increase in pH (Valencia et al., 2008).Similar results have been reported before by Naliniet al. (1998) who stated that thyme oil decreases the values of the pH; Salem et al. (2010) who stated that, minced beef treated with 1.0 and 1.5 % of thyme oil showed lower pH values in comparison with untreated samples (control) after 6 days of cold storage; and Alsaiqaliet al. (2016) who reported that the treated samples with 1.2 % of thyme, cumin reduced the value of pH to 6.58, 6.59 compare to the control samples after 4 days of storage.Protein and non-protein nitrogenous materials in burger are degraded by several enzymatic action and microbial activity, which lead to the production of volatile nitrogen. The amount of TVB-N is a very good chemical indicator to assess the quality and freshness of burger. From the results achieved in table (1), it could be noticed that no significant effects (P> 0.05) of essential (at zero time) between control and treated groups.Significant increase (p< 0.05) in TVB-N content of control on comparing with garlic 1% treated from the 3^rd day. Meanwhile, on 6^th and 9^th day significant increases in control (p< 0.05) on comparing with thyme and garlic treated groups. The finding attributed to rapid growth and multiplication of bacteria acting on protein in control groups led to degradation of protein and the formation of free amines, trimethylamine, dimethylamine and ammonia (Salehet al., 2017). Our findings are quite similar to the published results by Naliniet al. (1998), El-Desoukyet al. (2006) and Salem et al. (2010) who stated that, the use of thyme oil successfully decreased the rate of TVN in treated beef in comparison to the control samples after six days of cold storage. While, Alsaiqaliet al. (2016) reported that the means of TVN values of treated samples with 1.2 % thyme and cumin oils were significantly low in comparison to the untreated samples (control) after four days of cold storage.Thiobarbituric acid (TBA) is very important measures that indicates the degree of lipid oxidation state and later on rancidity. The results in table (1) declared that using of essential oil thyme 1% and garlic 1% in both reduced TBA values in treated groups (P< 0.05) on comparing with the control group from the 6^th and 9^th day. The effect of essential oil due to high percentage of phenolic compounds that act as natural antioxidant, which can efficiently retard oxidative reactions (Sharma et al., 2017). These results were in line with Beltran et al. (2004) who reported that 0.04% addition of rosemary extract to minced meat resulted in strong oxidation-stabilizing properties. However, Fernandez-Lopez et al. (2005), Moreno et al. (2006), Georganteliset al. (2007), Pietrzak and Myron, (2008) reported the anti-oxidative properties of Rosmarinusofficinalis. Naliniet al. (1998), Alsaiqaliet al. (2016) reported that thyme oil decreases the values of the TBA significantly in comparison to control samples. Ashour and El-Astal, (2005) and Kassemet al. (2011) who reported low values of TBA in treated meat with 0.05 % thyme oil after six days of storage at 4 °C. These results disagreed with another study conducted by Sharafati-Chaleshtoriet al. (2015) who did not observe any significant reduction in TBA values after adding different concentrations of essential oil to raw beef burger during storage 4 °C for 12 days.

^(a,b,c) different superscript letters in the same column (of each parameter) indicate significant differences (p < 0.05).

Total bacterialcount is a commonly used microbiological methodfor estimatingshelf-life of food.The data in table (2) showed significant decrease (p< 0.05) in APC in garlic 1% treated group start from zero day and extend all over the storage days. On the other hand significant decreases in thyme 1% treated group start from 6^th day and in cumin 1% start from 9^th day   of storage when compared with control group. The finding nearly similar to Uhartet al. (2005) indicated that after 3 days of storage of ground beef samples treated with garlic extract, 0.38-log₁₀CFU/g reduction was observed. Essential oils contains active principles responsible for the bactericidal effects, garlic holds up the highest concentration of sulfur compounds like allicin and others that having biological activities. These are responsible for not only its pungent smell, but also for its medicinal value, with effective anti-microbial properties (Corzo-Martinez et al. 2007).Cumin oil are very rich with natural compounds such as cuminaldehyde, limonene and linalool that have both antimicrobial and antioxidant activity (Derakhshanet al. 2008). Thyme oil contains rich in thymol, carvacol and para-cymene Stojkovićet al. (2013).

^(a,b,c)Means on the same raws carrying different superscript sm

all letters are significantly different (P< 0.05).

Presence of high number of Staphylococcus/g of burger may indicate a tendency towards presence of S.aureus and predication of health hazard.The data in table (3) showed significant decrease (p< 0.05) in Staphylococcus count in garlic 1% treated group start from zero day and extend all over the storage days. On the other hand significant decreases in thyme 1% treated group start from 6^th day and in cumin 1% start from 9^th day   of storage when compared with control group. The results were in accordance with Burt, (2004) who found that cumin showed an antimicrobial effect against Staphylococcus aureus, Rassooliet al. (2006) and Sienkiewicz et al. (2011)who found that thyme essential oil is noted to possess bactericidal properties against S. aureus.

Enterococci have been considered harmless commensals. However, the opinion changed in view of the increasing number of nosocomial infections in humans caused by these organisms. These infections are due to intrinsic, and particularly in recent years, increasing acquired resistance to a number of antibiotics used for therapy. Enterococcus can be used as an indicator of both fecal contamination of foods and the dissemination of antimicrobial resistance related to the use of antimicrobials in farming Van den Bogaardet al. (2002).

^(a,b,c)Means on the same raws carrying different superscript small letters are significantly different (P< 0.05).

The data in table (4) declared significant decrease (p< 0.05) in Enterococcus count in garlic 1% treated group start from zero day and extend all over the storage days. On the other hand significant decreases in thyme 1% treated group start from 6^th day and in cumin 1% start from 9^th day   of storage when compared with control group. The reduction of bacterial counts may be attributed to the antimicrobial effect of different compounds in the essential oils. Antimicrobial activity of different essential oils is directly related to the presence of phenolic compounds, which are able to inhibit the growth of bacteria. Those active compounds of essential oils may interact with the bacterial cell membrane causing the leakage of its cellular components and accordingly cause the cell death (Raccach, 1984). The depleting of the proton motive force, changing phospholipid constituents and fatty acid, impairing enzymatic mechanisms used for energy production and metabolism, altering electron transport and nutrient uptake (Taniguchi et al., 1988).

In conclusion thyme and garlic oil at concentration 1% have the ability to minimize chemical changes and decrease bacterial load of chilled chicken burger. So, using of these oil in chicken burger formulation considered as a promising solution to be used instead of chemical preservative.

Table (4) Effect of essential oils on Enterococcus count in chicken burger strored at 3 ±1 ^OC (N=5).

^(a,b,c)Means on the same raws carrying different superscript small letters are significantly different (P< 0.05).

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تأثیر بعض الزیوت الأساسیة على جودة برجر الدجاج المحفوظة بالتبرید

محمد عبدالله حسین ، عبدالسلام الدیدامونى حافظ وریهام عبدالحمید جمعة

قسم مراقبة الأغذیة –کلیة الطب لبیطرى –جامعة الزقازیق

فى هذه الدراسة تم عمل أربع مجموعات من برجر الدجاج الأولى کمجموعة ضابطة ، والثانیة والثالثة والرابعة تحتوی على الزیوت الأساسیة للکمون ،الزعتر والثوم بترکیز 1٪ على التوالی. تمت دراسة تأثیر المعالجات المختلفة على الأس الهیدروجینی والمواد النیتروجنیة المتطایرة  وحمض الثیوباربیتریک والعدد الکلى للبکتریا الهوائیة  وعدد المکورات العنقودیة وعدد المکورات المعویة خلال أیام التبرید عند 3 ± 1 درجة مئویة. کانت متوسطات الأس الهیدروجینی والمواد النیتروجنیة المتطایرة  وحمض الثیوباربیتریک (7.21 ± 0.09 و 30.89 ± 3.64 مجم / 100 جم و 1.29 ± 0.04 مجم MDA / کجم) و (6.36 ± 0.06 و 16.76 ± 1.26 مجم / 100 جم و 0.98 ± 0.02 مجم MDA / کجم) ، (6.20 ± 0.07 ، 13.97 ± 1.34 مجم / 100 جم ، 0.76 ± 0.02 مجم MDA / کجم) و (6.13 ± 0.08 ، 12.81 ± 1.74 مجم / 100 جم ، 0.64 ± 0.02 مجم MDA / کجم) فی المجموعة الضابطة ، ، المجموعات المعالجة بالکمون والزعتر والثوم ، على التوالی فی الیوم التاسع من التبرید. ووجد أن متوسط القیم  للعدد الکلى للبکتریا الهوائیة  وعدد المکورات العنقودیة وعدد المکورات المعویة کانت (7.63 ± 0.46 و 5.03 ± 0.35 و 5.17 ± 0.31 لوغاریتم 10 مستعمرة بکتیریة /جم) و (6.92 ± 0.44 و 4.21 ± 0.31 و 4.34 ± 0.29 لوغاریتم 10 مستعمرة بکتیریة /جم) و (6.64 ± 0.43 و 4.14 ± 0.29 و 4.08 ± 0.24 لوغاریتم 10 مستعمرة بکتیریة /جم) و (6.31 ± 0.46 و 3.91 ± 0.27 و 3.97 ± 0.25 لوغاریتم 10 مستعمرة بکتیریة /جم) فی المجموعة الضابطة والکمون والزعتر والثوم ، على التوالی فی الیوم الثالث عشر من التبرید. أظهر زیت الثوم ترکیز 1٪ تأثیرات جیدة  فی تثبیط التغیرات الکیمیائیة وتقلیل نمو البکتیریا.