Usage of concentrated pomegranate to extend the shelf life of chicken breast

INTRODUCTION

Chicken meats continue to be the most significant foods consumed worldwide, itis a good source of protein with high biological value, vitamin A, thiamine, iron, phosphorus and nicotinic acid (Koblitz, 2011). Fresh meats are highly perishable and support the growth of pathogenic and spoilage microorganisms. Despite applying many controls and preventive measures, food-borne illnesses are still an important public health issue in both developing and non-developing countries (Zhou et al. 2010).

The fresh meat is very sensitive to spoilage by microbial growth and oxidative reactions. High level protein and moisture cause microbial spoilage of meat while the aerobic condition induces oxidation of lipid and protein. Decreasing microbial growth and delaying lipid and protein oxidation during storage can increase the shelf-life of meat (Vaithiyanathan et al. 2011).

It is known that chicken meat is a reservoir for a large number of bacteria that may be pathogenic to human. Typically, these occur at low levels of sanitation and may pose a threat to the consumer if the product is not treated in a safe manner (El-Fakhrany et al. 2019). The bacterial contamination and hygienic measures during meat production can be measured using the aerobic plate count and total Enterobacteriaceae (Hamed et al. 2015).

Nowadays, synthetic preservatives are being applied to prevent the microbial growth and as well as retarding the oxidation reactions in meat. The consumers are unsatisfied from various chemical preservatives because of their side effects such as carcinogenicity and teratogenicity. The excessive demand for natural preservatives results in their extended utility (Giatrakou  and Savvaidis 2012).

Acidification using organic acids and natural acidic fruit juices such as pomegranate juice is an extensively used method in food processing to extend the shelf-life (Sengun and Karapinar, 2004).

The pomegranate (Punicagranatum) is a well-known source of important nutrients. Because of its great nutritious value, antioxidant capacity, bioactive components, and consumer appeal, it is referred to be a "superfruit." It includes hydrolysable tannins, condensed tannins, flavonoids, anthocyanins, and phenolic and organic acid components, all of which have been linked to a variety of health advantages (Nuncio-Jáuregui et al. 2015). The  edible part of the fruit contains considerable amount of acids, sugars, vitamins, polysaccharides, polyphenols and important minerals (Vardin  and  Fenercioglu,  2003).

Pleasant flavor of pomegranate juice results from the combination of various taste, aroma and mouth feel sensations. The distinguished taste is due to mainly the presence of sugars (glucose and fructose) and organic acids (primarily citric and malic acids) (Vázquez Araújo et al. 2011). The great antioxidant potency from different components of pomegranate fruit such as juice, peel and seeds have been discovered (Gil et al. 2000).

The antioxidant activity of pomegranate juice is higher than other fruit juices and beverages (Seeram et al. 2008). This antioxidant activity is correlated to the high level of phenolic compounds, including anthocyanins (3-glucosides and 3,5-diglucosides of delphinidin, cyanidin, and pelargonidin), ellagic acid, punicalin, punicalagin, pedunculagin and various flavanols (Alighourchi et al.  2008).

Therefore, the objective of this study was toinspect effect of dipping of chicken breast meat in different concentrations of pomegranate juice solution (1%, 2% and  4% v/w) on the shelf life and sensory attributes of chicken meat stored at 4ºC for 12 days.

MATERIALS AND METHODS

Collection of samples:

The chicken meat samples were obtained from a local poultry slaughterhouse in Benha and Damanhur province, wrapped in a sterile polyethylene bags and transported to the laboratory in isolated boxes with cooling packs.

Chicken meat samples that have been proven to contain E. coli, Pseudomonas and Staphylococcus aureus will be used to study the effect of pomegranate juice (PJ) in three concentrations (1, 2, and 4%) on these microbes during storage at 4±1ºC for 12 days.

Preparation of pomegranate juice (PJ)

Fresh pomegranate fruits (Punicagranatum) were obtained from a local supermarket. The fruits were washed and cut into four pieces. The seeds/arils were manually separated and ground in amixer for 30 s and then passed through muslin cloth. After filtering by a Millipore filter with a 0.22 μm nylon membrane under vacuum at 25 °C, the freshly prepared PJ was sterilized by the high-pressure treatment and was stored at 4^oC until use, no more than 24 h later according to Bazargani-Gilani et al.(2015).

Preparation of chicken meat samples according to Vaithiyana than et al. (2011)

Twelve samples of chicken breast proved to be contaminated with E. Coli ˂10² cfu/g were divided into two groups; treated and control one. The treated groups were divided into 3 groups that were dipped in pomegranate juice (PJ) at concentration 1%,  2% and 4% for 15 minutes and then drained well for 5 minutes on a sterile stainless wire mesh screen. The same technique was applied for samples of chicken breast proved to be contaminated with pseudomonas and Staphylococcus aureus. Chicken breast were individually sealed in clean polyethylene bags and stored at 4 °C for up to 12 days. The treated and control samples stored at 4±1°C and examined regularly every 3 days at (zero, 3^rd, 6^th, 9^th and 12^th ) for sensory, chemical and microbiological parameters.

Sensory analysis according to Lawless and Heymann (2010).

Fifteen panelists individual (adult, untrained) were asked to assess the sensory qualities of chicken breast samples. The samples were blind–coded with special codes; the panelists were not informed about the experimental approach. They were asked to give a score for each of overall acceptance while the samples were fresh (uncooked). Nine-point descriptive scale was used. A score of 7–9 indicated ‘‘very good’’ quality, a score of 4.0–6.9 ‘‘good’’ quality, a score of 1.0–3.9 indicated as spoiled was used for the evaluation of appearance, tenderness, and flavor.

Chemical analysis of treated chicken meat:

Measurement of pH according to (ES 63-11/2006) was verified using a pH-meter (Digital, Jenco 609). The pH was measured by blending 10 g sample with 90 ml deionized water for 2 min. The pH of the obtained suspension was measured with a digital pH meter.

Measurement of Thiobarbituric acid reactive substance  (TBARS) according to (ES 63/9-2006). Ten grams of the sample were blended with 48 mL distilled water. Two ml of 4% ammonium chloride (to bring the pH to 1.5) was added to the previous contents in a warring blender for 2 min and left at room temperature for 10 min. The mixture was quantitatively transferred into Kjeldal flasks by washing with an additional 50 mL distilled water, followed by an antifoaming preparation and a few glass beads. The Kjeldal distillation apparatus was assembled and the flask was heated to 50 °C. Distillates were collected at 10 min from the time of the boiling commencing. The distillates (50 mL) were mixed, and then were pipette into a glass Stoppard tube. Then, 5 mL TBA reagent (0.2883/100 mL of glacial acetic acid) was added, the tube was stoppered, shacked and immersed in a boiling water bath for 35 min. A blank was similarly prepared using 5 mL distilled water with 5 mL of TBA reagent and treated like the sample. After heating, the tube was cooled under tap water for 10 min. A portion was transferred to a curette and the optical density (D) of the sample was read against the blank by means of a spectrophotometer (Perkin Elmer, 2380, USA) at a wave length of 538 nm. The TBA value (mg malondialdehyde /Kg of sample) = Dx7.8 D: the read of sample against blank.

Measurement of total volatile basic nitrogen (TVBN) according to method recommended by (ES 63/10-2006).Teng of the samples was mixed with 100 ml distilled water and washed into a distillation flask with 100 ml distilled water; then 2g of magnesium oxide and an antifoaming agent were added. The mixture was distilled using the micro Kjeldahl distillation apparatus. Distillate was collected for 25min into 25 ml 4% boric acid and five drops of Tashero indicator. The solution was titrated using (0.1 M) HCl to calculate the total volatile basic nitrogen in the sample in terms of mg VBN/100g meat

Microbiological analysis:

Preparation of serial dilution according to APHA (1992).

Chicken breast samples were firstly cauterized by using hot spatula (surface sterilization) then the cauterized parts were removed by using sterilized scalpel and forceps, then under complete aseptic conditions 25 grams of each sample were weighted and transferred into a sterile homogenizer flask contained 225 ml of (0.1%) peptone water. The content of each flask were homogenized at 14000 rpm for 2.5 minutes for obtaining a dilution of 10^-1, from which 1 ml was transferred with a sterile pipette to a sterile test tube containing 9 ml of (0.1%) peptone water, from which a decimal serial dilution were prepared in a sequential manner up to 10^-10, to cover all expected range of samples contamination. For microbial counts, colonies were counted and recorded in colony forming units per gram (cfu/g) of meat sampled using the formula:

cfu/g = level of dilution plated x number of colonies counted/volume plated.

These were further expressed in mean colony forming units pergram (mean cfu/g) and converted to log₁₀ base values (log₁₀cfu/g).

2.6.2. Total aerobic bacterial count was determined according to FDA, 2001using Plate count agar (pour technique) and was incubated for 48 ± 2 h at 35°C.

Enumeration of E.coli were determined according to ISO (16649-2:2001). Total E.colicount was carried out by pour plate method on TBX medium and incubated for 18 hours at 44ºC. E. coli produced blue colonies; the colonies were counted and expressed as CFU/g.

Pseudomonades were determined according to ISO 13720:2010 using pseudomonas agar base supplemented with cetrimide, fucidin, and cephaloridine, incubated spread plates at 25°C for 48 hours then examine for growth and fluorescence at 24 and 48 hours, using both white and UV light.

Staphylococcus aureus count were determined according to FDA (2001) on Baird Parker agar plate at 35^oC for 48 hours, suspected colony appeared as black, shiny colonies with halo zone around them were picked up for morphological examination and biochemical identification.

Statistical Analysis:

Triplicate samples (n = 3) were analyzed for each property. The results were expressed in terms of mean and stander deviation (SD) of mean. The means were compared by One Way ANOVA followed by Duncan’s Multiple Range Test (Duncan, 1955) using SPSS soft-ware version 17.0. Differences between means were determined by the least significant difference test, and significance was defined at P<0.05.