Quality and stability evaluation of chicken meat treated with gamma irradiation and turmeric powder

ABSTRACT

This study was carried out to evaluate the impact of gamma irradiation and turmeric powder (TP) on microbial quality (total aerobic bacteria and coliforms), physicochemical quality (pH, Hunter’s parameter, oxidative and microbial stabilities, haem pigment), stability, and antioxidant status of chicken meat. Accordingly, two doses (1 kGy and 2 kGy) of gamma irradiation alone and in combination with 3% TP along with the control (0 kGy) were applied. Aerobic and vacuum packaging were used for storage of chicken meat on the 0, 7th, and 14th days of storage at refrigeration temperature (4°C). The microbiological results showed that the contamination level decreased as the dose of gamma irradiation was increased for both total bacteria and coliforms, whereas no contamination was documented in the group treated with 2 kGy+TP for both aerobic and vacuum packaging. The results further showed that pH, haem pigment, and Hunter’s colour were also significantly influenced with respect to different groups. The peroxide value (POV), thio-barbituric acid reactive substances (TBARS), and total volatile basic nitrogen (TVBN) differed significantly in chicken meat with different treatments and storage intervals. Higher POV and TBARS were noticed in chicken meat treated with 2 kGy under aerobic packaging after 14 days of storage, and TVBN was higher in the control on the 14th day under aerobic packaging. Total phenolics and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity were also higher in chicken meat treated with 2 kGy + TP on 0 day of storage. Furthermore, higher sensory attribute scores for attributes like appearance, taste, texture, flavour, and overall acceptability were found in the 2 kGy-treated group. It is concluded that chicken meat treated with 2 kGy+TP was considered better for microbial and physicochemical quality, antioxidant activity as well as sensorial properties of chicken meat.

KEYWORDS:

• Gamma irradiation
• turmeric powder
• chicken meat
• antioxidant activity
• sensory evaluation

Introduction

Chicken meat is important worldwide due to the accessibility of nutrients like vitamins, essential amino acids, long-chain polyunsaturated fatty acids (PUFAs), and minerals. Meat and meat products can be contaminated from external sources during handling, bleeding, and processing. The contaminants on the knives will soon spread on various parts of the meat. Raw meat can be contaminated with different microorganisms, such as Salmonella spp, Escherichia coli, Listeria monocytogens, Streptococcus, and Micrococcus, and hence the control of meat pathogens is a vital safety issue.^[1]

Ionizing radiation technology shows potential as most of the problems that arise particularly by microbial spoilage and by the use of various chemical substances that pose potential health risks can be efficiently reduced by it, hence reducing the risks of food-borne disease outbreaks.^[2] Food irradiation eliminates or reduces the microbial population from food that are harmful for human health. It is a physical process involving the treatment of foods with ionizing radiation.^[3] The Food and Drug Administration (FDA) approved the forms of ionizing energies that can be used for food processing, including gamma rays (from 137-Cesium or 60-Cobalt), X-rays, and electron beams.^[4] Food preservation through radiation technology provides consumers with healthy and nutritious foods with improved safety, increased storage life, and quality and ease of transport.^[5]

The advantages of γ-radiation are basically its lethality, wide penetration power, and high energy content, as they act at the cellular level. It has uniform, deep, and instantaneous penetration ability.^[6] Cooked meat treated with the radiation process gives a strong flavour compared to cooked samples that are not treated with the radiation process.^[7] The recommended doses of gamma irradiation for chicken meat are up to 7 kGy for different types of meat. Salmonella spp. and other pathogens are easily decontaminated by the use of these doses. These recommended doses are sufficient for enhancing the shelf life of meat and meat products.^[8–10]

Irradiation produces some free radicals due to the radiolysis of water. These free radicals cause oxidation in the meat due to the fact that it is necessary to use native bioactive compounds along with the radiations.^[11] Turmeric, commonly known as “haldi” in the Indian subcontinent, contains a number of phyto-constituents, namely fat, protein, moisture, carbohydrates, and minerals in 5.1, 6.3, 13.1, 69.4, and 3.5%, respectively.^[12] Turmeric owes its characteristic yellow colour to three major pigments: curcumin (71.5%), demethoxy-curcumin (19.4%), and bis-demethoxycurcumin (9.1%).^[13] From the safety point of view, the FAO/WHO expert on food additives jointly authorized curcumin, the yellow colouring agent of turmeric, for this purpose.^[14] It represents about 3–5% of curcuminoids in the rhizomes of turmeric and is regarded as one of the strong phenolic antioxidants.^[15–17] It also benefits the nutrition of poultry, which include improvement in the parameters of broiler’s performance and the secretion of endogenous digestive enzymes and the activation of immune responses.^[18–20]

These plant extracts contend with synthetic drugs. Most medicinal plants have no residual effects.^[21] As the world becomes more advanced, animals and humans have started developing new diseases through the irrational use of antimicrobial and antibiotic growth promoters. This has led to increased numbers of works being carried out on medicinal plants. Hence, the evaluation of the fact on how different doses of gamma irradiation, combined with aerobic and vacuum packaging, influence the microbiological, physicochemical, and antioxidant parameters, along with the sensory attributes of chicken meat during storage, was the basic aim of this study.

Materials and methods

Materials

The chicken meat samples were purchased from a local market of Peshawar, Pakistan, from a freshly slaughtered chilled carcass and irradiated with gamma radiation at Nuclear Institute of Food and Agriculture (NIFA), Peshawar, 25000, Pakistan. The analyses were performed both at Institute of Home and Food Sciences, Government College University, Faisalabad and at NIFA, Peshawar. Chicken meat samples were aerobically packed using ziplock bags and a vacuum sealer used for vacuum packaging, and then these samples were stored at 4°C prior to use. All the chemicals and reagents being used in this study were purchased from well-known companies, including Sigma Aldrich (Tokyo) and Merck (Merck KGaA and Darmstadt, Germany). Three replicates were used in all parameters except in sensory, where there were seven trained panellists.

Gamma irradiation

Gamma irradiation was performed at NIFA, Peshawar, which is under the Pakistan Atomic Energy Commission. There were in total six groups with aerobic and vacuum packaging. Two doses (1 kGy and 2 kGy) of gamma irradiation were used alone and with a combination of 3% turmeric powder (TP) with the control (0 kGy).

Microbial quality

The microbial counts of the total viable bacteria (TVC) and the total coliforms in accordance with the guidelines of Association of Official Agricultural Chemists (AOAC) (2005) were performed and expressed as log CFU/g (CFU per gram). The samples of meat were placed in each enrichment broth, and then at the most favourable conditions, the samples were incubated.

Haem pigments

The haem pigments, for example, myoglobin (Mb), metmyoglobin (MMb), and oxy-myoglobin (MbO₂) relative concentrations, were determined according to the method described by Krzywicki.^[22]

Hunter’s colour

The surface colour values of the chicken samples treated and untreated with gamma irradiation with and without 3% TP were determined via a Hunter colorimeter, with the help of measurements that were standardized with respect to a white calibration plate (L = 89.2, a = 0.921, and b = 0.783). The CIE L* (lightness), CIE a* (redness), and CIE b* (yellowness) colour values, by using an average from nine random readings, were obtained on the surface of each sample for statistical analysis.

2-thio-arbituric acid reactive substances (TBARS) value

Using the method of TBARS explained earlier,^[23] with a few modifications, the extent of lipid oxidation was measured. The concentration of malonaldehyde was calculated using the following equation, where the values of TBARS are expressed as milligram (mg) malondialdehyde per kilogram (kg) meat:

$\mathrm{m}\mathrm{g}\mathrm{m}\mathrm{a}\mathrm{l}\mathrm{o}\mathrm{n}\mathrm{d}\mathrm{i}\mathrm{a}\mathrm{l}\mathrm{d}\mathrm{e}\mathrm{h}\mathrm{y}\mathrm{d}\mathrm{e}\mathrm{s}\mathrm{p}\mathrm{e}\mathrm{r}\mathrm{k}\mathrm{g}\mathrm{m}\mathrm{e}\mathrm{a}\mathrm{t}=\frac{\left(\mathrm{S}\mathrm{a}\mathrm{m}\mathrm{p}\mathrm{l}\mathrm{e}\mathrm{a}\mathrm{b}\mathrm{s}\mathrm{o}\mathrm{r}\mathrm{b}\mathrm{a}\mathrm{n}\mathrm{c}\mathrm{e}-\mathrm{b}\mathrm{l}\mathrm{a}\mathrm{n}\mathrm{k}\right)\times \mathrm{T}\mathrm{o}\mathrm{t}\mathrm{a}\mathrm{l}\mathrm{s}\mathrm{a}\mathrm{m}\mathrm{p}\mathrm{l}\mathrm{e}\mathrm{v}\mathrm{o}\mathrm{l}.}{0.000156\times 1000}$

Peroxide value (POV)

POV was determined according to the method of the International Dairy Federation (IDF).^[24]

Antioxidant potential

DPPH free radical scavenging activity

The irradiated and non-irradiated chicken meat samples with and without 3% TP were subjected to analysis of the DPPH radical scavenging activity according to the procedure outlined in.^[25] The inhibition of free radicals by DPPH in percent (%) was calculated using the following equation:

$\mathrm{I}\mathrm{n}\mathrm{h}\mathrm{i}\mathrm{b}\mathrm{i}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{n}\left(\mathrm{\%}\right)=100\times \left(\mathrm{A}\mathrm{b}\mathrm{l}\mathrm{a}\mathrm{n}\mathrm{k}-\mathrm{A}\mathrm{s}\mathrm{a}\mathrm{m}\mathrm{p}\mathrm{l}\mathrm{e}/\mathrm{A}\mathrm{b}\mathrm{l}\mathrm{a}\mathrm{n}\mathrm{k}\right)$

Total phenolic contents (TPCs)

The TPCs in chicken meat treated and untreated with and without gamma irradiation with 3% TP were determined by following the method described in.^[26]

TVBN

The TVBN values of the irradiated and non-irradiated chicken meat samples with and without 3% TP were measured. The TVBN value was calculated using the following equation:

${ }^{\prime \prime }{\mathrm{N}}^{\prime \prime }\mathrm{m}\mathrm{g}/\mathrm{m}\mathrm{L}\mathrm{o}\mathrm{f}\mathrm{e}\mathrm{x}\mathrm{t}\mathrm{r}\mathrm{a}\mathrm{c}\mathrm{t}=14\times \mathrm{a}\times \mathrm{b}$

TVBN value (mg/100 mL) = 100 × N, where 14 is the molecular weight of nitrogen, a is normality of H₂SO₄, and b is the volume of H₂SO₄ (titration value).

Sensory evaluation

Sensory evaluation of chicken turmeric patty treatments was carried out by a trained taste panel, employing a nine-point hedonic scale (9 = extremely liked; 1 = extremely disliked) by following the guidelines in.^[27] During the time of sensory evaluation, the panellists were given mineral water, unsalted crackers, and expectorant cups to neutralize and rinse their taste receptors for rational assessment. In total, 10 panellists were selected on the basis of their expertise in sensory evaluation.

Statistical analysis

The data obtained for different parameters were analysed statistically using the Statistical Package, Statistic 8.1. Levels of significance (p ≤ 0.05) were determined (analysis of variance, ANOVA) using three-factor factorial under completely randomized design (CRD) by following the principles outlined in.^[28] The means were compared using least significant difference (LSD). Three replicates were used for all parameters, except for sensory and Hunter’s colour. In Hunter’s colour, there were nine random readings, and 10 trained panellists were selected for the sensory scores.

Results and discussion

Microbial quality

The microbial counts for the total aerobic bacteria and coliforms in the untreated and treated samples of TP and gamma irradiation were analysed. With increase in the dose of gamma irradiation, the microbial populations decreased significantly; as the storage period increased, the microbial contamination increased in aerobic packaging, while compared to aerobic packaging, the microbial contamination decreased in vacuum packaging. The results showed an elevated count (10.44 ± 0.04 log CFU/g) of the total aerobic bacteria (TAB), and it was found in the untreated sample (0 kGy) on the 14th day of storage in aerobic packaging, while a lower TAB count of 2.71 ± 0.08 log CFU/g was found with the dose of 2 kGy of gamma irradiation in vacuum packaging on 0 day of storage, as shown in Table 1. The results represented that complete decontamination was attained with 2 kGy + TP of the dose during all storage intervals (0, 7, and 14 days) in both aerobic and vacuum packaging. A higher coliform count (5.39 ± 0.16 log CFU/g) was found in the untreated sample (0 kGy) on the 14th day of storage in aerobic packaging, whereas a lower coliform count of 2.65 ± 0.08 log CFU/g was obtained with the dose of 1 kGy of gamma irradiation on day 0 of storage in vacuum packaging. These results indicated that complete decontamination was achieved with the dose of 1 kGy + TP and 2 kGy + TP during all storage intervals (0, 7, and 14 days) in both aerobic and vacuum packaging. The results depicted that the treated chicken meat had higher values of TAB and coliforms in aerobic packaging as compared to vacuum packaging, while lower counts were found in the treated samples, which are in agreement with the findings of Montiel et al.;^[29] they reported that irradiation of 1 and 2 kGy doses significantly curtailed the total viable counts in smoked salmon by 2 and 2.4 log units, respectively. ^[30] reported that irradiation reduced the load of bacteria and improved the shelf life, which is in agreement with the results of our study. The results of our study are also in agreement with the outcomes of,^[31] who reported that irradiation at 5°C reduced the natural flora on chicken skin from 10⁴–10⁵ to 10–500 cells/7 cm^{2. [32]} also stated that an irradiation dose of 2.0 kGy or more inactivated 99% of the microbial loads on chicken carcasses. Another study showed that combined treatments using bioactive compounds (cinnamaldehyde + ascorbic acid (0.5%, w/w), cinnamaldehyde (1.47%, w/w), or cinnamaldehyde + sodium pyrophosphate deca hydrate (0.1%, w/w)) and irradiation can significantly reduce the microbial load of meat samples compared to untreated control samples.^[33]

Table 1. Total aerobic bacteria and coliforms of chicken meat treated with gamma irradiation and turmeric powder at different storage periods (0, 7th, and 14th days)

		Storage period (days)
		0		7		14
Parameter	Treatments	Aerobic	Vacuum	Aerobic	Vacuum	Aerobic	Vacuum
Total Aerobic Bacteria (log CFU/g)	0 kGy	8.36 ± 0.11a	7.28 ± 0.24a	9.34 ± 0.29a	8.11 ± 0.06a	10.44 ± 0.04a	9.35 ± 0.07a
	1 kGy	5.49 ± 0.32c	4.74 ± 0.51c	6.37 ± 0.38c	5.32 ± 0.36c	6.95 ± 0.01c	6.74 ± 0.40c
	2 kGy	3.22 ± 0.09e	2.71 ± 0.08d	4.86 ± 0.28e	3.55 ± 0.38d	5.14 ± 0.3e	4.21 ± 0.80d
	0 kGy +TP	6.38 ± 0.21b	5.14 ± 0.51b	7.36 ± 0.44b	6.25 ± 0.21b	8.35 ± 0.22b	7.36 ± 0.39b
	1 kGy + TP	4.12 ± 0.39d	ND	5.41 ± 0.41d	3.47 ± 0.6d	6.36 ± 0.19d	4.65 ± 0.04cd
	2 kGy + TP	ND	ND	ND	ND	ND	ND
Coliforms (log CFU/g)	0 kGy	4.65 ± 0.07a	3.54 ± 0.10a	4.89 ± 0.11a	3.69 ± 0.42a	5.39 ± 0.16a	4.11 ± 0.25a
	1 kGy	3.22 ± 0.15c	2.65 ± 0.08c	3.77 ± 0.22c	2.99 ± 0.31c	4.01 ± 0.15c	3.65 ± 0.28c
	2 kGy	2.88 ± 0.16d	ND	3.65 ± 0.08c	ND	3.77 ± 0.07d	ND
	0 kGy + TP	3.87 ± 0.24b	3.11 ± 0.09b	4.31 ± 0.04b	3.44 ± 0.25b	4.73 ± 0.37b	3.75 ± 0.09b
	1 kGy + TP	ND	ND	ND	ND	ND	ND
	2 kGy + TP	ND	ND	ND	ND	ND	ND

TP, turmeric powder; ND, not detected

The values are mean ±SD of three independent determinations

Means carrying different letters in rows or columns differed significantly

Physicochemical assay

Haem pigment

The statistical results regarding the Mb content of chicken meat samples have a significant effect with respect to treatments and storage interval. Higher Mb content (39.65 ± 2.71%) was observed in treated (1 kGy + TP) vacuum-packaged samples on 0 day of storage, followed by aerobic-packaged treated (0 kGy +TP) chicken meat samples (39.64 ± 2.71%) on 0 day, whereas minimum content (6.15 ± 0.93%) was noticed in the vacuum-packaged samples treated with 1 kGy on the 14th day of storage, as listed in Table 2. The results showed that the Mb content significantly decreased in vacuum-packaged chicken meat samples as compared to aerobic samples. Moreover, the Mb content of untreated chicken samples (control) lessened gradually. Mb present in the treated and untreated chicken meat samples also increased with the addition of TP in both aerobic- and vacuum-packaged samples.

Table 2. Haem pigment of chicken meat treated with gamma irradiation and turmeric powder at different storage periods (0, 7th, and 14th days)

		Storage period (days)
		0			7			14
Parameter	Treatments	Aerobic	Vacuum	Means	Aerobic	Vacuum	Means	Aerobic	Vacuum	Means
Myoglobin (%)	0 kGy	38.93 ± 2.64	37.69 ± 2.15	38.31 ± 1.50a	19.89 ± 2.74	18.61 ± 1.14	19.25 ± 1.80b	7.94 ± 0.80	6.62 ± 0.70	7.28 ± 0.71c
	1 kGy	37.95 ± 2.24	37.25 ± 2.30	37.60 ± 1.80a	18.75 ± 1.25	18.19 ± 0.98	18.47 ± 1.40b	6.82 ± 0.72	6.15 ± 0.93	6.48 ± 0.04c
	2 kGy	37.63 ± 2.10	38.47 ± 2.41	38.05 ± 0.40a	18.54 ± 1.24	19.31 ± 2.70	18.92 ± 0.70b	6.59 ± 0.73	7.45 ± 0.94	7.01 ± 0.07c
	0 kGy +TP	39.64 ± 2.71	38.97 ± 2.67	39.30 ± 1.30a	20.57 ± 2.10	19.98 ± 1.58	20.27 ± 0.30b	8.51 ± 0.83	7.99 ± 0.76	8.25 ± 0.40c
	1 kGy + TP	38.55 ± 2.27	39.65 ± 2.71	39.10 ± 2.10a	19.48 ± 2.47	20.60 ± 2.11	20.04 ± 0.64b	7.87 ± 0.76	8.60 ± 0.89	8.23 ± 0.90c
	2 kGy + TP	37.49 ± 2.29	39.44 ± 2.65	38.46 ± 1.00a	18.38 ± 1.33	20.41 ± 1.94	19.39 ± 1.50b	6.22 ± 0.71	8.41 ± 0.94	7.31 ± 1.40c
	Means	38.36 ± 0.50a	38.57 ± 0.07a		19.26 ± 1.00b	19.51 ± 1.50b		7.32 ± 1.160c	7.53 ± 1.14c
Oxymyoglobin (%)	0 kGy	13.31 ± 0.95	12.43 ± 1.17	12.87 ± 1.18hi	16.25 ± 2.03	15.52 ± 2.42	15.88 ± 0.08def	21.45 ± 1.09	20.90 ± 1.55	21.17 ± 1.50abc
	1 kGy	14.32 ± 1.33	12.66 ± 1.18	13.49 ± 1.19ghi	17.59 ± 2.14	15.79 ± 1.99	16.68 ± 1.70de	22.63 ± 2.31	20.99 ± 1.44	21.81 ± 1.90ab
	2 kGy	14.97 ± 1.49	13.66 ± 0.80	14.31f±0.07fgh	17.98 ± 1.97	16.58 ± 1.58	17.28 ± 1.10d	22.87 ± 2.39	21.69 ± 1.10	22.28 ± 1.10a
	0 kGy + TP	12.37 ± 1.17	11.02 ± 1.24	11.69 ± 0.02i	15.45 ± 2.15	14.14 ± 1.47	14.79 ± 1.80efgh	20.79 ± 1.51	19.22 ± 2.19	20.00 ± 0.20bc
	1 kGy + TP	12.34 ± 1.17	11.39 ± 1.12	11.86 ± 0.10i	15.40 ± 2.15	14.47 ± 1.98	14.93 ± 1.20efg	20.51 ± 1.96	19.40 ± 2.06	19.95 ± 0.44bc
	2 kGy + TP	11.44 ± 1.10	11.99 ± 1.02	11.71 ± 0.06i	14.58 ± 1.52	14.89 ± 1.53	14.73 ± 1.00fgh	19.64 ± 2.44	19.90 ± 1.66	19.77 ± 1.55c
	Means	13.12 ± 1.70c	12.19 ± 1.20c		16.20 ± 1.10b	15.23 ± 1.70b		21.31 ± 1.80a	20.34 ± 1.10a
Metmyoglobin (%)	0 kGy	41.12 ± 2.51	38.65 ± 1.93	39.78 ± 1.4 ± 0.70gh	52.24 ± 3.21	49.04 ± 3.43	50.63 ± 1.12de	62.73 ± 4.02	59.73 ± 3.07	61.23 ± 0.09ab
	1 kGy	44.64 ± 2.22	40.21 ± 2.10	42.42 ± 1.2 ± 0.09g	54.27 ± 3.46	51.54 ± 3.23	52.90 ± 1.19d	65.50 ± 3.99	61.28 ± 3.19	63.39 ± 0.08a
	2 kGy	44.99 ± 2.45	40.98 ± 2.51	42.98 ± 0.2 ± 1.80g	54.80 ± 3.56	51.99 ± 2.72	53.39 ± 1.60d	65.98 ± 3.55	61.70 ± 2.83	63.83 ± 1.7a
	0 kGy + TP	37.36 ± 1.75	35.24 ± 1.22	36.30 ± 0.8 ± 1.60i	48.26 ± 3.60	45.16 ± 2.56	46.71 ± 1.80f	58.43 ± 2.68	56.14 ± 3.38	57.28 ± 1.8c
	1 kGy + TP	36.47 ± 1.42	35.91 ± 1.43	36.18 ± 0.90i	47.41 ± 2.95	45.86 ± 2.68	46.63 ± 1.50f	60.57 ± 3.03	56.61 ± 3.32	58.58 ± 1.12bc
	2 kGy + TP	36.82 ± 1.62	36.41 ± 1.32	36.61 ± 0.70hi	47.94 ± 2.46	47.30 ± 2.62	47.62 ± 0.40ef	60.98 ± 3.03	60.22 ± 3.40	60.60 ± 1.9ab
	Means	40.19 ± 0.08e	37.89 ± 1.00f		50.81 ± 0.80c	48.48 ± 1.51d		62.36 ± 1.80a	59.28 ± 0.40b

TP, turmeric powder

The values are mean ±SD of three independent determinations

Means carrying different letters in rows or columns differed significantly

The results showed that the MbO₂ contents of treated and untreated chicken samples ranged from 11.44 ± 1.10% to 14.97 ± 1.49% and 11.02 ± 1.24% to 13.66 ± 0.80% in aerobic and vacuum packaging, respectively, on 0 day of storage, whereas in the treated and untreated chicken samples at the end of the storage interval (14 days) the values ranged from 19.64 ± 2.44% to 22.87 ± 2.39% and 19.22 ± 2.19% to 21.69 ± 1.10% in aerobic and vacuum packaging, respectively. Higher value of MbO₂ (22.87 ± 2.39%) was observed in treated (2 kGy) aerobic-packaged samples on the 14th day of storage, followed by vacuum-packaged treated (2 kGy) chicken meat samples (21.69 ± 1.10%) on the 14th day, whereas minimum value (11.02 ± 1.24%) was revealed in vacuum-packaged samples that were treated with 0 kGy + TP on 0 day of storage. The results depicted that the MbO₂ content significantly decreased in vacuum-packaged chicken meat samples as compared to aerobic samples. Furthermore, the MbO₂ in untreated chicken samples (control) increased with the passage of time. The MbO₂ contents in treated and untreated chicken meat samples also decreased with the addition of TP in both aerobic- and vacuum-packaged samples.

Higher value of MMb (65.98 ± 3.55%) was observed in treated (2 kGy) aerobic-packaged samples on the 14th day of storage, followed by vacuum-packaged treated (2 kGy) chicken meat samples (61.70 ± 2.83%) on the 14th day, whereas minimum value (35.24 ± 1.22%) was found in the vacuum-packaged samples treated with 0 kGy + TP on 0 day of storage. The results revealed that the MMb content significantly decreased in vacuum-packaged chicken meat samples as compared to aerobic samples. Moreover, the MMb in untreated chicken samples (control) increased with the passage of time. The MMb contents in treated and untreated chicken meat samples also decreased with the addition of TP in both aerobic- and vacuum-packaged samples.

The results showed that the treated samples of chicken meat have a lower content of Mb in aerobic packaging, but in the cases of MbO₂ and MMb, lower contents were found in vacuum packaging; however, a higher content of Mb was found in the untreated sample (control), and in MbO₂ and MMb, higher contents were found in treated samples, which is agreement with the findings of,^[30] who reported that a higher level of Mb was found in the control samples on 0 day under aerobic packaging, but at 4.5 kGy the lowest level was found. In the samples that were irradiated with 4.5 kGy, higher levels of MbO₂ and MMb were found on the 40th day of storage under aerobic packaging, while in the non-irradiated control sample (0 kGy), low levels of MbO₂ and MMb were found on 0 day. Our results are in agreement with the outcomes of,^[34] who reported that with the passage of time and increase in the level of dose via an intermediate MbO₂ phase, the Mb oxidized into MMb. There are numerous mechanisms that are responsible for the pro-oxidant capacities of Mb’s, for instance, the ability to decompose hydro-peroxide, and because of the conversion to the ferryl/perferryl form, they can serve as a free radical. Hydrogen peroxide and superoxide anions are produced by the oxidation process, which in turn, after reacting with iron (Fe), generate hydroxyl radicals. These hydroxyl radicals, after diffusing with the hydrophobic lipid region of the muscles, facilitate the oxidation of lipids. The hydroxyl radicals that were produced from water due to ionizing radiation convert the Mb into MMb or even serve as a catalyst to eliminate the ferric ion haem and speed up the oxidation of lipids.^[35,36]

Hunter’s colour

The statistical results regarding the L* value of chicken meat samples have a significant effect with respect to treatments and packaging. Higher value of L* (56.12 ± 2.02) was observed in treated (0 kGy + TP) aerobic-packaged samples on the 14th day of storage, followed by vacuum-packaged treated (0 kGy + TP) chicken meat samples (53.44 ± 3.16) on the 14th day, whereas minimum value (49.11 ± 2.51) was found in the vacuum-packaged samples treated with an irradiation dose of 1 kGy on 0 day of storage, as listed in Table 3. The results described that the L* value significantly decreased in vacuum-packaged chicken meat samples as compared to aerobic samples. Furthermore, the L* value in untreated chicken samples (control) increased with the passage of time. The L* values in treated and untreated chicken meat samples also increased with the addition of TP in both aerobic- and vacuum-packaged samples. The results showed that the treated sample of chicken meat has a higher value of L* in aerobic packaging, while a lower value was found in treated samples. Our results are in accordance with the outcomes of,^[37] who stated that as the dose was increased from 0 to 4 kGy, the L* values of irradiated pork jerky also increased. It was reported by^[33] that the L* value increased as the irradiation dose was increased in ground beef. Likewise,^[38] the addition of citric or ascorbic acid increased the L* values of irradiated meat, resulting in lighter overall colour impression to meat. In agreement with these findings, significantly higher values of L* in beef steaks treated with lactic acid and clove oil were reported by.^[39]

Table 3. Hunter’s colour of chicken meat treated with gamma irradiation and turmeric powder at different storage periods (0, 7th and 14th days)

		Storage period (days)
		0			7			14
Parameter	Treatments	Aerobic	Vacuum	Means	Aerobic	Vacuum	Means	Aerobic	Vacuum	Means
L*	0 kGy	51.22 ± 3.05	49.22 ± 3.20	50.21 ± 0.80b	51.45 ± 2.79	49.70 ± 2.25	50.57 ± 1.9b	51.77 ± 2.33	50.12 ± 2.65	52.61 ± 1.74ab
	1 kGy	50.77 ± 2.94	49.11 ± 2.51	49.94 ± 0.60b	50.81 ± 3.35	49.20 ± 3.34	50.00 ± 1.16b	50.88 ± 3.33	49.47 ± 3.01	50.17 ± 1.10b
	2 kGy	51.12 ± 3.59	49.44 ± 3.84	50.28 ± 1.00b	51.31 ± 1.76	49.35 ± 3.05	50.32 ± 1.18b	51.55 ± 3.07	49.55 ± 2.92	50.55 ± 1.41b
	0 kGy +TP	53.77 ± 3.20	52.12 ± 2.57	52.94 ± 1.20ab	54.12 ± 3.04	52.09 ± 3.51	53.10 ± 1.02ab	56.12 ± 2.02	53.44 ± 3.16	54.78 ± 1.65a
	1 kGy + TP	52.44 ± 3.04	50.19 ± 2.13	51.31 ± 1.18b	52.78 ± 3.07	51.11 ± 1.85	51.94 ± 1.17ab	53.92 ± 3.32	52.47 ± 3.01	53.19 ± 1.54ab
	2 kGy + TP	52.19 ± 2.09	50.12 ± 2.65	51.15 ± 1.70b	52.63 ± 3.17	51.44 ± 2.81	52.03 ± 1.19ab	52.99 ± 3.28	52.78 ± 3.07	52.88 ± 1.00ab
	Means	51.91 ± 1.16abc	50.03 ± 1.18c		52.18 ± 1.10ab	50.48 ± 1.17bc		53.42 ± 1.10a	51.30 ± 1.17bc
a*	0 kGy	11.19 ± 0.57	12.72 ± 1.00	11.95 ± 0.02d	10.77 ± 1.21	13.22 ± 0.96	11.99 ± 1.14d	10.52 ± 1.19	13.77 ± 1.14	12.14 ± 1.13d
	1 kGy	11.32 ± 0.88	12.91 ± 1.07	12.11 ± 0.7d	10.91 ± 1.29	13.98 ± 1.28	12.44 ± 1.90d	10.61 ± 1.14	14.47 ± 0.89	12.53 ± 1.18d
	2 kGy	11.78 ± 1.05	13.01 ± 1.46	12.39 ± 0.1d	11.07 ± 1.86	14.21 ± 0.79	12.63 ± 1.60d	10.69 ± 0.96	15.11 ± 0.55	12.90 ± 1.00cd
	0 kGy + TP	14.12 ± 0.98	14.34 ± 1.15	14.23 ± 0.7ab	13.19 ± 1.04	15.22 ± 0.71	14.20 ± 1.90abc	12.42 ± 1.33	15.56 ± 0.63	13.98 ± 0.10bc
	1 kGy + TP	14.44 ± 1.54	15.07 ± 1.76	14.75 ± 1.12ab	14.01 ± 1.27	15.88 ± 1.66	14.94 ± 1.05ab	13.72 ± 1.25	16.11 ± 1.43	14.91 ± 0.24ab
	2 kGy + TP	14.79 ± 1.00	15.45 ± 0.65	15.12 ± 1.17ab	14.43 ± 0.97	16.26 ± 0.73	15.34 ± 0.80a	14.02 ± 1.28	16.43 ± 0.94	15.22 ± 0.70ab
	Means	12.94 ± 1.15c	13.91 ± 1.00b		12.39 ± 1.10cd	14.79 ± 0.80a		11.99 ± 0.50d	15.24 ± 1.10a
*	0 kGy	8.21 ± 1.54	6.66 ± 0.62	7.43 ± 2.0b	8.11 ± 0.93	6.41 ± 1.20	7.26 ± 1.17b	8.05 ± 0.98	6.39 ± 0.91	7.22 ± 0.05b
	1 kGy	8.35 ± 0.88	6.71 ± 1.16	7.53 ± 1.5b	8.44 ± 0.81	6.91 ± 1.37	7.42 ± 1.0b	8.57 ± 1.02	6.94 ± 1.09	7.75 ± 0.04b
	2 kGy	8.55 ± 1.60	6.92 ± 1.59	7.73 ± 1.05b	8.63 ± 1.03	6.98 ± 1.36	7.80 ± 1.14b	8.77 ± 0.88	7.06 ± 1.02	7.91 ± 1.0b
	0 kGy + TP	13.44 ± 1.47	10.11 ± 1.11	11.77 ± 1.7a	13.21 ± 1.53	9.92 ± 0.71	11.56 ± 1.0a	13.14 ± 1.49	9.87 ± 1.28	11.46 ± 1.2a
	1 kGy + TP	13.71 ± 1.24	10.43 ± 1.20	12.16 ± 1.14a	13.84 ± 1.57	10.72 ± 1.17	12.28 ± 1.16a	13.88 ± 0.90	10.91 ± 0.37	12.39 ± 1.5a
	2 kGy + TP	13.82 ± 1.58	10.55 ± 2.04	12.18 ± 1.80a	13.86 ± 1.57	10.84 ± 1.33	12.34 ± 1.14a	13.91 ± 0.91	10.92 ± 1.03	12.41 ± 1.9a
	Means	11.04 ± 0.50a	8.56 ± 1.10b		11.01 ± 1.80a	8.54 ± 1.14b		11.04 ± 1.19a	8.68 ± 1.10b

TP, turmeric powder

The values are mean ±SD of three independent determinations

Means carrying different letters in rows or columns differed significantly

The statistical results regarding the a* value of chicken meat samples have significant effects with respect to treatments and packaging. Higher value of a* (14.79 ± 1.00) was observed in treated (2 kGy + TP) aerobic-packaged samples on 0 day of storage, followed by vacuum-packaged treated (2 kGy + TP) chicken meat samples (16.43 ± 0.94) on the 14th day, whereas minimum value (10.52 ± 1.19) was found in the untreated (0 kGy) aerobic-packaged samples on the 14th day of storage. The results represented that the a* value significantly increased in vacuum-packaged chicken meat samples as compared to aerobic samples. Moreover, with the passage of time, the a* value in untreated chicken samples (control) decreased. The a* values of the treated and untreated chicken meat samples also increased with the addition of TP in both aerobic- and vacuum-packaged samples. The results showed that treated chicken meat has a higher value of a* in vacuum packaging, and a lower value was found in untreated (control) samples. ^[40] reported that the a* value (redness) of poultry breast was increased by irradiation in both aerobic- and vacuum-packaged systems. Our results agreed with the findings of,^[38] who reported that the raw breast meat of chicken and turkey treated with irradiation had increased redness (a*). ^[41] noted that the combined effect of chitosan and rosemary extract improved the redness of beef burger during frozen storage and improved colour stability using chitosan or rosemary extract alone compared to the control. The results are in line with another study, use of plum sliced increased shear force values, cook loss and redness (a*values) in ham.^[42]

The results showed that statistical results regarding the b* value of chicken meat samples have significant effects with respect to treatments and packaging. Higher value of b* (13.91 ± 0.91) was observed in treated (2 kGy + TP) aerobic-packaged samples on the 14th day of storage, followed by vacuum-packaged treated (2 kGy + TP) chicken meat samples (10.92 ± 1.03) on day 14; however, minimum value (6.39 ± 0.91) was found in untreated (0 kGy) vacuum-packaged samples on day 14 of storage. The results showed that the b* value significantly decreased in vacuum-packaged chicken meat samples as compared to aerobic samples. Furthermore, the b* value in untreated chicken samples (control) decreased gradually. The b* values in treated and untreated chicken meat samples also increased with the addition of TP in both aerobic- and vacuum-packaged samples. The results showed that the treated samples of chicken meat have a lower value of b* in vacuum packaging and a higher value was found in treated samples, in agreement with the results in,^[43] who showed that combined treatment of meat with ionizing radiation and citric acid positively affected the values of L* and b*. It was reported by^[37] that as the dose was increased from 0 to 4 kGy, the b* values of the irradiated pork jerky also increased. Our results agreed with the outcomes of^[44] that the b* (yellowness) value changes with no specific pattern in poultry products by any treatment (a combination of chitosan and thyme oil). Further studies that corroborate the results of the present study included the work of,^[45] who showed that the b* values in samples treated with Herbalox® were different from those of the control. The yellow value (b*) increased compared with the control. During the four-month storage period, the b* value of the GSE-containing sample decreased slightly. However, no uniform pattern of change was observed for the antioxidant or storage time effect.^[46]

Thiobarbituric acid reactive substances (TBARS)

The results regarding the TBARS value of chicken meat samples have significant effects with respect to treatments, packaging, and storage interval. Higher value of TBARS (0.66 ± 0.04 MDA/kg) was observed in treated (2 kGy) aerobic-packaged samples on day 14 of storage, followed by vacuum-packaged treated (2 kGy) chicken meat samples (0.63 ± 0.04 MDA/kg) on day 14, whereas the minimum value (0.32 ± 0.04 MDA/kg) was obtained for the vacuum-packaged samples treated with 0 kGy + TP on 0 day of storage, as listed in Table 4. The results depicted that the TBARS value significantly decreased in vacuum-packaged chicken meat samples as compared to aerobic samples. Besides, the TBARS value in untreated chicken samples (control) increased with the passage of time. The TBARS values in treated and untreated chicken meat samples also decreased with the addition of TP in both aerobic- and vacuum-packaged samples. The results depicted that the treated chicken meat had higher values of TBARS in aerobic packaging, while a lower value was found in untreated (control) samples. ^[47] stated that an increase in the irradiation dose in Atlantic salmon fillets from 0.5 to 3 kGy, stored at a temperature of 4°C, led to a significant increase in the TBARS value, which was in agreement with the results of our study. The results of this study were also in agreement with the results of^[48] and^[49] that only under the aerobic packaging conditions, the irradiation can increase the TBARS in cooked and raw meat. Under aerobic conditions, TBARS had a strong link to the content of total volatiles, ketones, and aldehydes in irradiated meat, but is not related to volatiles under vacuum conditions. Another study demonstrated that due to the antioxidant properties of ascorbic acid, it significantly reduced the TBARS value from 0.24 ± 0.01 mg/kg to 0.68 ± 0.05 mg/kg. There was 38% less abundance of the TBARS value of the combined effect of meat treated with a dose of 2 kGy and cinnamaldehyde + ascorbic acid as compared to meat that was only irradiated.^{[33] [50]} depicted that the peroxide value and TBARS values were further increased at the end of the storage period in beef burger steaks. The TBARS values of the 3% water-soluble yellow pigment extracted from turmeric with the irradiated samples were slightly increased when measured up to the control samples.

Table 4. Thiobarbituric acid reactive substances (TBARS) and peroxide value (POV) value of chicken meat treated with gamma irradiation and turmeric powder at different storage periods (0, 7th, and 14th days)

		Storage period (days)
		0			7			14
Parameter	Treatments	Aerobic	Vacuum	Means	Aerobic	Vacuum	Means	Aerobic	Vacuum	Means
TBARS (MDA/kg)	0 kGy	0.42 ± 0.03	0.37 ± 0.02	0.39 ± 0.05jkl	0.49 ± 0.03	0.40 ± 0.01	0.44 ± 1.20fgh	0.56 ± 0.03	0.45 ± 0.01	0.50 ± 1.80d
	1 kGy	0.49 ± 0.04	0.41 ± 0.04	0.44 ± 0.09fg	0.54 ± 0.02	0.44 ± 0.03	0.49 ± 1.80de	0.59 ± 0.03	0.49 ± 0.02	0.54 ± 0.47c
	2 kGy	0.56 ± 0.03	0.52 ± 0.01	0.53 ± 1.00c	0.61 ± 0.04	0.57 ± 0.02	0.58 ± 1.60b	0.66 ± 0.04	0.63 ± 0.04	0.64 ± 1.00a
	0 kGy +TP	0.34 ± 0.01	0.32 ± 0.04	0.32 ± 0.50m	0.38 ± 0.03	0.35 ± 0.01	0.36 ± 0.2l	0.43 ± 0.01	0.39 ± 0.02	0.40 ± 1.80ijk
	1 kGy + TP	0.41 ± 0.02	0.35 ± 0.03	0.38 ± 0.70kl	0.44 ± 0.01	0.39 ± 0.04	0.41 ± 1.70hij	0.49 ± 0.02	0.45 ± 0.03	0.46 ± 1.17ef
	2 kGy + TP	0.47 ± 0.04	0.40 ± 0.02	0.43 ± 1.70ghi	0.52 ± 0.04	0.44 ± 0.03	0.48 ± 1.00de	0.59 ± 0.02	0.51 ± 0.01	0.55 ± 1.14c
	Means	0.44 ± 1.20c	0.39 ± 1.80d		0.49 ± 1.12b	0.43 ± 1.60c		0.55 ± 1.10a	0.48 ± 1.14b
POV (meq peroxide/kg)	0 kGy	0.31 ± 0.02	0.29 ± 0.03	0.29 ± 1.0l	0.36 ± 0.02	0.33 ± 0.04	0.34 ± 0.20ijk	0.43 ± 0.04	0.38 ± 0.03	0.40 ± 1.02def
	1 kGy	0.39 ± 0.04	0.36 ± 0.02	0.37f±1.50fgh	0.44 ± 0.01	0.35 ± 0.02	0.39 ± 0.80efg	0.49 ± 0.02	0.41 ± 0.02	0.45 ± 1.50bc
	2 kGy	0.45 ± 0.03	0.42 ± 0.04	0.43 ± 0.50cd	0.53 ± 0.04	0.40 ± 0.02	0.46 ± 0.01b	0.59 ± 0.02	0.46 ± 0.03	0.52 ± 0.80a
	0 kGy + TP	0.27 ± 0.01	0.26 ± 0.01	0.26 ± 0.09m	0.33 ± 0.03	0.30 ± 0.03	0.31 ± 0.09kl	0.38 ± 0.03	0.34 ± 0.01	0.35 ± 0.40hij
	1 kGy + TP	0.35 ± 0.03	0.31 ± 0.01	0.33 ± 0.70jk	0.38 ± 0.03	0.35 ± 0.01	0.36 ± 1.00ghi	0.44 ± 0.01	0.39 ± 0.04	0.41 ± 1.60de
	2 kGy + TP	0.41 ± 0.02	0.35 ± 0.03	0.38 ± 0.01fgh	0.45 ± 0.04	0.39 ± 0.04	0.41 ± 1.20de	0.51 ± 0.04	0.45 ± 0.04	0.48 ± 1.00b
	Means	0.36 ± 0.20c	0.33 ± 0.80d		0.41 ± 0.01b	0.35 ± 1.24c		0.47 ± 1.12a	0.40 ± 0.87b

TP, turmeric powder

The values are mean ±SD of three independent determinations

Means carrying different letters in rows or columns differed significantly

Peroxide value

The results pertaining to the POV of the meat samples of chicken have significant effects with respect to treatments, packaging, and storage interval. Higher POV (0.59 ± 0.02 meq peroxide/kg) was observed in treated (2 kGy) aerobic-packaged samples on the 14th day of storage, followed by vacuum-packaged treated (2 kGy) chicken meat samples (0.46 ± 0.03 meq peroxide/kg) on day 14, whereas a minimum value (0.26 ± 0.01 meq peroxide/kg) was observed in the vacuum-packaged samples treated with 0 kGy + TP on day 0, as listed in Table 4. The results depicted that the POV significantly decreased in vacuum-packaged chicken meat samples as compared to aerobic samples. Furthermore, the POV in untreated chicken samples (control) increased with the passage of time. The POV in treated and untreated chicken meat samples also decreased with the addition of TP in both aerobic- and vacuum-packaged samples. The results indicated that the treated sample of chicken meat had a lower value in vacuum packaging and higher POV in treated samples, which is in agreement with the results of,^[37] who stated that similar to the value of TBARS, with an increase in the dosage of irradiation and expanded storage intervals, POV also increased. Our results concur with other studies indicating the increases in the levels of hydroxyl radicals following irradiation due to the radiolysis of water. Another study reported the strong suppression of lipid oxidation (both PV and TBARS) by hydrolysed potato protein in cooked beef patties.^{[51] [52]} also reported that antioxidant activity possessed by natural agents in the marinades, improve the quality of the beef and reduce POV throughout the storage period as compared to the control. Studies of^[53] provide further corroboration, who concluded that reduction in POVs with cassia essential oil was observed in deep-fat-fried beef as compared to the control.

Antioxidant potential

DPPH free radical scavenging activity

The results regarding the DPPH value of chicken meat samples have significant effects with respect to treatments, packaging, and storage interval. Higher value of DPPH (81.00 ± 1.58%) was observed in treated (0 kGy + TP) vacuum-packaged samples on day 0 of storage, followed by aerobic-packaged treated (0 kGy +TP) chicken meat samples (76.00 ± 2.51%) on day 0, while minimum value (51.00 ± 1.16%) was observed in the aerobic-packaged samples treated with 2 kGy on the 14th day of storage (Table 5). The results indicated that the DPPH value significantly increased in vacuum-packaged chicken meat samples as compared to aerobic samples. Moreover, with the passage of time, the DPPH value in untreated chicken samples (control) also decreased. Also in the treated and untreated chicken meat samples, the DPPH value increased with the addition of TP in both aerobic- and vacuum-packaged samples. The result showed that the treated chicken meat had a lower value of DPPH in aerobic packaging, while a higher value of DPPH was found in untreated (control) samples. ^[54] reported that the extract of Bidenspilosa leaf exhibited higher antiradical activity against 2,2-diphenyl-2-picrylhydrazyl (DPPH) and radicals of 2,2íazino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) than Moringaoleifera leaf extract and standard butylated hydroxy toluene (BHT) fresh ground beef during 6 days of cold storage. In the DPPH assay, the highest antioxidant activities (expressed as μ mol TE/g) were observed for S. aromaticum (8.19 ± 0.12) and C. cassia (6.36 ± 0.17) extracts, followed by B. nigra (4.80 ± 0.12) and O. vulgare (3.30 ± 0.09) in raw chicken meat.^[55] Another study demonstrated that chicken nuggets containing the antioxidants alpha lipoic acid and alpha tocopherol acetate retain higher percentage of DPPH inhibition all through the storage duration.^[56] The result of our findings is also in accordance with the results reported by^[57] and;^[58] they reported that the antiradical power was increased by these extracts (sage and vitamin E extract) as compared to control treatment.

Table 5. 2,2-diphenyl-1-picrylhydrazyl (DPPH) and total phenolic content (TPC) of chicken meat treated with gamma irradiation and turmeric powder at different storage periods (0, 7th, and 14th days)

		Storage period (days)
		0			7			14
Parameter	Treatments	Aerobic	Vacuum	Means	Aerobic	Vacuum	Means	Aerobic	Vacuum	Means
DPPH (%)	0 kGy	66.00 ± 2.64	70.00 ± 2.27	68.00 ± 1.00de	63.00 ± 1.83	67.00 ± 2.44	65.00 ± 1.02fg	59.00 ± 1.71	63.00 ± 1.83	60.99 ± 0.40ijk
	1 kGy	62.00 ± 2.80	67.00 ± 2.44	64.49 ± 1.02fgh	59.00 ± 2.49	65.00 ± 2.11	61.99 ± 1.50hi	57.00 ± 2.41	61.00 ± 2.56	59.00 ± 0.80jk
	2 kGy	59.00 ± 2.49	64.00 ± 1.79	61.49 ± 1.20ij	55.00 ± 1.89	62.00 ± 2.80	58.50 ± 1.16k	51.00 ± 1.16	57.00 ± 2.17	54.00 ± 1.6l
	0 kGy +TP	76.00 ± 2.51	81.00 ± 1.58	78.50 ± 1.00a	74.00 ± 2.41	79.00 ± 2.89	76.49 ± 1.30a	68.00 ± 2.67	76.00 ± 2.40	71.99 ± 1.20bc
	1 kGy + TP	72.00 ± 2.08	75.00 ± 2.85	73.50 ± 0.50b	69.00 ± 3.20	74.00 ± 2.41	71.50 ± 1.70bc	66.00 ± 2.64	71.00 ± 2.39	68.49 ± 1.90de
	2 kGy + TP	68.00 ± 2.82	72.00 ± 2.08	69.99 ± 1.50cd	64.00 ± 1.79	68.00 ± 2.82	65.99 ± 0.80ef	61.00 ± 2.56	64.00 ± 2.26	62.55 ± 1.70ghi
	Means	67.16 ± 1.50c	71.50 ± 1.13a		64.00 ± 1.17d	69.16 ± 1.02b		60.34 ± 0.90e	65.33 ± 1.40d
TPC (mg/g GAE)	0 kGy	97.00 ± 2.66	104.00 ± 2.43	100.50 ± 0.5gh	95.00 ± 2.94	103.00 ± 2.95	99.00 ± 0.8gh	92.00 ± 5.00	99.00 ± 2.66	95.50 ± 1.15i
	1 kGy	88.00 ± 3.38	95.00 ± 3.11	91.50 ± 2.0j	84.00 ± 2.17	91.00 ± 4.01	87.50 ± 1.9kl	79.00 ± 3.58	88.00 ± 3.38	83.50 ± 2.06m
	2 kGy	84.00 ± 2.17	92.00 ± 5.00	88.00 ± 0.9k	81.00 ± 3.40	88.00 ± 3.38	84.50 ± 1.1lm	74.00 ± 2.41	83.00 ± 1.26	78.50 ± 1.70n
	0 kGy + TP	118.00 ± 2.11	126.00 ± 2.59	122.00 ± 1.2a	113.00 ± 1.28	122.00 ± 2.66	117.50 ± 1.0b	109.00 ± 2.71	119.00 ± 2.36	114.00 ± 1.60c
	1 kGy + TP	106.00 ± 2.41	113.00 ± 1.28	109.50 ± 1.60d	102.00 ± 3.05	110.00 ± 3.21	106.00 ± 1.80e	97.00 ± 2.66	107.00 ± 2.69	102.00 ± 1.21fg
	2 kGy + TP	102.00 ± 3.35	107.00 ± 2.69	104.50 ± 1.70ef	99.00 ± 2.66	104.00 ± 2.43	101.50 ± 1.16fgh	96.00 ± 1.96	101.00 ± 2.73	98.50 ± 1.54hi
	Means	99.17 ± 1.20c	106.17 ± 1.16a		95.66 ± 1.18d	103.00 ± 0.70b		91.17 ± 1.14e	99.50 ± 1.50c

TP, turmeric powder

The values are mean ±SD of three independent determinations

Means carrying different letters in rows or columns differed significantly

TPCs

The results regarding the TPC of chicken meat samples have significant effects with respect to treatments, packaging, and storage interval. Higher TPC (126.00 ± 2.59 mg/g GAE) was observed in treated (0 kGy + TP) vacuum-packaged samples on day 0 of storage, followed by aerobic-packaged treated (0 kGy + TP) chicken meat samples (118.00 ± 2.11 mg/g GAE) on day 0, whereas minimum value (74.00 ± 2.41 mg/g GAE) was observed in the aerobic-packaged samples treated with a dose of 2 kGy on the 14th day of storage (Table 5). The results proved that the TPC significantly increased in vacuum-packaged chicken meat samples as compared to aerobic samples. Also, with the passage of time, the TPC in untreated chicken samples (control) declined. TPC found in treated and untreated chicken meat samples also increased with the addition of TP in both aerobic- and vacuum-packaged samples. The result showed that the treated sample of chicken meat had higher TPC in untreated (control) samples, whereas a lower value was found in aerobic packaging, which is in agreement with the results of;^[59] they reported that the total phenolic content decreased significantly at each interval of storage period in vacuum-packaged fresh chicken sausages. However, treated products showed a slower rate of decrease, indicating that these possess better oxidative stability than the control. Our results agreed with other studies demonstrating that the meat from goat fed with Moringaoleifera leaves had a higher concentration of total phenolic content (mainly tannin content) than the meat of goat fed a control diet.^[60] Another study stated that the highest level of TPC was found in S. aromaticum, while C. cassia showed the lowest level in raw chicken meat.^[61] It is considered that during the storage period, the phenolic content decreased significantly in all fresh chicken sausage products at each interval of storage period.^[59]

TVBN assay

The results regarding the TVBN value of chicken meat samples have significant effects with respect to treatments, packaging, and storage interval. Higher value of TVBN (5.26 ± 0.39 mg/100 mL) was observed in untreated (0 kGy) aerobic-packaged control samples on day 14 of storage, followed by vacuum-packaged untreated (0kGy) chicken meat samples (5.11 ± 0.35 mg/100 mL) on day 14, whereas the results showed that the minimum value (2.98 ± 0.20 mg/100 mL) was observed in the vacuum-packaged samples treated with 0 kGy + TP on day 0 of storage, as listed in Table 6. The results depicted that the TVBN value significantly decreased in vacuum-packaged chicken meat samples as compared to aerobic samples. Moreover, the TVBN value in untreated chicken samples (control) increased with the passage of time, while irradiation with and without TP suppressed the increase of TVBN value with storage intervals. The TVBN value in treated and untreated chicken meat samples also decreased with the addition of TP in both aerobic- and vacuum-packaged samples. The results indicated that the treated samples of chicken meat have a lower value in vacuum packaging, while a higher value of TVBN was found in treated samples, which are in consistent with the results of,^[62] who confirmed that in irradiated camel meat, volatile basic nitrogen (VBN) tends to diminish after its storage for about 2 weeks. By reducing the initial level of common spoilage bacteria, increasing the applied dose can reduce the rate of VBN formation during storage. Another study depicted that TVBN increased at the storage period increased which is in line with the findings of the current study. This indicates that an increase in TVBN was suppressed by a dose of 0.5 kGy, with a significant difference observed between the irradiated and non-irradiated samples.^{[47] [33]} demonstrated that TVBN content significantly increased with the storage interval but radiation treatment supresses the formation of TVBN during storage period. Another study depicted that, TVBN increased at day 0 without the radiation treatment but due to irradiated samples, the TVBN value decreased during storage interval of day 40 as compared to non-irradiated samples.^[30]

Table 6. Total volatile basic nitrogen (TVBN) of chicken meat treated with gamma irradiation and turmeric powder at different storage periods (0, 7th, and 14th days)

		Storage period (days)
		0			7			14
Parameter	Treatments	Aerobic	Vacuum	Means	Aerobic	Vacuum	Means	Aerobic	Vacuum	Means
TVBN (mg/100 mL)	0 kGy	3.45 ± 0.21	3.39 ± 0.23	3.42 ± 1.30ij	4.76 ± 0.33	4.23 ± 0.25	4.49 ± 0.50c	5.26 ± 0.39	5.11 ± 0.35	5.18 ± 1.60a
	1 kGy	4.13 ± 0.30	4.07 ± 0.27	4.10 ± 1.21def	3.66 ± 0.25	3.45 ± 0.21	3.55 ± 1.80hi	4.06 ± 0.27	3.74 ± 0.25	3.89 ± 2.10fg
	2 kGy	4.96 ± 0.33	4.72 ± 0.30	4.84 ± 1.40b	4.12 ± 0.31	3.97 ± 0.24	4.04 ± 1.30ef	4.45 ± 0.24	4.32 ± 0.29	4.38 ± 1.30cd
	0 kGy +TP	3.14 ± 0.21	2.98 ± 0.20	3.06 ± 1.00k	4.23 ± 0.25	3.45 ± 0.21	3.84 ± 2.00fgh	4.87 ± 0.32	4.02 ± 0.24	4.44 ± 1.80c
	1 kGy + TP	3.93 ± 0.25	3.71 ± 0.25	3.82 ± 0.80fgh	3.23 ± 0.16	3.07 ± 0.22	3.15 ± 1.90jk	3.74 ± 0.25	3.69 ± 0.22	3.71 ± 1.07ghi
	2 kGy + TP	4.39 ± 0.31	4.08 ± 0.27	4.23 ± 1.10cde	3.84 ± 0.20	3.34 ± 0.23	3.59 ± 1.10hi	4.21 ± 0.25	3.95 ± 0.27	4.07 ± 1.01ef
	Means	3.99 ± 1.06bc	3.82 ± 1.70c		3.97 ± 1.62bc	3.58 ± 1.43d		4.43 ± 0.74a	4.13 ± 0.88b

TP, turmeric powder

The values are mean ±SD of three independent determinations

Means carrying different letters in rows or columns differed significantly

Sensory evaluation

The mean scores for appearance, texture, taste, odour of the sensory evaluation, and the overall gamma irradiation tolerability of the meat of chicken treated with turmeric powder were determined. The sensory attributes decreased with the increase in gamma irradiation dose. They also decreased in aerobic packaging as the storage period increased, whereas sensory attributes increased in vacuum packaging as compared to aerobic packaging. The sensory score for appearance ranged from 7.4 ± 0.23 to 6.8 ± 0.25 and 7.8 ± 0.08 to 7.4 ± 0.22, texture 7.6 ± 0.31 to 6.6 ± 0.25 and 7.6 ± 0.08 to 6.8 ± 0.09, taste 7.4 ± 0.28 to 6.4 ± 0.24 and 7.6 ± 0.06 to 6.6 ± 0.41, odour 7.6 ± 0.01 to 6 ± 0.8 and 7.8 ± 0.2 to 6.2 ± 0.24, and overall acceptability 7.45 ± 0.32 to 6.45 ± 0.4 and 7.65 ± 0.08 to 6.65 ± 0.14 in aerobic and vacuum packaging, respectively, on day 0 of storage (Table 7). As the storage intervals increased, the sensory scores designed for the different sensory attributes decreased considerably. This was all a consequence of reduction in the sensory score during storage due to the increase in lipid oxidation levels caused by the irradiation, which results in lower acceptability, but on the whole the acceptability was within the acceptable range. The outcomes of the present study correlate with^[63] and,^[64] who reported that with storage period, the taste of nuggets significantly decreased. There was a significant decrease in all the sensory scores with the advancement in the duration of storage. Furthermore, the acquired results are in agreement with those of,^[65] who found that the taste, texture, colour, and odour of camel meat reduced in vacuum packaging. The changes in the odour and colour of the irradiated meat are highly dependent on the packaging conditions. Another study stated the decrease in the sensory score during storage for e-beam-irradiated and vacuum-packaged grass carp surimi.^[66] Our results are in agreement with those of,^[1] who reported that in poultry meat treated with irradiation, on the 28th day of storage, the sensory score decreased gradually. ^[67] observed that turmeric showed significant effects on the control of fat oxidative rancidity of cara beef pastirma.

Table 7. Sensory evaluation (appearance, texture, taste, odour, and overall acceptability) of chicken meat treated with gamma irradiation and turmeric powder at different storage periods (0, 7th, and 14th days)

		Storage period (days)
		0			7			14
Parameter	Treatments	Aerobic	Vacuum	Means	Aerobic	Vacuum	Means	Aerobic	Vacuum	Means
Appearance	0 kGy	7.4 ± 0.23	7.8 ± 0.08	7.6 ± 0.02	7.2 ± 0.21	7.4 ± 0.25	7.3 ± 0.23	6.6 ± 0.36	7.2 ± 0.14	6.9 ± 0.42
	1 kGy	7.4 ± 0.25	7.8 ± 0.07	7.6 ± 0.05	7 ± 0.25	7.2 ± 0.31	7.1 ± 0.25	6.4 ± 0.07	6.8 ± 0.47	6.6 ± 0.45
	2 kGy	7.6 ± 0.09	7.6 ± 0.28	7.6 ± 0.08	6.8 ± 0.64	7.2 ± 0.28	7 ± 0.28	6.4 ± 0.09	6.8 ± 0.25	6.6 ± 0.48
	0 kGy +TP	7.2 ± 0.08	7.4 ± 0.67	7.3 ± 0.09	6.8 ± 0.41	7 ± 0.22	6.9 ± 0.31	6.2 ± 0.26	6.6 ± 0.15	6.4 ± 0.52
	1 kGy + TP	7.4 ± 0.21	7.6 ± 0.17	7.5 ± 0.12	6.6 ± 0.42	7 ± 0.16	6.8 ± 0.34	6.2 ± 0.27	6.6 ± 0.03	6.4 ± 0.55
	2 kGy + TP	6.8 ± 0.25	7.4 ± 0.22	7.1 ± 0.15	6.6 ± 0.24	6.8 ± 0.27	6.7 ± 0.37	6.2 ± 0.06	6.4 ± 0.02	6.3 ± 0.59
	Means	7.3 ± 0.01	7.6 ± 0.10		6.83 ± 0.18	7.1 ± 0.20		6.3 ± 0.39	6.73 ± 0.41
Texture	0 kGy	7.4 ± 0.13	7.2 ± 0.32	7.3 ± 0.62	7 ± 0.21	7.2 ± 0.06	7.1 ± 0.03	6.4 ± 0.01	6.8 ± 0.07	6.6 ± 0.14
	1 kGy	7.2 ± 0.12	7.2 ± 0.51	7.2 ± 0.65	6.8 ± 0.12	6.8 ± 0.38	6.8 ± 0.07	6.4 ± 0.42	6.6 ± 0.04	6.5 ± 0.35
	2 kGy	7.2 ± 0.19	7.2 ± 0.16	7.2 ± 0.68	6.6 ± 0.35	6.8 ± 0.01	6.7 ± 0.10	6.2 ± 0.06	6.6 ± 0.1	6.4 ± 0.20
	0 kGy + TP	7.6 ± 0.31	7.6 ± 0.08	7.6 ± 0.61	6.6 ± 0.41	6.6 ± 0.09	6.6 ± 0.06	6.2 ± 0.3	6.3 ± 0.01	6.25 ± 0.22
	1 kGy + TP	7.3 ± 0.26	7.5 ± 0.38	7.4 ± 0.63	6.4 ± 0.06	6.6 ± 0.010	6.5 ± 0.11	6.2 ± 0.19	6.4 ± 0.0	6.3 ± 0.24
	2 kGy + TP	6.6 ± 0.25	6.8 ± 0.09	6.7 ± 0.11	6.4 ± 0.01	6.4 ± 0.04	6.4 ± 0.17	6.2 ± 0.35	6.4 ± 0.21	6.3 ± 0.31
	Means	7.22 ± 0.29	7.25 ± 0.16		6.63 ± 0.19	6.73 ± 0.18		6.27 ± 0.22	6.52 ± 0.28
Taste	0 kGy	7.4 ± 0.28	7.6 ± 0.06	7.5 ± 0.10	7 ± 0.03	7.2 ± 0.21	7.1 ± 0.60	6.2 ± 0.27	6.6 ± 0.04	6.4 ± 0.84
	1 kGy	7.4 ± 0.39	7.6 ± 0.39	7.5 ± 0.15	6.8 ± 0.14	6.8 ± 0.38	6.8 ± 0.65	6 ± 0.26	6.2 ± 0.08	6.1 ± 0.86
	2 kGy	7.4 ± 0.31	7.6 ± 0.38	7.5 ± 0.25	6.8 ± 0.12	6.8 ± 0.32	6.8 ± 0.62	5.8 ± 0.12	6.2 ± 0.06	6 ± 0.89
	0 kGy + TP	6.6 ± 0.47	7 ± 0.36	6.8 ± 0.30	6.2 ± 0.15	6.6 ± 0.42	6.4 ± 0.75	5.8 ± 0.49	6 ± 0.1	5.9 ± 0.92
	1 kGy + TP	6.4 ± 0.22	6.6 ± 0.44	6.5 ± 0.35	6.2 ± 0.18	6.4 ± 0.14	6.3 ± 0.04	5.6 ± 0.35	5.8 ± 0.2	5.7 ± 0.95
	2 kGy + TP	6.4 ± 0.24	6.6 ± 0.41	6.5 ± 0.40	6 ± 0.41	6.4 ± 0.12	6.2 ± 0.08	5.6 ± 0.08	6 ± 0.07	5.8 ± 0.98
	Means	6.93 ± 0.35	7.17 ± 0.48		6.5 ± 0.52	6.7 ± 0.58		5.83 ± 0.80	6.13 ± 0.14
Odor	0 kGy	7.6 ± 0.01	7.8 ± 0.2	7.7 ± 0.15	6.8 ± 0.22	7 ± 0.01	6.9 ± 0.21	6 ± 0.28	6.4 ± 0.21	6.2 ± 0.25
	1 kGy	7.6 ± 0.02	7.8 ± 0.7	7.7 ± 0.09	6.8 ± 0.32	6.8 ± 0.05	6.8 ± 0.33	5.8 ± 0.36	6.2 ± 0.28	6 ± 0.30
	2 kGy	7 ± 0.2	7.4 ± 0.01	7.2 ± 0.04	6.6 ± 0.02	6.6 ± 0.6	6.6 ± 0.45	5.8 ± 0.34	6.2 ± 0.19	6 ± 0.52
	0 kGy +TP	6.4 ± 0.04	6.8 ± 0.5	6.6 ± 0.07	6.2 ± 0.01	6.4 ± 0.35	6.3 ± 0.58	5.6 ± 0.31	5.8 ± 0.12	5.7 ± 0.44
	1 kGy + TP	6.2 ± 0.06	6.4 ± 0.6	6.3 ± 0.08	5.6 ± 0.01	6.2 ± 0.32	5.9 ± 0.67	5.4 ± 0.39	5.6 ± 0.14	5.5 ± 0.29
	2 kGy + TP	6 ± 0.8	6.2 ± 0.24	6.1 ± 0.35	5.6 ± 0.05	6.2 ± 0.21	5.9 ± 0.72	5.4 ± 0.25	5.6 ± 0.17	5.5 ± 0.64
	Means	6.8 ± 0.07	7.07 ± 0.28		6.27 ± 0.35	6.53 ± 0.39		5.67 ± 0.45	5.97 ± 0.58
Overall Acceptability	0 kGy	7.45 ± 0.32	7.65 ± 0.08	7.55 ± 0.25	7 ± 0.07	7.2 ± 0.10	7.1 ± 0.05	6.3 ± 0.30	6.75 ± 0.28	6.53 ± 0.22
	1 kGy	7.4 ± 0.15	7.65 ± 0.60	7.53 ± 0.12	6.85 ± 0.09	6.9 ± 0.02	6.88 ± 0.23	6.15 ± 0.02	6.4 ± 0.24	6.28 ± 0.36
	2 kGy	7.4 ± 0.06	7.5 ± 0.40	7.45 ± 0.09	6.7 ± 0.80	6.85 ± 0.3	6.78 ± 0.33	6.05 ± 0.5	6.4 ± 0.26	6.23 ± 0.59
	0 kGy + TP	6.95 ± 0.70	7.1 ± 0.04	7.03 ± 0.03	6.45 ± 0.10	6.65 ± 0.5	6.55 ± 0.13	5.95 ± 0.14	6.15 ± 0.14	6.05 ± 0.73
	1 kGy + TP	6.85 ± 0.06	6.85 ± 0.01	6.85 ± 0.10	6.2 ± 0.40	6.55 ± 0.04	6.38 ± 0.11	5.85 ± 0.06	6.05 ± 0.03	5.95 ± 0.96
	2 kGy + TP	6.45 ± 0.40	6.65 ± 0.14	6.55 ± 0.18	6.15 ± 0.06	6.45 ± 0.08	6.3 ± 0.01	5.85 ± 0.07	5.95 ± 0.04	5.9 ± 0.46
	Means	7.08 ± 0.21	7.23 ± 0.11		6.56 ± 0.16	6.77 ± 0.46		6.03 ± 0.68	6.28 ± 0.97

TP, turmeric powder

The values are mean ± SD of 10 independent determinations

Conclusion

This study points out that using different doses of gamma irradiation significantly improved the quality of chicken meat with some insignificant changes in physicochemical properties during storage. The population of TAB in the chicken meat was decontaminated by using a dose of 2 kGy + TP in both aerobic and vacuum packaging on the 0, 7^th, and 14th days of storage, whereas complete decontamination of coliforms was achieved by different doses of gamma irradiation during storage, in both aerobic and vacuum packaging. A decreasing trend of the antioxidant profile was observed during storage, but it was higher in vacuum packaging compared to aerobic packaging. Similarly, the TVBN value was suppressed in vacuum packaging compared to aerobic packaging by using different doses of gamma irradiation all through the storage period. Negligible effect with respect to the irradiation dose was observed in the diverse sensory parameters, but during storage, a decreasing trend was observed. There is a synergistic effect caused by the low dose of gamma irradiation and vacuum packaging on the quality and shelf life of chicken meat.

Acknowledgments

The authors are highly thankful to Government College University Faisalabad, Pakistan, and Nuclear Institute for Food and Agriculture, Peshawar, Pakistan, for providing financial support for this study.

Additional information

Funding

The authors also extend their appreciation to the International Scientific Partnership Program (ISPP) at King Saud University for funding this research work through ISPP# 0023.