Journal of Animal Science and Technology
Korean Society of Animal Sciences and Technology
RESEARCH ARTICLE

Optimization of dry-aging conditions for chicken meat using the electric field supercooling system

Chang-Hwan Jeong1https://orcid.org/0000-0003-2803-2461, Sol-Hee Lee1,*https://orcid.org/0000-0003-1124-7095, Hack-Youn Kim1,*https://orcid.org/0000-0001-5303-4595
1Department of Animal Resources Science, Kongju National University, Yesan 32439, Korea
*Corresponding author: Sol-Hee Lee, Department of Animal Resources Science, Kongju National University, Yesan 32439, Korea., Tel: +82-41-330-1041, E-mail: chzh73@naver.com
*Corresponding author: Hack-Youn Kim, Department of Animal Resources Science, Kongju National University, Yesan 32439, Korea., Tel: +82-41-330-1041, E-mail: kimhy@kongju.ac.kr

© Copyright 2024 Korean Society of Animal Science and Technology. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received: Jun 12, 2023; Revised: Jul 06, 2023; Accepted: Jul 09, 2023

Published Online: May 31, 2024

Abstract

This study was designed to determine the optimal aging conditions after analyzing the physicochemical and microbiological properties of dry-aged chicken breast using an electric field supercooling system (EFSS). Chicken breast was aged for up 5 weeks at three different temperatures (0°C, −1°C, and −2°C). Aging and trimming loss at −2°C treatment showed lower values than at 0°C and −1°C treatments. Thiobarbituric acid reactive substances and volatile basic nitrogen in all treatments increased during the aging process but showed the lowest levels at −2°C. As a result of analysis of aerobic bacteria, it is microbiologically safe to dry-age for up to 2 weeks at 0°C and up to 3 weeks at −1°C and −2°C. Therefore, the dry-aged chicken breast with EFSS was optimally aged for 3 weeks at −2°C.

Keywords: Aging condition; Chicken breast; Dry aging; Electric field refrigerator; Supercooling system

INTRODUCTION

Poultry consumption is increasing worldwide owing to its high nutritional value and low price [1]. In addition, chickens have more histidyl dipeptides (carnosine and anserine) than pork and beef but have a short shelf life due to rapid microbial growth [2]. Petrou et al. [3] reported that the short shelf life of chicken leads to low consumption; therefore, inventory can accumulate, and studies are being conducted to apply aging, salting, and fermentation to chicken.

Dry aging involves aging in a ventilated refrigeration facility by adjusting the drying temperature, relative humidity, aging days, and air flow in a state where the surface of the meat can come into contact with the outside world [4]. During the dry-aging process, myofibrillar proteins in meat are decomposed into small peptides and free amino acids by cathepsin and calpain, resulting in increased tenderness and a unique flavor [5]. However, it is necessary to compensate for these disadvantages because of microbial contamination and excessive weight loss due to the removal of the hardened surface [6].

An electric field supercooling system (EFSS) is a technology that applies a certain amount of electric field to vibrate water molecules so that ice crystals are not formed at temperatures below the freezing point [7]. In general, dry aging is performed at a temperature range of 0°C–4°C; however, when using an EFSS, aging is possible in the range of −3°C–(−1°C) [8]. Low-temperature aging using an EFSS can reduce weight loss by lowering moisture loss and can improve the shelf life of food by preventing meat spoilage and the proliferation of pathogenic microorganisms [9].

Therefore, this study applied an EFSS to chicken breast and dry-aged it at three temperatures, then the physicochemical and microbiological properties were compared and analyzed to determine the optimal aging temperature and period.

MATERIALS AND METHODS

Sample preparation

The breast meat of 32 d-old broiler (Gallus gallus domesticus) with completed postmortem rigor was used. Meats weighing approximately 120–140 g were used as samples after classification. The samples were classified into three treatments based on the aging temperature (0°C, −1°C, and −2°C). The aging temperatures was designed to be suitable for poultry meat refrigeration conditions in Korea after confirming that aging was possible at a temperature below 0°C when using the electric field supercooling refrigerator (ARD-090RM-F, Mars, Fukushima, Japan) in a previous study [10]. Each sample was dry-aged using an electric field supercooling refrigerator (Fig. 1) and was placed so that the air was in uniform contact. The pulsed electric field module was applied to the electric field refrigerator, and a magnetic field was created by applying a voltage. The refrigerator conditions were as follows: air velocity, 5 ± 2 m/s; electric field strength, 0.58 kV/cm; voltage 7 kV; frequency 60 Hz, electric current 5 mA, pulse width 20 μs.

jast-66-3-603-g1
Fig. 1. Electric field supercooling refrigerator (outside / inside).
Download Original Figure

The samples were collected at intervals of 1 week, and the hardened surfaces of the samples were trimmed. The hardened surface was used to measure the thiobarbituric acid reactive substance (TBARS), volatile basic nitrogen (VBN), aerobic bacteria count (AC), and for other experiments, the surface-romoved edible part was used. Dry aging was terminated when there were no usable edible parts, and dry aging was performed for the 4 weeks in the 0°C treatments and the 5 weeks in the −1°C and −2°C treatments.

Aging loss

Aging loss was determined based on the weight before and after aging. The equation for the aging yield calculation is as follows:

Aging loss ( % ) = 100 Sample weight after aging ( g ) Sample weight before aging ( g ) × 100
Trimming loss

Trimming loss was determined based on the weight before and after trimming. The equation for the trimming yield calculation is as follows:

Trimming loss ( % ) = 100 Sample weight after trimming ( g ) Sample weight after aging ( g ) × 100
pH

For the measurement of pH, the chicken breast were finely ground under sterile conditions. Then, it was homogenized (6,451×g, 1 min) with deionized water (DIW) at a ratio of 1:4 using an Ultra turrax (HMZ-20DN, Poonglim Tech, Seongnam, Korea). The pH of homogenate was determined using a pH meter, and it was calibrated with the standard buffer solutions.

Water-holding capacity

The water-holding capacity (WHC) was determined by partially modifying the compression method described by [11]. The core of chicken breast 3 mg was placed on filter paper and pressed for 3 min using a filter press device. The areas of the inner and outer ring zones on the filter paper were measured using a planimeter. The equation for the WHC calculation is as follows:

WHC ( % ) = Inner ring zone ( mm 2 ) Outer ring zone ( mm 2 ) × 100
Color

The chicken breast was divided into halves and the center was measured using a colorimeter (CR-10, Minolta, Tokyo, Japan). The colorimeter uses a D65 light source with an illuminated area of 8 mm. The measured lightness, redness, and yellowness are expressed as CIE L*, CIE a*, and CIE b*, respectively.

Thiobarbituric acid reactive substance

TBAR was determined using the distillation method described by [12]. Ten grams of chicken breast and 50 mL of DIW were homogenized for 1 min (5,614×g) using a homogenizer (AM-5, Nihonseiki Kaisha), and 200 μL of 0.3% butylated hydroxytoluene was added to prevent further oxidation. After adding 2.5 mL of 4N HCl and 47.5 mL of DIW were added to the homogenate, which was boiled using a heating machine (MS-E102, Lab Merchant, London, UK). The resulting distillate and 0.02 M 2-thiobarbituric acid in 90% acetate were mixed in a ratio of 1:1. The mixture was heated at 100°C for 35 min and cooled in cool water for 20 min. The absorbance of the mixture was measured at 538 nm using a spectrophotometer (Spectra Max ID3, Molecular Devices, San Jose, CA, USA). The data were substituted into the standard curve to calculate the amount of malondialdehyde (MDA), and 1,1,3,3-tetraethoxypropane was used as the standard. TBARS was expressed as mg MDA/kg chicken breast.

Volatile basic nitrogen

The volatile basic nitrogen (VBN) content was determined by partially modifying the Conway microdiffusion method [13]. Ten grams of chicken breast and 90 mL of DIW were homogenized for 2 min (5,614×g) using a homogenizer (AM-5, Nihonseiki Kaisha, Tokyo, Japan). The homogenate was used as a sample after filtering through filter paper. The Conway reagent 100 μL and 1 mL of 0.01N H3BO3 were aliquoted into the inner Conway dish. In the outer part of the Conway dish, 1 mL of the filtrate and 1 mL of 50% K2CO3 were aliquoted. For the blank sample, 1 mL of DIW was used and 50% K2CO3 was not added. Vaseline was applied to the lid of a Conway dish to prevent oxygen permeation. Conway dishes were incubated for 2 h at 37°C. 0.02N H2SO4 was aliquoted until the solution in the inner part of the Conway dish changed from green to red. The equation for the VBN calculation is as follows:

VBN ( mg% ) = A 1 ( μ L ) A 2 ( μ L ) W ( g ) × 0.14 × t × d

where A1 and A2 are aliquots of the sample solution and blank, respectively; W is the weight of the sample; t is the titer value of 0.02 N H2SO4; and d is the dilution factor.

Aerobic bacteria

Chicken breast tissue (25 g) and buffer peptone water (225 mL) were homogenized for 1 min using a stomacher. Dilution solutions were prepared by mixing 1 mL of homogenate with 9 mL of BPW, and the process was repeated as needed. Zero point one mL of the diluted solution was spread onto tryptic soy agar, then smeared, and incubated at 37°C for 24 h. The number of colonies cultured was measured and expressed as log CFU/g.

Statistical analysis

All data were composed by treatments and aging periods, and presented as the mean values ± standard deviations carried out a statistical analysis. The physicochemical and microbial properties of the chicken breast were analyzed by one-way analysis of variance using the GLM procedure with the SAS program. Statistically significant differences were determined at 5% level using Duncan’s multiple range test.

RESULTS AND DISCUSSION

Aging loss and trimming loss

Table 1 shows the aging loss and trimming loss based on the aging temperature and aging period of dry-aged chicken breast subjected to an EFSS. The aging loss and trimming loss by temperature of dry-aged chicken breast subjected to the EFSS tended to increase as the aging period increased. In dry aging, non-edible parts are created because the surface of the meat comes into contact with air and moisture evaporates [14]. The aging loss of the −2°C treatment showed a significantly lower value than that of the 0°C and −1°C treatments in all aging periods (p < 0.05). Trimming loss showed a significantly lower value in the −2°C treatment than in the 0°C and −1°C treatments in the 3rd and 5th weeks (p < 0.05). It is known that the lower the aging temperature of meat, the slower the muscle contraction rate and the faster the moisture in the meat is discharged to the outside [15]. Therefore, it is suggested that the aging loss and trimming loss are low as moisture is discharged the slowest in the −2°C treatment where the aging temperature is the lowest.

Table 1. Aging loss (%) and trimming loss (%) based on the aging temperatures and aging periods of dry-aged chicken breast subjected to the electric field supercooling system
Traits Temperature (°C) Dry-aging period (weeks)
1 2 3 4 5
Aging loss 0 25.08 ± 3.71Ac 44.93 ± 2.36Ab 56.01 ± 1.49Aa 57.00 ± 2.43Aa NA
−1 24.09 ± 2.09Ac 38.27 ± 1.46Bb 53.84 ± 3.59Aa 57.47 ± 4.96Aa 67.06 ± 2.68Aa
−2 12.98 ± 2.09Bc 27.27 ± 2.89Cb 36.42 ± 4.24Ba 47.18 ± 3.76Ba 50.64 ± 3.93Ba
Trimming loss 0 35.18 ± 5.68Ac 43.93 ± 4.20Ab 65.94 ± 4.00Aab 67.04 ± 8.35Aa NA
−1 30.69 ± 5.03Ac 44.49 ± 1.14Ab 69.35 ± 3.47Aa 69.20 ± 2.64Aa 72.85 ± 1.97Aa
−2 33.57 ± 4.68Ac 43.66 ± 1.39Ab 62.33 ± 4.73Ba 66.15 ± 3.24Aa 66.16 ± 4.02Ba

All values are mean ± SD.

Means in the same row with different numbers are significantly different (p < 0.05).

Means in the same column with different numbers are significantly different (p < 0.05).

NA, Not applicable.

Download Excel Table
pH

Table 2 shows the pH based on the aging temperature and aging period of the dry-aged chicken breast subjected to EFSS. During the aging process of meat, endogenous proteases such as cathepsin and calpains degrade proteins, and pH increases as metabolites are produced [16]. Therefore, it seems that the pH of dry-aged chicken breast tends to increase as the aging period increases. When electric field stimulation is applied to intramuscular organelles, membrane permeability increases, and when calcium ion inflow from the outside of the cell and intracellular calcium ion concentration increase, proteolytic enzymes that release calcium ions from the cell membrane are secreted [17]. Representative proteolytic enzymes include cathepsin B and cathepsin L, secreted from lysosomes. The pH increased because the number of metabolites was increased by these proteolytic enzymes. The pH of the −2°C treatment showed a significantly lower value than the 0°C and −1°C treatments in the 1st week (p < 0.05); however, there was no significant difference in the subsequent aging period. In meat, the lower the aging temperature, the lower the activity of the proteolytic enzymes cathepsin B and H [18]. Therefore, since the activity of proteolytic enzymes was lower in the −2°C treatment with a lower aging temperature than in the 0°C and −1°C treatments, the amount of metabolites produced was small and the pH was low. However, the pH level of chicken breast meat did not show any difference after the 2nd week because the endogenous protease showed a difference in activity depending on the temperature; however, it was exhausted before the 2nd week of aging.

Table 2. pH based on the aging temperatures and aging period of dry-aged chicken breast subjected to the electric field supercooling system
Trait Temperature (°C) Dry-aging period (weeks)
0 1 2 3 4 5
pH 0 5.87 ± 0.02b 5.96 ± 0.02Aab 6.01 ± 0.17ab 6.07 ± 0.02a 6.10 ± 0.17a NA
−1 5.87 ± 0.02d 5.96 ± 0.03Ac 6.04 ± 0.04b 6.06 ± 0.04b 6.20 ± 0.09a 6.28 ± 0.07a
−2 5.87 ± 0.02d 5.85 ± 0.03Bd 5.93 ± 0.03cd 6.02 ± 0.04bc 6.07 ± 0.14b 6.30 ± 0.06a

All values are mean ± SD.

Means in the same row with different numbers are significantly different (p < 0.05).

Means in the same column with different numbers are significantly different (p < 0.05).

NA, Not applicable.

Download Excel Table
Water-holding capacity

Table 3 shows the WHC based on the aging temperature and aging period of dry-aged chicken breast subjected to the EFSS. The WHC of dry-aged chicken breasts subjected to EFSS showed a tendency to increase as the aging period increased at all temperatures, and the 0°C and −1°C treatments significantly increased until the 3rd and 4th weeks, respectively (p < 0.05). As the pH of meat deviates from its isoelectric point (approximately 5.0–5.4), the water retention capacity increases as the space between protein molecules that can contain water widens [19]. Accordingly, as the pH increases during the dry-aging process, the WHC may be enhanced. After the 2nd week of dry aging, the WHC of the −2°C treatment was significantly lower than that of the 0°C and −1°C treatments (p < 0.05). The drying speed of the −2°C treatment was slow owing to the relatively low aging temperature, but the 0°C and −1°C treatments were fast-drying to the core, indicating a large increase in WHC. In the 0°C and −1°C treatments, the WHC was not measured at the 4th and 5th weeks, respectively. This is the result of the absence of moisture that can be measured by the compression method, as both free water evaporates from chicken breast due to dry aging, and this meat is suggested to be at an unsuitable level for consumption. Therefore, when dry aging chicken breast by applying the EFSS, it is considered appropriate to age the 0°C, −1°C, and −2°C treatments until weeks 3rd, 4th, and 5th weeks, respectively, when the WHC can be measured.

Table 3. Water holding capacity (WHC, %) based on the aging temperatures and aging period of dry-aged chicken breast subjected to the electric field supercooling system
Trait Temperature (°C) Dry-aging period (weeks)
0 1 2 3 4 5
WHC 0 54.02 ± 2.34c 65.10 ± 4.58b 93.42 ± 2.52Aa 98.14 ± 0.78Aa NA NA
−1 54.02 ± 2.34e 62.19 ± 4.10d 75.50 ± 4.98Bc 89.26 ± 2.34Bb 96.71 ± 2.94Aa NA
−2 54.02 ± 2.34e 60.02 ± 4.10de 64.32 ± 4.60Cbc 67.00 ± 4.31Cbc 69.48 ± 7.10Bab 76.00 ± 9.35a

All values are mean ± SD.

Means in the same row with different numbers are significantly different (p < 0.05).

Means in the same column with different numbers are significantly different (p < 0.05).

NA, Not applicable.

Download Excel Table
Color

Table 4 shows the color based on the aging temperatures and aging periods of the dry-aged chicken breast subjected to the EFSS. Zhang et al. [20] reported that the lightness value of meat decreases as the amount of scattered light decreases as moisture evaporates during the dry-aging process. Accordingly, the lightness of all treatments tended to decrease as the aging period elapsed. In addition, the −2°C treatment showed a relatively higher lightness value than the 0°C and −1°C treatments, which was due to the relatively low loss of moisture during the drying process because the −2°C treatment had a lower aging temperature. The redness and yellowness of all the treatments tended to increase as the aging period increased. Also, in the 3rd and 4th weeks, the 0°C treatment showed significantly higher redness and yellowness than the −1°C and −2°C treatments (p < 0.05). These results suggest that the protein content in meat increases as the water content decreases significantly, and the myoglobin content increases accordingly [21].

Table 4. Color based on the aging temperatures and aging period of dry-aged chicken breast subjected to the electric field supercooling system
Trait Temperature (°C) Dry-aging period (weeks)
0 1 2 3 4 5
L* 0 52.88 ± 0.94a 46.04 ± 1.90Bb 43.85 ± 2.07Bc 42.88 ± 0.84Cc 42.10 ± 0.81Cc NA
−1 52.88 ± 0.94a 47.80 ± 2.30ABb 46.13 ± 1.69ABbc 44.78 ± 0.40Bcd 43.62 ± 0.61Bde 42.04 ± 2.45e
−2 52.88 ± 0.94a 48.84 ±1.09Ab 47.22 ±1.70Ac 46.43 ± 0.70Ac 46.93 ± 0.29Ac 44.00 ± 0.96d
a* 0 1.12 ± 0.28d 2.08 ± 0.36c 3.53 ± 0.98Ab 5.07 ± 0.74Aa 5.67 ± 1.18Aa NA
−1 1.12 ± 0.28d 1.53 ± 0.28cd 1.93 ± 0.71Bcd 2.50 ± 0.62Bc 3.95 ± 1.55Bb 5.84 ± 1.14Aa
−2 1.12 ± 0.28c 1.43 ± 0.95c 1.62 ± 0.51Bc 1.72 ± 0.43Bbc 2.43 ± 0.48Cb 3.68 ± 0.62Ba
b* 0 5.08 ± 0.96d 6.83 ± 1.36c 10.68 ± 2.17Ab 11.66 ± 0.92Ab 13.09 ± 0.79Aa NA
−1 5.08 ± 0.96d 7.32 ± 0.85c 8.35 ± 0.39ABb 8.70 ± 0.42Bab 8.82 ± 0.45Bab 9.57 ± 0.85a
−2 5.08 ± 0.96d 6.61 ± 0.96c 7.69 ± 1.57Bbc 8.32 ± 0.67Bab 8.57 ± 0.66Bab 9.33 ± 1.09a

All values are mean ± SD.

Means in the same row with different numbers are significantly different (p < 0.05).

Means in the same column with different numbers are significantly different (p < 0.05).

NA, Not applicable.

Download Excel Table
Thiobarbituric acid reactive substance

Table 2 shows the TBARS levels based on the aging temperatures and aging periods of dry-aged chicken breast subjected to the EFSS. TBARS increases owing to the production of MDA, a secondary product, as fat in meat is oxidized [22], and the TBARS values of all treatments tended to increase as the aging period increased. However, there was no significant difference between the 0°C and −1°C treatments from the 1st week to the 4th week. This is because Ross 708 broiler breast has a low content of fat that can be oxidized, with a fat content of approximately 0.78%–2.53% [23]. de Paula et al. [24] reported that meat with TBARS exceeding 1.0 mg MDA/kg can feel rancid when ingested; however, all treatments showed TBARS values less than 1.0 mg MDA/kg during the aging period, so it is suggested to be an appropriate level for consumption. The −2°C treatment showed significantly lower TBARS than the 0°C and −1°C treatments at the 1st and 5th week, respectively (p < 0.05). Kang et al. [8] reported that the lower the aging temperature of meat, the slower the production rate of MDA could be, and the TBARS value was lower in the −2°C treatment with a lower aging temperature. Therefore, when the chicken breast was dry-aged by applying the EFSS, the TBARS value showed a slight increase; however, since the final level showed a level suitable for consumption, it is suggested that aging is possible at any temperature.

Volatile basic nitrogen

Table 5 shows the VBN levels based on the aging temperatures and aging periods of dry-aged chicken breast subjected to the EFSS. The VBN values of all treatments showed a tendency to increase as the aging period elapsed, and the 0°C treatment showed a significant increase based on the aging period (p < 0.05). The increase in the VBN value is caused by the decomposition of proteins by endogenous enzymes and microbial enzymes during the dry-aging process, and the formation and accumulation of protein-derived basic products such as amines and ammonia [25]. The VBN value of the 0°C treatment was significantly higher than that of the −1°C and −2°C treatments in the 1st, 2nd, and 4th weeks (p < 0.05). This is suggested to be the result that the 0°C treatment with a high aging temperature is relatively suitable for microbial growth, and the level of protein degradation by microbial enzymes is high. This is a result of the fact that the 0°C treatment with a high aging temperature is relatively suitable for microbial growth, and the level of protein degradation by microbial enzymes is high. Mentioned by the Ministry of Food and Drug Safety [26], if the VBN value is less than 20 mg% g, it is treated as fresh meat. After dry aging, the final VBN values of the treatments for each temperature were 4.76 mg%, 3.17 mg%, and 2.52 mg%, respectively. Therefore, dry-aging of chicken breasts by applying an EFSS is suggested to be suitable for consumption because the final VBN value corresponds to fresh meat at all temperatures. In addition, since the −2°C treatment showed the lowest level, it is suggested to be the optimal dry aging temperature.

Table 5. Thiobarbituric acid reactive substances (TBARS, mg malondialdehyde/kg meat) and volatile basic nitrogen (VBN, mg%) based on the aging temperatures and aging period of dry-aged chicken breast subjected to the electric field supercooling system
Trait Temperature (°C) Dry-aging period (weeks)
0 1 2 3 4 5
TBARS 0 0.26 ± 0.04b 0.34 ± 0.04Aa 0.37 ± 0.01a 0.35 ± 0.02a 0.34 ± 0.02a NA
−1 0.26 ± 0.04c 0.33 ± 0.01ABb 0.37 ± 0.04b 0.34 ± 0.01b 0.33 ± 0.02b 0.50 ± 0.06Aa
−2 0.26 ± 0.04d 0.30 ± 0.02Bcd 0.34 ± 0.02bc 0.33 ± 0.02bc 0.35 ± 0.01ab 0.39 ± 0.01Ba
VBN 0 1.26 ± 0.28e 1.96 ± 0.32Ad 2.52 ± 0.32Ac 3.50 ± 0.28Ab 4.76 ± 0.32Aa NA
−1 1.26 ± 0.28b 1.31 ± 0.32Bb 1.40 ± 0.32Bb 2.99 ± 0.32Aa 2.99 ± 0.32Ba 3.17 ± 0.32Aa
−2 1.26 ± 0.28c 1.26 ± 0.28Bc 1.40 ± 0.32Bc 1.96 ± 0.32Bb 2.52 ± 0.32Ba 2.52 ± 0.32Ba

All values are mean ± SD.

Means in the same row with different numbers are significantly different (p < 0.05).

Means in the same column with different numbers are significantly different (p < 0.05).

NA, Not applicable.

Download Excel Table
Aerobic bacteria

Table 6 shows the aerobic bacteria levels based on the aging temperatures and aging periods of dry-aged chicken breast subjected to the EFSS. The levels of aerobic bacteria in all treatments tended to increase, and at the 1st, 2nd, 3rd, and 4th weeks, the −1°C and −2°C treatments showed significantly lower values than the 0°C treatment (p < 0.05). This was due to the growth of aerobic bacteria because the meat was exposed to the air during the dry-aging process, and the growth of microorganisms was smooth owing to the relatively high aging temperature in the 0°C treatment [27]. A high level of microbial growth in meat can cause an off-odor and discoloration, which can reduce quality; therefore, care is needed [28]. Moller et al. [29] reported that the number of aerobic bacteria in chicken meat starts to decay at a level of 6 log/CFU, and Spyrelli et al. [30] reported that the shelf life of chicken meat ends when the levels of aerobic bacteria exceed 7 log/CFU. Therefore, since the number of aerobic bacteria exceeded 7 log/CFU from the 3rd week of the 0°C treatment, it was determined that intake was impossible. In addition, since the −1°C and −2°C treatments exceeded 6 log/CFU from the 4th week, aging up to the 3rd week is considered to be microbiologically safe.

Table 6. Aerobic bacteria (Log CFU/g) levels based on the aging temperatures and aging period of dry-aged chicken breast subjected to the electric field supercooling system
Trait Temperature (°C) Dry-aging period (weeks)
0 1 2 3 4 5
Aerobic bacteria 0 3.13 ± 0.19c 5.65 ± 0.29Ab 5.75 ± 0.18Ab 7.49 ± 0.68Aa 7.62 ± 0.70Aa NA
−1 3.13 ± 0.19f 3.85 ± 0.40Be 4.77 ± 0.06Bd 5.38 ± 0.16Bc 6.36 ± 0.14Bb 6.64 ± 0.26a
−2 3.13 ± 0.19d 3.37 ± 0.32Bd 4.60 ± 0.24Bc 5.47 ± 0.43Bb 6.25 ± 0.41Ba 6.52 ± 0.37a

All values are mean ± SD.

Means in the same row with different numbers are significantly different (p < 0.05).

Means in the same column with different numbers are significantly different (p < 0.05).

NA, Not applicable.

Download Excel Table

CONCLUSION

This study, an EFSS to chicken breast and dry-aged it at three temperatures (0°C, −1°C, and −2°C) to set the optimal aging temperature and period. The aging loss and trimming loss of chicken breast could be minimized when dry-aged at −2°C. Because the WHC of some treatments is not measured due to excessive drying and is inappropriate for intake, it is considered appropriate to age at 0°C, −1°C, and −2°C for up to 3, 4, and 5 weeks, respectively. TBARS and VBN showed safe levels at all temperatures, even at the end of aging, but the −2°C treatment showed the lowest value. The level of aerobic bacteria in the 0°C treatment was shown to be contaminated from the 3rd week, and the level of aerobic bacteria in the −1°C and −2°C treatments was showed as less than 7 log/CFU in all aging periods. Therefore, considering the physicochemical and storage properties, it is most appropriate to dry-aged chicken breast at −2°C for 3 weeks using the EFSS.

Competing interests

No potential conflict of interest relevant to this article was reported.

Funding sources

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (KRF), funded by the Ministry of Education (2018R1D1A1B07049938).

Acknowledgements

Not applicable.

Availability of data and material

Upon reasonable request, the datasets of this study can be available from the corresponding author.

Authors’ contributions

Conceptualization: Jeong CH, Lee SH, Kim HY.

Data curation: Jeong CH.

Formal analysis: Jeong CH.

Methodology: Jeong CH.

Software: Jeong CH.

Validation: Jeong CH.

Investigation: Jeong CH, Lee SH, Kim HY.

Writing - original draft: Jeong CH.

Writing - review & editing: Jeong CH, Lee SH, Kim HY.

Ethics approval and consent to participate

This article does not require IRB/IACUC approval because there are no human and animal participants.

REFERENCES

1.

Ala MAN, Shahbazi Y. The effects of novel bioactive carboxymethyl cellulose coatings on food-borne pathogenic bacteria and shelf life extension of fresh and sauced chicken breast fillets. LWT. 2019; 111:602-11

2.

Garavito J, Moncayo-Martínez D, Castellanos DA. Evaluation of antimicrobial coatings on preservation and shelf life of fresh chicken breast fillets under cold storage. Foods. 2020; 9:1203

3.

Petrou S, Tsiraki M, Giatrakou V, Savvaidis IN. Chitosan dipping or oregano oil treatments, singly or combined on modified atmosphere packaged chicken breast meat. Int J Food Microbiol. 2012; 156:264-71

4.

Álvarez S, Álvarez C, Hamill R, Mullen AM, O’Neill E. Drying dynamics of meat highlighting areas of relevance to dry-aging of beef. Compr Rev Food Sci Food Saf. 2021; 20:5370-92

5.

Bhat ZF, Morton JD, Mason SL, Bekhit AEDA. Role of calpain system in meat tenderness: A review. Food Sci Hum Wellness. 2018; 7:196-204

6.

Shi Y, Zhang W, Zhou G. Effects of different moisture-permeable packaging on the quality of aging beef compared with wet aging and dry aging. Foods. 2020; 9:649

7.

Mok JH, Her JY, Kang T, Hoptowit R, Jun S. Effects of pulsed electric field (PEF) and oscillating magnetic field (OMF) combination technology on the extension of supercooling for chicken breasts. J Food Eng. 2017; 196:27-35

8.

Kang KM, Lee SH, Kim HY. Changes in physico-chemical and storage properties of dry-aged beef loin using electric field refrigeration system. Foods. 2022; 11:1539

9.

Stonehouse GG, Evans JA. The use of supercooling for fresh foods: a review. J Food Eng. 2015; 148:74-9

10.

Kim HS, Lee SH, Kim HY. Physicochemical properties of dry aged chicken breast applicate electric field super cooling system. J Korean Soc Food Sci Nutr. 2020; 49:984-90

11.

Barbera S. WHCtrend, an up-to-date method to measure water holding capacity in meat. Meat Sci. 2019; 152:134-40

12.

Jeong CH, Lee SH, Yoon Y, Choi HY, Kim HY. Identification of optimal fermentation temperature for dry-fermented sausage using strains isolated from Korean fermented foods. Foods. 2023; 12:137

13.

Conway EJ, O’malley E. Microdiffusion methods. Ammonia and urea using buffered absorbents (revised methods for ranges greater than 10 μg. N). Biochem J. 1942; 36:655-61

14.

Berger J, Kim YHB, Legako JF, Martini S, Lee J, Ebner P, et al. Dry-aging improves meat quality attributes of grass-fed beef loins. Meat Sci. 2018; 145:285-91

15.

Cho S, Kang SM, Kim YS, Kim YC, Van Ba H, Seo HW, et al. Comparison of drying yield, meat quality, oxidation stability and sensory properties of bone-in shell loin cut by different dry-aging conditions. Korean J Food Sci Anim Resour. 2018; 38:1131-43

16.

Berardo A, Claeys E, Vossen E, Leroy F, De Smet S. Protein oxidation affects proteolysis in a meat model system. Meat Sci. 2015; 106:78-84

17.

Kaur L, Hui SX, Morton JD, Kaur R, Chian FM, Boland M. Endogenous proteolytic systems and meat tenderness: influence of post-mortem storage and processing. Food Sci Anim Resour. 2021; 41:589-607

18.

Kaur L, Hui SX, Boland M. Changes in cathepsin activity during low-temperature storage and sous vide processing of beef brisket. Food Sci Anim Resour. 2020; 40:415-25

19.

Nuñez SM, Cárdenas C, Pinto M, Valencia P, Cataldo P, Guzmán F, et al. Bovine skin gelatin hydrolysates as potential substitutes for polyphosphates: the role of degree of hydrolysis and pH on water-holding capacity. J Food Sci. 2020; 85:1988-96

20.

Zhang L, Sun JY, Shen XJ, Zhang YM, Che H, Ma QL, et al. Observations of relative humidity effects on aerosol light scattering in the Yangtze River Delta of China. Atmos Chem Phys. 2015; 15:8439-54

21.

Calnan H, Jacob RH, Pethick DW, Gardner GE. Production factors influence fresh lamb longissimus colour more than muscle traits such as myoglobin concentration and pH. Meat Sci. 2016; 119:41-50

22.

Wang Z, He Z, Emara AM, Gan X, Li H. Effects of malondialdehyde as a byproduct of lipid oxidation on protein oxidation in rabbit meat. Food Chem. 2019; 288:405-12

23.

Petracci M, Mudalal S, Babini E, Cavani C. Effect of white striping on chemical composition and nutritional value of chicken breast meat. Ital J Anim Sci. 2014; 13:3138

24.

de Paula R, Colet R, de Oliveira D, Valduga E, Treichel H. Assessment of different packaging structures in the stability of frozen fresh Brazilian toscana sausage. Food Bioprocess Technol. 2011; 4:481-5

25.

Lee HJ, Choe J, Yoon JW, Kim S, Oh H, Yoon Y, et al. Determination of salable shelf-life for wrap-packaged dry-aged beef during cold storage. Korean J Food Sci Anim Resour. 2018; 38:251-8

26.

Ministry of Food and Drug Safety. Standards and specifications for each food [Internet]. 2023.[cited 2023 Feb 28]https://www.foodsafetykorea.go.kr/foodcode/03_02.jsp?idx=37.

27.

Choe JH, Stuart A, Kim YHB. Effect of different aging temperatures prior to freezing on meat quality attributes of frozen/thawed lamb loins. Meat Sci. 2016; 116:158-64

28.

Attala OA, Assaggaf HM, Alsafi RT, Ahmed OB. Efficacy of oleoresins of ginger and rosemary to improve the oxidative stability and sensory attributes in non-irradiated and irradiated minced meat. J Saudi Soc Food Nutr. 2020; 13:127-37

29.

Moller A, Leone C, Kataria J, Sidhu G, Rama EN, Kroft B, et al. Effect of a carrageenan/chitosan coating with allyl isothiocyanate on microbial spoilage and quality of chicken breast. Poult Sci. 2023; 102:102442

30.

Spyrelli ED, Papachristou CK, Nychas GJE, Panagou EZ. Microbiological quality assessment of chicken thigh fillets using spectroscopic sensors and multivariate data analysis. Foods. 2021; 10:2723