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Article

Physiochemical Properties and Oxidation Status of Pork from Three Rearing Systems

by
Fouad Ali Abdullah Abdullah
1,2,*,
Michaela Trnková
1 and
Dani Dordevic
3
1
Department of Food Hygiene and Technology of Animal Origin and Gastronomy, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences Brno, Palackého Tř. 1946/1, 612 42 Brno, Czech Republic
2
Department of Medical Laboratory Technology, College of Health and Medical Techniques, Duhok Polytechnic University, Duhok 42001, Iraq
3
Department of Plant Origin Food Sciences, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences, 612 42 Brno, Czech Republic
*
Author to whom correspondence should be addressed.
Appl. Sci. 2023, 13(17), 9731; https://doi.org/10.3390/app13179731
Submission received: 7 July 2023 / Revised: 14 August 2023 / Accepted: 27 August 2023 / Published: 28 August 2023
Review Reports Versions Notes

Abstract

:
The consumer’s interest in his/her health and the quality of his/her food has increased as well as in environmental issues such as animal welfare. Consumers believe that organic and similar (traditional) production systems are more advantageous for consumers (providing healthier food) and animals (providing better welfare). The aim of the study was to evaluate the impact of different rearing systems (organic, conventional and traditional) on the physicochemical properties and oxidation states of pork meat. The meat samples were obtained from three different rearing systems of pigs: organic, conventional and traditional. The samples (M. biceps femoris) were obtained from producers directly 3 days after slaughtering for analysis. The following physical and chemical parameters were analyzed: color (according to the CIE L * a * b * system), pH, dry matter, protein, collagen, fat and ash. The oxidation state of the meat samples was measured by thiobarbituric acid reactive substances (TBARSs), free fatty acid (FFA) and antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl). The results indicated that the rearing system affects most of the evaluated parameters. A significant difference (p < 0.05) was observed in color parameters L* and b*, where the conventional pork samples were darker and the organic pork yellower. Total protein content in meat of pigs raised in a conventional system was higher (22.23%) than for organic (20.36%) and traditional (21.21%). The fat content in the meat of organically reared pigs was higher (2.81%) than in pork from conventional and traditional systems (1.43% and 0.37%, respectively). Organic pork was more susceptible to oxidation processes due to its higher TBARS (1.24 mg/kg) and FFA (1.15% fat as oleic acid) values and lower antioxidant capacity (26.42% inhibition), which may result in inferior technological properties of meat.

1. Introduction

Global pork consumption accounts for 33% of total meat consumption, with large differences among continents in consumption levels [1]. The European Union (EU countries) accounts for 21% of the world production of pork. Recently, there has been a great increase in pork products that are sold with official quality labels and the number of pigs that are produced under alternative production systems [2]. Quality of pork is based on several quality attributes: nutritional, organoleptic and technology (oxidation status during storage and thus shelf life) properties and societal image (animal welfare and environmental impacts) [3]. The traditional rearing methods of the past allowed pigs to range freely during the day and sleep in a spacious pigsty at night. In recent decades, these old traditional methods have been replaced by intensive rearing (conventional) systems in which the pigs are continuously confined in a restricted, stimulus-poor space [4]. However, not only whole food safety and the sensory quality of pork but also the life quality of pigs in rearing systems are very important to consumers and have become a major point of concern as well [5]. Furthermore, it is a common belief among consumers that the quality of pork from pigs raised under extensive systems is better [6]. This led to increased interest in alternative rearing systems such as outdoor, free range and organic production systems. Organic farming is the most regulated alternative production system, providing environmental sustainability and welfare for breeding animals [7]. The rules of organic production systems, encompassing a comprehensive set of guidelines and regulations, are explicitly outlined and defined within the extensive body of European Union legislation. These regulations address critical factors, such as the optimal housing conditions, comprising both indoor and outdoor areas, the intricacies of feeding practices, the consideration of age as a vital determinant and the specific genotype attributes of animals involved in organic production [8]. The core point of rearing system differences is the availability of outdoor areas for animals. Roles of outdoor areas can be summed up mainly by pigs’ physical activity, better animal welfare and feed quality (ingestion of herbage and soil in the pasture) which could be reflected in the quality and quantity of meat [9]. Another factor that can play a role through rearing systems in the production properties and meat quality is genotype. Local breeds of pigs are considered to be most suitable for outdoor production systems. On the other side, these local breeds are characterized by inferior carcass qualities, low feed consumption efficiency and growth efficiency in comparison with specialized breeds raised in conventional systems [10]. Rearing conditions of pigs under alternative systems (free range and organic systems, outdoor access) increase energy expenditure for physical activity and thermoregulation, decreasing the growth rate, but improve some properties of meat quality such as the production of lean meat and higher meat oxidative stability [11]. In contrast, other authors indicated that higher intramuscular fat and unsaturated fatty acid composition in organic pork enhanced lipid oxidation, resulting in inferior technological meat quality [12,13,14]. Furthermore, it is worth noting that an abundance of investigations and extensive studies have been conducted to explore the multifaceted impacts of various pig rearing systems on both the quantitative aspects and qualitative attributes of pork, encompassing even the intricate evaluation of pork’s oxidation status. Remarkably, the findings stemming from these comprehensive examinations have demonstrated a remarkable divergence, thereby yielding a broad spectrum of outcomes and conclusions that often diverge significantly from one another, thus further accentuating the complex nature of this research domain [9,11,15,16,17]. The contradictory conclusions could be attributed to large differences in the design of the rearing systems [18].
The aim of the study was to clarify the difference in physicochemical properties and oxidation status in pig meat originating from three rearing systems (organic, conventional and traditional).

2. Materials and Methods

2.1. Rearing Conditions of Animals and Sample Preparation

Samples of meat were obtained directly from breeders at their slaughterhouses. The samples of organic pork were from Biofarma Sasov (Sasov 2, 58601 Jihlava, Czech Republic), conventional pork from slaughterhouse Šebkovice, s.r.o. (Šebkovice, 675 45, Czech Republic) and traditional pork were from Farma rodiny Němcovy (Netín 78, 594 44 Radostín nad Oslavou, Czech Republic). Information about the age and weight of pigs at slaughter as well as the genotypes of pigs is shown in Table 1.
Organic pig farming: after birth, piglets stayed with their mothers till 35 days of age, then with their mothers were moved to the stables. In these stables, there are usually 5 to 6 sows with piglets and always 1 boar. Piglets were fed sow milk that provides them nutrition and protection against diseases. The animals had constant access to the outdoors to encourage natural life processes as in nature. Weaning occurred at 3 months of age of the piglets. After weaning, the piglets remained in the same environment, in the same stable as before. The period of feeding was 7 months. Feed rations were balanced, full-value, composed exclusively of organic feed and the permitted amount of permitted conventional feed—no extracted meal, no meat-and-bone meal, growth promoters, hormonal substances, synthetic amino acids, antibiotics, etc. Ecological slaughter was ensured by slaughterhouses directly on the farm. During all movements within the farm, the pigs walk on their own and are not stressed by transport, including the journey to the slaughterhouse. The entire breeding process of livestock on the farm is based on the greatest possible animal welfare and their most natural living conditions.
Conventional pig farming: after birth, piglets stay with their mothers for the first 3 weeks of their lives. Consequently, the weaning was conducted at the earliest at 3 weeks of age. Then, animals were divided into groups according to sex and breeding plan immediately after weaning. Pigs were in permanently closed stables with controlled air conditioning. Animals were grown (for 6 months of their life) in the region of Vysocina, Sebkovice, the Czech Republic. The conditions in the housing were the following: minimum pen area for one animal according to the weight: up to 50 kg = 0.40 m2; up to 85 kg = 0.55 m2; up to 110 kg = 0.70 m2.
Traditional pig farming: the farm is located in the Vysočina region (village of Netín). The farm operates on 150 hectares of agricultural land and owns approx. 70 pigs of the Prestice Black-Pied breed. The farm combines modern technology with rural experience and skills. The Prestice Black-Pied genotype is the original Czech breed [19] and is appropriate for use on small farms and organic system production. This genotype is not suitable for conventional systems and on large farms. The growth period was extended to 7 months; pigs received a tailor-made feed ration without use of GMO feed.
Sample preparation: a total of 30 samples (out of 30 individual barrows) from three different rearing systems were used for analysis. Ten meat samples of about 150 g from M. biceps femoris were taken from each farm. The meat samples were transported in a cold atmosphere (around 4 °C) to the University of Veterinary Sciences Brno where the analyses were conducted. Physicochemical and oxidative analysis was performed 3 days after slaughtering. The samples for antioxidant capacity analysis were stored (in a vacuum atmosphere) in the freezer at −70 °C until the day of analysis.

2.2. Physical Property Evaluation

The color indicators (lightness L *; redness a *; yellowness b *; chroma saturation C* = (a*2 + b*2)0.5; hue angle h° = tan−1(b*/a*)) of the muscle surface were measured according to the CIE L * a * b * system, with the use of a CM-5 spectrophotometer instrument (Konica Minolta Sensing, Inc., Sakai Osaka, Japan). The SpectraMagic NX Color Data software (CM-S100w 2.03.0006, 2003–2010) was used to calculate the variables, the mean and the standard deviation of five measurements for each sample was recorded. For the determination of pH, 5 g of meat from each sample was placed in a Stomacher bag containing 15 mL of distilled water and was homogenized for 2 min. The following pH meter was used: Thermo Scientific Orion 4-Star Benchtop pH/ISE Meter.

2.3. Chemical Composition

The meat samples were minced in order to be used for assay of chemical composition. The amount of dry matter was determined gravimetrically by drying the sample for 24 h at 103 ± 2 °C according to ISO 1442 [20]. Determination of total protein was performed by using a Kjeltec 2300 (FOSS Analytical AB, Hilleroed, Denmark) in three consecutive steps: mineralization, steam distillation, titration of the sample. Mineralization of the sample in concentrated H2SO4 leads to (NH4)2SO4 formation from available nitrogen. In a basic environment of 30% KOH, NH3 is formed from (NH4)2SO4 and leads into 0.1 mol·dm−3 HCl that is partly neutralized by ammonium. The exact amount of nitrogen can be calculated from the amount of neutralized HCl. A conversion factor of 6.25 was used. The determination was performed according to ISO 937 [21]. Collagen was calculated (coefficient f = 8) using the amino acid hydroxyproline. Hydroxyproline was determined by a spectrophotometer via measuring absorbance at 550 nm on a GENESYSTM6 instrument (Thermo Electron Corporation, Waltham, MA, USA). The method was performed according to the SOP [22]. Determination of fat was performed analytically using SOXTEC 2055 (FOSS Analytical AB, Hilleroed, Denmark). Petroleum ether was used as the solvent. The analysis was performed according to ISO 1443 [23]. Carbohydrates were mathematically calculated using the following formula: carbohydrates = dry matter − (total protein + fat + ash). The ash was determined gravimetrically by burning the sample in a muffle oven (Elektro LM 212.11, Kaiserslautern, Germany) at 550 °C until the black particles in the ash completely disappeared, according to ISO 936 [24].

2.4. Oxidation Status Evaluation

Thiobarbituric acid reactive substances (TBARSs): the extent of lipid oxidation was evaluated and determined as TBARS. First, 10 g of minced meat samples was homogenized for 2 min with 95.7 mL of distilled water and 2.5 mL of 4 M HCl. The samples were distilled until a 50 mL distillate was obtained. Then, 5 mL of 15% trichloroacetic acid, 0.375% thiobarbituric acid reagent was added to 5 mL of distillate and the mixture was heated in a boiling water bath for 35 min. The samples were left to cool then absorbance of the samples was measured at 532 nm by a spectrophotometer, against an appropriate blank. TBARS values were obtained by multiplying the absorbance value by 7.8. Oxidation products were quantified as malondialdehyde equivalents (MDA mg·kg−1) [25]. Free fatty acids (FFAs): determination was performed by the titration method according to CSN EN ISO 660 (588756) [26] and expressed as the percentage of total fat as oleic acid. Antioxidant capacity: the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method was used for the determination of the antioxidant capacity [27]. Sample preparation was according to Jung et al. [28] by homogenizing 3 g of sample (minced meat) with 15 mL of 5% trichloroacetic acid, then 10 mL of chloroform was added. DPPH in methanol (0.025 g/L) was dissolved in order to prepare a fresh solution of radical stock. This fresh solution of DPPH was measured by a spectrophotometer against a blank at 515 nm, and the obtained result (absorbance value) was recorded (A0). A sample of meat extract (0.2 mL) was added to DPPH solution (3.8 mL) and the absorbance was measured (A10) after 10 min. The percentage of inhibition for the DPPH radical was calculated according [27] to the following formula:
DPPH (%) = [(AbsA0DPPH − AbsA10DPPH)/AbsA0DPPH] × 100

2.5. Statistical Analyses

Statistical analysis was conducted by one-way ANOVA, in which statistical significance at p < 0.05 was determined. A parametric Tukey post hoc test (when a Levene test showed no significant difference p > 0.05) and nonparametric Games–Howel (when a Levene test showed a significant difference p < 0.05) post hoc test were used to find differences between groups. SPSSstatistical software, version 21 (IBM Corporation) was used for the statistical evaluation.

3. Results

For finding and emphasizing differences between included rearing systems, the obtained results represented the following analyses: physical properties (color attributes and pH), chemical analysis (dry matter, total protein content, collagen, fat, carbohydrates and ash content) and oxidation parameters (TBARS, free fatty acids and antioxidant capacity). This section is divided into corresponding subsections.

3.1. Physical Properties

The results of the color data and pH are shown in Table 2. The results showed that the meat of organically and traditionally raised pigs was significantly (p < 0.05) lighter in color (higher L* values) than conventionally raised pork. The redness indicator (a*) was lower (not statistically significant) in traditional pork than in organic and conventional pork. Pork from organic pigs was significantly (p < 0.05) yellower (higher b* values) than conventional and conventional pork. C* values of conventional and traditional samples were lower significantly (p < 0.05) in comparison with the organic samples. Pork originating from organic rearing systems had the lowest pH value (p < 0.05), with no statistically significant differences between conventional and traditional samples.

3.2. Chemical Composition

Chemical composition results are explained in Table 3. Pork from conventional systems contained more (p < 0.05) dietary fiber than traditional pork, whereas no significant differences were found between organic pork and both conventional and traditional pork. The total protein content of organic and traditional pork was significantly lower (p < 0.05) than that of conventional pork. The results showed that organic meat had a higher collagen content, though not statistically significant (p > 0.05). The fat content of organic pork was significantly higher (p < 0.05) than of conventional and traditional pork. Traditional pork contained less carbohydrate (p < 0.05) than organic and conventional pork. Ash content was in the range of 1.18% to 1.38%, while statistically significant differences between rearing systems were not obtained (p > 0.05).

3.3. Oxidation Status

The results of oxidative status (TBARS, free fatty acids and antioxidant capacity) are shown in Table 4. TBARS, expressing secondary oxidation, of organic and conventional meat was higher (p < 0.05) than in traditional meat. The good oxidation stability (low TBARS values) of the traditional pork samples can be considered as a positive property, giving such meat priority to be used, especially for the production of different meat commodities. Susceptibility of organic pork to oxidation processes is confirmed not only by the results of TBARS but also by the results of free fatty acids and antioxidant capacity. Free fatty acids in organic pork were the highest, followed by traditional and conventional pork. The antioxidant capacity of organic pork was lower (p < 0.05) than that of conventional and traditional pork.

4. Discussion

The growth rate of organic and traditionally raised pigs was lower compared to conventionally raised pigs. Pigs from conventional rearing reached a higher weight (110–120 kg) in a relatively shorter rearing period (6 months) (Table 1). The slow growth of organically raised pigs could be due to higher energy requirements for activity and thermoregulation. Access to outdoor exercise is a basic principle of organic farming, and free-range housing provides animals with the opportunity for greater physical activity than in the conventional system. Conventional pigs are kept in groups in much smaller spaces, without access to outdoor areas, and may have higher energy content in their diets, resulting in higher daily gains [16,18]. Although the same genotype (slow growth) of pigs was used in both organic and conventional production systems, the weight at the slaughter age (7 months) of traditional pigs was higher (90–100 kg) than the weight of organic pigs (80 kg). This in turn raises a question about the range of locomotor activity and feeding regimen of these pigs under these rearing systems. However, carcass composition is affected by the interaction of pig feeding with housing conditions [29]. Pig genotype also plays an important role in production traits (live weight and growth rate). Commercial hybrids are often used in intensive rearing systems (conventional systems) due to their fast growth rate and adaptability to limited space. In contrast, alternative rearing systems such as organic and free range are more suited to slow-growing pig strains with high adaptability to different environmental conditions [11,30].

4.1. Physical Properties

Color is an important attribute of meat quality for consumers. The results of meat brightness (L* value) in our work are in agreement with those of Tomažin et al. [31], as meat from organic pigs was brighter than that from conventional pigs. In that study [31], it was found that the meat from organic pigs had higher CIE L*, a* and b* values than the meat from conventionally raised pigs. In contrast, Olsson and Pickova [32] reported that the meat from organically raised pigs was darker/redder in color, but the study acknowledged that the evidence for this was inconclusive. Castellini et al. [25] found that higher levels of animal welfare under organic farming reduce stress conditions and lead to reduced pH (lower levels of glycogen catabolized to lactic acid), and as a result the lightness value (L*) of organic meat increases. Our results are in line with this idea, as the pH of organic pork was significantly lower which elevated the L* value. Although redness scores (a*) of organic meat were the highest, the difference was not significant (p > 0.05). Redder pork from organic systems could be attributed to a higher content of myoglobin. Heme pigments normally increase with age [33], and organically reared pigs are usually older at slaughter than pigs from conventional production systems (Table 1).
Nevertheless, it is imperative to highlight that, as elucidated by the previous research [29], the conditions inherent to extensive production systems, characterized by outdoor access and free-range opportunities, have been found to yield remarkable enhancements in the organoleptic quality of pork. This encompasses a host of desirable attributes, with one noteworthy aspect being the attainment of a vividly more intense reddish hue in comparison to the pork derived from conventional rearing conditions. The greater yellowing of organic meat could be due to the feeding of pigs in the organic system and, in particular, the intake of grass in the free-range system. Organically raised pigs consume a greater amount of vegetable feed containing carotenoid pigments [34,35]. The fat content is also related to the yellow color of the meat. Our result showed that the meat from organic pigs had the highest values in fat content, which could be the reason for the more yellowish color. The yellowish color of the meat is also due to the high intramuscular lipid content and the incorporation of lipophilic pigments [36].

4.2. Chemical Composition

It is important to acknowledge that the impact of pig housing systems on the chemical composition of pork has been the subject of extensive investigation, yet the findings derived from published studies have exhibited a notable lack of consistency and uniformity [32]. In the present study, significant differences in dry matter, protein, fat and carbohydrate content were found in the meat of pigs from different housing systems. In contrast, no significant differences were found in dry matter, protein, fat and ash content in meat from pigs raised in free-range or conventional systems by Hoffman et al. [37]. The higher protein content in conventional pork and the higher fat content in organic pork are not in accordance with the previous studies, indicating the necessity to carry out more research and compare different breeds, including individual rearing systems in different regions [38,39,40]. This statement is supported by other previous studies: higher intramuscular fat content was found in organic pork by Sundrum et al. [13]. The collagen content of organic pork tended to be higher (not significant, p > 0.05) than that of meat from conventionally and traditionally raised pigs, which could be attributed to the motor activity of the animals [18]. The idea that motor activity prioritizes myogenesis over lipogenesis [25] is more consistent with the results of pork from traditional rearing systems (higher portion vs. lower fat content) than organic pork in the study. These findings raise a question about the extent of the physical activity of animals in outdoor areas under organic production systems. The physical activity of organically raised animals primarily affects the metabolic state of the muscles at slaughter, whereas it has a limited effect on the chemical composition of the meat. The influence of the husbandry system on the chemical composition of the meat is often due to differences in feed composition and intake, as well as the energy required to maintain the animals [32]. Biochemical and metabolic properties inherent to pig muscles undergo significant transformations as a result of the physical activity stimulation imposed upon them, further compounded by the confluence of ambient temperatures within extensive rearing systems [41,42]. It is crucial to recognize that the interplay between these multifaceted factors encompasses an integration that intricately intertwines the physiological responses of the pig’s musculature with the prevailing environmental conditions [43]. The energy content of the feed according to organic standards, combined with a mild climate during animal production, could be the reason for the thicker meat of the organic pigs in this work. The higher fat content of organic pork may also be attributed to the genotype of the pigs used for breeding. In contrast, the genotype of the pigs used in the conventional system is a meat type and the fat content is not as high, even at a higher slaughter weight.

4.3. Oxidation Status

Lipid oxidation is one of the main causes of meat deterioration, leading to the formation of compounds that are potentially harmful to human health. The initiation and propagation of lipid oxidation may occur due to the imbalance between pro- and antioxidant substances that occurs during the conversion of muscle into edible meat after slaughter [44]. The notable presence of elevated TBARS levels and correspondingly diminished antioxidant capacity observed in organic pork specimens provides insights into biochemical dynamics at play. These distinctive observations may be attributed to the organic production system’s inherent challenge of achieving and sustaining a delicate equilibrium between pro-oxidant and antioxidant factors, wherein the intricate interplay between these opposing forces becomes disrupted, potentially leading to an imbalance that manifests as the higher TBARS levels and reduced antioxidant capacity witnessed within our experimental framework. Tomažin et al. [31] indicated that the higher TBARS levels in meat from organic pigs may be related to the lack of vitamin E (lipid oxidation inhibitor) for antioxidant protection of PUFA. The higher TBARS levels and lower antioxidant (vitamin E) content in meat from organically raised pigs corresponded to the higher intake of polyunsaturated fatty acids reflected in the meat [16]. Free fatty acids may have a pro-oxidant effect on lipid substances, which have a catalytic effect for the carboxyl group in the formation of free radicals during the decomposition of hydroperoxides [45,46]. According to the results of FFA in our study, meat from organic pigs was more susceptible to lipid oxidation than meat from traditional and conventional pigs. High oxidative stability of the meat required low TBARS and FFA values [46,47]. However, a higher lipid oxidation was observed in organic meat by Martino et al. [11] and Nilzén et al. [14]. Results of higher lipid oxidation of organic meat in this study were expected due to greater physical activity of animals and high peroxidability index [25]. More oxidation stability of pork from traditional systems in comparison with organic pork was observed. Differences in oxidation stability between the pork from traditional and organic rearing systems may be related to the level of kinetic activity of these pigs (in outdoor areas) on one side and feeding regimen (pasture grazing is the source of antioxidant substances) on the other side [25,34,35]. The lower antioxidant capacity observed in meat from organic pigs in this study may be due to its involvement in controlling oxidation processes in the body of a live animal, thus depleting its reserves in the meat after slaughter. Kouba et al. [48] found that the low level of antioxidants (vitamin E) in pig tissues containing high concentrations of PUFA was due to the use of antioxidants to control oxidative processes. However, it should be underlined that important factors affecting oxidative stability are also the diet, sex and breed of the animal, as well as the storage temperature and fat composition of the meat. This statement emphasizes the complexity of meat properties, including oxidative stability, that can be affected by multiple external and internal factors [46,47].

5. Conclusions

The study compares the properties of pork that are produced from three different production systems (organic, traditional and conventional). Each rearing system is an integrated system, including its conditions related to the age of animals at slaughter, feeding regimen, welfare (indoor/outdoor space available to the animals) and suitable breeds of animal for that rearing system. The results of the study confirmed significant differences in physiochemical properties and oxidation status of pork originating from organic, conventional and traditional farming. The main findings of the study are the following differences: (i) conventional pork was darker and organic pork was more yellow; (ii) conventionally raised pigs had higher protein content, while the meat from organically raised pigs contained higher fat content; (iii) organic pork was more susceptible to oxidation than conventional and traditional pork. Pork from the traditional production system is superior to organic pork in terms of nutritional values (higher protein content and lower fat content) and oxidation stability (lower TBARS and FFA vs. higher antioxidant capacity). It should be underlined that the main potential limitation of the conducted study is certainly sample heterogeneity (from three different rearing systems). Potential limitations in the comparison of the three different rearing systems for pork production include pig breed, feeding regime, housing (available space and access to the outdoors), age and weight at slaughter. Another potential limitation in our work was limiting the analysis to one part of the pig carcass (M. biceps femoris). Indeed, the existence of limitations can affect results. However, the research was designed in such a way that the experiment simulated the real situation, to evaluate and compare the meat as it is produced and provide valuable information for consumers, but the experiment can also serve as a useful foundation for further studies and experiments. Consumers are interested in the quality of meat which is available in the market that is produced from those different systems. Each rearing system (particularly organic and traditional systems) is promoted with positive publicity in terms of product quality and animal welfare. Thus, the information about meat quality from the experiment is certainly important from the point of view of consumers but also for future scientific works.

Author Contributions

Conceptualization, F.A.A.A. and M.T.; methodology, F.A.A.A.; software, F.A.A.A., M.T. and D.D.; validation, F.A.A.A., M.T. and D.D.; formal analysis, F.A.A.A., M.T. and D.D.; investigation, F.A.A.A. and M.T.; resources, F.A.A.A. and M.T.; data curation, F.A.A.A., M.T. and D.D.; writing—original draft preparation, F.A.A.A.; writing—review and editing, D.D.; visualization, F.A.A.A. and M.T.; supervision, F.A.A.A. and D.D.; project administration, F.A.A.A., M.T. and D.D.; funding acquisition, F.A.A.A., M.T. and D.D. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the University of Veterinary Sciences Brno, Palackého tˇr. 1946/1, 612 42 Brno, Czech Republic, institutional research.

Data Availability Statement

All data underlying the study are available from the corresponding authors on reasonable request.

Conflicts of Interest

The authors declare no conflict of interest.

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Table 1. Characteristics of pigs from organic, conventional and traditional rearing systems.
Table 1. Characteristics of pigs from organic, conventional and traditional rearing systems.
Rearing SystemAge (months)Live Weight (kg)Genotype
Organic780Prestice Black-Pied (meat/bacon breed)
Conventional6110–120Czech Improved White (meat type)
Traditional790–100Prestice Black-Pied
Table 2. Physical properties of pork (mean ± SD) from organic, conventional and traditional rearing systems.
Table 2. Physical properties of pork (mean ± SD) from organic, conventional and traditional rearing systems.
ParametersRearing Systems
OrganicConventionalTraditional
L*54.39 ± 3.71 a46.30 ± 2.35 b51.69 ± 3.01 a
a*4.90 ± 1.93 a4.61 ± 1.38 a3.57 ± 1.17 a
b*13.87 ± 1.09 a11.36 ± 0.81 b11.81 ± 1.15 b
C*14.87 ± 1.61 a 12.30 ± 1.12 b12.37 ± 1.31 b
h°71.13 ± 6.07 a68.18 ± 5,27 a73.41 ± 4.57 a
pH5.69 ± 0.10 b5.90 ± 0.16 a5.88 ± 0.12 a
Values in the same row with different superscripts a, b are significantly (p < 0.05) different among organic, conventional and traditional pork.
Table 3. Chemical composition of pork (mean ± SD) from organic, conventional and traditional rearing systems.
Table 3. Chemical composition of pork (mean ± SD) from organic, conventional and traditional rearing systems.
Parameters [%]Rearing Systems
OrganicConventionalTraditional
Dry matter25.13 ± 1.41 ab25.48 ± 1.61 a23.73 ± 0.43 b
Total protein20.36 ± 1.06 b22.23 ± 0.76 a21.21 ± 0.52 b
Collagen0.62 ± 0.230.59 ± 0.190.52 ± 0.09
Fat2.81 ± 1.37 a1.43 ± 0.97 b0.37 ± 0.12 b
Carbohydrates1.85 ± 0.78 a1.45 ± 0.57 a0.77 ± 0.44 b
Ash1.37 ± 0.291.18 ± 0.071.38 ± 0.17
Values in the same row with different superscripts a, b are significantly different among organic, conventional and traditional pork.
Table 4. Oxidation status of pork (mean ± SD) from organic, conventional and traditional rearing systems.
Table 4. Oxidation status of pork (mean ± SD) from organic, conventional and traditional rearing systems.
ParametersRearing Systems
OrganicConventionalTraditional
TBARS [mg/kg]1.24 ± 0.54 a1.00 ± 0.47 a0.41 ± 0.16 b
Free fatty acids1.15 ± 0.17 a0.58 ± 0.10 c0.76 ± 0.18 b
Antioxidant capacity26.42 ± 1.98 b28.24 ± 2.05 a27.50 ± 1.30 a
Values in the same row with different superscripts a, b, c are significantly different among organic, conventional and traditional pork.
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Abdullah, F.A.A.; Trnková, M.; Dordevic, D. Physiochemical Properties and Oxidation Status of Pork from Three Rearing Systems. Appl. Sci. 2023, 13, 9731. https://doi.org/10.3390/app13179731

AMA Style

Abdullah FAA, Trnková M, Dordevic D. Physiochemical Properties and Oxidation Status of Pork from Three Rearing Systems. Applied Sciences. 2023; 13(17):9731. https://doi.org/10.3390/app13179731

Chicago/Turabian Style

Abdullah, Fouad Ali Abdullah, Michaela Trnková, and Dani Dordevic. 2023. "Physiochemical Properties and Oxidation Status of Pork from Three Rearing Systems" Applied Sciences 13, no. 17: 9731. https://doi.org/10.3390/app13179731

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