Pork Slices Research Articles

Indigenous Taste

For the Indigenous Sagada Igorots of upland Cordillera in northern Philippines, domesticated pigs and etag (salted and smoked pork slices) continue to play an important role for rituals and as gastronomic vehicles for constituting and performing social relatedness, reciprocity, and redistributive functions through feasting and sharing. These deep historical practices are largely mediated by the elders of Sagada in the face of various kinds of entanglements with the state and markets over time. I characterize this mixed bundle of communal socio-affective and gastronomic ingredients as “Indigenous taste.” This essay discusses recent substantive socioeconomic changes in Sagada due largely to mass tourism and the impacts they have set in motion for the aforementioned practices, and on how Sagada Igorots negotiate with the outside world under these new historical conditions.

Mechanism underlying the tenderness evolution of stir-fried pork slices with heating rate revealed by infrared thermal imaging assistance

This study aimed to explore the mechanism of cooking intensity on the tenderness of stir-fried pork slices from the perspective of the changes in temperature distribution. Infrared thermal imaging was used to monitor the distribution of temperature. Results showed that the high-level heat (HH) treatment could improve tenderness. When the center temperature increased to 100 °C, the shear force of samples from the low-level heat (LH) group increased by around 3-fold, and HH reduced this upward trend. This result was mainly attributed to the shorter heating time undergone by the HH-treated samples compared to the LH treatment, which resulted in less structural shrinkage and faster passing through the protein denaturation interval of the samples. These changes alleviated temperature fluctuations caused by water loss. This explanation could be confirmed by the results of T2 relaxation time and Fourier transform-infrared spectroscopy (FT-IR). However, the LH treatment caused a slower rise in oil temperature due to more moisture migration, which required the samples to undergo longer thermal denaturation, leading to a deterioration in tenderness. Moreover, histological analysis revealed that the greater integrity of endomysium in the HH group inhibited water loss and oil absorption, which contributed to obtain low-fat meat products with higher tenderness. This study provides support for the industrialization of traditional pork cuisines using oil as the heating medium.

Identification of bone fragments embedded in lean pork slices by comparing the pixel areas of bone regions segmented from single-band images

This paper was concerned with the detection of hazardous bone fragments embedded in lean pork slices (LPS-BFs) by comparing the pixel area of bone regions segmented from single-band image. All images were collected using a Videometer A/S multispectral imaging system with 19 bands (405–970 nm). An area library of bone regions was established by processing 60 images captured from LPS-BFs and the minimum value of the library was defined as a boundary point for judgement. The accuracy of 90 % for 120 test samples (60 LPSs and 60 LPS-BFs) was achieved and all results could be visualized for monitoring the geometrical morphology of bones. Results of satisfactory identification of bone fragments embedded in LPSs indicated that image features at single-band could serve as a feasible approach for online industrial applications.

Classification of Beef and Pork Images Based on Color Features and Pseudo Nearest Neighbor Rule

This research is motivated by the need for halal foods in Muslim society with the purpose of avoiding non-halal foods, such as pork, that are sold in the market. Although beef and pork basically have different characteristics, not all Muslims know the differences. Moreover, people nowadays sell beef mixed with pork to obtain more profits. Hence, this paper proposed the implementation of the Pseudo-Nearest Neighbor Rule (PNNR) in classifying images of beef and pork slices based on color features. Based on the image dataset that has been collected, the very significant difference that can be identified visually between beef and pork is the color. The color features were extracted from the image using a color histogram from two different color channels, RGB and HSV. As the result, PNNR that used color features from the RGB channel achieved up to 87.43% accuracy, while using the HSV channel, it can reach up to 93.78% of accuracy. Additionally, this paper evaluates the stability of the proposed method by assessing the variance of classification accuracy across different values of k. It is also noticed that PNNR’s performance is relatively consistent for various values of k compared to the traditional kNN algorithm.

Potential Application of Ovalbumin Gel Nanoparticles Loaded with Carvacrol in the Preservation of Fresh Pork.

Plant essential oil has attracted much attention in delaying pork spoilage due to its safety, but its low antibacterial efficiency needs to be solved by encapsulation. Our previous research had fabricated a type of ovalbumin gel nanoparticles loaded with carvacrol (OCGn-2) using the gel-embedding method, which had a high encapsulation rate and antibacterial activity. The main purpose of this study was to further evaluate the stability and slow-release characteristics of OCGn-2 and potential quality effects of the nanoparticles on the preservation of fresh pork pieces during 4 °C storage. The particle test showed that the nanoparticles had better heat stability below 85 °C and salt stability below 90 mM. The in vitro release study indicated that the carvacrol in OCGn-2 followed a Fickian release mechanism. The pork preservation test suggested that the OCGn-2 coating treatments could remarkably restrict the quality decay of pork slices compared to free carvacrol or a physical mixture of ovalbumin and carvacrol treatment. Nano-encapsulation of ovalbumin is beneficial to the sustained release, enhanced oxidation resistance, and improved antibacterial activity of carvacrol. The study suggested that ovalbumin gel nanoparticles embedded with carvacrol could be applied as an efficient bacterial active packaging to extend the storage life of pork.

Effect of microwave drying on the brittleness quality of pork chip snacks: Perspectives on drying kinetics and microstructural traits

Ready-to-eat pork-based snacks have gained widespread popularity among consumers. The aim of this study was to investigate the brittleness quality of pork chip snacks (PCS) produced by microwave drying (MD) from the perspective of drying kinetics and microstructural traits. Changing microwave intensity and slice thickness significantly affected the colour and texture quality of the final PCS. The MD process of PCS presented a long heating-up phase and a short hindered drying phase, and the model of Midilli et al. described the drying kinetics well. The hindered drying phase dominated the ripening process and the formation of brittleness quality of PCS, and the temperature above 157.3 °C may cause an undesirable colour appearance. The microstructural characteristics showed that the formation of many large pores in PCS promoted the brittleness quality, while excessive temperature caused the tissue to melt with fewer pores to reduce brittleness. Overall, for fresh pork slices, it is recommended to produce PCS with a thickness of 3.5 mm at 4 W/g for 22 min to achieve a desirable brittleness quality. This study may provide a reference for the production of meat snacks such as PCS.

Comparison of efficiency between liquefied petroleum gas (LPG) and electric hot air dryer: case study of dried pork slice

ABSTRACT To reduce the foods spoilage in remote areas of Thailand where electricity is inaccessible, drying processes must be applied. This research developed an LPG hot air dryer under insufficient electricity supply and investigated its performance on dried pork slice under different air velocities (1, 1.5 and 2 m/s) and temperatures (50, 55 and 60°C). The results were compared with those of an electric hot air dryer, under the same conditions, to determine the optimal device. The drying rate from both dryers increased with an increase in temperature and air velocity. This mostly fitted with Avhad and Marchetti model. However, the lowest specific energy consumption was found in LPG hot air dryer. The moisture in dried pork slices was lower than 30%, regardless of different dryers. This agreed with Thai community product standard. Therefore, the LPG hot air dryer could be used as an alternative instrument for drying pork slice.

Sterilizing Ready-to-Eat Poached Spicy Pork Slices Using a New Device: Combined Radio Frequency Energy and Superheated Water.

In this study, a new device was used to inactivate G. stearothermophilus spores in ready-to-eat (RTE) poached spicy pork slices (PSPS) applying radio frequency (RF) energy (27.12 MHz, 6 kW) and superheated water (SW) simultaneously. The cold spot in the PSPS sample was determined. The effects of electrode gap and SW temperature on heating rate, spore inactivation, physiochemical properties (water loss, texture, and oxidation), sensory properties, and SEM of samples were investigated. The cold spot lies in the geometric center of the soup. The heating rate increased with increasing electrode gap and hit a peak under 190 mm. Radio frequency combined superheated water (RFSW) sterilization greatly decreased the come-up time (CUT) compared with SW sterilization, and a 5 log reduction in G. stearothermophilus spores was achieved. RFSW sterilization under 170 mm electrode gap reduced the water loss, thermal damage of texture, oxidation, and tissues and cells of the sample, and kept a better sensory evaluation. RFSW sterilization has great potential in solid or semisolid food processing engineering.

Application of a Newly Developed Chitosan/Oleic Acid Edible Coating for Extending Shelf-Life of Fresh Pork.

This study aimed at evaluating the applicability of a newly-developed chitosan/oleic acid edible coating for extending the shelf-life of fresh pork under aerobic-packaging conditions. Various coating formulations were used: 2% chitosan alone (CHI), 0.5% (v/v) oleic acid in 2% chitosan (CHI/0.5%OA) and 1% (v/v) oleic acid in 2% chitosan (CHI/1%OA) were prepared. For coating, fresh pork slices were fully immersed in the coating solutions for 30 s and dried naturally at 4 °C for 30 min. The coated samples were placed on trays, over-wrapped with plastic film, stored at 4 °C for 21 days, and were analyzed for shelf-life stability. Samples without coating were used as control. It was found that the aerobic bacteria and Pseudomonas spp. counts, and total volatile basic nitrogen (TVBN) content were almost two to three times lower in the CHI/OA-coated samples compared to the control after 21 days of storage (p < 0.05). The CHI/OA coating combination completely inhibited growth of E. coli, and protected the meat from discoloration after 21 days of storage. In particular, the addition of OA increased the concentration of volatiles associated with pleasant aromas. This study provides an application potential of chitosan/oleic acid edible coating in preservation of fresh pork to prolong the shelf-life and improve safety.

Analysis of Correlations between Quality Characteristics of Wheat Flour and Edible Quality of Crusts from Deep-fried and Battered Pork Slices

Analysis of Correlations between Quality Characteristics of Wheat Flour and Edible Quality of Crusts from Deep-fried and Battered Pork Slices

Salmonella spp. Response to Lytic Bacteriophage and Lactic Acid on Marinated and Tenderized Raw Pork Loins.

Bacterial food poisoning cases due to Salmonella have been linked with a variety of pork products. This study evaluated the effects of a Salmonella-specific lytic bacteriophage and lactic acid (LA) on Salmonella Enteritidis, Salmonella Montevideo, and Salmonella Heidelberg growth on raw pork loins. Pork loins were cut into approximately 4 cm thick slices. Pork slices were randomly assigned to five treatment groups (control, DI water, LA 2.5%, phage 5%, and LA 2.5% + phage 5%) with six slices per group per replication. Pork loins were inoculated with 106 CFU/mL of Salmonella spp. and stored at 4 °C for 30 min. After 1 h of treatment application and marination, phage 5% significantly (p < 0.05) reduced the surface bacterial population by 2.30 logs when compared with the control group. Moreover, the combined treatment of LA 2.5% + phage 5% significantly (p < 0.05) reduced the surface bacterial population by more than 2.36 logs after 1 h of marination. In the post-tenderization surface samples, the combination of both phage and LA showed a significant reduction (p < 0.05) when compared with the control group. However, the treatments had no effect (p > 0.05) when analyzing the translocation of pathogens on pork loins.

Effect of gelatin nano-coating containing Gardenia pigment on the preservation of pork slices.

The nano-coating composed of gelatin and Gardenia pigment (GP) was successfully prepared and showed strong antioxidant activity. The average particle sizes of the nano-coating containing 0.1% and 0.3% GP were 269.58 and 394.13nm, respectively. The pork slices uncoated and coated with the nano-coating were preserved at 4°C for 15days. The pork slices' pH, total volatile basic nitrogen (TVB-N), total viable counts (TVC), water-binding capacity (WHC), and thiobarbituric acid reactive substances (TBARS) were measured to assess the preservation effect of the nano-coating. The results showed that the pork coated with the nano-coating had lower pH, TVC, TVB-N, TBARS, and higher WHC, significantly different (p < 0.05) than the uncoated pork. It is suggested that the proposed nano-coating can be used to effectively improve the pork's quality and shelf life during refrigeration storage.

Effect of tannic acid-grafted chitosan coating on the quality of fresh pork slices during cold storage

Tannic acid (TA)-chitosan (CH) conjugate (TA-g-CH) was prepared using a free radical grafting procedure to increase the antimicrobial and antioxidant performance of CH. The effect of TA-g-CH coating on the quality of fresh pork during 15 days of refrigerated storage was investigated. The pork samples were analyzed regularly for microbiological (total viable counts (TVC), Pseudomonas spp. and lactic acid bacteria (LAB)), physicochemical (pH, thiobarbituric acid-reactive substances (TBARS), protein oxidation and color) and sensory attributes. The results showed that both TA + CH and TA-g-CH coatings dramatically extended the shelf-life of pork slices by suppressing microbial proliferation and delaying lipid and protein oxidation. Specifically, the TA-g-CH coating exhibited the best performance on pork preservation, which can delay the quality deterioration of fresh meat by 3–6 days during cold storage. The study suggests that the TA-g-CH edible coating has considerable prospects for maintaining the storage quality of fresh meat.

Application of Gelatin Composite Coating in Pork Quality Preservation during Storage and Mechanism of Gelatin Composite Coating on Pork Flavor.

Gelatin coating is an effective way to prolong the shelf life of meat products. Aiming at solving the problem of flavor deterioration during the storage of pork at room temperature, pork coating technology was developed to preserve the pork at 25 °C, and the comprehensive sensory analysis of vision, touch, smell, and taste was used to study the effect of coating on preservation of pork flavor. Herein, uncoated (control) and coated pork samples (including gelatin coating and gelatin coating incorporated with ginger essential oil) were analyzed to investigate the integrity of pork periodically during storage at 25 °C for weight loss, color, texture (springiness, chewiness, cohesiveness, gumminess, and hardness), microstructure, odor (electronic nose), taste (electronic tongue), volatile flavor substance, and taste ingredients. The results suggested that ginger essential oil (GEO) gelatin coating and gelatin coating can effectively inhibit the loss of water dispersion and slow down the oxidation reaction, coating treatments could significantly (p < 0.05) retarded the weight loss of pork slices, with values of 20.19%, 15.95%, 13.12% for uncoated, gelatin coated, and GEO-gelatin coated samples during 24 h of storage, respectively. Compared with control group, the color, texture, smell, and taste evaluations demonstrated that coating treatments had improved sensory and texture attributes during the storage period. Furthermore, the comprehensive results from the physical property assays (especially the texture), morphological assay and volatile odor assays showed that the GEO-fish gelatin composite coating had better preservation effect on pork flavor than the fish gelatin coating. The study suggests that the gelatin composite coating could be developed as a prospective active packaging to preserve pork meat at room temperature.

CRISPR-Cas system meets DNA barcoding: Development of a universal nucleic acid test for food authentication

Food authenticity is a critical issue owing economic or ethnic considerations. Herein, we introduce CRISPR-Cas system to food authentication via detecting DNA barcodes of livestock and poultry in both unprocessed and processed food samples, allowing for a specific molecular traceability of meat species. We integrated the specific sequence recognition of CRISPR/Cas12 system and the efficient amplification of PCR method to identify DNA barcodes to improve the accuracy of pork component identification. This method, termed CRISPR-Cas-based PCR DNA barcoding method (CAPCOD), can detect pork contamination diluted into 0.1% (w/w) in raw meat mixture, which ranks one of the most sensitive assays for food authenticity. And it has been applied to identify pork contents in complex processed halal food including beef luncheon meat, spiced beef and non-halal food including sausage, dried pork slices, pork balls and ham sausage. CRISPR-Cas-based DNA barcoding method is promising to serve as sensitive and reliable analytical tools for food authenticity.

Analysis of Dynamic Changes of Lipid Composition and Structure of Deep‐Fried Pork Slices during Storage

AbstractTo understand the reasons for the quality deterioration of traditional battered and deep‐fried pork slices during storage, fried pork slices stored for 12 h at 0–40 °C are used as the research samples, and Fourier‐transform infrared spectroscopy （FTIR） and gas chromatography‐mass spectrometry （GC‐MS） are used as analytical methods. The oil migration mode, fatty acid composition change, and functional group changes in the meat slices are analyzed. The experimental results show that the unsaturated fatty acid (USFA) in the starch paste enters the meat slice in a single diffusion mode during storage, and the migration direction of the fatty acid is reversed after 7 h. Oxidation mainly occurs after 4 h of storage. At this time, the absorption peak intensities of the C═C, OH, CH2, and CH3 groups began to increase significantly. After 8 h, the characteristic peak of C═O narrowed and disappeared after 12 h, indicating that the oxidation has entered a decline period. The content of USFA and linoleic acid (C18:2) showed a downward trend in phospholipids. Therefore, the stability of phospholipids, especially linoleic acid, plays an important role in the edibility of meat slices during storage.Practical Applications: Many studies have demonstrated that the edible quality of fried meat products decreases gradually during storage and the change in lipid content is the main reason for this phenomenon. However, there is a lack of targeted studies on lipid migration and compositional and structural changes during the storage of deep‐fried foods. In this study, dynamic mobility, dynamic modeling, and changes in fatty acid composition and structure of lipids before and after storage provide data support for the implementation of targeted improvement measures to reduce oil migration, oxidation, and decomposition, and thus effectively extend the consumption cycle.

Antimicrobial and antioxidant effects of edible nanoemulsion coating based on chitosan and Schizonepeta tenuifolia essential oil in fresh pork

The objectives of this study were to develop a nanoemulsion-based edible coating containing chitosan (CH) and Schizonepeta tenuifolia essential oil (STEO) and to investigate its coating effect on quality and shelf life of fresh pork stored at 4 ± 1°C for 16 days. Nanoemulsions with the average droplet sizes of 55.0–92.3 nm were prepared by subjecting coarse emulsions containing CH and STEO at 0.5%, 1%, and 2% (v/v) to ultrasonic emulsification. Zeta potential and polydispersity index of the prepared CH-STEO nanoemulsion were 45.5–57.3 mV and 0.17–0.28, respectively. The incorporation of 2% STEO into CH was applied as the coating formulation for pork slices. The coating treatments significantly prolonged the shelf-life of fresh pork by inhibiting microbial growth and retarding lipid oxidation. In particular, the CH-STEO nanoemulsion coating showed the best performance on meat preservation, which could be attributed to its smaller particle size with enhanced preservative function and stability. The study suggested that the active nanoemulsion loaded biopolymer edible coating has great potential for fresh meat preservation. Novelty impact statement This work investigates the effect of nanoemulsion-based edible coating containing chitosan (CH) and Schizonepeta tenuifolia essential oil (STEO) on quality and shelf life of fresh pork stored at 4 ± 1°C for 16 days. The results indicated that nanoemulsification was an effective approach to improve the physicochemical and bioactive properties of CH-STEO coating solution. Application of CH-STEO nanoemulsion (2% EO) coating in fresh pork significantly inhibited microbial growth and lipid oxidation during refrigerated storage.

CRISPR-Cas12-Based Rapid Authentication of Halal Food.

The halal food market is globally growing along with the increased risk of adulteration. We proposed an amplification-free and mix-to-read CRISPR-Cas12-based nucleic acid analytical strategy allowing rapid identification and analysis of pork components, thus enriching the toolbox for ensuring halal food authenticity. We designed and optimized guide RNA (gRNA) targeting the pork cytochrome b (Cyt b) gene. gRNA allowed specific identification of the target Cyt b gene from pork components followed by activation of Cas12 protein to abundantly cleave single-stranded DNA probes with terminally labeled fluorophore and quencher groups, thus turning on fluorescence. The presence of the pork Cyt b gene thus can be mix-and-read- and only-one-step-detected, which may indicate the risk of halal food adulteration. The method allowed specific discrimination of pork meat from beef, mutton, and chicken and yielded a detection limit of 2.7 ng/μL of total DNA from pork meat. The reliability of the method was tested using the following processed meat products: halal foods beef luncheon meat and spiced beef and non-halal foods sausage and dried pork slices. The CRISPR-Cas12-based nucleic acid test strategy is promising for rapid food authentication.

Multiwell Raman plate reader for high-throughput biochemical screening

Although Raman spectroscopy has been used for the quantitative analysis of samples in many fields, including material science, biomedical, and pharmaceutical research, its low sensitivity hindered the application of the analytical capability for high-throughput screening. Here, we developed a high-throughput Raman screening system that can analyze hundreds of specimens in a multiwell plate simultaneously. Multiple high numerical aperture (NA) lenses are assembled under each well in the multiwell plate to detect Raman scattering simultaneously with high sensitivity. The Raman spectrum of 192 samples loaded on a standard 384-well plate can be analyzed simultaneously. With the developed system, the throughput of Raman measurement was significantly improved (about 100 times) compared to conventional Raman instruments based on a single-point measurement. By using the developed system, we demonstrated high-throughput Raman screening to investigate drug polymorphism and identify a small-molecule binding site in a protein. Furthermore, the same system was used to demonstrate high-speed chemical mapping of a centimeter-sized pork slice.

PCR based method for authentication of pork in raw and processed products as well as in binary meat mixtures

In this study, amplification of species-specific marker of mitochondrial DNA origin was carried out to detect pork in raw, processed and meat mixtures containing varying concentrations of pork, viz. 1, 10, 50, 75 and 100%. The species-specific marker for pork was tested in raw pork from different breeds/varieties of pig such as Hampshire, Yorkshire, Ghungroo, Duroc, Rani, and Asha. The size of the amplified product was 290 bp in all the breeds/ varieties. The results were consistent in processed pork products, viz. frankfurter sausage, salami, cocktail sausage, pork slice, ham, and pork curry which were subjected to different cooking temperatures ranging from 75 to 121°C. In case of all the mixtures with different concentrations of pork, similar results were observed. Subsequently, this marker was tested for cross-amplification by checking them with beef, carabeef, mutton, chevon, chicken, and duck meat and no amplification was observed. The results suggested that the DNA marker used in this study is highly species-specific and reliable to detect pork adulteration, unambiguously, in raw, processed as well as in meat mixtures containing pork. This technique is rapid, simple and economical as compared to other methods of pork adulteration detection.