Characteristic Metabolic Changes of the Crust from Dry-Aged Beef Using 2D NMR Spectroscopy.

Two-dimensional quantitative nuclear magnetic resonance (2D qNMR)-based metabolomics was performed to understand characteristic metabolic profiles in different aging regimes (crust from dry-aged beef, inner edible flesh of dry-aged beef, and wet-aged beef striploin) over 4 weeks. Samples were extracted using 0.6 M perchlorate to acquire polar metabolites. Partial least squares-discriminant analysis showed a good cumulative explained variation (R2 = 0.967) and predictive ability (Q2 = 0.935). Metabolites of crust and aged beef (dry- and wet-aged beef) were separated in the first week and showed a completely different aspect in the second week via NMR-based multivariable analyses. Moreover, NMR-based multivariable analyses could be used to distinguish the method, degree, and doneness of beef aging. Among them, the crust showed more unique metabolic changes that accelerated proteolysis (total free amino acids and biogenic amines) and inosine 5'-monophosphate depletion than dry-aged beef and generated specific microbial catabolites (3-indoxyl sulfate) and γ-aminobutyric acid (GABA), while asparagine, glutamine, tryptophan, and glucose in the crust were maintained or decreased. Compared to the crust, dry-aged beef showed similar patterns of biogenic amines, as well as bioactive compounds and GABA, without a decrease in free amino acids and glucose. Based on these results, the crust allows the inner dry-aged beef to be aged similarly to wet-aged beef without microbial effects. Thus, 2D qNMR-based metabolomic techniques could provide complementary information about biochemical factors for beef aging.

Subacute feeding toxicity of low-sodium sausages manufactured with sodium substitutes and biopolymer-encapsulated saltwort (Salicornia herbacea) in a mouse model.

BACKGROUND: Low-sodium sausages were manufactured using sodium substitution and biopolymer encapsulation. A diet comprising 10% treatment sausages (six treatment groups: C (100% NaCl), T1 (55% sodium substitute + 45% saltwort salt), T2 (55% sodium substitute + 45% saltwort salt with chitosan), T3 (55% sodium substitute + 45% saltwort salt with cellulose), T4 (55% sodium substitute + 45% saltwort salt with dextrin), and T5 (55% sodium substitute + 45% saltwort salt with pectin)) was added to a 90% commercial mouse diet for 4 weeks. RESULTS: Subacute toxicity, hematology, liver function, and organ weight tests in low-sodium sausage groups showed results similar to those of the control group, and all toxicity test levels were within normal ranges. CONCLUSIONS: All low-sodium sausage types tested are suggested to be safe in terms of subacute toxicity. Moreover, low-sodium sausages can be manufactured by biopolymer encapsulation of saltwort using pectin, chitosan, cellulose, and dextrin without toxicity. © 2019 Society of Chemical Industry.

Impact of partial substitution of NaCl by KCl, and MgCl2 on physicochemical and sensory properties of cooked sausages during storage.

OBJECTIVE: To determine the effect of three salting treatments (Control: 100% NaCl, T1: 60% NaCl, and 40% KCl, T2: 50% NaCl, 40% KCl, and 10% MgCl2) on meat quality of sausages during storage. METHODS: Various types of curing salts were used for processing of salamis. Physico-chemical and sensory evaluation of the sausages were analyzed during 4 weeks of ripening. RESULTS: The pH values and salinity contents were the highest in control, while they were the lowest in T2 at 4 weeks (p<0.05). Control and T1 had less thiobarbituric acid reactive substances (TBARS) than T2 at 2 weeks (p<0.05). The volatile basic nitrogen (VBN) levels in T1 were similar to control and lower than T2 at 2 and 4 weeks (p<0.05). Moreover, T1 samples were redder and had a higher saturation index (C*) value when compared to the others. T2 showed greater hardness, gumminess and chewiness when compared with the control (p<0.05). Control was comparable to T1 for sensory attributes. CONCLUSION: sodium chloride may be partially substituted with potassium chloride without negatively influencing meat quality of sausages up to 4 weeks of storage. These results could help to develop low-sodium sausages.

Effects on quality properties of cooked pork sausages with Caesalpinia sappan L. extract during cold storage.

This study was evaluated the possibility of replacing some chemical additives in meat products by the Caesalpinia sappan L. (CS) extract. Four different types of cooked pork sausages were prepared by mixing nitrite with CS extracts at different concentration like control (without nitrite and extract), T1 (0.007% nitrite), T2 (0.004% nitrite + 0.05% extract) and T3 (0.1% extract). Physicochemical properties, sensory attributes, and antioxidant activity of the control and treatments were investigated. Ash contents and DPPH radical scavenging activity were significantly (P < 0.05) higher when pork sausages were processed with the addition of CS extracts. The rate of lipid oxidation significantly (P < 0.05) decreased in the case of CS extracts addition. By comparing with the control, all nitrite or CS extract resulted in significant (P < 0.05) lower L* values; however, 0.007% nitrite and 0.004% nitrite plus 0.05% CS extract pointed significantly (P < 0.05) higher a* values in all storage times. As well as, arrangement of CS extracts (0.05%) and nitrite (0.004%) in pork sausages displayed high gumminess and cohesiveness values (P < 0.05), stable springiness and chewiness, and significantly (P < 0.05) enhance overall acceptability scores as sensory attributes compared to the control sausage after 30 days of storage. Therefore, the CS extract (0.05%), which can act as a natural antioxidant, exert a positive effect with nitrite (0.004%) on the sensory acceptability and help to preserve the desired color of cooked pork sausages by reducing oxidation rate during cold storage.

Use of alternative curing salts for processing salamis.

OBJECTIVE: This study was performed to determine effects of different curing salts on the quality of salamis and to assess feasibility of using NaCl-alternative salts. METHODS: Various types of curing salts (KCl or MgCl2) as well as NaCl (sun-dried or refined) were incorporated for processing of salamis. The proximate composition, fatty acids, nucleotide-related compounds, and free amino acids of the salamis were analyzed during 40 days of ripening. RESULTS: The substitution of NaCl by KCl caused higher fat and ash content, but lower moisture content of the salami after 20 days of ripening (p<0.05). Compared with the sun-dried NaCl, use of KCl in salami also led to greater inosine 5'-monophosphate whereas refined NaCl had more inosine (p<0.05). KCl-added salami also had a higher C12:0, C17:1, and C20:0 than other types of salami (p<0.05). MgCl2-added salami had higher content of free amino acids compared to the other salamis (p<0.05). CONCLUSION: Alternative curing salts such as KCl and MgCl2 could substitute NaCl in consideration of quality factor of a fermented meat product. Especially replacement of NaCl with KCl will be a suitable strategy for developing relatively low sodium salami products without compromising product quality.

Quality Characteristics of Dry-cured Ham Made from Two Different Three-way Crossbred Pigs.

This study was conducted to compare the physicochemical traits of dry-cured hams made from two different three-way crossbred pigs: Yorkshire×Landrace×Duroc (YLD) and Yorkshire×Berkshire×Duroc (YBD). Animals were slaughtered at a live weight of 110 to 120 kg and cooled at 0°C for 24 h in a chilling room, the ham portion of the carcasses were cut and processed by dry-curing for physico-chemical analyses. While the moisture and crude protein contents of dry-cured ham were higher in YLD than in YBD, crude fat and ash content were higher in YBD (p<0.05). The salt contents of ham from YBD were higher than those from YLD (p<0.05). YBD ham samples showed a higher L* and b* values than those from YLD, while YBD ham showed lower a* value (p<0.05). Thiobarbituric acid reactive substances (TBARS) and volatile basic nitrogen (VBN) values of YLD hams were lower than those of YBD samples (p<0.05). Hardness, gumminess, chewiness, and shear force values of YBD ham were higher than those of YLD sample (p<0.05). Saltiness was significantly higher in YBD ham than in YLD samples (p<0.05). YLD ham displayed a superior quality than YBD. Considering the meat quality parameters of two-way crossbred ham, YLD hams could be more suitable for the production of dry-cured products.

Effect of Fat Level and the Ripening Time on Quality Traits of Fermented Sausages.

The objective of this study was to investigate the effect of the fat reduction on the physicochemical and microbiological characteristics of fermented sausages during ripening and drying. Low fat fermented sausages were produced with different fat levels (30%, 20%, 10%, and 5%) under ripening conditions and fermented process. Samples from each treatment were taken for physicochemical and microbiological analyses on the 0, 1, 2, 3, 4, 5, 7, 10, 14, and 21st day of ripening. In proximate analysis, the fat reduction in sausages produced an increase in moisture, protein and ash contents during ripening and drying (p<0.05). The weight losses were significantly higher in high fat formulations during the first 4 days, whereas those were higher in low fat ones after 10 days of storage (p<0.05). Fat reduction was responsible for an increase in shear force values after 3 days of storage. The volatile basic nitrogen (VBN) value of the low fat samples was significantly higher (p<0.05). Low fat sausages reduced the extent of lipid oxidation. The lower fat level produced redder sausages. Total plate bacteria and Pseudomonas counts of sausages showed no significant differences. Production of low fat sausages resulted in the physicochemical and microbiological attributes equal to or better than the high fat sausages without negative effects, except only a higher VBN and weight loss.

Quality Characteristics and Composition of the Longissimus Muscle from Entire and Castrate Elk in Korea.

The objective of the research was to determine the chemical composition as well as the physicochemical properties of the longissimus muscle from Korean entire and castrate elk. Twelve elk stags were raised and fed on concentrate with ad libitum hay. All animals were equally divided into castrated and non-castrated (entire) males, and slaughtered at 5 year of age. It was found that entire elk, in comparison with castrate elk, had higher content of moisture and lower content of fat (p<0.05). Compared with entire males, the castrates had lower pH and shear force values (p<0.05). However, castrates had higher L*, a*, and b* values compared with entires (p<0.05). An analysis of the fatty acid profile revealed that the muscles of entire and castrate elk had the most abundant concentrations of the following fatty acids: palmitic acid (C16:0) of the saturated fatty acid, and oleic acid (C18:1n-9) of the unsaturated fatty acid. The entire elk contains higher proportions of linoleic acid (C18:3n6), eicosenoic acid (C20:1n9), and arachidonic acid (C20:4n6) (p<0.05). Cholesterol content in elk was not affected by castration. The predominant free amino acid was glutamic acid related to umami taste. It is apparent that the castrate animals carried higher content of histidine, isoleucine, and leucine than those of the entire group (p<0.05). In this study, it was concluded that venison quality of elk is affected by castration and these results can provide fundamental information for venison production.

Monitoring the formation of cholesterol oxidation products in model systems using response surface methodology.

BACKGROUND: Cholesterol oxidation products (COPs) are produced during thermal processing of animal origin foods and are considered to have negative health impacts. The model systems are helpful to understand the impact of various factors on oxidation changes in foods during cooking process. METHODS: The study presented herein investigates the effects of pH, presence of unsaturated fatty acids, and heat on the formation of cholesterol oxidation products (COPs). Two model systems were designed to investigate the formation of cholesterol oxidation products in different lipid environments. The cholesterol oxides produced were quantified using gas chromatography. RESULTS: The level of cholesterol oxidation products decreased significantly at higher pH (above 5.8) and shorter heating time (3 h). The presence of unsaturated fatty acids (linoleic and oleic acids) significantly increased the amount of COPs under low-temperature heating conditions (100 °C and 1 h) but did not affect the production of COPs at higher temperature (150 °C). Increasing the temperature to 200 °C significantly increased the amount of COPs during the first hour of heating and this amount decreased upon further heating. The most frequently observed COPs in samples were α-epoxide, 20α-hydroxycholesterol, and 25-hydroxycholesterol. CONCLUSIONS: In conclusion, pH below 5.8, presence of unsaturated fatty acid, and high cooking temperature (>150 °C) leads to increased production of cholesterol oxidation products.

Cooking, storage, and reheating effect on the formation of cholesterol oxidation products in processed meat products.

BACKGROUND: Cholesterol is an important biological compound; however, its oxidation products have been proven to be harmful to human health. Cooking, storage, and reheating methods significantly affect the safety of meat products, as they contribute to the production of cholesterol oxidation products (COPs). METHODS: Three cooking methods were used to cook sausages, loin ham, bacon, luncheon meat, and pressed ham, in order to investigate the effect of cooking, storage, and reheating on total cholesterol and on the formation of COPs. Cooked samples were stored at 4 °C and reheated after 3 and 6 storage days by the same cooking method or by microwaving. The samples were assessed for total lipids, cholesterol, and cholesterol oxides. RESULTS: The average cholesterol content in the processed meat varied from 76.0 mg/100 g to 201.70 mg/100 g. Microwaved ham showed the lowest cholesterol content compared to that of other processed meat products. Significant differences were found in cholesterol content and cholesterol oxidation products depending on cooking, storage, and reheating methods. Six cholesterol oxides were found in processed meat, of which 7ß-hydroxycholesterol and α-epoxides were detected as the major oxidation products. CONCLUSIONS: Microwaving and oven grilling resulted in higher production of COPs in processed meat as compared with other cooking methods. Refrigerated storage tended to significantly increase the COPs content.

Impact of livestock industry on climate change: Case Study in South Korea - A review.

In recent years, there has been a growing argument attributing the primary cause of global climate change to livestock industry, which has led to the perception that the livestock industry is synonymous with greenhouse gas (GHG) emissions. However, a closer examination of the global GHG emission by sector reveals that the energy sector is responsible for the majority, accounting for 76.2% of the total, while agriculture contributes 11.9%. According to data from the Food and Agriculture Organization of the United Nations (FAO), the total GHG emissions associate with the livestock supply chain amount to 14.5%. Within this, emissions from direct sources, such as enteric fermentation and livestock manure treatment, which are not part of the front and rear industries, represent only 7%. Although it is true that the increase in meat consumption driven by global population growth and rising incomes, has contributed to higher methane (CH4) emissions resulting from enteric fermentation in ruminant animals, categorizing the livestock industry as the primary source of GHG emissions oversimplifies a complex issue and disregards objective data. Therefore, it may be a misleading to solely focus on the livestock sector without addressing the significant emissions from the energy sector, which is the largest contributor to GHG emissions. The top priority should be the objective and accurate measurement of GHG emissions, followed by the development and implementation of suitable reduction policies for each industrial sector with significant GHG emissions contributions.

Antioxidant Activity of Extracts of Balloon Flower Root (Platycodon grandiflorum), Japanese Apricot (Prunus mume), and Grape (Vitis vinifera) and Their Effects on Beef Jerky Quality.

This research examines the total polyphenol and flavonoid content and antioxidant activity of natural ingredients such as balloon flower root extract (BFE), Japanese apricot extract (JAE) and grape extract (GE). In addition, their effect on beef jerky quality characteristics was investigated when the extracts were used as alternatives to potassium sorbate (PS) and vitamin E (VE). BFE had higher (p < 0.05) total flavonoid content (TFC) (6.85 mg CAT eq/g), total polyphenol content (TPC) (10.52 mg RUT eq/g), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical (62.96%), and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging activity (87.60%) compared to other extracts. Although all extracts showed lower activity than BHT in all antioxidant activity tests, the BFE and JAE showed higher (p < 0.05) activity than the GE in the DPPH and FRAP assays. In contrast, in the ABTS assay, both BFE and GE showed increased activity (p < 0.05) compared to JAE. The jerky was prepared by adding 0.05% (v/v) each of BFE, JAE and GE. Furthermore, a control sample of jerky was also prepared by adding 0.10% (w/v) PS and 0.05% VE, respectively. On day 30, the redness (a*) values of the BFE and PS samples were also found to be significantly higher than those of the other samples (p < 0.05). Additionally, the yellowness (b*) values of the BFE sample were also found to be significantly higher than those of the other samples (p < 0.05). The thiobarbituric acid reactive substances (TBARSs) on day 30 were lower in the jerky treated with PS, VE, and GE compared to those treated with BFE and JAE (p < 0.05). In the sensory analysis, beef jerky with BFE had significantly higher overall acceptability scores on days 1 and 30 (p < 0.05). The addition of BFE to beef jerky influenced the increase in a* and b* values on day 30. The addition of GE effectively suppressed lipid oxidation to a level comparable to that of the PS and VE at day 30. Furthermore, the addition of BFE enhanced the overall acceptability of sensory characteristics.

Evaluation of the physicochemical, metabolomic, and sensory characteristics of Chikso and Hanwoo beef during wet aging.

OBJECTIVE: This study aimed to evaluate the physicochemical, metabolomic, and sensory qualities of Chikso and Hanwoo beef during 28 days of wet aging. METHODS: Rump and loins from Hanwoo and Chikso were obtained and wet-aged for 28 days at 4°C. The samples were collected at 7-day interval (n = 3 for each period). Physicochemical qualities including pH, meat color, shear force value, and myofibrillar fragmentation index, metabolomic profiles, and sensory attributes (volatile organic compounds and relative taste intensities) were measured. RESULTS: Chikso showed a significantly higher shear force value than Hanwoo on day 0; however, no differences between breeds were found after day 14, regardless of the cuts. Overall, Chikso had more abundant metabolites than Hanwoo, especially L-carnitine and tyrosine. Among the volatiles, the ketone ratio was higher in the Chikso rump than the Hanwoo rump; however, Chikso had fewer alcohols and aldehydes than Hanwoo. Chikso rump showed higher taste intensities than the Hanwoo rump on day 0, and sourness decreased in Chikso, but increased in the Hanwoo rump on day 14. Wet aging for 14 days intensified the taste of Chikso loin but reduced the umami intensity of Hanwoo loin. CONCLUSION: Chikso had different metabolomic and sensory characteristics compared to Hanwoo cattle, and 14 days of wet aging could improve its tenderness and flavor traits.

Mechanism of improving quality of dry-aged pork loins in scoria-containing onggi, Korean earthenware as a storage container.

OBJECTIVE: Many scientists have investigated solutions to reduce microbiological risks in dry-aged meat after the dry-aging technology was revived for high quality and value-added premium meat product in the market. This study aimed to investigate the effect of scoria powder in onggi (Korean earthenware) on the meat quality of pork loins during 21 days of dry aging and to elucidate its mechanism of action. METHODS: The pork loins were randomly divided into three groups: aged in vacuum-packaging, onggi containing red clay only (OR), and onggi containing 30% red clay and 70% scoria powder (OS). Microbial analyses (total plate count and Lactobacillus spp.) and physicochemical analyses (pH, shear force, volatile basic nitrogen [VBN], water activity, 2-thiobarbituric acid reactive substances, water content, water holding capacity, cooking loss, and color analysis) of aged meat were conducted. Far-infrared ray emission, quantification of immobilized L. sakei and microstructure of onggi were investigated to understand the mechanism. RESULTS: On day 21, the meat aged in OS exhibited lower pH, shear force, VBN, and water activity than those aged in OR, along with an increase in the number of Lactobacillus spp. OS had a smaller pore diameter than OR, implying lower gas permeability, which could promote the growth of L. sakei. CONCLUSION: OS improved the microbiological safety and storage stability of pork loin during dry aging by increasing number of Lactobacillus spp. possibly due to low permeability of OS.

Bactericidal Effect of Combination of Atmospheric Pressure Plasma and Nisin on Meat Products Inoculated with Escherichia coli O157:H7.

This study was conducted to investigate the bactericidal effect of nisin (Nisin) only, atmospheric pressure plasma (APP) only, and a combination of APP and nisin (APP+Nisin) on beef jerky and sliced ham inoculated with Escherichia coli O157:H7, gram-negative bacteria. The bactericidal effect against E. coli O157:H7 and Listeria monocytogenes was confirmed using a nisin solution at a concentration of 0-100 ppm, and APP+Nisin was tested on beef jerky and sliced ham using 100 ppm nisin. Beef jerky and sliced ham were treated with APP for 5 min and 9 min, respectively. In the bacterial solution, 100 ppm nisin out of 0-100 ppm nisin exhibited the highest bactericidal activity against L. monocytogenes (gram-positive bacteria; p<0.05); however, it did not exhibit bactericidal effects against E. coli O157:H7 (gram-negative bacteria). The APP+Nisin exhibited a 100% reduction rate in both E. coli O157:H7 and L. monocytogenes compared to the control group, and was more effective than the Nisin. The APP+Nisin decreased the number of colonies formed by 0.80 and 1.96 Log CFU/g for beef jerky and sliced ham, respectively, compared to the control, and exhibited a higher bactericidal effect compared to the Nisin (p<0.05). These results demonstrate the synergistic bactericidal effect of APP and nisin, providing a possible method to improve the limitations of nisin against gram-negative bacteria. In addition, this technology has the potential to be applied to various meats and meat products to control surface microorganisms.

Quality Evaluation of Mackerel Fillets Stored under Different Conditions by Hyperspectral Imaging Analysis.

This study was designed to compare the quality changes in mackerel fillets stored under different conditions by using hyperspectral imaging (HSI) techniques. Fillets packaged in vacuum were stored for six days under five different conditions: refrigerated at 4°C (R group); iced at 5±3°C (I group); kept at an ambient of 17±2°C (A group); frozen at -18°C for 24 h and thawed in a refrigerator at 4°C for 5 h on the sampling day (FTR group); FTR thawed in tap water instead of thawing in a refrigerator (FTW group). The FTR group had the lowest total bacterial count, drip loss, 2-thiobarbituric acid reactive substances, volatile basic nitrogen, and texture profile analysis values among groups during the entire storage period (p<0.05). Scanning electron microscopy revealed that the FTR group had less damage, while the other groups had shrunken muscle tissues. HSI integrated with the partial least squares model yielded reliable and efficient results, with high R2cv values, for several quality parameters of the mackerel fillets. Overall, the FTR group, involving freezing and thawing in a refrigerator, appears to be the most favorable option for maintaining the quality of mackerel fillets, which could be practically implemented in the industry. HSI is a suitable and effective technique for determining the quality of mackerel fillets stored under different conditions.

Influences of Aging Methods and Temperature on Meat Quality of Pork Belly from Purebred Berkshire and Crossbred Landrace×Yorkshire×Duroc (LYD) Pigs.

We studied effects of aging methods and temperature on the physical, chemical, and amino acid composition of pork belly from Berkshire and Landrace× Yorkshire×Duroc (LYD) swine. Pork belly samples were assigned randomly to breed groups (Berkshire and LYD), aging temperature groups (0°C and 9°C), and aging method groups. One samples of vacuum-packaged hanging pork bellies were hung in a refrigerated cooler with 83±2.0% humidity, while the other samples were immersed in a 3.5% salt solution in a vacuum package and subsequently stored in the same cooler for 2 weeks. LYD pork had lower pH and purge loss and higher lightness values than those of Berkshire pork (p<0.05). Moreover, thiobarbituric acid reactive substances and hardness values of LYD pork were lower than those of Berkshire pork after aging (p<0.05). Berkshire pork had a higher level of flavorful amino acids than LYD pork did during aging (p<0.05). Bellies aged at elevated temperatures for two weeks had higher volatile basic nitrogen. However, significantly higher percentages of flavorful and sweet taste amino acids were observed in bellies aged at 9°C compared to those aged at 0°C for 2 weeks. Moisture content was higher in immersed samples than hanging samples after two weeks of aging (p<0.05). Hanging pork bellies exhibited higher texture profiles than immersed pork bellies at two weeks (p<0.05). We concluded that breeds, aging temperature, and methods affected most quality attributes of pork belly.

Effect of cutting time and cooking temperature on physicochemical properties of chicken breast meat emulsion sausage with olive oil.

This study aimed to optimize the emulsification of olive oil in chicken sausage production at varying cutting times (30, 45, and 60 s) and cooking temperatures (63, 73, and 83°C). Pork backfat sausages were prepared as controls, using the same variables. The quality attributes of the sausages were analyzed, and the distribution of lipid droplets was identified using confocal laser scanning microscopy. The combinations of cutting time and cooking temperature in olive oil sausages showed different emulsifying characteristics. Meat emulsion with olive oil at a cutting time of 60 s and cooking temperature of 73°C showed the highest emulsion stability with lowest water and lipid loss (2.49%, P < 0.05). The pH values were lower for olive oil samples than for the controls (5.9 vs. 6.2, P < 0.05). Cutting time of 60 s and cooking temperature of 73°C generated higher hardness, gumminess, and chewiness in olive oil sausages (P < 0.05). The replacement of pork backfat with olive oil resulted in a higher b*, C*, and h values, as well as lower lipid oxidation (P < 0.05). In addition, microstructural images exhibited a finer distribution of lipid droplets in olive oil sausages with a cutting time of 60 s. In conclusion, chicken sausage at a cooking temperature of 73°C and cutting time of 60 s was optimal for producing sausages with olive oil. Given the condition, the sausages produced from olive oil had better emulsion and oxidative stability than sausages produced from pork backfat.

Effect of Temperature Abuse on Quality and Metabolites of Frozen/Thawed Beef Loins.

The objective of this study was to examine the effect of temperature abuse prior to cold storage on changes in quality and metabolites of frozen/thawed beef loin. The aerobic packaged samples were assigned to three groups: refrigeration (4°C) (CR); freezing (-18°C for 6 d) and thawing (20±1°C for 1 d), followed by refrigeration (4°C) (FT); temperature abuse (20°C for 6 h) prior to freezing (-18°C for 6 d) and thawing (20±1°C for 1 d), followed by refrigeration (4°C) (AFT). FT and AFT resulted in higher volatile basic nitrogen (VBN) values than CR (p<0.05), and these values rapidly increased in the final 15 d. Cooking loss decreased significantly with an increase in the storage period (p<0.05). In addition, cooking loss was lower in the FT and AFT groups than in the CR owing to water loss after storage (p<0.05). A scanning electron microscope (SEM) revealed that frozen/thawed beef samples were influenced by temperature abuse in the structure of the fiber at 15 d. Metabolomic analysis showed differences among CR, FT, and AFT from partial least square discriminant analysis (PLS-DA) based on proton nuclear magnetic resonance (1H NMR) profiling. The treatments differed slightly, with higher FT than AFT values in several metabolites (phenylalanine, isoleucine, valine, betaine, and tyrosine). Overall, temperature abuse prior to freezing and during thawing of beef loin resulted in accelerated quality changes.

Determining the Optimal Cooking Time for Cooking Loss, Shear Force, and Off-Odor Reduction of Pork Large Intestines.

The objective of this study was to determine the optimal cooking time by considering the cooking loss, shear force, and off-odor reduction of pork large intestines. Commercial pork large intestines were purchased, quartered perpendicularly, and cooked in boiling water for 40, 120, 180, and 240 min. Cooking loss of the samples increased after 240 min of cooking (10.92, p<0.05) while shear force value was lower at 240 min (4.45) compared to that at other cooking times (p<0.001). The amount of major volatile organic compounds showed a decreasing trend with increasing cooking time. In particular, the amount of methyl pentanoate (17,528.71) and methyl isobutyrate (812.51), compounds with a relatively low odor threshold, decreased significantly after 120 min of cooking and no change was observed thereafter (p<0.05). In addition, the amount of 2-pentanol (3,785.65) and 1-propanol (622.26), possibly produced by lipid oxidation, significantly decreased at the same cooking time (p<0.001). In the principal component analysis, only the 40 min cooking time was significantly different from other cooking time by high amounts of 1-propanol, 2-pentanol, and methyl isobutyrate. In conclusion, in the present study, the optimal cooking time for pork large intestines was 120 min in terms of off-odor reduction, cooking loss, and shear force.