Antioxidant, Collagenase Inhibitory, and Antibacterial Effects of Bioactive Peptides Derived from Enzymatic Hydrolysate of Ulva australis.

The protein extract of Ulva australis hydrolyzed with Alcalase and Flavourzyme was found to have multi-functional properties, including total antioxidant capacity (TAC), collagenase inhibitory, and antibacterial activities. The #5 fraction (SP5) and #7 fraction (SP7) of U. australis hydrolysate from cation-exchange chromatography displayed significantly high TAC, collagenase inhibitory, and antibacterial effects against Propionibacterium acnes, and only the Q3 fraction from anion-exchange chromatography displayed high multi-functional activities. Eight of 42 peptides identified by MALDI-TOF/MS and Q-TOF/MS/MS were selected from the results for screening with molecular docking on target proteins and were then synthesized. Thr-Gly-Thr-Trp (TGTW) displayed ABTS [2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)] radical scavenging activity. The effect of TAC as Trolox equivalence was dependent on the concentration of TGTW. Asn-Arg-Asp-Tyr (NRDY) and Arg-Asp-Arg-Phe (RDRF) exhibited collagenase inhibitory activity, which increased according to the increase in concentration, and their IC50 values were 0.95 mM and 0.84 mM, respectively. Peptides RDRF and His-Ala-Val-Tyr (HAVY) displayed anti-P. Acnes effects, with IC50 values of 8.57 mM and 13.23 mM, respectively. These results suggest that the U. australis hydrolysate could be a resource for the application of effective nutraceuticals and cosmetics.

Effects of nitrite-rich and pigment-rich substitutes for sodium nitrite on the quality characteristics of emulsion-type pork sausages during cold storage.

This study was conducted to evaluate the effects of nitrite-rich (celery powder; CP) and pigment-rich (purple sweet potato powder, PSP; red beet powder, RB) substitutes for synthetic sodium nitrite (CON) on the quality characteristics of emulsion-type pork sausages during four weeks of cold storage. Natural substitutes decreased the pH, lightness, and textural properties of pork sausages during storage (P < 0.05). Pigment-rich substitutes showed a decreased antioxidant effect after two weeks of storage when compared to the nitrite-rich groups (CON and CP; P < 0.05). Pigment-rich substitutes also accelerated the discoloration of pork sausages by increasing yellowness (RB and PSP) and decreasing redness (PSP) during storage (P < 0.05). However, these two pigment-rich substitutes showed different trends in redness (higher in PSP and lower in RB) and yellowness (higher in RB and lower in PSP) when compared to the nitrite-rich groups (CON and CP). Different types (nitrite-rich and pigment-rich) of natural substitutes for sodium nitrite had different effects on the quality characteristics of emulsion-type pork sausages throughout the four weeks of storage evaluated in this study.

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.

Effects of porcine blood plasma on the emulsion stability, physicochemical characteristics and textural attributes of emulsified pork batter.

This study was conducted to determine the effects of addition of porcine blood plasma (PBP) to the emulsified pork batter as a substitute for the soy protein isolate (SPI) or sodium caseinate (SC) on the emulsion stability and physicochemical and textural properties of the emulsified pork batter. A total of 10 treatments were no addition and 0.5%, 1.0%, and 1.5% addition with each of SPI, SC, and PBP. The moisture and fat losses of the pork emulsion after cooking decreased with increasing percentage of any of SPI, SC, and PBP (p < 0.05). Further, moisture loss was less for the PBP treatment than for SPI and SC (p < 0.05). The lightness, redness, and whiteness of the emulsified pork batter decreased (p < 0.05) due to any of the SPI, SC, and PBP treatments whereas the yellowness and the chroma and hue values increased. The lightness, redness, yellowness, and chroma and hue values differed also among the SPI, SC, and PBP treatments (p < 0.05); however, the numerical difference between any two types of substitutes was less than 8% of the two corresponding means in all of these variables. Textural properties, including the hardness, cohesiveness, springiness, gumminess, chewiness, and adhesiveness, were not influenced by any of the SPI, SC, and PBP treatments (p > 0.05), except for greater gumminess and chewiness for the PBP treatment than for SC. The present results indicate that PBP is comparable or even superior to SPI or SC in its emulsion-stabilizing effect and therefore could be used a substitute for the latter as a non-protein ingredient of pork emulsion batter.

The effect of boiled feed on trace elements of longissimus dorsi muscle in Hanwoo steers.

Boiled feed is obtained by mixing and boiling agricultural by-products such as rice straw, rice bran, and bean curd with grains. The study explored the change in fatty acid, free amino acid, nucleotide, mineral, cholesterol, myoglobin and collagen of longissimus dorsi muscle in Hanwoo steers fed with boiled feed. Forty steers, 20 heads per group, were divided into two groups: a control group and a boiled feed group. The steers were raised for 10 months. The boiled feed group was enriched with palmitoleic acid, oleic acid, arachidonic acid and unsaturated fatty acids compared with the control group. There were no significant differences in amino acid and nucleic acid composition between the two groups. The boiled feed group contained higher levels of iron and manganese in the boiled feed group compared with the control group. The total cholesterol level was significantly increased, whereas calorie levels, myoglobin and collagen composition showed no differences. As the supply of boiled feed increases the content of fatty acids, unsaturated fatty acids and minerals related to flavor, it should be a feed that leads to the production of high-quality beef.

Effect of porcine plasma hydrolysate on physicochemical, antioxidant, and antimicrobial properties of emulsion-type pork sausage during cold storage.

This study evaluated the effect of porcine plasma hydrolysates (PPH) on the physicochemical, antioxidant, and antimicrobial properties of emulsion-type pork sausages. Five levels of PPH were added to sausages (CON, 0 g/kg; T1, 5 g/kg; T2, 10 g/kg; T3, 15 g/kg; and T4, 20 g/kg) and their chemical composition, purge loss, lipid oxidation, microbial count, pH, color, texture, and sensory properties were compared on day 1 and after 4 weeks of cold storage. At 4 weeks of storage, hardness, cohesiveness, and gumminess were highest in T3 (P < 0.05). The peroxide value increased in all treatments during the 4-weeks of storage (P < 0.05); however, it was not significantly different between CON, T2, and T3 (P > 0.05). The total aerobic plate count was the lowest in T4 at week 4 (P < 0.05). Therefore, PPH addition could improve the texture of the emulsion-type pork sausages, and an antimicrobial effect was expected following exposure to at least 20 g/kg PPH.

Effects of partial substitution of nitrites with purple-fleshed sweet potato powder on physicochemical characteristics of sausages.

Synthetic nitrite imparts a reddish-pink color to meat and a distinct flavor to meat products, delays lipid oxidation, and inhibits microbial growth and pathogens. However, excessive intake of nitrite might result in the production of carcinogenic nitrosamine, which might increase the risk of cancer in humans. Therefore, we aimed to find an alternative natural colorant for pork sausages. Pork sausages were mixed with 0.014% sodium nitrite (NaNO2) alone (CON), without either NaNO2 or purple-fleshed sweet potato powder (PP; CON1), 0.5% PP alone (PP1), 1% PP (PP2) alone, 0.011% NaNO2 and 0.5% PP (SP1), and 0.011% NaNO2 and 1% PP (SP2). The sausages were then cooked and stored for physicochemical analysis on days 0, 5, 10, 15, and 20. The a* and W* values were the greatest and lowest in the SP2 and CON1 treatments, respectively (p < 0.05). The concentrations of residual nitrite in the sausages at 20 days decreased in the order of CON > SP1, SP2 > PP2 > PP1, CON1. The fatty acid content was higher, and flavorous amino acids were more in PP2 (p < 0.05). The fatty acid composition was comparable between the SP2 and CON groups, but the contents of glutamic acid and alanine were greater in the SP2 group. In conclusion, SP2 (0.011% NaNO2 with 1% PP) could be added as a natural colorant for pork sausage production, and NaNO2 could be substituted with up to 20% PP without detrimental effects on sausage appearance and/or quality.

Comparison of Effects of Two Aging Methods on the Physicochemical Traits of Pork Loin.

The objective of this study was to compare effects of two different aging methods on physical, chemical, and microbial traits of pork loin: Dry and wet-aged meat was hung in the cooler at 8±1°C and 85±2.1% humidity for 14 days, while wet-aged meat was immersed in a 3.5% salt solution of brine in vacuum pouches. On day 7, pH and moisture content were higher in dry-aged loins than in wet-aged, while drip loss and total plate counts (p<0.05) were lower on day 14. As aging continued, the pH and drip loss of dry-aged loins decreased, while their total plate counts and water holding capacity (WHC) increased (p<0.05). After 7 and 14 days of aging, redness in dry-aged loins was higher than that in wet -aged muscles (p<0.05). On day 14 of aging, hardness, chewiness, and adhesiveness were lower in dry-aged pork loin as compared to those in wet-aged samples (p<0.05). Consequently, the results suggested that dry and wet aging methods differently affects meat quality traits of pork loin.

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&amp;lt;0.05). Control and T1 had less thiobarbituric acid reactive substances (TBARS) than T2 at 2 weeks (p&amp;lt;0.05). The volatile basic nitrogen (VBN) levels in T1 were similar to control and lower than T2 at 2 and 4 weeks (p&amp;lt;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&amp;lt;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 of the plane of nutrition during the latter grower and entire finisher phases on grow-finish pig performance in summer.

The present study was undertaken to investigate the effects of the plane of nutrition (PN) for growing-finishing pigs on growth performance and meat quality in summer. One hundred and two barrows and 102 gilts weighing approximately 44 kg were placed on a high-, medium-, or low-plane grower diet (HPG, MPG, or LPG) with ME and lysine concentrations ranging from 3.33 to 3.40 Mcal/kg and 0.93% to 1.15%, respectively, for 29 days in 6 replicates (pens) in total. Pigs from each grower pen were divided into two finisher pens and provided with a high-plane finisher diet (HPF) containing 3.40 Mcal ME and 9.5 g lysine/kg and a low-plane finisher diet (LPF; 3.25 Mcal ME and 8 g lysine/kg), respectively, up to approximately 110 kg, and slaughtered. Growth performance of the pigs, including average daily gain (ADG), average daily feed intake (ADFI), and gain:feed ratio, was not influenced by the grower-phase PN during any of the grower phase, a 31-d finisher phase I, and ensuing phase II. However, both the ADG and gain:feed ratio were greater (p < 0.05) for the HPF group than for the LPF group during the finisher phase I (748 vs. 653 g with SEM = 13 g and 0.333 vs. 0.299 with SEM = 0.008, respectively). The ADG, but not gain:feed ratio, was greater for the HPF group vs. LPF during the finisher phase II (673 vs. 623 g with SEM = 15 g for ADG and 0.322 vs. 0.323 with SEM = 0.005 for the gain:feed ratio). The carcass backfat thickness (BFT) was greater for the LPF group vs. HPF within the pigs which had been placed on LPG during the grower phase, but not within the pigs from the HPG or MPG group. Physicochemical characteristics of the longissimus dorsi muscle (LM) and sensory quality attributes of fresh and cooked LM were not influenced by either the grower-phase or finisher-phase PN. In conclusion, high PN is necessary for finishing pigs during the hot season to minimize the reduced rate of weight gain and also to prevent the increase of BFT that could result from low PN.

Microbial changes under packaging conditions during transport and comparison between sampling methods of beef.

This study was performed to evaluate the microbial and temperature changes of boxed beef during transport and distribution under vacuum and modified atmosphere packaging (MAP), and to compare between excision and swab sampling for 15 days. The top round and striploin (quality grade 1) from Hanwoo steers at 2 days post-slaughter were obtained from a local meat processing plants and chilled at 4 ± 2°C in a cold room. The boxes were transported under refrigeration (4 ± 2°C) to the laboratory within half an hour. Vacuum and MAP packs were subsequently taken out from cool boxes, and microbiological examinations were carried out at 0, 6, 12, and 24 h of storage time. MAP was more effective than vacuum packaging for the inhibition of total aerobic, lactic acid bacteria and Pseudomonas (p < 0.05). Microbial loads of swab methods were slightly lower than those of excision ones (p < 0.05). The results of this study could be utilized by meat consumers in future studies as well as by manufacturers to determine the ideal storage conditions for cool boxed meat, thus ensuring reduced economic losses due to spoilage.

The Effects of Natural Antioxidants on Protein Oxidation, Lipid Oxidation, Color, and Sensory Attributes of Beef Patties during Cold Storage at 4℃.

This study aimed to investigate the use of golden thread extract (GTE), clove extract (CE), and commercially available nitrite for retarding lipid and protein oxidation and for maintaining color stability and sensory attributes in beef patties stored at 4℃. GTE, CE, and nitrite treatment samples were found to be efficient in retarding lipid oxidation as all three treatments resulted in low thiobarbituric acid reactive substance (TBARS) content (p<0.05). By using GTE, CE, and nitrite into beef patties, protein oxidation was not developed. Incorporation of GTE and CE into beef patties maintained color stability by protecting against the decrease of L*, a*, b*, chroma, and hue angle values and exhibited significant influence on sensory characteristics, including color and odor of beef patties (p<0.05). Compared to commercially available nitrite, GTE and CE were more effective as antioxidants for inhibiting lipid oxidation, and preserving color stability of fresh beef patties. The study indicated that GTE and CE could be utilized efficiently to extend the shelf life of beef patties.

Natural curing agents as nitrite alternatives and their effects on the physicochemical, microbiological properties and sensory evaluation of sausages during storage.

This study investigated the effects of different curing agents on the physicochemical properties, microbiological properties and sensory evaluation of sausages formulated with and without nitrite over 4 weeks of cold storage. Seven batches were prepared: control, sodium nitrite 0.01%; celery powder 0.8% (T1); fruit extract powder 0.6% (T2); purple sweet potato powder 0.45% (T3); fruit and vegetable extract powders 0.5% (T4); gardenia red 0.04% (T5); paprika and blueberry powder 0.07% (T6). T1 produced significantly lighter, redder and yellower sausages compared to control and had a higher color intensity (C*) and hue (h). The residual nitrite ion concentration was the highest in the control and declined most rapidly in control, T1, and T2 during storage. The pH, thiobarbituric acid reactive substances (TBARS), volatile basic nitrogen (VBN) content, and total microbe counts were the same for T1 and the control. T1 received comparable sensory attributes as the control. These results suggest that celery powder effectively protects sausages from quality deterioration during storage.

Effects of Bundle Type and Substitution with Spent Laying Hen Surimi on Quality Characteristics of Imitation Crabsticks.

The purpose of this study was to evaluate the effects of bundle type (BT) and substitution with spent laying hen (SH) surimi on quality characteristics of imitation crabsticks made from Alaska Pollack (AP) during 6 wk of cold storage. Diagonally bundled samples had poorer gel characteristics and more lipid oxidation when compared with straight bundled ones (p<0.05). The color of diagonally bundled imitation crabsticks deteriorated with storage time (p<0.01). However, BT did not affect sensory characteristics (p>0.05). SH substitution had an effect on most quality characteristics of imitation crabsticks; darker and poorer gel characteristics were observed and its effect on sensory evaluation was seen at the initial storage. Thus, BT and SH substitution can be considered to have a slight effect on eating quality of imitation crabsticks, despite their negative effects on color, gel characteristics, and lipid oxidation.

Effect of Gleditsia sinensis Lam. Extract on Physico-Chemical Properties of Emulsion-Type Pork Sausages.

This study was performed to investigate the effect of Gleditsia sinensis Lam. extract on the physicochemical properties of emulsion-type pork sausages during storage at 10°C for 4 wk. Treatments were as follows: (C, control; T1, sodium ascorbate 0.05%; T2, Gleditsia sinensis Lam. 0.05%; T3, Gleditsia sinensis Lam. 0.1%; T4, Gleditsia sinensis Lam. 0.2%; T5, Gleditsia sinensis Lam. 0.1% + sodium ascorbate 0.05%). The values of pH, moisture content, lightness, redness, and sensory attributes were all significantly decreased, while the yellowness, chroma, hue angle, and texture properties were increased during storage with increase of the Gleditsia sinensis Lam. extract added. In addition, the antioxidant activity and antimicrobial activity in the sausages displayed significant increases (p<0.05). Therefore, although it was concluded that the addition of Gleditsia sinensis Lam. extract is not effective for improvement of the physical properties compared to chemical additives in sausages, it could be applied to meat products as a natural preservatives.

Effect of Calcium Lactate on Physico-Chemical Characteristics of Shank Bone Extract.

This study was conducted to develop calcium-fortified shank bone extract (SBE) and to determine the effect of adding calcium lactate on physico-chemical characteristics of SBE during cold storage. The following five experiment groups were used: Control (0%, no addition), T1 (0.05% calcium lactate), T2 (0.1% calcium lactate), T3 (0.5% calcium lactate), and T4 (1% calcium lactate). When the concentration of calcium lactate added to the SBE was increased, the pH, redness, and yellowness values were significantly reduced, whereas the salinity, sugar content, and turbidity of SBE were significantly increased. Sensory parameters such as aroma, flavor, and overall acceptability in the control, T1, and T2 had similar scores. The TBARS values of SBE was significantly increased when 1% of calcium lactate was added, and the VBN values of SBE with calcium lactate at day 7 were higher than that of control (p<0.05). However, the addition of calcium lactate showed an inhibition effect on the growth of total microbial counts in SBE until 4 d of storage. The calcium content of SBE was increased by the addition of calcium lactate in a dose-dependently manner. The proper addition level of calcium lactate in the SBE was determined to be 0.1%.

Effects of the addition of blood plasma proteins on physico-chemical properties of emulsion-type pork sausage during cold storage.

BACKGROUND: Most slaughter blood is discarded, resulting in problems related to costs for wastewater disposal and environmental pollution. However, animal blood contains various proteins such as albumin, globulin and globin and can be used as a natural emulsifier, stabiliser and colour additive. Thus, this study was carried out to investigate the effect of blood plasma proteins on the physico-chemical properties of emulsion-type pork sausages stored at 4°C over 5 weeks. RESULTS: The emulsion-type pork sausages with plasma powders had higher pH than the other treatments during week 5, and higher shear force than the control (P < 0.05). The lightness values of the sausages with plasma powders were lower than the other treatments, whereas the redness and yellowness values were similar with those of the others. The sausages with plasma powders (cattle plasma powder and commercial pig plasma powder) had respectively increased texture properties. In the sensory evaluation, all proteins did not have significant impact on sensory of pork sausages. CONCLUSION: The results confirmed that plasma protein powders can be considered as a binder for the production of excellent meat products compared to other binders. © 2017 Society of Chemical Industry.

Comparison of Meat Quality and Fatty Acid Composition of Longissimus Muscles from Purebred Pigs and Three-way Crossbred LYD Pigs.

This study was conducted to find pork quality to meet the needs of consumers. Thus, the meat quality and fatty acid composition of longissimus muscles from purebred pigs (Landrace, Yorkshire, and Duroc) and three-way crossbred LYD pigs were compared and evaluated. Chemical compositions of longissimus muscles were significant (p<0.05) different among pigs. Duroc contained significant (p<0.05) higher fat contents than other pigs, whereas significant (p<0.05) higher moisture contents were observed in Landrace, Yorkshire, and LYD pigs compared to those of Duroc pigs. The values of pH24 h and pH14 d were the highest in Landrace pigs. Myoglobin contents of LYD pigs were higher (p<0.05) than those of purebred pigs. Regarding meat color, Duroc and Yorkshire pigs had higher redness values than Landrace and LYD pigs, while Landrace pigs had the lowest (p<0.05) color values among all pigs. There was no significant difference in shear force or water holding capacity (WHC). Duroc pigs maintained the lowest drip loss during 14 d of cold storage. In sensory evaluation, the marbling scores of Duroc pigs were higher (p<0.05) than other pigs. Regarding fatty acid compositions, total USFA, poly-, n-3, and n-6 contents were the highest (p<0.05) in LYD pigs, while total SFA contents were the highest (p<0.05) in Duroc pigs. Based on these results, purebred pigs had superior overall meat quality to crossbred pigs.

The effect of clove bud powder at a spice level on antioxidant and quality properties of emulsified pork sausage during cold storage.

BACKGROUND: Clove bud is a widely used spice in meat and meat products, and it contains high level of phenolic compounds. The effectiveness of the clove as a spice has not been fully studied at a general level of addition in the meat products. Therefore, in the present study, the antioxidant, antimicrobial, and nitrite scavenging abilities of clove bud powder (CBP) was assessed at spice level (0.1% and 0.2%) in emulsified pork sausage, during 6 weeks of cold storage. RESULTS: CBP had DPPH radical scavenging ability, but CBP addition at 0.1% and 0.2% did not decrease the TBARS value. An antimicrobial effect of CBP was also not observed during the cold storage. However, residual nitrite at storage weeks 4 and 6 was shown to be lower (P < 0.05). Addition of CBP decreased CIE L* and a* values, but it produced unacceptable sensory properties. Texture profile analysis was not affected by the addition of CBP in emulsified pork sausage (P > 0.05). CONCLUSIONS: The positive effect on nitrite scavenging could be expected by the addition of 0.2% CBP as a spice. However, antioxidant and antimicrobial abilities were not observed, as well as improvement in the quality of characteristics, in emulsified pork sausage. © 2016 Society of Chemical Industry.

Effect of the Ratio of Raw Material Components on the Physico-chemical Characteristics of Emulsion-type Pork Sausages.

This study was conducted to investigate the effects of raw material ratio on the physicochemical characteristics of emulsion-type pork sausages. Experiment design was divided into 12 treatments, based on protein level (P), fat level (3P, 3.5P, and 4P), and water level (4P+10, 4P+15, 4P+20, and 4P+25). The pH and shear force values were significantly higher in T7 (3.5P fat and 4P+20 water) than those of other treatments. The lightness and redness were greatly reduced by increasing the quantity of water. The treatments containing 3P fat and 4P+20 water had the highest values of cohesiveness, springiness, gumminess, and chewiness. On the whole, when the protein (P) and fat (3P, 3.5P, 4P) levels were fixed, an increase over the appropriate moisture level deteriorated many physicochemical characteristics.