Traceback Investigation for Salmonella Contamination at Egg Processing Plants in South Korea: Prevalence,Antibiotic Resistance,and Epidemiological Tracing by Rep‐PCR Fingerprinting

We conducted a survey of Salmonella from 8 egg‐breaking plants and a farm to determine the prevalence and the source of the bacteria. The contents of 2400 shell eggs (20 eggs per pool), 75 pasteurized liquid egg products, and 120 unpasteurized liquid egg products from 8 egg‐breaking plants in South Korea were examined. In liquid egg samples, 4 Salmonella‐positive samples from 120 unpasteurized ones (3.3%) and 5 positive samples from 75 pasteurized ones (6.7%) were identified; no eggs were positive for Salmonella among shell egg samples. To trace the source of Salmonella, we revisited the 2 Salmonella‐positive plants (plants A and C). We investigated the equipment and environments of the plants and a henhouse (farm A) that supplied shell eggs to plant A, and collected additional liquid eggs and shell eggs from plants A and C. All Salmonella isolates from plant A and the associated farm A, except for a single Typhimurium strain from farm A, were serotyped as Bareilly. Three serovars, including one Bareilly, four Tennessee, and one Richmond, were isolated from plant C. Most Salmonella isolates were susceptible to tested antibiotics. To identify differences between isolates, molecular subtyping by using the automated rep‐PCR system was conducted. All Salmonella Bareilly (S. Bareilly) strains from plant A exhibited high similarity, indicating possible contamination by Salmonella strains from the henhouse A. Meanwhile, 2 S. Bareilly strains from plant C, one from liquid egg at the 1st visit and the other from container at the 2nd visit, exhibited identical antibiotic resistance and similar subtyping pattern, but clearly discriminated from the ones of plant A.     

Comparing effects of α‐ vs. β‐chitosan coating and emulsion coatings on egg quality during room temperature storage

Effects of α‐ and β‐chitosan (CH), soybean oil (SO) and their emulsions (CH:SO = 2:3) as coating materials on selected internal quality and sensory properties of eggs were evaluated during 5 weeks storage at 25 °C. After 3 weeks of storage, α‐ and β‐CH‐coated eggs changed to B grade, while SO‐ and emulsion‐coated eggs preserved grade A quality. Weight loss of eggs coated with SO and CH:SO emulsions was <2.0% vs. 5.3–5.8% for noncoated and CH‐coated eggs after 5 weeks of storage. β‐CH (0.9%) maintained lower weight loss of eggs than α‐CH (1.2%) only at 1‐week storage. Albumen pH of eggs coated with SO and CH:SO emulsions decreased progressively throughout storage. Eggs coated with β‐CH:SO emulsion and SO were significantly glossier than noncoated eggs. Consumers indicated positive purchase intent (69.17–76.67%) for all coated eggs. Overall, α‐CH:SO and β‐CH:SO emulsions extended egg shelf life by at least 3 weeks during room temperature storage.     

25—CROSS-BREEDING STUDIES WITH SELECTED FLEECE LINES OF SCOTTISH BLACKFACE SHEEP

This paper presents the results of an investigation of the fleeces of sheep that were the offspring of crosses (HF) between a hairy line (HH) of the Scottish Blackface breed that had been selected for 20 years for hairiness and a fine line (FF) that had been selected for fine fleeces. Other crosses investigated were between each of the selected lines and an unselected Control (CC) line (HC and FC), and with the Wensleydale breed (WH and WF).

The lines had been selectively bred on an index of wool-fibre medullation determined from an eight-week-lamb coat sample, and there was some evidence of heterosis in the index of HC lambs, the values being closer to the value in hairy lambs than the mid-parent value. Fibre-type array (FTA) determined at the same age showed that HC and HF animals were more hairy than Controls, while FC lambs had finer arrays.

The Wensleydale-cross lambs had considerably reduced hair coverage and lower hair densities than the Blackface, and FTAs showed a shift from the 100% Plateau arrays of the Blackface to either Saddle or Ravine in WH lambs, or Saddle to Plain in WF lambs. The lack of halo hairs indicated the elimination of kemp.

At birth, fibre medullation in the skin of WH lambs was 30% less than that in HH animals, and the proportion with a latticed medulla was reduced from 50 to 3%. Latticed medullation was also reduced in WF lambs, but in neither cross was the S/P follicle ratio significantly increased.

In the line crosses at six months, skin sections indicated follicle groups like those of the Controls in appearance. Follicle density showed no significant difference. At six months there was no difference in any follicle-density trait between any lines or crosses, and the only groups to show any difference in diameter traits were the HH and FF lines, since all the line crosses and the CC did not differ significantly.

With medulla traits, neither the diameter of the central primary fibres nor the width of their medullae varied among all lines and crosses, but the FF line had finer lateral primaries with a narrower medulla, and the line crosses had intermediate values, except in HC sheep, which had lateral primaries with a medulla that was not significantly narrower than in the HH animals, suggesting heterosis in hairiness. This is supported by the fact that HH, HC, and FH sheep had significantly more medullated secondary fibres than CC, FC, and FF animals. But, since this occurred in FH and not HF sheep, some maternal influence seems to be implicated in addition.

The Wensleydale crosses had no difference in any follicle-density trait from the pure lines, but they had finer primary fibres and coarser secondary fibres. In both crosses, the diameter of the central primaries and the width of the medulla were reduced, which indicated the elimination of kemp, but, with the lateral primaries, these were reduced in only the WH crosses.

The practical importance of these fundamental results lies (a) in the lack of evidence of a single dominant gene like that in the New Zealand Drysdale breed, which causes offspring of crosses to have a hairy fleece; (b) in the evidence of heterosis in medullation (hairiness), which means that crosses of hairy with fine animals are likely to be more hairy than the intermediate value; and (c) in the confirmation of the Wensleydale as a breed capable of eliminating kemp and reducing medullation. The findings explain the disappointing results from attempts to improve fleeces by crossing with the merino, since such crosses frequently retain kemp. The sequence to follow is first to cross with the Wensleydale to eliminate kemp and then to cross the Wensleydale crosses with the merino to make the wool finer.     

Effects of egg weight on egg quality characteristics

BACKGROUND: The experiment was carried out with total of 270 eggs, which were collected from a brown‐egg layer strain of Lohmann hens reared in a cage system. Collected eggs were categorized according to weight and classified as medium, large, extra‐large or jumbo. The purpose of the study was to determine the effect of egg weight on egg quality characteristics. RESULTS: The darkest shell color scales were noted in jumbo eggs. The redness of egg shell color in the medium egg was significantly lower than that of the other egg sizes (P < 0.05). Egg shell thickness (P < 0.05) was highest in medium egg (0.400 mm) and lowest in extra‐large egg (0.382 mm). Albumen height (AH) was significantly affected by egg weight (EW) (P < 0.01). Yolk height (YH) and yolk index (YI) increased with egg size. Breaking strength was highest in the medium‐weight egg. There were significant positive correlations between EW and AH, EW and YH, EW and YI, EW and yol color, EW and redness (a), but EW had significant negative correlations with ST in overall eggs. CONCLUSION: The darkest shell color (L‐a‐b) was noted in the jumbo egg. Albumen height and yolk height increased with egg weight. Increase in egg weight caused darkness in the yolk color scale. Copyright © 2008 Society of Chemical Industry     

Effect of Lactobacillus cultures on microbiological,chemical and odour changes during storage of rainbow trout fillets

The purpose of this study was to investigate the effect of applying two Lactobacillus protective cultures on microbiological, chemical and odour changes during storage of refrigerated vacuum‐packed rainbow trout (Oncorrynchus mykiss) fillets. Lactobacillus sakei CECT 4808 and Lb. curvatus CECT 904^T were inoculated individually or in combination into rainbow trout fillets. The samples were vacuum‐packed and stored at 4 ± 0.5 °C and were assessed during a 20‐day storage period for microbiological (Enterobacteriaceae, Pseudomonas spp., lactic acid bacteria (LAB), H₂S‐producing bacteria, yeasts and moulds) and chemical (pH, total volatile basic nitrogen, lipid oxidation) parameters and off‐odour. Samples inoculated with Lb. sakei and with both strains had significantly (P≤0.05) lower counts of all microbiological spoilage indicator organisms (Enterobacteriaceae, Pseudomonas spp., H₂S‐producing bacteria, yeasts and moulds) than those inoculated with Lb. curvatus or the controls. All chemical parameters examined and off‐odour scores were also significantly (P≤0.05) improved in the samples inoculated with Lb. sakei or with both strains compared with those inoculated with Lb. curvatus or the controls. Lb. sakei generally showed a better preservative effect (P≤0.05) than the combination of strains. Inoculation with Lb. sakei CECT 4808 could provide an additional hurdle to improve shelf‐life of refrigerated vacuum‐packaged trout fillets, as inoculation with this strain resulted in extension of shelf‐life by 5 days. Furthermore, this strain showed some antioxidative ability, which could retard lipid oxidation in fish. Copyright © 2006 Society of Chemical Industry     

Inactivation of Salmonella in Shell Eggs by Hot Water Immersion and Its Effect on Quality

Thermal inactivation kinetics of heat resistant strains of Salmonella Enteritidis in shell eggs processed by hot water immersion were determined and the effects of the processing on egg quality were evaluated. Shell eggs were inoculated with a composite of heat resistant Salmonella Enteritidis (SE) strains PT8 C405, 2 (FSIS #OB030832), and 6 (FSIS #OB040159). Eggs were immersed in a circulating hot water bath for various times and temperatures. Come‐up time of the coldest location within the egg was 21 min. SE was reduced by 4.5 log at both hot water immersion treatments of 56.7 C for 60 min and 55.6 °C for 100 min. Decimal reduction times (D‐values) at 54.4, 55.6, and 56.7 °C were 51.8, 14.6, and 9.33 min, respectively. The z‐value was 3.07 °C. Following treatments that resulted in a 4.5 log reduction (56.7 °C/60 min and 55.6 °C/100 min), the surviving population of SE remained static during 4 wk of refrigerated storage. After processing under conditions resulting in 4.5 log reductions, the Haugh unit and albumen height significantly increased (P < 0.01) and yolk index significantly decreased (P < 0.05). The shell dynamic stiffness significantly increased (P < 0.05), while static compression shell strength showed no significant difference (P < 0.05). Vitelline membrane strength significantly increased (P < 0.05); although, no significant difference (P < 0.05) was observed in vitelline membrane elasticity. In summary, the hot water immersion process inactivated heat resistant SE in shell eggs by 4.5 log, but also significantly affected several egg quality characteristics.     

Influences of a natural colourant on colour and salty taste perception,liking, emotion and purchase intent: a case of mayonnaise‐based dipping sauces

Effects of colourant and a ‘natural source’ statement on sensory liking, emotion, saltiness expectation and purchase intent (PI) of three dipping sauces containing shrimp head colourant [no‐colourant (NC); moderate‐colourant (MC, 1.2% colourant); high‐colourant (HC, 3.6% colourant)] were evaluated. Consumers disliked colour of HC compared to MC (4.65 vs. 6.24). Despite the same NaCl level, saltiness liking decreased with increasing colourant [6.38 (NC), 5.43 (MC), 3.97 (HC)]. Correspondence analysis biplot revealed that sauces with or without natural colourant were associated more with positive emotions. Positive emotion (good, interested, satisfied) scores decreased while negative emotion worried increased with increasing colourant concentration. The ‘natural source’ statement decreased guilty and unsafe scores but minimally affected PI of NC and MC. Saltiness expectation was not different between NC (off‐white colour) vs. MC (lighter orange) and between NC vs. HC (darker orange); however, consumers expected HC to be saltier than MC.     

GELLING AND COLOR PROPERTIES OF OSTRICH (STRUTHIO CAMELUS) EGG WHITE

The effect of temperature upon the denaturation process of ostrich egg‐white protein was studied, and it compared with that of commercial hen eggs. Turbidity and color properties evolution were used to determine this effect. In addition, egg‐white gels (from both ostrich and hen egg whites) were obtained by heat treatment at 80C, and these were characterized by means of color, textural properties and water‐holding capacity (WHC). Results showed that although 55C was the temperature for the start of coagulation in both types of egg white, only in hen egg white was the process completed at 65C. The gels obtained at 80C (both ostrich and hen egg‐white gels) presented a strong structure that would allow ostrich egg white to be used as a gelling agent in the food industry as it happens with hen egg white.     

Effect of garlic powder on the performance,egg traits and blood parameters of laying hens

This study was conducted to investigate the effects of garlic powder on the performance, egg traits and blood parameters of laying hens. One hundred and sixty‐two SHSY‐type brown layers aged 21 weeks were chosen at random from a large flock. They were allocated to three dietary treatments. Each treatment comprised six replicates of nine layers in groups of three. The diets were supplemented with 0, 5 and 10 g kg^?1 garlic powder. The experimental period lasted 22 weeks. Garlic powder addition did not significantly affect body weight, egg production, feed consumption, feed efficiency, egg shell index, egg breaking strength, egg shell thickness, egg albumen index, egg yolk index, egg Haugh unit, egg yolk weight and serum protein concentration. Egg weight increased (P < 0.01) with garlic powder supplementation. There was a significant (P < 0.01) reduction in egg cholesterol concentration as mg g^?1 yolk when the dietary level of garlic powder was increased from 0 to 10 g kg^?1. Hen serum triglyceride (P < 0.05) and total cholesterol (P < 0.01) concentrations decreased with garlic powder supplementation. This study demonstrated that garlic powder addition increased egg weight and decreased egg yolk cholesterol concentration (mg g^?1 yolk) and serum triglyceride and cholesterol concentrations without adverse effects on performance and egg traits. Copyright © 2006 Society of Chemical Industry     

Antioxidant Properties of Aqueous Extract of Roasted Hulled Barley in Bulk Oil or Oil‐in‐Water Emulsion Matrix

Antioxidant properties of the aqueous extracts of hulled barley (Hordeum vulgare L.) that had been roasted at 210 °C for 20 min were determined in bulk oil and oil‐in‐water (O/W) emulsions. Bulk oils were heated at 60, 100, and 180 °C, and O/W emulsions were oxidized under riboflavin photosensitization. The content of phenolic compounds was analyzed by high‐performance liquid chromatography, and in vitro antioxidant assays were also conducted. The major phenolics contained in the aqueous extract of roasted hulled barley (AERB) were p‐coumaric, ferulic, protocatechuic, chlorogenic, 4‐hydroxybenzoic, and vanillic acids. Depending on the concentration and oxidation temperature, AERB had antioxidant or prooxidant properties in bulk oil. At 60 °C, AERB at a concentration of 0.5% acted as a prooxidant, whereas at 1.0% it acted as an antioxidant. At 100 °C, AERB acted as an antioxidant irrespective of concentration. In 180 °C conditions, 0.5% AERB acted as a prooxidant, whereas other concentrations of AERB acted as antioxidants. In the case of riboflavin photosensitized O/W emulsions, AERB showed antioxidant properties irrespective of concentration. Antioxidant abilities of AERB are affected by the food matrix, including bulk oil and O/W emulsions, and concentrations of AERB, even though diverse phenolic compounds may display high antioxidant properties in in vitro assays.     

Effects of Green Tea Extract and α‐Tocopherol on the Lipid Oxidation Rate of Omega‐3 Oils,Incorporated into Table Spreads,Prepared using Multiple Emulsion Technology

Abstract: This study examined the effectiveness of fat and water soluble antioxidants on the oxidative stability of omega (ω)‐3 rich table spreads, produced using novel multiple emulsion technology. Table spreads were produced by dispersing an oil‐in‐water (O/W) emulsion (500 g/kg 85 camelina/15 fish oil blend) in a hardstock/rapeseed oil blend, using sodium caseinate and polyglycerol polyricinoleate as emulsifiers. The O/W and oil‐in‐water‐in‐oil (O/W/O) emulsions contained either a water soluble antioxidant (green tea extract [GTE]), an oil soluble antioxidant (α‐Tocopherol), or both. Spreads containing α‐Tocopherol had the highest lipid hydroperoxide values, whereas spreads containing GTE had the lowest (P < 0.05), during storage at 5 °C, while p‐Anisidine values did not differ significantly. Particle size was generally unaffected by antioxidant type (P < 0.05). Double emulsion (O/W/O) structures were clearly seen in confocal images of the spreads. By the end of storage, none of the spreads had significantly different G′ values. Firmness (Newtons) of all spreads generally increased during storage (P < 0.05). Practical Application: Lipid oxidation is a major problem in omega‐3 rich oils, and can cause off‐odors and off‐flavors. Double emulsion technology was used to produce omega‐3 enriched spreads (O/W/O emulsions), wherein the omega‐3 oil was incorporated into the inner oil phase, to protect it from lipid oxidation. Antioxidants were added to further protect the spreads by reducing lipid oxidation. Spreads produced had good oxidative stability and possessed functional (omega‐3 addition) properties.     

Thermoultrasonication Eliminates Salmonellae from Intact Eggshells without Changing the Functional Properties of their Components

We have previously reported that the simultaneous application of heat and ultrasound (thermoultrasonication) to intact eggs allows a reduction in the number of Salmonella enterica serovar Enteritidis present on the shell to a safe hygienic level in less severe conditions (temperature and time) than those usually recommended for common pasteurization. In the present work, the effect of thermoultrasonication on selected functional properties of egg compounds (shelf‐life, emulsifying and foaming capacities, emulsion and foam stabilities, texture properties of egg white gel, breakage resistance of shell, and sensory properties of cooked egg) has been studied under the conditions previously defined (54 °C for 5 min) for the developed treatment. No significant differences were obtained in any of properties assayed between thermoultrasonicated and untreated (fresh) eggs. We concluded that it is possible to pasteurize the surface of intact eggs by applying a thermoultrasonic treatment yielding a product with a safe level of S. Enteritidis and cause negligible damage to the thermolabile egg components.     

Effect of muscle type and cooking temperature on liver‐like off‐flavour of five beef chuck muscles

Steaks (1.9 cm thick) from the US Department of Agriculture (USDA) Select grade beef chuck muscles (Infraspinatus, Longissimus dorsi, Serratus ventralis, Supraspinatus and Terres major) were cooked to two temperatures commonly applied in US restaurants (71 °C and 82 °C) and evaluated for liver‐like off‐flavour by trained panel. Pigment content of raw muscles were determined to establish its effect on liver‐like off‐flavour. Mean myoglobin content of Serratus (9.26 mg g^?1) was significantly lower than other beef chuck muscles analysed in this study. Infraspinatus had highest (P < 0.05) mean liver flavour of 2.08 where other muscles had <2. Rancid flavour was slightly but significantly increased from 1.34 to 1.58 as internal cook temperature increased from 71 °C to 82 °C; however mean thiobarbituric acid (TBA) values were not affected by cooking temperature. Infraspinatus had small but significant incidence of liver‐like off‐flavour. Cooking temperature had a clear impact on rancidity as evaluated by trained panel but no direct impact on liver‐like off flavour was observed.     

Emulsifying Properties of Low-fat, Low-cholesterol Egg Yolk Prepared by Supercritical CO2 Extraction

Comparisons were made with native egg yolk, dried egg yolk and a commercial yolk substitute (soy lecithin). Aqueous emulsions were prepared by sonicating water containing 0–5% NaCl, 20% peanut oil, HC1 or NaOH as needed for pH adjustment, and 1–3% emulsifier expressed as the total of phospholipids, glycolipids and proteins contributed by yolk ingredients or soy lecithin. The median diameters of fat particles in the emulsions with and without dispersing fat droplet floes using Triton X-100, were evaluated by laser light diffraction. The emulsifying properties of low-fat, low-cholesterol egg yolk were similar to or better than those of native yolk and dried egg yolk. Soy lecithin had less effective emulsifying properties than yolk ingredients with respect to coalescence of fat droplets during storage and separation during 70°C treatment.     

The effect of short term storage on the albumen quality of shell eggs

Certain physical changes occur naturally in the albumen of shell eggs when stored under cool conditions which cause the thick white to become thin. The whipping characteristics of the albumen are changed during this process but the functional performance of the albumen as measured by the angel food cake method is not affected to any marked degree. Three 10-day storage trials were undertaken using day-old shell eggs which demonstrated that a significant loss of albumen performance did not occur until the storage temperature reached 18 ºC. This conclusion clearly indicates the importance of maintaining shell eggs under cool conditions between collection at the farm and commercial distribution by the egg floors, particularly during the summer season.     

Influence of rapid chilling on biochemical parameters governing the water‐holding capacity of pork longissimus dorsi

The aim of this study was to investigate the effects of rapid chilling (RC) of carcasses on the quality of pork longissimus dorsi (LD) compared to conventional chilling (CC). Carcasses subjected to RC were chilled at ?20 °C for 1.5 h and then moved to 4 °C until 24 h post‐mortem, while carcasses that were CC were placed directly in a chill at 4 °C for 24 h post‐mortem. RC accelerated the rates of temperature decline post‐mortem (P < 0.01) and increased pH values at 1.5 and 8 h post‐mortem (P < 0.05). RC could significantly decrease the denaturation of myosin and sarcoplasmic proteins during post‐mortem ageing. Samples of RC had a significant lower purge loss compared to CC group during post‐mortem ageing (P < 0.05). Our study implies that RC could influence the biochemical changes of pork LD which may further regulate water‐holding capacity during post‐mortem ageing.     

An integrated strategy to control post-harvest decay of Embul banana by combining essential oils with modified atmosphere packaging

Mature Embul (Musa, AAB) bananas were treated with emulsions of either cinnamon bark or leaf (Cinnamomum zeylanicum) or clove (Syzygium aromaticum) oils to control post‐harvest diseases, packed under modified atmosphere (MA) using low‐density polyethylene (0.075 mm, LDPE) bags, and stored in a cold room (14 ± 1 °C, 90% RH) or at ambient temperature (28 ± 2 °C). The effects of the essential oils on post‐harvest diseases; physico‐chemical properties and organoleptic properties were determined and compared with controls and bananas treated with benomyl. Treatments with cinnamon bark and leaf oils controlled crown rot, whereas clove oil treatment did not affect crown rot development. Treatment with emulsions of cinnamon oils combined with MA packaging can be recommended as a safe, cost‐effective method for extending the storage life of Embul bananas up to 21 days in a cold room and 14 days at 28 ± 2 °C without affecting the organoleptic and physico‐chemical properties.     

Cross‐linking of bovine and caprine caseins by microbial transglutaminase and their use as microencapsulating agents for n‐3 fatty acids

Bovine and caprine caseins were cross‐linked with microbial transglutaminase (mTG). The mTG‐cross‐linked bovine or caprine casein dispersion, mixed with 14.5% maltodextrin (DE = 40), was used to prepare emulsions with 10.5% algae oil. Oxidative stability of emulsions was evaluated by peroxide values (PVs) and anisidine values. Adding liposoluble rosemary extract rich in carnosic acid and δ‐tocopherol lowered the formation of hydroperoxides and their subsequent decomposition products in emulsions. Emulsions stabilised with liposoluble rosemary extract rich in carnosic acid and δ‐tocopherol were spray‐dried at 180/95 °C. Algae oil microencapsulated with mTG‐cross‐linked bovine casein reduced PV by ≈ 34%, while the algae oil microencapsulated with mTG‐cross‐linked caprine casein with low levels of α_s1‐casein reduced PV by ≈ 42% at 4 weeks of storage at 30 °C. The investigation suggests that liposoluble rosemary extract rich in carnosic acid and δ‐tocopherol effectively protected algae oil during the coating process with mTG‐cross‐linked bovine and caprine caseins. The above results clearly indicated that the choice of milk caseins (bovine vs. caprine) cross‐linked with mTG impacts the oxidative stability of spray‐dried algae oil emulsions (microcapsules) enriched with n‐3 fatty acids.     

The influence of seasonal temperatures on meat quality characteristics of hot-boned, m. psoas major and minor, from goats and sheep

Samples of psoas major and minor muscles were randomly collected weekly from 203 (99 hot and 104 cool seasons) Omani goats, 215 (106 hot and 109 cool seasons) Omani sheep, 212 (104 hot and 108 cool seasons) Somali goats, 242 (127 hot and 115 cool seasons) Somali sheep and 211 (110 hot and 101 cool seasons) Australian Merino sheep slaughtered at the Central Slaughterhouse in Oman to investigate the effect of season on meat quality. The collection period was during November 2004–October 2005 and divided into two seasons according to ambient temperatures and relative humidity. These were termed: cool season (average temperature of 21 °C and 59% relative humidity and hot season (average temperature of 35 °C and 47% relative humidity). Muscles collected during the hot season had significantly (P < 0.05) higher ultimate pH values (5.78) than those collected during the cool season (5.65). Myofibrillar fragmentation index was significantly (P < 0.05) higher for hot season samples (86.88%) than for cool season samples (85.59%). Expressed juice was significantly (P < 0.05) higher for cool season samples (36.84) than for hot season samples (35.74). Goat meat from the hot seasonal group was significantly (P < 0.05) darker than the cold season group based on L* (37.6 vs. 39.6), a* (20.0 vs. 23.3) and b* (3.6 vs. 4.2) colour measurements. These results indicated that high ambient temperatures had caused an increase in muscle ultimate pH leading to significant effects on meat quality.     

Thermal behavior of concentrated oil-in-water emulsions based on soybean oil and palm kernel olein blends

Droplet size distribution and thermal behavior of concentrated oil-in-water emulsions based on soybean oil (SBO)/palm kernel olein (PKO) blends were investigated. The emulsions were prepared using 70% (wt./wt.) oil blends of SBO/PKO as dispersed phases and stabilized by egg yolk. An increase in PKO level (0–40% wt./wt.) in the oil dispersed phase volume fraction caused significant increases (p < 0.05) in volume-weighted mean diameter (d_4,3). The DSC data suggested that crystallization of the emulsions was induced by a ‘template effect’ of yolk constituents via a surface heterogeneous nucleation. Emulsions with 0–20% (wt./wt.) PKO levels in the dispersed phase demonstrated a good cool–heat stability even after three successive thermal cycles (from 50 °C to ?70 °C at 10 min/°C). After the first thermal cycle, emulsions with 30% and 40% PKO levels in the oil dispersed phase were destabilized due to strong coalescence and crystallized via volume-surface heterogeneous nucleation. The unstable emulsions were attributable to high level of saturated triacylglycerols from PKO, with high droplet size characteristic, causing them to be more prone to partial coalescence.