The Impact of Premortality Stress on Some Quality Parameters of Roe Deer, Wild Boar, and Red Deer Meat.

The specifics of meat production from free-ranging animals include the killing of animals in the wild with firearms. This type of uncontrolled killing sometimes leads to the phenomenon that the game does not die immediately but after a certain time from the shot to death, which may ultimately affect the quality of the meat. During one hunting year on free-ranging red deer (Cervus elaphus) (RD), roe deer (Capreolus capreolus) (RoD), and wild boar (Sus scrofa) (WB), the effect of time from shot to death on final pH, water-holding capacity (WHC), water content, and colour (L*, a*, b*) was investigated. All analyses were performed on Musculus biceps femoris (BF). After shooting, the animals were divided into two categories (A = time from shot to death ≤ 1 min; B = time from shot to death > 1 min). In RD, group B had significantly lower (p < 0.05) water content. In RoD, group B had significantly lower (p < 0.05) values of L* and b*. In WB, group B had significantly lower (p < 0.05) L* value and significantly higher (p < 0.05) pH value. The study proves that in BF of the three studied game species, the time extension from shot to death significantly affects the final water content values in RD, L* and b* in RoD and pH and L * in WB.

Influence of Muscle Type on Physicochemical Parameters, Lipolysis, Proteolysis, and Volatile Compounds throughout the Processing of Smoked Dry-Cured Ham.

The influence of muscle type (biceps femoris, BF and semimembranosus, SM) on physicochemical parameters, volatile compounds, and the extent of proteolysis and lipolysis during the manufacturing of smoked dry-cured ham was investigated. A total of fifty smoked hams were sampled: raw ham, after salting, smoking, drying, and ripening. Almost all physicochemical parameters were affected by muscle type, manufacturing stage and their interactions. SM had lower water, ash, NaCl content, and water activity (aw), while fat and protein content were higher after ripening compared to BF. BF showed higher L*a*b* values compared to SM. The results of texture profile analysis showed that almost all analyzed parameters were influenced by muscle type and production stage. A total of 88 volatile compounds were identified, showing an increase in its number during processing: 31 volatile compounds were identified in raw ham and 72 after the ripening phase. Aldehydes and phenols were the predominant groups of compounds, followed by alcohols, ketones, aromatic hydrocarbons, aliphatic hydrocarbons, esters, and terpenes. Muscle type and production phase significantly affected lipid oxidation and the index of proteolysis: in SM, thiobarbituric acid reactive substances (TBARS) increased faster than in BF, while proteolysis had an opposite effect and was more pronounced in BF.

Proteolysis and protein oxidation throughout the smoked dry-cured ham process.

During the five stages of smoked dry-cured ham processing, proteolysis and protein oxidation were simultaneously detected in the Biceps femoris (BF) and Semimembranosus (SM) muscles. Proteolysis was more advanced in BF than in SM throughout the process of production. The total FAA increased significantly (p < 0.05) throughout the processing, resulting in higher total FAA content in BF than in SM muscle. SDS-PAGE revealed progressive degradation of sarcoplasmic proteins of investigated muscles, with the pronounced changes for the 69.9-41.7 kDa region. SDS-PAGE of BF showed more intense degradation of myofibrillar proteins due to greater proteolysis in BF. Electrophoresis of myofibrillar proteins evidenced the marked degradation of 130 kDa, 96.7 kDa and 27-20.7 kDa bands in both muscles. A similar trend was observed for protein oxidation in BF and SM, with the final values of 26.36 and 23.7 nmol carbonyls/mg proteins, respectively. The Pearson correlation revealed a strong relationship between protein oxidation and proteolysis.

Effect of citric acid addition on functional properties of pasteurized liquid whole eggs.

The aim of this study was to examine the influence of different concentrations of citric acid (0, 300, 400 and 500 mg/L) on the physical and functional properties of pasteurized liquid whole eggs (LWE) over 4 weeks of storage. The properties tested include pH, conductivity, colour, particle size, rheological, and textural properties, as well as protein solubility, foaming and emulsification. The 4 weeks of storage had a statistically significant (P < 0.05) effect on every tested parameter, while the addition of citric acid had a statistically significant (P < 0.05) effect on pH, conductivity, L* and b* values, protein solubility, emulsion activity index, emulsion capacity, emulsion stability, and an increase in foaming and texture parameters, but not on rheological parameters. Citric acid addition and a storage period of 4 weeks resulted in a change of pH and an increase in protein solubility. It also led to a lower foaming capacity and a larger drainage of the system, which causes a lower power (work load) requirement to break formed gels. Apparent viscosity did not change significantly in the samples with citric acid.

The impact of frozen storage duration on physical, chemical and microbiological properties of pork.

The aim of the present study was to evaluate the effect of frozen storage duration (3, 6, 9, 12, 15, 18 months) on physical, chemical and microbial properties of pork in three cuts (loin, ham, and belly rib). During frozen storage, significant alterations in physical and chemical parameters were observed through the increase of the total exudate, pH and lightness (L*), and a decrease of shear force and yellowness (b*). Water content in ham samples decreased, while protein content increased. The lipid oxidation (TBA) values in loin and ham samples increased for up to fifteen months of frozen storage, after which they decreased. The proportion of saturated fatty acids in frozen samples was significantly higher than in fresh meat. The total amount of Enterobacteriaceae, S. aureus and Pseudomonas spp. decreased during frozen storage, indicating that freezing may reduce the number of bacteria found in meat. Frozen pork microflora did not change after eighteen months of storage.

Differentiation of dry-cured hams from different processing methods by means of volatile compounds, physico-chemical and sensory analysis.

The aim of this study was to characterize dry-cured hams from four different processing methods (differences in primary leg treatment, salting and smoking phase). Volatile compounds were isolated by using headspace-solid phase microextraction and analysed by gas chromatography/mass spectrometry (GC/MS). Samples were also evaluated by sensory and physico-chemical characteristics (moisture, protein, fat and NaCl content, aw, colour). 149 volatile compounds of dry-cured hams were identified and 15 of them were quantified. Identified volatile compounds belonged to several classes of chemical: 25 aldehydes, 18 phenols, 12 alcohols, 16 terpenes, 27 aromatic hydrocarbons, 18 aliphatic hydrocarbons, 17 ketones, 9 esters and 7 acids. Most abundant volatiles in ham samples were aldehydes (34.46-49.78%). Principal component analysis showed a good separation among groups. Smoked dry-cured hams showed a higher content of phenols, aromatic hydrocarbons, and acids and were characterized by smoky aroma, while non-smoked dry-cured hams showed higher content of terpenes, ketones, alcohols, esters, aliphatic hydrocarbons and were characterized with spicy aroma.

Characterization of volatile compounds, physico-chemical and sensory characteristics of smoked dry-cured ham.

Volatile compounds from smoked dry-cured ham were isolated by using headspace-solid phase microextraction and gas chromatography-mass spectrometry (GC-MS). Samples of biceps femoris were also evaluated for sensory physical and chemical characteristics. Eighty seven volatile aroma compounds of smoked dry-cured ham were identified. Chemical groups identified were aldehydes (35.6%), phenols (34.3%), alcohols (13.8%), terpenes (6.4%), aromatic hydrocarbons (2.6%), alkanes (2.2%), ketones (2.2%), esters (1.7%) and acids (0.7%). Except volatile compounds derived from lipolysis and proteolysis the second most abundant constituents were phenols that originate from smoking phase of the production process. The most abundant phenols were: 4-methylphenol, 3-methylphenol, 2-metoxy-4-methylphenol, 2-methylphenol, 2,6-dimethoxyphenol and 4-ethyl-2 methoxyphenol. Principal components analysis showed that NaCl and ash content positively correlated with the salty taste while fat content was correlated to marbling. Water content and aw value were negatively correlated with hardness of dry-cured ham while phenols were positively corelated with smoky aroma. Due to the different volatile composition and pronounced smoky aroma, smoked dry-cured ham can be distinguished from other types of dry-cured hams.

Determination of volatile compounds and quality parameters of traditional Istrian dry-cured ham.

The aim of this work was to determine the characteristics of Istrian dry-cured ham by instrumental methods and sensory analysis. The aroma-active compounds of Istrian dry-cured ham from 2010 and 2012 were investigated by using headspace-solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS). Samples of biceps femoris were also evaluated by measuring physical and chemical characteristics. 92 volatile aroma compounds of Istrian dry-cured ham were found. Volatile compounds belonged to several chemical groups: aldehydes (51.4; 51.3%), terpenes (16.5; 16.4%), alcohols (15.5; 13.2%), ketones (8.6; 7.4%), alkanes (3.8; 5.7%), esters (1.3; 1.6%), aromatic hydrocarbons (0.8; 3.9%) and acids (0.6; 0.9%). Principal component analysis (PCA) showed that fat content, tenderness and melting texture were positively correlated. Terpenes were strongly correlated with flavour of added spices. Sweet taste and the presence of esters were positively correlated as well as negative odour, raw meat flavour and water content.

Enrichment of eggs in n-3 polyunsaturated fatty acids by feeding hens with different amount of linseed oil in diet.

The production of n-3 polyunsaturated fatty acid enriched eggs by addition of linseed oil to the laying hens' diet has been evaluated in terms of production parameters and n-6/n-3 ratio. A total of 150 18weeks old Lohmann Brown laying hens were housed in cages and fed with basal diet and four experimental diets containing 1%, 2%, 3% or 4% of linseed oil added to the basal diet. The effect of the altered level of linseed oil on hens laying performance, fatty acid content and composition and cholesterol content in egg yolk has been evaluated during 13weeks of experiment. Egg weight, yolk fat content, yolk weight, yolk percentage and shape index were not influenced by dietary treatment. The ratio between n-6 and n-3 polyunsaturated fatty acids in eggs decreased in first 5weeks and then remained stable until the end of the experiment for all experimental groups. Different contents of linseed oil in feed highly influenced the n-6/n-3 ratio (P<0.0001). Addition of linseed oil did not influence the cholesterol content in yolks (P=0.5200) while the only factor affecting the cholesterol content was the hens age (P<0.0001).

Characterization of traditional Istrian dry-cured ham by means of physical and chemical analyses and volatile compounds.

The aroma-active compounds of Istrian dry-cured ham were investigated by using headspace-solid phase microextraction and gas chromatography-mass spectrometry (GC-MS). Samples of biceps femoris were also evaluated by measuring physical and chemical characteristics: moisture, protein, fat, ash and NaCl content, a(w) value; colour: L*, a*, b* and oxidation of fat: TBARS test. About 50 volatile compounds were identified and quantified which belonged to several classes of chemical: 5 alcohols, 8 aldehydes, 7 alkanes, 1 ketone, 2 esters, 9 monoterpenes and 15 sesquiterpenes. Except volatile compounds derived from lipolysis and proteolysis the most abundant constituents were terpenes (62.97; 41.43%) that originate from spices added in the salting phase of the production process.

Resistance of Listeria monocytogenes, Escherichia coli O157:H7 and Campylobacter jejuni after exposure to repetitive cycles of mild bactericidal treatments.

While maintaining nutritional and sensorial attributes of fresh foods mild processing technologies generally deliver microbiologically perishable food products. Currently little information exists on possible increase in the resistance of pathogens after repetitive exposure to mild (sub-lethal) treatments. Multiple strain-cocktails of Listeria monocytogenes, Escherichia coli O157:H7 and Campylobacter jejuni were exposed to 20 consecutive cycles of sub-lethal inactivation by three different techniques. Used techniques comprised inactivation with lactic acid (LA), chlorine dioxide (ClO(2)) and intense light pulses (ILP). Results showed that the selection of resistant cells was both species and technique dependent. While repetitive cycles of ClO(2) treatment did not result in increased resistance, repetitive inactivation with LA yielded L. monocytogenes culture of higher resistance in comparison to the parental culture. The increased resistance, expressed as decreased level of reduction in bacterial counts in subsequent inactivation cycles, was also observed with ILP for both L. monocytogenes and E. coli O157:H7 strains. Visual trend observations were confirmed through statistical linear regression analysis. No such effects were noted for C. jejuni which became undetectable after first 2-5 cycles. Current findings indicate the ability of foodborne pathogens to adapt to mild bactericidal treatments creating new challenges in risk assessment and more specifically in hazard analysis.

Treatment of Escherichia coli O157:H7 with lactic acid, neutralized electrolyzed oxidizing water and chlorine dioxide followed by growth under sub-optimal conditions of temperature, pH and modified atmosphere.

The utilization of sub-lethal decontamination treatments gains more and more interest due to the increased consumers' demand for fresh, minimally processed and convenient food products. These products rely on cold chain and hurdle (combination) technology to provide microbiological safety and quality during their shelf life. To investigate the ability of surviving cells to resuscitate and grow in a food simulating environment, sub-lethal decontamination treatments were coupled with subsequent storage under sub-optimal growth conditions. For this purpose chlorine dioxide (ClO2) and neutralized electrolyzed oxidizing water (NEW)-treated cultures of Escherichia coli O157:H7 were inoculated in TSB-YE of pH 5.8 and aw 0.99, and stored at 10 degrees C, 12.5 degrees C and 15 degrees C, under four different atmospheres (0%, 30% and 60% CO2 balanced with N2, and air). Due to the severity of injury, lactic acid-treated cells were inoculated in TSB-YE pH 7.0. Data obtained reveal that the fraction of sub-lethally injured E. coli O157:H7 undergoes an additional inhibitory effect during the storage period under of sub-optimal conditions. Observed extension in the lag growth phase was a direct consequence prior sub-lethal injury. The effects of liquid ClO2 and NEW were less pronounced in comparison to lactic acid. The current study signifies the potential utilization of appropriate combination of different extrinsic and intrinsic factors in the elimination or growth inhibition of food-borne pathogens.