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In this study, varying concentrations of polyunsaturated fatty acids in goat’s milk were obtained by supplementing goat feed rations with maize dried distillers grains with solubles (DDGS). In comparison to the control group, the milk of goats that received DDGS contained about 25% more polyunsaturated fatty acids, 30% more conjugated linoleic acid (CLA), and had more favorable values of the atherogenic and thrombogenic indices. The diverse composition of fatty acids present in the goat’s milk correlated with the olfactory perception of the milk and its volatile compound profile. The level of unsaturated fatty acids significantly affected the odors detected in the processed goat’s milk. The volatile compound profile of the milk was mostly differentiated by the concentrations of aldehydes (hexanal and furfural) and furanones (furaneol), which exceeded their odor threshold values. The total concentration of identified aldehydes was highest in pasteurized milk samples from the goats of the experimental group, as a result of heating. Furfural was found in pasteurized samples of both the control and experimental milk at concentrations exceeding its odor threshold (3 mg·kg−1). Feeding goats with DDGS did not change the animal, cooked, dairy fat, lack of freshness, light-oxidized, or overall dairy flavors of the raw milk. After pasteurization, milk from goats fed with DDGS retained its characteristic animal odor and gained a very intense cooked flavor.

Mare milk is a valued and sought-after raw material for the production of innovative dairy products. The high demand, low supply, high price, and lack of accurate characterization of the milk of a given horse breed may provoke its deliberate fraudulent dilution. The aim of this work was to analyze the freezing point against a background of various selected technological parameters of Polish Coldblood mare milk. Research was carried out on multiparous Polish Coldblood mares from 5 to 8 yr of age with live weights between 618 and 851 kg. Their milk was tested on d 1, 3, and 7 postpartum and once a month for the next 9 mo of lactation (n = 52). Milk from 13 mares, taken daily in mo 4 of lactation, was collected for the dilution study (n = 403). The basic composition of the milk was as follows: solids-not-fat, 84.4 g/kg, fat 15.1 g/kg, lactose 65.3 g/kg, and total protein 24.2 g/kg (made up of casein, 14.6 g/kg, and whey protein, 9.5 g/kg). The dominant amino acids were glutamic acid, proline, leucine, and aspartic acid. The mean freezing point during a 9-mo lactation was -0.557°C (coefficient of variation = -2.787; 5th to 95th percentile: -0.563 to -0.550°C). Based on our analysis, we adopted -0.550°C (from 3 to 6 mo) as the reference value for milk from the Polish Coldblood horse. Analysis of the model of changes in freezing point, after dilution, using the coefficient of determination and Akaike's information criterion, showed that a linear model could be recommended (y = 79.35 + 144.35x). Addition of 1% water increased the freezing point of Polish Coldblood mare milk by 0.0069°C.

The aim of this study was to analyse the metabolic activity of lactic acid bacteria and yeast based of changes in electrical conductivity and electrical impedance during fermentation of goat milk and mixtures of goat’s milk and mare’s milk (1:1, 1:2). As a result of fermentation, conductivity increased 1.4-fold. The conductivity of kefir prepared from goat and mare milk mixed at a ratio of 1:2 (6.210 Ω-3∙cm-1) was lower than that of the 1:1 mixture or of goat milk alone (7.242 Ω-3∙cm-1). A significant dependence of electrical conductivity and pH (0.970 ≤ r ≤ 0.993) was recorded during fermentation. The addition of mare milk to goat milk significantly slowed down the growth of LAB (Δλ = 0.8 h) and yeasts during kefir production.

The aim of the study was to produce fermented ewe’s milk with an increased ratio of native whey proteins and to characterize selected properties (metabolic activity, mono- and disaccharides, lactic acid and ethanol content, aroma profile, texture, color and sensory properties) of experimental milk and final product. Increasing the ratio of whey proteins to caseins in experimental milk resulted in higher activity of microorganisms belonging to the starter culture used in fermentation and higher content of volatile ketones in total volatile compounds identified during experiment. Increase in the lactic acid content and brightness parameter in fermented milk was observed in product made from experimental milk with modified ratio of whey proteins to caseins. It was concluded that changing the ratio of the main protein fractions in experimental milk differences in the physical and chemical properties of the final product, but these changes did not have a negative influence on sensory properties and product desirability.

Summary The degree of lactose hydrolysis and exogenous lactase activity of fermented mare's milk (MM) mixed with cow's (CM), sheep's (SM) and goat's milk (GM) was investigated. Moreover, the overall sensory desirableness of the novel products was also evaluated. A mixture MM + CM, or MM + GM, or MM + SM at a 1:1 ratio, significantly reduced the amount of contained lactose (P

Color is important for the consumer when making a purchase decision. Mare&rsquo, s milk and, thus, fermented mare&rsquo, s milk is little known to consumers. Thus, it is worth presenting research showing the extent of color change during the production and storage of mare&rsquo, s milk. Herein, we examined the range of color changes in mare&rsquo, s milk and cow&rsquo, s milks adapted to mare&rsquo, s milk composition. These samples were further fermented and stored for 3 weeks at 5 &plusmn, 1 &deg, C. Starter cultures containing Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus were used for fermentation. Mare&rsquo, s milk reached the required pH of 4.5 during fermentation faster (255 min) than cow&rsquo, s milk (300 min). After fermentation, mare&rsquo, s milk compared to cow&rsquo, s milk and adapted cow&rsquo, s milk had lower titratable acidity (0.75%) and firmness (145. 6 |(g∙s)|). The water holding capacity (95.6%) and number of Lactobacillus (7.71 log CFU/mL) and Streptocococcus (7.20 log CFU/mL) in mare&rsquo, s and other&rsquo, s milks were the same. Mare&rsquo, s milk was furthest from the ideal white (WI) color, with its chrome (C*) being 1.5-times larger than cow&rsquo, s milk. However, fermented mare&rsquo, s milk was darker than the fermented adapted milk and cow&rsquo, s milk by 36% and 58%, respectively. Storage caused a decrease in the WI, C*, and yellowness index (YI). The fermented mare&rsquo, s milk color stability during production and storage was less than that of fermented cow&rsquo, s milk. After 3 weeks storage, it was observed that the titratable acidity increased to 1.05%, and the pH decreased to 4.3 in fermented mare&rsquo, s milk. The water holding capacity decreased but was still higher compared to fermented cow&rsquo, s milk.

Camelina sativa cake (CS), a rich source of unsaturated fatty acids, in the case of ruminants may improve the energy value of a diet and also increase the unsaturated fatty acid content in milk. Effects of basal diet (control) and basal diet plus 12 g 100 g −1 of CS in concentrate dry matter on fatty acid composition of goat's milk and kefir made from this milk were examined with particular emphasis on the contents of monoenes and conjugated isomers of linoleic acid. A total of 66 goats of the Polish White Improved breed were divided into two groups – the control and receiving CS. The diets were administered to animals for 30 days. Elevated concentrations of total monounsaturated fatty acids, the effect of an increased levels of monounsaturated fatty acids in the trans configuration as well as an increased content of total polyunsaturated fatty acids resulted from CS supplementation. Total saturated fatty acid concentration was decreased. Milk from CS-supplemented goats and kefir made from this milk were characterized by increased levels of beneficial nutritional factors, including mono- and polyunsaturated fatty acids.

BACKGROUND The composition of bioactive components in dairy products depends on their content in raw milk and the processing conditions. The experimental material consisted of the milk of dairy goats supplemented with 120 g d−1 per head of false flax cake. The aim of the study was to evaluate the quality of kefir produced from goat's milk with a higher content of bioactive components resulting from supplementation of the goats' diet with false flax cake. RESULTS The administration of false flax cake to goats had a positive effect on the fatty acid profile of the raw milk, causing an increase in the proportion of polyunsaturated fatty acids (PUFA), including conjugated linoleic acid (CLA) and n-3 fatty acids. Their increased percentage was detected in the kefir after production as well as after storage. The processing value of the harvested milk did not differ from the qualitative characteristics of milk from goats of the control group. Increasing the proportion of bioactive components in goat's milk did not result in changes in the acidity, texture, colour, flavour, aroma or consistency of the kefir obtained. CONCLUSION Milk and kefir obtained after the administration of false flax cake to goats contain bioactive components (PUFA including CLA, n-3 and monoenic trans fatty acids) in significant amounts. Kefir from experimental goat's milk did not differ in quality from kefir made from the milk of the control group. © 2014 Society of Chemical Industry

The aim of this study was to characterize functional fermented caprine milk. Functional properties of fermented milks was an effect of increasing the level of whey proteins, MUFA and PUFA content in final product Milk used for experiments was obtained from experimental station belonging to Poznań University of Life Sciences. Feeding strategy was included modification by adding 12% of Camelina sativa cake. The fermentation process was done by using Lactobacillus acidophilus, Lactobacillus spp., and kefir grain microflora. The quality properties which were considered was metabolic activity, monosaccharide, disaccharide, lactic acid and ethanol content, aroma and fat profile. It was noted that increasing the content of functional components in processed milk caused changes in lactose, MUFA, PUFA and volatile acids content in final product.

Degradation of cholesterol during storage of UHT treated bovine and caprine milk was assessed. Cholesterol contents were 11.78 and 8.51 mg 100 mL −1 , respectively. During storage for 6 months, the cholesterol amounts decreased irrespective of the milk type and storage conditions. The total contents of cholesterol oxidation products (COPs) observed in raw bovine and caprine milk were 50 and 38 μg 100 mL −1 , respectively. Regardless of the type of milk and storage conditions, a significant increase in the total amounts of oxysterols was observed. After 6 months storage of UHT bovine milk, the content of COPs increased to 217 and 248 μg 100 mL −1 for milk stored at 4 °C and 20 °C, respectively, whereas in caprine milk the amount increased accordingly to 160 and 249 μg 100 mL −1 . These results confirmed formation of oxysterols in UHT milk during storage, with temperature and time being the most important factors.

Smoking of cheeses significantly modifies not only sensory attributes, but also determines the form of their further utilisation, packaging method and shelf life. The aim of thIS study was to evaluate functional characteristics of smoked and unsmoked Mozzarella cheeses subjected to 4-week storage. It was found that smoked cheese contained 7% less water than unsmoked cheese. Meltability of smoked cheese before storage was 2 times smaller than that of unsmoked cheese, but after 4 weeks, meltability was 21% greater. Smoked cheese not subjected to storage was 2.2 times harder than unsmoked cheese. During storage, hardness of smoked cheese decreased 4.6-fold, while that of unsmoked cheese only 1.1-fold. Storage time had an increase in stretchability of unsmoked and smoked cheeses by 4.2 and 14.9%, respectively. Keywords: Mozzarella, meltability, texture

BACKGROUND:OscypekisaspecialtypeofPolishsmokedewecheesewithauniqueflavourdescribedasslightlysour,piquant, saltedandsmoked.Inthisstudythevolatile,sensoryandmicrobialprofilesofOscypekcheesewereanalysedduringitsvarious preparation stages of curding, scalding, brining and smoking. RESULTS:Thesmokedewecheesewascharacterisedby54volatilecompoundsbelongingtoninedifferentchemicalgroups(free fatty acids, esters, ketones, alcohols, aldehydes, furans/furanones, phenols, sulfur compounds, terpenes). The sensory aroma profile analysis of unsmoked and smoked cheese showed an important correlation with the analysis of volatile compounds. The microbial profile data indicated that in smoked cheese such as Oscypek the levels of selected bacteria diminishedafter the curding stage as a result of the subsequent scalding, brining and smoking stages. CONCLUSION: From the results it can be concluded that, although the analysed smoked cheese consisted of three groups of compounds, the first derived from biochemical reactions (free fatty acids, esters, ketones, alcohols, aldehydes, sulfur compounds), the second from smoking (furans and furanones, phenols) and the third from milk flavour (terpenes), it is the smoking process that mainly influences its typical flavour. c � 2011 Society of Chemical Industry

In this study, the effect of the lactation stage on changes in the fat and cholesterol content and fatty acid composition of colostrum and milk of Wielkopolska mares' was investigated. Colostrum and milk samples from 10 lactating mares were collected at the beginning of lactation, on the 1st and 2nd day after foaling and then, starting from the first month of lactation, at 4 weeks' intervals up to the fifth month of lactation. Statistically significant differences were found between mares' colostrum and milk in the fat and cholesterol content as well as in the percentage rate of total fatty acids which occurred in significant quantities. Together with the lengthening of the lactation time, the content of fat and cholesterol in the mares' milk was observed to decrease. The authors also found a significant impact of the lactation period on changes in the ratio of polyenoic fatty acids from the n-6 to n-3 family. Bearing in mind the fat and cholesterol content and a more favourable (from the nutritional point of view) ratio of fatty acids from the family of n-6 to n-3, it is recommended to collect milk from mares in the 4th and 5th month of lactation.

This article explored the formation of volatile compounds during the production of kefir from goat and sheep milks with high polyunsaturated fatty acids (PUFA) as a result of feeding animals forage supplemented with maize dried distillers grains with solubles (DDGS). The increased PUFA content of the goat and sheep milks resulted in significant changes to the fermentation process. In particular, apart from an increase in the time taken to ferment sheep milk, fermentation yielded less 2,3-butanedione. The highest quantities of this compound were assayed in kefir produced from goat milk with an increased content of PUFA. An increase of PUFA significantly elevated ethanal synthesis during lactose-alcohol fermentation of sheep milk. Neither the origin of milk (sheep or goat) nor the level of PUFA had any statistical effect on the amount of ethanal assayed during the fermentation of milk and within the finished product. The proportion of l(+)-lactic acid was higher in kefirs produced using goat milk compared with sheep milk and did not depend on the content of PUFA in milk fat. The content of PUFA had a significant effect on the aroma profile of the resulting kefirs. An increase in PUFA content resulted in the loss of whey aroma in goat milk kefirs and the animal odor in sheep milk kefirs, and a creamy aroma became more prevalent in kefirs made from sheep milk.

The aim of this study was to determine the effect of sodium lactate addition on shelf-life extension of sliced poultry sausage packaged both in air and nitrogen atmospheres and stored in refrigerated conditions. Basic chemical composition, pH, and malonaldehyde content were assayed and color measurement using the reflection method was carried out. Microbiological examination consisted of determination of total number of aerobic psychrotrophic bacteria and number of lactic acid bacteria. Sensory evaluation of products was performed. Microbiological and sensory quality of sliced poultry meat sausage was dependent on the addition during production of sodium lactate and the composition of gases (air or nitrogen) used in packaging. Slices of poultry sausage with 1% as well as 2% of sodium lactate maintained their initial quality of evaluated sensory attributes longer, irrespective of the applied gases. Sodium lactate inhibited growth of aerobic psychrotrophic bacteria and lactic acid bacteria during refrigerated storage. Sodium lactate also inhibited the formation of malonaldehyde in sliced poultry sausage during refrigerated storage. The effectiveness of this process depended on the concentration of sodium lactate addition. It was concluded that 1% as well as 2% addition of sodium lactate could extend the shelf life of sliced poultry sausage packaged in air atmosphere and stored at 5 to 7 degrees C by 3 or 4 times, respectively. Sliced poultry sausage treated with 2% sodium lactate packed in nitrogen had the longest (35-day) shelf life. This was a sevenfold increase in the shelf life of sliced poultry sausage compared with the control.

The purpose of the study was to identify and quantitate the individual phospholipids, to determine the fatty acid profile of each individual phospholipids fraction in chiken liver, heart, plasma, and egg yolk, and to study the roles of individual phospholipids in thiobarbituric acid reactive substance formation in edible poultry products.

Fatty acid profiles and distribution of individual phospholipids (PL) in the total PL were determined in chicken meat and skin and swine aortas, and the contribution of each PL to malondialdehyde (MDA) formation was studied. Results indicate that phosphatidyl choline (PC) and phosphatidyl ethanolamine (PE) produced 70-77% of the total PL MDA while 16-25% of the MDA was formed by phosphatidyl inositol (PI) and phosphatidyl serine (PS). Much lower concentrations of MDA (3-6%) were formed by sphingomyelin (SP), cardiolipin (CL) and lysophosphatidyl choline (LyPC). In all analyzed tissues, both the MDA concentration and the percentage of polyenoic fatty acids, especially arachidonic acid, were highest in PI followed by PE, PS, PC, CL LyPC, and SP.

From a total of 78 chickens, 24 carcasses were used to estimate the percentage for the individual cuts and their composition. Fifty-four carcasses were cut vertically into halves of which two-thirds were quartered, yielding front and hind quarters (Cuts 2 and 3). Half of these quarters were cut into individual pieces, yielding breasts and thighs with back ribs, drumsticks, and wings. The muscles and skin of one-third from each of the seven different cuts described above were analyzed raw for lipid oxidation products; while the remaining two-thirds were microwaved. Half of the microwaved cuts were analyzed 2 hours after cooking; the other half, after 4 days of storage at 4 C. The results indicated that the absolute amount of lipid oxidation products in chicken muscles and skin after microwave cooking and refrigerated storage was affected by the initial level of those products in the raw samples and by the particular cut of meat Cooking the different cuts of chicken carcasses by microwave significantly increased the amount of malonaldehyde (MA) and lipid-oxidation fluorescent products (LOFP) in the aqueous phase of Folch-extracted muscles and skin and in the organic phase of Folch-extracted skin lipids. Microwave cooking for the separate broiler parts (especially the drumsticks and wings, as compared to halves or quarters) produced the lowest amount of lipid oxidation products due to the shorter cooking time. Refrigerated storage of broiler parts cooked by microwave produced substantial amounts of MA and LOFP in the aqueous phase of the Folch extracted skin and in the organic phase of the Folch-extracted lipids from the muscles.

The muscles and attached skin of fresh chicken broiler parts, which were roasted in a convection oven and subsequently kept at 4°C for 4 days were analyzed for lipid oxidation products (LOP). Roasting and refrigerated storage significantly increased the amount of malonaldehyde which occurred faster in the skin than in the muscles. Also, after roasting, lipid oxidation fluorescence products increased in the aqueous phase and, after refrigerated storage, in the organic phase of Folch extracted muscles and skin. The lowest concentration of LOP was found in roasted, separated parts of broilers, especially in the drumsticks and wings as opposed to roasted carcass halves or quarters. The absolute amount of LOP in muscles and skin after roasting was a result of initial concentrations of LOP in raw samples and the type of roasted broiler parts.

A feeding experiment with brown layers was carried out to find effects of graded levels of rapeseed (without, 15% and 30%) in layer diets on the fatty acid composition of egg yolk and related functional properties of such modified eggs. A considerable increase of the content of essential n-3 fatty acids in egg yolk fat was noticed by including graded levels of rapeseed in layer diets. The destruction force of a gel prepared from whole egg was improved by the highest rapeseed level (30%) and emulsifying capacity by medium inclusion of rapeseed in layer diets (15%). The thermal stability of an emulsion prepared from whole egg was not influenced by rape feeding. Viscosity of mayonnaise prepared from egg yolk and whole egg yolk was decreased by increased rapeseed levels in the diets. In tendency, organoleptic evaluation of sponge cake prepared from whole egg revealed better results for the control group. The baking height of sponge cake was improved by rapeseed inclusion in layer diets. It may be assumed that all these changes caused by rapeseed feeding are closely related to the mentioned changes in the fatty acid profile. Einflus eines veranderten Fettsaurenprofils des Eidotterfetts auf technologische Eigenschaften von Huhnereiern. Es wurde ein Futterungsversuch mit Hennen, die braunschalige Eier legen, durchgefuhrt, um den Effekt steigender Rapssaatanteile (ohne 15 und 30%) im Legehennenfutter auf die Fettsaurenzusammensetzung des Eigelbs sowie damit verbundene funktionelle Eigenschaften solcher Eier zu untersuchen. Mit steigendem Rapssaatanteil im Legehennenfutter wurde ein betrachtlicher Anstieg im Gehalt an n-3 Fettsauren des Eidotters festgestellt. Der Strukturwiderstand des Eigels und die Emulsionsfahigkeit wurden mit der hochsten (30%) bzw. mit der mittleren Rapszulagestufe (15%) verbessert. Die thermische Stabilitat einer Emulsion, die aus dem Gesamtei hergestellt wurde, war von der Rapsfutterung nicht beeinflust. Die Viskositat der Mayonnaise, hergestellt aus Eigelb bzw. Gesamtei, verringerte sich mit steigen dem Rapssaatanteil im Futter. Die organoleptische Einschatzung des Biskuits, hergestellt aus dem Gesamtei, fiel in der Tendenz fur die Kontrollgruppe gunstiger aus. Die Hohe dieser Biskuits war dabei mit der hochsten Rapszulagestufe signifikant erhoht. Es kann angenommen werden, das alle untersuchten funktionellen Eigenschaften auf die erwahnten Anderungen im Fettsaurenprofil der Eier zuruckzufuhren sind.

This experiment tested whether the lipid composition of pork could be altered by changes in dietary lipid, that what effects these changes would have on production and meat characteristics. Pigs were fed diets containing 10 or 20%+ extruded full-fat soybeans (FFS) or 4% tallow for a 3- or 6-wk finishing period, with a corn-soybean meal diet fed as a control. Seventy barrows and 70 gilts were allotted into seven treatment groups with four pens per group. Analysis was on 28 experimental units, which were composite samples from pens. The significance of treatment, sex, and treatment x sex interaction F-statistics was evaluated on chloroform-methanol extractable total lipid, triacylglycerol, phospholipids, cholesterol, individually fatty acids (FA), and the major classes of FA obtained from longissimus muscle and bacon. Treatment effects (P less than .05) were detected for cholesterol content of longissimus and for total lipid and phospholipid content of bacon. Treatment effects (P less than .01) were detected for monoenoic, dienoic, and polyenoic (P) FA in both tissues, and for saturated (S) FA in bacon (P less than .05). Treatment effects (P less than .001) were detected in both tissues for the P:S ratio. The P:S ratio increased 54% for longissimus and 100% for bacon in the pigs fed FFS for 6 wk compared with pigs consuming a corn-soybean meal diet.

Fresh breast and leg meat was collected from 11-wk-old pullets fed a high protein-low fat starter ration. Lipid oxidation measured in malonaldehyde (MA) equivalents in total fat extracted from meat, and in phospholipids (PL), triacylglycerol (TG), and cholesterol ester (CE) fractions of total fat was determined by an improved TBA assay with antioxidant protection. It was found that breast meat had two-fold less fat than leg. Breast fat contained 70.1% PL, 22.2% TG, and 1.2% CE; leg fat contained 42.9% PL, 51.4% TG, and 0.8% CE. After separation by thin layer chromatography, the individual lipid classes were tested for TBA reactivity. The PL fraction was found to contribute approximately 90% of the MA measured in total fat from chicken meat.

Whole fat from chicken liver, heart, adipose tissue, and plasma was extracted with chloroform-methanol solvents. Fat content of tissues was determined, and total fat was analyzed for lipid composition by chemical assay, for malonaldehyde content by improved thiobarbituric acid (TBA) assay with antioxidant protection, and for fluorescence excitation (360 nm) and emission (440 nm) spectra. The fatty acid composition of isolated phospholipids and triglycerides from each tissue was also determined. Liver contained 5.56% fat composed of 42.3% phospholipids, 51.2% triglycerides, and 6.2% total cholesterol; heart contained 4.27 % fat composed of 47.6% phospholipids, 46.9% triglycerides, and 5.3% total cholesterol; and adipose tissue contained 79.4% fat composed of .7% phospholipids, 99.1% triglycerides, and .1% total cholesterol. Plasma contained 1.25% fat composed of 45.6% phospholipids, 31.4% triglycerides, and 22.3% total cholesterol. Compared to the fatty acids of triglycerides, the fatty acids from tissue phospholipids were much more polyunsaturated with prominent amounts of arachidonic acid. Generally, fats with large phospholipid fractions also had relatively large concentrations of malonaldehyde. The concentration of malonaldehyde in fat from adipose tissue, which contained less than 1% phospholipids, was more than 50 times lower than in fat from other tissues studied. The relative levels of fluorescent products in fat from tissues followed the pattern established for malonaldehyde levels in those tissues. Because of the widely variable fat content of different tissues, the concentration of malonaldehyde in extracted fat appeared to be a more useful parameter for evaluating potential oxidative rancidity than the TBA number.

Oxidation products were measured in chicken breast and leg meat during a series of common household processing steps (frozen storage, microwave and convection cooking, refrigerated storage after cooking, and reheating). Malondialdehyde (MDA) in fat from meat was measured by an improved thiobarbituric acid (TBA) assay with antioxidant protection; and fluorescent products (FP) were measured in organic and aqueous layers from Folch-extracted meat samples by fluorescence spectrophotometry. Fat from breast meat contained almost twice as much MDA and FP than fat from leg meat due to a greater content of phospholipids, which had a large amount of polyunsaturated fatty acids. Leg meat had higher TBA numbers, however, because it contained twice as much fat as breast meat. Fresh, 3-month, and 6-month frozen storaged meats cooked by convention oven and then further processed had higher MDA and TBA values compared with microwave cooked and processed meats, but a significant difference (P

Total fat extracted from breast meat, leg meat, and breast skin was analyzed for composition of phospholipids (PL), triglycerides (TG), and total cholesterol (C); and for fatty acid composition of PL and TG fractions. Whole fat was also analyzed for malonaldehyde (MA) by an improved thiobarbituric acid (TBA) assay with antioxidant protection and for certain secondary oxidation products by fluorescence excitation (360 nm) and emission (440 nm) spectra. Breast contained 1.1% fat composed of 58.4% PL and 35.5% TG; leg contained 2.4% fat composed of 32.1% PL and 62.9% TG, and skin contained 32.8% fat composed of 1.6% PL and 97.8% TG. Fatty acid compositions of TG fractions from all tissues were similar and contained almost no polyunsaturated fatty acids (PUFA) with 20 or 22 carbon atoms. Fatty acids from PL fractions of meat contained more than 20% arachidonic acid and substantial amounts of PUFA with 22 carbon atoms; skin PL contained approximately one-half the PUFA with 20 and 22 carbon atoms compared with meat. The MA concentration in breast fat was 1.9 times higher than in leg fat and 20.3 times higher than in skin fat. However, because of the different fat content of tissues, the TBA number of skin was higher than that of leg, which in turn was higher than that of breast. The relative levels of fluorescent products in fat from meat and skin tissues clearly paralleled the trend found for MA concentrations. It was concluded that the TBA number parameter is of little comparative value unless accompanied by fat content and composition data.

Comparaison de 2 nouvelles methodes d'analyse de l'oxydation des lipides avec une methode classique, par distillation. La premiere methode utilise une extraction aqueuse, la seconde une extraction des lipides avant addition de BHT et mesure de l'indice TBA. La validite de chacune est testee sur de la viande fraiche, refrigeree ou congelee

Total lipid extracted from chicken breast, thigh, drumstick and wing muscles and the corresponding skin was analyzed for triacylglycerols and phospholipids as well as their fatty acid composition and also for malonaldehyde and lipid oxidation fluorescent products (LOFP) content. Muscles consist of only 1.2–3.2% lipid, but lipid concentration in the skin ranges from 22.2–31.7%. The percentage of phospholipid in muscle lipid was 20 times more than that of the skin. The fatty acids of triacylglycerols from muscles and skin contained less than 2% of polyunsaturated fatty acids (PUFA). Fatty acids from phospholipid of the meat contained over 15% arachidonic acid and substantial amounts of PUFA with 22 carbon atoms. Skin phospholipid had 10.6–13.2% of all PUFA. Differences in the lipid composition of muscles and skin resulted in a concentration of malonaldehyde in muscle lipids of 30–50 mg/g, a value more than 15 times greater than in lipids of the skin. However, the TBA number of the skin was the same or a little bit lower as compared to muscles. The relative levels of LOFP in the organic phase of Folch-extracted muscle and skin tissues paralleled the trend found for malonaldehyde concentrations. It was concluded that the simultaneous determination of total lipid content and malonaldehyde concentration in lipid extracted from various chicken muscles and corresponding skin was the most informative method for evaluation of precursors of lipid oxidation in fresh tissue.

The goal of this study was to examine the possibility of verifying the origin and authenticity of Polish cheese, Oscypek marked with protected designation of origin (PDO) label, based on its volatile profile. Oscypek and its false imitations Oscypek-like cheeses were analyzed using a solid-phase microextraction-mass spectrometry method (SPME-MS), which involved volatiles extraction by SPME with subsequent volatiles characterization by MS without particular components separation by gas chromatography. Collected data were treated using principal component analysis (PCA), linear discriminant analysis (LDA), soft independent modeling of class analogy (SIMCA), and support vector machines (SVM). The results of this study demonstrated that SPME-MS method combined with chemometric tools can be successfully used as electronic nose and applied to detect mislabeling and adulteration of PDO Oscypek cheese.

Four groups of 5-month-old chicken hens were given estradiol treatments and/or 5% dietary oil supplement for 14 days, after which blood plasma, liver, heart, and skeletal muscle were analyzed for lipid oxidation by TBA assay for malonaldehyde. Plasma from estradiol-treated birds had 8-fold higher levels of malonaldehyde compared to untreated birds. The bulk of this effect was due to a 5-fold increase in plasma lipid, but this lipid also contained a 70% higher concentration of malonaldehyde. Estradiol treatments produced significantly increased TBA numbers in liver, heart, and skeletal muscle. Corn oil supplementation significantly increased the malonaldehyde concentration in fat extracted from liver and heart, but not from plasma or skeletal muscle. It was concluded that estradiol treatment, in addition to generally increasing the deposition of fat in plasma and organs, also enhanced the concentration of malonaldehyde equivalents in plasma and organ fat.