Moisture content and particle size of dehydrated egg yolk affect lipid and cholesterol extraction using supercritical carbon dioxide.

Egg yolk was spray-dried under conditions to produce a small particle size powder and a large particle size powder. Particle size was determined using a Nikon Optiophot microscope. Spray-dried egg yolk was also adjusted to various moisture levels as follows: control (2 to 4% moisture), 7% moisture, and 12% moisture. Supercritical carbon dioxide extraction (SCE) of each of these moisture treatments at 45 C/306 atm using 30 g CO2/g of sample was completed. For the particle size study, 45 g CO2/g of sample at 45 C/306 atm was utilized. Particle size exhibited a significant effect on cholesterol and lipids extracted using SCE. As moisture content of dried egg yolk increased to 7%, there was a significant increase in lipids extracted using supercritical carbon dioxide. Moisture content had no significant effect on cholesterol extraction. After extracting SCE higher moisture spray-dried egg yolk, sponge cake volume was significantly reduced compared to that of the control. The reduced sponge cake volume may be due to protein denaturation.

The combined influence of dietary flaxseed variety, level, form, and storage conditions on egg production and composition among vitamin E-supplemented hens.

Trial 1 tested the effects of ground vs whole flaxseed at dietary levels of 5, 10, or 15% compared to a corn-soybean or fish oil control on egg production of Leghorn hens over a period of 8 wk. Dietary flaxseed decreased feed consumption, weight gain, and egg weights compared to the control diets; however, flaxseed and fish oil significantly improved egg production (88.9 and 93.0%, respectively) compared to the control (83.1%). Incorporation of linolenic acid (C18:3n-3) into the egg increased linearly as the level of dietary flaxseed increased (2.31, 4.18, or 6.83% of the yolk fatty acids for 5, 10, and 15% flaxseed diets, respectively). In Trial 1, flaxseed and fish oil significantly increased percentage white and decreased percentage yolk compared to the control treatment but had no effects on egg cholesterol. Trial 2 was a factorial design of varieties of flaxseed (brown vs golden), types (ground vs whole), levels of dietary vitamin E (27 vs 50 IU/kg), and feed storage temperatures (4 vs 21 C) fed to hens for 6 wk. Brown flaxseed significantly increased egg weight and egg production compared to the golden variety. There was no difference in whole vs ground flaxseed for measured production variables. Vitamin E (50 IU) significantly improved egg production (96.1 vs 94.3%) compared to 27 IU. Storage temperature of flaxseed did not significantly affect any production variables. In conclusion, dietary flaxseed can be safely added whole to layer diets up to 15% without any detrimental effects on hen-day egg production. Levels of 10 to 15% flaxseed yield eggs with 4 to 7% yolk n-3 fatty acids, respectively, making these eggs rich sources of n-3 fatty acids.

Textural, color, and sensory properties of bologna containing various levels of washed chicken skin.

Poultry skin was washed in sodium bicarbonate (0.5%) solution in a pilot plant facility to remove fat from skin. Composition of the washed product was determined and its functional properties were determined in a bologna product at the levels of 0, 10, and 20%. Washing reduced fat, and increased total protein and moisture in skin. Collagen content was significantly increased and water- and salt-soluble protein in washed skin were significantly decreased compared to unwashed skin (P < 0.05). With reference to emulsion stability, skin content did not affect fat or gel-water losses and lowered solids loss when compared to bologna with 0% skin (P < 0.05). Kramer Shear peak force was not significantly different for bologna at each treatment level. Total energy was higher for bologna with 0% skin (P < 0.05). Skin addition did not affect compression measurements of hardness, springiness, cohesiveness, and chewiness when compared to bologna with 0% skin. The addition of skin resulted in a lighter (L), less red (aL), and less yellow (bL) product according to HunterLab color analysis (P < 0.05). Consumer panelists rated bologna with 10% skin highest in texture, flavor, and texture and appearance acceptability (P < 0.05). Washed chicken skin may have potential as a low cost, low fat ingredient for emulsified meat products.

Inhibition of Salmonella typhimurium on agar medium and poultry skin by ultraviolet energy.

Ultraviolet radiation (UV) was effective in destroying Salmonella typhimurium on agar plates and poultry skin. Agar plates inoculated with varying numbers of colony-forming units (CFU) of S. typhimurium (1.2 x 10(2) to 1.7 x 10(9) were subjected to different doses of UV light to determine optimal killing. Poultry skin was also inoculated with varying CFU of S. typhimurium per 2 cm2 of skin and subjected to UV light. UV light treatment of inoculated agar plates revealed almost complete elimination (99.9%) of S. typhimurium at 2,000 microW x s x cm(-2). Bacterial reduction was less effective on the surface of poultry skin when a 80.5% reduction in S. typhimurium was obtained at 2,000 microW x s x cm(-2).

The use of ultraviolet radiation to reduce Salmonella and psychrotrophic bacterial contamination on poultry carcasses.

Broiler carcasses were subjected to ultraviolet (UV) energy (doses range from 82,560 to 86,400 muWs/cm2) at wavelength of 253.7 nm to evaluate the potential of this treatment for improving the microbiological quality of broiler carcasses. Broiler chicken halves were inoculated with a marker strain of Salmonella typhimurium 5 min prior to treatment. A 61% reduction in viable S. typhimurium was observed in UV-treated chicken halves as compared with untreated halves. The UV energy treatment had no deleterious effects on color (Hunter L, aL, or bL) or 2-thiobarbituric acid (TBA) values. After 10 d of storage at 7 C, TBA values of thigh meat were 1.3 mg malonaldehyde/kg meat compared with 1.7 for controls. Psychrotrophic bacteria populations were not appreciably altered by UV treatment when their numbers were compared with bacterial counts obtained from untreated chicken halves held for 10 d at 7 C. This study suggests that UV radiation can reduce Salmonella surface contamination without negatively affecting carcass color or increasing rancidity of the meat.

Supercritical carbon dioxide extraction of lipids and cholesterol from dehydrated chicken meat.

Supercritical carbon dioxide (SC-CO2) extraction was studied for removal of lipids and cholesterol from dried chicken meat powder and chunks. Two combinations of pressure and temperature were used: 299 atm and 45 C, and 381 atm and 55 C, both providing a fluid density of .90 g/cm3. For a given quantity of CO2, at the higher temperature and pressure, significantly (P < .05) more lipids and cholesterol were extracted from the powder. At 381 atm and 55 C, approximately 89% of the lipids and 90% of the cholesterol were removed from the dehydrated chicken meat powder. With respect to the chunk chicken meat, about 93% of the lipids and 82% of the cholesterol were extracted at 299 atm and 45 C. It seemed that the SC-CO2 extraction process was more efficient when chunks were used. Protein was concentrated as cholesterol and lipids were removed by SC-CO2 extraction of both chicken meat types, and Hunterlab L values increased but aL values decreased, indicating a lighter color with less redness. This research indicated that SC-CO2 extraction holds promise for substantially reducing lipids and cholesterol in chicken meat.

The effect of lysozyme and ethylenediaminetetraacetic acid on Salmonella on broiler parts.

A dip system, consisting of lysozyme (1 mg/ml) and ethylenediaminetetraacetic acid (EDTA) (5 mg/ml), was studied to determine its effect on Salmonella-contaminated broiler parts. Enumeration of S. typhimurium from the broiler parts showed that both lysozyme and a lysozyme-EDTA mixture gave a significant reduction in the number of viable organisms. In a trypticase-soy broth solution, Salmonella growth was inhibited by EDTA while lysozyme showed little effect.