On the structural and mechanical properties of mixed coconut and olive oil oleogels and bigels.

The interaction of monoglycerides and phytosterols in olive- and coconut oil on the structuring of oleogels was analyzed. Specifically, bigels with gelatin hydrogel in different ratios (40:60 and 60:40 w/w) were formed. The physicochemical and microstructural attributes of these systems were assessed. The olive oil to coconut oil ratio (0-100 w/w) and the added oleogelators affected the crystal structure and the mechanical properties of the oleogels. Polarized light microscopy revealed that the addition of coconut oil created a denser triglycerides crystal network and the presence of phytosterols created more needle-like crystals, enhancing the textural properties of the oleogels and of the resulting bigels. The hardness of the oleogels ranged from 0.50 N to 1.24 N and for bigels was 5.96-36.75 N. Bigels hardness decreased as the oleogel ratio in the bigel increased. Microscopy and FTIR revealed that the addition of coconut oil in oleogels hampered the formation of a distinct crystalline monoglycerides network. Also, the absence of new peaks in the bigels indicated that the two structured phases interact with each other mostly physically, without the formation of new chemical bonds. Consequently, the oleogels and bigels developed, comprise a promising hard fat substitute with improved nutritional profile.

Evaluation of bigel systems as potential substitutes to partially replace pork backfat in semi-dry sausages.

Bigels prepared with olive oil oleogels admixed with κ-carrageenan or κ-carrageenan and gelatin hydrogels (BG1 and BG2, respectively) were characterized with respect to microstructure and textural properties and were used as pork backfat alternatives in semi-dry sausages. Stable oleogel-in-hydrogel type bigels were formed, with BG2 having higher hardness values. Control sausages (CF) were formulated with 20% pork backfat and sausage treatments B1F and B2F had 50% of the pork backfat substituted by BG1 and BG2 bigels, respectively. Moisture, water activity, texture, microbial counts, sensorial and nutritional attributes of the resulting sausages were assessed during fermentation and after pasteurization and storage. Substituted sausages had increased weight loss, moisture, and water activity. Color evaluation revealed that the treatments with bigels exhibited the same trend in color formation and no differences were recorded in L* and a* values of the sausages. Total viable counts and lactic acid bacteria populations were not affected by the addition of bigel systems. Regarding the texture parameters, B2F semi-dry sausages exhibited similar values of hardness and cohesiveness to CF. Sausages formulated with bigels exhibited a reduction in energy (20%), fat (27%), saturated fatty acids (30%) and cholesterol (∼6%) content. B2F sausages had similar liking scores with CF, and they did not show any undesirable sensory attributes. The results demonstrate that bigels are a promising fat alternative to manufacture semi-dry meat products with lower fat content and a better nutritional profile.

Use of marination for controlling Salmonella enterica and Listeria monocytogenes in raw beef.

The effect of marination on the survival and growth of the pathogens Salmonella enterica and Listeria monocytogenes on beef pieces was investigated. Five marinades were used: soy sauce base marinade without (SB) or with lactic acid (SBLA), red wine base marinade without (WB) or with 0.5% v/v oregano essential oil (WBO), and sterile saline used as control (C). Inoculated fresh beef pieces were marinated for 18 h at 5 °C, removed from the marinade and subjected to storage trials at 5 °C and 15 °C. Heat inactivation studies were also performed on the isolates after exposure to the marinades to determine if marination affects heat resistance of the pathogens. The marinades with antimicrobials caused a significant decrease in viable count of the pathogens during marinations at 5 °C for 18 h of up to 2.1 and 3.4 log cfu cm(-2) for Salmonella and L. monocytogenes, respectively. Marinades without antimicrobials were less bactericidal resulting to reductions ranging from 0.3 to 0.4 and 1.3 to 2.0 log cfu cm(-2) for Salmonella and L. monocytogenes, respectively. Growth of L. monocytogenes was observed in the controls at both tested temperatures, while growth of Salmonella was observed in the controls stored at 15 °C. No growth of the pathogens was observed in any of the marinated samples at both temperature tested. No significant changes of heat resistance of the tested pathogens after exposure to the marinades were observed demonstrating the enhanced safety of the marinated beef product.

Effect of freeze-dried leek powder (FDLP) and nitrite level on processing and quality characteristics of fermented sausages.

Fermented sausages were produced with 0.84% and 1.68% freeze-dried leek powder (FDLP), providing 75 and 150 mg/kg NaNO(3), respectively, and three levels of added nitrite (0, 75, and 150 mg/kg NaNO(2). A control treatment was also produced with 150 mg/kg NaNO(2). Sausages with FDLP were darker and yellower (p<0.05) than the control. Higher FDLP levels produced less red, yellower and darker sausages (p<0.05). Lower FDLP levels resulted in higher (p<0.05) sensory scores for external appearance, flavour and overall acceptability. No differences were found among the treatments with FDLP plus 75 or 150 ppm NaNO(2) in TBA value, lightness, redness (cross section), redness stability, yellowness, texture parameters and sensory firmness, flavour and overall acceptability. The use of 0.84% FDLP and 75 ppm NaNO2 is considered more appropriate for the production of fermented sausages, as it results in a 50% reduction in added nitrite.

Efficacies of soy sauce and wine base marinades for controlling spoilage of raw beef.

Fresh beef slices were marinated by immersion in marinades based on soy sauce without (SB) or with lactic acid (SBLA) or red wine base without (WB) or with 0.5% v/v oregano essential oil (WBO). For control samples (immersed in saline), a mean increase of 0.9log CFU/cm(2) in total viable counts (TVCs) occurred during the 24h treatment. During marination with WB and SB, mean TVC decreased by 0.7 and 0.3log CFU/cm(2), respectively. The mean decrease in TVC for samples marinated in WBO or SBLA was 1.2log CFU/cm(2). Subsequent storage of beef resulted in a rapid increase of TVC in control samples, to ≥9.5log CFU/cm(2) after 8 days at 5°C or 3 days at 15°C. Significant (P<0.05) microbial growth occurred in marinated samples stored at 5°C. During storage at 15°C TVC increased in only WB samples but the final numbers of 5.9log CFU/cm(2) were significantly lower (P<0.05) than the numbers in the control. Results similar to those for TVC were observed for Pseudomonas spp. All marinades also gave meat with significant lower TBARS values than the controls. There were no significant differences (P>0.05) in the toughness of the marinated samples compared to the control, except for SBLA samples which had significantly higher (P<0.05) shear force values. Marination with soy sauce or red wine marinades can evidently control microbial spoilage and oxidation of meat.

Effect of the ripening time under vacuum and packaging film permeability on processing and quality characteristics of low-fat fermented sausages.

The effect of vacuum ripening of low-fat fermented sausages packaged in films with different permeabilities on their microbiological, physicochemical and sensorial characteristics was studied. High-fat control sausages were produced with 30% initial fat and low-fat sausages with 10% initial fat. The low-fat sausages were separated into: (a) non-packaged (control) and (b) packaged under vacuum on 7th, 12th and 17th day of processing, remaining under vacuum during the ripening period for 21, 16 and 11days, respectively, in three different oxygen (100, 38 and⩽5cm(3)/m(2)/24h/1atm) and water vapour (4.5, <2.5 and 1g/m(2)24h) permeability plastic bags. Vacuum packaging reduced (p<0.05) the weight loss, the hardness and extent of lipid oxidation in the sausages, increased (p<0.05) their lightness, but had no effect (p>0.05) on the redness, compared to the control sausages. Packaging low-fat fermented sausages under vacuum for the last 11days of ripening in packaging film with high permeability increased (p<0.05) the lactic acid bacteria count. The same product packaged in film with medium permeability had a higher (p<0.05) Micrococcaceae count and the same (p>0.05) hardness and overall acceptability as the high-fat control sausages. A ripening time of 11days and the medium packaging film permeability were the most appropriate conditions for the vacuum packaging of low-fat fermented sausages.

Effects of postexsanguination vascular infusion of cattle with a solution of saccharides, sodium chloride, and phosphates or with calcium chloride on quality and sensory traits of steaks and ground beef.

Grain-finished Hereford x Angus steers (n = 36) were assigned to one of three treatmentgroups. Immediately after jugular exsanguination, 12 steers were infused at 10% of live weight via the left carotid artery with a solution developed by MPSC, Inc. (St. Paul, MN) consisting of 98.52% water, 0.97% saccharides, 0.23% sodium chloride, and 0.28% phosphate blend (MPSC); 12 steers were infused at 10% of live weight with 0.30 M CaCl2 (CaCl2); and 12 steers were exsanguinated conventionally and served as noninfused controls (CON). Declines in pH for three muscles were measured. CaCl2-infused carcasses exhibited extensive muscle contraction at the time of cooler entry. Carcasses were graded at 24 h postmortem and fabricated at 48 h postmortem. Longissimus lumborum (LL), semitendinosus (ST), and quadriceps femoris (QF) muscles were removed, vacuum packaged, and stored at 2 degrees C until 14 d postmortem. Then, 2.54-cm-thick steaks were cut from the LL and ST for shear force and sensory evaluations. Ground beef was formulated from the QF to contain 20% fat. Steers infused with MPSC and CaCl2 had 4.0 and 2.3% higher dressing percentage points, respectively, than CON steers. Calcium concentrations of the LL muscle for CaCl2- and MPSC-infused carcasses, as well as the CON carcasses, were 892.0, 158.9, and 216.6 ppm, respectively. For the TB and longissimus thoracis muscles, pH decline was more rapid for CaCl2- and MPSC-infused carcasses than for CON carcasses, but there were no differences in 24-h pH. Warner-Bratzler shear force values were much higher (P < 0.05), and descriptive attribute sensory panel tenderness scores much lower (P < 0.05), for the LL from CaCl2-infused carcasses than for MPSC-infused and CON carcasses. Flavor intensity of the LL of CaCl2-infused carcasses was reduced (P < 0.05); however, overall tenderness and flavor of the ST were unaffected (P > 0.05) by CaCl2 infusion. Beef flavor identification, brown-roasted flavor, and bloody/serumy flavor were lowest and soapy/chemical flavor was highest (P < 0.05) for both freshly cooked and warmed-over LL from CaCl2-infused carcasses. There were no distinct meat quality advantages for infusing cattle with a solution of saccharides, sodium chloride, and phosphates. Infusion with 0.30 M CaCl2 increased dressing percentage, but caused severe muscle contraction early postmortem, decreased LL tenderness markedly, and reduced flavor of LL steaks and ground beef.

Effects of vascular infusion with a solution of saccharides; sodium chloride; phosphates; and vitamins C, E, or both on carcass traits, Warner-Bratzler shear force, and palatability traits of steaks and ground beef.

Three groups of 12 high percentage Charolais steers were slaughtered on three dates. Steers (n = 27) were infused immediately after exsanguination at 10% of BW with a solution containing saccharides, NaCl, and phosphates (MPSC solution; MPSC, Inc., St. Paul, MN) plus either 500 ppm vitamin C (MPSC+C), 500 ppm vitamin E (MPSC+E), or 500 ppm vitamin C plus 500 ppm vitamin E (MPSC+C+E). Noninfused controls (CON) were 9 steers. The longissimus thoracis (LT), semitendinosus (ST), and quadriceps femoris muscles were removed at 48-h postmortem, vacuum-packaged, and aged until 14-d postmortem. Steaks 2.54-cm thick were cut from the LT and ST. The quadriceps was utilized for ground-beef production. Infused steers had higher dressing percentages and heavier heart and liver weights (P < 0.05) than CON. Vascular infusion with vitamins C, E, or C plus E had no effect (P > 0.05) on USDA yield and quality-grade traits, LT and ST Warner-Bratzler shear force, descriptive-attribute traits, and freshly cooked steak flavor-profile traits. Vascular infusion had little effect on the flavor-profile traits of warmed-over steaks. Therefore, the results of our study indicate that vascular infusion with vitamins C, E, or C plus E can increase dressing percentage and organ weights, but have minimal effects on descriptive-attribute and flavor-profile sensory panel ratings.

Effects of vascular infusion with a solution of saccharides, sodium chloride, and phosphates with or without vitamin C on carcass traits, Warner-Bratzler shear force, flavor-profile, and descriptive-attribute characteristics of steaks and ground beef from Charolais cattle.

Two groups of 18 grain-finished steers were utilized. Nine from one group were infused via the carotid artery immediately after jugular vein exsanguination with an aqueous solution containing saccharides, NaCl, and phosphates (MPSC; MPSC, Inc., Eden Prairie, MN, USA). Nine steers served as non-infused controls (CON). An additional 18 steers were infused with either MPSC (n=9) or MPSC plus 1000 ppm vitamin C (MPSC+C, n=9) solutions. Steers infused with MPSC had higher dressing percentages and organ weights than CON steers. Vascular infusion with MPSC had no effects on USDA yield or quality grade traits, descriptive-attribute sensory panel evaluations, or Warner-Bratzler shear force of longissimus lumborum and semitendinosus muscles. Vascular infusion with MPSC resulted in some significant, but inconsistent effects on flavor-profile characteristics of cooked beef. The addition of vitamin C to the MPSC solution did not provide any benefit.

Effects of postexsanguination vascular infusion of cattle with a solution of saccharides, sodium chloride, phosphates, and vitamins C, E, or C+E on meat display-color stability.

Grain-finished, high-percentage Charolais steers (n = 36) were selected for uniformity. Immediately after jugular vein exsanguination, 27 steers were infused at 10% of live weight via the carotid artery with a solution developed by MPSC, Inc. (St. Paul, MN) consisting of 98.52% water, 0.97% saccharides, 0.23% sodium chloride, and 0.28% phosphate blend plus either 500 ppm vitamin C (MPSC+C; n = 9), 500 ppm vitamin E (MPSC+E; n = 9), or 500 ppm vitamin C + 500 ppm vitamin E (MPSC+C+E; n = 9). Uninfused controls (CON) were exsanguinated conventionally. Carcasses were fabricated at 48 h postmortem. Longissimus thoracis (LT), psoas major (PM), and semimembranosus (SM) muscles were removed, vacuum-packaged, and stored at 2 degrees C until 14 d postmortem. Then, steaks 2.54 cm thick were sliced from the three muscles, placed on foam trays, and overwrapped with polyvinyl chloride film. Ground beef (GB) was formulated from the quadriceps femoris to contain 20% fat, mounded into 0.45-kg portions, placed on styrofoam trays, and wrapped with polyvinyl chloride film. Steaks were visually evaluated for uniformity and initial color on display d 0. Instrumental color measurements of L*, a*, b* and trained sensory panel color evaluations were obtained daily for 4 d (PM and GB) or 5 d (LT and SM) of display. No display time x treatment interaction existed for L*, a*, or b* values. The LT from CON cattle had more uniform color (P < 0.05) and was more cherry red than that from all infused cattle on d 0. Visual scores indicated that GB from MPSC+E cattle was more red (P < 0.05) than that from MPSC+C infused cattle throughout display, and GB from MPSC+E cattle was more red (P < 0.05) than that from CON cattle for the last 3 d of display. The vascular infusion solutions generally did not improve color or display-color stability of steaks, but the infusion solution with vitamin E did improve display-color stability of GB.

Novel HPLC analysis of tocopherols, tocotrienols, and cholesterol in tissue.

Tocopherols and tocotrienols are being increasingly recognized to have an important role in the prevention of atherosclerosis. It has been reported that they protect low-density lipoprotein (LDL) and tissues from oxidative stress and that tocotrienols can reduce plasma cholesterol levels. Two isocratic high-performance liquid chromatography (HPLC) methods for simultaneous analysis of tocopherols, tocotrienols, and cholesterol in muscle tissue were developed. Method A involves basic saponification of the sample, but causes losses of the gamma- and delta-homologs of vitamin E. Method B does not involve saponification, thereby protecting the more sensitive homologs. Both permit rapid analysis of multiple samples and neither requires specialized equipment. These methods may provide techniques useful in simultaneous assessment of oxidative stress status (OSS) and cholesterol levels.