M. Caroprese

Combined effect of MAP and active compounds on fresh blue fish burger

The combined effects of three essential oils [thymol, lemon extract and grapefruit seed extract (GFSE)] and modified atmosphere packaging conditions (MAP) on quality retention of blue fish burgers was studied and discussed. In particular, samples were packaged in air and in three different gas mix compositions: 30:40:30 O(2):CO(2):N(2), 50:50 O(2):CO(2) and 5:95 O(2):CO(2). During a 28-day storage period at 4 degrees C, the nutritional, microbiological and sensorial quality of the packed products was assessed. The potential development of biogenic amines was also evaluated. The obtained results highlight the possibility to improve the microbial quality of blue fish burgers by using very small amount of thymol (110ppm), GFSE (100ppm) and lemon extract (120ppm) in combination with MAP. Based primarily on microbiological results, the combined use of the tested natural preservatives and a packaging system characterized by a high CO(2)-concentration, was able to guarantee the microbial acceptability of fish burgers until the 28th day of storage at 4 degrees C. On the other hand, results from sensory analyses showed that sensorial quality was the sub-index that limited the burgers shelf life (to about 22-23days), even if the proposed strategy was also effective in minimizing the sensory quality loss of the product having no effect on its nutritional quality.

Lambs prevented from suckling their mothers display behavioral, immune and endocrine disturbances.

The aim of the experiment was to assess the effects of either maternal deprivation or prevented suckling on lambs. Thirty Comisana lambs were assigned to a control dam-suckled group (DS) and two test groups of 10 each. Test lambs were maintained with their mothers 24 to 30 h after parturition and subsequently offered ewe milk from buckets: EM lambs were separated from their mothers, while EM+D animals were reared with their dams but suckling was denied by covering ewe udders with juta bags. Behavioral, immune and cortisol responses of lambs were assessed throughout the experiment. EM+D lambs spent less time (P<.001) on investigative behavior compared to the two other groups. When isolated in a novel environment, EM+D lambs exhibited a shorter duration of movement (P<.01) and a longer latency time compared to DS and EM lambs (P<.001 and P<.05, respectively) as well as a higher number of bleats (P<.01) than EM lambs. EM+D lambs also displayed higher (P<.001) plasma cortisol levels than the other two groups when isolated at 4 days of age. When subjected to discrimination tests, EM+D lambs spent less time near their companions (P<.01) than EM lambs and took a longer time to reach their pen mates (P<.01) than DS and EM lambs. EM+D lambs displayed reduced growth (P<.001) compared to DS animals during the 0-7 and 8-14-day periods. We conclude that frustration arising from maternal feeding deprivation results in altered endocrine and behavioral responses and reduced growth suggesting emotional disturbances of lambs.

Flaxseed supplementation improves fatty acid profile of cow milk.

The objective of the study was to determine the effects of adding flaxseed or fish oil to the diet on the milk fatty acid profile of cows. The experiment was conducted in the summer of 2006 and involved 24 Friesian cows that were divided into 3 groups of 8 animals according to different type of fat supplementation: a traditional diet with no fat supplementation, a diet supplemented with whole flaxseed, and a diet supplemented with fish oil. Results suggested that whole flaxseed supplementation positively affects the milk fatty acid profile during summer. In particular, milk from cows receiving flaxseed supplementation showed a decrease in saturated fatty acid, an increase in monounsaturated fatty acid, and, together with the milk from fish oil-supplemented cows, an increase in polyunsaturated fatty acid content compared with milk from control cows. As expected, both fish oil and flaxseed supplementation increased the content of n-3 polyunsaturated fatty acids in milk fat. The increased dietary intake of C18:3 in flaxseed-supplemented cows resulted in increased levels of milk C18:1 trans-11 and increased conjugated linoleic acid C18:2 cis-9,trans-11 by Delta(9)-desaturase activity. Milk from flaxseed-supplemented cows together with the high conjugated linoleic acid content was characterized by low atherogenic and thrombogenic indices, suggesting that its use has less detrimental effects concerning the atherosclerosis and coronary thrombosis risk associated with the consumption of milk and dairy products. In conclusion, flaxseed supplementation improves composition and nutritional properties of milk from cows milked during times of high ambient temperature.

Composition and sensory profiling of probiotic Scamorza ewe milk cheese

The present study aimed to assess the effect of the addition of different usually recognized as probiotic bacterial strains on chemical composition and sensory properties of Scamorza cheese manufactured from ewe milk. To define the sensory profile of Scamorza cheese, a qualitative and quantitative reference frame specific for a pasta filata cheese was constructed. According to the presence of probiotic bacteria, cheeses were denoted S-BB for Scamorza cheese made using a mix of Bifidobacterium longum 46 and Bifidobacterium lactis BB-12, and S-LA for Scamorza cheese made using Lactobacillus acidophilus LA-5. The designation for control Scamorza cheese was S-CO. Analyses were performed at 15d of ripening. The moisture content of Scamorza ewe milk cheese ranged between 44.61 and 47.16% (wt/wt), showing higher values in S-CO and S-BB cheeses than in S-LA cheese; the fat percentage ranged between 25.43 and 28.68% (wt/wt), showing higher value in S-LA cheese. The NaCl percentage in Scamorza cheese from ewe milk was 1.75 ± 0.04% (wt/wt). Protein and casein percentages were the highest in Scamorza cheese containing a mix of bifidobacteria; also, the percentage of the proteose-peptone fraction showed the highest value in S-BB, highlighting the major proteolysis carried out by enzymes associated with B. longum and B. lactis strains. Texture and appearance attributes were able to differentiate probiotic bacteria-added cheeses from the untreated control product. In particular, S-BB and S-LA Scamorza cheeses showed higher color uniformity compared with S-CO cheese. Furthermore, the control cheese showed higher yellowness and lower structure uniformity than S-BB. The control product was less creamy and grainy than S-BB; conversely, the inclusion of probiotics into the cheese determined lower adhesivity and friability in S-BB and S-LA than in S-CO. This study allowed the definition of the principal composition and sensory properties of Scamorza ewe milk cheese. The specific quantitative vocabulary for sensory analysis and reference frame for assessor training also established in this study should be implemented to systematically monitor the quality of this new typology of ewe milk cheese.

Relationship between cortisol response to stress and behavior, immune profile, and production performance of dairy ewes.

The existence of a relationship between cortisol levels, after an acute stress, and behavioral activities, immunological profile, and production performance in sheep was studied. An initial flock of 30 Comisana ewes was involved in the experiment, and each of the 30 ewes was individually subjected to an isolation test in a novel environment. Subsequently, from the initial flock, 2 groups of 8 Comisana ewes were each retrospectively selected, and the animals were divided, according to their cortisol concentration 10 min after the isolation test, into high cortisol (HC) ewes, having a peak of cortisol concentration >90 ng/mL (average: 119.3 ng/mL +/- 11.8), and low cortisol (LC) ewes having a peak of cortisol concentration <80 ng/mL (average: 52.4+/-11.8). During the isolation test, the behavior of each animal was video-recorded and behavioral activities were registered. Blood samples were collected before the isolation test, immediately after the test (10 min), and at 60, 120, 300 min, 24 h, and 48 h after the test to evaluate percentages of T-helper (CD4(+)) and T-cytotoxic (CD8(+)) cells, CD4(+)/CD8(+) ratio, and IL-1beta and IL-6 levels. The ewes were milked for 3 d after the isolation test to determine cortisol levels and IL-1beta and IL-6 concentrations in whey. Milk yield was recorded at each milking, and milk samples were analyzed for pH, nutritional parameters, renneting properties, and somatic cell count. During the isolation test, HC ewes exhibited a shorter duration of movement and fewer bleats than LC ewes. The average plasma IL-1beta concentration was higher in HC than in LC ewes. The average whey IL-1beta and IL-6 concentrations were higher in whey from HC ewes than in LC ewes. A positive correlation emerged between plasma and whey IL-1beta concentrations. The average CD4(+)/CD8(+) ratio in blood was lower in HC than in LC ewes. Time from isolation affected the CD4(+)/CD8(+) ratio: at 120 min, the CD4(+)/CD8(+) ratio increased compared with that at 10 min after isolation and then decreased until 300 min after isolation. On average, ewes with low cortisol concentrations showed higher milk production and lower SCC than ewes with high cortisol concentrations. Results suggest that plasma cortisol concentration is connected to the behavioral response and immune competence of dairy ewes and cytokine concentrations. Both whey IL-1beta and IL-6 can be considered reliable indicators of the magnitude of hypothalamic-pituitary-adrenal axis activation. The stress-induced changes in CD4(+)/CD8(+) ratio are critical for controlling disease incidence and planning appropriate vaccination programs. High reactivity of the hypothalamic-pituitary-adrenal axis is also associated with a reduction in milk production and an increased predisposition to develop intramammary inflammatory processes.

Physicochemical properties of Scamorza ewe milk cheese manufactured with different probiotic cultures

The present study was undertaken to produce functional Scamorza cheese from Gentile di Puglia ewe milk by incorporating probiotic strains into the cheese matrix and to evaluate the physicochemical characteristics of Scamorza ewe milk cheese. Gentile di Puglia ewe bulk milk was used for Scamorza cheese production. Cheeses were denoted S-CO for control Scamorza cheese, S-BB for Scamorza cheese made using a mix of Bifidobacterium longum and Bifidobacterium lactis, and S-LA for Scamorza cheese made using Lactobacillus acidophilus as probiotic strain. Cheeses were analyzed at 1, 7, and 15 d of ripening. Probiotic cell recovery in cheese was 7.55 ± 0.07 log10 cfu/g and 9.09 ± 0.04 log10 cfu/g in S-LA and S-BB cheese, respectively; probiotic cheeses also displayed the highest levels of lactic microflora. Reverse-phase HPLC chromatograms of the water-soluble nitrogen fraction showed a more complex profile in S-BB, with distinctive peaks in the early-eluting zone. The matured Scamorza cheese containing the mix of B. longum and B. lactis was characterized by significantly higher levels of Gln, Ser, Arg, Ile, and Leu, whereas cheese containing Lb. acidophilus was characterized by higher levels of Tyr and Met. Total FFA content was the highest in S-LA, intermediate in S-BB, and the lowest in S-CO cheese; in particular, Scamorza cheese containing Lb. acidophilus showed the highest level of vaccenic acid, oleic acid, and total conjugated linoleic acid. Probiotic bacteria survived through the technological phases of pasta filata cheese production, maintained their specific metabolic pathways, and conferred functional properties to Scamorza ewe milk cheese.

Effect of solar radiation and flaxseed supplementation on milk production and fatty acid profile of lactating ewes under high ambient temperature

The objectives of this study were to evaluate the effects of protection from solar radiation and whole flaxseed supplementation on milk yield and milk fatty acid profile in lactating ewes exposed to high ambient temperature. The experiment was conducted during summer and involved 40 ewes divided into 4 groups. The ewes were either exposed (not offered shade) or protected from solar radiation (offered shade). For each solar radiation treatment, ewes were supplemented with whole flaxseed or not. Milk samples from each ewe were collected at the morning and afternoon milking every week, and analyzed for pH, total protein, casein, fat, and lactose content, somatic cell count, and renneting parameters (clotting time, rate of clot formation, and clot firmness after 30 min). At the beginning of the experiment, and then at d 23 and 44, milk samples were analyzed for milk fatty acids using gas chromatography. Flaxseed supplementation significantly increased milk yield, fat, protein, and casein yields, and somatic cell count, and increased fat and lactose contents of milk. A decrease of saturated fatty acids from C6:0 to C16:0 and an increase of C18:1 trans-11 and C18:2 cis-9,trans-11 was observed in milk from flaxseed-supplemented ewes. Flaxseed supplementation decreased saturated fatty acids content and increased total monounsaturated fatty acids content, the total content of isomers of conjugated linoleic acid, and polyunsaturated fatty acids content in milk. Flaxseed also increased the α-linolenic acid content of milk. As a result, milk from supplemented groups showed an increase in n-3 fatty acid content. Flaxseed supplementation decreased short-chain and medium-chain fatty acids, and increased long-chain fatty acid content of milk. On average, flaxseed supplementation increased the C18:2 cis-9,trans-11/C18:1 trans-11 Δ(9)-desaturase index starting from d 23 of the experiment, in correspondence with the highest C18:2 cis-9,trans-11 content of milk from flaxseed-supplemented ewes. Flaxseed decreased atherogenic and thrombogenic indices of milk. Protection from solar radiation during summer did not improve yield and composition of ewe milk. Nevertheless, milk from ewes exposed to solar radiation showed decreased long-chain fatty acid and polyunsaturated fatty acids contents, and in particular, decreased vaccenic acid, rumenic acid, and total conjugated linoleic acid contents.

Role of endogenous enzymes in proteolysis of sheep milk

The aim of the present study was to determine the role of milk endogenous proteolytic enzymes in sheep milk cheesemaking ability during lactation. Plasmin, plasminogen, and plasminogen activator in ewe bulk milk were not significantly affected by stage of lactation, probably because of the good health of the ewe udders throughout lactation as indicated by somatic cell count, which never exceeded 600,000 cells/mL. Elastase content increased significantly during lactation, whereas cathepsin showed the greatest content in mid lactation. Early and mid lactation milk showed impaired renneting parameter compared with late lactation milk, probably because of greater alpha-casein degradation, brought about by cathepsin, and lesser fat and casein (CN) milk contents. Changes in macrophage and neutrophil levels in ewe bulk milk during lactation were also investigated. Macrophages minimally contributed to leukocyte cell count in milk and had the greatest levels at the beginning of lactation. An opposite trend was recorded for polymorphonuclear neutrophilic leucocytes (PMNL) that increased throughout lactation, showing the greatest value in late lactation. Urea-PAGE of sodium caseinate (NaCN) incubated with isolated and concentrated PMNL at 37 degrees C after 48 h at pH 8 showed massive casein degradation that could be ascribed to proteases yielded by PMNL. The increase of PMNL percentage and elastase content in milk, despite the relatively low SCC, suggests that PMNL and elastase underwent a physiological increase associated to the remodeling of mammary gland in late lactation.

Biochemical patterns in ovine cheese: Influence of probiotic strains

This study was undertaken to evaluate the effect of lamb rennet paste containing probiotic strains on proteolysis, lipolysis, and glycolysis of ovine cheese manufactured with starter cultures. Cheeses included control cheese made with rennet paste, cheese made with rennet paste containing Lactobacillus acidophilus culture (LA-5), and cheese made with rennet paste containing a mix of Bifidobacterium lactis (BB-12) and Bifidobacterium longum (BB-46). Cheeses were sampled at 1, 7, 15, and 30 d of ripening. Starter cultures coupled with probiotics strains contained in rennet paste affected the acidification and coagulation phases leading to the lowest pH in curd and cheese containing probiotics during ripening. As consequence, maturing cheese profiles were different among cheese treatments. Cheeses produced using rennet paste containing probiotics displayed higher percentages of alpha(S1)-I-casein fraction than traditional cheese up to 15 d of ripening. This result could be an outcome of the greater hydrolysis of alpha-casein fraction, attributed to higher activity of the residual chymosin. Further evidence for this trend is available in chromatograms of water-soluble nitrogen fractions, which indicated a more complex profile in cheeses made using lamb paste containing probiotics versus traditional cheese. Differences can be observed for the peaks eluted in the highly hydrophobic zone being higher in cheeses containing probiotics. The proteolytic activity of probiotic bacteria led to increased accumulation of free amino acids. Their concentrations in cheese made with rennet paste containing Lb. acidophilus culture and cheese made with rennet paste containing a mix of B. lactis and B. longum were approximately 2.5 and 3.0 times higher, respectively, than in traditional cheese. Principal component analysis showed a more intense lipolysis in terms of both free fatty acids and conjugated linoleic acid content in probiotic cheeses; in particular, the lipolytic pattern of cheeses containing Lb. acidophilus is distinguished from the other cheeses on the basis of highest content of health-promoting molecules. The metabolic activity of the cheese microflora was also monitored by measuring acetic, lactic, and citric acids during cheese ripening. Cheese acceptability was expressed for color, smell, taste, and texture perceived during cheese consumption. Use of probiotics in trial cheeses did not adversely affect preference or acceptability; in fact, panelists scored probiotic cheeses higher in preference over traditional cheese, albeit not significantly.

Changes in meat quality traits and sarcoplasmic proteins during aging in three different cattle breeds.

The effects of breed and aging time (1, 7, 14, 21d) were evaluated on physical meat properties and on sarcoplasmic protein changes in 24 young bulls from Romagnola×Podolian, Podolian and Friesian breeds. Aging affects lightness showing an increase in all breeds while changes in redness varied according to the breed. Podolian breed showed meat with the darkest and the reddest color and the lowest drip loss compared to the other breeds. Extending aging to 21d reduced drip loss from meat. SDS-PAGE and 2DE showed that many changes in the sarcoplasmic proteins occurred among breeds and during aging. During post-mortem some sarcoplasmic proteins decline in intensity after 21d highlighting that they were susceptible to aging. Protein identification and western blotting showed the presence of myosin light chains, Troponin T and tropomyosin proteins during aging, suggesting a degradation of myofibers and a more intense proteolysis especially in the Podolian breed.