Milk quality of Italian Mediterranean Buffalo as affected by Temperature-Humidity Index during late spring and summer.

Eighteen Italian Mediterranean buffalo cows were subjected to fortnightly milk sampling from May to July 2022. Air temperature and relative humidity were monitored throughout the trial; temperature-humidity index (THI) was calculated and ranged from 69 to 79 so that 3 classes were set to study the effect of different THI on milk quality: THI less than 72 - THI < 72; THI ranging from 72 to 76 THI72-76, and THI over 76 - THI > 76. Individual milk samples from buffalo cows were analyzed for milk composition and coagulation traits, fatty acid and amino-acid composition, enzymatic and mineral profile. The THI > 76 class registered the highest lactose content and poorer milk clot characteristics in comparison with THI < 72. Exposure to THI over 76 resulted in increased contents of saturated and short- chain fatty acids in milk as well as in the highest values of atherogenic and thrombogenic indexes and the lowest essential amino-acid content. Moreover, the lowest value of Calcium, Copper and Selenium contents were found in the milk of buffalo cows exposed to THI over 72. Results confirm that Italian Mediterranean buffalo expresses a good level of thermo-tolerance, even though exposure to daily THI over 76 has a deleterious effect on some nutritional and technological properties of milk.

Effects of whole linseed supplementation and treatment duration on fatty acid profile and endogenous bioactive compounds of beef muscle.

Diet supplementation with oilseeds is known to improve the fatty acid profile of meat, but few studies have been carried out to determine the time required for the incorporation of a significant quantity of n-3 polyunsaturated fatty acids (PUFA) into meat from steers. Therefore, the present study aimed to assess the effects of linseed supplementation and feeding duration on the fatty acid profile, cholesterol and bioactive compounds of bovine meat. In total, 54 Friesian steers were randomly allocated during the finishing period into six experimental treatments following a 2×3 factorial design. The six treatments consisted of two diets, the control diet (CO) with no supplemental fat and the linseed diet (LS) containing 10% whole linseed, fed 40, 75 or 120 days before slaughter. At the end of each finishing period, steers from the CO and LS groups were slaughtered. After 8 days of ageing chemical analysis, the fatty acid profile, cholesterol content and bioactive compounds were determined from the longissimus thoracis muscle. Including linseed in the diet increased the content of monounsaturated fatty acids, CLA and n-3 PUFA, and reduced the proportion of saturated fatty acids and n-6 PUFA. The percentage of myristic fatty acid increased with the duration of feeding, regardless of diet and a decrease in PUFA and n-6 PUFA was observed in the CO and LS diets, respectively. Furthermore, meat from steers fed linseed showed an increased percentage of n-3 PUFA, linolenic acid, and EPA from 40 to 75 days of feeding, whereas vaccenic acid, CLA 9c,11t, and total CLA increased from 40 and 75 days but declined at 120 days. Beef from the linseed group had a higher content of bioactive substances such as creatine, carnosine and anserine than beef from the control group. The duration of feeding significantly affected the creatine concentrations, with an increase in the LS group from 40 to 75 days of feeding. Feeding linseed did not modify the cholesterol content, on average and the lowest cholesterol content was found in meat after 75 days of linseed administration. This study demonstrates that a short-term diet manipulation is sufficient to improve the nutritional properties of meat, including n-3 PUFA and bioactive compounds.

Identification of peptides in functional Scamorza ovine milk cheese.

Ovine bulk milk was used to produce Scamorza cheese with probiotics: either a mix of Bifidobacterium longum and Bifidobacterium lactis or Lactobacillus acidophilus as the probiotic strains. Peptides obtained from reverse phase-HPLC water-soluble extract of Scamorza cheeses were analyzed using a quadrupole time-of-flight liquid chromatography-mass spectrometry system. Identified fragments were derived from casein hydrolysis or probiotic bacterial enzymes; some of the fragments showed encrypted peptide sequences that shared structural homology with previously described bioactive peptides in ovine milk and dairy products. Bifidobacterium longum and B. lactis showed greater proteolytic potential both in terms of level of pH 4.6 water-soluble nitrogen extract and ability to generate peptides with potential biofunctionality. Fragments deriving from microbial enzymes may be regarded as tracing fragments useful for monitoring probiotic activity in functional Scamorza cheese.

Proteolytic changes of myofibrillar proteins in Podolian meat during aging: focusing on tenderness.

The aim of this study was to understand the relationship between changes in postmortem degradation of myofibrillar proteins and tenderness development in 3 different muscles from 10 Podolian young bulls aged 1, 7, 14, and 21 d. Psoas major (PM), longissimus dorsi (LD), and semitendinosus muscle () were removed from each half carcass 24 h postmortem. Meat chemical composition, Warner-Bratzler shear force (WBSF), myofibril fragmentation index (MFI), total collagen content, and changes in myofibrillar proteins were estimated in triplicate at each aging time. A significant muscle effect was found on meat chemical composition. Semitendinosus muscle showed the lowest intramuscular fat percentage ( < 0.01) and the highest total collagen content ( < 0.01) with respect to LD and PM. Warner-Bratzler shear force decreased during aging in all muscles ( < 0.001), and semitendinosus was the toughest muscle whereas PM was the most tender ( < 0.001). Myofibril fragmentation index significantly increased ( < 0.001) in LD and PM meat throughout aging time whereas in semitendinosus it increased from 14 d of aging. Proteolysis was investigated by SDS-PAGE, western blotting, and 2-dimensional electrophoresis. Throughout postmortem aging, some structural proteins changed in intensity in all muscles analyzed. The blotting profile highlighted that desmin and troponin-T (TnT) bands were affected by both muscle and aging effects. Desmin degradation was more intense and faster in LD muscle than in semitendinosus and PM muscles. A progressive increase of the degraded isoforms of TnT (33 and 30 kDa polypeptides) was found during aging in LD, while, in PM these bands appeared earlier showing a greater intensity from 1 d. During aging, 2-dimensional gel electrophoresis (2DE) image analyses results showed a significant increase of the total number of spots reaching the highest value in the LD muscle at 21 d of aging ( < 0.01). Proteins separation also revealed differences in the spot number and expression patterns of myosin light chain (MLC) isoforms among muscles. A principal components analysis applied to meat chemical composition, tenderness, and myofibrillar proteins accounted for approximately 96.09% of total variance. Data highlight that aging affects the meat tenderness and proteolysis with different intensities in each muscle. These results provide knowledge about the tenderness mechanism in different muscles from a rustic breed and could be useful for the development of muscle specific strategies for improving the quality and value in different commercial cuts.

Nutritional properties and consumer evaluation of donkey bresaola and salami: comparison with conventional products.

Nutritional properties and consumer evaluation were performed in bresaola and salami from donkey meat compared with respective conventional products. Donkey bresaola and salami showed higher content of protein and lower content of fat than beef bresaola and pork salami. Significant differences in the unsaturation level of fatty acids were found. Particularly, donkey meat products showed lower saturated fatty acids, higher polyunsatured fatty acid content and better nutritional indices than conventional beef bresaola and pork salami. Furthermore, donkey meat products, especially bresaola, showed the highest content of essential amino acids. Both donkey meat products resulted to be more tender than conventional products, in addition donkey bresaola showed also higher consumer acceptability. Our investigation demonstrates the possibility of processing donkey meat into products comparable to traditional ones with a high nutritional value.

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.

Proteolytic pattern of myofibrillar protein and meat tenderness as affected by breed and aging time.

The effects of breed and aging time (1, 7, 14, 21 days) were evaluated on meat tenderness and on proteolysis in 24 young bulls from Romagnola×Podolian crossbreed, Podolian and Friesian breed. Shear force decreased with aging in all breeds and showed the highest values at 1 and 7 days in Podolian meat. Myofibrillar fragmentation index significantly increased in Podolian meat throughout aging whereas in Friesian and in Crossbreed meat it increased only in the first week. Proteolysis was investigated by SDS-PAGE and 2-dimensional electrophoresis showing a different quantity and expression profile of myofibrillar proteins among breeds. In all breeds a decrease of troponin-T and an increase of troponin-T derived polypeptides during aging were observed. The highest decrease of troponin-T together with the presence of fragments of MHC in Podolian meat during aging was an outcome of a more extensive proteolysis in this breed. Data suggest that tenderness and proteolytic changes during aging are related to animal's breed.

Effect of low voltage electrical stimulation on protein and quality changes in bovine muscles during postmortem aging.

This experiment was conducted to determine the influence of low voltage electrical stimulation (ES) on the tenderness development of beef round muscles. Eight steers were slaughtered, and ES applied to one side of each carcass within 90 min of exsanguination. Steaks from M. longissimus dorsi, semimembranosus, adductor, and gracilis were vacuum packaged and aged at 4 °C for 9 d. Star probe, sensory evaluation, Western blot assays of troponin-T and µ-calpain autolysis and 2D-DIGE were conducted. ES resulted in accelerated (P<0.05) pH decline of the longissimus in the first 24h postmortem. ES did not influence (P>0.05) proteolysis and tenderness, but did alter the predominance of metabolic proteins in the soluble fraction of muscle. Aging for 9 d improved tenderness (P<0.05). The data confirmed that low voltage ES at 90 min of exsanguination had no effect on proteolysis and tenderness development in the longissimus dorsi, semimembranosus, adductor or gracilis in beef.