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High-quality proteins from farmed fish, including sea bream, represent a cheaper and healthier alternative to proteins from other animals, especially for people affected by chronic diseases. Aquaculture has also the possibility to move towards more sustainable growth and production. Therefore, the present study was designed to evaluate the impact of a starvation period before slaughtering in comparison to full feeding on quality attributes of sea bream fillet focused on their health promoting values. SDS-PAGE, Western blotting and high-resolution MS/MS analyses of the protein profiles showed that in the fillets from starved fish, only the amount of myosin light chains (MLCs) was markedly reduced at slaughter, suggesting their higher susceptibility to proteolysis. In the full feeding samples, MLCs degradation was evident only during storage at 4 °C. Conversely, skeletal alpha-actin fragmentation was similar regardless of the pre-slaughter feeding system. In vitro gastric digestibility of the myosin complex from starved fish fillets was much higher at pH 4, a condition that may occur in drug-treated patients affected by the gastroesophageal reflux disease (GERD). Using UHPLC–MS/MS, ACE-inhibitor gastric-resistant bioactive peptides potentially coming from MLCs (VF, MF) were found in all the digested samples, with one of these peptides (MF) being present in larger amount in the starved samples. Pre-slaughter starvation, other than decreases the environmental impact of fish aquaculture, is an effective tool in obtaining good-quality sea bream fillets that provide potential health benefits for hypertensive and GERD consumers. [ABSTRACT FROM AUTHOR]

Using Western blotting and mass spectrometry we investigated the changes in trout muscle proteins as affected by pre-slaughter nutrient supply practices, including starvation and feed restriction, in comparison to full feeding. A number of fillet quality attributes were also analyzed. During cold storage, fillet firmness was not influenced by the feeding practices, while the initial pH was higher in the treated trout. The early appearance of an alpha-actin 26 kDa-fragment and the detection of enigma protein were both signs of impaired muscle integrity, observed only in the restricted conditions, where water holding capacity was initially lower. The detection of reticulon involved in authophagy and the early finding of apolipoprotein A-I-1 fragments in these restricted samples was consistent with their early degradation in comparison to full ration controls. Since specific protein changes reflected differences in feed management, the use of selected muscle proteins as sensitive indicators of fillet quality is proposed. [ABSTRACT FROM AUTHOR]

Proteomics is the approach of choice to study the fate of specific proteins, and it is very useful in identifying quality molecular markers. A combination of immunochemical and mass spectrometry analysis was used to assess the occurrence of proteolytic changes of actin and myosin heavy chain (MHC) proteins in pig biceps femoris skeletal muscle during processing of three Italian PDO dry-cured hams. Early post-mortem muscle displayed low levels of actin and myosin fragments. In spite of a high proteolysis index and the presence of active cathepsin D until the final ripening phase, during dry-cured ham processing, very low actin proteolysis and no generation of fragments from α-skeletal muscle isoform were found, while the identified fragments derived mainly from the cardiac actin isoform. On the other hand, MHC showed a remarkable degradation of its catalytic head, generating a C-terminal 135-kDa fragment. Based on its ability to interact with actin in vitro, this MHC fragment might have a role in stabilisation of actin. In conclusion, these results suggest that maintenance of skeletal muscle α-actin could reflect limited dismantling of the sarcomeric structure and be a useful marker to monitor the events that result in the typical texture of dry-cured ham. [ABSTRACT FROM AUTHOR]

Qualitative and quantitative methods for the analysis of intact phytosteryl/phytostanyl esters in enriched dairy products with substantial amounts of protein and fat were established. Lipids were extracted after acid digestion in order to achieve a complete extraction of the esters. The extracted lipids were separated via liquid chromatography on a normal phase, and the fraction containing the phytosteryl/phytostanyl esters was subsequently transferred on-line and analyzed by means of capillary gas chromatography. The applicability of the method was demonstrated for the analysis of intact phytosteryl/phytostanyl fatty acid esters in enriched yogurt, cheese-based spread, and milk. The approach enables the determination of individual phytosteryl/phytostanyl esters as well as of their total contents and provides detailed information on the distributions of esterified phytosterols/phytostanols and fatty acids. The employed approach complements the existing GC-based methods for the analysis of phytosteryl/phytostanyl esters in low-fat and fat-based products and thus creates a base for authenticity assessments of these types of novel foods. [ABSTRACT FROM AUTHOR]

An evaluation of the potential allergenicity of different tomato ecotypes is reported. Twelve tomato ecotypes were assessed through a proteomic approach, using pools of sera of allergic patients from two different regions (Emilia Romagna in Northern Italy and Campania in Southern Italy), in order to identify the major allergens and evaluate differences in IgE binding properties of the tomato cultivars. Pooled sera of allergic people from Emilia Romagna showed as the main allergen a suberization-associated anionic peroxidase, whereas pooled sera of allergic patients from Campania were mostly reactive to profilin. The two proteins were identified through a proteomic approach based on the use of high-resolution mass spectrometric techniques. Quite interestingly, in some cases, several ecotypes showed a less reactivity toward patients' sera than other, potentially indicating the possibility to identify ipoallergenic varieties. Anyway, the allergenic pattern response to tomatoes was serum-specific, indicating that the allergenic properties of different tomato ecotypes are defined by the specific proteins to which the patient is sensitized, a strong indication that ipoallergenicity of the different ecotypes is possible, but mostly related to the individual susceptibility. [ABSTRACT FROM AUTHOR]