Pectin content and composition from different food waste streams

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Extraction, identification and semi-quantification of oligopeptides in cocoa beans

Peptides and amino acids generated during cocoa bean fermentation are known to be the most important precursors for the development of cocoa aroma. Although cocoa fermentation and aroma development have been extensively studied, the cocoa oligopeptide fraction is under-investigated. In particular, the identification of specific peptide sequences and the quantification of cocoa peptides are scarce in the literature. The aim of this study was to investigate the presence of oligopeptides in fermented cocoa beans. Peptides were analysed by reversed phase LC/ESI-MS and LC/ESI-MS/MS, and the molecular masses of 44 different peptides were obtained by analysing the mass spectra associated with the most intense chromatographic peaks. Peptides were identified based on the exact molecular masses, mass fragmentation patterns and by comparison with vicilin and 21 kDa cocoa seed protein sequences. Semi-quantitative data on peptide presence in fermented cocoa samples of different geographic origin, different fermentation levels and on roasted products were also provided

Proteolytic resistance of actin but not of myosin heavy chain during processing of Italian PDO (protected designation of origin) dry-cured hams

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 drycured 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 \u3b1-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 \u3b1-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

Common Wheat Determination in Durum Wheat Samples Through LC/MS Analysis of Gluten Peptides

A method to detect the presence of common wheat in durum wheat flour samples was developed and tested. Flour samples, or ground wheat samples, were digested by pepsin and chymotrypsin, and the peptide mixture obtained was analyzed by LC/ESI-MS and LC/ESI-MS/MS, which led to the identification of two marker peptides. One peptide was coded only in the DD genome, and thus present only in common wheat; the second was present in all wheat samples (both common and durum), so it was used as marker of the total wheat content. The ratio of the chromatographic areas of these two peptides, as determined by LC/ESI-MS, was related to the proportion of common wheat in the sample using a calibration curve that was constructed with standards of known composition. The proportions of common wheat in samples obtained by mixing different common and durum wheat varieties were accurately determined by this method. Finally, the method was applied in a survey of several durum wheat flour brands present on the Italian market. The results of the survey revealed that contamination of durum wheat flour with common wheat is commonplace

TECNOLOGIE A PNA PER LA TRACCIABILITÀ NELLA FILIERA DEL POMODORO

I prodotti alimentari tutelati dai marchi di qualità sono sempre più spesso oggetto di tentativi di imitazione che danneggiano il settore delle produzioni ‘made in Italy’. In tale contesto lo sviluppo di sistemi di tracciabilità molecolari per monitorare i diversi stadi delle filiere agroalimentari assume un ruolo importante nel garantire l’autenticità delle materie prime impiegate e verificarne la corrispondenza nel prodotto finito. Nel presente studio sonde chirali di PNA (acidi peptido nucleici), analoghi sintetici del DNA, sono state progettate per l’identificazione e la discriminazione di sette cultivar di pomodoro, utilizzate preferenzialmente nell’industria conserviera del sud Italia, mediante il riconoscimento selettivo di mutazioni SNP (polimorfismi a singolo nucleotide) caratteristiche. A tale scopo le sonde a PNA sintetizzate sono state utilizzate sia per testare la fattibilità di un sistema microarray, mediante ibridazione su superficie con oligonucleotidi sintetici simulanti le sequenze geniche contenenti la mutazione. I risultati ottenuti finora hanno dimostrato la capacità dei PNA chirali di riconoscere perfettamente su superficie le sequenze di DNA complementari e di distinguere in maniera altamente specifica sequenze contenti mismatches in corrispondenza dello SNP cercato. Le stesse sonde sono anche state utilizzate in sistemi di PCR clamping, in cui si sono rivelate idonee per bloccare, in maniera altamente specifica, l’amplificazione del DNA dei genotipi di pomodoro recanti la mutazione allo stato omozigote, rappresentando quindi un valido strumento di fingerprinting molecolare delle cultivar analizzate

SCREENING DI 12 ECOTIPI DI POMODORO (LYCOPERSICON ESCULENTUM) PER LA DETERMINAZIONE DELLE PROPRIETÀ ALLERGENICHE

Il pomodoro è considerato uno degli alimenti essenziali della dieta mediterranea grazie al suo elevato contenuto in antiossidanti a cui si associano effetti antitumorali e riduzione del rischio di malattie cardiovascolari. I casi di allergie al pomodoro, seppur rari, sono tuttavia in continuo aumento, rappresentando una potenziale minaccia per la salute dei consumatori. Seppur non contemplato nella direttiva UE che regolamenta l’etichettatura alimentare, il pomodoro può essere quindi considerato uno dei principali “allergeni emergenti”. Una potenziale soluzione a questo problema potrebbe essere rappresentata dall’utilizzo di varietà che manifestino una ridotta espressione delle proteine allergeniche. A tale scopo, utilizzando sieri di pazienti allergici di diversa provenienza (zona emiliana e zona campana), è stato effettuato, mediante approccio proteomico, lo screening di 12 ecotipi di pomodoro, al fine di identificare i principali allergeni coinvolti e valutare eventuali differenze nelle proprietà allergeniche delle cultivar considerate. Le analisi condotte finora hanno consentito l’identificazione di differenti proteine reattive, riportate in letteratura come noti allergeni. È emerso, inoltre, che i profili allergenici identificati sono altamente siero-specifici, per cui la capacità di ogni ecotipo di indurre o meno una risposta allergica deve essere valutata in riferimento alla specifica proteina allergenica a cui ogni singolo paziente è sensibilizzato

Food wastes from agrifood industry as possible sources of proteins: A detailed molecular view on the composition of the nitrogen fraction, amino acid profile and racemisation degree of 39 food waste streams

The nitrogen fraction of 39 food waste streams was characterized by Kjeldahl analysis, amino acid analysis, protein analysis and racemization degree, for assessing their potential for further valorization. For every waste streams the specific nitrogen-to-protein conversion factor was calculated, allowing to assess the accurate protein content. The results indicated which streams are most rich in relevant proteins (all wastes of dairy origin, beer yeast, malted barley germs, brewing cake, rapeseed press cake, sea buckthorn spent pulp, leek leaves, parsley waste, pumpkin kernel cake, and mushroom waste), which ones have valuable proteins, but in too little amount, and also which ones are rich in proteins, but of low nutritional value. Specific data also indicated, for every waste stream, its possible use for supplementing specific amino acids. To date, this represents the most complete characterization with homogeneous methodologies of the nitrogen fraction in food waste streams ever reported in the literature and outlines in unprecedented molecular details the potentialities and the limitations of many waste streams to be used as source of proteins