1,721,226 research outputs found
A mass spectrometry approach to dairy science
No full textBovine milk is a source of an array of (un)known (bioactive) compounds from a variety of molecular and chemical classes. Because of a such complex food matrix, accurate and sensitive analytical approaches are needed to identify newly formed molecules (e.g. bioactive milk non-nutrients or xenobiotics), to recognize chemical and enzymatic modifications which known milk components undergo upon processing, storage and in vitro digestion. In this perspective, tailored sample preparation followed by liquid chromatography/high resolution mass spectrometry (LC/HR-MS) represents a powerful analytical tool to solve some scientific issues in dairy sector. In this presentation, some of the current applications of MS in dairy science will be discussed with special regard to characterization of novel functional/(bio)active milk compounds [1], reliable identification of dairy markers (e.g. studying post-translational modifications [2], proteolytic phenomena [3–6], identification of bioactive non-nutrients [7–9]), traceability and confirmation of authenticity [10] of dairy products.
[1] M. Stuknytė, S. Cattaneo, F. Masotti, I. De Noni, Food Chemistry, 168, 27–33 (2015)
[2] S. Cattaneo, F. Masotti, L. Pellegrino, Journal of Agricultural and Food Chemistry, 57, 10689–10694 (2009)
[3] S. Cattaneo, M. Stuknytė, L. Pellegrino, I. De Noni, Food Chemistry, 155, 179–185 (2014)
[4] F. Masotti, I. De Noni, S. Cattaneo, M. Brasca, V. Rosi, M. Stuknyte, S. Morandi, L. Pellegrino, International Dairy Journal, 33, 90–96 (2013)
[5] F. Masotti, J. A. Hogenboom, V. Rosi, I. De Noni, L. Pellegrino, International Dairy Journal, 20, 352–359 (2010)
[6] S. Cattaneo, J. A. Hogenboom, F. Masotti, V. Rosi, L. Pellegrino, P. Resmini, Dairy Science and Technology, 88, 595–605 (2008)
[7] V. Taverniti, M. Stuknyte, M. Minuzzo, S. Arioli, I. De Noni, C. Scabiosi, Z. Martinez Cordova, I. Junttila, S. Hämäläinen, H. Turpeinen, D. Mora, M. Karp, M. Pesu, S. Guglielmetti, Applied and Environmental Microbiology, 79, 1221–1231 (2013)
[8] I. De Noni, S. Cattaneo, Food Chemistry, 119, 560–566 (2010)
[9] I. De Noni, Food Chemistry, 110, 897–903 (2008)
[10] R. Russo, V. Severino, A. Mendez, J. Lliberia, A. Parente, A. Chambery, Journal of Mass Spectrometry, 47, 1407–1414 (2012
Imprenditorialità, multi-culturalità e competitività territoriale: il ruolo dell’imprenditore immigrato
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Study on the variability of fucosidase activity in bovine milk by means of HPLC
No full textVariability of α-l-fucosidase (FUC) activity in bovine milk was evaluated with respect to season, keeping conditions and location of herd. A HPLC method was firstly set up in order to overcome some limitations of both colorimetric and spectrophotometric assays. The HPLC method was capable of determining FUC activity lower than 3 nmoles mL-1 h-1 and, for higher values, it gave comparable results with respect to the reflectance colorimetric assay. Samples (n=125) of raw bulk milk from 22 herds, consisting of 500-600 Holstein-Friesian cows each, were collected in a restricted area of Northern Italy from January to June 2004. The average enzyme activity in each month was in the range 47.5-51.0 nmoles mL-1 h-1. FUC activity in milk from different herds did not vary to a large extent during the 6-month period since average values from 44.8 to 53.4 nmoles mL-1 h-1 were recorded. Only milk samples from 2 herds presented significantly (P30 nmoles mL-1 h-1) can be expected when raw milk with FUC activity >50 nmoles mL-1 h-1 is submitted to mild thermization conditions (i.e. 57-58°C for 15 s). This problem was not overcome even when the evaluation of FUC activity was coupled with the determination of alkaline phosphatase
Release of beta-casomorphins 5 and 7 during simulated gastro-intestinal digestion of bovine beta-casein variants and milk-based infant formulas
No full textThe release of beta-casomorphin-5 (BCM5) and beta-casomorphin-7 (BCM7) was investigated during simulated
gastro-intestinal digestion (SGID) of bovine b-casein variants (n = 3), commercial milk-based infant formulas
(n = 6) and experimental infant formulas (n = 3). SGID included pepsin digestion at pH 2.0, 3.0
and 4.0 and further hydrolysis with Corolase PPTM. beta-Casein (b-CN) variants were extracted from raw
milks coming from cows of Holstein-Friesian and Jersey breeds. Genomic DNA was isolated from milk
and the b-CN genotype was determined by a PCR-based method. Phenotype at protein level was determined by capillary zone electrophoresis in order to ascertain the level of gene expression. Recognition
and quantification of BCMs involved HPLC coupled to tandem MS. Regardless of the pH, BCM7 generated from variants A1 and B of b-CN (5–176 mmol/mol casein) the highest amount being released during SGID
of form B. As expected, the peptide was not released from variant A2 at any steps of SGID. BCM5 was not
formed in hydrolysates irrespective of either the genetic variant or the pH value during SGID. Variants A1,
A2 and B of b-CN were present in all the commercial infant formulae (IFs) submitted to SGID. Accordingly,
16–297 nmol BCM7 were released from 800 ml IF, i.e. the daily recommended intake for infant. Industrial
indirect-UHT treatments (156 °C x 6–9 s) did not modify release of BCM7 and, during SGID, comparable
peptide amounts formed in raw formulation and final heat-treated IFs
Markers molecolari per la valutazione del danno termico e dell’invecchiamento del latte
No full textI trattamenti termici ai quali viene sottoposto il latte alimentare sono finalizzati alla distruzione di microrganismi e enzimi. Gli stessi trattamenti si traducono anche in una serie di modificazioni la cui entità dipende dai binomi tempo/temperatura applicati. Le modificazioni indotte dai trattamenti di pastorizzazione sono in generale trascurabili. Più importanti sono i cambiamenti causati dai processi di sterilizzazione, anche se l’adozione di corrette pratiche industriali e l’attuale impiantistica consentono di ottenere latte sterilizzato UHT di elevata qualità in termini di valore nutrizionale e sensoriale. La valutazione degli effetti del trattamento di sterilizzazione è in genere basata sullo studio di cambiamenti chimici irreversibili a carico dei costituenti del latte e ascrivibili all’isomerizzazione del lattosio e all’interazione di quest’ultimo con le proteine del latte durante la fase iniziale e avanzata della reazione di Maillard. Queste modifiche, quando analiticamente rilevabili, offrono la possibilità di individuare maker molecolari per valutare le proprietà qualitative e la genuinità del latte sterilizzato.
La durabilità rappresenta un indubbio valore commerciale del latte alimentare che ha determinato l’introduzione di tecnologie, quali la microfiltrazione, complementari al trattamento termico nella preparazione del latte pastorizzato. La durabilità di questo tipo di latte dipende da diversi fattori: tipo di trattamento termico e/o atermico, tipo e quantità di microrganismi, enzimi presenti, e condizioni di conservazione. In relazione a tali fattori, il latte pastorizzato può subire fenomeni degradativi dovuti all’azione di proteasi endogene e/o batteriche. La conseguenza è la formazione di peptidi utilizzabili quali marker molecolari per valutare l’invecchiamento del latte pastorizzato durante la conservazione refrigerata, ma anche utilizzabili per studiare lo stesso fenomeno durante la conservazione del latte crudo.
Nel complesso, i marker molecolari citati possono fornire al tecnologo un approccio innovativo per la definizione delle condizioni di conservazione e processo più idonee per l’ottenimento di latte alimentare con le desiderate caratteristiche qualitative. In questa relazione vengono descritti i principali meccanismi molecolari coinvolti nelle modifiche del sistema “latte” e i marker molecolari che gli stessi meccanismi originano durante i trattamenti di conservazione o termici applicati al latte
Reference material needs for quality assessment of milk and dairy products. 2004. Accreditation and quality assurance
No full textCommon market organization
of milk and dairy products includes
regulations intended to guarantee
prices and subsidies to some
products (e.g. butter and skimmedmilk
powder) provided they meet
specified compositional requirements.
Despite this, only a few reference
materials along with robust and
easy-to-apply analytical methods to
assess the genuineness of dairy products
are available. A short description
of the problems in establishing
authenticity of these products with
respect to the available reference
materials is presented. Processing innovations
and the availability of new
ingredients are changing the characteristics
of some traditional dairy
products. The development of the
food policy of the European Union
has taken these issues into account
by demanding traceability of both
finished food and ingredients.
Hence, the recognition of product
characteristics or processing technology
always implies adoption of new
analytical approaches along with
new reference materials. These requirements
demand for more comprehensive
knowledge of the food
manufacturing chain with special
regard to chemical modifications
which can be directly related to the
quality of the raw materials or the
processing conditions. Some analytical
approaches considering these
requirements as well as the most appropriate
characteristics of the related
reference material are discussed
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