Analysis of the water soluble compounds as a tool for discriminating traditional and industrial high moisture mozzarella made with citric acid

High moisture mozzarella from cow milk is a pasta filata cheese that can be manufactured by different protocols. Fermentation by autochthonous starter is used for the traditional product, whereas direct acidification with citric acid is widely used at industrial level. Both types are stored immersed in a liquid for preserving freshness, but this packaging method is known to favour the changes of the quality characteristics. The present study aimed to assess the evolution of the soluble compounds and to evaluate their use as chemical indices for discriminating the two types of mozzarella. The contents of lactose, organic acids, water soluble nitrogen and free aminoacids differently changed over time. The whole patterns of these soluble compounds allowed discrimination of the two products during the whole storage period. The simple analyses of lactic acid and lactose could be a rapid tool to protect traditional mozzarella from industrial imitations obtained with citric acid

Cheese ripening in nonconventional conditions: A multiparameter study applied to Protected Geographical Indication Canestrato di Moliterno cheese

A multiparameter study was performed to evaluate the effect of fondaco, a traditional ripening cellar without any artificial temperature and relative humidity control, on the chemical, microbiological, and sensory characteristics of Protected Geographical Indication Canestrato di Moliterno cheese. Ripening in such a nonconventional environment was associated with lower counts of lactococci, lactobacilli, and total viable bacteria, and higher presence of enterococci, in comparison with ripening in a controlled maturation room. Moreover, fondaco cheese underwent accelerated maturation, as demonstrated by faster casein degradation, greater accumulation of free AA, and higher formation of volatile organic compounds. Secondary proteolysis, as assessed by liquid chromatography-mass spectrometry of free AA and low molecular weight peptides, did not show any qualitative difference among cheeses, but fondaco samples evidenced an advanced level of peptidolysis. On the other hand, significant qualitative differences were observed in the free fatty acid profiles and in the sensory characteristics. Principal component analysis showed a clear separation of the fondaco and control cheeses, indicating that ripening in the natural room conferred unique sensory features to the product

Evolution of VOC and Sensory Characteristics of Stracciatella Cheese as Affected by Different Preservatives

Undesired volatile organic compounds (VOCs) can negatively affect the flavor of fresh food products; especially those characterized by a mild and delicate aroma. Finding connections between chemical and sensory analyses is a useful way to better understand the arising of off-flavors. A study was conducted on stracciatella; a traditional Italian cream cheese that is emerging on international markets. Samples were prepared by adding two different preservatives (alone or combined): sorbic acid and an olive leaf extract. Their influence on flavor preservation during refrigerated storage was investigated by chemical, microbiological and sensory analyses. A strong change of the VOC profile was ascertained after 8 days in the control cheese and in the sample added with leaf extract alone. The samples containing sorbic acid, alone or in combination with leaf extract, gave the best chemical and sensory results, demonstrating a significant shelf-life extension. In particular, these samples had lower concentrations of undesired metabolites, such as organic acids and volatiles responsible for off-flavor, and received better scores for odor and taste. Ex and Ex-So samples had significantly higher antioxidant activity than Ctr and So throughout the entire storage period, and the color parameter shows no differences among samples taken on the same day. The use of the olive leaf extract, at the concentration tested, seemed to be interesting only in the presence of sorbic acid due to possible synergic effect that mainly acted against Enterobacteriaceae

Effects of the Cooling Temperature at the Farm on Milk Maturation and Cheesemaking Process in the Manufacture of Parmigiano Reggiano PDO Cheese

Parmigiano Reggiano is a hard PDO cheese made from bovine raw milk, whose microbiological characteristics have important repercussions on cheese quality. According to the EU official production protocol, milk temperature at the farm must not drop below 18 °C. The present research aimed to study the effect of cooling milk at the farm at 9 °C on the characteristics of milk and on the cheesemaking process and losses during manufacture. Six cheesemaking trials were performed in two different dairies. In each of them, two cheesemakings were made in parallel: one with milk kept at 9 °C (TM9) and the other with milk kept at 20 °C (TM20). TM9 milk, in comparison with TM20, showed after the creaming process a significant reduction not only of total bacterial count but also of psychrotrophic and lipolytic bacteria. At the same time, TM9 milk showed a higher creaming capacity and, consequently, a lower fat content than TM20. TM9 vat milk had worst coagulation properties than TM20, which caused slightly higher loss of fat and curd fines into the whey. Nevertheless, these changes were too small to influence the efficiency of the cheesemaking process; conversely, maintaining milk at the farm at 9 °C led to a reduction of the number of spoilage bacteria

High performance waveguide uni-travelling carrier photodiode grown by solid source molecular beam epitaxy

The first waveguide coupled phosphide-based UTC photodiodes grown by Solid Source Molecular Beam Epitaxy (SSMBE) are reported in this paper. Metal Organic Vapour Phase Epitaxy (MOVPE) and Gas Source MBE (GSMBE) have long been the predominant growth techniques for the production of high quality InGaAsP materials. The use of SSMBE overcomes the major issue associated with the unintentional diffusion of zinc in MOVPE and gives the benefit of the superior control provided by MBE growth techniques without the costs and the risks of handling toxic gases of GSMBE. The UTC epitaxial structure contains a 300 nm n-InP collection layer and a 300 nm n++-InGaAsP waveguide layer. UTC-PDs integrated with Coplanar Waveguides (CPW) exhibit 3 dB bandwidth greater than 65 GHz and output RF power of 1.1 dBm at 100 GHz. We also demonstrate accurate prediction of the absolute level of power radiated by our antenna integrated UTCs, between 200 GHz and 260 GHz, using 3d full-wave modelling and taking the UTC-to-antenna impedance match into account. Further, we present the first optical 3d full-wave modelling of waveguide UTCs, which provides a detailed insight into the coupling between a lensed optical fibre and the UTC chip.Comment: 19 pages, 24 figure

Dry-aged beef steaks: effect of dietary supplementation with Pinus taeda hydrolyzed lignin on sensory profile, colorimetric and oxidative stability

Flavor is one of the main factors involved in consumer meat-purchasing decision and use of natural antioxidants in animal feeding had a great appeal for consumers. The aim of this trial is to evaluate the effect of Pinus taeda hydrolyzed lignin (PTHL) feed addition on oxidative stability, volatile compounds characteristics, and sensory attributes of 35 days dry-aged beef steaks. Forty steer six months old were randomly divided into a control group (CON; n = 20) and an experimental group (PTHL; n = 20). Both groups were fed ad libitum for 120 days with the same TMR and only the PTHL group received PTHL supplement. Samples of LT muscle were removed from carcasses and dry aged for 35 days at 2 °C, 82% of humidity, and 0.4 m/s of ventilation and then analyzed. Meat of CON group showed lower yellowness (p < 0.01) and higher TBARS (p < 0.01) values. Moreover, CON meat showed higher volatile aldehydes and lower sulfur compounds (p < 0.01), with higher unpleasant odor (p < 0.05) and meaty odor (p < 0.01) score revealed by sensory assessors. PTHL inclusion in beef diet delayed the oxidative mechanisms in 35 days dry-aged steaks, resulting in an improved colorimetric, volatolomic, and sensory profile

Dynamics of the Fermentation Process and Chemical Profiling of Pomegranate (Punica granatum L.) Wines Obtained by Different Cultivar×Yeast Combinations

Pomegranate (Punica granatum L.) is one of the historical tree crops in the Mediterranean region and is nowadays commercialized for its beneficial properties in the form of fruits, juice, jams and, in some East countries, as fermented juice (pomegranate wine). However, pomegranate wines are not established as a common beverage in Western countries. In this work, we produced pomegranate wines using two cultivars and two yeasts (Saccharomyces cerevisiae strain Clos and S. cerevisiae ex-bayanus strain EC1118) with contrasting characteristics. A comprehensive chemical profile of the wines was obtained. Notable differences were observed in the function of the cultivars and the yeasts. Different cultivar×yeast combinations provided wines with clearly different chemical profiles and specific features in the patterns of organic acids, phenolics, and volatile compounds. This highlights the opportunity to obtain tailored pomegranate wines with desired chemical profiles and, consequently, sensory properties, through management optimization of pomegranate winemaking. In this view, pomegranate wines have the potential to become an established beverage in Western countries

Coherent terahertz photonics

We present a review of recent developments in THz coherent systems based on photonic local oscillators. We show that such techniques can enable the creation of highly coherent, thus highly sensitive, systems for frequencies ranging from 100 GHz to 5 THz, within an energy efficient integrated platform. We suggest that such systems could enable the THz spectrum to realize its full applications potential. To demonstrate how photonics-enabled THz systems can be realized, we review the performance of key components, show recent demonstrations of integrated platforms, and give examples of applications

Prolungamento della shelf life della burrata: problematiche e prospettive

L’imponente crescita della domanda sui mercati esteri sta portando la burrata a essere uno dei formaggi più interessanti per la crescita del comparto lattiero-caseario nazionale. È quanto mai urgente la messa a punto di opportune strategie per prolungarne la shelf life e pervenire a una conservabilità di almeno 3-4 settimane in modo affidabile e riproducibile. Per il raggiungimento di questo obiettivo è necessario adottare un approccio “multifunzionale”, in grado di unire il rigoroso rispetto dell’igiene in processo con una tecnica di risanamento post confezionamento. A oggi, la tecnologia di risanamento più promettente sembra essere la HHP, la cui implementazione, oltre alla definizione puntale dei parametri operativi e delle confezioni compatibili con il trattamento, dovrà superare i limiti posti dai costi di investimento e dal trattamento in batch

An easy and natural way for producing lactose-free mozzarella without lactase

Lactose intolerance has given rise to an important new segment market of dairy products. In Europe, the limit for lactose-free labelling has been fixed at 0.1% per 100 g or mL by EFSA. The present communication describes the development of a new method for producing this cheese without using lactase