Extruded Pasta

Dried or freeze dried samples can be extracted with water-immiscible solvents such as EtOAc or diethyl ether. For quantitative extraction, dried samples are preferably rehydrated at different times for example, 5 to 10 min for dried mangoes, 30 min for lyophihzed red peppers and pasta. Rehydration is followed by extraction with acetone or MeOH. Bixin and norbixin from a mix dry powder of annatto and com can quantitatively be extracted with MeOH followed by acetone. In order to improve pigment recovery, extruded foods require pre-digestion with enzymes to liberate the pigment from the matrix. ... 

To achieve a compound that meets these feeding requirements, compounders form their product into small pellets. To obtain these small pellets, they use specialized dies consisting of a metal plate with many small holes through which the molten compound is forced. This part of the process is very similar to how spaghetti is formed from pasta dough. To generate small pellets, the extruded strands are chopped into small pieces by rotating blades. 

Extruders are normally classified by their method of construction, i.e. twin screw or single screw and the operating conditions, i.e. cold extrusion or extrusion cooking. Cold extrusion is used to make liquorice and pasta among other products and so is outside the scope of this work. Extrusion cooking, which is defined as heating the product above 100 °C, has many uses. 

We now consider the extrusion-spheronization process, which is a widely used method of obtaining multiparticulate dosage forms. The drug substance is mixed with a diluent, a binder (and possibly with other excipients), and water, and kneaded to obtain a wet plastic mass. This is then extruded through small holes to give a mass of narrow pasta-like cylinders. These are then spheronized by rapid... 

Several applications can be found in literature regarding the use of NIR for the paediction of the main physical and rheological parameters of pasta and bread. De Temmerman et al. in 2007 proposed near-infrared (NIR) reflectance spectroscopy for in-line determination of moisture concentrations in semolina pasta immediately after the extrusion process. Several pasta samples with different moisture concentrations were extruded while the reflectance spectra between 308 and 1704 ran were measured. An adequate prediction model was developed based on the Partial Least Squares (PLS) method using leave-one-out cross-validation. Good results were obtained with R2 = 0,956 and very low level of RMSECV. This creates opportunities for measuring the moisture content with a low-cost sensor. 

Piston extruders are used in the foodstuffs industry, notably in the production of pasta, and are also employed for the shaping of aluminium profiles, wrought copper alloys and steel, for the extrusion and de-watering of sewage sludge, for the extrusion of hard metal, graphite, coal, plastics, etc. 

Andrieu, J., Jallut, C., Stamatopoulos, A., and Zafiropoulos, M., Identification of water apparent diffusivities for drying of com based extruded pasta, Proceedings of the Sixth International Drying Symposium (/DS 88), Versailles, France, 1988, pp. OP71-OP74. 

For foodstuffs extruders used for pasta and cereals food cooker-extruder used for soup bases, puffed products, dry cereals, textured proteins and pet foods. 

Heat and shear within the extruder barrel denature proteins thus many enzymes are inactivated. As a function of denaturation, protein solubility in water or dilute salt solutions is reduced, thereby changing protein functionality. SME may influence solubility more than does barrel temperature (Della Valle et aL, 1994). Wheat protein solubility decreases even at the relatively low temperatures (< 100°C) used for pasta extrusion (Um-madi et aL, 1995a). Large proteins may become dissociated into smaller subunits. Denaturation also exposes enzyme-susceptible sites, thus improving digestibility. 

Tunnel conveyor, belt or pasta, vegetables, gelatin, fruits, nuts, breakfast flakes, extruded... 

Ordinary butter (the toast type) is another example of a liquid/semisolid, depending on temperature. Butter is really a slurry of water in fat, differing from many materials of similar stiff room temperature textures in that its production is essentially a room temperature operation. Materials of this type can be sampled with a core-type sampler in the semisolid state or by methods previously described, in the liquid state. They can also be sampled by an extmsion system, whereby the sample is chopped off from an extruded stream. It is important that temperature be controlled so that the cut surface remains level and does not start to flow. Cheese is even more solid and can be sampled by simply taking a slice. Processed cheese is usually manufactured in the liquid state, and can be sampled and analyzed as-is, or fed into a sampling cell and allowed to solidify before analysis. Crumbly materials, such as biscuit (cookie) or cake doughs, dough mixes for pasta or noodle production or compressed (fresh) yeast, can be sampled manually or by an extrusion system. This includes thick slurries, which will eventually either solidify or be compressed into solid sheets or blocks. 

Pasta products are manufactured continuously by a vacuum extruder, which consists of a mixing trough and press segments. The vacuum is used to retard oxidative degradation of carotenoids. The semolina and added water (30%) and, when necessary, egg or egg powder are mixed in a mixing trough to form a crumb dough (diameter 1-3... 

Rehydration The quality of extruded cereal products, such as pasta, depends on extrusion temperature and the variety of wheat used in the extrusion process. The effect of varying the ratio of hard and soft wheat on the rehydration kinetics of extruded spaghetti has been investigated by MRI. By... 

Pasta products are divided, according to shape and size, into two broad categories short and long, and, according to processing method, into extruded, sheeted-formed, and precooked microwaveable. Today the market is dominated by dehydrated pasta, although fresh pasta is gaining in popularity. 

Precooked pastas are aimed toward cooking in a microwave or sold as convenience foods. In this case, the semolina is cooked and formed in a thermoplastic extruder and then dried, or the fresh pasta is cooked in water and then dehydrated (Figure 10.10). 

Small commercial presses or extruders are frequently used to test different types of semolinas and formulations for pasta product development. The fresh pasta could be... 

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