Material biscuit

A commercially interesting low calorie fat has been produced from sucrose. Proctor Gamble has patented a mixture of penta- to octafatty acid ester derivatives of sucrose under the brand name Olestra. It was approved by the FDA in January 1996 for use as up to 100% replacement for the oil used in preparing savory snacks and biscuits. Olestra, a viscous, bland-tasting Hquid insoluble in water, has an appearance and color similar to refined edible vegetable oils. It is basically inert from a toxicity point of view as it is not metabolized or absorbed. It absorbs cholesterol (low density Hpoprotein) and removes certain fat-soluble vitamins (A, D, E, and K). Hence, Olestra has to be supplemented with these vitamins. No standard LD q tests have been performed on Olestra however, several chronic and subchronic studies were performed at levels of 15% in the diet, and no evidence of toxicity was found. No threshold limit value (TLV), expressed as a maximum exposure per m of air, has been estabhshed, but it is estimated to be similar to that of an inert hpid material at 5 mg/m. ... 

Apart from butter or butter oil most fats that are used in biscuits are defined in terms of their physical and chemical properties. Fat suppliers are skilled at producing products with controlled physical and chemical properties from a range of raw materials. The baker can either buy fat on a physical and chemical specification, e.g. solid fat index, slip melting point, and not to contain lauric fat, or on an origin basis, e.g. to be coconut oil. The advantage of the botanical specification is that the item is a commodity and can be obtained from numerous sources. The disadvantage of this approach is that the product is tailored for a particular use. 

The major component of whey is lactose, and while there various uses for the protein in making protein concentrates these leave a surplus of lactose. Impure grades of lactose have been available to the food industry for some time. They are relatively successful in biscuits as a raw material for the Maillard reaction to produce pleasant colours and flavours. 

Like ferric nitrate, antimony sulfate is decomposed by water, various basic salts being formed, the simplest of which has the formula (SbOLSCL. The normal salt is stable only in rather concentrated sulfuric acid. Since this latter solvent has almost no vapor pressure at ordinary temperatures, the moist salt cannot be dried by evaporation of the solvent. It cannot be dried on absorbent paper, since the oily liquid rapidly carbonizes it. In such a case, it is best to take advantage of the drying qualities of unglazed earthenware (porous plate), such as the biscuit which forms the body of dishes. Owing to the fine pores which this material contains, liquids are sucked up by it by capillary attraction, and it is not acted upon by most reagents. 

Fill a small iron crucible about one-half to two-thirds full of magnesium powder. Bore a pinhole in the iron lid and then place the lid on the crucible. Lute the lid to the crucible with wet asbestos pulp and close the hole with the same material. (If a lid is not available, twist the crucible on a piece of asbestos board like a biscuit cutter until a deep groove has been cut in it and then lute it to the crucible as before.) Dry the crucible and its contents in an air oven or on the hot plate and when they are dry pierce a small hole in the asbestos plug with a pin. Place the crucible in a circular hole... 

Solids usually have larger ultrasonic velocities and acoustic impedance, than liquids, which have larger values than gasses. Air has a very low acoustic impedance compared to liquids or solids which means that it is difficult to transmit ultrasound from air into a condensed material. This can be a problem when ultrasound is used to test dry materials, e.g., biscuits or egg shells. A small gap of air between an ultrasonic transducer and the sample to be tested can prevent ultrasound from being transmitted into the material. For this reason coupling materials (often aqueous or oil based) can be placed between the transducer and sample to eliminate the effects of the air gap, or alternatively soft-tip ultrasonic transducers can be used. 

Evaluating odor and flavor taints is frequently done with water, fatty food simulants (oil, chocolate, unsalted butter), hydrophilic powders (sugar, cornflour), or combined hydrophilic-hydrophobic matrices (milk or cream, biscuits) (Kilcast, 2003). The Robinson test often is used to evaluate materials for tainting potential. This test places the test material in a sealed container separated from the food simulant or test food at a relative humidity between 53% and 75%. After about 48 h, the test food is evaluated for taint compared to a control, using a discrimination method (Lord, 2003). Chocolate is frequently used as the food simulant for this test. Intensity of the taint may be evaluated using a... 

Preform A compressed tablet or biscuit of plastic composition used for efficiency in handling and accuracy in weighing materials, (v.) To make plastic molding powder into pellets or tablets. 

The preparation of the catalyst can be exemplified by a description of the operations involved in the case of nickel. Unglazed biscuit-ware, broken to the size of peas, and freed from iron by boiling for several days with dilute hydrochloric acid, is rendered more porous by heating to redness for half an hour. After immersion in a concentrated solution of nickel nitrate, and evaporation of the liquid, the material is dried at 100° C., and subsequently heated until evolution of oxides of nitrogen... 

For studies carried out investigating the nature of foodstuffs, MPPO was replaced by wheat biscuit breakfast cereal (representing a dry foodstuff with low fat content), savoury biscuits (dry foodstuff with high fat content), butter (fatty foodstuff) or orange juice (acidic foodstuff). PP film was used as the primary packaging material for the studies with foods. Conclusions from the studies were as follows ... 

Validated methods are just as important as the availability of reference materials for allergens [21], As peanut allergy is highly prevalent and peanut products may enter into the production of various food matrices, e.g. chocolate, ice cream, biscuits and breakfast cereals, it is essential to have a peanut reference material both for research and routine analysis. Peanuts available in the food sector are derived from various sources, such as peanut vari-eties/types from different geographical origins, and are treated by various technological processes, such as dry and oil roasting at various temperatures for various times. 

Hemicellulases endo- and exoxylanases, pentosanases, mannases, arabinases, galactanases Bread and biscuit making, brewing, processing of plant derived materials, starch and gluten processing, coffee manufacturing, animal feed... 

In utilizing these results to predict ionization and valence in food materials tomato juice (Eh=2Uo), biscuit dough (Eh=3Uo), cranberry juice (Eh=U00) one would expect that the percentage iron ionized would be the same in each food since redox potential was found to have no effect in the model system on ionization. However research previously cited (U3.) showed that this was not the case as was seen in Figure 7. Obviously, this means that reduction potential of the food material is not a major factor in determining ionization of added iron. 

Lord Kelvin realized that, instead of completely drying out, moisture is retained within porous materials such as plants and vegetables or biscuits at temperatures far above the dew point of the surrounding atmosphere, because of capillary forces. This process was later termed capillary condensation, which is the condensation of any vapor into capillaries or fine pores of solids, even at pressures below the equilibrium vapor pressure, Pv. Capillary condensation is said to occur when, in porous solids, multilayer adsorption from a vapor proceeds to the point at which pore spaces are filled with liquid separated from the gas phase by menisci. If a vapor or liquid wets a solid completely, that is the contact angle, 0= 0°, then this vapor will immediately condense in the tip of a conical pore, as seen in Figure 4.8 a. The formation of the liquid in the tip of the cone by condensation continues until the cone radius, r, reaches a critical value, rc, where the radius of curvature of the vapor bubble reaches the value given by the Kelvin equation (r = rc). Then, for a spherical vapor bubble, we can write... 

The solid surface is inhomogeneous. This is virtually always the case if the material contains several components that are not fully mixed, which is very common in foods consider, e.g., chocolate, biscuits,... 

Texture. A hard biscuit has a crisp or brittle texture. This implies that it deforms in a fully elastic manner upon application of a force, until it breaks (snaps) at a relatively small deformation. Breakage goes along with a snapping sound. It appears from empirical observations that a crisp material has an apparent viscosity of at least 1013 or 1014 Pa s. The water content or temperature above which crispness is lost closely corresponds to Tg. Sensory evaluation shows that an increase in water content by 2 or 3 percentage units, or in temperature by 10 or 20 K, can be sufficient to change a crisp food into a soft (rubbery) material. 

Since it is sometimes difficult to identify whether a material is a single ply or a multiple ply, most students should examine a range of thinner materials to try to establish any constructional differences. However, many apparent single ply materials, e.g. biscuit, confectionery and chocolate (bar) wraps are actually multi-ply materials these frequently use a type of OPP (oriented polypropylene—especially the pearlised variety) where a special (coextruded) outer and inner heat seal ply has been added. MAP and CAP food materials are likely to have an anti-mist coating. 

The products that can be handled by today s automatic sorting machines include seeds, coffee, rice, breakfast cereals, nuts and pulses fresh, frozen and dehydrated vegetables cherries (with and without stalks) olives tomatoes prawns biscuits and confectionery. Foreign material such as stones, sticks and organic matter can be removed, as well as objects with defects such as discoloration and damaged skin. Figures 6.2 and 6.3 show two typical sorting machines. 

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