Bread slicing

As time goes by, the number of sandwiches increases, so A(sandwiches) is positive the rate of the process is given by A(sandwiches)/A(time). Alternatively, we would count the decreasing number of pickles at various times. Because A(pickles) is negative, we must multiply by (—1) to make the rate positive rate = -A(pickles)/A(time). If we measure the rate by counting slices of bread, we must also take into account that bread slices are consumed twice as fast as sandwiches are produced, so rate = -j(A(bread)/A(time)). Four different ways of describing the rate all have the same numerical value. 

A mould inhibitor in the form of sodium propionate was incorporated into films of cellulose acetate, the films were sandwiched between slices of bread and the sliced bread packed in LDPE bags and stored for 15 days at about 25C. The effect of the mould inhibitor on mould growth on the surface of the bread slices was investigated by means of microbiological analysis and water activity, moisture content and pH analyses. The presence of sodium propionate in the cellulose acetate films was found to have an inhibitoiy effect on microbial growth on the bread. 12 refs. 

The texture of bread was evaluated based on an instrumental Texture Profile Analysis (TPA). Bread slices (height 30 mm) were compressed with a universal testing machine (Zwick 1445, Ulm, G) to 15 mm with two repeating cycles. The crumb firmness and the elastic recovery were evaluated as described in ref. 8. The modulus of deformability of starch and flour gels was evaluated as described in ref. 7. 

Figure 4 shows the levels of carvacrol, in terms of peak area counts, reached in the headspace of the containers with bread slices after 0, 2, 5, 10 and 15 days of storage at room temperature. As it can be seen, an increase in the amount of carvacrol released from the PP films was observed with time for the bread samples. A high release of carvacrol was observed at 2 days, being released more slowly after 5, 10 and 15 days of storage. This mechanism of controlled release could lead to shelf-life improvement of the stored samples retarding the post-harvest deterioration. This behavior was also observed for strawberries. Regarding the thymol release, a similar trend was shown for both test food samples. 

FIGURE 4 Release of carvacrol in the headspace of bread slices after 0,2, 5,10 and 15... 

To illustrate how this procedure works, suppose you want to make grilled cheese sandwiches from 6 slices of cheese and 18 pieces of bread. The available cheese is enough for six grilled cheese sandwiches the bread is enough for 9. Clearly, the cheese is the limiting reactant there is an excess of bread. The theoretical yield is 6 sandwiches. Six grilled cheese sandwiches use up 12 slices of bread. Since there are 18 pieces available, 6 pieces of bread are left over. 

The smell of a home-baked loaf, the taste of a flaky crescent, the texture of a slice of whole-grain bread— all these experiences can come from very basic ingredients. The simplest breads are made from flour, water, yeast, and salt. This is fine for breads that are eaten the... 

How many sandwiches, each containing 1 slice of cheese and 2 slices of bread, can you make with 30 slices of bread and 20 slices of cheese ... 

Ans. With 30 slices of bread, the most sandwiches you can make is 15. The bread is the limiting quantity. 

A loaf of bread has 35 slices. Ann eats 8 slices, Betty eats 6 slices, Carl eats 5, and Derrick eats 9 slices. What fraction of the loaf is left ... 

Method. The method below is given for a large plant bakery making loaves of sliced bread. 

The cuisine of the countries where flat breads are eaten consists of curries and purees, which can be eaten conveniently by scooping them up with pieces of flat bead. This is analogous to the mediaeval custom of serving the food on a trencher, a slice of bread that was eaten at the end of the meal. 

Having made the loaves they have to be tested. When the loaves have cooled they can be measured and assessed. As bread is a perishable product it is convenient to photograph or otherwise make a record of the loaves produced to allow comparisons with samples made on a previous occasion. Digital photography is particularly convenient for this application. An alternative way of recording the amount that a loaf has risen is to photocopy a slice of bread with a ruler to allow the dimensions to be compared with future slices. 

Of course, the first slice of bread needs longer to become golden brown and crispy than the ones that follow, because the toaster will have heated up properly by then. This also goes for the Senseo Crema, the latest sensation in coffee brewing. 

Sampling and Analysis. A frozen slice of bread was cut in pieces and stacked in an enlarged sample flask of an aroma isolation apparatus according to MacLeod and Ames (74). Volatile compounds were trapped on Tenax TA and afterwards thermally desorbed and cold trap injected in a Carlo Erba GC 6000 vega equipped with a Supelcowax 10 capillary column (60 m x 0.25 mm i.d.) and a flame ionisation detector. Similar GC conditions were used for GC-MS identification of volatile compounds by dr. M.A. Posthumus (Dept. Organic Chemistry, VG MM7070F mass spectrometer at 70 eV El, 75). 

Color evaluation was carried out with a panel of 10 assessors, who judged coded slices of white bread in a Kramer ranking test design (76). 

Figure 1. Influence of 16-23 weeks of storage of soya containing bread improver paste and powder on visual whiteness of slices of bread. Kramer ranking test design (1 = most white sample, etc.) (C) = control, bread improver without soya flour has been used (based on data mentioned in text of 22).

The type (e.g., liquid, solid, powder, gel, syrup, emulsion, granule) and range of food samples (raw ingredients to final products) for water activity measurement are immense. The amount of sample required for measurement is typically 5 to 10 ml. A homogeneous and representative sample should be prepared and placed into the sample cup. For the majority of samples, no preparation is necessary the sample is simply placed into the cup. Multicomponent (e.g., muffin with raisins or pizza) and coated samples (e.g., breaded foods or chocolate-covered bar) may have to be sliced, crushed, or ground in order to obtain a representative sample. If sample preparation is necessary, then a consistent technique must be used with each sample to ensure reproducible results. 

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