Bread testing

The aroma of fmit, the taste of candy, and the texture of bread are examples of flavor perception. In each case, physical and chemical stmctures ia these foods stimulate receptors ia the nose and mouth. Impulses from these receptors are then processed iato perceptions of flavor by the brain. Attention, emotion, memory, cognition, and other brain functions combine with these perceptions to cause behavior, eg, a sense of pleasure, a memory, an idea, a fantasy, a purchase. These are psychological processes and as such have all the complexities of the human mind. Flavor characterization attempts to define what causes flavor and to determine if human response to flavor can be predicted. The ways ia which simple flavor active substances, flavorants, produce perceptions are described both ia terms of the physiology, ie, transduction, and psychophysics, ie, dose-response relationships, of flavor (1,2). Progress has been made ia understanding how perceptions of simple flavorants are processed iato hedonic behavior, ie, degree of liking, or concept formation, eg, crispy or umami (savory) (3,4). However, it is unclear how complex mixtures of flavorants are perceived or what behavior they cause. Flavor characterization involves the chemical measurement of iadividual flavorants and the use of sensory tests to determine their impact on behavior. 

Levels of the enzyme a-amylase in wheat grains also affect breadmaking quality. Flour for bread-making requires low levels of a-amylase and this is favoured by a dry ripe dormant grain. The Falling Number (Hagberg) Test is used to determine a-amylase levels. A... 

In theory, analytical testing ought to be able to answer all pertinent questions but, unfortunately, it can not. While measuring the protein content will discriminate between a low protein flour and a high protein flour, the protein content will not necessarily guarantee that a given flour will make a satisfactory loaf of bread. The problem is that it is much easier to measure the quantity of protein present rather than its quality. 

Test baking is one answer to this problem some flour samples that had a good measured composition produce a poor loaf of bread. There are also samples that do not have very promising measured properties... 

Some empirical testing regimes, particularly those used to test the suitability of flour for products other than bread, have come about because of a need for a rapid test to show that a flour would work in a specific plant. Some cases require a test that can distinguish between flours that have a similar analysis but where only some of the flours would be satisfactory. 

This test, which has been adapted as BS 4317 AACC 151 and ICC 56-70, is used to determine the bread-making quality of wheat or flour. It is really an acceptance test for a flour mill rather than one for the bakery laboratory. 

Dough development is a fundamental process in bread making, without it there is just a paste of flour, water and the other ingredients. If the bread is to expand and form a proper cell structure then this change must take place. While it is quite easy to test for dough development by prodding some dough with a thumb it is more complicated at a chemical level. 

Triticale flour has been extensively tested in Poland, a country where rye bread is traditional. The best results were obtained by using 90% triticale flour with 10% rye flour. The rye flour was made into a flour brew for 24 hours at 28-29°C. Half the triticale flour was made into a sour dough for 3 hours at 32°C followed by mixing with the rest of the ingredients plus 1.5% of salt on the flour weight. The bread was then scaled and proved for 30 min at 32°C followed by baking at 235-245°C. 

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. 

In this variation the sample has no fat added while the control is the standard recipe. Either the bulk fermentation or the sponge batter method could be used for this test but the same method should be used as was used in variation 2. Similarly, the shelf life of the bread should be examined. 

An obvious use of bake testing is to compare the performance of two different batches of flour. In this exercise it is suggested that the control batch is a bread flour while the test should be a non-bread-making soft flour such as an English plain flour. 

When I was tested for my allergies I thought Oh, I hope I don t have to give up ice cream I hope I don t have to give up bread I hope I don t have to give up this and that. Well, it turned out to be all of that. I had to give it all up. No sugar. No chocolate. No milk. Can t have ice cream. Can t have corn. Can t have wheat. 

Utilization of iron was not affected at levels of 9 to 26g bran/day from corn or wheat (19, 2J0 2 ) or bY 16 g of bran/day (25). Negative balances were observed by Morris and Ellis (21) during the first balance period with daily intakes of 36g bran but not during the second 5-day balance period. However, Simpson et al. (24) found a marked inhibition of non-heme iron absorption from a single test meal which included 6 g of wheat bran. With a diet which provided 35g/day of NDF (neutral detergent fiber from bran bread), iron balances were decreased (26) compared to the 9 or 22g/day intake levels. 

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).

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