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Wheat flour milling is a grinding process which gives different fractions of
wheat flour which affect the quality of bakery products (Shekara et al. 2011).
During wheat milling a portion of the starch granules sustains mechanical damage, the level of which depends on wheat hardness and milling technique. Millers are of the opinion that granulation is very important in the production of quality flour. It has been suggested that flour particle size, damaged starch and protein quality and quantity have effects on the baked products (Guttieri et al. 2001).
Hard wheat is more difficult to reduce to flour-sized particles. Therefore, hard
wheat flour has a larger mean particle size than that of soft wheat flour.
Alsberg and Griffing (1925) first reported that the flour particle size changes flour characteristics like water absorption, conversion of starch by enzymes, damage starch content and baking quality.
Okkada et al. (1986) found that grinding the same flour for an increased number of times increases the level of starch damage. Hard wheat produced larger flour particle with higher damaged starch levels when compared with soft wheat (Farrand 1972).
Hard and soft wheat fracture differently during the milling process which cause differences in damaged starch levels and particle size (Simmonds 1974).
Soft wheat flours are used for cookies. Flours that produce larger diameter and lower height cookies are considered to have better quality. Another aspect of cookie quality is the cracking that occurs on the top surface of the cookie referred to as cookie top grain. Good top grain (many surface cracks) results from recrystallization of sucrose at the cookie surface during baking (Doescher and Hoseney 1985).
Damaged starch absorbs much more water than intact starch. In soft wheat products, especially in cookies, high levels of damaged starch are detrimental to quality.
Gaines et al. (1988) demonstrated that increasing damaged starch led to sugar snap cookie of dough stiffness and decrease in cookie diameter.
Reduction of flour particle size reduces cookie spread because starch is damaged during particle size reduction (Yamazaki 1959).
Substituting damaged starch for flour in a sugar snap cookie formulation or for native prime starch in an all starch cookie model system increased alkaline water retention capacity (AWRC) and decreased cookie diameter (Donelson and Gaines 1998).
The objective of the study was to investigate the effect of particle size and damaged starch content on physicochemical characteristics of the wheat flour and cookie quality.
لتحميل الملف كاملا
https://www.ncbi.nlm.nih.gov/pmc/articl ... le_627.pdf