{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

flour - FLOUR Introduction The proteins in flour have...

Info icon This preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
FLOUR Introduction The proteins   in flour  have  unique  functional  properties.    These properties  and  the  nutritional importance of flour have made bread a staple in man's diet throughout history.  In  recent years, extensive research and development work has taken place to more clearly identify  the unique functional properties and the physical and chemical properties of flour proteins.  Before  discussing  the  various   food  products  made  with  flour,   we  need  to   understand   the  functional properties of flour proteins. Flour Proteins The   average   composition   of   flour   is   given   in   Table   1.     Based   on   solubility,   the  classification of flour proteins is given in Table 2.   The composition of cereal proteins with  regard to solubility is given in Table 3.  These classifications are usually considered sub-groups  of two major classifications, gluten (dough forming) proteins and non-gluten proteins.   For  wheat flour this grouping is shown in Figure 1.   The dough forming proteins, glutelins and  prolamines, are the components that impart the common structural and functional characteristics  to bread.   When hydrated, glutelin and prolamine form gluten.   The important properties of  gluten include the following: 1)   Ability to form a visco-elastic mass.   With a certain amount of mixing, hydrated  gluten develops into a firm, resilient, and adhesive substance which is insoluble in  water and exhibits both viscous and elastic properties. 2)   Ability to form films.   When the formed visco-elastic mass is further mixed or  kneaded,   it   develops   into   a   continuous   three-dimensional   web   of   films.     Solid  particles as well as gas bubbles may thus be enveloped throughout this continuous  gluten mass. 3)  Thermosetting ability.  When heated above 85 o C, the hydrated gluten mass coagulates  irreversibly without loss of its unique structural order, yielding a firm, non-sticky,  moist, clean cutting and resilient gel. 3-1
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Table 1.  Basic Composition of Flour. FLOUR Component Average   Composition Water 12% Protein 7-13% Fat 0.8-2% Carbohydrate 71-80% Ash 0.3-2%   Table 2.  Solubility Classification of Simple Proteins in Cereal Seeds. Albumins Soluble in water or dilute salt solutions Globulins Insoluble in water, soluble in salt solutions Prolamines  Insoluble in water and absolute alcohol, soluble in 80% alcohol (present in cereal seeds only) e.g. zein from corn, gliadin from wheat,   hordein from barley   Glutelins  Insolube in neutral solvents.  Soluble in dilute acids or bases (present in cereal seeds only) e.g. Glutenin from wheat, Oryzein from rice _____________________________________________________________ 3-2
Image of page 2
Table 3. COMPOSITION OF CEREAL PROTEINS (% ON A DRY MATTER BASIS).
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern