Introduction
Cereals are members of the grass family (Poaceae or Gramineae)
and produce dry one-seeded fruits (caryopsis) which are commonly
called a kernel or grain. All cereals consist of a fruit coat (pericarp)
surrounding the seed. The seed contains an embryo (germ) and an
endosperm surrounded by a nucellar epidermis and a seed coat
(testa). In addition, some cereals, such as rice, oats, and barley retain
their husk during threshing, which must be removed to produce
acceptable foods for humans. The bran consists of outer layers of the
grain of cereals, removed during the process of milling and used as a
source of dietary fiber. It generally comprises the fruit wall, seed
wall, aleurone layer, and small amounts of the starchy endosperm
and germ. Whole grain (WG) cereals and pseudocereals were
defined by the American Association of Cereal Chemist International
(AACCI) in 1999 as “the intact, ground, cracked, or flaked caryopsis
(kernel or seed), whose principal anatomical components e the
starchy endosperm, germ, and bran e are present in the same
relative proportions as they exist in the intact caryopsis” (Frolich &
Aman, 2010).
WG have always been recognized for their contribution of
traditional nutrients, B vitamins, minerals, and dietary fiber to the
diet. More recently, WG have been shown to be a good source of
bioactive components (e.g. phytoestrogens and plant sterols) and
antioxidants. In fact, the in vitro antioxidant activity of WG foods
has been shown to be at parity with that of vegetables and fruits
(Jones, Reicks, Adams, Fulcher, & Marquart, 2004). The effects of
consumption of one type of WG do not necessarily reflect the
magnitude of benefits for other WG due to the diversity of WG in
terms of macronutrients, micronutrients, and bioactive components
(Jones et al., 2002).
Food processing may produce either beneficial or deleterious
effects on nutrient bioavailability. Regarding minerals, processing
could increase the content of someminerals, destroy some inhibitors
or form beneficial complexes between minerals and matrix components.
The impact can be negative by deactivating enzymes that
degrade inhibitors or by generating insolublemetal compounds (e.g.
oxidation, precipitation) (Watzke, 1998).
IntroductionCereals are members of the grass family (Poaceae or Gramineae)and produce dry one-seeded fruits (caryopsis) which are commonlycalled a kernel or grain. All cereals consist of a fruit coat (pericarp)surrounding the seed. The seed contains an embryo (germ) and anendosperm surrounded by a nucellar epidermis and a seed coat(testa). In addition, some cereals, such as rice, oats, and barley retaintheir husk during threshing, which must be removed to produceacceptable foods for humans. The bran consists of outer layers of thegrain of cereals, removed during the process of milling and used as asource of dietary fiber. It generally comprises the fruit wall, seedwall, aleurone layer, and small amounts of the starchy endospermand germ. Whole grain (WG) cereals and pseudocereals weredefined by the American Association of Cereal Chemist International(AACCI) in 1999 as “the intact, ground, cracked, or flaked caryopsis(kernel or seed), whose principal anatomical components e thestarchy endosperm, germ, and bran e are present in the samerelative proportions as they exist in the intact caryopsis” (Frolich &Aman, 2010).WG have always been recognized for their contribution oftraditional nutrients, B vitamins, minerals, and dietary fiber to thediet. More recently, WG have been shown to be a good source ofbioactive components (e.g. phytoestrogens and plant sterols) andantioxidants. In fact, the in vitro antioxidant activity of WG foodshas been shown to be at parity with that of vegetables and fruits(Jones, Reicks, Adams, Fulcher, & Marquart, 2004). The effects ofconsumption of one type of WG do not necessarily reflect themagnitude of benefits for other WG due to the diversity of WG interms of macronutrients, micronutrients, and bioactive components(Jones et al., 2002).Food processing may produce either beneficial or deleteriouseffects on nutrient bioavailability. Regarding minerals, processingcould increase the content of someminerals, destroy some inhibitorsor form beneficial complexes between minerals and matrix components.The impact can be negative by deactivating enzymes thatdegrade inhibitors or by generating insolublemetal compounds (e.g.oxidation, precipitation) (Watzke, 1998).
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