英文筆記-->Cereals

Dream

Cereals
Cereals:
Cereals are plants in the monocotyledon (单子叶植物)family Poaceae (Gramineae) that yield edible grains, eg. Wheat, barley, oats, rye, rice, maize, sorghum, millet.
Structure and Composition:
Dry, one-seeded fruits (caryopsis颖果) usually called kernels or grains.
Caryopsis consists of a pericary which surrounds the seed and is tightly bound to a seed coat.
The seed consists of an embryo (germ) and a large endosperm which is surrounded by a nucellar eqidermis and seed coat.
External to the seed coat are the glumes (chaff) which are remnants from the floral envelope.
The glumes may be tightly attached to the caryopsis and constitute the hull.
The hull is usually separated from the grain during threshing of wheat, rye, corn and sorghum.
Typical Percentage Composition of Cereal Gains
(Potter and Hotchkiss, 1995)
GrainMoistureCHOProteinFatIndig.Fibre
Corn11721042
Wheat11691323
Oats135810510
Sorghum11701242
Barley14631226
Rye11711222
Rice1165829

Composition varies according to cultivar, climate and soil types.
Moisture content is usually 10-14%, when levels are higher the grains require drying to prevent moulds and rots during storage.
Some moulds produce toxic metabolites – health risks (afflatoxins).
Proteins- lower nutritional value than most animal proteins due to lower levels of essential amino acid eg lysine.
Carbohydrate is usually digestible starches and sugars.
Milling removes much of the indigestible fibre (bran). Bran contains minerals and B vitamins which are lost – often added back- enrichment.
Milling also removes much of germ which contains oil and enzymes which can cause rancidity.
White flour - endosperm.
Whole grain flours contain bran layers and germ.

1.Wheat
Av wt kernels 35 mg, length 8mm
Kernels are rounded on one side (dorsal) and have a longitudinal crease which runs the length of the kernel and almost to the centre of the kernel.
Pericarp
Surrounding the entire seed, composed of several layers, comprises 5% of the grain.
Outer layer – beeswing
Inner layer – forms a plane of separation during milling
Seed coat and nucellar epidermis
Thick outer cuticle
A layer which may contain pigments
A thin inner cuticle
Aleurone
One cell thick, cells have thick walls. Surrounds endosperm and germ. Removed during milling along with pericarp, seed coat and nucellar epidermis and aleurone forming the bran as it is known by millers.
Germ (embryo)
Embryonic axis (roots and shoot initials) and scutellum (storage)
High in protein, sugar and oil
High in vitamin A and Vit E
Starchy endosperm
Comprised of cells with thin cell walls containing large amounts of the polysaccharides arabinoxylans (pentosans) and some (13, 14) – β-D-glucans but little cellulose.
Endosperm cells and their contents make up white flour.
Cells are packed with starch granules in a protein matrix.
Protein is mainly gluten, the storage protein of wheat.
Wheat classification in milling and baking terminology
Two types of wheat: hard and soft
Hard wheats contain high levels of protein and produce a strong flour, which produces an elastic dough and produces breads with a high volume.
Soft wheats contain less protein, produce a weaker flour and dough and are more suitable for cakes and biscuits.
Characterisation
1.Texture of the endosperm – this is related to the way the grains breaks during milling. Inherited characteristic.
Grains may have either:
Vitreous endosperm (steely, glassy) – hard and strong
Mealy endosperm (starchy, chalky) – soft and weak
Hard and soft wheat
Hardness and softness are related to the way the grains break during milling.
Hard grains fracture along cell boundaries, yield coarse gritty flour, regular shaped           particles, easily sifted and free flowing.
-Strong interaction between starch and protein
-Durum wheat – harder than most hard wheat
Soft wheats fracture randomly, through the cell contents.
-form fine flours, irregular shaped particles, difficult to sift

2.Proteins content – influences properties of flour and baking quality
Protein content caries, influenced by soil, fertiliser and climate conditions.
Higher protein in vitreous than in mealy wheats.
Summary
Strong wheat flours are those which have a high protein content and produce loaves with large volume good crumb texture and good keeping properties.
     Durum wheat – high protein, used for pasta.
Weak wheat flours have low protein, produce small loaves with coarse open crumb.
Flours from weak wheats are ideal for biscuits and cakes but not for bread (unless blended)
Milling of wheat (roller milling)
  Wheat is wasted to remove dirt and other material
  Soaked to achieve approx 17% moisture to facilitate milling
Milling separated the endosperm from the pericarp and germ. Grains are disintegrated into finer and finer particles by passing them through a succession of rollers followed by sieving.
Also involves impacting – particles thrown against a hard or abrasive surface.
Fractions (extractions)(line) are collected from points in the process.
Whites flour is that collected at the final stage.
Fractions are then combined to produce flours which suit customer needs.
Wheat flour products
Bread, buns, cakes, biscuits, crackers.
Cereals, sauces, soups.
Pasta, noodles.

insecteater

怎么看都象以前学的"食品专业英语",而不像是什么"笔记."
any way, thanks

Dream

是啊，我们老师就是这么教的阿~是老师的课堂笔记阿~

平安久久

thanks ,go on please!

zhf123

maybe this is very good,but I  didn';t  understand it .

jackli01

OH,MY GOD

Dream

what';s up man??

糊涂虫

梦梦好几天没来了,是不是学习很忙呀

Dream

下面引用由糊涂虫在 2005/09/10 10:06am 发表的内容：
梦梦好几天没来了,是不是学习很忙呀

啊呀！！！糊塗蟲姐姐我來了，我來了~我來了！！！！
是啊是啊，我前幾天一直在準備食品的考試，今天下午才攷完的，所以到現在才過來
~真是不好意思啊
不知道大家有沒有想夢夢啊？？^^

糊涂虫

想想想,怎么会不想呢
考得怎么样呀,咱梦梦一定是好样的,肯定没问题是吧

添乱

刚开始看，很好的英语气氛，正要用蹩嘴的英语说上两句
忽然 糊涂虫和dream的对话出现了 让我一下子又回到了中文思维了
破糊涂虫，是你！！让我失去了一个英文感慨的机会！！
找别的地方再教训教训你！这地方太严肃了，有损帖容！！

drizzle

I don';t understand the note either。
Where it can be used?