Therefore, it is better to eat less puffed food!
Types and principles of puffed food
Puffed food, also known as extruded food, explosive food and light food abroad, is a new type of food developed internationally in recent years. It uses grains, beans, potatoes and vegetables as raw materials, and is processed by expansion equipment to produce a variety of foods with beautiful appearance, rich nutrition, crispy and delicious. Therefore, a large category of food has been formed in a unique way. Due to the simple structure, convenient operation, less equipment investment and quick income, the equipment for producing this puffed food has developed rapidly, showing strong vitality.
Due to different uses and equipment, puffed food has the following three types: one is to use corn and potatoes as raw materials to produce snacks with an extruder; Secondly, using plant protein as raw material, tissue protein food (plant meat) is produced by extrusion extruder; The third is to use cereals, beans or potatoes as raw materials and make them into staple food after puffing. In addition to the trial production of indirect heating puffing machine, a variety of puffed foods were made from refined grain puffed powder.
Category 1. Staple food: sesame seed cake, bread, steamed bread, pancakes, etc.
2. Camellia oleifera: puffed noodle tea.
3. Military food: compressed biscuits.
4. Pastry: peach crisp, oven fruit, eight pieces, crisp cakes, moon cakes, printed cakes, egg rolls, etc.
5. Snacks: popcorn, cakes, etc.
6. Cold food: filling of sorbet and popsicle.
Some of the above foods, such as puffed flour tea, printed cakes and compressed biscuits, are all made of puffed coarse grains. Some varieties are only mixed with a certain proportion of puffed coarse grains.
Although expansion technology belongs to physical processing technology, it has its own characteristics. Expansion can not only change the shape and state of raw materials, but also change the molecular structure and properties of raw materials and form some new substances.
Principle When the grain is put into the bulking machine, with the progress of heating and pressurizing, the moisture in the grain becomes overheated and the grain itself becomes soft. Open the lid of the expander at a certain high pressure, which will soon become normal pressure. At this time, the overheated water in the grain suddenly vaporizes and explodes violently, and the water molecules can expand by about 2 000 times. The huge expansion pressure not only destroys the external morphology of the grain, but also breaks the internal molecular structure of the grain, cutting the insoluble long-chain starch into water-soluble short-chain starch, dextrin and sugar, so the insoluble substances in the puffed food are reduced and the water-soluble substances are increased. See the table below for details:
Table of Changes of Water Extracts in Food before and after Puffing (%)
raw material
corn
husked kaoliang
Before expansion
After expansion
Before expansion
After expansion
water extract
6.35
36.82
2.3
27.32
starch
62.36
57.54
68.86
64.04
dextrin
0.76
3.24
0.24
1.92
reducing sugar
0.76
1. 18
0.63
0.93
After puffing, except for the increase of water-soluble substances, a part of starch became dextrin and sugar. The expansion process changes the material state and properties of raw materials and produces new substances, that is to say, the chemical properties of products are changed by physical means of expansion, which puts forward a new topic for the theoretical research of food processing.
The process of decomposing starch in food into dextrin and sugar generally occurs in human digestive organs, that is, when people eat in their mouths, with the help of amylase in saliva, starch can be decomposed into dextrin and maltose, and finally glucose can be absorbed by the human body. Puffing technology plays the role of amylase, that is, starch is cracked before food enters the mouth. In this sense, the expansion device is equivalent to prolonging the human digestive organs. This increases the human body's digestion process of food and improves the digestion and absorption rate of puffed food. Therefore, it can be considered that puffing technology is a very scientific and ideal food processing technology.
Another feature of expansion technology is that it can completely α -starch Previously, the thermal processing technology that ripens food, such as baking and cooking, can also transform the original starch of food, namely β starch, into α starch, which is called α starch. However, after these products are left for a period of time, the expanded α starch shrinks back to β starch, which is called "retrogradation" or "aging". This is a common phenomenon in all starchy foods. After these foods are "aged", the body becomes hard, the taste becomes worse, and the digestibility decreases. This is due to the incomplete α -conversion of starch.
Expansion technology can completely α-starch, and the changed α-starch can not be restored to β-starch after being placed, so the food remains soft, has good flavor and high digestibility, which is another characteristic of expansion technology over other physical processing methods, and opens up a new processing field for intensive cultivation of coarse grains.
Advantages: 1 The taste and palatability are improved: after the coarse grains are expanded, the coarse and hard tissue structure is destroyed, and the samples of coarse grains can no longer be seen, and the taste of coarse grains can not be eaten, so the taste is soft, the palatability is improved, and the taste is delicious.
2. Convenient to eat: coarse grains have become cooked food after puffing, which can be directly taken with boiled water, or made into compressed food, and made into various foods after a little processing. It is convenient for eating and saves time. As long as the food department or factories, mines, enterprises, institutions and schools supply puffed powder, it can be processed and modulated in family or collective canteens and become a veritable convenience food.
3. The preservation rate and digestibility of nutrients are high; See table 1 ~ 3 for the preservation rate of nutrients during puffing. From the data in the table, the preservation rate and digestibility of nutrients in puffed food are relatively high, indicating that the puffing process has no effect on the nutrition of food, and its digestibility is higher than that of unexpanded food.
4. Easy storage: puffed grain is equivalent to one-time high-temperature sterilization, and the moisture content of puffed powder is reduced to below 10%. Such low moisture limits the growth of insects and molds, enhances their stability in storage, and is suitable for long-term storage, making war-fighting military grain and improving its edible quality.
5. Cheap price: With the indirect heating bulking machine, the processing cost per kilogram of corn is about 6 cents, which means that the price per kilogram of puffed corn flour is 26 cents. The monthly expenditure of local workers in China only increases coarse grains 10 kg per person per month, which is affordable for people. If the continuous automatic expander is developed in the future, its processing cost can be further reduced.
Table 1 table of nutritional components before and after puffing
nutritional ingredient
corn
husked kaoliang
Before expansion
After expansion
Before expansion
After expansion
Moisture%
16.80
9.6
14
9.2
Protein%
10.20
10. 17
9.45
9.49
vitamin B2
0.68
1.08
0.94
1. 17
(mg/g)
Table 2 Table of Vitamin Contents in Expanded Foods
kind
Puffed coarse rice
unpolished rice
Vitamin B 1 (mg/g)
0.53
0.30
Vitamin B2 (mg/g)
0. 10
0. 10
Vitamin B6 (ng/g)
100.00
83.40
E (mg/g)
7.72
7.79
Table 3 Test Table for Digestibility of Expanded Food
kind
Protein digestibility%
Carbohydrate digestibility%
Puffed coarse rice
83.80
99.45
unpolished rice
75.93
99. 10
milled rice
82.57
99.78