Clean vegetable processing

1. Raw material recovery and inspection

Not all vegetables are suitable for clean vegetable processing, and the selection of raw materials is important for the processing of raw materials. Vegetables can easily cause mechanical damage during harvesting and transportation. If tools need to be harvested, the tools should be sharp, and should be handled gently during handling; choose no mechanical damage, no insects, no disease spots, uniform color. Same size, same maturity, and reject unqualified vegetables.

2. Pretreatment of raw materials

The pretreatment of raw materials is mostly cooling treatment. That is, according to the characteristics of the raw materials, the temperature of the post-harvest vegetables is lowered to a suitable low temperature range as soon as possible by natural or mechanical means, and the low temperature is maintained to facilitate subsequent processing. Vegetables are filled with water, which is larger than heat, high in respiratory activity, fast in decay, and a period of rapid deterioration after harvesting. Pre-cooling is the link of cold chain circulation, and it is also the key to the success of the entire cold chain technology connection. Nowadays, cold water cooling, forced air cooling, vacuum cooling and other methods are used. Retail power

3. Cleaning and cutting

The purpose of cleaning is to wash away dust, dirt, microorganisms, parasite eggs and residual pesticides on the surface of vegetables. It must be carefully cleaned before processing. It can effectively extend the shelf life by cleaning with chlorine or citric acid in the amount of 100-200mg/L. Experiments have shown that the use of sodium hypochlorite to clean cut leaf lettuce can inhibit browning and the number of pathogens, but the treated raw materials must be cleaned to reduce the chlorine concentration to drinking water standards; because the chlorine residue contains potential for inducing organism mutations and Carcinogens, some new fungicides like ozone, electrolyzed water, etc. have been put into use. The traditional cleaning method is immersion cleaning and ultrasonic bubble cleaning. The size of the cut should be conducive to preservation, but also to meet the dietary needs, the cutting tool should be sharp.

4. Rinse, color protection and dehydration treatment

The vegetable raw material after cutting should be washed again to reduce microbial contamination and prevent oxidation. Color protection is mainly to prevent browning of fresh cut vegetables, browning is the main quality problem of fresh cut vegetables. There are many factors affecting the browning of vegetables, mainly the activity of polyphenol oxidase, the concentration of phenolic compounds, pH, temperature and the content of available oxygen in tissues. Therefore, it is possible to prevent browning by selecting a variety having a low phenolic substance, inactivating the activity of the enzyme, lowering the pH and temperature, and repelling the effective oxygen in the tissue. Traditional inhibition of browning using sodium sulfite is currently not allowed in the world. Commonly used sulfites are ascorbic acid, erythorbic acid, citric acid, L-cysteine, calcium chloride, EDTA, and the like. The washed vegetables should be dehydrated, usually dewatered using a centrifuge, and the centrifuge speed and dewatering time should be appropriate. Retail power

5. Packaging

Packaging is the post-operational part of the production of clean vegetables. At present, the packaging films commonly used in the packaging of fresh-cut products are polyethylene (PE), polypropylene (PP), low-density polyethylene (LDPE) and polyvinyl chloride (PVC), and composite packaging film ethylene-vinyl acetate copolymer (EVA). ) to meet different air permeability requirements. The packaging methods for fresh-cut vegetables are mainly self-regulating gas packaging (MAP), decompression packaging (MVP) and chitosan coating packaging.

 

Fresh vegetable preservation technology

1. Clean vegetable preservative application technology

Preservatives are chemically synthesized and natural preservatives. Most chemical antiseptic preservatives have certain side effects, which will bring a certain degree of pollution to fresh-keeping products. Especially for clean dishes, the types, dosages and timing of chemical antiseptic preservatives are strictly limited. Retail power

2. Low temperature refrigeration preservation technology

Low temperature can not only inhibit the respiratory intensity of clean vegetable tissues, reduce the speed of various physiological and biochemical reactions, delay aging and inhibit browning, but also inhibit the growth of microorganisms. Therefore, the selection, washing, packaging, storage, transportation and sales of clean vegetables must be carried out under a low temperature condition in order to obtain better preservation effect. Experts believe that after the clean vegetables are packaged, they should be stored in a cold storage. The temperature of the cold storage must be ≤ 5 °C in order to obtain sufficient shelf life and ensure the safety of the products, and use the cold chain (temperature ≤ 5 ° C) for transportation and sales.

3. Modified atmosphere preservation technology

The clean vegetables are easy to brown in the air, easy to be contaminated by microorganisms and have strong metabolism. The fresh vegetables are packaged in a modified atmosphere, so that they can be in a low-oxygen and high-carbon atmosphere, which can reduce their respiratory intensity, inhibit ethylene production, and delay the fresh cut. The food is aging and the shelf life is extended. At the same time, it can also inhibit the growth of aerobic microorganisms and prevent the corruption of fresh cut vegetables. The study found that: 5% to 10% CO2, 2% ~ 5% O2 gas atmosphere environment, can significantly reduce the vegetable respiration rate, inhibit enzyme activity, and extend the shelf life of fresh cut vegetables. The modified atmosphere of the clean dishes is mainly the self-regulating gas packaging (MAP). MAP is the passive generation of a regulated gas environment by the use of a suitable gas permeable packaging material, or the active production of a controlled atmosphere using a specific gas mixture and a combination of breathable packaging materials. Retail power

4. Other preservation technology

Non-chemical new preservation technology has broad application prospects in clean vegetable processing, mainly concentrated in: (1) physical preservation technology: using physical methods such as irradiation, air discharge, pulse electric field, oscillating magnetic field, high pressure, etc. Chemical changes occur, no odor is produced, and its nutrients, freshness and flavor can be preserved; (2) Biological control technology: Use some metabolites of beneficial microorganisms to inhibit harmful microorganisms, thereby prolonging the storage period of foods, such as those produced by lactic acid bacteria fermentation. Lactic acid.

At present, the more advanced preservation technologies studied at home and abroad mainly include critical low temperature and high humidity preservation, intercellular water structured gas conditioning, ozone gas conditioning, low dose radiation pretreatment preservation, high pressure preservation, genetic engineering preservation, cell swell pressure. Regulate preservation.

5. Cold chain technology

The cold chain is an important means to maintain the color, aroma and taste of food, and the cost is lower and the preservation time is longer. Temperature is the main factor affecting the quality deterioration of clean vegetables. At present, in the production of clean vegetables, foreign countries mainly use low-temperature refrigeration sales systems. The main links in the cold storage chain of clean vegetables include: pre-treatment of raw materials, pre-cooling, refrigeration, circulation and transportation, and distribution and distribution. The circulation of clean vegetable cold chain is a systematic project. From the perspective of the logistics direction of clean vegetables, it is divided into three parts: production area, sales area and production and sales connection area. Production areas include harvesting of fruits and vegetables, post-harvest commercialization (selection grading, refurbishment and packaging), pre-cooling and refrigerated production; sales areas include refrigerated sales, wholesale distribution (reclassification, refurbishment and packaging), retail and consumption Etc.; The link between production and sales mainly refers to short-distance and long-distance transportation of clean vegetables. The requirements for the cold chain required for clean vegetables are more complicated, and the variety of fruits and vegetables, the place of production, and the different growth period will affect the setting of the cold chain. The main technologies used in the cold chain include: pre-cooling, packaging, environmental control, transport delivery platforms, distribution and refrigeration. Retail power

 

Specific processing and preservation methods for various fruits and vegetables:

Cabbage (cabbage): After removing the yellow leaves, aged leaves, etc., weigh 250-300 grams, respectively, with A2 plastic bag set and bundle or tape the middle of weighed cabbage

Qingjiang Cuisine: Remove the aging, yellow leaves and cut off the aging part of the stem, respectively, weigh 250-300 grams, set the A2 plastic bag and bundle it, and put it in the freezer.

Water spinach (chives) : remove the roots to organize the aging part, after washing the soil with soil, weigh 250-300 grams, respectively, and set the A2 plastic bag and put it in the refrigerator.

Celery: Wash the roots and stems of the soil, remove the broken stems, weigh 250-300 grams, respectively, remove the leaves and weigh 150 grams in the refrigerator

Tube: Take out the yellow leaves and soil (do not use water), weigh 250-300 grams, respectively, and put them in A1 plastic bags and put them in the refrigerator.

Granite (Kaleopsis): remove the aged stems, weigh 250-300 grams and arrange them neatly, in A2 plastic bag set and sold in the bunch and freezer

Sugarcane: Remove aged leaves, weigh 250-300 grams and arrange them neatly, bundle them in plastic bags and put them in the freezer.

Brazilian (American parsley): remove the yellow leaves, weigh 50 grams and make the base neat, bundled with plastic bags, and then put them in the freezer for sale.

Lettuce: Remove the outer leaves, wrap them in plastic wrap and place them in a freezer.

Bowl seedlings: remove aged leaves, weigh 150-200 grams, with A2 plastic bag set beam mouth

Cabbage: cut off the prominent stem and outer leaves, directly packaged by insurance, the volume can be cut with a knife, and then placed in the freezer for sale.

Nine-storey tower: removes spots and damaged leaves, packs 100 grams into M2 tray, and wraps the cling film directly in the freezer.

Chinese cabbage (cabbage): cut off the protruding stem and green outer leaf, and wrap it directly with plastic wrap. The larger one is sold with a knife and cut in the freezer.

Coriander: Wash the roots, stems, and leaves of the sludge with water and remove the yellow leaves. Pack the amount of 100 grams into the M2 tray and wrap it in plastic wrap.

Rapeseed: Wash the soil with water, remove roots and aged leaves, etc., weigh 250-300 grams and arrange them neatly. Set them in A2 plastic bags and bundle them into flat shape.

Garlic: Remove roots and yellow leaves, wipe off unwashed sludge with a damp cloth, weigh 250-300 grams, and pack it in A3 plastic bag. The price is higher, weigh 150 grams.

Head: Dip the raw material into the water, wash the sludge with loofah cloth, and put it in the freezer after renovation.

Shallot: Cut the roots, but do not cut the scallion, leave the green stems and leaves about 5 cm long, and 4-5 in A4 plastic bags.

Carrot: Put the raw materials into the water, wash the sludge with loofah and renovate it, directly package it with plastic wrap, and put it in the freezer.

Onion: Remove the outer membrane by hand, grade it according to particle size, fill it with A5 plastic bag, 450-500 g/bag

Potato: Put the raw materials into the water, wash the sludge with loofah cloth and classify according to the particle size. Pack it in A5 plastic bag or pack it in M2 tray and put it in the freezer.

Amaranth: remove the yellow leaves, weigh 250-300 grams, and make the base neat, set the A3 plastic bag and bundle it. After the price, it will be sold in the freezer.

Bamboo shoots: Cut off the aging part, wipe the sludge with a damp cloth and pack it according to the size of A2 or M5. The larger one and the smaller one

Mung bean sprouts: 240-290 grams in trays, then put 10 grams of leeks as ingredients, wrapped in plastic wrap, after price, placed in open refrigerator

茭白笋: The raw material is shelled, to straighten the case, the depth is appropriate, the bamboo shoots have a green shell and remove the aging bamboo head (A3 plastic bag)

Lianhua: Put it in the water tank, soak it in water, remove the soil, drain it, put it in M7 tray and sell it in plastic wrap.

Asparagus: wipe off the sludge, grade it by size, weigh 250-300 grams, pack it in plastic bags or cling film and put it in the freezer.

Ginger: Wash and drain, put two tender gingers on the M2 tray and wrap them in plastic wrap and put them in the freezer.

Soybean sprouts: 250-300 grams of raw materials in trays, wrapped in plastic wrap, and then placed in a freezer.

Sweet potato: After draining the soil, drain it, sort it by size, pack it in mesh bag, or put 2-3 pieces in a tray, wrap it in plastic wrap, and put it in the freezer.

Taro: Remove the sharper and dry parts of the head, remove the brown hair and hair roots, and wrap the plastic wrap directly. The small steamed bun is loaded with about 6 M3 trays.

Gherkin: According to its length, the same length will be packed in the same bending direction with the M2 tray, the weight is about 300-500 grams, or wrapped in plastic wrap.

Cauliflower: cut off the peduncle, or leave 3-4 pieces of heart leaves, put them in a freezer and store them in a freezer.

Bitter gourd: directly packaged with plastic wrap, after weighing the price, put it in an open refrigerator

Broccoli: The stem is about 5 cm long, and the rest is cut, wrapped in plastic wrap and placed in a freezer.

Green beans: Remove the small bean clips, put them into A5 plastic bags at 250-300 grams and arrange them neatly, or load them into M2 trays.

Amaranth flower: Cut a little stem and aging part, weigh 150 grams, put it in A3 plastic bag and bundle it, or bundle the plastic bag after 1/3 of the removal.

Emperor Bean: Raw material shelling, shelling and leaving the kernel, 150kg in M2 tray, wrapped in plastic wrap, after price, placed in open refrigerator

Edamame: Remove the fruit stalks, leave the bean stalks, and pack them in M2 trays in 150 gram quantities, wrap them in plastic wrap or wrap them in green bags and sell them in a freezer.

Green pepper: wipe the sludge, the small ones are three, the larger ones are loaded into the A5 plastic bags and bundled, or loaded as trays.

Hairy Beans : Remove the residual beans and immature fruits from the raw materials, put 150 grams in M2 tray, and sell them in plastic wrap.

Chili: wipe off the sludge, sort by color, weigh them separately in units of 50 grams, and arrange them in M1 trays.

Corn: cut off the peduncle, make the 1/4 corn head appear, remove the pests, and pack the two with one layer of plastic wrap.

Eggplant: Remove pests and spoilage materials, classify according to size, put them into A3 plastic bags and bundle them in the refrigerator.

Corn kernels: the coarse chips are cut off, and the raw materials are blown with a fan. The M2 trays are filled with 150 grams, wrapped in plastic wrap and placed in a freezer.

Mushroom: brush to the mushroom handle, according to the size of three levels, 200 grams as a unit, weighed separately, packed in plastic box No. 6, wrapped in plastic wrap

Mushroom: Remove the flowering, blackening of the mushroom handle, according to the size of the umbrella, weighed separately with 150 grams, and then sold in the refrigerator with M3 tray and plastic wrap.

Papaya: Wipe the epidermis, stick the price on the fruit after the pound weight or first tape the middle part of the fruit, then stick the price on the tape.

Golden mushroom: brush the dirt on the handle of the mushroom, weigh it at 120-150 grams, pack it in M5 tray and wrap, and then sell the pineapple in the refrigerator with tape to tie the middle part. After weighing, stick the price on the tape. Head up, tail down  

Straw mushroom: cut off the dirt in the mushroom handle, weigh it separately with 150 grams, wrap it in M3 tray and plastic wrap, then sell it in the freezer.

Carambola: Two bottles of carambola are packed in M2 tray, packed in plastic wrap, and after being priced at a price, they are placed in a freezer.

Banana: processing heat, cut into 4-6 pieces for a small string, cut off each small string of stems, put on a tray, wrap with plastic wrap, or tape the middle part for sale

Lemon: Wipe the skin, grade it according to the particle size, store 4-6 pieces in M2 tray, wrap in plastic wrap, and put it on the freezer after weighing.

Grapefruit: Wipe the peel and grade it according to the particle size. Pack 4 or 6 in M5 tray, wrap it in plastic wrap. After weighing, put it on the refrigerator.

Melon: After the pound is heavy, put the price on the tape, the person with high maturity is placed on the refrigerator, and the low maturity is sold on the cabinet or platform.

Pomegranate: divided into two grades according to the size of the particles, the larger ones are packed in M2 trays, the smaller ones are packed in four M3 trays, wrapped in plastic wrap, and sold on refrigerated cabinets.

Dates: Wipe the fruit pieces, according to the size classification, in the M2 tray, neatly arranged, the pedicle is facing down, the tail is facing up, and the weight is sold on the refrigerator.

Thai guava: Directly priced on the bag of white bag, or use the plastic wrap to sell the tomato to wash the skin of the skin, drain, and wrap it in plastic wrap.

 

Lotus: According to the color and size classification, the same level with M11 installed 6, wrapped in plastic wrap and sold on the refrigerator

 

Lychee, longan: cut off the branches of fruit and bad fruit, take about 600 grams to renovate, make the upper part flush, bundle with net bag set and sell on the refrigerator

 

Liu Ding: Wipe the skin and indicate the unit price of kilograms. The customer will pack the bags themselves or four in the M2 tray. The bottom is sold upwards.

　

Pear: The grading standard is represented by A, which represents 5 sets of two... each, wrapped in plastic wrap and placed on a freezer for sale.

 

Watermelon: Wipe the epidermis and store it on a normal temperature platform. If it is a childless watermelon, cut it into two or four pieces. If it is a large watermelon, pack it in each piece with a plastic wrap.

 

Grapes: cut off bad particles, packed in M5 tray, wrapped in plastic wrap, after weight, placed on the refrigerator for sale

 

Cantaloupe: Wipe the epidermis, bundle the middle part with a plastic bag, or put it in a net bag and put it on the freezer.

 

Plum: Remove pests, etc., use M3 tray to hold about 400 grams and arrange them neatly, wrap them in plastic wrap and then in the freezer.

 

Kiwifruit: After grading the raw materials, set the H32-1 plastic box with two bundles, or place the whole box on the display cabinet. Customers can purchase it by themselves, hang POP, indicating the price.

 

Cherry: Remove the bad fruit after unpacking, so that the plastic box of the type can be sealed with 100-200 grams, and then put on the open refrigerator for sale.