How much is prawn per jin now? With key processing techniques

Prawn is a fairly popular aquatic product, also called Chinese prawn or oriental prawn. Whether braised, deep-fried or grilled, it tastes very tender and delicious. In recent years the prawn farming industry has expanded fairly quickly, and many farmers have taken up prawn farming. So how much is prawn per jin now? What are the key processing techniques?

1. How much is prawn per jin now?

Recently the price of prawn is roughly 30-170 yuan per jin, and the price is affected by factors such as place of origin, size grade, market conditions, purchase quantity and purchasing channel. For example, the price of prawn at the Shijiazhuang Qiaoxi Vegetable Center Wholesale Market is 31.5 yuan per jin; the price of prawn at the Weihai Aquatic Products Wholesale Market in Shandong Province is 170 yuan per jin.

2. Key points of prawn processing techniques

Raw material handling: raw materials entering the plant must all undergo quality and hygiene inspection. After passing inspection they should be put into processing promptly, and it is required that prawns be processed the same day they are caught; if they cannot be handled promptly, they should be re-iced to keep them fresh (temperature controlled below 8°C).

Initial washing: before processing, rinse with processing water to remove impurities.

Deheading: the raw materials should be deheaded on the specified work table or in clean, hygienic containers, discarding soft-shelled prawns and prawns that are not fresh or have severe mechanical damage; prawns showing obvious yellowing should be stored separately after deheading. During the operation, hold the prawn with the left hand, and with the right hand pull apart the joint between the head-thorax and the abdomen so that they separate and the viscera are pulled out.

Washing the prawns: wash with ice water; during washing use a small round basket rotated at a steady speed to prevent bruising the prawn bodies, and the amount of prawns held should not exceed 1/2 of the basket. Wash 3 times, and the final wash is best done with clean water.

Grading: place the washed prawns on the work table and sort them carefully according to size standards; coarse sorting, fine sorting and grade-based sorting may be used. During sorting, do not let raw materials pile up too much on the work table, and crushed ice should be added to keep them fresh.

Rinsing: rinse the prawns once with ice water at about 6°C.

Draining: after rinsing, place the prawns in a colander to drain for 5 minutes to remove the water remaining on the surface of the prawn bodies; when draining, do not put too many prawns in the container.

Weighing: before weighing and during the operation, the scale must be calibrated to ensure accurate weighing; the amount of water added during weighing is generally 2-3% (the actual weight after thawing must be no less than the specified weight); after weighing, place the prawns in clean prawn trays and attach 2 specification labels.

Tray arrangement: before arranging, the prawn trays should be cleaned and disinfected, ice water added to the tray, and the prawns arranged while washing, with the “neck” facing outward and the tails crossed, the lower layer with the back slanting downward and the upper layer with the back slanting upward, and the prawn bodies straight and flat. For those with fewer than 30 per pound, arrange in layers; for those with more than 31, arrange only in two layers, upper and lower. Any substandard prawns found during tray arrangement should be replaced immediately. After tray arrangement, attach one specification label each to the bottom layer and the surface layer, facing outward and centered flat.

Filling with water and draining: after the prawn trays are filled with clean ice water (below 6°C), immediately turn the tray over to drain; after draining, use stainless steel or plastic utensils to reshape so that the prawn bodies are closely packed and the surface is flat.

Semi-finished product inspection: the inspector draws no less than 5% of the samples for inspection of quality, specifications, weight and hygiene, and keeps a detailed record.

First water addition: before freezing, place a clean, hygienic pressure plate on each tray of prawns, then add ice water (about 4°C); the amount of water added is 1/3 of the prawn thickness; after adding water, use a utensil to draw a line along the inner wall of the prawn tray, then reshape.

Freezing: the plate freezer must be cleaned first, the freezing workshop temperature reduced in advance to below -20°C, and the product should be frozen in a freezing room below -25°C.

Second water addition: when the core temperature of the frozen product reaches -8°C, remove the pressure plate and add ice water (about 4°C); do not add too much water; continue freezing and cooling until the core temperature reaches below -15°C, and the time should preferably not exceed 13 hours.

Removal from freezing and demolding: when the core of the frozen product reaches below 15°C, it can be removed from freezing. Use the water-thawing method for demolding; the demolding water temperature must not be higher than 20°C, the time should be short and the movements quick, to prevent the ice from melting and affecting the appearance of the frozen block. Those with uneven block shape should be re-watered and frozen again, and frozen blocks with severe red bottom, mixed bottom or poor hygiene should be discarded.

Ice glazing: use the immersion method for ice glazing, to be carried out in a low-temperature storage (water temperature controlled at 0-4°C), for about 3 seconds.

Packaging: packaging materials must be clean and uncontaminated, and the packaging paper and labels that come into direct contact with the product must not contain fluorescent substances. Packaging materials need to be pre-cooled in a low-temperature room at -9°C.

Inspection of frozen products must be carried out before packaging, and packaging should be done in a low-temperature room (generally below -10°C). When packaging, fold the plastic bags tightly, cover the small cartons firmly, keep the box design orientation consistent when placing them in the box, and seal the large cartons with sodium silicate and adhesive tape.

Cold storage: the packaged finished products should be sent promptly to the cold storage for preservation (the cold storage temperature kept below -18°C), and foods with strong odors must not be stored at the same time. Prawn products should be stacked according to different grades, specifications and batch numbers, with a 30 cm gap between stacks, and the stack height must not exceed 3-3.5 m (13 boxes is suitable).

Finished product inspection: there is outer packaging inspection (whether the packaging is neat and firm), box-opening inspection (inspecting the temperature of the frozen block, the sealing of the plastic bags and the hygiene conditions) and thawing inspection (checking the quality, specifications, weight, etc. of the finished product).

Transit and consolidated transport: use refrigerated trucks and ships for transport; when the goods reach the transit warehouse, conduct sampling inspection at a ratio of 1% and measure the core temperature of the frozen product (below -8°C is considered qualified); if it is higher than -8°C, then thaw and inspect the quality.