CN100435657C - Method of improving comprehensive performance of vegetable paper - Google Patents

Abstract

The method of improving comprehensive performance of vegetable paper belongs to the field of fruit and vegetable food producing technology and is for mainly production of edible packing paper and paper type vegetable product. The vegetable paper producing process includes the steps of: sorting vegetable material, peeling, washing, slicing, scalding to deactivate enzyme, color protecting, mixing with moisture reducing agent and forming agent, pulping, deairing, forming, hot blast drying, microwave drying or infrared drying to water content of 20-30 %, peeling, cutting, further drying to water content of 10-20 %, and nitrogen filling or vacuum packing of the product. Owing to the moisture reducing agent and forming agent, the vegetable paper has good taste, relatively high tensile strength and breaking strength and may be eaten and used as the food packing material.

Description

A Method for Improving the Comprehensive Performance of Vegetable Paper

technical field

A method for improving the comprehensive performance of vegetable paper belongs to the technical field of fruit and vegetable food processing.

Background technique

Vegetables are rich in vitamins and cellulose. Vitamins are trace organic substances necessary for human growth and metabolism. Dietary fiber in cellulose can promote gastrointestinal motility, prevent constipation and maintain the health of the large intestine. At the same time, the rich cellulose in vegetables can also be used as a raw material for papermaking. Plastic packaging is usually used for food packaging, and some developed countries have partially restricted the use of plastic packaging because plastics are difficult to degrade naturally. Therefore, naturally degradable food packaging materials have become a research hotspot all over the world. Edible wrapping paper based on vegetable fiber can meet this requirement. Usually, the processing of vegetable paper is to add sucrose and salt to the vegetable pulp for seasoning, and then add some auxiliary materials to form a crispy leisure convenience food after drying. This kind of vegetable paper usually needs to be rehydrated again, and there are fewer varieties for direct consumption. There is also a flexible edible food packaging material that is formed by adding a binder to the vegetable pulp, but this type of product usually has a better paper feel, but the taste is poor. In order to improve the palatability of vegetable paper, it is generally to infiltrate or add some hydroxyl-rich carbohydrates in vegetables, and use its good water absorption to adjust the moisture content of vegetable paper to make vegetable paper have good palatability. However, since the addition of a large amount of sugar substances will affect the flavor of vegetable paper, this method is only used for a few special-purpose vegetable paper products. Some binders themselves are polysaccharides, and their rich carboxyl groups make them have high water absorption, which can not only bind free water but also act as a bridge between fibers, strengthen the bonding between fibers, and improve the strength of vegetable paper.

Patent CN1528184A uses the filter residue after tomato pressing as raw material, after adjusting the water content, adding molding agent and homogenizing treatment, the material is rolled into shape, and vacuum dried to obtain the finished product. Its forming agents include single or mixed agar, gelatin, guar gum, sodium carboxymethylcellulose and sodium alginate. Dry at 30-60°C, and control moisture so that the moisture content in the finished product is 6%-10%. The disadvantages of this processing method are: 1) the final product does not adjust the water activity, so the final product does not reach a safe moisture content, and it is difficult to store for a long time; Rot and deterioration occur; 3) the moisture content is low, the product is dry, tough and poor in palatability. The Japanese patent JP2002-45143A replaces the moisture in the vegetables by infiltrating the vegetables in the trehalose solution, and then breaks the vegetables into a film and drys them into shapes. It can well maintain the function of vegetable paper and has good palatability, but its application range is narrow, mainly used as a substitute for nori in traditional Japanese food.

Contents of the invention

The purpose of the invention is to provide a method for improving the comprehensive performance of vegetable paper, which is used for the production of edible wrapping paper and paper-shaped vegetables.

Technical solution: The present invention provides a method for improving the comprehensive performance of vegetable paper, the main process of which is to select, wash, slice, blanch, deenzyme and ripen (5-10min), color-protecting and other pretreatments of vegetable raw materials , drain until there are no obvious drops of water on the surface, mix with water activity reducing agent and forming agent, beat (3-5min), degas, lay flat in the mold to form, and then dry with hot air (60-80°C, 3-4h ), or microwave drying (60-80°C, 1700W, 5-10 minutes) or far-infrared drying (70-75°C, 2.5-3.0h) until the moisture content is 20-30%, peel off the slices and continue drying ( 40-60°C) until the moisture content is 10%-20%. The product is packed with nitrogen or vacuum. Because the present invention uses the water activity reducing agent, the water content of the vegetable paper can be 10% to 20%, and the water activity is 0.55 to 0.70. The vegetable paper has good palatability and can also ensure that the vegetable paper can be used for a long time (6-20%). The quality will not deteriorate significantly within 12 months), and the use of forming agent further improves the strength and flexibility of the vegetable paper, so that the thickness of the vegetable paper is 0.1mm-1mm, the tensile strength is 0.6-0.9kN/m, and the durability The folding degree is 95-110 times, which makes the vegetable paper not only edible but also used as wrapping paper.

The water activity reducing agent added in the present invention is salt, sucrose, glucose, lactose, fructose syrup, trehalose used alone or in combination, and the added amount is 5% to 15% of the wet weight of fruits and vegetables. CMC-Na, sodium alginate and agar are used as forming agents in the present invention, and can be used alone or in combination, and the addition amount is 0.1% to 0.5% of the wet weight of fruits and vegetables.

Sucrose, glucose, lactose, fructose syrup, and trehalose are relatively common monosaccharides and disaccharides, which can enter vegetable cells through osmosis, and their -OH combines with free water in or between vegetable cells to reduce the moisture content of vegetable paper activity. Table salt also has good permeability. It can dissociate into Na ⁺ and Cl ^- in water, and combine with polar water molecules by Coulomb force to reduce the water activity value of vegetable paper.

Usually the moisture content of vegetable paper is between 7% and 10%. In order to obtain a good taste, the general method is to add grain auxiliary materials to make the vegetable paper crispy, but this will reduce the mechanical properties of the vegetable paper. Packaging conditions are also subject to certain restrictions. By adjusting the water activity of the vegetable paper, combined with vacuum packaging or nitrogen-filled packaging, the vegetable paper has the characteristics of flexibility, firmness and dryness of intermediate moisture foods, and has certain safety, which can be stored for a long time.

The strength of vegetable paper is mainly determined by the bonding force between vegetable fibers. Among the binding forces of fibers, hydrogen bonds have the largest binding force and are the most important binding force. CMC-Na, sodium alginate, and agar are all polysaccharide biopolymers, with more carboxyl groups in their molecular structure and strong hydrophilicity, which can make fibers that are far apart and difficult to form hydrogen bonds rely on fiber-colloid-fiber The hydrogen bonds between fibers are connected to strengthen the bonding between fibers, thereby improving the mechanical properties of vegetable paper.

Beneficial effects of the present invention:

Compared with the background technology of vegetable paper processing with low moisture content, the advantages of the present invention are: 1) While increasing the moisture content of vegetable paper, the water activity can be kept at a safe level, improving the palatability and safety of vegetable paper 2) It improves the mechanical properties of the product and expands the application range of vegetable paper; 3) The drying time is short and the temperature is low, which can reduce the loss of heat-sensitive substances in vegetables and improve the nutritional value of vegetable paper; The limitation of product packaging and transportation conditions reduces the loss of products during transportation.

Compared with the technical background of colloid-added vegetable wrapping paper processing, the invention makes the wrapping vegetable paper edible, makes full use of the characteristics of vegetable fiber itself, improves the value of the vegetable paper, and expands the application range of the vegetable paper.

Detailed ways

Embodiment 1: take cabbage as the vegetable paper production of raw material

Select 250g of fresh cabbage, clean it, cut it into 5cm×5cm cubes, and blanch it in pH=7-8 water at a ratio of 1:20 for 5min at a blanching temperature of 96±2°C. Rinse in clean water to remove surface lye, place in 1500ml of zinc chloride solution with a concentration of 200mg/L for 5 minutes, and then rinse in clean water. Drain the surface water, add 13g of glucose and 2.5g of salt to treat at room temperature for 1h. After the treatment, put it in a beater, add 300mL of water and 0.25g of CMC-Na, the beating time is 4min, and the speed of the beater is 15000-10000 rpm. Put the slurry into a vacuum drying oven, and degas it for 5 minutes at a vacuum degree of 0.09MPa. Spread the slurry evenly in the mold at an amount of 4400g/ ^m2 , dry with hot air at 80°C for 1.5h, then continue to dry with hot air at 60°C for 2h, peel off the sheet, and cut into rectangles, circles and other shapes of various specifications , and continue to dry until the surface does not feel wet to the touch (about 15-30min). After taking it out and cooling to room temperature, it is graded and vacuum-packed and stored according to various specifications. The obtained vegetable paper has a thickness of 0.1mm, a tensile strength of 0.9kN/m, a folding endurance of 95 times, a moisture content of 10%, and a water activity of 0.55.

Embodiment 2: take hot-air drying (AD) vegetable core as the vegetable paper production of raw material

Weigh 50g AD cabbage core, rehydrate 7mm in 1000ml rehydration solution with pH=7-8, and the rehydration temperature is 96±2°C. Rinse in clean water to remove surface lye, place in 1500ml of 200mg/L zinc acetate solution for cold immersion for 5min, and then rinse in clean water. Drain the surface water, add 10g fructose syrup and 2.0g salt and marinate at room temperature for 1h. After pickling, put it in a beater, add 300mL of water and 0.20g of sodium alginate, beat for 5 minutes, and the speed of the machine is 10000-15000 rpm. Put the slurry into a vacuum drying oven, and degas it for 5 minutes at a vacuum degree of 0.09MPa. Spread the slurry evenly in the mold at an amount of 4246g/ ^m2 , dry with hot air at 80°C for 1.5h, then continue to dry with hot air at 60°C for 2h, peel off the sheet, and cut into rectangles, circles and other shapes of various specifications , and continue to dry until the surface does not feel wet to the touch (about 15-30min). After taking it out and cooling to room temperature, it is graded and vacuum-packed and stored according to various specifications. The obtained vegetable paper has a thickness of 0.5mm, a tensile strength of 0.75kN/m, a folding endurance of 105 times, a moisture content of 15%, and a water activity of 0.62.

Embodiment 3: the production of the vegetable paper that is raw material with cabbage juice processing leftover cabbage slag

Weigh 500g of cabbage pomace, cook in 2500mL of 30% sucrose + 1% salt solution at 100°C for 3min, remove and cool to room temperature, put in a beater, add 800mL of water and 0.5g of sodium alginate (dissolved in water) , the beating time is 4min, and the machine speed is 10000-15000 rpm. Put the slurry into a vacuum drying oven, and degas it for 5 minutes at a vacuum degree of 0.09MPa. Spread the slurry evenly in the mold at an amount of 4500g/ ^m2 , dry in the far infrared (70-75°C) for 2.5 hours, peel off the sheet, cut into rectangles, circles and other shapes of various specifications, and continue to dry until the surface touches No wet feeling (about 10-15 minutes). After taking it out and cooling to room temperature, it is graded and vacuum-packed and stored according to various specifications. The obtained vegetable paper has a thickness of 1mm, a tensile strength of 0.6kN/m, a folding endurance of 110 times, a moisture content of 20%, and a water activity of 0.70.

Claims (2)

1. A method for improving the comprehensive performance of vegetable paper. First, vegetable raw materials are selected, washed, sliced, blanched to eliminate enzymes, and color-protected after pretreatment. It is characterized in that the pretreated vegetables are mixed with an appropriate amount of water activity reducing agent and Forming agent mixing, beating, degassing, molding, hot air drying, or microwave drying, or far infrared drying to a moisture content of 20% to 30%, peeling off the slices and continuing to dry until the moisture content is 10% to 20% , the product vegetable paper is packed with nitrogen or vacuum; The water activity reducing agent is a single or mixed component of salt, sucrose, glucose, lactose, fructose syrup, and trehalose, and the added amount is 5% to 15% of the wet weight of the vegetable raw material; The forming agent is a single or mixed component of sodium carboxymethyl cellulose, sodium alginate and agar, and the added amount is 0.1% to 0.5% of the wet weight of vegetable raw materials. 2. The method according to claim 1, characterized in that hot air drying: 60-80°C, 3-4 hours; or microwave drying: 60-80°C, 1700W, 5-10 minutes; or far-infrared drying: 70- 75°C, the drying time is 2.5~3.0h.