Application of spray drying in food industry

 Application of spray drying in food industry

At this stage, the most commonly used drying method in food processing is spray drying technology. During spray drying, the main influencing factors are the degree of homogeneity of the material before spray drying, the inlet and outlet temperatures during drying, and the pressure of the feed pump. There are other influencing factors, such as the ratio of sugar to acid, temperature of material and liquid, and feed flow rate during spraying, which will have certain influence on the yield and solubility of the product.

Lab scale spray dryer has been widely used in the processing of nutritional food for infants and young children, the processing of various grain and fruit powders, the processing of microcapsules of functional products such as fish oil and protein powder, the processing of instant tea beverages, and the processing of condiments and other food industries. The following examples introduce the application of spray dryer machine in the food industry:

Drying of proteins in the food industry:

Protein is an essential nutrient for the human body, and it is necessary to pay attention to the intake of protein foods in the diet. Although animal protein is the main source of food protein, due to its high cost and potential food safety risks such as hormone and antibiotic residues, research on plant protein resources has received more and more attention. Lotus seeds are rich in protein, amino acids, unsaturated fatty acids and minerals, and also contain functional substances such as water-soluble polysaccharides, polyphenols, lotus seed flavonoids, and alkaloids, so lotus seeds have high nutritional and health care value.

The protein content of lotus seeds is about 19.0%, which is much higher than that of fresh chestnut, ginkgo, and water chestnut, which are also hard fruits. Therefore, for lotus seeds, in addition to its special medicinal ingredients, its nutrition, edible quality and processing performance The most important thing is protein. Protein in food is not only an important factor affecting food nutrition, but also an important factor affecting its processing performance, and a large number of studies have shown that the structure and functional properties of protein are not only related to the source of protein, but also affected by the drying method of protein. Different drying methods will affect the physicochemical and structural properties of proteins, thereby affecting the quality of proteins. Spray drying and freeze drying are currently commonly used protein drying methods. Spray drying is a drying process in which the raw material liquid is dispersed into droplets with an atomizer, and a powder product is obtained by direct contact of hot air with the droplets. It has the characteristics of rapid drying, simplified production process, simple operation, and good dispersibility and fluidity of the product.

The extraction method of lotus seed protein:

1. Crush the cored lotus seeds, put them in a jar, and store at 4 ℃.

2. Set the injection temperature to 170 °C, the feed rate to be 15%, and the fixed hot air flow rate to be 25 m3/h. The lotus seed protein is dried under this condition.

3. After drying, collect dried lotus seed protein in a collector and store at 4°C for later use.

Advantages of spray drying for protein extraction:

1. Quick drying to ensure product quality. Food contains more protein and sugar, and protein generally denatures when kept at 60-80°C for several minutes. Using spray drying, the product can be dried in only 3~10s, which can effectively inhibit the thermal denaturation of the food and the loss of aromatic components during the drying process, and ensure the quality of the product.

2. The dry product has good dispersibility, fluidity and solubility. For dry products, dispersibility, fluidity and solubility are important indicators of product quality. In the process of spray drying, the drying of the product is carried out in hot air, so the product can basically maintain a spherical shape similar to the droplet, so it has good dispersibility, fluidity and solubility.

3. The production process is simplified, the operation and control are convenient, and it is suitable for continuous large-scale production. Most of the products obtained by spray drying do not need to be pulverized and screened, thus reducing the production process and simplifying the production process. The particle size, bulk density and water content of the product can be adjusted by changing the operating conditions within a certain range, the control and management are very convenient, and it can meet the requirements of industrialized large-scale production.

4. Prevent pollution and improve the production environment. Spray drying is carried out in a closed container, which can avoid dust flying during the drying process and avoid environmental pollution.

Examples of common food additive materials that can be dried:

Preservatives – commonly used are sodium benzoate, potassium sorbate, sulfur dioxide, lactic acid, etc. It is used in food processing such as jam and preserves.

Antioxidants – Similar to preservatives, they extend the shelf life of foods. Commonly used are vitamin C, different-dimensional C and so on.

Colorants – Commonly used synthetic pigments are carmine, amaranth, tartrazine, indigo, etc. It changes the appearance of food and makes it more appetite.

Thickeners and stabilizers – can improve or stabilize the physical properties of cold food products, making the food appearance smooth and delicate. They keep frozen foods such as ice cream soft and loose for long periods of time.

Raising agent – some candies and chocolates are added with a raising agent, which can promote the production of carbon dioxide in the sugar body, so as to play a bulking role. Commonly used leavening agents include sodium bicarbonate, ammonium bicarbonate, compound leavening agents, etc.

Sweeteners – commonly used synthetic sweeteners are sodium saccharin, sodium cyclamate, etc. The purpose is to increase the sweetness.

Acidulants – Some beverages, candies, etc. often use acidulants to adjust and improve the flavor effect. Commonly used citric acid, tartaric acid, malic acid, lactic acid and so on.

Description-The main ingredient in kneading the dough is benzol oxide. The upper limit of food intake for flour is 0.06 g / kg, and the baking agent extracts food from the flour and dissolves benzoic acid to produce hydrogen peroxide. food. Benzene oxide is banned as food waste in developing countries such as the European Union, and in May 2011 my country banned benzene peroxide as a limiting agent.


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