Active Dry Yeast

Active dry yeast is quite common in our daily life. When we make some pasta, we often use some active dry yeast. These active yeasts are fresh yeasts that can still maintain a relatively good fermentation effect after being squeezed, dried and dehydrated. Active dry yeast is often used when making dough. Let us learn about some content about active dry yeast.

Introduction

The application in the preparation of active dry yeast cells requires that the protein content be controlled at 40%~45%, while the carbohydrate content, especially trehalose, must be high. Since the 1970s, genetic engineering and modern drying technology have been used to make instant active dry yeast, also known as highly active dry yeast. Compared with active dry yeast, it contains 4% to 6% moisture, has smaller particles, and ferments faster. It does not require pre-hydration and can be used directly. Most of the current products are active dry yeast, including active dry yeast for bread, alcohol and wine.

Process Introduction

The production of active dry yeast uses starch or waste honey from sugar factories as raw materials, mixed with nitrogen-containing chemicals such as ammonium sulfate and urea, and is disinfected, introduced with sterile air, cultured at a constant temperature, and expanded step by step. The yeast mud is collected, granulated, and dried in a low-temperature boiling drying bed or a fluidized drying bed to obtain the finished product, which is vacuum-packed with aluminum-plastic film into specifications such as 500g/bag, 100g/bag, 30g/bag, and 10g/bag and put on the market with a shelf life (shelf life) of one year.

Active dry yeast production process flow chart

Laboratory → pure culture → seed culture → commercial yeast culture → centrifuge separation → yeast milk refrigeration → pressing → fresh yeast → granulation → drying → packaging → warehousing

The main raw materials for producing active dry yeast are molasses (a waste liquid from sugar factories) or sugar solution made from starch (corn, potatoes, sweet potatoes, cassava), plus chemical raw materials such as ammonium sulfate, urea, and ammonium phosphate. The energy required is steam and electricity.

Conditional Analysis

①Built in areas with starch or molasses resources. Starch can be from corn, cassava, potato, sweet potato, and other resources. Molasses can be either cane molasses or beet molasses.

②Places where energy is relatively cheap. It would be best to have a thermal power station, which can reduce investment and is cheap, and is located in places with abundant hydropower or coal-producing areas. Because building an active yeast plant with an annual output of 2,000 tons requires about one 1000KVA transformer and one 8-ton boiler.

③The best regional distribution is in the northwest or southwest. Currently, yeast factories are mainly concentrated in the southeast coast, where energy is tight and costs are high. Development towards the northwest and southwest can promote deep processing of local agriculture and food industries. There is broad market space in the southwest and northwest.

④ Suitable scale: In the initial stage of plant construction, it is advisable to build an annual output of 2,000 tons, and then expand it after it stabilizes. The investment for a 2,000-ton scale is about RMB 30 million, excluding technology transfer fees. It covers an area of ​​about 20 acres and has a construction area of ​​about 7,000m2.

⑤ Environmental protection: Wastewater can be used to irrigate farmland, or it can be biochemically treated to meet discharge standards.