Processing technology of wort fermented beverage

Barley (HordeumluvgareL.), alias barley, rice wheat, naked wheat and so on, belongs to Gramineae. It ranks fourth in yield among food crops in the world, only second to @ # @ 245 wheat, rice and corn. It is widely used in food, feed, brewing, medicine, textile, nuclear industry, weaving technology and so on. Germination treatment can not only improve the nutritional value of grain seeds, increase the digestible absorption rate of protein and starch, increase the content of restricted amino acids and vitamins, but also reduce toxic, harmful and some anti-nutritional components. At present, the popular lactic acid fermented beverage in China is traditional yoghurt, and in recent years, there are research reports on the production of lactic acid fermented beverage with vegetable juice. However, due to the strong seasonality of raw materials, no product has been put on the market. This paper introduces a kind of lactic acid fermented beverage which uses barley with low price and rich source as the main raw material, which not only increases the new varieties of beverage. It also opens up a development prospect for the application of biotechnology in the deep processing of agricultural products, and opens up a new way for grain transformation and value-added.

I. technological process

Barley → impregnated → germinated → dried → crushed → saccharified → wort → mixed with excipients → homogenized → sterilized → inoculated → aseptic filling → fermentation → after ripe → test → products.

2. Key points of operation

1. Preparation of wort. The saccharification process of secondary boiling method was adopted, and the ratio of adding water was 1:6 (W / W). First, rest the protein for 1 hour at 50 ℃-52 ℃, then boil 1/3 mash for 5 minutes, then mix with the remaining 2/3 mash, set the temperature to 63 ℃-65 ℃, and keep saccharification until the iodine solution does not change color, that is, the saccharification is complete. The saccharification time depends on the quality of malt. The mash with complete saccharification was separated into liquid and dense phase, and the latter was heated to 72 ℃-73 ℃, kept for 10 minutes, then boiled, and then mixed with the liquid part to keep the temperature of the liquid at 75 ℃-78 ℃ for 5 minutes. 78 ℃ was filtered by heat to get the original wort. The wort is boiled and kept boiling for a certain period of time in order to control the boiling intensity required by the process and remove coagulant β-globulin.

2. Add auxiliary materials to mix. The wort from the saccharification of 10kg barley is diluted to 100kg with sterile water, adding 10% fresh milk (milk powder is also OK, milk powder is 7 times water to get milk), 5% lactose, 5% white sugar (sugar solution is pre-dissolved and filtered), 0.5% Agar (dissolved). Stir well.

3. Homogenization. It is treated by high pressure homogenizer, and the average pressure is above 18MPa. Or use colloid mill to homogenize for 5 minutes.

4. Sterilization. Heating at 95 ℃-100 ℃ for 2 minutes, plate heat exchanger can be used for sterilization. Then quickly cooled to 40 ℃.

5. Treatment and preparation of starter.

The starters used in this experiment are Lactobacillus bulgaricus and Streptococcus thermophilus.

The main results are as follows: (1) preparation of skim milk medium. 20g skim milk was put into sterilized dry 250ml flask and 18x180mm test tube respectively and sterilized in high pressure sterilizer 0.1Mpa and 121℃ for 15 minutes. When dissolved, the weight ratio of skim milk powder: raw wort = 1:8, fully stirred and cooled to 41 ℃, then inoculated and cultured.

(2) strain activation and culture. After high pressure sterilization, skim milk-raw wort was used as culture medium for seed culture and expanded culture. The seed medium was sterilized at 110 ℃ for 30 minutes, then cooled rapidly to 42 ℃, and the expanded medium was sterilized at 95 ℃ for 30 minutes, rapidly cooled to 40 ℃, then inoculated in clean flasks and test tubes containing sterilized milk to keep the ratio of Lactobacillus bulgaricus to Streptococcus thermophilus at 1:1 and sealed with sterilized clean cotton balls. Then activated culture was carried out in a 42 ℃ constant temperature incubator for about 12 hours until solidification. After being taken out and placed under 5 ℃ for about 24 hours, the flavor substance was improved, and then activated for the second and third times, so that the strain could meet the requirements of this experiment.

6. Vaccination. The domesticated Lactobacillus bulgaricus and Streptococcus thermophilus were inoculated in the mixture at the proportion of 2% Murray 3%, and homogenized.

7. Aseptic filling, fermentation and ripening. Under aseptic conditions, it was sub-packed in sterilized bottles and sealed, and sent to the heat preservation room for fermentation and culture. The fermentation temperature is about 40 ℃ and the fermentation time is 6 hours. When the culture reaches a certain acidity, it can be sent to cold storage for post-ripening at low temperature. Post-ripening conditions: temperature 0 ℃-4 ℃, time 10 Murray 12 hours, pH 4.1 Murray 4.2.

8. Check the finished product. According to the sensory index, physical and chemical index and microbiological index of the product, it can be packed and left the factory after it is qualified.

III. Product quality indicators

1. Sensory indicators. Color: uniform, slightly yellowish.

Taste and smell: moderate sweet and sour, with obvious barley flavor and lactic acid bacteria fermented beverage unique fragrance, pure lactic acid taste, no peculiar smell and miscellaneous smell.

Tissue status: delicate taste, showing emulsion, uniform and undivided, with a small amount of precipitation allowed.

2. Physical and chemical indexes. Soluble solids ≥ 10.0%; protein ≥ 3.2%; fat ≥ 1.0%; acidity (in terms of lactic acid) 0.63% Murray 0.95%. Lead (in Pb), ≤ (0.5mg), ≤ (in As), and copper (in Cu), ≤ 1mg/kg.

3. Microbiological index

The total number of bacteria ≤ 100cfuqml; coliform group ≤ 3cfuqml; pathogenic bacteria should not be detected.