Black Garlic Liquid Fermentation Process

Black garlic is a deep processing product of garlic which is formed by ripe fresh garlic under high temperature and high humidity conditions for a long time.The hot processing technology of black garlic not only removes the spicy taste and garlic odor of raw garlic,but also makes the black garlic taste soft and sweet and taste better and richer in nutritional value,and it gradually becomes a popular health food which is popular among the public.At present,the production of black garlic is mainly carried out by solid-state fermentation of garlic or garlic cloves with large heads,full particles and no mechanical damage.However,this fermentation processing has several disadvantages,such raw materials wasting,some small garlic and broken garlic cannot be used.Liquid fermentation not only overcomes the above problems of solid-state fermentation,but also has the advantages of easier control of fermentation conditions,high yield,and energy saving.This paper uses the broken petals or small garlic in Laiwu garlic as raw materials to study the effects of material-liquid ratios,temperatures and other process conditions on the liquid fermentation of black garlic to meet the production requirements.The process parameters of black garlic liquid fermentation were determined,and the flavor substances and energy consumption under the process conditions were analyzed.The research results have great significance for guiding the production of black garlic.The main findings of this experiment are as follows:1.Effect of different material-to-liquid ratios on the quality of liquid fermented black garlicGarlic mud was prepared by hot processing under different conditions of liquid to liquid.By monitoring the main quality indexes such as reducing sugar,5-HMF,total phenol and amino nitrogen in the process of black garlic heating,the ratio of different liquid to black was analyzed.The results show that the lower moisture content in the ratio of material to liquid,the shorter time required for the formation of black garlic.Increasing the proper water in the garlic is more conducive to the accumulation of reducing sugar,total acid and polyphenol in black garlic.Combined with the sensory evaluation,the optimum ratio of material to liquid for garlic fermentation is 5:2.The content of reducing sugar in the fermented mature black garlic is 1.4-2.5 times that of other materials and liquids.The polyphenol content was 13.26 g/kg,and the total acid was about 35 g/kg.At this time,the quality of black garlic was the best.2.Effect of different temperature on the quality of liquid fermented black garlicThe garlic puree was fermented under different temperature conditions.The main quality indexes such as reducing sugar,5-HMF,total phenol and amino nitrogen were monitored during the heating process of black garlic.The effects of different temperatures on the quality of black garlic were analyzed.The results showed that the speed of black garlic formation was affected by temperature.The higher the temperature,the faster the changes of garlic index,but the excessive temperature would affect the formation of sensory quality of black garlic.Under the temperature conditions,the content of reducing sugar in mature black garlic was higher and the sweetness was better.The total phenolic content in mature black garlic at 80°C and 90°C was1.68 and 2.21 times of total phenolic content of black garlic at 70°C;mature black at 90°C The content of total acid and 5-HMF in garlic affected the taste of black garlic.The content of5-HMF and total acid in mature black garlic at 80°C was within a reasonable range,and the taste of black garlic was better.According to comprehensive analysis,when the temperature is80°C,the mature black garlic has the best sensory quality and functional quality.3.Effect of liquid fermentation on volatile flavor substancesA comparative analysis of the volatile substances of fresh garlic and liquid fermented black garlic shows that the types and contents of the flavor substances of the three are quite different.The hot processing of garlic mud converts volatile sulphur compounds with pungent and spicy taste into fragrant components such as thiophene and furan in black garlic,which increases the aroma of black garlic and imparts sensory quality to black garlic.The flavor of liquid fermented black garlic is superior to that of traditional fermented black garlic.4.Comparison of energy consumption between liquid fermentation and solid state fermentationBy controlling the same fermentation conditions,black garlic obtained by the liquid fermentation process can save 3.7×10~5 J energy per kilogram compared with the solid fermented black garlic.If 1 ton of garlic is produced,about 3.7×10~8 J is saved,indicating that liquid fermented black garlic has the advantage of lower energy consumption.