Effects Of Humidity On The Quality Of Black Garlic

Black garlic is made from garlic under the condition of high temperature and humidity.It not only removes the pungent smell of garlic,but also has high nutrition and health care function Humidity is the key parameter of black garlic processing technology,which affects the formation and quality of black garlic.In this study,garlic was processed to black garlic at humidity of 70%,80%,90%,98%,as well as 12 kinds of humidity combinations.Moisture,browning degree,hardness,reducing sugar,polyphenol,hydroxymethyl furfural(HMF),amino nitrogen,total acid and other substances were determined during processing of various humidity.And analyzing flavor and sensory evaluation of black garlic.These results might contribute to our understanding the role of humidity in the quality formation of black garlic.The main results were as follows:1.Effects of humidity on the quality of black garlicThis study investigated effect of humidity on the quality of black garlic.Fresh garlic was processed to black garlic and quality indicators were determined during the process of different humidity.The higher the humidity,the higher the content of moisture,reducing sugar,amino acid nitrogen,HMF and polyphenol,and the lower the total acid,browning degree and hardness.When the black garlic is ripe,the degree of browning of garlic is about 73,and the lower the humidity is,the shorter the time is needed.In the whole process,the content of moisture and amino acid nitrogen decreased,and the content of reducing sugar and total phenol first increased and then decreased,and the HMF,total acid and browning degree increased.2.Effects of humidity on volatile flavor compounds of black garlicCompared volatile flavor compounds between fresh garlic and black garlic of different humidity conditions,it is different that species and contents of volatile flavor compounds between fresh garlic and black garlic.There are 27 kinds of volatile compounds in garlic,and the volatile components in different black garlic are: 23,25,23,and 22.Stimulating flavor compounds content of black garlic was decreased,its fragrant flavor compounds content was increased.There was HMF and melanoid generating in black garlic,but not in fresh garlic,so black garlic is black color.The varieties and contents of volatile flavor compounds of black garlic were different in order that quality of black garlic was varied.3.Effects of humidity on the quality of black garlicUnder the condition of 80 oC,the humidity condition of black garlic is 70%~98%,and the mature time is about 12 days.Black garlic quality has great difference in different humidity,the formation of low and high humidity is not conducive to the quality of black garlic.Based on the comprehensive analysis of flavor,appearance,nutrition,function and quality evaluation,the best quality of black garlic was formed by 80%.4.Effects of humidity on the appearance quality of black garlicThe color of black garlic skin affects the appearance quality of black garlic.The greater the humidity,the deeper the color of garlic skin.The smaller the humidity,the lighter the color of garlic skin.During processing,the content of moisture,reducing sugar,amino acid nitrogen and other substances in garlic were transferred to the garlic skin.In addition,the study showed that the garlic skin contains polyphenols,which has antioxidant activity.5.Effects of variable humidity treatment on processing technology and quality of black garlicBased on the single-factor test of humidity experiment,garlic was ripened at various humidity combinations.The variable humidity treatment can improve the quality of black garlic,shorten the processing time and save energy.The quality of 12 different combinations of black garlic was analyzed comprehensively.The optimum technological conditions were shown below: 90%: 4d;80%~90%: 4d;80%: 4d;70% : 0~4d.