Technology And Quality Evaluation Of A Vinegar Product Fermented With Eucommia Ulmoides Leaves

Recent studies show that leaves from Eucommla ulmoides, an important edible and medical tree in traditional Chinese medicine have such bioactive ingredients as those of its barks. Unlike its barks, the leaves of Eucommia ulmoides easily are harvested each year. The worse thing is that peal of its bark often cause the tree to die, reducing its population. Crop vinegar is popular Chinese brewing product with good market. This study is aiming at developing a new type of vinegar made with Eucommia ulmoides leaves. It includes3issues. The first is the development of eucommia-leaves vinegar technology. The second deals with the stability of eucommia-leaves vinegar technology via fingerprint analysis. The third evaluates the quality of the final eucommia-leaves vinegar product according to antioxidant activity, flavor and sensory assay. The objective of the present study should be helpful for the integrated and long-term utilization of eucommia resources. The following are main results.(1) Release level of chlorogenic acids from leaves was used to evaluate the quality of the eucommia-leave fermented vinegar. Eucommia leaves mixed with water were firstly pretreated by cellulose enzyme45℃for2h. The ratio of powdered eucommia leaves to water was1:10, and the ratio of the total dry weight of eucommia leaves to the enzyme amounted to0.8%. In this case, the level of chlorogenic acids released reached592.1μg/mL after2h-incubation at45℃.1:1of eucommia leaves hydrolysates to bran was mixed, and then the eucommia-hydrolysates bran mixture was blended with water by1:7of solid-liquid ratio, with a10%of glucose supplement and1%pre-culture for alcohol fermentation, and14%strain AS.141for subsequent acetic acid fermentation. Fermentation stopped after8days when acetic acid level was4.9g/100mL.(2) Use of chlorogenic acids fingerprint to describe the technology stability of the eucommia-leaves fermented vinegar was carried out.5batches of eucommia-leaves vinegar were sampled and verified to have good similarity (higher than0.9) between the products from Lab-scale and those from pilot-scale. In the case of plant-scale, chlorogenic acid from the eucommia-leaves fermented vinegar was102.3μg/mL, and acetic acid6.5g/100mL.Itmeans that the production processing should be stability.(3) Eucommia-leaves vinegar products in sensory, flavor and hygiene meet the requirements of national standard very well. Importantly, they show good DPPH free radical-scavenging (97.27%).10mg/mL of the fermented vinegar invitro inhibited82.55%platelet to aggregate in blood. The eucommia-leaves fermented vinegar not only has good anti-coagulation effect of blood, but does not destroy the morphology of blood cells as well.