Study On Analysis Of Active Ingredients In Thymus Quinquecostatus Celak And The Fermentation Technology Of Its Residue

Thymus quinquecostatus Celak,as known as ground pepper and mountain pepper,is the whole grass of the aromatic plant thyme,because of its unique aroma,it has been widely used as a flavoring condiment since ancient times,especially popular in western countries.Thymus quinquecostatus has antibacterial,anti-inflammatory,anti-tumor,anti-oxidation,anti-aging,and beauty effects,volatile compounds and flavonoids are considered to be the key substances for its medicinal effects.There are abundant Thymus quinquecostatus resources in Yulin area,which has great development and utilization value.However,the deep processing of Thymus quinquecostatus products is quite lagging behind.The variety of related active ingredient products of Thymus quinquecostatus is scarce,and there is no sustainable development and utilization of Thymus quinquecostatus resources.Therefore,an in-depth analysis of the active ingredients of Thymus quinquecostatus and the development of high-yield Thymus quinquecostatus active ingredient products can deeply explore the potential value of Thymus quinquecostatus,and it can also bring huge economic benefits,which is of great significance to the promotion of local economic development.The main conclusions of this article are as follows:(1)Analysis of volatile components of Thymus quinquecostatus.Analysis of volatile substances in Thymus quinquecostatus flowers and leaves by GC-IMS technology.A total of 72 volatile substances were detected and 36 volatile constituents were qualitatively identified,including 8 alcohols,6 aldehydes,6 ketones,6 terpenes and their derivatives,5 esters,3 acids and 2 heterocyclics.The volatile organic compounds between Thymus quinquecostatus flowers and leaves are compared by GC-IMS fingerprinting method,the results show that the overall types of volatile substances in all samples are similar,however,the content of volatile substances in leaves is generally higher than that in flowers.Among them,Thymus quinquecostatus flowers and leaves generally contain some alcohols,aldehydes and a small amount of esters.The leaves of Thymus quinquecostatus mainly contain some terpenoids and their derivatives,such as limonene,linalool,?-terpineol,y-terpinene and other substances.Some acids and heterocyclic substances are mainly distributed in Thymus quinquecostatus flowers,such as propionic acid and 2-ethylfuran.At the same time,the standard curve method was used for quantitative analysis of thymol.The test results showed that the content of thymol was the highest in May leaves.(2)Study on optimization of extraction technology of total flavonoids in Thymus quinquecostatus.The optimal extraction process for total flavonoids from Thymus quinquecostatus was optimized by response surface test.The test results show that the fixed ultrasonic power is 200 W,the liquid-to-material ratio is 35:1(mL/g),the volume fraction of ethanol is 63%,and the ultrasonic extraction is performed for 40 min at 65?.Three parallel experiments were performed under the optimal process conditions.The actual average of the total flavonoid yield of Thymus quinquecostatus was 4.28±0.08%,and the relative error from the theoretical value is 2.6%,which proves that the ultrasonic-assisted extraction of ground pepper flavone by response surface method is reasonable and effective.(3)Study on antioxidant activity of the total flavonoids in Thymus quinquecostatus.The ultrasonic-assisted extraction of the total flavonoids from Thymus quinquecostatus were evaluated for antioxidant activity.The results showed that the total flavonoids from Thymus quinquecostatus had good antioxidant activity.Its DPPH free radical,ABTS free radical and hydroxyl free radical scavenging rates reached 95.3±0.9%,87.9±0.7%and 57.4±0.5%,respectively,which can provide a technical reference for the in-depth excavation and full utilization of the potential value of Thymus quinquecostatus resources.(4)Study on the fermentation technology of Thymus quinquecostatus residue.The Response surface optimization was used to optimize the fermentation technology of Thymus quinquecostatus fermented beverages.The sensory score and pH value were used to evaluate the fermentation effect.The effects of fermentation parameters such as inoculum amount,fermentation time,and fructose syrup on the sensory quality of beverages were studied.The test results show that the three factors have significant effects on the sensory scores,and their contribution to the sensory scores are as follows:the amount of inoculation>the amount of fructose syrup added>fermentation time.The best fermentation process of Thymus quinquecostatus beverage is:fructose syrup was added at an amount of 8.0%,0.7%of lactic acid bacteria were inoculated,and fermentation was performed for 17.5h at 42?.Under the conditions of this process,the product with the characteristic aroma of Thymus quinquecostatus,moderate sourness and sweetness,and smooth taste.