Extraction And Component Identification Of Tea Saponin From Camellia Meal And Its Application In Strawberry Preservation

Camellia oleifera, an unique woody oil plant in China, is widely planted in Southwest of China. China has the highest annual production of Camellia seed. Camellia oil can be obtained after squeezing Camellia seed, which is a kind of high quality edible oil with a reputation of oriental olive oil. But its byproduct-Camellia meal, is either used as fertilizer or feed with low effect because the bitter and spicy tea saponin has toxic effects on cold-blooded animals. Usually, it is used as clear agent to spread directly to ponds, or as rubbish to pile up with an extreme low value, even causing pollution due to mildew. Camellia meal contains many active ingredients, such as tea saponin, flavonoids, and so on, which has a great potential value. In this study, Camellia meal was subjected to extraction and purification, and the components and properties of tea saponin as well as its application in strawberry preservation process were investigated. The main results are listed as follows:(1) The exploration of extraction methods and conditions for tea saponin. Tea saponin was isolated from Camellia meal by conventional maceration and microwave-assisted extraction methods in three different solvents (ethanol, propyl alcohol, and water). The properties of all the samples, such as thermal behavior, foaming property, emulsifying property, antioxidant, and surface tension, were tested to find the best extraction method. The results showed that the sample obtained by microwave extraction in ethanol had the highest yield and purity, the best thermostability, the lowest CMC value and the strongest foaming and emulsifying properties.(2) Establishing the best extraction and purification methods for tea saponin. The optimal extraction parameters were solid to liquid ratio 1:13, ethanol concentration 65% (v/v), microwave power 700 W, and time 5 min. The best purification method was using n-butyl alcohol solution saturated with water to dissolve the samples many times, collecting all the filtrates and rotary evaporating to dry, then using acetone to wash out the solid. The yield and purification of the sample were 4.5% and 72.7%, respectively.(3) Qualitative and quantitative analysis of the main active ingredients of the purified sample. By using UPLC-MS to authenticate the saponin species and its content,25 saponins and their relative contents were identified. By using HPLC to authenticate the flavonoid species,5 flavonoids and their contents were identified.(4) Preservation test of strawberry after soaked in fresh-keeping liquor with the purified sample. After strawberry was processed under different conditions, the rotting rate, weight loss ratio, Vc content, total acid content, hardness and sugar content of strawberry were tested. The results showed that the effect of the treatment at a low temperature was better than that at room temperature, that the effect of fresh-keeping liquor was better than that of deionized water, and that the preservation effect increased with the increase of fresh-keeping liquor concentration.