| In order to effectively exploit hovenia seeds and further develop nutritional and functional properties of hovenia seeds, physical properties and nutrient content of hovenia seeds were analyzed; Response surface methodology was applied to optimize the ultrasonic extraction conditions of total flavonoids in hovenia seeds; The lipid antioxidant activity of the crude extract and the in vitro antioxidant activity of crude extracts and the refined extracts were studied and analyzed. Main results as follows:The three-dimensional sizes of hovenia seeds was (4.05±0.30mm)×(3.66±0.34mm)×(1.82±0.24mm). Thousand seeds weight was 16.88±0.06g. Rate of kernel contents was 45.66±2.75%. Bulk density was 765.17±16.83g/L. Angle of repose was 25.63±0.80°. Angle of slide was 20.83±1.04°. Main components of hovenia seeds: water 8.81±0.13%, protein 15.79±0.08%, fat 8.03±0.08%, ash 2.08±0.02%, starch 0.61±0.01%. Among amino acids, essential amino acids account was 29.1%. Among Ash, constant elements (potassium, magnesium, calcium, sodium) account was 98.7%, trace elements (iron, manganese, copper, zinc) account was 1.3%. Contents of linolenic acid, oleic acid and linoleic acid in oil of hovenia seeds is high, and the relative content of linolenic acid as high as 45.56%.The results of optimizing conditions of ultrasonic extraction of total flavonoids in hovenia seeds by using response surface methodology as follows: Under the condition ( the temperature was 65℃and extraction time was 60min), the order of main influencing factors on the extraction rate was concentration of ethanol, ratio of solvent to material and ultrasonic power; The optimum ultrasonic extraction conditions were as follow: the ultrasonic power was 374.4W, ratio of solvent to material is 69.42mL?g-1, concentration of ethanol was 64.46%. The yield of total flavonoids in verification experiment was reached 0.819±0.003%, close to the predictive value of 0.823%. Regression model showed good predictive ability.Lard was raw material, using oven method to evaluate the lipids antioxidant properties of different concentrations of the crude extract of total flavonoids in hovenia seeds and compare them with L-Ascorbyl 6-palmitate, vitamin E, tertiary butylhydroquinone (TBHQ). The results showed that in the oxidation induction period of lard, the oil antioxidant capacity of the 0.1% crude extracts of total flavonoids and the 0.02% TBHQ was very similar, indicating that the lipids antioxidant properties of the crude extract of total flavonoids in hovenia seeds was strong.With the total reducing capacity, the O2-·scavenging effect, the DPPH·scavenging effect and the nitrite scavenging effect as the in vitro antioxidant activity index, the in vitro antioxidant activities of the same concentration of the crude extract of total flavonoids, the refined extract of total flavonoids, ascorbic acid and citric acid were compared and analyzed, results as follows: the order of the total reducing capacity was ascorbic acid, the refined extract, the crude extract, citric acid. The total reducing capacity of the refined extract was slightly greater than the crude extract, and with the dosage increased, the gap also increased. The order of the O2-·scavenging effect was ascorbic acid, citric acid, the refined extract, the crude extracts. The O2-·scavenging effect of the refined extract was similar to citric acid. The DPPH·scavenging effect of four substances had different trends in dosage ranges of 0.1mL~0.5mL and 0.5mL~1mL. In 0.1mL~0.5mL dosage range, the DPPH·scavenging effect of the crude extract, the refined extract and ascorbic acid were almost the same, and significantly greater than citric acid. In 0.5mL~1mL dosage range, only the DPPH·scavenging effect of the refined extract close to ascorbic acid. The nitrite scavenging effect of the refined extract and the crude extract in the dosage range of 0.5mL~2mL were stronger than citric acid. Especially, in the dosage of 2mL, the nitrite scavenging effect of the refined extract was 3 times as citric acid. The comparison show that the in vitro antioxidant capacity of the refined extract and the crude extract of total flavonoids in hovenia seeds were strong, and the in vitro antioxidant capacity of the refined extract was stronger than the crude extracts.
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