| Recently, many epidemiological studies suggest that there was a correspondence between the consumption of fruits and vegetables and the prevention of the diseases and aging. This was attributed to antioxidants from vegetables and fruits. Chinese hickory (Carya cathayensis Sarg.), a perennial woody plants, is primarily natives of China. The nut from Carya genus are founded to possess high antioxidant activities. In the current study, antioxidant activities in vitro of Chinese hickory and the influence factors on the variation of them were evaluated, and involved antioxidant compounents were identified and measured.Tthe research of isolated protein from Chinese hickory and the cloning of LOX gene was also carried out in this paper.In this study, the antioxidant activity of methanol extracts from four species of the Carya genus (C dabieshanensis, C. cathayensis, C. hunanensis, C. illinoensis) was compared by various antioxidant assays, including the reducing power, DPPH radical scavenging activity and the superoxide anion scavenging activity. Total phenolic (TP) and condensed tannins (CT) were determined in all samples spectrophotometrically. At last, individual phenolic compounds were identified and quantified by HPLC methods. Among the four species, C. dabieshanensis and C. cathayensis possess the higher antioxidant activity and nutritional value and more health benefits than C. hunanensis and C. illinoensis. In addition, strong correlations of total phenolic content and condensed tannins content with reducing power, DPPH radical scavenging activities and superoxide anion scavenging activity was also found in this work. This showed that the main components contributions to the overall antioxidant capacity are phenolic compounds. Gallic acid(6690μg/g defatted kernel), catechin(2880μg/g defatted kernel) and ellagic acid(2738.5μg/g defatted kernel) were the main phenolic compounds identified by HPLC in Chinese hickory.The effect of thermal process(boiling, pressured-steam heating, microwave baking, roasting) on the phenolic compounds, condensed tannin and antioxidant activities of methanol extracts of chinese hickory kernels was investigated in this work. Several methods for determining antioxidant activities of the samples were employed, including the reducing power, DPPH radical scavenging activity and the superoxide anion scavenging activity. Total phenolic (TP) and condensed tannins (CT) were determined in all samples spectrophotometrically. Comparing with the raw materials, total phenolic content was reduced by 4.47%,7.37%,47.90% and 66.73% and CT reduced by 33.65%,4.79%,46.23% and 69.94% after roasting, microwave baking, boiling, and pressured-steam heating treatment, respectively. In this research, antioxidant activities of Chinese hickory were obviously decreased after boiling and pressured-steam heating, while little influence after roasting and microwaving. A strong correlations between TP and reducing power, DPPH radical scavenging activities and superoxide anion scavenging activity (R2=0.9875, R2=0.9933, R2=0.8917, respectively) was observed. The reduction of phenolic compounds after boiling and pressured-steam heating processing is mainly due to the fact that those compounds consequently leach into the liquid medium. The results of this work indicated Chinese hickory after roasting and microwave baking possessing higher functional benefit than other thermal process to the view of nutritional.The effect of storage conditions on the phenolic compounds, antioxidant activities of methanol extracts of Chinese hickory kernels and oil quality was investigated in this work. Several methods for determining antioxidant activities of the samples were employed, including the reducing power and DPPH radical scavenging activity. Total phenolic (TP) were determined in all samples spectrophotometrically. The oil quality were determined according to GB/T 5009.37-2003 and GB/T 5532-1995. The oxidative rancidity of the oil from Chinese hickory storing at room temperature even flushed with nitrogen is faster than at low temperature. At low temperature, the oxidative rancidity of unshelled chinese hickory is faster than inshelled samples. The total phenolic content of Chinese hickory is increased while the antioxidant activities decreased. This maybe interpreted than the composition of the phenolic compound is changed after storge.Chinese hickory (Carya cathayensis Sarg.) kernel protein was isolated from Chinese hickory kernel defatted flour by isoelectric precipitation. isolated protein was evaluated for chemical composition and selected functional properties including nitrogen solubility index, emulsifying capacity, emulsifying stability, foaming capacity, foaming stability, the least gelation concentration, the water absorption capacity and oil absorption capacity. The isolated protein contained over 72.0% dry weight (DW) of protein. Nitrogen solubility curves for isolated protein were pH-dependent in the pH range of 2.0-12.0 with minimum solubility observed at pH 4.0 (9.8%) and maximum solubility at pH 12.0 (89.9%). Minimum emulsifying capacity, emulsifying stability, foaming capacity and maximum foaming stability of isolated protein were also observed at pH 4.0. Isolated protein had a least gelation concentration of (LGC) of 6% (w/v) at pH 4.0. The water absorption capacity and oil absorption capacity was 1.67±0.06g/g and 1.89±0.02g/g, respectively.The phenolic content, antioxidant activities of the leaves and husks of Chinese hickory was investigated in this work. Several methods for determining antioxidant activities of the samples were employed, including the reducing power and DPPH radical scavenging activity. Total phenolic (TP) were determined in all samples spectrophotometrically. The effect of different solvent on antioxidant activities and total phenolic content and antioxidant activities of extracts of Chinese hickory leaves and husks were investigated in this work. Several methods for determining antioxidant activities of the samples were employed, including DPPH radical scavenging activity, reducing power and superoxide anion scavenging activity. Total phenolic was determined by folin phenol agent. The results showed that all extracts provided various antioxidant activities and methanol and water extracts possessed the highest effect. The optimum concentration of methanol water solution for the extract with highest DPPH elimination was 60%. The highest extraction yield of total phenolic was 10.63±0.31 mg gallic acid equivalents/g of fresh leaves in methanol extract. A correlations between total phenolic content and reducing power, superoxide anion scavenging activity and DPPH radical scavenging activity (r=0.89, p<0.05; r=0.90, p<0.05,r=0.69, p>0.05,respectively) was observed. This may be interpreted that there are some other compounds contributions to DPPH radical scavenging activity. The results show that the capacity of reducing power is in the order of water extracts>VE>80% ethanol extracts> ethyl extracts at the concentration of 1mg/mL. The capacity of scavenging effects on DPPH radicals is in the order of VE>ethyl extracts>water extracts>80% ethanol extracts. The order is VE>water extracts> 80% ethanol extracts>ethyl extracts inβ-carotene linoleate model system. The antioxidant activity of Carya cathayensis green husks may not depend only on the total phenolic compounds content but also on compositions of phenolic compounds.The LOX gene plays an important role in the oxidative rancidity of the oil from chinese hickory. The LOX gene was successfully cloning from the Chinese hickory with 496bp. The LOX gene was also registered at genebank (register number: HM747942). The homology analysis showed that the genome sequences affinity of the LOX gene among Chinese hickory, tomato and rough lemo are high.
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