| Jujube (Zizyphus Mill) which is a traditional Chinese fruit with dual use as food and medicine originates from both sides of Yellow River. It has more than two thousand years of cultural history. Pear-Jujube (Zizyphus jujuba Mill.cv.Lizao) is an important fresh jujube variety which is big, crisp, delicious and rich in vitamins, minerals and phenolic compounds. As a new type of fruit, it is very popular on market. According to the policy of returning farmland to forest in China, jujube is considered an ecological restoration and economically beneficial species that can be cultivated in the region. Probing into the effect of different drip irrigation regimes on edible quality and antioxidant of Loess Plateau pear-jujube, and providing the scientific evidence for high-quality production jujube on the Loess Plateau, the fruits of seven to eight years old dwarfing close planting pear-jujube trees were selected as experimental materials and the fruits of no irrigation jujube-trees were chosen as control group. In this study, we compared the edible quality, the content of total phenolics, total flavonoids, the composition of phenolics and organic acids, and the antioxidant capacity including inhibitory capacity on lipid peroxidation, reducing power, DPPH radical-scavenging capacity and ABTS radical cation decolorization capacity under different drip irrigation regimes. Main conclusions obtained were as follows:(1) Different irrigation regimes had no significant effect on water content, pH, reducing Vc; the titratable acid (TA), total soluble solids (TSS), reducing sugar, total sugar content among pear-jujubes under different irrigation regimes were significantly different; the firmness and resilience of pear-jujube were also affected by different irrigation regimes.(2) Under the drip irrigation regimes designed in our study, different irrigation amount and frequency had no significant effect on total phenolics content. But the content of total flavonoids and the four models of antioxidant capacity all showed significant discrepancies (p<0.05) among different regimes. The antioxidant capacity had significant correlation with total flavonoids content.(3) The HPLC analysis showed that polyphenols in pear-jujube were Protocatechuic acid, catechin, epicatechin and rutin; the organic acids were tartaric acid, malic acid, Vc, citric acid; the content of tartaric acid in Jujube and polyphenols: catechin, epicatechin and rutin had also been significantly affected (p<0.05). |
