This study aimed to use Raman spectroscopy to identify the producing areas of peanut oil and build a robust discriminant model to further screen out the characteristic spectra closely related to the origin.  Raman spectra of 159 peanut oil samples from different provinces and different cities of the same province were collected.  The obtained data were analyzed by stepwise linear discriminant analysis (SLDA), k-nearest neighbor analysis (k-NN), support vector machine (SVM) and multi-way analysis of variance.  The results showed that the overall recognition rate of samples based on full spectra was higher than 90%.  The producing origin, variety and their interaction influenced Raman spectra of peanut oil significantly, and 1 400–1 500 cm^–1 and 1 600–1 700 cm^–1 were selected as the characteristic spectra of origin and less affected by variety.  The best classification model established by SLDA combined with characteristic spectra could rapidly and accurately identify peanut oil’s origin.

Phosphoenolpyruvate carboxylase (PEPC; EC 4.1.1.31) catalyses phosphoenolpyruvate (PEP) to yield oxaloacetate, which is involved in protein biosynthesis. Pyruvate kinase (PK; EC 2.7.1.40) catalyzes PEP to yield pyruvate, which is involved in fatty acid synthesis. In this study, five PEPC genes (AhPEPC1, AhPEPC2, AhPEPC3, AhPEPC4, and AhPEPC5) from peanut have been cloned. Using a quantitative real-time RT-PCR approach, the expression pattern of each gene was monitored during the seed development of four peanut varieties (E11, Hebeigaoyou, Naihan 1, and Huayu 26). It was found that these five genes shared similar expression behaviors over the developmental stages of E11 with high expression levels at 30 and 40 d after pegging (DAP); whereas these five genes showed irregular expression patterns during the seed development of Hebeigaoyou. In Naihan 1 and Huayu 26, the expression levels of the five genes remained relatively high in the first stage. The PEPC activity was monitored during the seed development of four peanut varieties and seed oil content was also characterized during whole period of seed development. The PEPC activity followed the oil accumulation pattern during the early stages of development but they showed a significantly negative correlation thereafter. These results suggested that PEPC may play an important role in lipid accumulation during the seed development of four peanut varieties tested.