Effect of cooking methods on nutritional quality and volatile compounds of Chinese chestnut (Castanea mollissima Blume).

This study aimed to evaluate the effects of different cooking methods on the content of important nutrients and volatiles in the fruit of Chinese chestnut. The nutritional compounds, including starch, water-soluble protein, free amino acids, reducing sugar, sucrose, organic acids and total flavonoids, of boiled, roasted and fried chestnuts were significantly (P<0.05) lower than those of fresh chestnuts after cooking, while the amylose, fat, crude protein and total polyphenol content varied slightly (P>0.05). L-Aspartic acid, L-glutamic acid and L-arginine were found to be the main reduced free amino acids in cooked chestnuts. The main aromatic compositions in fresh chestnuts were aldehydes and esters, while ketones, furfural and furan were formed in cooked chestnuts due to the Maillard reaction and degradation of saccharides, amino acids and lipids. Principle component analysis demonstrated that roasting and frying had a similar effect on the nutritional composition of chestnuts, which differed from that of the boiling process.

Rapid detection of authenticity and adulteration of walnut oil by FTIR and fluorescence spectroscopy: a comparative study.

Fourier transform infrared (FTIR) and fluorescence spectroscopy combined with soft independent modeling of class analogies (SIMCA) and partial least square (PLS) were used to detect the authenticity of walnut oil and adulteration amount of soybean oil in walnut oil. A SIMCA model of FTIR spectra could differentiate walnut oil and other oils into separate categories; the classification limit of soybean oil in walnut oil was 10%. Fluorescence spectroscopy could differentiate oil composition by the peak position and intensity of emission spectrum without multivariate analysis. The classification limit of soybean oil adulterated in walnut oil by fluorescence spectroscopy was below 5%. The deviation of the prediction model for fluorescence spectra was lower than that for FTIR spectra. Fluorescence spectroscopy was more applicable than FTIR in the adulteration detection of walnut oil, both from the determination limit and prediction deviation.