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This study investigates the chemical composition and bioactive components of three natural Cordyceps sinensis and one culture mycelium, and further compares the antioxidant properties of their aqueous extracts. The contents of crude fat and total amino acids were significantly higher in cultured sample. Glutamic acid was the most abundant amino acid in all samples; arginine was the second major amino acid in natural samples, while in cultured sample it contained large quantity of aspartic acid and leucine. The contents of minerals, except for Cr, Mo, Sn, V and Cd, were significantly different between natural and cultured samples. The content of mannitol in natural samples was significantly higher, ranging from 9.85% to 11.51%, while in the mycelium the value was less than half. On the contrary, the levels of polysaccharide, adenine and adenosine in cultured sample amounted to 10.43%, 0.50 mg/g and 2.61 mg/g, respectively, considerably higher than the natural ones. There was no difference in content of guanosine among four samples. Cordycepin was not detected in the four samples examined. Additionally, in vitro antioxidant activity evaluations showed that water extracts of cultured sample had a stronger ability in scavenging DPPH and hydroxyl radicals, as well as a higher reducing power. [ABSTRACT FROM AUTHOR]

Furan, a possible carcinogen, is commonly produced by thermal processing in a number of heated foods. In this study, the effects of several natural and synthetic antioxidants on thermally induced furan formation in ascorbic acid, linoleic and linolenic acid model systems were investigated, and results demonstrated that not all of the antioxidants tested showed mitigating effects on furan formation. For the ascorbic acid model system, chlorogenic acid was found to be the most efficient antioxidant in suppressing furan formation. For the linoleic and linolenic acid model systems, the most significant reduction (92% in the former and 80% in the latter) was observed in the case of model systems with butylated hydroxytoluene. In addition, the effects of antioxidants on the kinetics of furan formation were investigated by adding chlorogenic acid into the ascorbic acid model system and sesamol into both linoleic and linolenic acid model system, and the results showed that the mitigating effects of antioxidants might decline with increasing heating time. To describe the kinetics of furan formation from these model systems, power function models were established by non-linear regression and the results indicated that the proposed models could successfully fit the experimental data (R 2 > 0.988). [ABSTRACT FROM AUTHOR]

In this study, the levels of furan and 2-alkylfurans (2-methylfuran, 2-ethylfuran, 2, 5-dimethylfuran, 2-propylfuran, 2-butylfuran, 2-pentylfuran) were determined in a variety of foodstuffs by static headspace gas chromatography and mass spectrometry. The headspace operating conditions and the effects of food matrix on the responses of analytes were investigated. Besides, the co-elution of 2-ethylfuran/2, 5-dimethylfuran was processed using the automated deconvolution software for the correct identification and quantification of 2-ethylfuran and 2,5-dimethylfuran in food samples. The external matrix matched standard calibration method was chosen to correct the matrix effects for the analysis of furan and 2-alkylfurans in a total of 126 food samples. Results showed that furan and 2-alkylfurans were detected in 70.6% of food samples with total concentrations ranging from 0.5 to 789.4 ng g −1 . [ABSTRACT FROM AUTHOR]

3-chloropropane-1, 2-diol (3-MCPD) esters are a kind of food processing contaminants that especially occur in edible oil. This study investigated the impact of various factors on the formation of 3-MCPD esters in edible oil models with sodium chloride as chlorine donator during heat processing. The amount of 3-MCPD esters generated in the models were positively correlated with the concentration of sodium chloride. Fe 3+ could significantly promote the formation of 3-MCPD esters. The formation of 3-MCPD esters also depended on pH value of oil, heating temperature and time. The highest level of 3-MCPD esters were obtained at pH 4.0 (2925.3 μg/kg), at 220 °C (9509.8 μg/kg) and for 8 h (4852.4 μg/kg), respectively. 3-MCPD esters were generated much more in the continuous heating model than in the intermittent one. The results are valuable to better understand the formation of 3-MCPD esters and also can provide references for reduction of 3-MCPD esters during edible oil processing and household cooking. [ABSTRACT FROM AUTHOR]

[Display omitted] • A HPLC method for detecting 15 carbonyls in frying oils has been developed. • Lower linolenic acids were found in frying oils of rice cakes and hairtails. • Fewer and lower carbonyls were detected in frying oils of rice cakes and hairtails. • Results of POV and pAV were in agreement with those of carbonyls in frying oils. This study investigated the effects of frying of foods on the fatty acids and formation of carbonyl compounds in frying soybean oils. Rice cakes and hairtails were selected as typical starch/protein-based foods for frying using soybean oil. In this study, fifteen carbonyl compounds were detected by an efficient high performance liquid chromatography (HPLC) developed by this paper. During frying with rice cakes or hairtails, the linolenic acid in frying oils was reduced by approximately 20 % compared with that in the no-food frying system. Fewer types of carbonyl compounds (frying without food: 11; frying of rice cakes: 9; frying of hairtails: 6) were detected, and the levels of some carbonyl compounds such as trans-2-nonenal were decreased. Results suggested that frying rice cakes or hairtails can substantially influence the contents of fatty acids and the formation of carbonyl compounds in frying oils. This study provides references for evaluating the quality of fried oil and food. [ABSTRACT FROM AUTHOR]