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Gas chromatography-mass spectrometry (GC-MS) and electronic tongue were used to quantitatively determine the volatile compounds and taste indices of 21 Jiang-flavor baijiu samples of different grades. These samples were differentiated by chemometrics, and key differential compounds among grades were identified. Finally, a discriminant model was established by machine learning. The results showed that there were differences in the contents of volatile compounds in Jiang-flavor baijiu of three grades, indicating the feasibility of further discriminant analysis. The total content of flavor compounds in second-grade baijiu (4 908 mg/L) was significantly lower than that in premium-grade (6 583 mg/L) and first-grade baijiu (8 254 mg/L), while the proportion of several esters responsible for floral and fruity aromas in total esters showed a decreasing trend as the grade decreased. Partial least squares-discriminant analysis (PLS-DA) identified 16 key differential compounds represented by ethyl palmitate and acetic acid. The results of electronic tongue showed that the taste indexes of premium-grade baijiu were more consistent, with lower bitterness and astringency aftertaste. The taste indexes of second-grade baijiu showed significant intersample differences. Principal component analysis (PCA) showed clear discrimination of Jiang-flavor baijiu of different grades according to their taste indexes. The above results provide a basis for the establishment of Jiang-flavor baijiu quality system. Four discriminant models were established based on 25 differential compounds and taste indexes identified. The accuracy of all models was higher than 90%, and the support vector machine (SVM) model performed best, with an accuracy of 100%.

The ameliorative effect of chitooligosaccharides (COS) on hydrogen peroxide (H2O2)-induced injury in hepatic cells was evaluated. An oxidative stress injury model was established by stimulating L-02 cells with H2O2, and the level of reactive oxygen species (ROS), mitochondrial membrane potential and related genes (IL-6 and TNF-α) were analyzed. The results showed that COS could improve the proliferation activity, and suppress the decrease in mitochondrial membrane potential and the increase in ROS level in H2O2-injured L-02 cells (P < 0.05). Single cell nano biochemical analysis showed that COS treatment balanced the fluctuation of ROS level in the cells. In addition, COS improved the transcription levels of genes related to inflammation (IL-6 and TNF-α), apoptosis (Caspase 3, Caspase 9, Bax and Bcl-2) and oxidative stress (Nrf2 and HO-1), thereby antagonizing apoptosis and oxidative stress. Conclusively, COS possess protective effects on H2O2-induced injury in L-02 cells, which lays a theoretical foundation for the application and development of COS.

In this work, black sesame melanin was used as template and reducing agent to prepare a melanin-nanoselenium complex. The preparation process was optimized, and its structure and morphology were characterized. Also, its antioxidant capacity in vitro was tested, and its protective effect on oxidative damage of red blood cells and EAhy926 endothelial cells was evaluated. Its anticancer activity and biocompatibility were investigated by using lung cancer cell line A549 and shrimp killing experiment. The results showed that the optimum conditions for the synthesis of melanin-nanoselenium complex were as follows: volume ratio of melanin solution (0.3 mg/mL) to selenium dioxide solution (0.555 mg/mL) 9:5, pH 7, and reaction time 5 h with magnetic stirring (400 r/min). The results of X-ray photoelectron spectroscopy (XPS) showed that Se4+ was completely reduced. The results of infrared (IR) spectroscopy indicated that the carboxyl and conjugate structures of melanin might be involved in the reaction. According to the results of characterization by synchronous light scattering, the particle size of the melanin-nanoselenium complex was approximately 200 nm, and it was stable and could be well distributed in water dispersion system. The complex remained stable for 2 h in simulated gastric juice, and was pH tolerant. It could be released slowly in simulated intestinal juice, thus having the potential for long-term sustained release. In vitro antioxidant results showed that the scavenging capacity against 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation and total reducing power of the complex were significantly better than those of selenium dioxide. The complex significantly inhibited hemolysis of red blood cells and oxidative damage of EAhy926 endothelial cells induced by hydrogen peroxide, and had inhibitory activity on lung cancer cells. The toxicity of this complex was weaker than that of selenium dioxide, whose semi-lethal concentration (LC50) values were 347.393 and 19.781 µg/mL, respectively. This study is meaningful for guiding further research on melanin resources and the preparation of melanin-nanoselenium complex, and also provides a theoretical basis for the use of melanin-nanoselenium complex as a dietary selenium supplement.

为了延长煎炸油的使用寿命，有效降低成本，研究了荤素分类煎炸对油脂品质的影响。采用食材荤素分类及不分类煎炸并循环使用煎炸油，分析了两种煎炸方式下煎炸油的色泽、酸值、过氧化值、p-茴香胺值、极性组分含量的变化情况，并对比分析两种煎炸方式用油量。结果表明：采用荤素分类煎炸可以更好地抑制油脂色泽、酸值、p-茴香胺值及极性组分含量的增长速度；不分类煎炸油脂的色泽在煎炸2 d后无法用比色仪检测，分类煎炸7 d后油脂的色泽才接近不分类煎炸2 d的色泽；不分类煎炸的油脂酸值(KOH)在煎炸前3 d内急剧上升，由初始的0.09 mg/g增至1.30 mg/g，分类煎炸的油脂酸值(KOH)浮动较小，由初始的0.09 mg/g最高增加至0.62 mg/g；在煎炸7 d 时，不分类煎炸的油脂p-茴香胺值由初始的4.0增加到38.0，分类煎炸的油脂p-茴香胺值由初始的4.0增加到15.0，不分类煎炸油脂的p-茴香胺值的增长速度是分类煎炸的近3倍；不分类煎炸，油脂极性组分含量在第1天内急剧上升，在第4天达到最高，为12.5%，后逐渐趋于平稳，分类煎炸，油脂极性组分含量在前3 d内均保持在8%左右，之后才有上升的趋势，最终维持在9%左右；相比不分类煎炸，分类煎炸可节约25%的用油量。综上，荤素分类煎炸可以改善煎炸油品质，延长其使用寿命，提高利用率。 In order to prolong the service life of frying oil and reduce cost effectively, the effect of classified frying of meat and vegetable on the quality of oil was studied. The color, acid value, peroxide value, p-anisidine value and polar components content of frying oil were analyzed under two frying methods by using classified and non classified frying of meat and vegetable and recycling frying oil, and the oil consumption of the two frying methods was compared. The results showed that the classified frying of meat and vegetable could better inhibit the growth rate of oil color, acid value, p-anisidine value and polar components content. The color of non classified frying oil could not be detected by colorimeter after 2 d of frying, and the color of classified frying oil after 7 d of frying was close to the color of non classified frying oil for 2 d. The acid value of non classified frying oil increased sharply in the first three days of frying, from the initial 0.09 mgKOH/g to 1.30 mgKOH/g, and the acid value of classified frying oil fluctuated slightly, from the initial 0.09 mgKOH/g to 0.62 mgKOH/g at the highest. After 7 d of frying, the p-anisidine value of non classified frying oil increased from 4.0 to 380, and the p-anisidine value of classified frying oil increased from 4.0 to 15.0. The growth rate of the p-anisidine value of non classified frying oil was nearly three times that of classified frying oil. The polar components content of non classified frying oil increased sharply in the first day, the maximum was 12.5% on the fourth day, and then gradually stabilized. The polar components content of classified frying oil remained at about 8% in the first three days, then increased, and finally remained at about 9%. Classified frying could save 25% oil consumption compared with non classified frying. Classified frying of meat and vegetable can improve the quality, service life and utilization rate of frying oil.