Abstract:In this paper, the biosynthesis process of phenolic compounds in plants is summarized, which includes the shikimate, pentose phosphate and phenylpropanoid pathways. Plant phenolic compounds can act as antioxidants, structural polymers (lignin), attractants (flavonoids and carotenoids), UV screens (flavonoids), signal compounds (salicylic acid and flavonoids) and defense response chemicals (tannins and phytoalexins). From a human physiological standpoint, phenolic compounds are vital in defense responses, such as anti-aging, anti-inflammatory, antioxidant and anti-proliferative activities. Therefore, it is beneficial to eat such plant foods that have a high antioxidant compound content, which will cut down the incidence of certain chronic diseases, for instance diabetes, cancers and cardiovascular diseases, through the management of oxidative stress. Furthermore, berries and other fruits with low-amylase and high-glucosidase inhibitory activities could be regarded as candidate food items in the control of the early stages of hyperglycemia associated with type 2 diabetes.

No abstract

Nowadays, pesticides are widely used in preventing and controlling the diseases and pests of crop, but at the same time pesticide residues have brought serious harm to human’s health and the environment. It is an important subject to study microbial degradation of pesticides in soil environment in the field of internationally environmental restoration science and technology. This paper summarized the microbial species in the environment, the study of herbicide and pesticides degrading bacteria and the mechanism and application of pesticide microbial degrading bacteria. Cypermethrin and other pyrethroid pesticides were used widely currently, while they were difficult to be degraded in the natural conditions, and an intermediate metabolite, 3-phenoxy benzoic acid would be produced in the degradation process, causing the secondary pollution of agricultural products and a series of problems. Taking it above as an example, the paper paid attention to the degradation process of microorganism under natural conditions and factors affecting the microbial degradation of pesticide. In addition, the developed trend of the research on microbial degradation of pesticide and some obvious problems that need further solution were put forward.

Ternary blend films were prepared with different ratios of starch/polyvinyl alcohol (PVA)/citric acid. The films were characterized by field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis, as well as Fourier transform infrared (FTIR) analysis. The influence of different ratios of starch/polyvinyl alcohol (PVA)/citric acid and different drying times on the performance properties, transparency, tensile strength (TS), water vapor permeability (WVP), water solubility (WS), color difference (∆E), and antimicrobial activity of the ternary blends films were investigated. The starch/polyvinyl alcohol/citric acid (S/P/C 1:1:0 , S/P/C 3:1:0.08 , and S/P/C 3:3:0.08 ) films were all highly transparent. The S/P/C 3:3:0.08 had a 54.31 times water-holding capacity of its own weight and its mechanical tensile strength was 46.45 MPa. In addition, its surface had good uniformity and compactness. The S/P/C 3:1:0.08 and S/P/C 3:3:0.08 showed strong antimicrobial activity to Listeria monocytogenes and Escherichia coli, which were the food-borne pathogenic bacteria used. The freshness test results of fresh figs showed that all of the blends prevented the formation of condensed water on the surface of the film, and the S/P/C 3:1:0.08 and S/P/C 3:3:0.08 prevented the deterioration of figs during storage. The films can be used as an active food packaging system due to their strong antibacterial effect.

Volatile aldehydes (VAs) formed during soybean oil (SBO) heating, wheat dough (WD) frying, and chicken breast meat (CBM) frying processes were comparatively investigated by solid-phase micro-extraction-gas chromatography-mass spectrometry (SPME-GC-MS). The results showed that relative amounts (RAs) of the most detected VAs were firstly increased to maximum values in oil samples collected at the second hour of the seventh day and the values were then decreased with the increase in the time of oil heating process (control). However, for food frying processes, the time needed for reaching maximum RAs of VAs was shorter and the values were decreased with the increase in frying time. Significant change in contents of the VAs was observed for oil samples fried with CBM due to the high contents of water, protein, and lipid content compared to oil samples fried with WD. Based on the obtained results, free radical reaction, particularly positional isomerization and cis-trans isomerization, was deduced to occur when WD or CBM was fried in SBO. The relatively high RAs of VAs formed during the deep-fat frying process presented certain invaluable measures for evaluating of frying oil and fried food quality and safety.

In order to explore snow chrysanthemum polysaccharides (SCPs) as functional food ingredients and natural antioxidants for industrial applications, both microwave-assisted extraction (MAE) and ultrasonic-assisted extraction (UAE) were firstly optimized for the extraction of SCPs. Furthermore, the effects of conventional hot water extraction, UAE, and MAE on the chemical structures and antioxidant activities of SCPs were investigated. The maximum extraction yields of SCPs extracted by UAE (4.13 ± 0.24%) and MAE (4.26 ± 0.21%) were achieved at the optimized extraction parameters as follows: ultrasound amplitude (68%) and microwave power (500 W), ultrasound extraction time (21 min) and microwave extraction time (6.5 min), and ratio of liquid to raw material (42.0 mL/g for UAE and 59.0 mL/g for MAE). In addition, different extraction methods significantly affected the contents of uronic acids, the molecular weights, the molar ratio of constituent monosaccharides, and the degree of esterification of SCPs. SCPs exhibited remarkable DPPH (IC50 ≤ 1.702 mg/mL), ABTS (IC50 ≤ 1.121 mg/mL), and nitric oxide (IC50 ≤ 0.277 mg/mL) radical scavenging activities, as well as reducing power (≥ 80.17 ± 4.8 μg Trolox/mg), which suggested that SCPs might be one of the major contributors toward the antioxidant activities of snow chrysanthemum tea. The high antioxidant activities (DPPH, IC50 = 0.693 mg/mL; ABTS, IC50 = 0.299 mg/mL; nitric oxide, IC50 = 0.105 mg/mL; and reducing power, 127.79 ± 2.57 μg Trolox/mg) observed in SCP-M extracted by the MAE method might be partially attributed to its low molecular weight and high content of unmethylated galacturonic acids. Results suggested that the MAE method could be an efficient technique for the extraction of SCPs with high antioxidant activity, and SCPs could be further explored as natural antioxidants for industrial application.

No abstract

A rapid and reliable approach based on SERS for quantitatively detecting RB in chili powder using a paper-based substrate was developed.