Abstract:For problems of food safety caused by microbial contamination and environmental safety due to drug-resistant strains, the development of emerging natural food additives with broad-spectrum and high-efficiency has been vital study trends in a modern food safety. Antimicrobial peptides(AMPs) are paid much attention for its advantage of broad-spectrum, good stability, unique antimicrobial mechanism of action and lower residue. With the further research, AMPs are expected to play a vital role in the application of food safety. Considering it, AMPs-related researches abroad were concluded in recent years. A review of the exploring and classification situation of AMPs,the development of bio-resistance and mechanism for bacteria, fungi, parasites, virus and tumor cells was provided. Meanwhile, the potential application fields of AMPs in food safety and scientific problems urgent to solve were analyzed. The resolution strategy also is provided for researchers as a reference in the field.

Abstract:China is the country with the largest planting area and yield of watermelon in the world.In 2014, planting area and yield of watermelon was 1.852×10⁶hm² and 7.4843×10⁷t, accounting for 53.3% and 67.4% of the data around the world. The harvest period of watermelon is short, mainly between June to August. In order to avoid wasting, the watermelon deep processing products are developed, and watermelon juice is one of the most suitable one.Because of the presence of sensitive components, nutrients and flavor of watermelon juice were impacted greatly during processing. In this paper, aroma formation pathway of watermelon juice, key aroma compounds, and the effects of different processing methods (thermal and non-thermal processing) on the nutrition, sensory quality and flavor of watermelon juice were reviewed. The research direction was proposed about how to maintain the quality and flavor of watermelon juice during processing in the future.

Abstract:Fresh-cut vegetables have obtained more and more attentions due to the qualities of freshness, nutrition, and convenience. Development of fresh cut vegetables in China is later than developed countries. Fresh cut vegetables' industries were concentrated in the aera of raw materials production, key sales area, and the aera with convenient transportation while there is less in other small cities. Therefore, it has a huge market space. However, cutting processing led to cellular damage in tissues which caused microbial growth and a series of complex physiological and biochemical reactions, thus seriously affecting the shelf life of fresh-cut vegetables. Discussed with the aspects of treatment methods, processing equipment and key technologies of fresh cut vegetables in China and abroad, the effects of main processing procedures of fresh cut vegetables, such as segmentation, cleaning, dehydration, and packaging technology on quality were reviewed in this paper. Furthermore, the main developing direction was put forward which will provide theoretical and technical supports for fresh-cut vegetables industry.

Abstract:Materials of low-glycemic-index mixing powder were screened, on this basis, the formula of low-glycemic-index mixing powder was designed. Then, the effects of different processing methods (steaming, extruding and roller-drying) on expected glycemic index (eGI) and the solubility index (drying-matter solubility index, DSI) were investigated and the optimal processing method and parameters were obtained. Finally, the in vivo glycemic response to mixing powder was measured. The results showed that after cooking, extrusion, or roller-drying, oats, chickpeas, and bean had lower eGI. The optimal ratio of oat∶ chickpea∶ colored kidney bean was 16.43∶76.35∶7.22 in the mixing powder. The mixing powder with high DSI (16.45%) and low eGI (57.41) was achieved using extruding with terminal barrel temperature procedure of 60℃-80℃-100℃-120℃, water content of 25%, and screw speed of 100r/min. When glucose was regarded as 100, the glycemic index (GI) of mixing power was 52.13, suggesting the mixing powder belonged to low-GI foods.

Abstract:Soybean dregs contain rich nutrients and have a lot of bioactivities. The dietary fiber in bean dregs can prevent diabetes, bowel cancer, cardiovascular diseases, obesity, and increase defecation. Soybean dregs, mixed with wheat flour and corn flour, could be used as materials in baked food. The extrusion technology was applied to increase the quality of soybean dregs and the expansion degree and soluble dietary fiber content were investigated. The results showed that under the condition of the rotate speed of 360 r/min, extruded material water content of 21% and 170℃, the puffed material was loose and porous, and had the good expansion degree, which could be used as raw material for baking food.

Abstract:In this study, Lactobacillus plantarum R23 was used as the tested bacteria, and the effects of collecting conditions, pre-freezing conditions and freeze-drying time on cell viability were studied by scanning electron microscope,transmission electron microscope,and the orthogonal test. The results showed that the amount of bacteria reached the maximum and higher activity at the 15th hour during the process of incubation, which might be considered as the suitable harvest time. The cell survival could reach 92.4% under optimum conditions, of which the centrifugal force played a key role. The optimum temperature and duration of gradient pre-freezing were -20, -40, -80℃ and 1,2, 3h, respectively. And the optimum moisture content of Lactobacillus plantarum R23 to be storaged was 1.20%. Based on this study, the interference mechanism of the key factors for DVS preparation on cells was explicited, and the suitable preparation conditions were obtained, which was a guidance to the large scale production of high efficient DVS.

Abstract:To determine flavonoid compounds of quercetin-7-glucoside and apigenin in sorghum pigment, the method of HPLC-double wavelength was established. Two components were extracted and disolved after pretreatment and determined by the retention time and UV absorption spectra. Then they were analyzed by HPLC on a C₁₈ column and detected at the wavelength of 486nm and 333nm for quercetin-7-glucoside and apigenin respectively, with a mobile phase of methanol and 1% acetic acid for gradient elution. The velocity of flow was 1.0mL/min and the injection volume was 20μL. The components were quantitatively determined by calculating the peak areas. The results showed that the calibration curve was liner in the range of 10.2-408.0μg/mL with the correlation coefficients of more than 0.999. The detection limit was 2μg/mg. The average recoveries ranged from 97.3% to 102.8%, and the relative standard deviations (RSD) were 1.6%-3.9% (n=6). The method showed good repeatability, accuracy, and stability and could be applied in the accurate quantification of two flavonoid components in sorghum pigment.

Abstract:cAMP(cyclic adenosine 3′,5′-monophosphate) and cGMP(cyclic guanosine 3′,5′-monophosphate) are ubiquitous second messengers which regulate myriads of functions in eukaryotic cells, and their signaling pathways are regarded as the popular target in functional food bioactives screening. In this review, we discuss the advantages and disadvantages of techniques such as radioisotope, homogeneous non-radioactive isotope and heterogeneous non-isotopic methods, which are used to measure cAMP and cGMP and describe how these techniques can be applied. The homogeneous non-radioactive isotope methods, including fluorescence resonance energy transfer technology (FRET), homogeneous time-resolved fluorescence resonance energy transfer technology (TR-FRET), polarization fluorescence detection technology (FP), are suitable for cAMP/cGMP high-throughput screening of bioactives for functional food based on its advantages of easy operation, high specificity and sensitivity.

Abstract:The major factors affected the stability of whole grain milk was investigated. Then the emulsion stabilizer was screened and its proportion was optimized. Moreover, the effects of sucrose and sodium tripolyphosphate on the stability of the system were discussed. The results showed that the best ratio of sucrose fatty acid ester and distillation monostearin was 2∶8, and the dosage of mixed emulsifier was 0.20%. The optimum concentration of the best stabilizer was 0.05% xanthan gum, 0.15% carboxymethyl cellulose, and 0.08% microcrystalline cellulose. The stability of the system could be improved by adding sucrose and sodium tripolyphosphate. However, when the sucrose content reached 4%, the centrifugal suspension ratio decreased gradually.

Abstract:This study investigated that the wild kiwi milk tablets were produced by mixing, drying, granulating, and tabletting using wild kiwi fruit juice as the main raw material. The L₉(3³) orthogonal test was carried out with the quality ratio of wild kiwi fruit and milk powder, soluble starch and isomaltooligosaccharide as the factors. The optimal product index was selected with the sensory standard as the scoring index. The best formula was as follows:the mass ratio of wild kiwi fruit and milk powder 4∶1, the amount of soluble starch 15%, and the amount of isomaltooligosaccharide 15%. Meanwhile, 70% ethanol solution was used as the wetting agent, and 0.5% magnesium stearate was used as the lubricant. The wet granulation drying temperature was 50℃. The produced milk tablet has a smooth surface and flavor of kiwi fruit and milk.

Abstract:To explore the effects of different intercropping patterns on tea-planted soils and tea nutritional qualities, both the main chemical characters of soils and nutritional components in fresh tea leaves were detected, which were sampled from the fruit-tea intercropping and pure tea gardens in the east Dongting (ED) and west Dongting (WD) mountain. The results showed that the fruit-tea intercrop effectively relieved soil acidification and improved the nutritive and mineral contents of the topsoil (0-25cm). The principal component analysis showed that the nutrient composition, mineral contents, and acid alkali of soil were the main factors that influenced the properties of tea-planted soil. It was found that the best soil nutrient status appeared in the loquat-tea intercropping plantation in WD, decreasingly followed by the pure tea plantation in WD, waxberry-tea intercrop in ED, the pure tea plantation in ED, and the loquat-tea intercrop in ED. Effects of fruit-tea intercropping patterns and tea-producing districts on nutritional qualities of fresh-leaves were different. In ED, the contents of free amino acids and tea polyphenols in fruit-tea intercropping plantations were slightly higher than those of pure tea plantation, while contents of catechin and caffeine were lower than those of pure tea plantation. In WD, the contents of tea polyphenol, catechin, and caffeine in fresh tea leaves from the waxberry-fruit intercropping plantation were lower than those of pure tea plantation. Moreover, the results indicated that the free amino acid content was negatively related to the contents of Fe and Zn in soil, and tea polyphenol was positively related to the alkaine nitrogen, organic matter, and Zn. Meanwhile, caffeine was positively related to electric conducti-vity, total nitrogen, effective phosphorus, alkaline nitrogen, Ca and Fe, but it was negatively related to the total potassium. Above all, it was clear that fruit-tea intercrop played significant roles in soil environment, and the study provided important evidences for quality improvement and production management of the Dongting Biluochun tea.

Abstract:In this study, a method of simultaneous determination of 19 kinds of polychlorinated biphenyls in aquatic products by gas chromatography-quadrupole time-of-flight mass spectroscopy was established. The samples were extracted by the use of dispersed high-speed homogenization technique with mixed solution of acetone and petroleum ether as extraction solvent, the extracting solution doubly purified by concentrated sulfuric acid and chromatographic column, eluted by n-hexane. The extracting solution was separated by GC capillary column(HP-5MS) with helium as a carrier gas at the flow rate of 1.5mL/min. The resultant separation was ionized by electron impact ion source. The data were collected by TOF/MS full scan mode. The qualitative analysis was performed using retention time and ion precise mass number, and the quantitative analysis was performed using the external standard method. The results showed that the calibration curves of 19 kinds of PCBs showed good linearities when the concentrations from 5.0μg/L to 500.0μg/L, and the correlation coefficients of more than 0.9986, the limits of detection (LOD, S/N=3) between 0.12μg/kg and 1.07μg/kg and the limits of quantification(LOQ, S/N=10) between 0.40μg/kg and 3.57μg/kg. At 3 different standard addition levels of 5.0,0.0, and 20.0μg/kg, the average recoveries of 19 kinds of PCBs was between 79.6% and 103.4%, and the intra-day relative standard deviation was between 2.2%~9.6%. While at 3 different standard addition levels of 20.0,0.0, and 200.0μg/kg, the average recoveries of 19 kinds of PCBs was between 77.4% and 104.6% and the inter-day relative standard deviation was between 2.7% and 9.8%. It is indicated that, the developed method is accurate, sensitive and reliable and suitable for the monitoring and detection of 19 kinds of PCBs in aquatic products.

Abstract:Food safety is a global problem and developing countries are more troubled. In China, food safety incidents have often occurred in recent years. It is an important research method to study the demand characteristics of food safety from the perspective of consumers. Based on the questionnaire for consumers in the form of analysis the characteristic of food safety requirements and consumer's willingness to pay (WTP) for high security and high prices milk to be explained variable to do modeling analysis, the key factors that affect consumer food safety requirements were concluded. The results could avoid the waste of resources and solve the problem of unbalanced supply and demand. On another hand, the results could meet the different needs of consumers. Results indicate that the monthly house, hold spending, whether imported milk on behalf of food safety, age, occupation and so on four factors have significant impacts. Monthly household spending, age, and occupation have positive effects while whether imported milk on behalf of food safety has negative effect.