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In order to investigate the key structural features of peach gum polysaccharide (PGP) responsible for its emulsifying function, partial acid hydrolysis of PGP with 0.1 mol/L trifluoroacetic acid was conducted, yielding hydrolysates 30P, 60P, 120P and 180P with different degrees of hydrolysis at different hydrolysis times. The effects of partial acid hydrolysis on the monosaccharide composition and molecular mass of PGP were analyzed by high performance anion-exchange chromatography (HPAEC) and high performance size-exclusion chromatography with a multi-angle laser light scattering detector (HPSEC-MALLS) and the effect of partial acid hydrolysis on the emulsifying function of PGP was investigated by using an oil in water (O/W) emulsion system. Results showed that PGP was an acidic arabinogalactan composed of arabinose, galactose, xylose, mannose, galacturonic acid and glucuronic acid conjugated with a small amount of protein. PGP, whose average molecular mass of 10 980 kU, presented a flexible coil-like chain in 0.1 mol/L NaNO3 solution. As acid hydrolysis progressed, the contents of uronic acid and protein in PGP gradually increased, the molecular mass and degree of branching gradually decreased, and the molecular conformation of the hydrolysates changed from a flexible coil-like to a rigid rod-like structure. The stability of the O/W emulsion prepared using 60P as an emulsifier was significantly improved compared to the other hydrolysates. It was speculated that 60P, whose molecular mass was 1 188 kU and which had reduced degree of branching and higher contents of glycuronic acid-protein conjugate and exhibited a flexible chain-like structure, may be the key structural feature responsible for of the emulsifying function PGP. This study will be helpful to further explain the mechanism action of PGP as an emulsifier.

For the shortcomings of low operation continuity and low stacking efficiency of the traditional ton-bag loading and unloading methods, a new ton-bag material loading device was designed. Through theoretical calculation, the key body size of the new ton-bag material loading device was determined, and the key components were verified by finite element analysis. By design and calculation, the power required by the screw drive, the moving chain drive and the walking structure of the ton-bag transport device was 99.8,176.4,1 876 W, respectively. The working angle of the telescopic rocker arm structure of forklift stacking device was -43~ 43 °,so that the whole transmission and loading and unloading process is stable, reliable and efficient. This device can better solve the problem of loading of ton-bag materials after packaging, realize seamless docking between vehicle and warehouse, and provide technical and theoretical support for the research and development of food logistics equipment. [ABSTRACT FROM AUTHOR]

Objective: Real-time reverse transcription-polymerase chain reaction(real-time RT-PCR) assay based on Taqman and phylogenetic tree were developed for detecting hepatitis E virus in swine feces of pig farms from several provinces and city., Methods: Designing prime and probe refering to HEV genotype sequences of Genbank, we developed a Taqman-based real-time RT-PCR assay and nested RT-PCR according to HEV conserved domain after optimizing reaction system, then detected the prevalence of HEV infection of pig farms., Results: The sensitivity of the real-time RT-PCR assay established in this experiment was 19. 9 copies/μL, the amplification efficiency was 92. 9%-109. 1%, there was no cross reaction with Sapovirus, Norovirus and Hepatitis A. A total of 342 samples of swine feces were detected. There were two hundred and ten positive samples, and positive rate was 61. 4%. The positive rate of before-fattening was 56. 6%, and after-fattening was 66. 9%. The positive rate of before and after fattening samples had statistical difference(χ~2=24. 8, P<0. 05). The genotype identification system determined that the positive strains isolated in this study were HEV-4 type, and three subtypes of 4 b, 4 d and 4 h were detected., Conclusion: The pig farms of several provinces and city are contaminated by HEV extensively. The genotypes of the isolated strains are all HEV-4 type. The infection rate and infection subtype of pigs in different provinces and cities are different.

Objective: To survey the fungi contamination of four kinds of feed ingredients in 2013- 2014 from parts of China., Methods: A total of 795 feed ingredients including soybean meal, cottonseed meal, wheat bran and distillers dried grains with soluble( DDGS) were collected from representative enterprises in different parts of China. Food safety national standards GB 4789. 15-2010 microbiological examination of food hygiene enumeration of molds and yeast and GB / T 4789. 16-2003 was used to enumerate, isolate and identify fungi, respectively., Results: A total of 25 genus 54species kinds of fungi were isolated and the fungi from Aspergillus, Penicillium, Fusarium were the common contamination fungi in feed ingredients. Wheat bran was the most serious contaminated feed ingredients by fungi, and the detection rate of fungi contamination in four seasons were all greater than 84. 9%, and the exceeding feed limit rate was amount to 20. 8%. The fungi detection rate and contamination level were relatively lower in cottonseed meal and soybean meal, and the exceeding feed limit rate was 0. 9% and 1. 4%, respectively. There were types of feed ingredients, seasonal and regional differences for Aspergillus flavus and Fusarium moniliforme contamination. The detection rate of Aspergillus flavus in wheat bran was higher in four seasons and all surveyed areas, and autumn and winter and huazhong district were with the highest contamination level. The detection rate of Fusarium moniliforme for soybean meal in autumn and winter and huabei district was higher than others. The detection rate of Aspergillus flavus for DDGS was very low, but the detection rate of Fusarium moniliforme was higher, especially for autumn and huazhong district, the detection rate was 40. 4%and 50. 0%, respectively., Conclusion: The feed ingredients from China were commonly contaminated by fungi. It is recommended that strengthening the fungi contamination monitoring of feed ingredients from summer and autumn, huabei and huazhong district was an important prevention method.

Objective: To survey the fungi contamination of different feed ingredients in China., Methods: Soybean meal, cottonseed meal, wheat bran and distillers dried grains with soluble (DDGS) were collected from feed enterprises in different part of the country. Feed ingredient samples were diluted and inoculated and the key factors were screened which influenced the isolation., Results: Potato dextrose agar (containing chloramphenicol 0.1 g/L) and 10(-1) dilution were the optimum culture medium and dilution respectively. The range of fungi contamination was from 31% (DDGS) to 88% (wheat bran). The fungi contamination frequencies of feed ingredients varied from region to region, and varied from kind to kind. The contamination of Aspergillus flavus and Fusarium spp. were also different in the regions and sample types. The average contamination percentage of Aspergillus flavus (25%) is higher than Fusarium spp. (11%), and their contamination level is highest in northeast China and lowest in south China, wheat bran and cottonseed meal were the highest and DDGS was the lowest., Conclusion: The fungi contamination, including Aspergillus flavus and Fusarium spp. of feed ingredients all over the country should be pay more attention. It is recommended that prevention of feed ingredients from fungi contamination is needed.

Objective: To identify the aflatoxins contamination of corn in China., Methods: Aflatoxins B1, B2, G1 and G2 in 279 corn samples collected from 6 provinces or autonomous regions were determined by HPLC., Results: Aflatoxins were detected in 75.63% of 279 corn samples. The average concentration of positive samples was 44.04 microg/kg, with a range of 0.20 - 888.30 microg/kg. The positive rates of samples from Sichuan, Hubei, Guangxi, Henan, Guangdong and Jilin Provinces were 90.48%, 93.75%, 87.50%, 36.96%, 91.84% and 52.17% respectively, with an average concentration of 107.93, 70.98, 39.65, 8.06, 3.70 microg/kg, and 1.15 microg/kg respectively. AFB1 was detected more frequently and with higher levels than the other three aflatoxins, with a positive rate of 74.55% and an average concentration of 39.64 microg/kg. The positive rate of AFB2, AFG1 and AFG2 was 58.42%, 41.22% and 19.71% respectively, and the average concentration of them was 3.81, 3.47 and 0.51 microg/kg respectively., Conclusion: Corn samples collected from all six regions are contaminated widely with aflatoxins in various degrees. The contamination of aflatoxins in the South was more serious than that in the North of China. AFB1 is the prominent one among the four aflatoxins.