Retraction Note to: Effects of dietary glycerol monolaurate on productive performance, egg quality, serum biochemical indices, and intestinal morphology of laying hens.

Retraction Note to: J Zhejiang Univ-Sci B (Biomed & Biotechnol) 2019 20(11):877-890. https://doi.org/10.1631/jzus.B1800530. The authors have retracted this article (Zhao et al., 2019) due to significant overlap with a previously published Chinese language article (Liu et al., 2017), including overlap in Table 1, Table 2, Table 3, Table 6, Fig. 4, and part of the results (Sections 3.1, 3.2, 3.5, and 3.7). All authors agree with this retraction.

Effects of dietary glycerol monolaurate on productive performance, egg quality, serum biochemical indices, and intestinal morphology of laying hens.

Glycerol monolaurate (GML) has been widely used as an effective antibacterial emulsifier in the food industry. A total of 360 44-week-old Hy-Line brown laying hens were randomly distributed into four groups each with six replicates of 15 birds, and fed with corn-soybean-meal-based diets supplemented with 0, 0.15, 0.30, and 0.45 g/kg GML, respectively. Our results showed that 0.15, 0.30, and 0.45 g/kg GML treatments significantly decreased feed conversion ratios (FCRs) by 2.65%, 7.08%, and 3.54%, respectively, and significantly increased the laying rates and average egg weights. For egg quality, GML drastically increased albumen height and Haugh units, and enhanced yolk color. Notably, GML increased the concentrations of polyunsaturated and monounsaturated fatty acids and reduced the concentration of total saturated fatty acids in the yolk. The albumen composition was also significantly modified, with an increase of 1.02% in total protein content, and increased contents of His (4.55%) and Glu (2.02%) under the 0.30 g/kg GML treatment. Additionally, GML treatments had positive effects on the lipid metabolism of laying hens, including lowering the serum triglyceride and total cholesterol levels and reducing fat deposition in abdominal adipose tissue. Intestinal morphology was also improved by GML treatment, with increased villus length and villus height to crypt depth ratio. Our data demonstrated that GML supplementation of laying hens could have beneficial effects on both their productivity and physiological properties, which indicates the potential application of GML as a functional feed additive and gives us a new insight into this traditional food additive.

Screening, purification, and characterization of an extracellular lipase from Aureobasidium pullulans isolated from stuffed buns steamers.

An extracellular lipase from Aureobasidium pullulans was obtained and purified with a specific activity of 17.7 U/mg of protein using ultrafiltration and a DEAE-Sepharose Fast Flow column. Characterization of the lipase indicated that it is a novel finding from the species A. pullulans. The molecular weight of the lipase was 39.5 kDa, determined by sodium dodecyl sulfonate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme exhibited its optimum activity at 40 °C and pH of 7. It also showed a remarkable stability in some organic solutions (30%, v/v) including n-propanol, isopropanol, dimethyl sulfoxide (DMSO), and hexane. The catalytic activity of the lipase was enhanced by Ca2+ and was slightly inhibited by Mn2+ and Zn2+ at a concentration of 10 mmol/L. The lipase was activated by the anionic surfactant SDS and the non-ionic surfactants Tween 20, Tween 80, and Triton X-100, but it was drastically inhibited by the cationic surfactant cetyl trimethyl ammonium bromide (CTAB). Furthermore, the lipase was able to hydrolyze a wide variety of edible oils, such as peanut oil, corn oil, sunflower seed oil, sesame oil, and olive oil. Our study indicated that the lipase we obtained is a potential biocatalyst for industrial use.

Mechanisms of Nα-lauroyl arginate ethyl ester against Penicillium digitatum and Pectobacterium carotovorum subsp. carotovorum.

The purpose of this study was to investigate the antimicrobial activity and mechanisms of Nα-lauroyl arginate ethyl ester (LAE) against Penicillium digitatum and Pectobacterium carotovorum subsp. carotovorum. The minim inhibitory concentrations of LAE against P. digitatum and P. carotovorum were found to be 400 and 25 µg/ml, respectively. Loss of intracellular protein and nucleic acid increased significantly, and membrane permeability reached 76.28, 54.29 and 85.20%, respectively, when 400 µg/ml of LAE was applied to the hyphae and spores of P. digitatum and to P. carotovorum. Flow cytometry showed that LAE reduced the membrane potential, and the depolarization ratios of P. digitatum and P. carotovorum were 98.19 and 97.25% (P < 0.05), respectively. Transmission electron microscopy photos revealed that LAE caused a rough surface, irregular cellular organelles, protoplast shrinkage, intracytoplasmic coagulation and empty cavities in all three cell types. These results showed that LAE had notable ability to damage the structure of fungal and bacterial cells, making it a possible alternative chemical for use in the preservation of fruits and vegetables.

Quantitative structure-activity relationships of antimicrobial fatty acids and derivatives against Staphylococcus aureus.

Fatty acids and derivatives (FADs) are resources for natural antimicrobials. In order to screen for additional potent antimicrobial agents, the antimicrobial activities of FADs against Staphylococcus aureus were examined using a microplate assay. Monoglycerides of fatty acids were the most potent class of fatty acids, among which monotridecanoin possessed the most potent antimicrobial activity. The conventional quantitative structure-activity relationship (QSAR) and comparative molecular field analysis (CoMFA) were performed to establish two statistically reliable models (conventional QSAR: R(2)=0.942, Q(2)(LOO)=0.910; CoMFA: R(2)=0.979, Q(2)=0.588, respectively). Improved forecasting can be achieved by the combination of these two models that provide a good insight into the structure-activity relationships of the FADs and that may be useful to design new FADs as antimicrobial agents.

[Rapid measurement of citric acids in orange juice using visible and near infrared reflectance spectroscopy].

Visible and near infrared reflectance spectroscopy (Vis/NIRS) as a new method was proposed for the rapid and nondestructive measurement of citric acids in orange juice. High performance liquid chromatography (HPLC) was used as a reference method for the spectral analysis of citric acids. The original spectral data were preprocessed by the smoothing method with five smoothing points in order to eliminate the noise. Before modeling, large spectral data were compressed by wavelet transform (WT) in Matlab7.01 with the edited program to reduce the dimensions and modeling time, and then the new variables after being compressed were used to build PLS calibration in spectral software Unscrambler 9.5. Considering the effect of different wavelet functions and decomposed scales on the data compressed, the optimal wavelet function Db4 and decomposed scale 5 were determined by predictive residual error sum of squares (PRESS). A total of forty samples were used in our experiment, including thirty samples for the calibration model and ten unknown samples for the prediction. The quality of the calibration model was evaluated by the correlation coefficients (r) and standard error of calibration (SEC), and the prediction results were assessed by correlation coefficients (r) and standard error of prediction (SEP). Comparing WT-PLS model with PLS model, the result of WT-PLS model was r of 0.901 and SEP of 0.937, while the result of PLS model was r of 0.849 and SEP of 1.662, indicating that the prediction result from PLS model with wavelet transform was better than that from PLS model.

Nutritional evaluation of different bacterial douchi.

The aim of this study was to determine the content and/or composition of protein, peptide, amino acid, lipid and fatty acid in bacterial douchi (BD) made by different pure starter fermentation. Protein content of BD3, BD5, BD7 and BD8 was significantly higher than that of autoclaved soybean (AS). Lipid content of BD1, BD5 and BD6 was also significantly higher than that of AS. Predominant amino acids were glutamic acid (11.3-15.2%), proline (11.2-14.5%), aspartic acid (8.7-10.0%), leucine (9.2-10.0%) and alanine (7.4-8.9%). BD had EAA7 and EAA9 values of 34.4-36.4% and 40.5-41.7% respectively. Threonine with the amino acid score of 61-85 was the limiting amino acid. Triacylglycerol (82.4-88.2%) was the most abundant lipid in BD, followed by phospholipid (9.6-16.4%) and phytosterol (1.2-2.9%). Major fatty acids were palmitic (10.6-11.3%), oleic (20.5-21.9%), linoleic (54.2-55.6%) and alpha-linolenic acid (8.2-9.1%). The ratio of n-6 polyunsaturated fatty acids (PUFA) to n-3 PUFA ranged from 6.1 to 6.7. Amino acid nitrogen and trichloroacetic acid soluble protein increased from 0.2% (AS) to 1.8% (BD8) and from 1.3% (AS) to 4.0% (BD7) at the highest level respectively. Peptides with molecular weight < or = 2000Da accounted for at least 75% of total peptide. Bacterial fermentation of soybean increased amino acid nitrogen and trichloroacetic acid soluble protein except BBDC6, decreased molecular weight of 100-500 and increased 500-1000 and 2000-5000 peptides. Composition of lipids, fatty acids, and amino acids were no significant change after soybean bacterial fermentation.

[Analysis of ant oil extracted with supercritical CO2 fluid from Polyrhachis vicina by GC-MS].

OBJECTIVE: To study the optimum extraction parameters and components on ant oil from Polyrhachis vicina. METHOD: The optimum condifious for supercritical CO2 fluid extraction (SFE-CO2), were investigated with orthogonal design, GC-MS was applied for analyzing. The components and their contents in the ant oil were analyzed by GC-MS, and the contents of lead, zinc and manganese in the oil were determined by ICP-AES. RESULT: The optimum extraction parameters were achieved, temperature of 50 degrees C, pressure of 30 MPa and time of 2 hours. The extracting yield of the ant volatile oil was 11.4% - 14.3%. 51 Constituents were identified including 9-octadecenoic acid, ethyl oleate, cholesterol, n- Hexadecanoic acid, etc, and the content of various constituents was determined by orea normalization. The oil contained unsaturated fatty acid of 64.6%, lead of 0.80 microg x g(-1), zinc of 0.54 microg x g(-1) and manganese of 0.15 microg x g(-1). CONCLUSION: The method showes advantages including faster and efficient of extraction, good quality and no solvent residues in the oil.