2021 Vol. 36, No. 6
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Using the pit mud samples collected from six Baijiu production companies of He'nan province as research objects, and the moisture content, pH value, total acid, ammonium nitrogen and available phosphorus were determined and analyzed. The results suggested that the average moisture content, pH value, total acid, ammonium nitrogen and available phosphorus of above pit muds were 39. 21%, 5. 36, 7. 51 mg/g, 699. 0 mg/kg and 214. 7 mg/kg, respectively. The moisture contents of pit mud samples from company (SH) in the east of He'nan province and the pH value and ammonium nitrogen content of samples from company (JH) in the central area of He'nan province were all significantly higher than those of other companies. Moreover, the total acid content of samples from companies in the west (YS) and north (BQC) of He'nan province was significantly higher, while the effective phosphorus content of YS was significantly higher. The physicochemical factors of the pit muds from the company in the same region clustered together, which suggested the regional differences in the physical and chemical properties of pit muds within He' nan province. Among them, pH value, ammonium nitrogen, total acid and moisture content could be the main physicochemical factors which caused the regional difference. There were correlations between the physicochemical factors, among which ammonium nitrogen was significantly positively correlated with moisture content and pH value, while significantly negatively correlated with total acid.
The physicochemical indexes of bag Daqu and brick Daqu were studied. With high-throughput sequencing technology the bacterial community structure of bag Daqu and brick Daqu samples were analyzed. The results showed that the moisture content, acidity, starch content and other physicochemical indexes of brick Daqu and bag Daqu were within the standard range of finished Daqu. Compared with bag Daqu, the moisture content and fermentation power of brick Daqu were higher and the difference was significant;the saccharification power, liquefaction power, esterification power and fermentation power brick Daqu were higher, the acidity and starch content of brick Daqu were lower and the difference was very significant;the starch content was not much different. With the average relative abundance of 0. 05% as the threshold, the dominant bacteria of the bag Daqu and brick Daqu were Proteobacteria, Firmicutes and Actinobacteria. There was one more Bacteroidetes in the dominant bacteria of he brick Daqu than in bag Daqu. With the average relative abundance of 1. 00% as the threshold, the predominant bacterial genus of bag Daqu were Pseudomonas, Pantoea, Acinetobacter, Leuconostoc, Lactobacillus, and the predominant bacterial genus of brick Daqu were Lactobacillus, Leuconostoc, Pantoea, Klebsiella, Pseudomonas, Staphylococcus, Lactococcus. In this study, Barnesiella was discovered from the brick Daqu for the first time.
By using the culturable method and 16S rRNA sequence analysis, the anaerobic strains were isolated from the pit mud of five strong-flavor Baijiu companies in Henan Province and their volatile metabolites were studied. The highest similar bacteria of the 138 pure cultures assigned into 8 genera of classes of Clostridia and Bacilli, a total of 30 species, including 15 species of Clostridia and 15 species of Bacilli. Among them, the species of Paraclostridium benzolyticum, Terrisporobacter petroearius, etc. were also isolated, which were rarely reported. The volatile substances in the fermentation broth of the above 30 representative strains were mainly acids and alcohols, including important aroma substances and precursors in strong-flavor Baijiu, such as caproic acid, butyric acid and butanol. Clostridium tyrobutyricum,Clostridium sporogenes,Clostridium butyricum,Clostridium botulinum,Trichobacterium petroleum,Paraclostridium benzolyticum,Trichobacterium glycolicus, Clostridium aestuarii, Bacillus licheniformis, Paenibacillus faecis, Bacullis fumarioli,Staphylococcus hominis and Bacillus haynesii had positive correlations with the 41 volatile metabolites, indicating that they could contribute to the flavor formation of strong-flavor Baijiu.
This study aimed to investigate the effects of different mass fractions of Chickpea Protein Isolate (CPI) on the emulsifying property of pork myofibrillar protein. The results showed that the EAI, ESI and rheological storage modulus G' of pork myofibrillar protein emulsion increased gradually with the increase of the addition of CPI. When the addition of CPI was 1. 2%,the EAI and storage modulus G' of pork myofibrillar protein emulsion reached the maximum,and the total stable index and emulsification both reached the minimum. The results indicated that adding 1. 2% CPI could effectively improve the emulsification properties of pork myofibrillar protein, and enhance the stability of pork myofibrillar protein emulsion.
Based on the classification and overview of the four biological preservatives of plant orgin, animal origin, microbial origin and enzymes, the combined application of the technology of biological preservatives and other preservation technology were combed. It was pointed out that plant origin biological preservatives were the most common, but their chemical composition was complicated and their inhibitory concentration was difficult to control. The animal origin biological preservatives had good antibacterial effects, but the cost was high and extraction rate was low, mainly through synergistic effect with other preservatives. The biological preservatives derived from microorganisms were safe and efficient, but they showed a narrow antimicrobial spectrum. The enzymatic biological preservatives had good preservation effect, but had narrow antimicrobia spectrum, difficult extraction and high cost. Better preservation effect could be obtained by compound biological preservatives with refrigerated preservation and air-conditioned packaging preservation. In view of this, while looking for abundant sources of inexpensive natural biological preservatives, it is necessary to improve the technical standard system of natural biological preservative, drawing lessons from the international latest research progress and related specification, to strengthen the research of preservation mechanism, to explore and design more efficient biological preservation technology, so as to provide security for poultry products of industrialization production.
An aroma-producing strain MG6 with aroma production was isolated from the surface of sunny rose grape. The strain was identified and the characteristic aroma components of its fermentation broth were analyzed. Then the tobacco flavor was prepared by the strain and the aroma evaluation of cigarette was carried out. The results showed that the strain was Pichia terricola. Compared with the control group, the main characteristic aroma components such as ketones, alcohols, esters, phenols and olefins in the fermentation broth of the strain were significantly increased, and the total contents of megastigmatrien-3-one, dihydrokiwifruit lactone and neophytadiene were increased in different degrees, which were particularly important for improving the aroma quality of tobacco. When the added amount of tobacco flavoring was 0. 05%, the quality and amount of aroma were improved, the irritation was reduced, and the overall sensory quality was improved.
In order to improve the utilization rate of tobacco stems and the processing quality of stem shreds, the processing parameters of tobacco stems sorting, steam and microwave co-expansion, expanded tobacco stem remoisture, tobacco stem recutting, airflow drying and other key process parameters in the processing of microwave expanded tobacco stem shreds were studied. The optimal process parameters were as follows:tobacco stem sorting process selected short stems with a length of ≥ 2 cm and fine stems with a diameter of ≥ 3. 0 mm. The material flow rate in the steam-microwave co-expansion process was set at 240~270 kg/h, the superheated steam flow rate was 950~1050 kg/h, the cavity temperature was 148~151℃, and the microwave power was between 36~39 kW. When the water washing time in the moisture regaining process of expanded tobacco stems was greater than 50 s, the moisture content of Conditions was 30. 5% The storage time after conditioning was not less than 4 hours. The combination method of front high and low back was used in the re-cutting process of tobacco stems. The slice thickness was 0. 60 mm, the cutting width was 0. 30 mm, the knife door pressure was 30~35 kN, and the knife roller rotation speed was within the range of 400~450 r/min. The material flow rate was 150 kg/h, the process gas flow rate was 6500 m3/h, and the temperature was 196℃. The width of the stalk processed by the silk-making process was closer to that of the leaf stalk, the stalk structure was more uniform, and the overall quality of the stalk was better.
A series of coatings with high barrier properties were prepared by using environmental-friendly polymer material polyvinyl alcohol as matrix and modified by natural lipid. Cigarette packet blanks were coated with the prepared coating solutions, the water vapor barrier of the blanks was tested before and after coating. In addition, the effects of coating on the physical moisture retentivity, moisture resistance and flavor keeping performance of cigarettes were studied. The results showed that compared with the uncoated blanks, the water vapor transmission rates of coated blanks significantly decreased with the largest drop of 83. 23%; under the same conditions, the total moisture loss in dry environment and the total moisture absorption amount in humid environment of the cigarettes packed in a packet with a coated blank decreased by 16. 81% and 18. 03% respectively. In conclusion, the water vapor barrier of packet blank was increased by coating, and the physical moisture retentivity and moisture resistance of cigarettes were significantly promoted accordingly. Moreover, the flavor keeping performance and sensory quality of cigarettes were also improved obviously.
In the three-phase four-wire power distribution system of modern cigarette workshops, the zerosequence current causes the midpoint voltage fluctuation on the DC side, which affects the harmonic control effect of active power filter (APF). To solve this problem, a model predictive reconstructed space voltage vector control strategy based on neutral point clamped (NPC) three-level APF was proposed. The APF harmonic control hierarchy analysis framework was constructed, the three performance indicators of midpoint voltage balance, zero sequence current compensation and space voltage vector utilization were designed, and the performance of various voltage vector indicators was evaluated. The 6 types of reconstructed space voltage vector combinations were quantitatively compared, and the combination with the highest evaluation score in the analytic hierarchy process was selected for model predictive harmonic control. Simulation and experimental results showed that compared with conventional control strategies, the proposed strategy could effectively control harmonics and balance the midpoint voltage of the DC side of the APF.
In order to solve the problems of the non-slip belt conveyor in the tobacco primary processing line of cigarette factory, such as the breeding of tobacco insects, the low efficiency of personnel cleaning, an automatic cleaning device for the non-slip belt conveyor was designed. The device was installed under the non-slip conveyor belt. In the automatic cleaning mode, its lifting mechanism controlled the brush lifting. High frequency and high pressure atomized water was used to clean the surface of the conveyor belt. The surface of the belt was blown dry with high pressure air. The application results showed that using this device to clean the non-slip belt conveyor could effectively control the tobacco insects, improve the internal quality of the product, reduce the number of cleaning personnel and safety hazards of the silk production line equipment, and improve the operation efficiency of the equipment.
With carbon cloth (CC) as a substrate, the composite of CC/TiO2/Ag@AgCl was successfully prepared via a successive chemically coupled method, in-situ deposition method and the followed photogenic reduction method. The adsorption-photocatalytic degradation activities and the photoelectric properties of CC/TiO 2/Ag@AgCl were further studied. The results indicated that 96. 9% of RhB could be captured and degraded in the presence of CC/TiO2/Ag@AgCl composites under 120 min UV-vis irradiation, which was higher than those of pure TiO2(83. 8%) and Ag@AgCl (78. 6%). It was verified that CC/TiO2/Ag@AgCl catalyst broadened the light absorption range and showed more efficient photocarrier separation and transfer efficiency, which was beneficial to inhibit the electron-hole pair recombination and the improvement of photocatalytic activity. The capture of active pieces experiments indicated that the free ·OH radicals and ·O2- radicals were the main active oxidizing species involved in the RhB photoreaction process of CC/TiO2/Ag@AgCl.
Ag/g-C3N4 was synthesized by a photo-reduction method in the presence of g-C3N4 as the photocatacytic material and polyvinylpyrrolidone as an inhibitor. The degradation effect and mechanism of sulfamerazine by Ag/g-C3N4 was studied in the presence of visible lightir irradiation. The results indicated that sulfamerazine could be effectively degraded by Ag/g-C3N4. The degradation rate of sulfamerazine was 97. 3% after being irradiated for 30 min. Photogenerated hole and ·O2- were the main active species, which could regrade sulfamerazine by the cleavage of S-N bond, the hydroxylation of the benzene ring, the nitration of amino and the carboxylation of methyl.
Self-healing hydrogels based on dynamic covalent bonds or noncovalent interactions and their applications in wound dressing, drug delivery, tissue engineering, bionic electronic skin and wearable electronic devices were reviewed in this paper. The commonly used self-healing mechanisms for preparing self-healing hydrogels were represented in detail. At the same time, as self-healing hydrogels under solo dynamic covalent bonds or noncovalent interaction mechanisms had some shortcoming, such as weak mechanical properties, rigor self-healing conditions, incomplete recovery, and so on, the research direction of designing of self-healing hydrogels in the future was pointed out such as, design of self-healing hydrogels with self-healing behavior in various environments,self-healing hydrogels combined with dynamic covalent/non-covalent interactions,selfhealing hydrogels for flexible electronic devices,and so on, which aimed to achieve the rapid development of multi-mechanism and multi-functional self-healing hydrogels, and promote its effective application in biomaterials and soft intelligent materials.
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Administered by:The Education Department Henan Province
Sponsored by:Zhengzhou University of Light Industry
Editor-in-chief:Wei Shizhong
Executive Editor-in-Chief:Zou Lin
Deputy Editor-in-Chief:Qu Shuanghong
Edited & published by:Editorial Department of Journal of Light Industry
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ISSN 2096-1553
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