2025 Vol.32(5): 1–5    [Abstract] ( 40 )    [PDF 854 KB ] ( 25 )

Sanxan is an exopolysaccharide synthesized by fermentation of Sphingomonas sanxanigenens. The acyl groups on the side chain of Sanxanigenens have important influence on the properties of Sanxan gum. In order to investigate the effect of acyl content on the rheological properties of Sanxan gum, deacylated Sanxan gum with different acyl content was prepared by alkali treatment. The content of acyl group in Sanxan gum samples with different alkali treatment time was determined, and the rheological properties of Sanxan gum samples with different acyl group content were studied during room temperature, gelation and melting process. The results showed that although the time of deacylation treatment had little effect on the change of acyl content, the acyl content of trisangel gradually decreased with the extension of the treatment time.The viscosity of natural Sanxan was higher than that of deacylated Sanxan at room temperature. In the process of gelling and melting, the temperature difference of natural Sanxan is larger, and the thermal hysteresis phenomenon is more obvious. In the temperature range of 10 ℃—90 ℃— 10 ℃, the DSC curve of natural Sanxan changes more significantly. The results showed that the existence of acyl group made the double helix structure of Sanxan gum aggregate faster and more stable, which provided a basis for the application, product improvement, technical innovation and popularization of Sanxan gum in food and other fields.

2025 Vol.32(5): 6–11    [Abstract] ( 35 )    [PDF 1726 KB ] ( 11 )

In this study, ‘Jinli No. 3 'Chenopodium quinoa cabbage were used as the experimental material. Cell disruption was achieved using ultrasonic-assisted extraction, and alkaline extraction-acid precipitation method was employed to extract soluble proteins from quinoa cabbage. The extraction process of quinoa cabbage protein was optimized. The effects of temperature, liquid-to-material ratio, extraction time, and pH on the extraction rate were explored using single-factor experiments combined with response surface methodology. The optimal extraction conditions for Jinli No. 3 C. quinoa cabbage protein was determined as follows: temperature of 35 ℃, liquid-to-material ratio of 1∶40（g/mL）, extraction time of 1.5 h, and pH of 4.5±0.05. The maximum extraction rate of C. quinoa cabbage protein could reach 55.01%. The results of this study can provide experimental basis for the development and utilization of chenopodium quinoa cabbage protein.

2025 Vol.32(5): 12–17    [Abstract] ( 27 )    [PDF 673 KB ] ( 6 )

Through two consecutive years of pot experiments, the effects of different amounts of black soldier fly frass（2%, 4%, 6%）application on the growth of Brassica chinensis and soil physicochemical properties were studied, with no fertilization as the control（CK）. The results showed that compared with CK, the application of black soldier fly frass reduced soil pH, increased soil organic matter content（4.5%-49.5%）, EC value（34.4%-814.1%）, alkaline nitrogen content（20.6%-76.8%）, available phosphorus content（11.4%-64.6%）, and available potassium content（78.9%-542.1%）; The organic matter, EC, and nutrient content of the soil in the second year of the same treatment were lower than those in the first year. The application of frass fertilizer increased the activities of soil urease, phosphatase, catalase, and sucrase. The overall soil nutrients and enzyme activity increased with the increase of frass application, with 6% application rate treatment>4% application rate treatment>2% application rate treatment. The application of frass fertilizer promoted the growth of Brassica chinensis. In the first year, the treatment with a 4% application rate resulted in the highest plant height of Brassica chinensis, which was 61.8% higher than CK. There was no significant difference in yield between the 6% application rate and the treatment. However, in the second year, the treatment with a 6% application rate resulted in the highest plant height and yield of Brassica chinensis. In summary, the application of black soldier fly frass can improve soil fertility, promote crop growth, and have strong seasonal and subsequent fertilizer effects.

2025 Vol.32(5): 18–23    [Abstract] ( 30 )    [PDF 616 KB ] ( 6 )

To solve the problem of increasing soil salinization, the effects of exogenous salicylic acid and chitosan on the physiological characteristics of Vicia villosa Roth seedlings were studied. ‘Tianshi 2' V. villosa Roth as the material, with 1 mmol/L salicylic acid and 0.30% chitosan treated, under different salt-containing soil conditions, catalase activity, superoxide dismutase activity, soluble sugar content, soluble protein content, proline content and malondialdehyde content. Were deter mined. Conpared with the contrd greup, the cidalase activity, super c side disrn utase activity, soluble sugur conreit, soluble prolein content and proune content of 1 mmol/L solicguc acid and 0.30% chitosan treated V. Viuosa Roth seedling increased 8.37% and 9.43%, 7.45% and 8.41%, 4.21% and 11.73%, 32.01% and 38.50%, 9.52% and 11.90%（P<0.05）respeetively under 0.38% salt centent. The content of malondialdehyde was decreased by 15.06% and 17.85%（P<0.05）, respectively. The content of soluble sugar and soluble protein of V. villosa Roth seedling treated with 0.30% chitosan were higher 8.25% and 13.90%（P<0.05）than control respectively under 0.70% salt content. There was no significant difference in the contents of the two substances between the 1 mmol/L salicylic acid treatment and control of V. villosa Roth seedlings under 0.70% salt content. Salicylic acid and chitosan can effectively alleviate the impact of salt stress on the seedlings of V. villosa Roth seeds, and the degree of 0.30% chitosan is better than 1 mmol/L salicylic acid.

2025 Vol.32(5): 24–30    [Abstract] ( 117 )    [PDF 1809 KB ] ( 14 )

In order to establish a loose embryogenic callus induction system of Apium graveolens and obtain somatic embryogenesis, different explants of Apium graveolens were used to induce callus and somatic cell embryogenesis on the medium containing 2,4-D. The results showed that the hypocotyl of Apium graveolens as an explant can induce ideal callus tissue; The callus grew fastest on MS+0.5 mg/L KT+0.2 mg/L NAA+1.0 mg/L 2,4-D medium; Loose callus can be induced on MS+0.5 mg/L KT+0.5 mg/L 2,4-D medium; Transfer loose embryogenic callus tissue to MS+0.1 mg/L KT+0.5 mg/L 2,4-D medium, subculture every 15 days, and obtain loose embryogenic callus tissue after 3 subcultures; The loose embryogenic callus was transferred to MS+0.25 mg/L KT+0.25 mg/L 2,4-D medium and subcultured once every 15 days. After subculturing for three times, the Apium graveolens somatic cell embryos were obtained; After somatic embryos were transferred to 1/2MS medium, regenerated plants of Apium graveolens could be obtained after 45 days. This experiment successfully established the induction system of loose embryogenic callus and somatic embryogenesis of Apium graveolens, and obtained regenerated plants, which laid a certain foundation for in vitro mutation breeding of Apium graveolens somatic cell.

2025 Vol.32(5): 31–38    [Abstract] ( 28 )    [PDF 832 KB ] ( 5 )

In order to investigate and analyze the key aroma substances composition of seedlings and tender spikes in quinoa. The differences of key flavor substances between seedlings and tender spikes in quinoa were compared and analyzed, and the sensory characteristics of key flavor substances between seedlings and tender spikes in quinoa were clarified, solid-phase microextraction-gas chromatography-mass spectrometry（SPME-GC-MS）was used to analyze the composition of volatile substances in quinoa seedlings and quinoa spikes in this study, and the relative odor activity value（ROAV）was used to calculate the composition of key aroma substances. The results showed that a total of 123 volatile substances were identified from quinoa seedlings and quinoa spikes. In quinoa seedlings, the content of alcohols is the highest（43.54%）. In quinoa spikes, the content of esters is the highest（15.57%）. The volatile substances of quinoa seedlings and quinoa spikes differed greatly. Seedlings and tender spikes of quinoa contained only two compounds in common, namely（E）-hexene-1-ol and hexadecane, and amines and ethers existed only in quinoa spikes. The ROAV analysis showed that（E）-3-hexen-1-ol was the most flavor-contributing substance in quinoa seedlings and quinoa spikes. In addition, D-limonene, 2-ethylhexanol, and methyl salicylate, the key aroma substances, played important roles in the formation of distinctive aromas in quinoa seedlings and quinoa spikes, respectively. There are many kinds of volatile substances in the seedings and tender spikes in quinoa, which is beneficial to improve the taste and quality of seedings and tender spikes in quinoa. The key flavor substances, such as aldehydes and esters, make seedings and tender spikes in quinoa have unique aroma and flavor. These results provide reference for the further development and utilization of quinoa seedlings and quinoa spikes.

2025 Vol.32(5): 39–46    [Abstract] ( 26 )    [PDF 859 KB ] ( 9 )

Typhoon Doksuri caused extreme rainfall in the Beijing-Tianjin-Hebei region, and the Haihe River had a large regional flood. As the artificial flood drainage channel of the lower reaches of Daqing River in the Haihe River basin, the Duliujian River is responsible for the important task of discharging flood into the sea. The influx of flood made the salinity of the coastal waters decrease rapidly, which seriously affected the ecological environment of the sea area and the beach in the estuary area. Shellfish play an important role in the benthic ecosystem of the intertidal zone in the estuary area, and play an important role in the material circulation and energy flow of the Marine ecosystem. In order to understand the impact of the super typhoon on the intertidal shellfish resources in the river estuary, 15 sampling points in this area were investigated in the early, middle and later stages of flood discharge. The results showed that the salinity of the sea water in this area decreased from 20 to about 13, and finally recovered to 25. A total of 17 species of shellfish were found in the three surveys, belonging to 2 classes, 3 subclasses, 9 orders and 13 families. The shellfish species obtained from the three surveys were 15, 8 and 8 kinds, respectively. The biomass of the three surveys were 252.77 g/m2, 352.56 g/m2 and 845.66 g/m2, respectively. Diversity index H´ : late flood discharge>middle flood discharge>early flood discharge; Richness index D: early flood discharge>middle flood discharge>late flood discharge; Evenness index J: late flood discharge>middle flood discharge>early flood discharge. Affected by the flood discharge, the species and distribution characteristics of the intertidal shellfish fluctuated, and the biomass was greatly affected in the early and middle period of the flood discharge, but the dominant economic shellfish, Mactra veneriformis, was less affected by the flood discharge, and recovered quickly in the late period of the flood discharge, with the biomass reaching 712.65 g/m2. The results of this survey can provide reference for the assessment of the damage caused by Typhoon Doksuri to the shellfish resources in Tianjin, and also provide a theoretical basis for the subsequent restoration and value-added release of shellfish resources.

2025 Vol.32(5): 47–56    [Abstract] ( 31 )    [PDF 3173 KB ] ( 6 )

This study aimed to clarify the changes of microbial diversity in the circulating water pond of channel catfish from July to September, and the changes of physical and chemical factors and their correlation. In the study, a high-throughput sequencing method was used to analyze the environmental microecology of a channel catfish pond in Tianjin, and the water physical and chemical indexes of the aquaculture area and filtration area were determined to analyze the correlation between them. The results showed that the microbial diversity and richness of sediment and that of brush samples in the channel catfish aquaculture pond were higher than those in the water. Among them, the microorganisms in sediment and brush samples had high similarity but low similarity with those in water. Ilumatobacteraceae of Actinobacteria had a significant negative correlation with total phosphorus, which has the potential to be used as an indicator of total phosphorus content in water（P<0.05）. There was a very significant positive correlation between the Caldilineaceae family and nitrite nitrogen, and it can regulate nitrite nitrogen in the water（P<0.01）. Ammonia nitrogen had a significant effect on the bacterial community structure of sediment（P<0.05）. The results provide a reference for the microecology and water quality control of the same type of channel catfish during aquaculture.

2025 Vol.32(5): 57–63    [Abstract] ( 26 )    [PDF 1149 KB ] ( 8 )

To mitigate the toxic effects of microcystin（MCs）pollution in aquaculture waters on shrimp, this study isolated five anaerobic MCs-degrading bacterial strains from the intestines of shrimp cultured in Microcystis-blooming pond through selective enrichment culture. The strains were identified using morphological observation, physiological and biochemical characterization, and 16S rRNA gene sequence analysis, followed by evaluation of their degradation performance. Results showed that five MCs-degrading strains were identified as Shewanella algae, Serratia marcescens, Citrobacter amalonaticus, Exiguobacterium mexicanum, and Bacillus flexus. The MCs-degrading efficiency of the five strains followed the descending order: B. flexus>E. mexicanum>S. marcescens>C. amalonaticus>S. algae. Under an initial MCs concentration of 390.17 μg/L,B. flexus and E. mexicanum （4.5×108 CFU/mL） achieved complete MCs degradation within 48 h, while S. marcescens（at the same cell density）required 72 h for complete degradation. Among the five bacteria strains, B. flexus and S. marcescens show potential as feed additives for MCs pollution control in shrimp aquaculture.

2025 Vol.32(5): 64–70    [Abstract] ( 21 )    [PDF 1239 KB ] ( 7 )

The black soldier fly larvae（BSFL）（Hermetia illucen）,as an emerging resource-based insect, efficiently converts organic waste into organic matter such as protein and fat. To investigate the effects of different feeding substrates on nutritional composition changes in Hermetia illucens larvae, this study employed meta-analysis to synthesize domestic and international literature data on feeding black soldier flies with diverse substrates（including food waste, livestock manure, animal feed, fruit and vegetable waste, and other categories）. The analysis investigated variations in key nutritional components within the insects, such as crude protein, crude fat, and ash content. Results indicate significant differences（P<0.05）in nutritional content among BSFL reared on different substrates. Those fed animal feed exhibited the highest crude protein content, while those fed food waste and fruit/vegetable waste showed significantly higher crude fat content（P<0.05）compared to the other three groups. The poultry manure group exhibited the highest ash content. Overall, the nutritional content within BSFL is closely related to their feeding substrate. Different materials such as poultry manure, fruit and vegetable waste, and food waste exhibit distinct differences in composition and characteristics. These variations may influence the nutrient uptake and conversion processes in BSFL.

2025 Vol.32(5): 71–78    [Abstract] ( 30 )    [PDF 1515 KB ] ( 11 )

The drying of agricultural products is a key link to ensure food safety and improve storage and transportation efficiency. The intelligent and efficient control system has become an important means to ensure the drying quality of agricultural products and reduce energy consumption. This paper reviews the transformation process of drying technology from conventional control method to intelligent control method, introduces typical application cases of various control systems in detail, analyzes and compares the advantages and limitations of conventional control system and intelligent control system, in order to provide reference for the selection of drying process control system and accurate control of drying process and promote the drying process of agricultural products in a more efficient, intelligent and environmentally friendly direction.

2025 Vol.32(5): 79–87    [Abstract] ( 26 )    [PDF 3041 KB ] ( 10 )

Based on the annual precipitation data of Tianjin urban area from 1890 to 2022 for 133 years, P-Ⅲ frequency analysis, linear trend, 5-year moving average, cumulative anomaly, Mann-Kendall test, and wavelet analysis were used to analyze the statistical characteristics, evolutionary trends variation rule and mutation of precipitation. Results showed that:（1）Annual precipitation in Tianjin urban area was mainly lower than the annual average 545.8 mm, but some precipitation data was far greater than the average value; the overall trend was increasing, but not significant; the extreme value ratio was 4.82, with uneven interannual distribution.（2）Results of 5-year moving average method showed 7 periods of decrease and 4 periods of increase for precipitation. Results of cumulative anomaly method showed 11 periods with excessive annual precipitation, totaling 41 years; 7 periods with insufficient precipitation, totaling 44 years. From 2019 to 2022, the cumulative anomaly of precipitation was on the rise, with excessive precipitation.（3）According to the M-K mutation test, 5 periods with a total of 68 years of precipitation showed a downward trend; since 1953, the overall trend was on the rise. 7 mutation points were obtained, and validated by the cumulative anomaly method. After removing pseudo points, the retained mutation points were 1948, 1979, 1984, and 2019.（4）According to wavelet analysis, there were four time-scales of periodic variation patterns for precipitation, including 5-6a, 12-13a, 32-34a, and 48-52a, and the most significant was 48-52a scale, with 51a as the first main period. It is speculated that in the following about 8 years after 2018, precipitation will still be relatively high. This achievement has reference value for the prevention of drought and flood disasters in Tianjin.

2025 Vol.32(5): 88–93    [Abstract] ( 28 )    [PDF 1234 KB ] ( 8 )

In view of the fact that the traditional ecological footprint model ignores the insufficient water resources occupied by water pollution and purification when considering the amount of water resources, and the water balance coefficient is calculated based on the global average level which can't reflect the actual situation of the study area, this paper uses the new calculation method of balance factor and water balance coefficient to improve the traditional ecological footprint model, analyzes the ecological footprint and ecological carrying capacity of water resources in Tianjin from 2012 to 2022, evaluates the sustainable use of water resources in Tianjin, and analyzes the ecological pressure on water resources in Tianjin. The results showed that from 2012 to 2022, the ecological footprint of water resources in Tianjin was 24.41 Mhm2, of which the ecological footprint of agricultural water accounted for the largest proportion, and the ecological footprint of water pollution showed a significant decrease. The ecological carrying capacity fluctuates year by year, and the interannual variation is greatly affected by the annual rainfall.

2025 Vol.32(5): 94–98    [Abstract] ( 31 )    [PDF 1276 KB ] ( 6 )

Taking optical isomerism as an example, BOPPPS teaching model, which contains Bridge-in, Objective, Pre- assessment, Participatiory Learning, Post-assessment and Summary, is adopted to design in this article. With Chaoxing Xuexitong App, blended teaching is carried out by pre-class, in-class, and after-class. Before class, the lecture is introduced by life phenomena and Thalidomide tragedy. The teacher uses the interactive question-chain teaching according to the pre-assessment, intersperses scientists' stories and agricultural applications. Students participate in class deeply with short plays and group discussions, consolidate and summarize what they have learned with post-test and mind mapping after class. The practice shows that the teaching mode motivates students' learning enthusiasm, and achieves the education effect, which provides ideas for the teaching reform of Organic Chemistry.

2025 Vol.32(5): 99–102    [Abstract] ( 33 )    [PDF 713 KB ] ( 14 )

Cognitive practice is an entry-level professional education that connects theory with practice and is an important practical education teaching link to guide students to understand and love their major. The aquatic animal medicine major is specially established and controlled by the nation. Compared with the traditional major of aquaculture, it focuses more on cultivating applied talents who master the knowledge and skills of aquatic animal clinical medicine. The author sorted out the teaching objectives and existing problems of the cognitive practice of aquatic animal medicine major, and put forward some suggestions for reform in order to provide reference for the cognitive practice of aquatic animal medicine major in the future.