Enhancing the antioxidant capacity and quality attributes of fermented goat milk through the synergistic action of Limosilactobacillus fermentum WXZ 2-1 with a starter culture.

This study evaluated 75 strains of lactic acid bacteria (LAB) isolated from traditional dairy products in western China for their probiotic properties. Among them, Limosilactobacillus fermentum WXZ 2-1, Lactiplantibacillus plantarum TXZ 2-35, Companilactobacillus crustorum QHS 9, and Companilactobacillus crustorum QHS 10 demonstrated potential probiotic characteristics. The antioxidant capacity of these 4 strains was assessed, revealing that L. fermentum WXZ 2-1 exhibited the highest antioxidant capacity. Furthermore, when cocultured with Streptococcus salivarius ssp. thermophilus and Lactobacillus delbrueckii ssp. bulgaricus, L. fermentum WXZ 2-1 demonstrated a synergistic effect in growth medium and goat milk. To explore its effect on goat milk fermentation, different amounts of L. fermentum WXZ 2-1 were added to goat milk, and its physicochemical properties, antioxidant activity, flavor substances, and metabolomics were analyzed. The study found that the incorporation of L. fermentum WXZ 2-1 in goat milk fermentation significantly improved the texture characteristics, antioxidant capacity, and flavor of fermented goat milk. These findings highlight the potential of L. fermentum WXZ 2-1 as a valuable probiotic strain for enhancing the functionality and desirability of fermented goat milk, contributing to the development of novel functional foods with improved health benefits and enhanced quality attributes.

Robust microfluidic construction of konjac glucomannan-based micro-films for active food packaging.

The objective of this study was to develop a novel active food packaging with high performance by using natural active compound. Here, a facile and green strategy was employed to construct the konjac glucomannan/polylactic acid/trans-cinnamic acid micro-films (KPTMF) via microfluidic spinning technology (MST). MST, a mild preparation approach, could remain the activities of natural compound during processing. Konjac glucomannan could drive the release of trans-cinnamic by using its hydrophilicity under our careful design. The results of fourier-transform infrared spectra and infrared images revealed that konjac glucomannan, polylactic acid, and trans-cinnamic acid had good compatibility through hydrogen bonds in the micro-films, which was consistent with the X-ray diffraction results. Also, the good swelling degree (81.36 ±â€¯5.79%) of KPTMF could promote the release of trans-cinnamic. Besides, the KPTMF had excellent mechanical properties (Tensile strength: 14.09 ±â€¯2.97 MPa, Elongation at break: 3.12 ±â€¯0.57%), thermal stabilities and hydrophobicity (Water vapor permeability: 4.81 × 10-6 g/(m·h·kPa), Water contact angle: 99.2°). The obtained micro-films with large specific surface areas exhibited great antibacterial activities against Staphylococcus aureus and Escherichia coli, which suggested the potential applications in active food packaging.

Physicochemical properties of degraded konjac glucomannan prepared by laser assisted with hydrogen peroxide.

The exploration of methods for degrading konjac glucomannan (KGM) is of great significant and technological interest. Here, laser at the power of 10 W was employed to degrade KGM. The laser degraded konjac glucomannan (LDK) was analyzed by viscosity, Rheology, Differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) spectroscopy and laser light scatter (LLS). The viscosity of the LDK decreased from 8.38 Pa·s to 2.26 Pa·s and the average molecular weight (Mw) decreased from 7.6 × 105 Da to 5.7 × 105 Da with a polydispersity index (PDI) of 1.166. FT-IR spectra and IR images of the LDK indicated that the breakage of glucosidic bonds occurred during laser irradiation. DSC results indicated that the thermal stability of KGM has improved slightly after degradation. In addition, the determination of 1,1-diphenyl-2-picrylhrazyl (DPPH) radical scavenging activity suggested that the antioxidant activity of the LDK improved versus KGM. This stratagem provides a new pathway for efficiently degrading KGM.

[Transformation of Cu forms in Cynodon dactylon rhizosphere soil of copper tailings yard].

The study on the Cu forms in Cynodon dactylon rhizosphere soil of copper tailings yard in Tongling City, Anhui Province showed that among the test Cu forms, the amount of residual form occupied the majority, while that of exchangeable form was relatively low. Compared with non-rhizosphere soil, rhizosphere soil had a higher organic matter content but a lower pH. With the growth of C. dactylon, the contents of organically combined and exchangeable Cu in rhizosphere soil increased by 7.89% and 5%, respectively, while those of carbonate-combined and Fe-Mn oxides-combined Cu decreased. The growth of C. dactylon accelerated the transformation of Cu forms in rhizosphere soil, and decreased the rhizosphere soil Cu content through its absorption.

[Impact of Cu and Zn pollution on rape growth and soil enzyme activity].

A pot experiment was conducted to study the impact of Cu and Zn pollution on soil enzyme activities and rape seedlings growth. The results showed that Cu had a stronger inhibitory effect than Zn on soil urease activity, while Zn had more obvious impact on soil calatase activity. The damage on the growth and dry mass of rape was more serious under Cu than under Zn pollution. The inhibition of rape seedlings growth was mainly due to the inhibition of root growth and its material accumulation. Factor analysis indicated that root dry mass was more sensitive than other indices, which could be adopted to monitor soil Cu and Zn pollution.

[Coercion and damage of Cu pollution on Artemisia lavandulaefolia growth].

By the method of solution culture, this paper studied the coercion and damage of Cu pollution on the growth of Artemisia lavandulaefolia. The Cu concentration was set as 2.5, 5, 10, 20 and 40 mg x L(-1), experimental duration was 14 days, and the growth and physiological indices of plants were tested. The results showed that the growth of A. lavandulaefolia was stimulated at low Cu concentration (2.5 mg x L(-1)), while inhibited at higher Cu concentrations (5 to approximately 40 mg x L(-1)). There was a significant negative correlation between each growth index and Cu concentration, and pigments contents had the similar trend. The sensibility of various photosynthetic pigments to Cu was in the order of chlorophyll a > chlorophyll a + b > chlorophyll b > carotenoid. Cell membrane permeability, O2 generation rate, and MDA content decreased slightly at 2.5 mg Cu x L(- 1) and then increased with increasing Cu concentration. The activities of POD, SOD and CAT increased first but decreased then with the increasing Cu concentration, and the endurance index of root showed the same trend, being > 0.5 at the Cu concentration less than 20 mg x L(-1) while decreased to 0.36 at 40 mg Cu x L(-1).

[Enzyme activities in Paeonia ostii rhizosphere and non-rhizosphere soil of Tongling copper mining].

The study on the calatase, polyphenol-oxidase, invertase, urease and phosphatase activities in Paeonia ostii rhizosphere and non-rhizosphere soil of Tongling copper mining showed that all test enzyme activities were higher in rhizosphere than in non-rhizosphere soil. Soil calatase, urease and phosphatase were sensitive to heavy metals pollution, and their activities could be used as the indicators of heavy metals' joint pollution. The effects of rhizosphere environment on the soil enzyme activities were in the sequence of phosphatase > urease > calatase > invertase > polyphenol-oxidase, and the affecting rate was 131.562%, 92.492%, 87.557%, 59.673% and 34.076%, respectively. The test enzyme activities were negatively correlated with soil heavy metals pollution, and the correlation coefficients were all higher than -0.898, suggesting the inhibitory effects of heavy metals' joint pollution on soil enzyme activities. P. ostii could effectively improve soil environment, and thus, enhance the activities of soil enzymes.

[Effects of Cd on rape growth and antioxidant enzyme system].

The study with pot experiment showed that the fresh weights of rape plant and leaf decreased with increasing Cd concentration, and the decrease of leaf fresh weight resulted in the decrease of whole plant fresh weight. The permeability of cell membrane and the content of MDA increased with increasing Cd concentration. When the concentration of Cd was 20 mg x kg(-1), compared with the control, cell membrane permeability and MDA content were increased by 29.68% and 15.19% respectively, and there was a significant correlation between these two indices. When the Cd concentration was 5 mg x kg(-1), the contents of chlorophyll a, b and a + b reached their peaks, and were 23.97%, 33.63% and 26.45% higher than the control, respectively. Cd stress had no significant effect on carotenoid content. The sensibility of the pigments to Cd stress was chlorophyll b> chlorophyll a> chlorophyll a + b> carotenoid, and that of protective enzymes was POD>CAT>SOD. The IC50 of test physiological indices suggested that rape could only grow well on the soil with < 5 mg x kg(-1) Cd.

Separate and combined effects of Cu and Cd on seedling growth and active oxygen metabolism system of Trifolium repens L.

Pot-culture experiments were used to examine the individual and combined effects of Cu and Cd pollutants on Trifolium repens L. seedlings, both on their growth and their active oxygen metabolism system, mainly superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activities. The results showed that the negative action took place at low concentrations of Cu (less than 500 ppm) and Cd (less than 0.5 ppm), which had no obvious effects on the seedlings' growth. However, as the concentrations of Cu and Cd increased (500-3000 ppm and 0.5-50 ppm respectively), synergistic activities was observed, showing obvious negative effects (P less than 0.05). Compared with the control samples, the seedlings affected by Cu and Cd pollutants were shorter and smaller, their fresh/dry weight and content of soluble protein decreased drastically, their leaf electric conductivity increased, and the contents of their leaf pigments decreased. Chlorophyll a was more sensitive than chlorophyll b to Cu and Cd pollutants, and chlorophyll b was more sensitive than carotenoid. It was also shown that the active oxygen metabolism of T. repens seedlings was destroyed by high amounts of Cu and Cd, the balance of the anti-oxidase system was broken, and the CAT and SOD activities noticeably decreased while POD activity evidently increased. Cd had a more noticeable effect on seedling growth than Cu.

[Physiological metabolism and protective enzyme activity of Equisetum ramosissimum under Cu stress].

The study with pot culture experiment showed that Equisetum ramosissirmunm did not appear obvious poisoning symptoms when treated with low concentration Cu (500 mg x kg(-1)), while serious injuries were found when treated with high concentration Cu (1000 to approximately 3000 mg x kg(-1)), which reflected in the severe damage of cell membrane and cytoarchitecture as well as the structure and function of main organelles, and the significant decrease of the contents of leaf chlorophyll a and b and stem soluble monosaccharose. The cell membrane osmolarity and the average MDA content of the plant exposed to heavy copper pollution was 1 to approximately 2 and 1 to approximately 3 times greater than the control, respectively. It could be concluded that high concentration Cu disturbed the physiological metabolism, and critically threatened the normal growth of E. ramosissimum. The activities of protective enzyme, especially of SOD and POD, were enhanced with increasing Cu concentration, and had a positive correlation with Cu concentration (rPOD = 0.978, rSOD = 0.926, P < 0.05).

[Effects of different concentration copper on pigment content and antioxidase system of Spirodela polyrrhiza and Lemna minor].

The study with water culture showed that when treated with 0.056 mg Cu x L(-1), the chlorophyll a, b and (a + b) contents in Spirodela polyrrhiza and Lemna minor were increased by 11%, 46% and 22%, and 8%, 15% and 11%, while under 0.15 to approximately 5.6 mg Cu x L(-1) the contents were decreased by 63%, 62% and 63%, and 46%, 45% and 45%, respectively, compared with no copper added. The malondialdehyde (MDA) content in S. polyrrhiza was 2.75 times higher than that in L. minor averagely. The superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activities in both S. polyrrhiza and L. minor all increased first, but decreased then with increasing copper concentration. For S. polyrrhiza, the activities of test enzymes were the highest at 0.18 mg Cu-L(-1), but for L. minor, only when the Cu concentrations were up to 0.56, 1.0 and 1.0 mg x L(-1), the activities of SOD, CAT and POD got to their peak values, respectively. It was concluded that higher concentrations of copper caused more damage to S. polyrrhiza than to L. minor, and the antioxidase system of the former was much more sensitive to the copper stress than that of the latter.

Study of the tolerance of Hippochaete ramosissimum to Cu stress.

We investigated the tolerance of Hippochaete ramosissimum and the changes in physiological metabolism following exposure to copper using pot experiments and analyzing plant physiology and biochemistry. The results showed that Cu tolerance in Hippochaete ramosissimum varied significantly between different populations; the tolerance of plants living in Cu polluted areas for extended periods of time exceeded that of plants living in unpolluted areas. SOD and POD activities in highly Cu tolerant plants increased noticeably following exposure to Cu. This indicates that maintaining and increasing the two kinds of protective enzyme activities are the primary foundations of plant tolerance. However, no change in CAT activity was demonstrated following Cu exposure. In summary, there existed considerable differences in physiological metabolism between different populationsof Hippochaete ramosissimum following exposure to Cu.

[Responses of Conyza canadensis to different concentrations of copper in soil].

Through pot experiment and physiological-biochemical analysis, the study showed that the electric conductivities of Conyza canadensis collected from heavy Cu pollution (I), light Cu pollution (II) and control (III) sites were enhanced, while the chlorophyll (a + b) contents were reduced with increasing Cu concentration. The protein and proline contents in I were increased at first and then reduced, but those in II and III were reduced with increasing Cu concentration. The activities of SOD, POD and CAT were intensified under Cu stresses. When the Cu concentration was 1 200 mg x kg(-1), their activities in I, II and III were increased 194.1%, 206.2% and 118.6%, 170.1%, 182.9% and 111.3%, and 115.1%, 155.4% and 107.3%, respectively, in comparing with the control, which illustrated that the tolerance of Conyza canadensis was in order of heavy Cu pollution site > light Cu pollution site > control site, and the three ecotypes showed distinct differences in tolerance.

[Heavy metals pollution of Paeonia ostii land at copper-tailings reservoir of Tongling city: a preliminary study].

The study on the soil and Paeonia ostii Cu, Cd, Pb and Zn at the copper-tailings reservoir of Tongling City, Anhui Province showed that the forms and contents of test heavy metals were differed in Paeonia ostii-planted and control soils. The Cu and Cd contents in control soil were 4.36-14.43 and 3.67-3.86 times of the 2nd national standard for soil environmental quality, respectively, and the composite pollution index of the heavy metals in Paeonia ostii-planted soil was up to 5.607. The heavy metals content in Paeonia ostii leaf and root-stem was in order of Cu>Zn>Pb>Cd, and that in Paeonia ostii stem and root- peel was Zn>Cu>Pb>Cd. The comparison of the heavy metals contents in Paeonia ostii with the criterion about herbal medicine showed that the Cu content in Paeonia ostii was 1.43-2.53 times of the criterion, and the Cd content was 1.17-3.17 times of the criterion.

[Effects of Alternaria azukiae on physiological metabolism and active oxygen-eliminating enzyme activities of Trifolium repens].

A pot experiment was installed to study the effects of Alternaria azukiae inoculation on the cell membrane permeability, pigment and MDA contents, and activities of SOD, POD and CAT of Trifolium repens. The results showed that A. azukiae infection made T. repens leaf tissue increase its cell membrane permeability, electric conductivity, over-oxidation and MDA content, but decrease its pigment content. The electric conductivity and MDA content were positively related with infection time, whereas the pigment content was negatively related with it. Due to the stimulation by A. azukiae, the over-oxidation of cell membrane was intensified, which resulted in a large amount of active oxygen accumulated and beyond the defense ability, the active oxygen metabolism system was destroyed, and the balance of protective enzyme system was broken. After 12 days of A. azukiae inoculation, the activities of SOD and CAT decreased by 55.2% and 37.8%, respectively, while the POD activity increased by 1.6 times.

[Cu and Zn pollution and soil enzyme activities in sewage irrigation area near smeltery].

This paper studied the Cu and Zn status in soil and rice plant as well as the soil enzyme activities in the sewage irrigation area near a smeltery. The results showed that the soils near the smeltery were polluted. The soil total and extractable Cu contents at the distance of 100 m were 182.45 and 81.91 mg x kg(-1), respectively, 9.3 and 34 times higher than the control. The Cu concentration in different parts of rice was in order of root > leaf and stem > grain, while the Zn concentration was in order of leaf and stem > root > grain. Zn was more mobile than Cu which was likely to accumulate in rice root. It was considered that root could act as a barrier which retarded the upwards transport of Cu and protected the above ground parts of rice from toxication. The Cu contents of rice stem and leaf had a significant correlation with soil Cu contents in the sewage irrigation area. Among the three test enzymes, urease was the most sensitive one to Cu, and its activity had a significant correlation with soil Cu content. Therefore, it is feasible to use soil urease activity as an indicator of soil Cu pollution in sewage irrigation area near the smeltery.

[Nitrite content of common vegetables in Wuhu City].

Laboratory analysis was carried out to study the nitrite content and its affecting factors of 10 common vegetables in terminal markets of Wuhu City. The results showed that the nitrite content of root or stem- and fruit vegetables was lower than the national standard, but that of leaf vegetables exceeded the standard seriously. The nitrite in vegetables increased significantly with storage time. Stored under room temperature, the test vegetables had 1-2 times higher nitrite content at the fourth day than at the first day, but storage under low temperature, i. e., in refrigerator, could hinder the increase of nitrite content in vegetables, and the daily increase was only 1/2-1/6 times of that under room temperature. Abluent could eliminate nitrite effectively, whose efficiency was 1-5 times higher than that of tap water.

[Effects of copper pollution on Trifolium repens growth and soil enzyme activities].

The study with pot experiment showed that with increasing Cu concentration, soil urease, invertase, catalase and polyphenol oxidase activities decreased gradually. There was a significant correlation between Cu concentration and soil enzyme activities, with the correlated degree followed the order of invertase > polyphenol oxidase > urease > catalase. Under a fixed Cu concentration, soil enzyme activities changed with time, and the changes were different between high and low Cu concentrations, being increased slightly under low Cu concentration (< 500 mg x kg(-1)), but decreased gradually as Cu concentration increased (500-3000 mg x kg(-1)). Statistical analysis indicated that within the range of test Cu concentrations, the activities of test soil enzymes were significantly different among different Cu concentration (P < 0.01), which was accorded with the seedlings growth status. Soil pH was decreased, while electric conductivity was increased with increasing Cu concentration (500-3000 mg x kg(-1)), but they were increased with time under a fixed Cu concentration, with significant difference among different Cu concentration (P < 0.01) . Soil pH and electric conductivity were highly related to soil enzyme activities, with the order of polyphenol oxidase > invertase > catalase > urease. The test soil enzyme activities could be used as the indices of soil environment quality.

[Chemical forms of heavy metals in the soils and plants of copper tailings yard].

The study on the chemical forms of heavy metals in the soils and plants at the copper tailings yard in Tongling City indicated that the soils were extremely poor, with organic mater content being 2.6-5.8 g x kg(-1), only 1/15 of the control, while their Cu, Cd, Pb and Zn contents were higher than the control, with Cu 809.30-1395.54 mg x kg(-1) and Cd 3.25-6.35 mg x kg(-1), as 30-60 times as those of the control. The heavy metals contents in Zoysia japonica and Trifolium pratense had a significantly positive correlation with the contents of their exchangeable and organic forms in soils, a significantly or very significantly negative correlation with the forms of Fe-Mn oxides and carbonate, and no correlation with residual form. The main forms of Cu, Zn and Pb in Z. japonica and T. pratense were HAC-and HCl-extractable, and residual. The NaCl-extractable Zn content in the roots, stems and leaves of Z. japonica and T. pratense occupied a higher proportion, while NaCl-extractable Cd was the main form of Cd in both of the plants, not only in their roots but also in their leaves.

[Cd, Cu, Zn and Pb contents and forms in soils and rapeseeds around Wuhu Plant].

The study showed that around Wuhu Plant, soil Cd, Zn and Pb mainly existed in Fe-Mn oxide form, and Cu in residual form, with the percentage of 31.81%, 39.83%, 53.79%, and 46.24%, respectively. Soil exchangeable Cd and Pb had a higher proportion (23.47% and 16.32%) than soil exchangeable Cu and Zn (3.14% and 0.54%). The correlations between soil heavy metals and their forms, as well as their transformation to available form were different. Different heavy metals had different accumulation trends in rapeseed and its hull. Cu easily accumulated in hull, while Cd, Zn and Pb had a higher accumulation in seed. The accumulation rate of heavy metals in rapeseed and hull was also different, being the highest for Cd. There was a significantly negative correlation (P < 0.05) between the accumulation rate of heavy metals and their contents in soil. In rapeseed, Cd, Cu and Pb were mainly in sodium hydroxide form, with the percentage of 32.50%, 22.94% and 34.69%, respectively, while Zn was mainly in EDTA form, with a percentage of 45.97. The existed forms of heavy metals in rapeseed probably affected their toxicity, but the toxicity to human food could not be inferred from this research, and needed to be studied further. There was a weak relation between heavy metals contents and their existed forms in rapeseed.