Decreased nitrogen deposition in Beijing over the recent decade and its implications.

Atmospheric reactive nitrogen (Nr) deposition has been modified significantly by human activities such as agriculture and fossil fuel combustion. Understanding the changes in Nr deposition is essential for maintaining the functionality and sustainability of ecosystems. Taking Beijing as a case study, we report long-term measurements of wet Nr deposition from 1999 to 2022 and dry Nr deposition from 2010 to 2022 and their relationship with China's air pollution control. Total Nr deposition to Beijing decreased by 34 % during 2010-2022, mainly caused by a decrease in dry N deposition by 54.27 %, from 47.86 kg N ha-1 yr-1 in 2010-2014 to 21.89 kg N ha-1 yr-1 in 2018-2022; reduced and oxidized N in dry deposition decreased by 29.93 % and 72.05 %, respectively. This was a result of the "Action Plan for Prevention and Control of Air Pollution (APCP)" and the implementation of the "Zero Growth in Fertilizer Use by 2020" in 2015. Our ground-based measurements provide evidence to support recent achievements in air pollution control and a reference and guidance for other regions of China and other countries for abating Nr pollution.

Comparison of screening indicators for different types of thalassemia carriers in Hunan Province.

Background: Carrier screening is the most effective method to block the occurrence of thalassemia. However, due to differences in race and genotype, MCV, MCH, HbA2 and other indicators are far from each other. The purpose of this study is to evaluate the common screening indicators of a, b and ab-compound thalassemia carriers in Hunan Province, and try to use the relevant formulas in the existing literature to predict and distinguish different types of thalassemia carriers. Methods: Receiver operating characteristic curve (ROC curve) combined with Youden index was utilized to analyze results of blood routine examination, hemoglobin electrophoresis, and literature-related formulas for 1111 a-thalassemia carriers, 464 b-thalassemia carriers and 24 ab-thalassemia carriers.

The effect of lactose and its isomerization product lactulose on functional and structural properties of glycated casein.

Lactulose is an isomer of lactose, formed under thermal processing of milk. Alkaline conditions favor the isomerization of lactose. As reducing sugar, lactose and lactulose could participate in the Maillard reaction and cause protein glycation in milk products. In this study, the influence of lactose and lactulose on the functional and structural properties of glycated casein was investigated. The results demonstrated that compared with lactose, lactulose led to severer changes in molecular weight, more disordered spatial structure and decrease of tryptophan fluorescence intensity of casein. Besides, the glycation degree and advanced glycation end products (AGEs) results suggested that lactulose exhibited stronger glycation ability than lactose due to the higher proportion of open chain in solution. Furthermore, higher glycation degree induced by lactulose resulted in lower solubility, surface hydrophobicity, digestibility and emulsifying capacity of casein-glycoconjugates compared with lactose. The results of this study are essential for tracking the effects of harmful Maillard reaction products on the quality of milk and dairy products.

The effect of B-type procyanidin on free radical and metal ion induced ß-lactoglobulin glyco-oxidation via mass spectrometry and interaction analysis.

Procyanidin is a group of dietary flavonoids abundant in berry fruits. In this study, the effects and underlying mechanisms of B type procyanidin (PC) on free radical and metal ion (H2O2, AAPH and Fe3+) induced milk protein ß-lactoglobulin (BLG) glyco-oxidation were investigated. The results indicated that PC protected BLG structure changes from cross-link and aggregation induced by free radicals and metal ion. Additionally, it effectively inhibited BLG oxidation by reducing approximately 21%-30% carbonyls and 15%-61% schiff base crosslink formation. Also, PC suppressed BLG glycation by inhibiting 48-70% advanced glycation end-products (AGEs) and reduced the accumulation of intermediate product methylglyoxal (MGO). The corresponding mechanisms were elucidated that PC exhibited great free radical scavenging and metal chelating properties; PC had non-covalent bind with the amino acid residues (preferably lysine and arginine) of BLG and blocked them from glycation; PC interrupted BLG glycation by forming procyanidin-MGO conjugates. Therefore, B type procyanidin was an effective glyco-oxidation inhibitor in milk products.

Spectroscopic analysis of the effect of glycation on casein structure and aggregation and its dependence on lactose concentration.

In order to study the effect of glycation on the molecular structure of casein (CN), three groups of simulated milk powders with different lactose (Lac) contents, CN:Lac = 1:1.5, 1:2, and 1:2.5 (m:m), were constructed. The glycation level and the structural changes of CN were analyzed by multiple spectra. The results showed that the interaction between Lac and CN molecules was based on the dynamic quenching of collision. A higher quenching constant, KSV, means that the 1:1.5 group showed more distinct glycation levels. In addition, CN glycation reduced the aggregation of casein micelles caused by heating treatment and repaired the structural damage of CN induced during the heating process. There was no positive correlation found between Lac content and protein glycation; thus, decreasing the Lac content of milk powder is not likely to be an effective method to prolong storage stability.

Lactose crystallization and Maillard reaction in simulated milk powder based on the change in water activity.

Maillard reaction (MR) and lactose crystallization (LC) are important reactions in the storage of milk powder. In this study, three models with different proteins based on skimmed milk powder were established to investigate the relationship between MR and LC at different water activities (aw ). Moisture sorption isotherm, glass transition temperature (Tg ), and glycation products were evaluated, and the protein structure and lactose crystallinity were determined. The results indicated that MR product content, browning, and LC subsequently enhanced with the increase in aw . The Tg value dropped lower than 0 at aw 0.43 in whey protein isolate-lactose (WP-Lac) model and at aw 0.54 in casein-whey protein isolate-lactose (CN-WP-Lac) model and casein-lactose (CN-Lac) model. The crystallinity of α-lactose monohydrate and anhydrous ß-lactose in WP-Lac model was more significant than CN-WP-Lac and CN-Lac models (p < 0.05). The molecular band of whey protein gradually blurred in the Sodium dodecyl-sulfate polyacrylamide gel electrophoresis image, and the content of α-helix of WP-Lac model increased by 45.15% from aw 0.33 to 0.53 (p < 0.05), while that of CN-WP-Lac model increased by only 3.95% (p < 0.05). With the increase in aw , WP-Lac model formed more browning and crystallization products than CN-WP-Lac model, indicating that the presence of micelle macromolecules and the interaction between casein and whey proteins limited the browning and crystallization in CN-WP-Lac model. Practical Application Maillard reaction and lactose crystallization are important reactions in the storage of milk powder, and the result will provide theoretical guidance for the development of milk powder in the food industry.

Smart Supervision for Food Safety in Food Service Establishments in China: Challenges and Solutions.

ABSTRACT: Foodborne diseases are a burden in countries worldwide. Several countries have successfully implemented policies that establish innovative systems for the inspection and grading of food service establishments (FSEs), which have greatly contributed to a reduction in foodborne diseases. China's government has also responded by developing policies to protect consumers' food safety, including the routine inspection policy and the risk-based grading policy. However, implementation of both policies has been poor to date. The aim of this study was to identify regulatory challenges and design a smart supervision solution. The results of a national survey showed that the major barriers to policy implementation were a heavy individual workload, the high turnover rate of FSEs, lack of a monitoring and evaluation system, lack of social support, low development of food safety training programs in FSEs, and a lack of financing. A smart supervision solution to these challenges was designed based on mobile Internet and two-dimensional (2D) barcode technology. A pilot application in Jilin province assisted local supervisors in carrying out regulatory work on FSEs, which proved the feasibility of smart supervision. This study can be used as an example for food safety supervision in other regions, and it can assist other governments that wish to implement similar policies to ensure food safety in their countries.