A new isopropyl esterification method for quantitative profiling of short-chain fatty acids in human and cow milk by gas chromatograph-mass spectrometer.

Short-chain fatty acids (SCFAs) content in milk may have been underestimated due to the neglect of the esterified SCFAs content and the lack of an accurate detection method, especially for C1:0, C2:0, and C3:0 SCFAs. In this study, an accurate gas chromatography-mass spectrometry profiling method was established for 10 SCFAs. A 2-step esterification, including alkaline saponification (60°C for 30 min) and acid-catalyzed esterification (80°C for 150 min) in water/isopropyl/hexane (1:2:1, volume ratio), was found to be the most suitable for the quantification of esterified and nonesterified SCFAs analysis. The validation results demonstrate satisfactory linearity, sensitivity, matrix effects, precision, and accuracy. The recoveries of nonesterified and esterified SCFAs ranged from 82.78% to 112.49%, respectively. Human milk is distinguished from cow milk by its higher C1:0 and C2:0 content and lower C4:0 and C6:0 content. This method successfully accomplished qualitative and quantitative estimation of all 10 SCFAs in milk, including both nonesterified and esterified SCFAs. Furthermore, whether our method is applicable for the determination of SCFAs in serum, rumen fluid, and feces remains to be explored.

Impact of Processing Methods on the Distribution of Mineral Elements in Goat Milk Fractions.

Milk and dairy products are excellent sources of mineral elements, including Ca, P, Mg, Na, K and Zn. The purpose of this study was to determine the effect of non-thermal (homogenization) and thermal (heat treatment) treatments on the distribution of mineral elements in 4 milk fractions: fat, casein, whey protein, and aqueous phase. The study results revealed that the distribution of mineral elements (such as Mg and Fe) in fat fractions is extremely low, while significant mineral elements such as Ca, Zn, Fe, and Cu are mostly dispersed in casein fractions. For non-treated goat milk, Mo is the only element identified in the whey protein fraction, while K and Na are mostly found in the aqueous phase. Mineral element concentrations in fat (K, Zn, etc.) and casein fraction (Fe, Mo, etc.) increased dramatically after homogenization. Homogenization greatly decreased the concentration of mineral elements in the whey protein fraction (Ca, Na, etc.) and aqueous phase (Fe, Cu, etc.). After heat treatment, the element content in the fat fraction and casein fraction increased greatly when compared with raw milk, such as Cu and Mg in the fat fraction, Na and Cu in the whey protein fraction, the concentration of components such as Mg and Na in casein fraction increased considerably. On the other hand, after homogenization, Zn in the aqueous phase decreased substantially, whereas Fe increased significantly. Therefore, both homogenization and heat treatment have an effect on the mineral element distribution in goat milk fractions.

Effect of lactation on the distribution of mineral elements in goat milk.

The distribution of mineral elements in milk is crucial for their absorption and utilization, however, there has been limited attention given to the status of mineral elements in goat milk. In this study, goat milk was collected at 4 lactation periods (1-3, 90, 150, 240 d) and separated into 4 fractions (fat, casein, whey, and aqueous phase). The concentrations of Mg, Ca, Na, K, Zn, Fe, Cu, Mn, Co, Ni, Mo, and Cr in 4 fractions were analyzed using an inductively coupled plasma emission spectrometer. Our findings reveal that Ca, Zn, Fe, Cu, Mn, and Cr exhibit the highest levels in casein, while Mo demonstrates the highest content in whey. Additionally, Mg, Na, K, and Ni display the highest concentrations in the aqueous phase. Specifically, the contents of Ca, Cu and Fe in casein decrease from 1-3 to 150 d of lactation but increase from 150 to 240 d of lactation. Furthermore, the content of Mg in the aqueous phase decreases from 1-3 to 90 d of lactation but increases from 90 to 240 d of lactation. The content of Na and K in the aqueous phase decreases from 1-3 to 150 d of lactation. Notably, the content of Mo in whey increases from 1-3 to 150 d of lactation and decreases from 150 to 240 d. Our research contributes to the advancement of understanding the bioavailability of mineral elements in goat milk.

Bioactive Functions of Lipids in the Milk Fat Globule Membrane: A Comprehensive Review.

The milk fat globule membrane (MFGM) is a complex tri-layer membrane that wraps droplets of lipids in milk. In recent years, it has attracted widespread attention due to its excellent bioactive functions and nutritional value. MFGM contains a diverse array of bioactive lipids, including cholesterol, phospholipids, and sphingolipids, which play pivotal roles in mediating the bioactivity of the MFGM. We sequentially summarize the main lipid types in the MFGM in this comprehensive review and outline the characterization methods used to employ them. In this comprehensive review, we sequentially describe the types of major lipids found in the MFGM and outline the characterization methods employed to study them. Additionally, we compare the structural disparities among glycerophospholipids, sphingolipids, and gangliosides, while introducing the formation of lipid rafts facilitated by cholesterol. The focus of this review revolves around an extensive evaluation of the current research on lipid isolates from the MFGM, as well as products containing MFGM lipids, with respect to their impact on human health. Notably, we emphasize the clinical trials encompassing a large number of participants. The summarized bioactive functions of MFGM lipids encompass the regulation of human growth and development, influence on intestinal health, inhibition of cholesterol absorption, enhancement of exercise capacity, and anticancer effects. By offering a comprehensive overview, the aim of this review is to provide valuable insights into the diverse biologically active functions exhibited by lipids in the MFGM.

Updating the fatty acid profiles of retail bovine milk in China based on an improved GC-MS method: implications for nutrition.

The importance of food components to potential benefits and risks to human health is gradually being consumer awareness. Milk is an important part of the lipid content of the human diet, and there are few detailed reports on the fatty acid (FA) profiles of retail milk. In the study, we developed a gas chromatography-mass spectrometry (GC-MS) method to simultaneously determine 82 FAs, including 11 even-chain saturated FAs, 10 odd-chain saturated FAs, 9 branched-chain saturated FAs, 30 monounsaturated FAs, and 22 polyunsaturated FAs; this was applied to analyze samples (186 samples) of commercially available milk from 22 provinces throughout China and to evaluate the nutritional value of these samples based on FA-related indices. The results showed that the overall composition of milk FAs among the different regions was numerically similar, and minor FAs showed few differences. When considering the retail milk FA composition and dairy fat intake in China, regional variations have a limited impact on FA consumption. Moreover, milk accounts for approximately one-third and <10% of the maximum recommended intake of saturated FAs and trans-FAs in consumer diets, respectively. This study provides an updated report on the composition of FAs and the nutritional value of retail milk across China, which can serve as a reference for producers for future research on regulating milk FAs, for consumers to select milk, and for nutrition departments to formulate relevant nutritional guidance recommendations.

Response of mercury accumulation to anthropogenic pollution in the past 1000 years based on Lake Huguangyan sediments, Southern China.

A new 210Pb-dated record of Hg accumulation derived from a sediment core from a Hg-enriched area in Huguangyan Lake (HGY) in South China is presented. Based on synthetic analyses of multi-proxy records including chemical composition, total organic matter, and grain-size distribution in surface sediments and nearby soil samples, it is inferred that the influx of Hg into the lake is mainly a result of atmospheric deposition, with no or minor hydroclimate-induced lithogenic input from the catchment and limited adsorption effects of organic matter and clay. Significantly enhanced anthropogenic input of Hg started in the early 1900s. Since then, several anomalies of Hg accumulation have been the results of wars or intensified economic activities in China. HGY sediments provide a rare and reliable natural archive for detecting atmospheric Hg deposition, which is closely related to anthropogenic activities.

A 15,400-year record of natural and anthropogenic input of mercury (Hg) in a sub-alpine lacustrine sediment succession from the western Nanling Mountains, South China.

A 15400-year mercury (Hg) accumulation history was reconstructed from a lake sediment core collected from Daping Swamp in western Nanling Mountains, South China. Our results show that the natural input of Hg was deeply influenced by varying climatic conditions. Under wet and warm conditions, increased surface soil organic matter induced by improved vegetation conditions favor an increased input of surface soil-bound Hg to the lake, thus leading to higher Hg accumulation rate, and on the other hand, the direct atmospheric wet deposition of Hg into the lake would also be enhanced. In contrast, under relatively cold and dry conditions, it would display an inverse picture. The signal of anthropogenic influence possibly derived from regional Hg pollution likely started at ~ 3400 cal. years BP, roughly corresponding to the early stage of the Shang Dynasty in Chinese history. Four periods of increased anthropogenic Hg inputs appeared in ~ 3358-2170, ~ 2170-1730, ~ 1369-1043, and especially ~ 600-250 cal. years BP, corresponded to the Shang and Zhou, the Qin and Han, the Sui and Tang, and the Ming and Qing dynasties in China, respectively. A clearly weakened anthropogenic input occurred between~1750 and 1400 cal. years BP, coinciding with the Three Kingdoms to the Southern and Northern Dynasties. Our results revealed the history of the natural Hg accumulation since the Last Deglacial period, and the existence of regional atmospheric Hg induced from anthropogenic activity spanning the last ~ 3400 years.

Rescue fecal microbiota transplantation for antibiotic-associated diarrhea in critically ill patients.

BACKGROUND: Antibiotic-associated diarrhea (AAD) is a risk factor for exacerbating the outcome of critically ill patients. Dysbiosis induced by the exposure to antibiotics reveals the potential therapeutic role of fecal microbiota transplantation (FMT) in these patients. Herein, we aimed to evaluate the safety and potential benefit of rescue FMT for AAD in critically ill patients. METHODS: A series of critically ill patients with AAD received rescue FMT from Chinese fmtBank, from September 2015 to February 2019. Adverse events (AEs) and rescue FMT success which focused on the improvement of abdominal symptoms and post-ICU survival rate during a minimum of 12 weeks follow-up were assessed. RESULTS: Twenty critically ill patients with AAD underwent rescue FMT, and 18 of them were included for analysis. The mean of Acute Physiology and Chronic Health Evaluation (APACHE) II scores at intensive care unit (ICU) admission was 21.7 ± 8.3 (range 11-37). Thirteen patients received FMT through nasojejunal tube, four through gastroscopy, and one through enema. Patients were treated with four (4.2 ± 2.1, range 2-9) types of antibiotics before and during the onset of AAD. 38.9% (7/18) of patients had FMT-related AEs during follow-up, including increased diarrhea frequency, abdominal pain, increased serum amylase, and fever. Eight deaths unrelated to FMT occurred during follow-up. One hundred percent (2/2) of abdominal pain, 86.7% (13/15) of diarrhea, 69.2% (9/13) of abdominal distention, and 50% (1/2) of hematochezia were improved after FMT. 44.4% (8/18) of patients recovered from abdominal symptoms without recurrence and survived for a minimum of 12 weeks after being discharged from ICU. CONCLUSION: In this case series studying the use of FMT in critically ill patients with AAD, good clinical outcomes without infectious complications were observed. These findings could potentially encourage researchers to set up new clinical trials that will provide more insight into the potential benefit and safety of the procedure in the ICU. TRIAL REGISTRATION: ClinicalTrials.gov, Number NCT03895593 . Registered 29 March 2019 (retrospectively registered).