Camel milk modulates the gut microbiota and has anti-inflammatory effects in a mouse model of colitis

Camel milk is a nutritionally rich food that shows anti-inflammatory, immune regulation, and gut microbiota maintenance properties. However, the relationship between camel milk and the intestinal microbiota during colitis is unclear. Herein, we evaluated the protective effect of camel milk in mice with colitis induced using dextran sodium sulfate. Our results showed that camel milk can prevent body weight loss and colon shortening, reduce the disease activity index, and attenuate colon tissue damage. Additionally, camel milk could reduce the overexpression of inflammatory factors, inhibit the apoptosis of intestinal epithelial cells, and promote the expression of claudin-1, occludin, and zonula occludens-1 proteins. Moreover, camel milk effectively regulated intestinal microbiota in mice with colitis by increasing the gut microbiota diversity, increasing the abundance of beneficial bacteria (such as g_norank_f_Muribaculaceae, and Lachnospiraceae_NK4A136_group), and reducing the number of harmful bacteria (Bacteroides, Escherichia-Shigella). In addition, camel milk increased the levels of intestinal short-chain fatty acids. The results of the present study demonstrated that via regulating the intestinal microbiota, maintaining intestinal barrier function, and inhibiting proinflammatory cytokines, camel milk can ameliorate dextran sodium sulfate–induced colitis.     

N-Acetyl-B-D-glucosaminidase activity and somatic cells in goat milk

N-Acetyl-B-D-glucosaminidase activity, somatic cell count, and udder infection status were determined in milk of nine Saanen goats. Plasma enzyme activity was also measured. Individual half udder milk samples were taken for 12 d over a 3-wk period and animals were bled weekly. Three of the 18 udder halves were infected with coagulase-negative staphylococci over all 12 sampling d. The N-acetyl-B-D-glucosaminidase and somatic cells in milk were significantly elevated in samples where minor pathogens were isolated. Plasma enzyme was variable among goats but not within goats or across weeks. Greater daily variation was seen in somatic cell count as compared to milk enzyme activity. Correlation between milk N-acetyl-B-D-glucosaminidase and somatic cell count was .54.     

Factors affecting growth factor activity in goat milk

Growth factors that are present in goat milk may be responsible for its beneficial effects on the digestive system as described in ancient Chinese medical texts. To develop a nutraceutical product rich in growth factors for promoting gastrointestinal health, it is essential to collect milk with consistently high growth factor activity. Therefore, we investigated the factors affecting growth factor activity in goat milk. Among the 5 breeds of dairy goats tested, milk from Nubian goats had the highest growth factor activity. Tight-junction leakage induced by a 24-h milking interval did not increase growth factor activity in the milk. Milk collected from pregnant does had a significantly higher growth factor activity than milk collected postpartum. Growth factor activity decreased during the first 8 wk of lactation, fluctuated thereafter, and then increased dramatically after natural mating. During wk 1 to 8, growth factor activity was inversely correlated with milk yield and week of lactation. No correlation was observed during wk 9 to 29. After natural mating of the goats, the growth factor activity in the milk correlated significantly with somatic cell count and conductivity (a measure of membrane permeability), and correlated inversely with milk yield. Based on the above data, goat milk with higher growth factor activity could be selectively collected from Nubian pregnant does.     

羊奶膻味脂肪酸代谢调控研究

山羊奶是一种营养完全的食品,含有能促进人类生长发育以及维持健康的必需营养成分,它所含各种营养成分的比例,大体适合人类的生理需要。发展山羊奶业不仅是对中国奶业数量上的补充,而且在品质上,与牛奶相比更具潜力。但是由于羊奶具有膻味,因此羊奶及其制品的市场占有率很低。研究证明羊奶中短、中链脂肪酸是造成膻味的主要原因。文章对近年来羊奶膻味与脂肪酸代谢及基因调控等的研究状况进行了综述。     

圣女果百合搅拌型羊酸奶工艺技术研究

利用鲜羊乳为基料发酵,在传统酸奶发酵剂基础上添加双歧杆菌作为混合发酵剂,添加圣女果、百合混合浆液参与后发酵,通过单因素、正交实验确定搅拌型圣女果百合羊酸奶的优化配方。结果表明:该酸奶最优配方为圣女果和百合的混合浆10%(辅料混合比例为6∶4),蔗糖添加量9%,接种量4%,稳定剂添加量3‰,所得产品富含益生菌,营养丰富,是一种新型羊酸乳制品。     

酮香型羊酸奶的研制及与牛酸奶风味物质的比较

以羊奶粉为主要原料,选用丁二酮乳链球菌、嗜热链球菌和保加利亚乳杆菌相配合的发酵剂研制山羊酸奶,酮香型羊酸奶各因素的最佳配比为丁二酮乳链球菌、嗜热链球菌及保加利亚乳杆菌配比为1∶1∶2,菌种添加量为4%,加糖量为8%,发酵温度为40℃。采用SPME-GC-MS技术,对羊酸奶中风味物质进行分析,检测出19种主要风味物质,以酮类、醇类、呋喃类和羧酸类为主,主要特征风味物质是丁二酮、乙酸、甲酸甲酯、辛酸、丁醛、棕榈酸、苹果酸、DL-丙氨酸、呋喃甲醇、庚醇、邻苯二甲酸二乙酯。     

发酵羊乳中乳酸菌低产粘菌株的筛选

对从商业乳酸菌发酵剂分离纯化的11株保加利亚乳杆菌和11株嗜热链球菌在发酵羊乳中的粘度进行了研究。结果表明,保加利亚乳杆菌L.b-124菌株和L.b-346菌株、嗜热链球菌S.t-222菌株和S.t-346菌株具有较低的产粘能力,凝乳时间也较短;将L.b-346菌株与S.t-346菌株按杆菌和球菌1:1比例混合后在43℃下发酵羊乳时,可获得较低的发酵粘度。     

Microbiota dynamics and lactic acid bacteria biodiversity in raw goat milk cheeses

Raw goat milk collected at 11 Andalusian dairy plants was used to individually manufacture cheeses without starter culture addition. Microbial groups were monitored during ripening for 60 days. A total of 1442 lactic acid bacteria (LAB) isolates randomly chosen were identified by molecular methods. Counts of mesophilic LAB exceeded 9 log cfu g⁻¹ on day 1 and decreased 0.5 log units during ripening whereas counts of lactobacilli and leuconostocs increased and those of enterococci remained constant. Thirty-three LAB species belonging to eight different genera were isolated, with higher biodiversity on day 1 (26 species) than on day 60 (20 species). Structural genes coding for nisin, lacticin 481, lactococcin B, six plantaricins and five enterocins were detected in LAB isolates. The information obtained on the technological properties of selected isolates may be useful in developing specific starters for goat milk cheeses, capable of maintaining their distinctive sensory characteristics.     

Evaluation of the allergenicity of goat milk, cow milk, and their lactosera in a guinea pig model

The object of this study was to determine the allergenicity of goat milk (GM) and cow milk (CM) and that of their respective lactosera (GML and CML), by in vivo and in vitro assays. Two systemic tests for anaphylaxis were carried out in guinea pigs, the animals being sensitized orally with the 2 types of milk and lactosera. Sera were taken from the orbital sinus of the experimental animals at 0 and 22 d of the experiment to perform the serological study and the passive cutaneous anaphylaxis test. For the latter, the guinea pigs were sensitized passively with antibodies against the 4 antigen solutions. Enzyme-linked immunosorbent assay and Western blot were used to determine the specific antibodies of the isotypes immunoglobulin G1 and immunoglobulin G(Fc) developed against the same 4 antigen solutions. From these anaphylaxis and antibody-production tests, it was concluded that GM is hypoallergenic when compared with CM. The lactosera produced more closely grouped results, with values always below those of the corresponding milk. None of the proteins in the 4 immunizing solutions were identified as being their main allergen. These results show the hypoallergenicity of GM versus CM, and also that both casein and lactoserum proteins may be responsible for allergy in each case. To analyze the possibility of producing an innocuous food for those allergic to milk proteins, it would be of interest to identify the epitope(s) responsible for such allergenicity.     

陕西生鲜羊奶及其加工羊奶粉品质调研分析及相关性研究

为调查陕西省生鲜羊奶及羊奶粉品质随月份的变化规律,明确生鲜羊奶和羊奶粉品质之间的相关关系,该研究以2020年4月至11月某乳品企业在陕西不同地区的奶站收购的生鲜羊奶及其加工羊奶粉为试验样品,对其感官、理化和安全指标进行分析.结果表明,生鲜羊奶和羊奶粉在感官指标方面均符合国家标准要求;在理化指标方面,生鲜羊奶脂肪含量为3...     

On the importance of adequately choosing the ingredients of yoghurt and enriched milk for their antioxidant activity

The antioxidant activity of several dairy products, yoghurt enriched with green tea and lemon, fermented milk, yoghurt with strawberry pulp, 'low-calorie' yoghurt with inulin and milk enriched with vitamin E and their ingredients were analysed. Yoghurt enriched with green tea and lemon showed the best lipidic antioxidant capacity. All the dairy products analysed were very good OH· radical scavengers. The dairy products analysed were unable to scavenge H₂O₂ except green tea. The antioxidant activity of these samples resisted high temperatures in the Rancimat test; of the ingredients analysed, the best antioxidant activity was found for vitamin E followed by green tea, pectin, Lactobacillus acidophilus , lemon pulp and cornstarch. Antioxidant activity did not suffer variations during storage at an unfavourable temperature (40 °C), as demonstrated by the linoleic acid assay. Yoghurt enriched with green tea and lemon, yoghurt with strawberry pulp and low-calorie yoghurt with inulin produced the best results in the Trolox equivalent antioxidant capacity (TEAC) assay.     

True ileal amino acid digestibility of goat and cow milk infant formulas

Goat milk is used as an alternative to cow milk for the production of infant formulas. However, little is known about the protein quality and, specifically, about the digestible AA pattern of goat milk formulas compared with their cow milk counterparts. In this study, the true ileal AA digestibility of a goat milk infant formula was compared with a premium cow milk infant formula. The 3-wk-old piglet was used as a model for the 3-mo-old infant. Both milk formulas were prepared as described by the manufacturer, with titanium dioxide added as an indigestible marker. The formulas were fed to the piglets over a 2-wk trial period. Digesta from the terminal ileum were collected post euthanasia and analyzed for AA content, along with samples of the formulas. True AA digestibility was determined after correcting for endogenous AA loss at the terminal ileum of pigs fed an enzyme-hydrolyzed casein-based diet, followed by ultrafiltration (5,000 Da) of the digesta. Total urine and feces collection was also undertaken to determine the nitrogen retention from the diets. The true ileal AA digestibility was similar between the goat and cow milk infant formulas for all AA except Gly and Trp. There was no significant difference in the nitrogen retention of piglets fed the two different formulas. The goat milk infant formula and the premium cow milk infant formula were similar in terms of protein quality.     

牛乳低聚肽在益生菌酸奶中的应用

研究了牛乳低聚肽在益生菌酸奶中的应用。以益生菌酸乳发酵剂与传统酸乳发酵剂作为共同发酵荆．在鲜牛奶或还原奶中添：加益生菌生长促进因子一牛乳低聚肽，进行益生菌酸奶的研制。通过实验确定了最佳配方及生产工艺。     

Suitability of high-dynamic-pressure-treated milk for the production of yoghurt

The aim of this work was to evaluate, using the response surface methodology, the effects of different levels of high-pressure homogenization (HPH) on the microbiological and rheological characteristics of yoghurts having different contents of fat and milk solids. The HPH treatment of milk resulted a useful tool to obtain yoghurts having a greater variety of textures associated to a high microbiological quality. In fact, all the yoghurt types obtained by using milk treated with different levels of pressure were characterized by cell loads of the starter cultures higher than 8 log₁₀ cfu ml⁻¹ immediately after the fermentation and than 7 log₁₀ cfu ml⁻¹ after 60 days of storage at 4°C. The HPH treatment seems to favor the growth of Streptococcus thermophilus with respect to that of Lactobacillus delbrueckii subsp. bulgaricus, regardless of the level of pressure applied. The use of a Central Composite Design (CCD) and the polynomial models obtained permitted to individuate the levels of the three independent variables (pressure level, milk solids and fat concentration) able to maximize the growth of starters during the fermentation process, to minimize their viability loss during the refrigerated storage as well as to define their effects on the product viscosity.     

Supplementation with extruded linseed cake affects concentrations of conjugated linoleic acid and vaccenic acid in goat milk

The aim of this research was to determine the effect of adding extruded linseed cake to the dry diet of goats on the concentrations of conjugated linoleic acid (CLA) and vaccenic acid (VA) in milk fat. Thirty crossbreed dairy goats were divided into 3 groups. Their diet was supplemented with 0% (control group), 5% (low group), or 10% (high group) of extruded linseed cake (ELC), which supplied 0, 16, and 32 g/d of linseed fat, respectively. The milk fat percentage (overall mean 3.5%) and yield did not differ with the different diets, but fatty acid composition was affected by the ELC supplements. The inclusion of ELC in the diets did not influence the concentration of fatty acids from C6:0 to C12:0. The concentrations of C14:0 and C16:0 decreased as the quantity of ELC supplements increased. The concentrations (mg/100 mg of total fatty acid methyl esters) of VA (0.70, 1.23, and 1.39 in control, low, and high groups respectively) and cis-9,trans-11 CLA (0.63, 0.96, and 1.05 in control, low, and high groups, respectively) were increased by ELC supplements. The milk fat content of VA and cis- 9,trans-11 CLA were closely correlated (R² = 0.82). Desaturation of VA in the mammary gland to produce cis-9,trans-11 CLA was higher in the control group than in the groups with ELC diets. Extruded linseed cake supplementation to lactating goats may enhance the nutritional profile of milk lipids.     

Antimicrobial spectrum activity of bacteriocinogenic Staphylococcus strains isolated from goat and sheep milk

Bacteriocins have attracted great attention as potential alternatives to antibiotics and chemical food additives. In the present study, 243 Staphylococcus isolates from milk samples (n = 110) of goat and sheep herds located in Fars province, Iran, were screened for antimicrobial substance production. Twenty-eight isolates showed an antagonistic activity against the indicator strain Micrococcus luteus ATCC 4698. The susceptibility of all antimicrobial substances to proteolytic enzymes allowed us to consider them as bacteriocin-like inhibitory substances (BLIS). The term BLIS is applied to uncharacterized proteinaceous antimicrobials produced by gram-positive bacteria. Based on molecular identi?cation methods, the isolates belonged to the species Staphylococcus chromogenes, Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus pseudintermedius, Staphylococcus aureus, and Staphylococcus agnetis. Pulsed-?eld gel electrophoresis revealed a high level of genotype diversity among the Staph. chromogenes isolates. All of the isolates harbored nukA or bsaA2 genes, suggesting that their BLIS were related to nukacin or Bsa. The antimicrobial compounds from test strains were not effective against gram-negative pathogens, including Salmonella enterica serovar Typhimurium, Escherichia coli O157:H7, and Klebsiella pneumonia as well as the indicator mold Aspergillus fumigatus. All the gram-positive targets, including Bacillus cereus, Listeria monocytogenes, Enterococcus faecalis Ef37 (a tyramine-producer strain), Lactobacillus saerimneri 30a (a histamine-producer strain), and methicillin-resistant Staph. epidermidis, were inhibited by the Staph. chromogenes isolates. Staphylococcus haemolyticus 4S12 was able to inhibit the majority of gram-positive bacteria. Listeria monocytogenes strains were the only indicators sensitive to the antimicrobial agents produced by Staph. agnetis 4S97B. The other Staphylococcus strains were ineffective on all the organisms tested. Based on their inhibitory capacities, the BLIS produced by the Staph. chromogenes isolates seem to be interesting candidates for developing novel antimicrobial agents.     

Effect of the lactoperoxidase system on the activity of mesophilic cheese starter cultures in goat milk

The effect of goats’ milk lactoperoxidase (LP) system on the activity of commercially available mesophilic cheese starter cultures was investigated. The growth and acid production of the starter cultures were measured at 2 h intervals for 8 h in goats’ milk kept at 30°C. Most of the starter cultures examined were found to be sensitive to the LP system, but varied in their susceptibility to inhibition. The activity of the mixed starter cultures CHN11, CHN22, CHN19, DCC240 and Flora Danica Normal was strongly inhibited by the LP system. However, the mixed starter culture LL 50C showed resistance to the LP system. The single strain culture Lactococcus lactis subsp. lactis NCDO 605 was inhibited by the LP system. However, the cultures Lactococcus lactis subsp. diacetylactis NCDO 176 and Leuconostoc mesenteroides subsp. cremoris ATCC 33313 were insensitive to the LP system. The results of this study indicate the need for routine screening of starter cultures for resistance to the LP system before using them for cheesemaking from goats’ milk preserved by the LP system.     

山羊乳过氧化物酶体系及其延长保鲜期的研究

分析了关中奶山羊羊奶中乳过氧化物酶活性和硫氰根质量浓度,对室温下应用化学法激活乳过氧化物酶体系保鲜羊奶进行研究.结果表明,羊奶中乳过氧化物酶活性为(1.88±1.17)U/mL,硫氰根质量浓度为(1.57±0.35)mg/L.均低于牛奶中的质量浓度.在25℃贮藏温度下,添加20 mg/L硫氰化钠添加20 mg/L比添加18.5 mg/L有明显优势.在添加20 mg/L硫氰化钠20 mg/L的基础上添加过碳酸钠比过氧化氢有更好的效果,差异显著(p<0.05).在添加20 mg/L硫氰化钠20 mg/L的基础上添加58.2 mg/L过碳酸钠58.2 mg/L可获得最佳保鲜效果,与空白对照相比差异显著(p<0.05),延长保鲜时间约6 h.     

羊乳与牛乳理化特性比较

以莎能奶山羊羊乳为样品,利用乳样自动分析仪,氨基酸自动分析仪、等离子发射光谱、色谱分析对其基本成分、氨基酸组成及含量进行了分析和检测,并与牛乳理化特性进行比较,为科学合理地利用羊乳,生产具有独特功能的羊乳制品提供了理论依据。     

Influence of extruded soybeans with or without bicarbonate on milk performance and fatty acid composition of goat milk

The effects of extruded soybeans (ESB) included at 0, 10, or 20% of dry matter (DM) of the diet in combination with sodium bicarbonate (0 vs. 1% bicarbonate added to DM) on rumen fermentation characteristics, production parameters, and fatty acid (FA) profiles of milk fat were examined in 30 midlactation goats and 6 rumen-cannulated goats fed high-concentrate diets (30:70 forage-to-concentrate ratio) ad libitum in a 3 x 2 factorial design. Diets were fed as total mixed rations. The trial lasted 13 wk with the final 9 wk as the test period. Milk yield and composition were recorded each week throughout the trial. Individual samples of milk were taken in wk 4, 7, 10, 11, and 13 to determine FA profile of milk fat. Dry matter intake and intake of net energy for lactation were not affected by dietary treatments. Feeding ESB did not modify ruminal pH or volatile fatty acids concentration in the rumen fluid, but it increased the molar proportion of propionate. Feeding ESB increased fat-corrected milk, milk fat content, and fat yield compared with the control diets. There was no change in milk protein content when ESB were fed. Feeding ESB increased the proportions of oleic, linoleic, and linolenic acids in milk fat at the expense of most of the saturated FA. It also increased the n-6 to n-3 FA ratio of milk. The largest changes in milk yield and milk composition were generally obtained with ESB included at 20% of DM. The addition of sodium bicarbonate tended to increase ruminal pH, VFA concentrations in the rumen fluid, and the molar proportions of acetate. The addition of sodium bicarbonate increased milk fat content and fat yield, with no change in milk FA composition. It is concluded that during midlactation, the inclusion of ESB to 20% of DM prevented low milk fat content for goats fed high-concentrate diets, with no decrease in milk protein content. The addition of sodium bicarbonate may enhance the effects of ESB on milk fat content and fat yield.