发芽大豆酸奶的制备

以萌发至第4 天的发芽大豆和脱脂无糖乳粉为原料,制备发芽大豆酸奶。采用感官评价方法对产品风味进行评分,通过单因素试验确定发芽大豆与水的配比为1:4.5,以此配制豆芽浆;再以乳粉与水1:5.0 的配比制备乳液;正交试验确定最佳发酵条件：乳液在豆芽浆的质量分数60%、以100mL 豆芽乳计混合菌接种量为5mL、蔗糖添加量6g、发酵时间7h。最后对后熟时间对产品风味的影响进行实验,结果表明4℃条件下放置16h 以上风味最好。以本实验方法制备的发芽大豆酸奶具有滋味清香、凝固型酸奶固有的风味特征。     

Antioxidant and antigenotoxic effect of dairy products supplemented with red ginseng extract

The purpose of this study was to evaluate the antioxidant and antigenotoxic effect of dairy products milk (M) and yogurt (Y) after the addition of 2% red ginseng extract to milk (RM) and to yogurt (RY). Total phenolic content, total flavonoid content, 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, oxygen radical absorbance capacity, and total radical trapping antioxidant potential were determined in the samples. Furthermore, antigenotoxic effect of samples was measured, using comet assay in human leukocytes. Total phenolic content and total flavonoid content of RM [38.3 ± 0.8 mg of gallic acid equivalents (GAE)/100 g, 23.6 ± 0.1 mg of quercetin equivalents (QE)/100 g] and RY (41.1 ± 0.9 mg of GAE/100 g, 18.7 ± 0.1 mg of QE/100 g), respectively, were higher than those of M (6.31 ± 0.2 mg of GAE/100 g, 10.4 ± 0.1 mg of QE/100 g) and Y (8.1 ± 0.9 mg of GAE/100 g, 8.4 ± 0.2 mg of QE/100 g), respectively. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and oxygen radical absorbance capacity values increased significantly after the addition of 2% red ginseng in both. Additionally, the total radical trapping antioxidant potential in RM (787.7 ± 7.0 μg/mL) was lower than in M (2074.0 ± 28.4 μg/mL). The H₂O₂-induced DNA damage in RY (0.1 ± 0.0 mg/mL) was less than the damage in Y (0.4 ± 0.0 mg/mL), but we found no significant difference between M and RM. This study indicates that supplementation with red ginseng can fortify the antioxidant and antigenotoxic effects of dairy products effectively.     

Induction of phytochemical glyceollins accumulation in soybean following treatment with biotic elicitor (Aspergillus oryzae)

The different isoflavonoid phytoalexins produced by soybeans are known to possess antioxidant and estrogenic effects, with potential health benefits in humans. Enhanced production of phytoalexins by soybean plant will help in research efforts. In this study, the effects of stress induced by Aspergillus oryzae Lu brewing 3042 on the composition of wounded surface of Nigerian soybean seeds were analyzed. Glyceollin, one of the inducible phytoalexins produced by plants, were induced in the Nigerian soybeans variety through fungal infection. Glyceollins I, II, and III were separated by preparative high performance liquid chromatography (Prep-HPLC) from other phytochemicals and had purity of 97.5%. Results from the time course study indicated that the maximum concentration of glyceollins, 0.74 mg/g, occurred at day 3 in the soybean cotyledons inoculated with A. oryzae Lu brewing 3042. The soybean seeds soak time in water was examined and a suitable soak time of 4 h was found best in the accumulation of glyceollins after the soak time study was conducted. Cut or wounded surface of soybean cotyledons produced glyceollins upon fungal treatment as elicitor and the glyceollins were confirmed by the ultra performance liquid chromatography–mass spectrometry (UPLC–MS). Analysis of elicitor-treated Nigerian soybean extract showed that A. oryzae Lu brewing 3042 treatments achieved maximum concentration of phytoalexin glyceollins at 1.32 mg/g extract dry weight. These results indicate that using food-grade A. oryzae Lu brewing 3042 elicits the biosynthesis of phytoalexins, alters the secondary metabolite profiles of the soybeans and offers enhanced bioactivity of soybean as a functional food ingredient.     

Physiochemical Properties and Probiotic Survivability of Symbiotic Corn‐Based Yogurt‐Like Product

Corn is a major grain produced in northern China. Corn‐based functional food products are very limited. In this study, a symbiotic corn‐based yogurt‐like product was developed. Corn milk was prepared through grinding, extrusion and milling, and hydration processes. Corn extrudate was prepared under the optimized conditions of corn flour particle size <180 μm, moisture content of 15% and extrusion temperature at 130 °C. The corn milk was prepared from 8% corn extrudate suspension and then milled twice with 0.1% glyceryl monostearate and 0.1% sucrose ester as emulsifiers. The corn milk was mixed with sugar (5%), glucose (2%), soy protein isolate (0.75%), inulin (1%), polymerized whey protein (0.3%) and xanthan gum (0.09%) as thickening agents. The mixture was fermented at 35 °C for 6 h using a probiotic starter culture containing L. plantarum. Chemical composition (%) of the symbiotic corn‐based yogurt‐like product was: total solids (17.13 ± 0.31), protein (1.12 ± 0.03), fat (0.30 ± 0.05), carbohydrates (15.14 ± 0.19), and ash (0.16 ± 0.02), respectively. pH value of this symbiotic product decreased from 4.50 ± 0.03 to 3.88 ± 0.13 and the population of L. plantarum declined from 7.8 ± 0.09 to 7.1 ± 0.14 log CFU/mL during storage at 4 °C. SDS‐PAGE analysis showed that there were no changes in protein profile during storage. Texture and consistency were also stable during the period of this study. It can be concluded that a set‐type corn‐based symbiotic yogurt‐like product with good texture and stability was successfully developed that would be a good alternative to the dairy yogurt.     

Effect of the addition of pulse ingredients to milk on acid production by probiotic and yoghurt starter cultures

Pulses contain carbohydrates, proteins, minerals and vitamins which are essential requirements in the human diet and which could also serve as growth nutrients for probiotic and yogurt starter cultures. In this study, milk supplementation with pulse ingredients is examined as a means to increase the nutritional properties of yogurt and probiotic type beverages. The acid production rate of two yogurt starters (A and B) and two probiotic cultures (Lactobacillus rhamnosus and Lactobacillus acidophilus) was followed in milk supplemented with the following soy and pulse ingredients: pea protein, chickpea flour, lentil flour, pea fibre, soy protein concentrate and soy flour. The pulse ingredients had no negative effect on the acidification trends of the fermented milks. On the contrary, with yogurt culture B, pea fibre, pea protein and lentil flour significantly enhanced the acidification rate. All ingredients used for supplementation improved the acidification rate of probiotic cultures, and the highest effects were obtained with lentil and soy flour. Lentil flour had the lowest pH after 12 h which was significantly lower than the product enriched with the same quantity of skim milk powder. The effect of ingredient supplementation on the microbial composition (ratio of cocci to bacilli) of the yoghurt products was also examined. The ratio of cocci to bacilli was between 1.8 and 2.5 for all supplemented yogurt samples obtained with culture A, and these variations were not judged to be statistically significant (p < 0.05). With yogurt products obtained from culture B, however, there was a higher proportional level of lactobacilli in all supplemented samples, as compared to the milk control; the enhanced growth of the lactobacilli was particularly noted when lentil flour was added to milk.     

Production,nutritional and biological value of bambara groundnut (<Emphasis Type="Italic">Vigna subterranea</Emphasis>) milk and yoghurt

The purpose of this study was to assess the nutritional properties of Bambara milk and yoghurt. The milk was produced by aqueous extraction of flour obtained by dehulling the seeds followed by parboiling. It was then fermented using a mix culture of L. Bulgaricus, S. thermophilus and L. plantarum, followed by the evaluation of the protein biological value on rats. During the process of flour production, from the whole seeds to the flour, a significant drop in total polyphenol content (1.00?±?0.10–0.41?±?0.01 mg/100 g) and phytates (1.18?±?0.03–0.32?±?0.01 mg/100 g) was observed while the protein content increased (19.7?±?1.2–25.47?±?2.28 g/100 g). During the fermentation of the milk into yogurt, a significant decrease in phytate content (0.29?±?0.01–0.03?±?0.01 g/100 g), an increase in the protein content (1.8?±?0.1–2.6?±?0.1 g/100 g) and the protein digestibility (91.5–96%) were equally observed. Red blood cell, glycaemia, the ASAT and ALAT contents of rat bloods fed Bambara milk or yoghurt were not significantly different to rats fed casein as protein reference. In conclusion Bambara groundnut is a source of protein which the quality may be enhanced through processing of high value yogurt.     

米糠大豆酸奶发酵条件的优化

采用单因素实验和正交实验设计,对米糠大豆酸奶进行了研究,筛选出最佳工艺条件为:米糠与黄豆浆质量比为1/2,稳定剂为1:1海藻酸钠和琼脂,其添加量为米糠酶解液质量的0.13%,发酵温度为45℃,发酵时间为5 h。在此条件下,感官评定值为93.83分,乳酸含量是58.28 μg/mL,蛋白质含量为3.67 g/100 g。该植物性食品含有米糠以及大豆的重要天然营养成分,可以发挥米糠、大豆和酸奶的多种营养保健作用,为米糠大豆的开发利用提供了新的途径,也提高了米糠大豆的经济效用。     

Fermentation and Properties of Calcium-fortified Soy Milk Yogurt

Calcium-fortified soy milk yogurt containing 190 mg calcium/100g was produced and evaluated for textural and microstructural properties. The soy milk base contained 10% full fat soy flour, 2.25% soy protein isolate, 2.75% high fructose corn syrup, 1.55% calcium lactogluconate, and 1.25% potassium citrate. The mixture was heated 5 min at 80°C, cooled to 42°C, and inoculated with yogurt cultures. Calcium-fortified soy milk required a higher rate of inoculation (5%) than non-fortified soy milk (2.5%) and had higher titratable acidity and more syneresis. Calciumfortified soy milk yogurts showed comparable gel strength with that of commercial regular yogurt. Gels from nonfortified soy milk yogurts were hard and brittle. Addition of calcium did not significantly affect microstructure of the yogurts.     

Intramammary 25-hydroxyvitamin D3 treatment modulates innate immune responses to endotoxin-induced mastitis

Vitamin D signaling in response to pathogen-associated molecules contributes to activation of innate immune responses of bovine monocytes. We hypothesized that lipopolysaccharide (LPS) of bacteria associated with mastitis in dairy cows activates the vitamin D pathway in innate immune cells of the udder and that increasing availability of 25-hydroxyvitamin D₃ [25(OH)D₃] would augment expression of vitamin D-associated genes. The objective of this experiment was to determine the effects of intramammary LPS and 25(OH)D₃ treatments on activation of the vitamin D pathway and innate immune responses of mammary immune cells. Individual mammary quarters of 5 lactating cows were treated with placebo control, 100 μg of 25(OH)D₃, 5 μg of LPS, or a combination of 100 μg of 25(OH)D₃ and 5 μg of LPS. Somatic cells from milk were evaluated for percentage of neutrophil and macrophage populations and expression of genes associated with vitamin D metabolism and innate immunity. Data from samples collected from 4 to 12 h after challenge were analyzed for main effects of LPS and 25(OH)D₃ treatments, treatment interactions, and simple effects of 25(OH)D₃ treatment. Data from samples collected at the time of challenge were used as covariates. The percentages of neutrophils in milk at 8 h postchallenge were 58 ± 10, 82 ± 11, 89 ± 10, and 63 ± 10% of total cells in milk from control, 25(OH)D₃, LPS, and LPS plus 25(OH)D₃ glands, respectively, such that the interaction of LPS and 25(OH)D₃ was significant. Expression of the vitamin D 1α-hydroxylase (CYP27B1) and vitamin D receptor genes was upregulated by LPS treatment in total cells, macrophages, and neutrophils in milk. In addition, expression of the vitamin D 24-hydroxylase (CYP24A1) gene in milk somatic cells was upregulated by 25(OH)D₃ and LPS treatments. The inducible nitric oxide synthase (iNOS), chemokine (C-C-motif) ligand 5 (CCL5), β-defensin 3 (DEFB3), DEFB7, and DEFB10 genes were upregulated by LPS treatment in total cells and neutrophils from milk. Expression of iNOS in milk somatic cells tended to be affected by the interaction between LPS and 25(OH)D₃, such that 25(OH)D₃ tended to increase iNOS in the absence of LPS but not in the presence of LPS. Furthermore, expression of CCL5 in macrophages was downregulated by 25(OH)D₃. In conclusion, intramammary endotoxin challenge activates the vitamin D pathway in mammary macrophages and neutrophils, and intramammary 25(OH)D₃ treatment alters the percentage of neutrophils and expression of immune genes in milk somatic cells.     

Survival and detection of coliforms,Enterobacteriaceae, and gram-negative bacteria in Greek yogurt

Despite the widespread use of coliforms as indicator bacteria, increasing evidence suggests that the Enterobacteriaceae (EB) and total gram-negative groups more accurately reflect the hygienic status of high-temperature, short-time pasteurized milk and processing environments. If introduced into milk as postpasteurization contamination, these bacteria may grow to high levels and produce a wide range of sensory-related defects. However, limited information is available on the use and survival of bacterial hygiene indicators in dairy products outside of pasteurized fluid milk and cheese. The goal of this study was to (1) provide information on the survival of a diverse set of bacterial hygiene indicators in the low pH environment of Greek yogurt, (2) compare traditional and alternative detection methods for their ability to detect bacterial hygiene indicators in Greek yogurt, and (3) offer insight into optimal hygiene indicator groups for use in low-pH fermented dairy products. To this end, we screened 64 bacterial isolates, representing 24 dairy-relevant genera, for survival and detection in Greek yogurt using 5 testing methods. Before testing, isolates were inoculated into plain, 0% fat Greek yogurt (pH 4.35 to 4.65), followed by a 12-h hold period at 4 ± 1°C. Yogurts were subsequently tested using Coliform Petrifilm (3M, St. Paul, MN) to detect coliforms; Enterobacteriaceae Petrifilm (3M), violet red bile glucose agar and the D-Count (bioMérieux, Marcy-l'Étoile, France) to detect EB; and crystal violet tetrazolium agar (CVTA) to detect total gram-negative bacteria. Overall, the non-EB gram-negative isolates showed significantly larger log reductions 12 h after inoculation into Greek yogurt (based on bacterial numbers recovered on CVTA) compared with the coliform and noncoliform EB isolates tested. The methods evaluated varied in their ability to detect different microbial hygiene indicators in Greek yogurt. Crystal violet tetrazolium agar detected the highest portion of coliforms, whereas EB Petrifilm detected the highest portion of EB, as well as highest portion of total gram-negative bacteria. Additionally, the D-Count method allowed for faster detection of EB in yogurt by generating results in approximately 13 h rather than the 24 h required when using EB Petrifilm and violet red bile glucose agar. Results from this study indicate that the coliform and EB groups encompass a broad range of dairy-relevant gram-negative bacteria with the ability to survive in Greek yogurt, supporting their use as microbial hygiene indicator groups in low-pH fermented dairy products.     

Bog Bilberry (Vaccinium uliginosum L.) Extract Reduces Cultured Hep-G2, Caco-2, and 3T3-L1 Cell Viability,Affects Cell Cycle Progression,and Has Variable Effects on Membrane Permeability

ABSTRACT: Bog bilberry (Vaccinium uliginosum L.) is a blue-pigmented edible berry related to bilberry (Vaccinium myrtillus L.) and the common blueberry (Vaccinium corymbosum). The objective of this study was to investigate the effect of a bog bilberry anthocyanin extract (BBAE) on cell growth, membrane permeability, and cell cycle of 2 malignant cancer cell lines, Caco-2 and Hep-G2, and a nonmalignant murine 3T3-L1 cell line. BBAE contained 3 identified anthocyanins. The most abundant anthocyanin was cyanidin-3-glucoside (140.9 ± 2.6 μg/mg of dry weight), followed by malvidin-3-glucoside (10.3 ± 0.3 μg/mg) and malvidin-3-galactoside (8.1 ± 0.4 μg/mg). Hep-G2 LC50 was calculated to be 0.563 ± 0.04 mg/mL, Caco-2 LC50 was 0.390 ± 0.30 mg/mL and 0.214 ± 0.02 mg/mL for 3T3-L1 cells. LDH release, a marker of membrane permeability, was significantly increased in Hep-G2 cells and Caco-2 cells after 48 and 72 h compared to 24 h. The increase was 21% at 48 h and 57% at 72 h in Caco-2 cells and 66% and 139% in Hep-G2 cells compared to 24 h. However, 3T3-L1 cells showed an unexpected significant lower LDH activity (P ≤ 0.05) after 72 h of exposure corresponding to a 21% reduction in LDH release. BBAE treatment increased sub-G1 in all 3 cell lines without influencing cells in the G2/M phase. BBAE treatment reduced the growth and increased the accumulation of sub-G1 cells in 2 malignant and 1 nonmalignant cell line; however, the effect on membrane permeability differs considerably between the malignant and nonmalignant cells and may in part be due to differences in cellular membrane composition.     

Physico-chemical and sensory properties of yogurt from ultrafiltreted soy milk concentrate added with inulin

The total solids required for yogurt preparation were obtained by soy milk microfiltration and ultrafiltration. Inulin was incorporated at the level of 20–70 g/L, and the soy milk containing inulin was fermented using conventional microorganisms. The chemical, physical and sensory properties of the products were evaluated. The membrane concentration of soy proteins leads to yogurts with an increase of 59 g/L of proteins and 15 g/L of vegetable fats, reducing ash and anti-nutrients content. The clot had high stability and protein concentration generated a buffer effect smoothing the acidity and the flavor obtained is more agreeable. In addition, the proteins were concentrated without thermal treatment. As the inulin content increased, creaminess and viscosity increased as well. The products prepared presented nice smell, flavor and color, being the sample with higher global acceptability the yogurt with 50 g/L of inulin (P < 0.05).     

凝固型黑豆酸豆奶生产工艺的研究

目的 确定以带皮黑豆为主要原料的凝固型乳酸菌发酵黑豆酸豆奶的生产工艺.方法 将带皮黑豆制备成培养液,通过对发酵产物进行感官评价,从干酪乳杆菌FJAT-7928、嗜热链球菌FJAT-7927和植物乳杆菌FJAT-7926的不同组合中筛选出最佳组合作为发酵剂,通过单因素和正交试验确定培养液中乳糖、番茄汁、奶粉和白砂糖的最佳...     

Antioxidant activity and flavor compounds of hickory yogurt

Hickory milk and reconstituted milk (about 12 g/100 g total solid) were mixed in the proportion of 3:7 by volume to prepare hickory milk yogurt. Cow milk yogurt was used as control. The acidity and total count of lactic acid bacteria of hickory milk yogurt were not significantly different from cow milk yogurt (p > 0.05). Compared with cow milk yogurt, hickory milk yogurt had higher total solids, fat, crude protein, and amino acids, but lower ash and not-fat solids. Sensory evaluation showed that the appearance and flavor scores of hickory milk yogurt had no significant difference from cow milk yogurt (p > 0.05), but the texture score was significantly higher (p < 0.05). IC₅₀ values in relation to 1,1-diphenyl-2-picrylhydrazyl scavenging activity and inhibition of lipid peroxidation (46.88 and 26.70 g/L) of hickory milk yogurt were significantly lower than those of cow milk yogurt which suggested that the antioxidant activity of hickory milk yogurt was significantly higher than cow milk yogurt (p < 0.05). There were 30 and 28 kinds of volatile compounds identified in hickory milk yogurt and cow milk yogurt, respectively. Compared with cow milk yogurt, the concentration of acetaldehyde, hexanal, nonanal, 2-nonanone, caproic acid, heptylic acid, and nonanoic acid in hickory milk yogurt increased significantly, and the concentration of benzaldehyde, 2,3-pentanedione, 2,3-butanedione, 3-hydroxy-2-butanone, acetic acid, butyric acid, and benzoic acid decreased significantly (p < 0.05).     

RAPID HIGH PERFORMANCE LIQUID CHROMATOGRAPHIC DETECTION OF FUROSINE (ε‐N‐2‐FUROYLMETHYL‐L‐LYSINE) IN YOGURT AND CHEESE MARKETED IN TURKEY*

Furosine (ε‐N‐2‐furoylmethyl‐L‐lysine) content determination in the yogurt and different cheese types (pickled white, kasar, processed, canned tulum, blue‐veined and mozzarella cheeses) marketed in Turkey was performed using ion‐pair reversed‐phase high performance liquid chromatography (RP‐HPLC). Calibration study (R² = 0.9999), analytical method validation and recovery studies gave satisfactory results. The lowest furosine values were observed in pickled white cheeses (5.35 ± 0.01 to 7.28 ± 0.02 mg/100 g protein). All cheeses except pickled white showed furosine values between 182.16 ± 0.12 (canned tulum) and 261.32 ± 0.10 mg/100 g protein (ripened kasar). The highest content of furosine was observed in whole yogurt (316.47 ± 0.17 mg/100 g protein) which could be because of severe heat treatment and the addition of milk powder during the manufacturing process. The method provides a rapid, reproducible and accurate determination of this Amadori compound (ε‐deoxy‐fructosyl‐lysine) in yogurt and cheese samples.     

Influence of lupin-based milk alternative heat treatment and exopolysaccharide-producing lactic acid bacteria on the physical characteristics of lupin-based yogurt alternatives

In the present study we investigated the influence of heat treatment of lupin-based (LB) milk alternatives and different exopolysaccharide (EPS)-producing lactic acid bacteria on the physical characteristics of set-type LB yogurt alternatives. LB milk alternatives, obtained from protein isolate of Lupinus angustifolius cv. Boregine, were either pasteurized at 80 °C for 60 s or ultra-high temperature (UHT) heated at 140 °C for 10 s and was fermented with Lactobacillus plantarum TMW 1.460 and 1.1468, Pediococcus pentosaceus BGT B34 and Lactobacillus brevis BGT L150. Fermentation duration was strongly affected by heat treatment: different strains needed between 25 to 35 h in UHT LB milk alternative to reach a pH of 4.5 compared to 14 to 24 h in pasteurized LB milk alternative. EPS extraction revealed slightly higher amounts of EPS for UHT LB yogurt alternatives (~ 0.5–0.9 g/l; pasteurized: ~ 0.4–0.7 g/l). The more intensive heat treatment (UHT) resulted also in better rheological (apparent viscosity, hysteresis loop area, flow point, elastic, viscous and complex modulus) and textural properties (firmness, consistency, cohesiveness and index of viscosity) of the investigated LB yogurt alternatives. Furthermore, LB yogurt alternatives out of UHT milk alternative revealed a lower tendency to syneresis, measured with siphon and centrifugation method. This work contributes to the fundamental knowledge of the textural properties of LB yogurt alternatives.     

Replacing soybean meal with high-oil pumpkin seed cake in the diet of lactating Holstein dairy cows modulated rumen bacteria and milk fatty acid profile

This research aimed to investigate the effects of replacing soybean meal with high-oil pumpkin seed cake (HOPSC) on ruminal fermentation, lactation performance, milk fatty acid, and ruminal bacterial community in Chinese dairy cows. Six multiparous Chinese Holstein cows at 105.50 ± 5.24 d in milk (mean ± standard deviation) and 36.63 ± 0.74 kg/d of milk yield were randomly allocated, in a 3 × 3 Latin square design, to 3 dietary treatments in which HOPSC replaced soybean meal. Group 1 was the basal diet with no HOPSC (0HOPSC); group 2 was a 50% replacement of soybean meal with HOPSC and dried distillers grains with solubles (DDGS; 50HOPSC), and group 3 was a 100% replacement of soybean meal with HOPSC and DDGS (100HOPSC). We found no difference in the quantity of milk produced or milk composition among the 3 treatment groups. Feed efficiency tended to increase linearly as more HOPSC was consumed. In addition, rumen fermentation was not influenced when soybean meal was replaced with HOPSC and DDGS; the relative abundance of ruminal bacteria at the phylum and genus levels was altered. We also observed that as the level of HOPSC supplementation increased, the relative abundance of Firmicutes and Tenericutes linearly increased, whereas that of Bacteroidetes decreased. However, with increasing HOPSC supplementation, the relative abundance of Ruminococcus decreased linearly at the genus level in the rumen, and the relative abundance of Prevotella showed a linear downward tendency. Changes in dietary composition and rumen bacteria had no significant effect on the fatty acid composition of milk. In conclusion, our results indicated that replacing soybean meal with a combination of HOPSC and DDGS can meet the nutritional needs of high-yielding dairy cows without adversely affecting milk yield and quality; however, the composition of rumen bacteria could be modified. Further study is required to investigate the effects of long-term feeding of HOPSC on rumen fermentation and performance of dairy cows.     

Short communication: Influence of an aqueous myrrh suspension on yogurt culture bacteria over yogurt shelf life

Myrrh is an essential oil and natural flavoring approved by the US Food and Drug Administration, and it has antibacterial and antifungal activity against pathogens. Our objective was to determine the effect of an aqueous myrrh suspension on Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus counts in peptone solution and yogurt, as well as pH and titratable acidity of yogurt during 5 wk of storage at 1 to 4°C. The myrrh suspension (10% wt/vol) was prepared and incorporated into a pure culture dilution in peptone and into yogurt mix at a 1% (vol/vol) level. A control with no myrrh was also prepared, and 3 replications were conducted. Streptococcus thermophilus were enumerated using Streptococcus thermophilus agar with aerobic incubation at 37°C for 24 h, and Lactobacillus delbrueckii ssp. bulgaricus were enumerated using de Man, Rogosa, and Sharpe agar adjusted to pH 5.2, with anaerobic incubation at 43°C for 72 h. During the 8-h period after inoculation, S. thermophilus and L. delbrueckii ssp. bulgaricus counts in peptone solution at 37°C and 43°C, respectively, were not significantly different in the presence or absence of the aqueous myrrh suspension. Counts of S. thermophilus in yogurt containing myrrh (mean ± SD; 4.96 ± 0.58 log cfu/mL) were not significantly different from those in the control yogurt (4.87 ± 0.39 log cfu/mL). The log counts for L. delbrueckii ssp. bulgaricus in yogurt containing myrrh (5.04 ± 1.44 log cfu/mL) and those of the control (5.52 ± 1.81 log cfu/mL) did not differ, and the counts remained within 1 log of each other throughout 5 wk of storage. The pH of the yogurts containing the aqueous myrrh suspension was not significantly different from that of the control yogurts, and their pH values were within 0.1 pH unit of each other in any given week. Titratable acidity values remained steady around 1.1 to 1.2% lactic acid for both yogurt types throughout the storage period, with no significant differences between them. Yogurt culture bacteria can survive in the presence of a myrrh suspension in yogurt with no significant change in pH or titratable acidity. Therefore, it may be beneficial to add an aqueous myrrh suspension to yogurt.     

Feed additives containing sequestrant clay minerals and inactivated yeast reduce aflatoxin excretion in milk of dairy cows

The objective was to evaluate the efficacy of 2 dietary mycotoxin sequestrants, Toxy-Nil (TN) or Unike Plus (UP), in reducing aflatoxin (AF) M₁ concentrations in milk of dairy cows challenged with dietary AF. Thirty-two mid-lactation Holstein cows were blocked by parity, days in milk, and milk yield and were randomly assigned within block to receive one of the following treatments: (1) 2.8 mg of AF/cow per d (positive control, PC), (2) 2.8 mg of AF + 100 g of TN/cow per d, (3) 2.8 mg of AF + 100 g of UP/cow per d, or (4) no AF and no additives (negative control, NC). For 7 d, treatments, dispersed in 150 g of sweet feed carrier, were top-dressed twice daily by mixing into the top portion of the TMR at each feeding. After the experimental period, cows were fed the NC diet and clearance of AFM₁ via milk was monitored for 7 d. Feed and water were available ad libitum throughout the trial. Treatments had no effect on feed intake, milk yield, milk composition, or milk somatic cell count. Relative intake of AF was similar among PC, TN, and UP, averaging 106.5, 107.6, and 102.5 ± 2.9 μg/kg of diet dry matter, respectively. Relative intake of mycotoxin sequestrants was similar between TN and UP, averaging 0.4 and 0.4 ± 0.1% of diet dry matter, respectively. Concentration and mass of AFM₁ secreted in milk and in urine were similar between TN and UP, but were lower than PC; concentrations in milk averaged 0.2, 0.3, and 0.6 ± 0.1 μg/kg, respectively, and mass secreted in milk averaged 8.1, 9.8, and 20.5 ± 1.7 μg/d. Concentrations in urine averaged 6.9, 7.4, and 14.2 ± 1.5 μg/L, respectively, and mass secreted in urine averaged 225.7, 250.8, and 521.6 ± 53.1 μg/d. Likewise, concentration and mass of free AF excreted in feces were similar between TN and UP, but were lower than PC; concentrations averaged 7.7, 8.9, and 12.4 ± 0.6 μg/kg, respectively, and mass excreted averaged 57.8, 69.6, and 95.6 ± 4.8 μg/d. Transfer of AF from feed to AFM₁ in milk was reduced by 63 and 52%, and in urine, by 57 and 52% for TN and UP, respectively. Transfer of AF from feed to free AF in feces was reduced by 38 and 26% for TN and UP, respectively. The clearance rate of AFM₁ in milk did not differ among PC, TN, and UP (46.1, 66.5, and 50.0 ± 6.7%/d, respectively). Results indicate that dietary inclusion of 100 g of TN or UP significantly reduced AFM₁ in milk of cows consuming TMR containing approximately 105 μg of AF/kg of diet dry matter. Results also suggest that both TN and UP reduced absorption of AF.