1 株牦牛源产细菌素植物乳杆菌的益生特性分析

为研究1 株从牦牛体内分离筛选出的高产细菌素的植物乳杆菌（Lactobacillus plantarum）SWUN5815的益生特性,本研究通过测定其抗菌活性、耐酸耐胆盐能力、黏附能力及对小鼠体质量和肠黏膜免疫影响评价其益生能力。结果表明：该菌株对牦牛源食源性致病微生物具有很强的广谱抑菌活性;在pH?2和pH?3时存活率分别为58.2%和86.9%,胆盐质量分数0.3%时存活率为66.8%,具有良好的耐酸耐胆盐能力;对Caco-2细胞黏附率为42%;对常用的抗生素敏感,不具有耐药性。短期喂服植物乳杆菌SWUN5815可以显著提高小鼠体质量（P＜0.01）,同时还可提升小鼠肠道SIgA的表达水平（P＜0.01）。综上所述,本研究分离得到的植物乳杆菌SWUN5815能很好地适应胃肠环境压力,有效提高小鼠的体质量和免疫功能,可作为候选益生性菌株。     

Safety Evaluation of Green Tea Polyphenols Consumption in Middle‐aged Ovariectomized Rat Model

This work evaluates chronic safety in middle‐aged ovariectomized rats supplemented with different dosages of green tea polyphenols (GTP) in drinking water. The experiment used 6‐mo‐old sham (n = 39) and ovariectomized (OVX, n = 143) female rats. All sham (n = 39) and 39 of the OVX animals received no GTP treatment and their samples were collected for outcome measures at baseline, 3 mo, and 6 mo (n = 13 per group for each). The remaining OVX animals were randomized into 4 groups receiving 0.15%, 0.5%, 1%, and 1.5% (n = 26 for each) of GTP (wt/vol), respectively, in drinking water for 3 and 6 mo. No mortality or abnormal treatment‐related findings in clinical observations or ophthalmologic examinations were noted. No treatment‐related macroscopic or microscopic findings were noted for animals administered 1.5% GTP supplementation. Throughout the study, there was no difference in the body weight among all OVX groups. In all OVX groups, feed intake and water consumption significantly decreased with GTP dose throughout the study period. At 6 mo, GTP intake did not affect hematology, clinical chemistry, and urinalysis, except for phosphorus and blood urea nitrogen (increased), total cholesterol, lactate dehydrogenase, and urine pH (decreased). This study reveals that the no‐observed‐adverse‐effect level (NOAEL) of GTP is 1.5% (wt/vol) in drinking water, the highest dose used in this study.     

Heat-moisture treatment of high-amylose corn starch increases dietary fiber content and lowers plasma cholesterol in ovariectomized rats

ABSTRACT:  The effect of dietary high-amylose corn starch (HACS) of varying dietary fiber (DF) content on plasma cholesterol was examined in ovariectomized (OVX) rats. Gelatinized normal corn starch (G-CS) was used as a reference. OVX rats were fed a fiber-free purified diet containing G-CS, HACS, gelatinized high-amylose corn starch (G-HACS), or heat-moisture treated HACS (HM-HACS) at 400 g starch/kg diet for 21 d. The DF content of G-CS, HACS, G-HACS, and HM-HACS measured by the AOAC method was 0.1, 19.3, 2.4, and 64.5 g/100 g, respectively. The dry weight of cecal contents, cecal wall weight, the amount of short chain fatty acids in cecal contents, the amount of bile acids in small intestinal contents, and fecal excretion of neutral sterols increased logarithmically with increasing DF, while total plasma cholesterol concentration decreased. On the other hand, hepatic CYP7A1 activity, fecal dry weight, and fecal excretion of bile acids increased linearly with increasing DF, while body weight gain decreased. The hypocholesterolemic effect of HACS in OVX-rats appeared to be more effective by heat-moisture treatment.     

Protective effects of bovine colostrum acid proteins on bone loss of ovariectomized rats and the ingredients identification

Scope: Milk basic proteins and bovine colostrum extracts have preventive effects on osteoporosis. However, the effects of bovine colostrum acidic proteins (BCAP) on properties of bone have not been reported. This study investigated the effect of BCAP on the prevention of bone loss in ovariectomized (OVX) rats. Methods and results: Forty‐eight 3‐month old female Sprague–Dawley rats were OVX and another 12 rats underwent a sham operation (Sham). The OVX rats were randomly separated into four groups, i.e. OVX control, OVX plus 2 mg/day BCAP, OVX plus 10 mg/day BCAP, and OVX plus 50 mg/day BCAP, and were gavaged once per day for 12 wk. The effects on bone mineral content, bone mineral density, microarchitecture and biomechanical properties were determined. The bioactive ingredients in BCAP were isolated and identified. Results showed that BCAP increased the bone mineral content and bone mineral density of the femur in a dose‐dependent manner. Scanning electron microscope observation and mechanical testing further confirmed the positive effects of BCAP. These positive effects attribute to the fact that osteopontin, lactoferrin, epidermal growth factor and insulin‐like growth factor‐2 are the dominant proteins in BCAP. Conclusions: BCAP (2–50 mg/day) could prevent osteoporosis caused by bone loss in OVX rats.     

Bile salt deconjugation activity of Propionibacterium strains and their cholesterol co‐precipitation abilities

The present study investigated the deconjugation of bile salts and co‐precipitation of cholesterol with deconjugated bile salts by seven Propionibacterium spp. strains in vitro. Propionibacterium spp. could deconjugate sodium glycocholate (1.53–5.31 mM) and sodium taurocholate (0.08–0.25 mM) bile salts. The highest cholesterol precipitation (47.8 µg/mL) was determined with Propionibacterium freudenreichii subsp. freudenreichii SP3 strain in a 0.15% oxgall‐containing medium. Significant (P < 0.05) correlations were observed between cholesterol co‐precipitation and deconjugation of sodium glycocholate among the strains. In vitro bile salt deconjugation activity studies of P. freudenreichii subsp. freudenreichii SP3 strain revealed that this strain may have potential as a probiotic strain for deconjugation of bile salts in vivo studies.     

Anti‐adhesive effects of sialic acid and Lactobacillus plantarum on Staphylococcus aureus in vitro

Staphylococcus aureus (S. aureus) is a common food‐borne pathogen that causes severe diseases after adhesion to epithelial cells. Lactobacillus inhibits pathogenic bacterial adhesion and infection. In addition, sialic acid (SA) is widely known for its beneficial biological functions. A new way of reducing the occurrence of diseases and curbing the overuse of antibiotics is ingesting prebiotics and probiotics that regulate the intestinal flora. In this study, we first evaluated the anti‐adhesive effects of several strains of Lactobacillus on S. aureus. The study revealed that the S. aureus adhesion was inhibited by all the strains of Lactobacillus. Besides, the rate of inhibition by L. plantarum Z‐4 was significantly higher than other Lactobacillus species. We then investigated the effects of different SA concentrations (40, 100, 150, 200, and 260 μg/ml) on the growth and adhesion characteristics of L. plantarum and S. aureus. The results showed that SA influences bacterial adhesion by regulating the bacteria's growth characteristics. Finally, the effects of SA combined with Lactobacillus on the adhesion of S. aureus were assessed by competition, exclusion and displacement methods. SA with a concentration of 260 μg/mL combined with L. plantarum had the highest inhibition effect on the competition assays. In addition, the expression of S. aureus adhesion‐related genes was reduced. This provides a new perspective on the application of SA and/or L. plantarum and its potential to resist adhesion of S. aureus.     

MILK BASIC PROTEIN ENHANCES THE BONE STRENGTH IN OVARIECTOMIZED RATS

We studied the effects of milk basic protein (MBP) on bone metabolism in ovariectomized (OVX) rats. Five‐week‐old female Sprague‐Dawley rats were ovariectomized and fed a low‐calcium diet (0.009% Ca) for 5 weeks. The OVX rats were divided into three experimental groups: Control group (20% casein), MBP‐L group (19.9% casein, 0.1% MBP), and MBP‐H (19% casein, 1% MBP) of six animals. The rats were fed each experimental diet for 3 weeks. The bone breaking strength and energy of femur in the MBP‐H group were significantly higher than those in the control group. The bone breaking energy of femur in the MBP‐L group was also significantly higher than those in the control group. There were no differences in the amount of femoral calcium and phosphorus among the three groups, however, the amounts of femoral proline, hydroxyproline and hydroxylysine (typical amino acids of collagen) in the MBP groups were significantly higher than those in the control group. These data indicate that MBP in the whey protein increases the amount of the bone collagen and enhances the bone strength.     

Suitability of Bifidobacterium spp. and Lactobacillus plantarum as Probiotics Intended for Fruit Juices Containing Citrus Extracts

A strain of Lactobacillus plantarum and 4 strains of bifidobacteria were inoculated in apple juice and in a commercial beverage labeled as “red‐fruit juice,” containing citrus extracts as natural preservatives; the suitability of the probiotics was evaluated in relation to their resistance to 2 kinds of citrus extracts (biocitro and lemon extract), survival in juices at 4 and 37 °C, and inhibition of Zygosaccharomyces bailii. Cell count of L. plantarum and bifidobacteria over time was fitted through the Weibull equation, for the evaluation of the first reduction time (δ), death time, and microbiological shelf life (the break‐point was set to 7 log cfu/mL). Bifidobacterium animalis subsp. lactis experienced the highest δ‐value (23.21 d) and death time (96.59 d) in the red‐fruit juice at 4 °C, whereas L. plantarum was the most promising strain in apple juice at 37 °C. Biocitro and lemon extract did not exert a biocidal effect toward probiotics; moreover, the probiotics controlled the growth of Z. bailii and the combination of L. plantarum with 40 ppm of biocitro reduced the level of the yeast after 18 d by 2 log cfu/mL.     

多孔淀粉对卵巢切除大鼠脂质代谢的影响

目的:研究多孔淀粉对卵巢切除大鼠脂质代谢的影响。方法:将24只雌性SD大鼠按体质量随机分为3组,其中一组进行伪切除手术,其余两组进行双侧卵巢切除手术,手术后恢复1周,分别饲喂相应饲料。4周后,检测大鼠血脂、肝脂、粪便中中性固醇含量和胆汁酸含量以及肠道中典型微生物数量、短链脂肪酸浓度等指标。结果:多孔淀粉的替代添加可以显著降低大鼠血浆中甘油三酯(triglyceride,TG)、TG与高密度脂蛋白胆固醇(high-density lipoprotein cholesterol,HDL-C)的比值(TG/HDL-C)、肝脏中总胆固醇(total cholesterol,TC)、TG和脂肪总质量,显著减少腹部脂肪堆积(P0.05);显著增加粪便中中性固醇和胆汁酸的排泄量(P0.05);同时促进肠道中益生菌增殖和短链脂肪酸浓度的提高。结论:多孔淀粉对雌激素缺乏引起的高脂血症具有较好的降脂、降胆固醇效果,对内源性脂质代谢紊乱具有较好的缓解作用。     

Selenium enriched green tea increase stability of Lactobacillus casei and Lactobacillus plantarum in chitosan coated alginate microcapsules during exposure to simulated gastrointestinal and refrigerated conditions

The effects of selenium enriched green tea (SGT; 85.8–96 mg/kg) in different concentrations of 1 g and 2 g/100 mL, on the in vitro exposure to simulated gastrointestinal juice and refrigerated storage of encapsulated Lactobacillus casei and Lactobacillus plantarum were investigated in chitosan coated alginate beads. The encapsulation yield of viable cells in chitosan coated alginate beads with and without SGT was not significantly different (P < 0.05). These results together with the study about the survival of probiotic bacteria in microspheres with SGT during storage at 4 °C, demonstrated significantly higher number (P < 0.05) of survival bacteria in microcapsules with SGT 2 g/100 mL. Microencapsulated L. casei and L. plantarum with SGT 1 g and 2 g/100 mL were resistant to simulated gastric conditions (pH 2.0, 2 h) and bile solution (3 g/100 mL, 2 h) resulting in significantly (P < 0.05) improved survival when compared with microencapsulation without SGT addition.     

Pharmacokinetics of xanthohumol and metabolites in rats after oral and intravenous administration

Scope Xanthohumol (XN), a dietary flavonoid found in hops, may have health‐protective actions against cardiovascular disease and type 2 diabetes. Yet, there are limited data on the pharmacokinetics (PK) of XN. This study provides PK parameters for XN and its major metabolites in rats. Methods and results A PK study was conducted in male jugular vein‐cannulated Sprague‐Dawley rats. Rats (n = 12/group) received an intravenous (IV) injection (1.86 mg/kg BW) or an oral gavage of a low (1.86 mg/kg BW), medium (5.64 mg/kg BW), or high (16.9 mg/kg BW) dose of XN. Plasma samples were analyzed for XN and its metabolites using LC‐MS/MS. The maximum concentration (C_max) and area under the curve (AUC_{0‐96 h}) of total XN (free and conjugated) were 2.9±0.1 mg/L and 2.5±0.3 h^* mg/L in IV group, 0.019±0.002 mg/L and 0.84±0.17 h^* mg/L in the oral low group, 0.043±0.002 mg/L and 1.03±0.12 h^* mg/L in the oral medium group, and 0.15±0.01 mg/L and 2.49±0.10 h^* mg/L in the oral high group. Conclusion The bioavailability of XN is dose‐dependent and approximately 0.33, 0.13, and 0.11 in rats, for the low‐, medium‐, and high‐dose groups, respectively.     

Interaction and inactivation of Listeria and Lactobacillus cells in single and mixed species biofilms exposed to different disinfectants

Listeria spp. are ubiquitously found in both the natural and the food processing environment, of which Listeria monocytogenes is of an important health risk. Here, we report on the formation of single and mixed species biofilms of L. monocytogenes/Listeria innocua and Lactobacillus plantarum strains in 24‐well polystyrene microtiter plates and on the inactivation of 24‐hr and 72‐hr biofilms using quaternary ammonium compound‐, tertiary alkyl amine‐, and chlorine‐based disinfectants. Fluorescent in situ hybridization (FISH) and LIVE/DEAD BacLight staining were applied for 72‐hr L. innocua–L. plantarum mixed biofilms in the LabTek system for the species identification and the reaction of biofilm cells to disinfectants, respectively. L. monocytogenes/L. innocua were more resistant to disinfectants in 72‐hr than in 24‐hr biofilms, whereas L. plantarum strains did not show any significant differences between 72‐hr and 24‐hr biofilms. Furthermore, L. innocua when grown with L. plantarum was more resistant to all disinfection treatments, indicating a protective effect from lactobacilli in the mixed species biofilm. The biofilm formation and reaction to disinfectants, microscopically verified using fluorescence in situ hybridization and LIVE/DEAD staining, showed that L. innocua and L. plantarum form a dense mixed biofilm and also suggested the shielding effect of L. plantarum on L. innocua in the mixed species biofilm.     

Dietary calcium decreases plasma cholesterol by down‐regulation of intestinal Niemann–Pick C1 like 1 and microsomal triacylglycerol transport protein and up‐regulation of CYP7A1 and ABCG 5/8 in hamsters

Scope: It has been shown that calcium supplementation favorably modifies plasma lipoprotein profile in postmenopausal women. The present study investigated the interaction of dietary calcium with genes of transporters, receptors and enzymes involved in cholesterol metabolism. Methods and results: Forty‐eight ovariectomized hamsters were fed one of the four diets containing 0, 2, 6 and 8 g calcium per kg. Plasma total cholesterol (TC), triacylglycerols (TG), and non‐high density lipoprotein cholesterol were dose‐dependently decreased, whereas high‐density lipoprotein cholesterol (HDL‐C) was dose‐dependently increased with the increasing dietary calcium levels. Dietary calcium had no effect on protein mass of hepatic sterol regulatory element binding protein‐2 (SREBP), liver X receptor‐alpha (LXR), 3‐hydroxy‐3‐methylglutaryl‐CoA reductase (HMGR), LDL receptor (LDLR) and cholesterol‐7α‐hydroxylase (CYP7A1). However, dietary calcium up‐regulated the mRNA levels of hepatic CYP7A1 and intestinal ATP binding cassette transporters (ABCG5/8) whereas it down‐regulated the intestinal Niemann‐Pick C1 like 1 (NPC1L1) and microsomal triacylglycerol transport protein (MTP). In addition, dietary calcium increased the activity of intestinal acyl coenzyme A: cholesterol acyltransferase 2, while it decreased plasma cholesteryl ester transport protein (CETP). Conclusion: Beneficial modification of lipoprotein profile by dietary calcium was mediated by sequestering bile acid absorption and enhancing excretion of fecal cholesterol, via up‐regulation of mRNA CYP7A1 and intestinal ABCG 5/8 with down‐regulation of mRNA NPC1L1 and MTP.     

Bioavailability of Isoflavone Metabolites After Korean Fermented Soybean Paste (Doenjang) Ingestion in Estrogen‐Deficient Rats

Doenjang (DJ), a fermented soybean product used in soups, stews, and sauces, contains high quality proteins, fats, vitamins, minerals, and other functional ingredients, including isoflavones and saponins. This study investigated whether DJ improves the bioavailability of isoflavones compared to boiled soybean (BS) in sham‐operated or ovariectomized (OVX) rats. We also examined the effects of ovariectomy on the differences in bioavailability of isoflavones. BS and DJ were administered in sham‐operated and OVX rats, and blood samples were collected. Twenty‐six isoflavone‐derived metabolites were identified. Pharmacokinetic analysis revealed that T_1/2 values of the individual isoflavone metabolites were most different in sham and OVX rats, even after the same sample treatment; however, T_max values were significant different in a few metabolites such as daidzein 4′‐glucuronide, daidzein 4′‐sulfate, 2‐(4‐hydroxyphenyl)propionic acid, and benzoic acid. For most of the individual metabolites, C_max was higher in both sham and OVX rats administered BS than those administered DJ. The AUC was generally lower in OVX rats than in sham rats. The AUC of daidzein and genistein in BS‐fed sham rats was approximately 1.7‐fold higher than those administered DJ, whereas glycitein was detected only in the DJ group. No significant differences in AUC of daidzein and genistein were observed between BS and DJ administration in OVX rats, although the total isoflavone content of DJ was lower; thus, DJ‐mediated isoflavone bioavailability was more effective in OVX rats. Similar tendencies were observed for phase II and gut‐mediated metabolites. These results suggested that DJ enhanced isoflavone bioavailability under estrogen deficiency, even when the total isoflavone content was decreased by fermentation.     

薛荔籽果胶对高脂膳食去势大鼠脂质代谢及盲肠内环境的影响

目的：研究薛荔籽果胶对高脂膳食去势大鼠脂质代谢及盲肠内环境的影响。方法：将40 只健康雌性Sprague-Dawley（SD）大鼠随机分为5 组,其中1 组作为空白对照进行卵巢伪切除手术（Sham组）,另外4 组进行双侧卵巢切除手术（OVX组）,1 周后分为模型对照组和饲喂5%、10%、15%薛荔籽果胶低、中、高剂量组。喂养4 周后解剖测定大鼠血脂和肝脂含量、肝脏组织形态,以及盲肠内容物含水率和短链脂肪酸（shortchainfatty acids,SCFAs）含量等指标。结果：模型对照组大鼠的血脂以及肝脏质量、肝脏脂肪含量、每克肝脏中胆固醇、甘油三酯含量显著高于双侧卵巢伪切除组（P＜0.05）。薛荔籽果胶对双侧卵巢切除大鼠的血脂浓度几乎没有影响,而肝脏质量有升高趋势,但无显著性差异;同时能显著升高盲肠壁湿质量、盲肠壁表面积、盲肠组织湿质量和盲肠内容物湿质量（P＜0.05）;也能升高盲肠内容物中各SCFAs和总SCFAs含量,且具有明显的剂量关系。结论：薛荔籽果胶对高脂膳食引起高脂血症去势大鼠的血脂、肝脂没有降低效果,反而升高了肝脂水平,但在肠道方面,能改善高脂膳食去势大鼠肠道健康。     

Assessment of probiotic characteristics of lactic acid bacteria isolated from fermented yak milk products of Sikkim,India: Chhurpi,Shyow, and Khachu

The present study documents the probiotic attributes of indigenous lactic acid bacteria (LAB) isolated from local fermented Yak milk products namely Chhurpi, Shyow and Khachu prepared in the northern and eastern region of Sikkim in the Himalayas. Samples were collected aseptically and a total of 170 LAB was isolated and screened for putative probiotic properties like hypocholesteromic effect, acid tolerance, bile tolerance, bile salt hydrolase (BSH) activity and cell surface hydrophobicity. It was observed that 70 LAB isolates showed cholesterol lowering activity, out of which 35 isolates were selected that showed 50% and less cholesterol reducing effect in vitro. Acid tolerance test revealed good tolerance of 12 isolates at pH 2.5 and pH 2.0 for up to 2 hours. The tolerance to 0.5% and 1% of three bile salts acid revealed more growth in MRS broth containing taurocholic acid with the isolates revealing good BSH activity leading to bile acid deconjugation. The cell surface hydrophobicity ranged from 20–95%. Furthermore, 16S rRNA gene sequencing revealed Lactobacillus plantarum YD5S and YD9S, L. pentosus YD8S, L. paraplantarum YD11S, Enterococcus lactis YHC20 and E. faecium YY1 as the best isolates with technological properties. The isolates may serve as potential probiotic candidates with potential for hypocholesteromic benefits in the future.     

An Improved Method of Microencapsulation of Probiotic Bacteria for Their Stability in Acidic and Bile Conditions during Storage

ABSTRACT: The purpose of this study was to develop a method for applying an extra coating of palm oil and poly‐L‐lysine (POPL) to alginate (ALG) microcapsules to enhance the survival of probiotic bacteria. Eight strains of probiotic bacteria including Lactobacillus rhamnosus, Bifidobacterium longum, L. salivarius, L. plantarum, L. acidophilus, L. paracasei, B. lactis type Bl‐O4, and B. lactis type Bi‐07 were encapsulated using alginate alone or alginate with POPL. Electron microscopy was used to measure the size of the microcapsules and to determine their surface texture. To assess if the addition of POPL improved the viability of probiotic bacteria in acidic conditions, both ALG and POPL microcapsules were inoculated into pH 2.0 MRS broths and their viability was assessed over a 2‐h incubation period. Two bile salts including oxgall bile salt and taurocholic acid were used to test the bile tolerance of probiotic bacteria entrapped in ALG and POPL microcapsules. To assess the porosity and the ability of the microcapsule to hold small molecules in an aqueous environment a water‐soluble fluorescent dye, 6‐carboxyflourescin (6 FAM), was encapsulated and its release was monitored using a UV spectrophotometer. The results indicated that coating the microcapsules with POPL increased the overall size of the capsules by an average of 3 μm ± 0.67. However, microcapsules with added POPL had a much smoother surface texture when examined under an electron microscope. The results also indicated that the addition of POPL to microcapsules improved the average viability of probiotic bacteria by > 1 log CFU/mL when compared to ALG microcapsules at 2 h of exposure to acidic conditions. However, similar plate counts were observed between ALG and POPL microcapsules when exposed to bile salts. This suggests that an extra coating of POPL could be readily broken down by bile salts that are commonly found in the lower gastrointestinal tract (GIT). Upon testing the porosity of the microcapsules, findings suggest that POPL microcapsules were less porous and hold 52.2% more fluorescent dye over a 6‐wk storage period.     

The probiotic role of Lactobacillus plantarum in reducing risks associated with cardiovascular disease

A novel strain of Lactobacillus plantarum DMDL 9010 (CGMCC No. 5172) was isolated from naturally fermented mustard. The potential cholesterol reduction effects of this strain were investigated using an in vivo model. The results showed that L. plantarum DMDL 9010 at a dose of 10⁹ cells per day significantly reduced (P ≤ 0.05) serum total cholesterol (TC), low‐density lipoprotein cholesterol content (LDL‐C) levels and atherosclerosis index (AI) by 23.03%, 28.00% and 34.03%, respectively, while L. plantarum DMDL 9010 did not exhibit a significant effect on reducing serum triglycerides (TG) and increasing the serum high‐density lipoprotein cholesterol content (HDL‐C) in experimental rats (P > 0.05). The morphological and pathological changes in the liver illustrated that L. plantarum DMDL 9010 protected the rats against hepatocyte steatosis. Additionally, a high dose of L. plantarum DMDL 9010 was shown to exhibit a positive cholesterol‐lowering effect through decreasing the liver cholesterol (?33.20%) and triglyceride (?40.86%) levels, and increasing significantly (P ≤ 0.05) faecal cholesterol (+31.07%) and bile acid excretion (+70.18%). The results demonstrated that L. plantarum DMDL 9010 acted in a dose‐dependent way to decrease serum and total hepatic cholesterol and triglyceride and enhance faecal excretion of bile acids. In conclusion, these findings suggest that L. plantarum DMDL 9010 has potential to be explored as a probiotic for hypercholesterolaemic preventive and therapeutic.     

Multi‐Cereal Beverage Fermented by Lactobacillus Helveticus and Saccharomyces Cerevisiae

A novel multi‐cereal‐based fermented beverage with suitable aroma, flavor, and pH fermented by lactic acid bacteria and Saccharomyces cerevisiae was developed. Twenty‐seven lactobacilli strains were screened for acid production (pH and titratable acidity) in a mixture of malt, rice, and maize substrates. It was found that Lactobacillus helveticus KLDS1.9204 had the greatest acid production among 27 lactobacilli tested. The fermentation performance of L. helveticus KLDS1.9204 was also assayed and the fermentation parameters were optimized using Plackett–Burman design and steepest ascent method. L. helveticus KLDS1.9204 showed good proteolytic capability, however, the strain could not utilize starch. The optimum substrate consisted of 50% malt (25 g/100 mL), 25% rice (20 g/100 mL), and 25% maize (30 g/100 mL). The inoculum was 5% with a ratio of S. cerevisiae to L. helveticus KLDS1.9204 of 2.5:1. The optimum temperature was 37 °C and the time was 22 h. Lastly, the quality of the multi‐cereal‐based fermented beverage was evaluated. This beverage was light yellow, transparent, and it tasted well with a pleasant acid and a unique flavor of cereals. The beverage was rich in free amino acids and organic acids. The pH and titratable acidity of the beverage were 3.5 and 29.86 °T, respectively. The soluble solids content of the beverage was 6.5 °Brix, and the alcohol content was 0.67%.     

A bile salt hydrolase gene of Lactobacillus plantarum BBE7 with high cholesterol-removing activity

Sixteen Lactobacillus strains were screened using a plate agar containing glycodeoxycholic acid or taurodeoxycholic acid and quantitative BSH assay method, along with cholesterol-removing properties in vitro. Most BSH-positive strains tested were more efficient in hydrolyzing glycoconjugated bile salts than tauroconjugated bile salts. Among these strains, Lactobacillus plantarum isolate BBE7 had a relatively high BSH activity toward both bile salts and a higher cholesterol-removing activity (about 72.8?%) from cholesterol (100???g/mL)-containing MRS culture, as compared with other tested strains. The bsh gene of this strain composed of about 43?kDa protein was cloned, sequenced, and overexpressed in Escherichia coli BL21 (DE3). The bsh gene contained a single ORF of 975 nucleotides flanked by a methionine start codon and translational termination codon and encoded a 324-amino-acid protein.