鱼油风味酸奶的开发及稳定性评价

以全脂奶粉、鱼油、白砂糖为主要原料,以保加利亚乳杆菌和嗜热链球菌为发酵菌种制作鱼油风味酸奶,进行鱼油风味酸奶配方研究与产品稳定性评价。通过感官评定确定最佳酸奶配方为奶粉添加量10%,鱼油添加量0.15%,白砂糖添加量8%。核磁共振与显微观察结果表明,鱼油添加后未对酸奶水分分布产生影响,鱼油在酸奶中呈均匀分布。电子鼻分析结果表明,与原味酸奶相比,鱼油风味酸奶风味更为融合,更接近原味商业酸奶。以储存期pH、酸度、流变特性、感官评价为指标对鱼油风味酸奶进行了稳定性评价,结果表明鱼油风味酸奶在储存期内可保持良好的稳定性,鱼油的添加可有效避免酸奶的过度酸化,使酸奶保持良好的口感。     

Effect of different levels of fat and inulin on the microbial growth and metabolites in probiotic yogurt containing nonviable bacteria

Effects of different levels of fat and inulin on bacterial cell counts, degree of proteolysis and concentrations of organic acids in the yogurt containing inactivated cells of probiotic strains Bifidobacterium animalis and Lactobacillus acidophilus were investigated. Results showed that both L. acidophilus and B. animalis grew well in the yogurt samples reaching cell counts higher than 10⁶ CFU mL^?1 at the final pH of 4.5. Inulin at the concentration of 1% had no significant effects on the production of organic acids and cell counts of L. acidophilus, but promoted the growth of B. animalis with a reduction in the degree of proteolysis. Generally, different fat levels showed significant effects on the production of organic acids and nonsignificant effects on the cell counts of probiotic bacteria and degree of proteolysis. In case of lactic acid, the ratio of L‐ (+)to D‐ (?) isomer ranged from 50/50 to 80/20 in yogurt samples.     

Physical,chemical, microbial,and sensory evaluation and fatty acid profiling of value-added drinking yogurt (laban) under various storage conditions

Yogurt is defined as a coagulated milk product obtained from the fermentation of lactose into lactic acid. Drinking yogurt (laban) was prepared from buffalo milk, cow milk, and a 50:50 blend (cow + buffalo milks) by adding 0.5% carboxymethyl cellulose to each of the 3 milk treatments. Samples were then refrigerated for 7, 14, and 21 d before determination of physical, microbial, and sensory parameters. Yogurt prepared from buffalo milk had higher fat and protein contents, and better taste, aroma, and overall consumer acceptability compared with laban prepared from cow milk or mixed milk. During storage, protein and total solids contents remained unchanged, whereas milk fat, color, appearance, taste, smell, texture, and overall acceptability of laban decreased in the different treatment groups. The acidity of laban increased with storage time. Bacteria, including coliforms, were not found in any treatment group during storage. In conclusion, overall acceptability of laban prepared from buffalo milk was higher than that made from cow milk or mixed milk, but increased storage time reduced the quality of laban prepared from cow, buffalo, or mixed milk.     

Survival of Escherichia coli O157:H7 in yogurt drink, plain yogurt and salted (tuzlu) yogurt: Effects of storage time, temperature, background flora and product characteristics

The survival of Escherichia coli O157:H7 at 4 and 22°C in yogurt drink, plain yogurt and salted yogurt (yogurt native to Hatay, Turkey) was studied. Total aerobic plate count (TPC), total mould and yeast count, pH and titratable acidity during the storage period were measured. pH and TPC count of the samples at 22°C were significantly higher than those of samples at 4°C ( P <  0.01). E. coli O157:H7 survived in the products at both 4 and 22°C, whereas survival of E. coli O157:H7 was significantly lower at 4°C than at 22°C ( P <  0.05). Multiple linear regression models were used to determine factors affecting the survival of E. coli O157:H7.     

Calcium alginate‐resistant starch mixed gel improved the survival of Bifidobacterium animalis subsp. lactis Bb12 and Lactobacillus rhamnosus LBRE‐LSAS in yogurt and simulated gastrointestinal conditions

The aim of this study was to investigate the protective effect of microencapsulation in calcium alginate‐resistant starch mixed gel of a new human isolated strain of Lactobacillus rhamnosus LBRE‐LSAS compared with the probiotic strain of Bifidobacterium animalis subsp. lactis Bb12. Influence of microencapsulation was tested under deleterious digestive environment, when challenged to salivary α‐amylase, to simulated gastric fluid and to simulated intestinal fluid. Bacterial survival, post‐acidifying activity and exopolysaccharides (EPS) content in stored mix yogurt were assessed. Integrity of the beads was acceptable under α‐amylase levels largely higher than those found in human saliva. Under simulated gastrointestinal model, viable cell counts of encapsulated cells were significantly higher than those observed with free cells and remained at the recommended levels. Additionally, microencapsulation allowed an improved viability of bacteria and generated higher EPS amounts in mix yogurt stored at 4 °C. Our results indicate that calcium alginate‐resistant starch beads extend survival under digestive conditions and in yogurt and could be used as an efficient delivery system for probiotics.     

Development and characterization of black mulberry (Morus nigra) pekmez (molasses) composite films based on alginate and pectin

Production of composite films is an important approach to improve functionality of edible films, by combining different polysaccharides, proteins, and lipids. Carbohydrate-based composite films are most attractive, which have good film-forming ability due to their unique colloidal properties. Fruit purees include high polysaccharide content that plays a role to have desirable film properties including mechanical resistance, efficient barrier properties, and selective permeability against oxygen transmission. The purpose of this study was to characterize physical, barrier, mechanical, thermal, and water sorption properties of composite films formulated with different mulberry pekmez concentrations (26, 32, and 38 °Brix) based on alginate or pectin. All film-forming solutions were showed shear thinning behavior with higher yield stress and viscosity-shear rate data were fitted to Ostwald de Waele model (R² ≥ 0.943). A noticeable decrease in tensile strength of films with increasing concentration was determined, but films prepared with high concentration showed more flexible. The mechanical properties of pectin films exhibited weakened properties compared to alginate films. Increasing pekmez concentration in the film matrix improved the water vapor permeability of alginate films, whereas pectin films showed reverse behavior as resulting in cracks and crack propagation within the structure. The sorption isotherms of films showed a typical profile of foods contain high soluble components and the Guggenheim–Anderson–deBoer (GAB) model gave a good fit for all of the obtained data. The results showed that mulberry pekmez films based alginate have a potential for food applications depends on the physical properties and for the replacement of non-biodegradable plastic packaging.     

海藻酸钠和低甲氧基果胶抑制油炸甘薯淀粉吸油效果及结构变化（网络首发、推荐阅读）

为探明海藻酸钠（sodium alginate,AG）和低甲氧基果胶（low methoxyl pectin,LMP）对油炸甘薯淀粉吸油率的影响,使用低场核磁共振仪、激光共聚焦显微镜、X射线衍射仪、红外光谱及差示扫描量热仪分别分析了添加0.5%（w/w）、2%（w/w）AG和2%（w/w）LMP的油炸甘薯淀粉的油含量及其分布、热性质等。结果表明,添加AG或LMP可以显著降低油炸甘薯淀粉总油含量,油主要分布在淀粉颗粒表层,淀粉结晶类型由A+V型变为V型,糊化焓和相对结晶度明显降低。与添加LMP的油炸甘薯淀粉相比,添加AG后总油含量、相对结晶度和糊化焓更低。添加AG质量分数为2%时,油炸甘薯淀粉糊化程度最高,淀粉颗粒表层呈连续、致密结构,总油含量和表层油含量均为最低。可为健康、低脂油炸淀粉类食品加工提供参考。     

Phenolic constituents of cell wall types of normal and brown midrib mutants of pearl millet (Pennisetum glaucum (L) R Br) in relation to wall biodegradability

The cell walls of parenchyma, rind and vascular bundle fractions of pearl millet (Pennisetum glaucum (L) R Br) were isolated from two brown midrib mutants (bmr) 5753 and 5778 and from their normal (N) near-isogenic line. The cell wall content of parenchyma was lower than that of vascular bundle which, in turn, was lower than that of rind. The amounts of ferulic and p-coumaric acids released by NaOH treatment of the cell walls were in the ranges 3-7 mg g^?1 and 2-26 mg g^?1, respectively. Parenchyma cell walls of the N line had the highest content of p-coumaric acid (26 mg g^?1). This content of p-coumaric acid in the N line contrasts with that of bmr 5753 parenchyma (2 mg acid g^?1 walls) and bmr 5778 (7 mg acid g^?1 walls). The concentration of p-coumaric acid was highest in parenchyma cell walls that had been found to be the least digested. Parenchyma, rind and vascular bundle cells walls of the N line had much higher ratios of p-coumaric acid to ferulic acid than the mutants; rind and vascular bundle walls were less digestible than parenchyma. Small amounts of truxillic acid dimers were released by NaOH from the parenchyma walls of bmr 5778. Treatment of parenchyma, rind and vascular bundle cells walls with purified ‘driselase’ (containing xylanases and cellulases) released p-coumaroyl and feruloyl trisaccharides. Between 25 and 53% of the ferulic acid that was released by the NaOH treatment could be accounted for as feruloyl trisaccharide, but only 1-19% of the p-coumaric acid was accounted for as p-coumaroyl trisaccharide.     

Effect of Film-Forming Gums in the Preservation of Salted and Dried Indian Mackerel (Rastrelliger kanagurta Cuvier)

Curing preservation of fish is the most popular method in the developing countries and India is no exception. Different film-forming gums, namely sodium alginate, tamarind kernel powder, guar gum and agar agar were tried to find their effect in preservation of salted and dried mackerel and in extending the shelf-life of these products. Various biochemical, microbiological and organoleptic parameters were recorded during the storage period. The treatment of salted dried fish with gum solutions and subsequent formation of film upon drying was found to be the best in preserving the quality of salted fish. The effect of film forming gums on the shelf-life of the products was found to be highly significant ( P< 0·05) as compared to the control.     

中国谷子种植历史演变及未来发展方向（网络首发、推荐阅读）

谷子是我国北方旱作农业起源的代表,在距今8 000年左右完成驯化并开始种植,在距今5 000年左右粟作栽培逐步占据粮食生产主导地位,距今2 000年左右达到史前时期的顶峰。夏商周是粟作原始生产技术向传统农业技术过渡时期,牛耕和铁农具出现以及精耕细作栽培技术使春秋战国时期粟作栽培取得突破进展,秦汉时期粟种植区域继续扩大,至魏晋南北朝时期,传统粟作也达到了繁盛阶段。进入隋唐时期,稻、麦地位逐步上升,逐步取代粟的传统地位,但在传统的黄河流域,谷子仍然占据主粮地位。元宋时期,小麦继续向南方传播,粮食生产地位逐步超过谷子。明清时期,为满足急剧增长的人口粮食需求,玉米、甘薯等高产作物种植面积快速扩大,但谷子仍是北方重要的粮食作物。建国以后我国谷子种植面积持续下降,经历了主粮时期、主粮向杂粮过渡时期和杂粮时期三个阶段,主要原因在于单产提升较慢、栽培繁琐、消费需求减少和政策缺失。新时期,谷子具有的营养、生态以及文化属性给谷子产业发展带来新机遇。未来,我国谷子种植面积将稳中有升,优质食用、营养保健、加工专用等特色品种需求成为趋势,加工产品类型将更加丰富,谷子产业逐步向功能化、品牌化、精品化和高端化方向发展。     

Comprehensive molecular,probiotic, and quorum-sensing characterization of anti-listerial lactic acid bacteria,and application as bioprotective in a food (milk) model

Listeria monocytogenes is a major foodborne pathogen that adversely affects the food industry. In this study, 6 anti-listerial lactic acid bacteria (LAB) isolates were screened. These anti-listerial LAB isolates were identified via 16S rRNA gene sequencing and analyzed via repetitive extragenic palindromic-PCR. Probiotic assessment of these isolates, comprising an evaluation of the antibiotic susceptibility, tolerance to lysozyme, simulated gastric and intestinal juices, and gut conditions (low pH, bile salts, and 0.4% phenol), was carried out. Most of the isolates were resistant to streptomycin, vancomycin, gentamycin, kanamycin, and ciprofloxacin. All of the isolates were negative for virulence genes, including agg, ccf, cylA, cylB, cylLL, cylLS, cylM, esp, and gelE, and hemolytic activity. Furthermore, autoinducer-2 (a quorum-sensing molecule) was detected and quantified via HPLC with fluorescence detection after derivatization with 2,3-diaminonaphthalene. Metabolites profiles of the Lactobacillus sakei D.7 and Lactobacillus plantarum I.60 were observed and presented various organic acids linked with antibacterial activity. Moreover, freeze-dried cell-free supernatants from Lb. sakei (55 mg/mL) and Lb. plantarum (40 mg/mL) showed different minimum effective concentration (MEC) against L. monocytogenes in the food model (whole milk). In summary, these anti-listerial LAB isolates do not pose a risk to consumer health, are eco-friendly, and may be promising candidates for future use as bioprotective cultures and new probiotics to control contamination by L. monocytogenes in the food and dairy industries.     

Comparative evaluation of bacterial cellulose (nata) as a cryoprotectant and carrier support during the freeze drying process of probiotic lactic acid bacteria

Nata or bacterial cellulose produced by Acetobacter xylinum was compared for its cryoprotective and carrier support potential for probiotic lactic acid bacteria against other established cryoprotectants like 10% skim milk, calcium alginate encapsulation or 0.85% physiological saline and distilled water. Individual lactic acid bacteria were grown in MRS broth in the presence of nata cubes or the bacterial suspension mixed with either powdered bacterial cellulose (PBC), 10% skim milk, saline or distilled water and freeze dried. These freeze dried cells were stored at temperatures of either 30 °C or 4 °C and periodically checked for viability. The freeze dried cells on carrier supports were directly used to prepare fermented milks to establish the activity of these cultures. Scanning electron microscopy was employed to visualize the support matrix with the attached lactic acid bacteria. The freeze drying process resulted in a 3.0 log cycle reduction in the colony forming units as compared to the original cell suspension in the case of all the lactic acid bacteria. The growth of lactic acid bacteria in the presence of bacterial cellulose (nata) offers a convenient and easy method to preserve bacteria for short durations and use it as a support to carry out other fermentation processes.     

烤烟新品种中烟100(CF965)的选育及其应用评价

中烟100（CF965）是以兼抗烟草多种主要病害的烤烟新品系9201为母本与易感赤星病、对低温短日照反应敏感的优质烤烟品种NC82为回交亲本，通过杂交重组、回交聚合，经系谱法选育而成。试验结果证明：该品种适应性强，耐肥水，易烘烤；抗黑胫病、赤星病，耐气候斑点病；烤后原烟呈浅桔黄色，油分多，色泽均匀鲜亮，主要化学成份含量适宜，比例协调，烟叶质量符合中式卷烟需要；与目前主栽对照品种比较，烟叶产量提高9．44％，均价提高9．24％，中上等烟比例增加3．3个百分点，产值提高18．36％；是一个品质、抗性、产量、适应性等综合性状较能兼顾、适宜全国主要烟区种植的优良烤烟新品种。