Optimising germinated conditions to enhance yield of resveratrol content in peanut sprout using response surface methodology

Peanut sprout has associated with enhance the content of a nonflavonoids known as resveratrol, which influences a variety of functions including against cancer, cardiovascular and delaying ageing. Peanut from Liaoning province of China was used as a material to accumulate resveratrol during germination. The individual effects of soaking temperature and time as well as germination temperature, time and humidity on resveratrol accumulation in 5 days germinated peanut were investigated. Then, based on Box–Behnken design, interactive effects of the germination parameters were evaluated by response surface methodology. The optimum conditions were as follows: soaking temperature at 35 °C, soaking time at 8 h, germination temperature at 29 °C, germination humidity at 90%, and germination time at 5 day. Under the optimum condition, resveratrol content reached 32.87 μg g^?1, which was almost 9.78 times higher than that in the peanut which did not germinate.     

不同抗氧化剂对米糠油抗氧化性能影响的研究

试验研究了在(63±1)℃加速氧化条件下,以过氧化值(POV)作为评价指标,TBHQ、BHT、PG、柠檬酸及复配抗氧化剂对米糠油抗氧化性能的影响.结果表明,复配氧化剂的抗氧化效果优于单一抗氧化剂,柠檬酸对酶抗氧化剂有协同增效作用,精制米糠油中添加0.015%TBHQ+0.005%PG和0.01%柠檬酸的抗氧化效果最好,是不加抗氧化剂的米糠油的抗氧化效果的9倍.     

添加白酒对人工接种东北酸菜挥发性风味成分及感官特性的影响

该实验研究了添加白酒对人工接种乳酸菌发酵东北酸菜理化、挥发性风味成分及感官特性的影响。首先通过乙醇胁迫及产酸能力测定筛选混菌发酵剂,采用顶空固相微萃取（HS-SPME）结合气相色谱-质谱联用（GC-MS）分析酸菜的挥发性风味成分,并结合感官评分与电子舌鉴定白酒对酸菜感官特性的影响。结果表明,植物乳杆菌（Lactobacillus plantarum）、干酪乳杆菌（Lactobacillus casei）和柠檬明串珠菌（Leuconostoc citreum）3株乳酸菌对乙醇具有一定耐受性且产酸能力较强。添加2%白酒结合3株乳酸菌混菌发酵酸菜的可滴定酸含量较未添加白酒的混菌发酵酸菜降低了4.02%。此外,添加白酒接种发酵酸菜形成了以酯类、酮类、含硫化合物和氨基酸为主的风味结构,并且提高了鲜味,降低了苦涩味,在颜色、味道和口感上均具有显著优势。为实现人工接种东北酸菜的品质提升提供理论基础。     

一种简单长期保藏乳酸菌菌种方法的研究

为了适应发酵蔬菜生产企业菌种保藏,本试验探讨乳酸菌培养基质的灭菌时间,并在单因素试验基础上,采用响应面法优化改良MRS培养基配方。结果表明,乳酸菌培养基质白菜帮颗粒灭菌时间为9 min,改良MRS培养基最佳配方为：白菜帮颗粒25 g/L、蛋白胨9 g/L、牛肉膏8 g/L、葡萄糖14 g/L、柠檬酸三铵2 g/L、酵母膏5 g/L、乙酸钠2 g/L、K2HPO4 2 g/L、MgSO4·7H2O 0.58 g/L、MnSO4·4H2O 0.25 g/L。在优化培养基条件下,副干酪乳杆菌的菌数为1.19×1010 CFU/mL。1～4 ℃冷藏可保藏3～4年,-16～-20 ℃冷冻可保藏4～5年。此保藏方法操作简单、成本低,菌种质量稳定可靠,适合蔬菜发酵企业保藏生产用乳酸菌菌种。     

副溶血性弧菌毒力因子及耐药机制研究进展

副溶血性弧菌是水产品中主要的致病菌之一,既可造成养殖水产品的疾病与死亡,也可引起人类的胃肠炎等疾病,不仅具有潜在的食品安全隐患,也对消费者健康造成潜在危害。该文主要阐述了副溶血性弧菌的毒力因子耐热直接溶血素(thermostable direct hemolysin, TDH)以及分泌系统T3SS1、T3SS2在菌株体内的作用机理,并对副溶血性弧菌产生耐药性的5种机制——产生生物被膜、质粒介导耐药、产生灭活酶或钝化酶类、外排泵主动排出抗菌药物、药物靶点发生改变进行了综述。     

梨花营养成分及特性分析

目的分析评价梨花的营养成分。方法按照食品安全国家标准中测定营养成分的规定,测定梨花中的蛋白质、碳水化合物、矿物质、维生素等营养成分;利用乙醇回流提取, NaNO_2-Al(NO_3)_3-NaOH显色法测定总黄酮含量;利用石油醚回流提取, Liebennann-Burchard显色法测定总甾体含量。结果梨花含有丰富的蛋白质、碳水化合物、矿物质、维生素等营养成分。尤其是矿物质K(151.97 mg/100 g)、VC(3.117 mg/100 g)、赖氨酸(130.45 mg/100 g)以及黄铜(1.055 g/100 g)和甾体类化合物(0.041 g/100 g)等生物活性物质含量较多。结论梨花是富含营养物质的理想天然保健食品。     

Optimising water activity for storage of high lipid and high protein infant formula milk powder using multivariate analysis

High lipid and high protein infant formula milk powders were stored at water activity of 0.11, 0.33 and 0.53 for up to fourteen weeks at 40 °C to investigate the effect of storage water activity on physicochemical properties and formation of volatiles to thereby recommend optimal storage water activity conditions. Water activity of the powders was determined during storage together with surface colour, glass transition temperature combined with dynamic headspace sampling followed by gas chromatography/mass spectrometry. The principal component analysis (PCA) showed that the optimal water activity for storage of high lipid infant formula milk powder, for which lipid oxidation was found to be the critical quality parameter, is a_w = 0.33 with lowest lipid oxidation, while for high protein infant formula milk powder, for which protein degradation was found to be the critical quality parameter, a_w = 0.11 is optimal to limit formation of Maillard reaction products.     

适于万寿菊鲜花发酵的优良乳酸菌菌株筛选研究

筛选出3种适宜万寿菊鲜花发酵的优良乳酸菌菌株为植物乳杆菌、赖氏乳杆菌、嗜热链球菌。发酵万寿菊颜色、质地、气味良好。     

冬枣变温压差膨化干燥工艺研究

以冬枣为原料,采用变温压差膨化干燥技术,探讨了预干燥时间、抽空时间、膨化温度、抽空温度、停滞时间和膨化压力对冬枣膨化产品硬度、脆度、色泽和水分含量的影响。结果表明:膨化温度、抽空温度和抽空时间是影响产品膨化质量的关键因素;冬枣预干燥6h后,膨化温度85℃,抽空温度60℃,抽空时间2h为较适合工艺参数;停滞时间和膨化压力差在一定范围内对膨化产品的质量影响不大,实验确定停滞时间15min,膨化压力差0.2MPa为较适合工艺参数。     

Purification of novel bacteriocin produced by Lactobacillus coryniformis MXJ 32 for inhibiting bacterial foodborne pathogens including antibiotic-resistant microorganisms

Bacteriocins produced by LAB comprise a variety of antimicrobial proteins or peptides which can be used as food biopreservatives and/or possible antibiotic alternatives. Bacteriocin-producing Lactobacillus coryniformis MXJ 32, which was identified based on its 16S rRNA gene sequence, was isolated from a traditional fermented vegetable (Jiangshui Cai) of Xixiang county, Shaanxi province, China. Thereafter bacteriocin (designated as lactocin MXJ 32A) produced by L. coryniformis MXJ 32 was purified by ammonium sulfate precipitation, dialysis and ion exchange chromatography. The molecular mass of lactocin MXJ 32A was 3520 Da determined by LC-ESI/MS and the N-terminal sequence of lactocin MXJ 32A was NH₂-GEPGPMGPAGAD. Lactocin MXJ 32A had a broad antimicrobial spectrum including many Gram-positive and Gram-negative foodborne pathogens, in which even some antibiotic-resistant foodborne pathogenic strains could also be inhibited. The MIC of lactocin MXJ 32A for Staphylococcus aureus and Escherichia coli was 10 mg/mL. Lactocin MXJ 32A showed good pH-stability and heat stability and was sensitive to proteolytic enzymes. It was shown by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) that the possible mode of action of lactocin MXJ 32A was pore formation of the cytoplasmic membrane of target cells.