Antifungal,Mechanical, and Physical Properties of Edible Film Containing Williopsis saturnus var. saturnus Antagonistic Yeast

The molding of food products causing health risks is a main problem in the food industry. In this study, as an alternative solution for preventing mold growth, an antifungal edible film was developed by incorporating Williopsis saturnus var. saturnus (0; 3; 7; and 9 logs CFU/cm²) into whey protein concentrate (WPC) based films. Antifungal properties of the films against Penicilium expansum and Aspergillus niger were analyzed using the disc diffusion method. Physical (barrier, solubility, color), mechanical (tensile strength and percent elongation) properties of the films as well as the survival of W. saturnus in the film were assessed during 28 days of storage at 23 °C. According to the results, the viability of W. saturnus (7 and 9 logs CFU/cm²) in WPC films stored for 28 days under vacuum or non‐vacuum decreased to 36% and 60%, respectively. In addition, films containing W. saturnus decreased the viability of P. expansum and A. niger by 29% and 19%, respectively. Adding yeast did not change the tensile strength (P > 0.05), but significantly decreased % elongation and increased water vapor and oxygen permeability and water solubility (P < 0.05). In conclusion, this study showed that the developed films may be useful for inhibiting mold growth on foods.     

Production of Isoamyl Acetate from Sugar Beet Molasses by Williopsis saturnus var. saturnus

Three strains of Williopsis saturnus var. saturnus were employed for the production of natural isoamyl acetate (the character impact compound of banana flavour) using sugar beet molasses as the carbon source and batch cultivation at 25°C under anaerobic conditions. Of the three strains, strain HUT 7087 was the best producer of isoamyl acetate, producing 20.7 mg/L. Sugar beet molasses was deemed to be an acceptable carbon source for the production of this flavour compound.     

Cloning and characterization of WMSU1, a Williopsis saturnus var. mrakii gene encoding a new yeast SUN protein involved in the cell wall structure

SUN proteins of Saccharomyces cerevisiae have been defined on the basis of high homologies in their C-terminal domain. Recently, two of these four proteins were shown to be involved in cell wall morphogenesis (Mouassite et al., 2000a). In the present study, we have isolated WMSU1 (Accession No. AF418983), a new SUN-related gene, from W. saturnus var. mrakii MUCL 41968. Sequencing of the gene revealed an open reading frame coding for 402 amino acids. The predicted amino acid sequence of WMSU1 is closely related to the S. cerevisiae SUN proteins and to other yeast proteins involved in cell wall metabolism. WMSU1 is proposed to encode a cell wall protein since its predicted product contains a signal sequence, a Kex2p cleavage site and a serine/threonine-rich N-terminal domain. Southern blot analysis of the W. saturnus var. mrakii MUCL 41968 genome using the highly conserved domain of WMSU1 as a probe suggested that the isolated gene belongs to a multigenic family. Expression of WMSU1 in E. coli led to a 45 kDa protein, which appeared to be toxic to this host. Scanning electron microscopy analysis of a recombinant S. cerevisiae producing Wmsu1p showed that this strain exhibited an altered cell wall, thus pointing to a probable role of this protein in the cell wall structure.     

Growth and fermentation kinetics of a mixed culture of Saccharomyces cerevisiae var. bayanus and Williopsis saturnus var. saturnus at different ratios in longan juice (Dimocarpus longan Lour.)

Cofermentation of longan juice by mixed cultures of Saccharomyces cerevisiae var. bayanus EC‐1118 and Williopsis saturnus var. saturnus CBS254 at two inoculation ratios (EC‐1118:CBS254 = 1:100 and 1:1000 cfu mL^?1) was performed to ascertain their impact on longan wine aroma compound formation. The results showed improved aroma compound profiles in the longan wine fermented with mixed yeasts in comparison with the longan wines fermented with single yeasts in terms of increased production of acetate esters, fatty acid ethyl esters, alcohols and carboxylic acids. The impact of cofermentation on longan wine aroma formation was affected by the ratio of S. cerevisiae EC‐1118 to W. saturnus CBS254 with 1:100 cfu mL^?1 being more effective. This research suggests that the inoculation ratio of mixed yeasts may be used as an effective means of manipulating longan wine aroma.     

Effect of 1-Methylcyclopropene Treatment and Edible Coatings on the Quality of Minimally Processed Lettuce

ABSTRACT: The effects of 1-methylcyclopropene (1-MCP) and alginate-based edible coatings on the rate of respiration, C2H4 production, color, texture, and total ascorbic-acid level of minimally processed and stored Baby Butterhead lettuce were determined. Samples were stored at 2 °C and 6 °C for 12 d. It was observed that the 1-MCP-treated lettuce had the lowest respiration and ethylene production rates. Russet spotting on the midribs of the leaves in 1-MCP-treated lettuce was the most retarded, and the total ascorbic acid level was the highest. Alginate treatment of lettuce had the most pronounced effect on crispness. Overall, the 1-MCP-treated lettuce had the best quality, followed by the alginate-coated and the control lettuce.     

食用涂膜对油饼含油量和油脂渗透的影响及机理分析

降低含油量是油炸食品健康发展的保证。本研究探讨了甲基纤维素(MC)和大豆分离蛋白(SPI)两种不同种类涂膜物质对油饼含油量和抑油率的影响;通过扫描电镜(SEM)和苏丹红染色后光学显微镜(OM)观察研究MC涂膜对油脂渗透和迁移的影响,并探究MC涂膜降低含油量的机理;通过色差仪和TPA研究了涂膜对油饼感官品质的影响。结果表明:与对照组相比,两种涂膜均能显著降低油饼含油量(p0.05),MC涂膜抑油效果优于SPI,当MC浓度为1%时抑油效果最佳,抑油率为53.77%;表面油和内部油分别降低58.66%和45.43%;通过微观结构分析发现涂膜能够使得油饼表面光滑,减少孔洞,同时能显著降低其渗透深度。这表明,涂膜可以有效降低油饼含油量,使得油饼表面结构致密,抑制油脂的渗透和迁移;且研究表明MC涂膜对样品油炸后色泽及质构影响较小,为进一步生产低油高品质油饼奠定理论基础和技术指导。     

Edible Active Coatings Based on Pectin,Pullulan, and Chitosan Increase Quality and Shelf Life of Strawberries (Fragaria ananassa)

Edible active coatings (EACs) based on pectin, pullulan, and chitosan incorporated with sodium benzoate and potassium sorbate were employed to improve the quality and shelf life of strawberries. Fruits were washed, disinfected, coated by dipping, packed, and stored at 4 °C for 15 d. Application of EACs reduced (P < 0.05) weight loss and fruit softening and delayed alteration of color (redness) and total soluble solids content. In contrast, pH and titratable acidity were not affected (P > 0.05) throughout storage, and ascorbic acid content was maintained in pectin‐EAC coated strawberries. Microbiological analyses showed that application of EACs reduced (P < 0.05) microbial growth (total aerobic counts, molds, and yeasts) on strawberries. Chitosan‐EAC coated strawberries presented the best results in microbial growth assays. Sensory quality (color, flavor, texture, and acceptance) improved and decay rate decreased (P < 0.05) in pectin‐EAC, pullulan‐EAC, and chitosan‐EAC coated strawberries. In conclusion, EACs based on polysaccharides improved the physicochemical, microbiological, and sensory characteristics, increasing the shelf life of strawberries from 6 (control) to 15 d (coated fruits).     

Effect of Edible Coating Process and Irradiation Treatment of Strawberry fragaria spp. on Storage-keeping Quality

ABSTRACT: Gamma-irradiation and various edible coatings were tested on fresh strawberries ( Fragaria spp. ) for keeping fruit quality and extending shelf life. Four coatings based on milk protein were evaluated. In 1 experiment, coating formulation based on caseinate and/or strawberries were irradiated using a ⁶⁰Co source. Both gamma-irradiation treatment and edible coating process significantly delayed (p ≤ 0.05) molds growth. Edible coating based on irradiated caseinate was more effective than that of unirradiated caseinate. In a 2nd experiment, 3 irradiated coatings based on calcium caseinate and whey proteins were evaluated. The coating formulation based on 1:1 caseinate-whey was found to be more effective than those based on calcium caseinate. Addition of calcium chloride or a mixture of pectin and agar increased the effectiveness of the coating by delaying molds' apparition.     

凤尾兰提取物的抑菌活性及其对蒜薹腐烂的抑制作用

灰葡萄孢和葱腐葡萄孢引起的蒜薹灰霉病是导致蒜薹贮期腐烂的主要病因之一。采用滤纸片扩散法研究了凤尾兰提取液对蒜薹灰葡萄孢和葱腐葡萄孢的抑制作用,用二倍稀释法确定提取液的最小抑菌浓度;在常温条件下贮藏,探讨不同浓度的凤尾兰提取物对蒜薹灰葡萄孢和葱腐葡萄孢引起腐烂的抑制作用。结果表明,凤尾兰提取液对灰葡萄孢和葱腐葡萄孢均有较明显的抑制作用,对两种菌的最小抑菌浓度分别为0.062 5 g/mL和0.125 g/mL。凤尾兰提取物对灰葡萄孢和葱腐葡萄孢引起的蒜薹腐烂具有较好的抑制、治疗作用,2.5 g/L、5 g/L、10 g/L的凤尾兰提取物均能有效抑制蒜薹灰葡萄孢和葱腐葡萄孢的侵染,减少蒜薹腐烂,其中以10 g/L的处理效果最佳。     

微波处理对枯草杆菌芽孢致死效果研究

通过比较不同温度和时间下微波和水浴对枯草杆菌黑色变种芽孢的致死效果,以探讨微波杀菌的热效应与非热效应。枯草杆菌黑色变种芽孢活化后,制成104CFU/mL 的孢子悬浮液,然后分别用微波和水浴加热对芽孢进行灭菌,最后测定灭菌后的单位体积菌落总数,计算致死率。结果表明,微波和水浴加热在92℃时的致死率都高于85℃时的致死率。在相同的温度和时间下,微波的杀菌效果好于水浴加热,存在非热效应。只有在92℃,20min 时,微波和水浴加热对芽孢的致死率差异不显著,非热效应不明显。     

黄桃水溶性多糖的抗肿瘤作用及清除自由基、提高免疫活性研究

从黄桃果肉中提取出两种水溶性多糖HTP1和HTP2,本文研究了HTP1和HTP2对自由基的清除作用,以及以小鼠为动物模型研究了它们在抗肿瘤及提高免疫力方面的功效,实验结果表明,HTP1和HTP2对羟基自由基(·OH)均有显著的清除作用,其IC50分别为270.92μg/ml和4.361mg/ml。HTP1对超氧阴离子自由基(O2)有明显清除作用,其IC50约为401.3μg/ml,而HTP2无清除超氧阴离子自由基(O2)的能力。HTP1及HTP2各分别为100mg/kg、200mg/kg剂量ip×10qd方案,对小鼠Lewis肺癌足趾皮下接种的抑瘤率分别为54.69%、43.44%及47.08%、44.48%。对荷Lewis肺癌小鼠的NK及淋巴细胞转化的活性,HTP1和HTP2两个剂量组成均有较明显的促进和提高。     

不同光强LED黄光对滇重楼生长、光合特性和皂苷含量的影响

为探究发光二极管(LED)黄光不同光强对滇重楼光生物学特性和品质的影响,同时为LED光源在滇重楼生产上的应用提供理论依据。本研究以3年生滇重楼种苗为试验材料,采用波长为590 nm±5 nm的黄光为照射光源,设置了25、50、75、100μmol/(m~2·s)4个光强梯度处理,对滇重楼生物学鲜重、叶片光合荧光特性及根茎皂苷含量进行了研究。结果表明,75μmol/(m~2·s)处理滇重楼叶片净光合速率、荧光指标、气孔导度、蒸腾速率均为最高。25μmol/(m~2·s)处理的荧光指标最低。100μmol/(m~2·s)处理下重楼根茎皂苷含量最高,25μmol/(m~2·s)处理下皂苷含量最低。综合分析滇重楼叶片光合荧光特性和根茎皂苷含量,黄光75μmol/(m~2·s)对促进滇重楼叶片的光合作用最有利,黄光100μmol/(m~2·s)对增加滇重楼根茎皂苷含量最有利。建议在滇重楼栽培上将黄光光强控制在75~100μmol/(m~2·s)为宜。     

拟氨基多糖抑菌剂K1、K2对烟草黑胫病原菌(Phytophthora parasitica var.nicotianae)的抑制效果研究

采用生长速率法测定了拟氨基多糖类抑菌剂K1、K2对烟草黑胫病原菌(Phytophthora parasitica var.nicotianae)的抑菌效果。结果表明:K1、K2对烟草黑胫病原菌均有显著的抑制作用,且抑制效果随K1、K2浓度的增大而增强;20 mL/L的K1、K2对烟草黑胫病原菌的抑制率分别为50.58%、84.68%,EC50分别为26.15、4.87 mL/L。     

果色和成熟度对樱桃番茄(Solanum lycopersicum var.cerasiforme)果实挥发物分布的影响

为探究果色和成熟度对樱桃番茄果实挥发物的影响,用顶空固相微萃取-气相色谱-质谱联用法测定育种自交系材料金珠(橙)、黑樱桃1(紫)、1号(粉)、红珍珠(红)在绿熟期、转色期和红熟期的挥发物.分析发现,橙色番茄挥发物明显高于红色和粉色番茄.橙色番茄在绿熟期,紫色番茄在转色期和红熟期挥发物最高,而粉色番茄挥发物始终最低.气味...     

薇菜天然复配保鲜剂配方的优化及其对薇菜贮藏期生理指标的影响

为了保持薇菜的品质,延长其货架期,本实验以薇菜为研究对象,在单因素实验的基础上采用L₉(3⁴)正交试验考察三种天然保鲜剂茶多酚、川陈皮素、壳聚糖复配对薇菜感官品质、叶绿素含量、V_C含量的影响。结果表明,筛选出的复合保鲜剂配方为茶多酚0.8 g/L、川陈皮素2.5 g/L、壳聚糖2 g/L。与不添加保鲜剂的薇菜相比,该配方对于能够提升薇菜的感官品质,维持薇菜的叶绿素、V_C、可溶性糖含量,对多酚氧化酶(PPO)、过氧化物酶(POD)的活性具有抑制作用,在4 ℃条件下较未用保鲜剂处理的薇菜能延长5~7 d贮藏时间。     

药食同源代代花药理作用及应用研究进展

代代花是药食同源目录公布的第一批中药材,含有挥发油类、黄酮类、多糖类、生物碱类、香豆素类等化学成分,具有抗氧化、抗炎、抗菌、抗病毒、抗肿瘤、降血脂等药理作用,在食品、医药、日化等行业有一定应用。作为保健产品组分或中药配方组分,其可起调节机体功能或治疗病症的作用,在大健康领域彰显独特的价值。近年来,代代花的关注度进一步提升,针对其药理作用及应用方面的研究逐渐增加。该研究系统梳理国内外相关研究,从代代花的药理作用以及应用现状等方面进行分析和总结,期望推进深入研究和开发代代花的发展进程,为未来研究和综合开发利用代代花提供理论依据。     

外源硒对茎瘤芥硒形态及硒吸收的影响

采用大田实验研究叶面喷施硒(0.0、1.0、2.5 mg/L)对茎瘤芥生长、硒形态、硒吸收和转化的影响。结果表明,叶面喷施1.0 mg/L的硒提高了茎瘤芥的产量,但未达到显著水平(P0.05)。叶面喷硒降低了茎瘤芥硝酸盐含量,在一定程度上增加了茎瘤芥游离氨基酸、VC、还原糖的含量,分别较对照增加了40.41%、13.36%和46.73%。叶面喷施硒后茎瘤芥中全硒和有机硒含量分别较对照增加了46.1%~193.9%和74.0%~271.5%,并且随外源硒质量浓度的升高而显著增加。随硒质量浓度的增加,茎瘤芥有机硒转化率显著提高,1.0、2.5 mg/L硒处理分别较对照增加了19.33%和23.57%。茎瘤芥吸收的硒主要以有机硒的形式存在,茎瘤芥全硒和有机硒含量与外源硒质量浓度呈极显著正相关(P0.01)。