Antibacterial mechanism of adzuki bean seed coat polyphenols and their potential application in preservation of fresh raw beef

The monomeric phenolic components of adzuki bean seed coat polyphenols (ABSCPs) were analysed, and their antibacterial activity and mechanism against two tested bacteria (Escherichia coli ATCC8797 and Staphylococcus aureus ATCC12600) were evaluated for their potential application in preservation of fresh raw beef. ABSCP contained 13 kinds of monomeric phenols, and the minimum inhibition concentration (MIC) of ABSCP against E. coli and S. aureus was 1250 and 625 μg ml⁻¹, respectively. The mechanism of ABSCP against E. coli and S. aureus was associated with increased cell protein and nucleic acid leakage, increased cell membrane potential, decreased intracellular ATP concentration and morphological changes in bacterial cell. In addition, ABSCP with whey protein isolate (WPI) was applied to fresh raw beef and this remarkably retarded microbial growth by maintaining the total microbial quality below the acceptable limit of 6 lg CFU g⁻¹ for 14 days. Lower pH and total volatile base nitrogen values were observed in the coated samples during refrigerated storage (4 °C). As a result, we found that ABSCP, as a natural food bacteriostatic agent, can effectively inhibit the growth of E. coli and S. aureus and combined with WPI to apply to fresh raw beef to extend its shelf life.     

镀锌层中Cr6+的测定

研究用光度法测定镀锌层中六价铬的方法,建立了最佳工作条件,进行了干扰试验。结果表明,最大吸收波长位于540 nm处,显色酸度控制在pH=2±0.5,以pH=2时显色最好;当显色剂用量>1.5 mL时,吸光度最大且恒定;浸取温度选择在70℃时,吸光度稳定且最大;吸光度测定选择浸取时间以1 h为宜。Cr6+在0~40μg内符合比尔定律,线性相关系数r=0.999 8。     

Seed coats of pulses as a food ingredient: Characterization,processing, and applications

BackgroundIn recognition of their multiple benefits on environment, food security, and human health, pulses are attracting worldwide attention. The seed coat is a major by-product of pulse processing, and its only markets are as low value ruminant feed and very limited use in high fibre foods. Recently, accumulating studies have suggested that this underutilised by-product has greater potential as a novel natural “nutritious dietary fibre” which can be used as a functional food ingredient.Scope and approachThis review discusses biochemical and physicochemical functionalities of seed coats of six globally important pulses: chickpea, field pea, faba/broad bean, lentil and mung bean with a special emphasis on the emerging food pulse lupin. Food process modification and recent human food applications of the seed coats are summarized. Bio-availability of the seed coat compounds, and phomopsins contaminated lupin seed coats as a typical example of safety issue are discussed.Key findings and conclusionsHigh levels of dietary fibre, minerals and potential health-promoting phytochemicals in the seed coats indicate their great potential to be used as a natural “nutritious dietary fibre”. However, further in-depth studies are required to improve their desirable nutritional, physiological and techno-functional properties whilst minimizing any undesirable ones.     

松仁红衣多酚的提取及体外抗氧化活性研究

利用超声波辅助乙醇溶剂浸提法,从松仁红衣中提取具有抗氧化活性的多酚类物质。通过单因素和正交实验,研究乙醇浓度、提取温度、料液比、超声功率、超声时间对多酚得率的影响,确定了提取多酚的最佳工艺条件:乙醇浓度60%、提取温度60℃、料液比1∶20(g/m L)、超声时间90min、超声功率300W,此条件下所得提取液的多酚得率为2.36%。并进行了松仁红衣多酚的体外抗氧化活性实验,结果表明松仁红衣多酚对羟自由基、DPPH自由基及过氧化氢均具有清除作用。      

松仁红衣中黄酮类化合物的提取工艺

本研究从松仁深加工的废弃物松仁红衣中提取黄酮类化合物。通过超声波预处理,采用单因素试验和L9(34)正交试验,考察乙醇浓度,提取时间,提取温度,固液比,提取次数对总黄酮提取率的影响。松仁红衣中总黄酮提取的最佳工艺为:乙醇浓度50%,提取时间2 h,提取温度70℃,固液比1:20(g/mL),提取次数2次,最大提取率为3.23%。     

Prebiotic potential of xylooligosaccharides derived from finger millet seed coat

The present study deals with the enzymatic production of xylooligosaccharides (XOS) from water-soluble xylan (WSX) extracted from finger millet CO9 seed coat and the evaluation of its prebiotic potential. The yield of XOS was 72%, when the WSX of the finger millet seed coat was treated with commercially available xylanase of Thermomyces lanuginosus. The XOS obtained when analyzed using high-performance liquid chromatography–evaporative light scattering detector (HPLC-ELSD) indicated a degree of polymerization (DP) of 2 and Electro Spray Ionization Mass Spectra (ESI-MS) revealed xylobiose as the major sugar. The presence of β-glycosidic linkages of XOS was identified by Fourier Transform Infrared Spectrometer (FTIR) and Nuclear Magnetic Resonance (NMR) studies. The XOS exhibited an antioxidant activity of 75% and prebiotic efficacy. Prebiotic activity in the presence of probiotic strains was strain specific and differences in the prebiotic activity score (PAS) between strains were evident. The cell-free supernatant of Lactobacillus plantarum grown on the XOS from finger millet seed coat showed strong antibacterial activities against four pathogenic microorganisms compared with commercial XOS. Finger millet seed coat represents an abundant and alternative source for the extraction of xylan and its use for prebiotic XOS production.     

罗望子种皮原花青素系统的非酶褐变动力学和食品配方因素影响

本研究旨在探讨不同食品配方因素下罗望子种皮原花青素提取物(tamarind seed coat proanthocyanidins extract,TSPA)系统的非酶褐变动力学与关键酚类组分,以解析食品配方因素与热贮藏对原花青素组分的影响,推断非酶褐变的可能机理.以55％(体积分数)乙醇溶液提取所得TSPA的总酚含量...     

澄清型绿豆衣饮料的配方研究

以护色后的绿豆浸提液、枣花蜂蜜和干菊花为主要原料,制备澄清型绿豆衣饮料。利用均匀设计进行澄清型绿豆衣饮料的配方研究,通过感官评定确定饮料的最佳配方为：绿豆浸提液92.58%、枣花蜜2.8%、白砂糖3.2%、菊花提取液1.4%、柠檬酸0.02%。该饮料呈自然的淡黄色,色泽清亮,口感清爽、香气适宜。     

电磁擦拭法在钢丝热镀锌中的应用

为提高热镀锌钢丝的生产效率及表面质量,控制锌耗成本,采用电磁擦拭法替代油木炭等传统擦拭法,并对生产技术进行改进:用异形陶瓷装置密封腔通高温氮气法进行气氛控制;多次水喷淋冷却方式降低钢丝温度;化学酸洗、电解酸洗相结合,并适当延长酸槽长度,确保钢丝足够的浸酸时间;铅浴脱脂或阴阳极交替电解碱洗,达到快速脱脂的目的;用大盘重放线架,放线装置设立矫直器。结果表明,电磁擦拭法生产线Dv值可达120 mm.m/min,较传统擦拭法生产效率提高3～5倍;锌层面质量控制精确度高,波动值降低50%～75%,钢丝表面光洁度好。     

Burberry女上装纸样研究

以风格较明显的Burberry女上装为研究对象,采用驳样的方法还原其成衣纸样。将该纸样与传统比例法绘制的女上装纸样进行对比,寻找Burberry成衣纸样的内在特点。