Smart “Sticky Note” for strain and temperature sensing using few-layer graphene from exfoliation in red spinach solution

The synthesis of few-layer graphene from graphite typically uses N, N methyl pyrrolidone (NMP) or dimethylformamide (DMF) due to the strong affinity of both solvents for graphite. However, NMP and DMF are known as carcinogens and a long-time exposure to these substances may subject users to potential risk of major health issue later. Therefore, a replacement with dispersing solvent that is not only harmless but also able to exfoliate graphite at an excellent concentration yield must be outlined for a sustainable mass-production of graphene. In this work, we have successfully exfoliated graphite to few-layer graphene with a recorded yield concentration of up to 0.75°mg/ml (2.5°h) just by using extracted red spinach/water mixture as an exfoliating medium. The prepared graphene was found to possess less structural defect (I_D/I_G: 0.5) and high C/O ratio (6.8) and can be used further as an electrical conductive ink for smart “Sticky Note” sensor. The fabricated device was able to detect strain and temperature with gauge factor and temperature coefficient resistance of 23.5 and −32.14 $\times$ 10^-4°Ω/°;C, respectively. We believe that this study would be useful for the preparation of environmental-friendly graphene that is not only strain and thermally sensitive but also producible at low -cost.     

Nitrogen removal from eutrophic water by floating-bed-grown water spinach (Ipomoea aquatica Forsk.) with ion implantation

The aim of this study was to investigate the use of water spinach (Ipomoea aquatica Forsk.) with N(+) ion-beam implantation for removal of nutrient species from eutrophic water. The mutated water spinach was grown on floating beds, and growth chambers were used to examine the growth of three cultivars of water spinach with ion implantation for 14 days in simulated eutrophic water at both high and low nitrogen levels. The specific weight growth rates of three cultivars of water spinach with ion implantation were significantly higher than the control, and their NO(3)-N and NH(4)-N removal efficiencies were also greater than those of the control. Furthermore, compared with the control, the nitrogen contents in the plant biomass with ion implantation were higher as well.     

Shelf Life and Sensory Characteristics of Baby Spinach Subjected to Electron Beam Irradiation

Abstract: The use of ionizing radiation for the control of foodborne pathogens and extending the shelf life of fresh iceberg lettuce and fresh spinach has recently been approved by the U.S. Food and Drug Administration. The efficacy of electron beam irradiation for controlling foodborne pathogens has been reported. For this experiment, the effectiveness of electron beam irradiation on the microbiological and sensory characteristics of fresh spinach was studied. Total aerobic plate counts were reduced by 2.6 and 3.2 log CFU/g at 0.7 and 1.4 kGy, respectively. Lactic acid bacteria were reduced at both doses of e-beam but grew slowly over the 35 d of the experiment. Yeasts and molds were not reduced in samples exposed to 0.7 kGy whereas 1.4 kGy significantly reduced microbial counts. Gas compositions (O₂ and CO₂) were significantly different than controls. Oxygen levels inside the spinach sample bags decreased over time; however, O₂ levels did not drop below 1% that can induce anaerobic fermentation. CO₂ levels for all treatments increased through day 4; yet 7 d after irradiation, CO₂ level differences were not significant in both control and irradiated samples. Irradiation dose did not affect the basic tastes, aromatics, or mouth feels of fresh spinach, however; hardness attributes decreased as irradiated dose increased and slimy attributes of fresh spinach were higher in control samples compared to irradiated samples.     

菠菜汁低温火腿肠加工工艺研究

以猪肉为主料，菠菜汁为配料，以玉米淀粉、大豆分离蛋白等为辅料，通过单因素试验和正交试验，针对菠菜汁低温火腿肠的配方进行了研究，结果表明：菠菜汁添加量为3％、肥瘦肉比例为7：3，淀粉添加量为10％、香辛料添加量1．5％，产品质量最好。     

不同镉水平对菠菜生长及营养元素含量的影响

不同镉水平对两种菠菜澳洲大叶、新世纪全能的生长及营养元素含量影响研究结果表明:培养液中添加镉后能够抑制两种菠菜的生长,可以显著降低菠菜地上部的干重。两种菠菜地上部分及根中的镉含量随培养液中镉浓度增加而显著增加。镉主要累积在菠菜的根中。镉影响菠菜对营养元素的吸收及分配,澳洲大叶地上部的Ca、Mg、Fe和Mn的含量显著增加,新世纪全能地上部Fe含量显著增加。这种影响随着不同元素、不同植株部位及镉离子在介质中浓度的不同而有所差异,基因型间存在一定的差异。     

木瓜蛋白酶对菠菜叶蛋白的改性研究

利用木瓜蛋白酶对菠菜叶蛋白进行酶法改性,通过均匀试验得出,酶解菠菜叶蛋白的最佳条件为温度55℃,pH6.5,E/S为0.5%,时间为2 h,菠菜叶蛋白的水解度可达15.85%;通过比较在不同pH下酶解前后菠菜叶蛋白的部分功能性质,结果表明,酶解后菠菜叶蛋白的等电点由原来的4.0漂移至3.4,且其溶解性、起泡性、稳定性及其乳化性较改性前均有不同程度的提高。     

Effect of processing on the amino acid content of New Zealand spinach (Tetragonia tetragonioides Pall. Kuntze)

The aim of this work was to evaluate the effect of processing on the amino acid content and protein quality of New Zealand spinach (Tetragonia tetragonioides Pall. Kuntze). In this research, fresh and cooked New Zealand spinach as well as two frozen products prepared for consumption, one obtained using the traditional method (blanching–freezing–storage–cooking) and the other a convenience food product obtained using a modified process (cooking–freezing–storage–defrosting and heating in a microwave oven), were analysed. Glutamic acid was the dominant amino acid in fresh New Zealand spinach, and the limiting amino acids were cystine and methionine. Technological and culinary processing caused a significant increase in amino acid content in 100 g of edible portion, with the exception of methionine and cystine in frozen products prepared for eating. Changes in amino acid content expressed in g/16 g of N (which corresponded to 100 g tissue protein) were not significant, with the exception of the lower glutamic acid content in the frozen product obtained using traditional processing method.     

The use of bacterial alkaline phosphatase assay for rapid monitoring of bacterial counts on spinach

ABSTRACT:  This study was undertaken to evaluate the applicability of bacterial alkaline phosphatase (ALP) activity for rapid monitoring of total mesophilic bacteria counts in spinach. A set of fresh and decayed spinach mixtures were tested to rapidly (10 min) monitor spinach bacterial counts. To assay ALP activity, Lumigen APS-5 was used as a substrate. Bovine ALP was reduced after heat treatment at 75 °C for 1 min; in contrast, bacterial ALP activity increased. To differentiate bacterial ALP from other ALP, heat treatment (75 °C, 1 min) was applied before measurement. As a result, a regression equation was established between the actual mesophilic aerobic bacteria count and ALP activity of spinach mixtures ( r = 0.90). The predicted total mesophilic aerobic bacterial count calculated from the fitted regression line (predicted log₁₀ CFU/g = 0.00056 × ALP values + 1.4002) showed a high correlation with the actual observed total bacterial count ( r = 0.93). The ALP assay is a simple and rapid method to utilize for estimation of existing or contaminating microorganism levels on spinach.     

Pressurized liquid extraction of flavonoids from spinach

ABSTRACT:  Pressurized liquid extraction (PLE) using water and a 70:30 mixture of ethanol and water over the temperature range of 50 to 190 °C was used to extract flavonoids from dried spinach. The total phenolic content, antioxidant capacity, color, and browning indices of the extracts were also evaluated. PLE using a 70:30 mixture of ethanol and water was more effective than water in extracting flavonoids from spinach. Flavonoids were effectively extracted over the temperature band of 50 to 130 °C with water and 50 to 150 °C with ethanolic solvent. Levels of total phenolics and ORAC values increased with increasing extraction temperature, indicating that flavonoids were minor contributors to antioxidant capacity at elevated extraction temperatures. Browning of ethanolic extracts correlated highly with ORAC values over the temperature range of 50 to 190 °C, and the ORAC values of the large molecular weight fraction (> 1000 Da) increased linearly over the temperature range, indicating that Maillard polymers were the major contributors to antioxidant capacity. The results illustrate that PLE temperatures of < 130 °C for water or < 150 °C for ethanolic solvent may be used to extract flavonoids, followed by a high temperature (> 170 °C) extraction to generate antioxidant-rich moieties.     

Storage of Spinach Under Low Oxygen Atmosphere Above the Extinction Point

The extinction point of spinach was <0.4% but above 0.2% O₂ at 0° and 5°C. Respiration rates were ～2.3 times greater at 5°C than at 0°C and were similar among cultivars. In 0.8% O₂ atmosphere, O₂ uptake of three cultivars was reduced by an average of 53% and CO₂ production was reduced by 35% relative to those stored in air. Deterioration of leaves was reduced by 30 to 54%, while weight loss, color and chlorophyll content were not affected by the 0.8% O₂ atmosphere. Thus O₂ could be allowed to be depleted to 0.8% in modified atmosphere packaging without quality loss due to anoxia.