Influence of Potassium Fertilization on Enzymatic Activity, Phenolic Content and Discoloration of Potatoes

SUMMARY— Ontario potatoes, representing a variety that is very susceptible to precooking blackening, were grown in each of two consecutive years at different levels of potassium fertilization. In each of the two years of the study, the discoloration and total phenolic content of tubers decreased as potash applications were increased from 140 to 400 or 540 lb. per acre. The differences in discoloration were significant at the 1% level and the differences in phenolic content at the 5% level. Potatoes grown at high levels of potassium fertilization had higher cytochrome oxidase activity than those grown at lower levels. Potassium fertilization had no significant effect on polyphenol oxidase activity. A positive correlation (0.830) was found between the phenolic content and discoloration of potatoes as affected by potassium fertilizer.     

Zinc Fertilization Increases Ascorbic Acid and Mineral Contents of Potatoes

The effects of zinc fertilization on ascorbic acid and mineral concentration of Katahdin potatoes were investigated over 2 yr. During the first year zinc sulfate (ZnSO₄) was banded during planting at rates from 11.2 to 224 kg/ha in two locations in New York. During the second year ZnSO₄ was banded during planting at rates of 0, 22.4, 44.8 and 112 hg/ha at one of the locations. Ascorbic acid content of tubers was higher only with the 112 kg/ha ZnSO₄ treatment. Zinc fertilization resulted in higher Zn concentration in tubers during both years and at both locations. Zinc fertilization increased amounts of Ca, Mn, Cu, Al and Co but did not affect Cd content in potato tubers.     

Effects of Processing on Zinc Levels in Spinach, Beef, and Potatoes

Spinach, beef, and potatoes were subjected to combinations of cooking, freezing, retorting, and storage and analyzed for total zinc and water soluble zinc, before and after acid-enzyme digestion. Zinc and its complexes that were soluble were membrane filtered to exclude the passage of substances larger than 5,000 daltons. Approximately 30–50% of the total zinc in spinach systems and about 70–100% of the zinc in potato systems was water soluble. Practically none of the endogenous zinc in beef was water soluble. Regardless of processing method, essentially all zinc in spinach and potatoes and about half of the zinc in beef was released after acid-enzyme digestion. All of the spinach and potato zinc and at least a third of the beef zinc following digestion passed through the 5,000 dalton membrane.     

Effect of Molybdenum Fertilization on the Nitrogenous Constituents of Potatoes

The effect of molybdenum fertilizer on the nitrogenous constituents of Katahdin potatoes was investigated. The chemical constituents studied were total nitrogen, nonprotein nitrogen, and protein. Sodium molybdate was applied to the soil at rates of 0.0, 2.8, 6.7 and 10.1 kg/ha during the first year and 0.0, 5.6, 16.8 and 22.4 kg/ha during the second year of the study. The compound was applied to the soil one day prior to planting of the seed potatoes. During both years of the study, tubers from plants receiving molybdenum fertilization were significantly higher (p < 0.01) than the controls in total nitrogen and protein and significantly lower (p < 0.01) in nonprotein nitrogen at all levels of molybdenum application. Greatest increases in total nitrogen and protein were observed in tubers from plants receiving 22.4 kg/ha of sodium molybdate.     

Valorization of Pinus taeda bark: source of phenolic compounds,tannins and fuel

Pine bark is a byproduct of wood processing which is usually burnt for energy. This article analyzes the liquid–solid extraction of Pinus taeda bark to obtain phenolic compounds by using response surface methodology to determine extraction conditions. The independent variables studied were temperature, ethanol concentration and solid–liquid ratio, and the variables to be optimized were total extractives yield, phenolic content, antioxidant capacity and condensed tannins yield. In addition, the extract was characterized by Fourier transform infrared spectroscopy and UV–Vis spectroscopy. Furthermore, extraction kinetics were modeled, and mass transfer mechanisms were studied. The extraction condition that maximizes extraction yields was defined at 50 °C, with a solid–liquid ratio of 1/10 and with an ethanol concentration of 50%. The condensed tannins yield was 4.01 g catechin equivalent (CE)/100 g pine bark dry base (d.b.), the total extractive yield was 9.83 g extract/100 g pine bark d.b. and the Stiasny number was 77. The extract showed a FRAP antioxidant concentration of 20.89 mmol ascorbic acid equivalent (AAE)/100 g pine bark d.b and 0.35 mmol trolox (TRE)/g pine bark d.b. for ABTS assay. The results showed that extended Fick’s law was adequate to describe the extraction kinetics. The extraction did not significantly affect the calorific value of bark (21 kJ/g d.b.). After extraction, the ashes were reduced by 13% and potassium (K) by 48%. The extraction of Pinus taeda to obtain phenolic content is technically feasible, and this paper provides the scientific ground for further scaling the process.

     

Effects of drying and extrusion on colour,chemical composition,antioxidant activities and mitogenic response of spleen lymphocytes of sweet potatoes

Antioxidative and physiological property changes of freeze-dried, hot air-dried and extruded products made from two different colours of sweet potatoes (yellow and orange) were investigated. The results showed that there were no significant differences of dietary fibre content amongst all the treatments, except that the extruded products of orange sweet potatoes had higher dietary fibre contents. However, the water solubility index (WSI) values and antioxidant content were significantly different between yellow and orange sweet potatoes, and significantly different amongst freeze-dried, hot air-dried and extruded samples. The WSI values of the extruded samples were significantly higher than those of the hot air- and freeze-dried samples. The freeze-dried samples of orange sweet potatoes had more total phenolic compounds, β-carotene, and anthocyanin and had better scavenging effect on DPPH radicals than had freeze-dried yellow sweet potatoes. However, the scavenging effect on DPPH radicals was appreciably greater for hot air-dried than freeze-dried yellow sweet potatoes, but this trend was opposite for orange sweet potatoes. The extrusion process significantly increased the WSI values, scavenging effect on DPPH radicals and total phenolic compounds but decreased the β-carotene and anthocyanin for both yellow and orange sweet potatoes. At lower concentration (25–50 μg/ml), the methanolic extract of freeze-dried yellow sweet potatoes possessed a greater capacity of increasing the mitogenic response than did freeze-dried orange sweet potatoes; at higher concentration (100–200 μg/ml), the proliferation of the lymphocytes increased when stimulated with mitogen Con A for all the samples. This suggests that mitogen Con A selectively promotes T-cell-dependent proliferative activity.     

Effect of the ratio of zinc amino acid complex to zinc sulfate on the performance of Holstein cows

Multiparous (n = 70) and primiparous (n = 66) Holstein cows were balanced by 305-d previous mature-equivalent milk yield and parity and assigned to 1 of 3 dietary treatments to evaluate the ratio of zinc sulfate to zinc amino acid complex (CZ) in pre- and postpartum Holstein cows fed diets containing 75 mg of added zinc/kg. Treatments were (1) 75 mg of supplemental zinc/kg of dry matter (DM) provided entirely as zinc sulfate (0-CZ); (2) 0-CZ diet, except 33.3 mg of zinc sulfate/kg of DM in the prepartum and 15.5 mg of zinc sulfate/kg of DM in the postpartum diet were replaced by CZ from Availa-Zn (16-CZ; Zinpro Corp., Eden Prairie MN); and (3) 0-CZ diet, except 66.6 mg of zinc sulfate/kg of DM in the prepartum and 40.0 mg of zinc sulfate/kg of DM in the postpartum diet was replaced by Availa-Zn (40-CZ). Cows were housed at the Iowa State University Dairy Farm and were individually offered a total mixed ration containing dietary treatments beginning at 28 ± 15 d before expected calving date until 250 d in milk. Relative to 0-CZ, multiparous cows (but not primiparous) fed CZ (16-CZ or 40-CZ) had increased (20%) colostrum IgG concentrations. Prepartum DM intake (DMI) was decreased with CZ supplementation. Postpartum DMI was decreased in cows fed CZ, whereas milk yield (MY) was increased in the 40-CZ-fed cows relative to those fed both 0-CZ and 16-CZ. Feed efficiency increased linearly when measured as MY/DMI, 3.5% fat-corrected MY/DMI, and solids-corrected MY/DMI. Regardless of level, feeding CZ decreased services per conception. Feeding 16-CZ decreased milk fat concentration and feeding CZ linearly increased milk urea nitrogen concentration. In summary, supplementing zinc as a mixture of CZ and zinc sulfate, as opposed to supplementing only zinc sulfate, has beneficial effects on production parameters in dairy cows, with those benefits becoming more apparent as the ratio of CZ to zinc sulfate increases.     

马铃薯抗氧化活性成分研究

分析了宁夏地区种植的8种马铃薯总酚、总黄酮含量,并采用高效液相色谱法测定马铃薯中酚酸种类及其含量;通过体外抗氧化评价模型比较8种马铃薯对超氧阴离子、羟基自由基、DPPH自由基、ABTS自由基清除能力及FRAP铁还原能力。结果表明:黑美人总酚含量最高,为400.38 mg/100 g,夏波蒂总酚含量最低,为233.93mg/100g;费乌瑞它黄酮含量最高,为107.39mg/100g,庄薯3号黄酮含量最低,为33.17mg/100g;所有品种马铃薯的主要酚酸物质均为绿原酸,其中黑美人含量最高(91.46%);绿原酸含量与酚酸、黄酮含量呈极显著正相关性(P0.01);酚酸含量与ABTS自由基清除能力相关性最大;黄酮含量与羟基自由基清除能力呈极显著负相关(P0.01);绿原酸含量与ABTS自由基清除能力相关性最大。     

新型食品添加剂丙酸锌的制备及应用性能研究

研究了以丙酸钙和硫酸锌为原料 ,经复分解反应制备新型食品添加剂———丙酸锌的主要合成工艺条件 ,确定了丙酸钙用量和各反应物的最适浓度 ,即x(丙酸钙 ) :x(硫酸锌 ) =1 16∶1,C(丙酸钙 ) =1 0 75mol/L ,C(硫酸锌 ) =1 2 39mol/L ,在上述条件和 80℃时反应 40min ,丙酸锌收率可达 93 6 %以上。同时还对丙酸锌的生物利用度、药动学和营养强化效果等作了探讨 ,为其在食品领域的推广使用提供了依据     

施肥方式对玉米-大豆套作体系氮素吸收利用效率的影响

通过田间试验探讨了Al（N,210kg·hm^-2）、A2（N,270kg·hm^-2）、A3（N,330kg·hm^-2）3种施氮水平和距窄行玉米B1（0cm）、B2（15cm）、B3（30cm）、B4（45cm）4种施肥距离对玉米一大豆套作体系氮素吸收利用效率的影响。结果表明,与习惯施氮（A3）相比,减量施氮（A1、A2）提高了大豆R2、R5期单株根瘤数、根瘤干重和根瘤固氮潜力,以距玉米15cm处施肥的根瘤固氮能力较强;玉米、大豆的籽粒产量、地下部植株氮素吸收量和氮肥利用率随施氮量的增加呈先增加再降低的趋势,以A2处理的最高;施肥距离过大和过小均不利玉米、大豆产量的提高和氮素的吸收利用,以距玉米15～30cm处施肥效果最佳;减量施氮18％（A2）时,B2、B3处理相对常规穴施（B1）处理,玉米、大百及玉米一大豆系统的籽粒产量、植株氮素吸收量、氮肥利用率和土壤总氮含量均显著提高,土壤氮素贡献率显著降低。     

The potassium requirement of crops grown in rotation

A 5-year trial measured the effect of varying rates of potassium fertiliser applied in combination with two rates of nitrogen to a rotation: potatoes, kale, barley, grass cut for conservation and wheat. Residual values of potassium applied during the rotation were measured on a crop of spring wheat planted in the sixth year. Crops grown in the rotation responded increasingly to potassium as follows: kale, barley, grass, wheat, potatoes. The higher rate of potassium applied (706 lb/acre^a K in 5 years) was justified by the total value of crops harvested; this return was derived mainly from potatoes and wheat. The higher rate of potassium applied was insufficient to maintain the soil in K balance (applications less removal in crops) when the higher rate of nitrogen was used. Soil analysis indicated no residues from the lower rate of K applied but the higher rate raised available K levels appreciably. The wheat crop grown after 5 years under the rotation showed residues from the lower rate of K applied equivalent to 55 lb/acre fresh K but no additional residue from the higher rate.     

Extraction,distribution and characterisation of phenolic compounds and oil in grapeseeds

Five factors, extraction means, extraction repeats, extraction solvents, sample granularities, and grinding manners, were investigated and compared to optimise the extraction methods of phenolic compounds from grapeseed. Twenty minutes sequential sonication for three repeats was a preferred extraction means for assessment of phenolic content in grapeseed over three repeats 100-min sequential mechanical agitation. Methanol/water/HCl (70:29:1, v/v/v) was the best among the solvent compositions tested. Grinding granularity showed a significant (p = 0.05) effect on the yield of phenolic compounds when the sample was ground with a grinder and separated to different granularities by sieves. Grinding sample with mortar in liquid nitrogen could provide samples with uniform size and thus give a more consistent evaluation of phenolic compounds in grapeseed. Significant correlation coefficients (p < 0.01) among total phenols, total flavan-3-ols, and total proanthocyanidins contents in grapeseed extracts were observed. In addition, phenolic compounds and oil were very unevenly distributed in grapeseed as about 90% of phenolic compounds were observed in seed coat while about 60% of oil was in the endosperm and embryo.     

滴灌大豆氮素积累与分配的肥效差异

利用节水滴灌技术,通过设置不同的肥料用量和施肥时期处理,研究其对滴灌大豆氮素积累、分配、利用及产量的影响,以形成节水灌溉与施肥相结合的栽培技术。其中种肥为尿素75kg/hm^2、磷酸二铵150kg/hm^2、硫酸钾90kg/hm^2;滴肥为尿素127.5kg/hm^2、磷酸二氢钾为133.5kg/hm^2。结果表明,在滴灌条件下前期种肥的供给对大豆氮素积累及产量的形成非常重要,T1（1/2种肥）、T2（种肥）、T4（1/2种肥＋花期1/2滴肥）、T5（1/2种肥＋结荚期1/2滴肥）处理的滴灌大豆氮素积累量大,转移率和吸收利用率较高。综合产量因素,在施用种肥,结荚期再施用滴肥（即T5处理下）,施肥方式效果最佳。     

无机氮源对出芽短梗霉发酵普鲁兰多糖分子量的影响

以出芽短梗霉(Aureobasidium pullulans)CGMCC No.11062为出发菌株,研究五种无机氮源对普鲁兰多糖产量、结构、纯度及分子量的影响。结果表明:无机氮源种类对普鲁兰多糖产量和分子量产生显著影响,未影响普鲁兰多糖结构和纯度。其中,以硫酸铵(1.5 g/L)为唯一氮源时普鲁兰多糖产量达到32.84 g/L,重均分子量(Weight-average Molecular Weight,Mw)最大,为799823ku。硫酸铵浓度对普鲁兰多糖的产量和分子量影响显著,而未显著影响普鲁兰多糖结构。随着硫酸铵浓度的增加,普鲁兰多糖产量和分子量同时增加;当硫酸铵浓度为1.5 g/L时,普鲁兰多糖的产量出现最大值,为32.45 g/L;而当硫酸铵浓度为2.1 g/L,普鲁兰多糖重均分子量(Mw)最大,达到1236958 ku。所有制得的普鲁兰多糖纯度在95%~99%之间。这些研究可为不同分子量普鲁兰多糖生产提供技术指导。     

Analysis of crops and soils for residues of the soil insecticides aldrin and "Telodrin"

Aldrin (2 lb/acre) and ‘Telodrin’ (0.5 lb/acre) were applied as emulsifiable concentrates to plots once in 1961 or in three annual applications 1961-3. Residues taken up into cabbage, carrots, celery, onions, potatoes and sugar-beet, and those remaining in the soil have been determined by electron-capture gas–liquid chromatography. The insecticide residue level in all crops was less than 0·1 ppm. Residues were found in crops grown in loam soils but not in peat, and only in the root crops (carrots, potatoes and sugar-beet). Crop residues did not increase markedly with annual re-treatment, but levels greater than 0·01 ppm continued to occur in carrots grown in loam soils in later seasons when treatment was not repeated. Residues were lost rapidly from soil immediately following application, dropping to about 15% of the initial values after a year, but loss thereafter was at a much slower rate.     

The effect of popping,soaking, boiling and roasting processes on antinutritional factors in chickpeas and red kidney beans

This study was conducted to determine the effect that a popping head (like a rice cake machine), a low-shear and low-water processing technology, has on the concentration of antinutritional factors in chickpeas and red kidney beans. Seeds were popped under several parameters (popping time, sample format and equipment type) and analysed against soaking (1:5 w/v in reverse osmosis water for 24 h), roasting (100 g at 180 °C for 20 min) and boiling (1:5 w/v in reverse osmosis water at 100 ± 1 °C for 1 h) processes. Popping and roasting significantly reduced phytic acid content in chickpeas (6%–22%) and red kidney beans (16%–39%). In contrast, phytic acid content after soaking and boiling was not significantly different to raw seeds. Condensed tannins were significantly reduced in red kidney beans after soaking (74%), boiling (100%) and 4 s popping (28%–42%) treatments and increased in both pulses after roasting (137%) and 8 s popping (21%–47%). Further analysis showed that the soluble phenolic content increased with popping, but total and bound phenolic content was reduced. These results demonstrate that the high temperatures and pressures applied during the popping process effectively reduce antinutritional factors in pulses, compared to conventional processing methods.     

木本泥炭新型肥料在砖红壤甘蔗上的应用

在粤西砖红壤上以粤糖03-393为供试品种,通过设置空白对照、常规推荐用肥、常规推荐用肥与分别添加5种木本泥炭肥料配施共7个处理的田间试验,研究了木本泥炭新型肥料对新植甘蔗农艺性状、蔗茎产量、理论产糖量及土壤肥力的影响。结果表明:与仅施常规推荐用肥相比,施用木本泥炭生物有机肥处理能显著增加甘蔗有效茎数。5个增施木本泥炭肥料处理的蔗茎产量和理论产糖量均比仅施推荐用肥处理显著增加,土壤中全氮、全磷、速效磷、全钾和有机质的含量也显著提高,经济效益相应得到增加。     

利用廉价原料生产聚谷氨酸的研究

目的 降低聚谷氨酸的生产成本.方法 从聚谷氨酸发酵所需的氮源和碳源出发,分别研究了小麦水解蛋白、豆饼粉、豆粕粉、玉米蛋白、玉米浆等有机氮源和甘蔗糖蜜、甜菜糖蜜、葡萄糖蜜、玉米糖蜜等碳源对聚谷氨酸发酵产量的影响,在此基础上通过单因素实验优化了玉米浆、硫酸铵、甜菜蜜、谷氨酸钠的添加量,最后通过发酵罐发酵比较了优化后的工艺与...     

Prediction of the fertiliser needs of sugar-beet grown on fen peat soils

The fertiliser requirements of sugar-beet grown on fen soils were tested in 52 experiments from 1963 to 1969. In some fields, N.P.K and Na and, especially N and P, greatly increased yields, but the average responses obtained with the four elements were small. To help to predict where and how much fertiliser was needed for sugar-beet, soils were grouped according to soil analysis and classified by loss on ignition. Sugar-beet grown on soils with less than 20 μg/ml P (extracted with sodium bicarbonate) needed 1·20 cwt/acre P₂O₅, with 21–45 μg/ml P, 0·75 cwt/acre P₂O₅, and with more than 45 μg/ml P no fertiliser was required. Most soils contained high concentrations of K; with less than 100 μg/ml K (extracted with ammonium nitrate), 2·00 cwt/acre P₂O was probably justified; with 100–250 μg/ml, 1·00 cwt/acre K₂O was needed. Most of the responses to agricultural salt were by crops on soils with exchangeable sodium concentrations of less than 30 μg/ml Na. Loss on ignition was related to response to N fertiliser; when the loss was 14–25%, N increased yield by 6 cwt/acre sugar and 1·2 cwt/acre N fertiliser was Heeded and when the loss was 26–35%, the yield was increased by 3·5 cwt/acre and 0·6 cwt/acre N was needed. With greater losses there was little response.     

Salinity impact on fruit yield,essential oil composition and antioxidant activities of Coriandrum sativum fruit extracts

This study is designed to examine the fruit essential oil composition, the total phenolic amounts and the antioxidant activities in methanolic extracts of Coriandrum sativum under saline conditions. Increasing NaCl levels to 75 mM reduced significantly the fruit yield by 36%. The essential oil yield was 0.30%, based on the dry weight; it increased by 77% and 84% at 50 and 75 mM NaCl, respectively, in comparison to the control. The major constituents were linalool and camphor, whose amounts increased with increasing NaCl concentrations. Antioxidant activities of the methanol extracts were determined by three different test systems, namely DPPH, β-carotene/linoleic acid and reducing power assays. In these three test systems, the highest activity was exhibited in control plants and was reduced significantly with increasing NaCl levels. In control plants, the total phenolic amount was 1.04 mg GAE/g DW which decreased by 43% and 66% at 50 and 75 mM NaCl, respectively.