The influence of thermal process of coloured potatoes on the content of glycoalkaloids in the potato products

Potato products made from potato varieties with coloured flesh (red and blue-fleshed potatoes) may be an interesting alternative to traditional products. The purpose of this study was to determine the influence of peeling, cooking and frying of red and blue-fleshed potato tubers on the content of glycoalkaloids (α-solanine and α-chaconine) in processed potato products. The material taken for the study consisted of seven coloured potato varieties. French fries and crisps were prepared from two potato variety: Rosalinde and Blue Congo. The content of total glycoalkaloids (TGA) in raw material before and after peeling, in cooked unpeeled and peeled potatoes and also in fried potato products have been determined by HPLC method.     

The influence of dehydrated potatoes processing on the glycoalkaloids content in coloured-fleshed potato

The aim of this study was to determine the effect of different temperatures of blanching and pre-drying used in the laboratory production of dried potato dice on the content of glycoalkaloids in red and blue fleshed potato varieties.     

Impact of oregano and virgin olive oil phenolic compounds on acrylamide content in a model system and fresh potatoes

In this study the effect of olive oil and oregano phenolic compounds on antioxidant activity (AOA) and acrylamide formation in a model system and fresh potatoes was evaluated. The addition of oregano phenolic extract in the model system resulted in an increase of AOA and in a reduction of acrylamide content, up to 49%, after heating. On the contrary, addition of olive oil extract resulted in AOA reduction and a concentration-dependent effect on acrylamide formation was observed with a reduction up to 15% (p < 0.05) followed by an increase up to 48%. The same trend, in acrylamide formation, was observed in fresh potatoes but to a lower extent. Finally, addition of tyrosol, oleuropein and p-hydroxyphenylacetic acid in the model system resulted in acrylamide reduction up to 50%. The discrepancy in acrylamide formation, caused by phenolic compounds, is ascribed to their structure and related to their terminal functional hydroxyl and aldehydic groups.     

Direct analysis for the distribution of toxic glycoalkaloids in potato tuber tissue using matrix-assisted laser desorption/ionization mass spectrometric imaging

A simple and rapid analytical method for detection and spatial distribution of glycoalkaloids in potato tubers has been developed for the first time using matrix-assisted laser desorption/ionization mass spectrometric imaging (MALDI-MSI). For effective MALDI-MSI analysis, we have developed a uniform matrix coating method using 2,5-dihydroxybenzoic acid (2,5-DHB) as the preferred matrix which results in better sensitivity than 2,4,6-trihydroxyacetophenone (2,4,6-THAP) using MALDI-TOF. The relative concentrations of two major and two minor glycoalkaloids, α-chaconine and α-solanine, dehydrochaconine and dehydrosolanine, were clearly detected and distinguished in various parts of potato tuber and their relative amounts were directly compared. We also successfully showed the relative concentrations of glycoalkaloids that were accumulated by light exposure during storage using MALDI-MSI. Therefore, MALDI-MSI has been shown to be a useful technique for screening toxic and bioactive metabolites in foods and medicinal plants.     

Geometrical model to calculate the consumption of sewing thread for 301 lockstitch

Sewing thread is one of the most basic yet important components of a garment. Thread consumption for the lockstitch (Class 301) can be calculated by using its geometrical shape. This paper aims to develop a geometrical model to calculate the thread consumption for lockstitch (Class 301). Based on the basic geometry of lockstitch, a model has been proposed. The model is derived mathematically taking into account different variables: stitch length, stitch density, material thickness, and interlacing. Finally, the model was verified for 19 samples by comparing actual thread consumption with predicted thread consumption. The proposed model predicts the thread consumption with 97% accuracy. Sensitivity analysis is also performed to determine the significant influencing factor affecting the thread consumption. The proposed model can predict the thread consumption precisely for 301 lockstitch. Therefore, this model is useful for the apparel industry.     

用高效液相色谱(HPLC)法测定饮料中维生素C的含量

建立了一种饮料中Vc的反相高效液相色谱 (HPLC)测定法。高效液相色谱系统采用Shim packVP ODSC 18柱 ,甲醇 /磷酸二氢钾缓冲液 =75 /2 5 (V/V)作流动相 ,流速为 1 0ml/min ,检测波长为 2 6 6nm。Vc在浓度 0 0 5 0～ 0 30 0mg/ml内有良好的线性关系 ,线性回归方程为y =4845 5 716 96 3x 772 6 0 10 (R =0 9999)。分析方法中回收率平均为 99 2 3%,标准偏差s =0 0 0 18,变异系数CV =1 90 %。Vc的最低检测限为 2 5 0× 10 7mg。     

反相高效液相色谱法(RP-HPLC)测定麦汁中的草酸

利用反相高效液相色谱法(RP-HPLC)测定麦汁中的草酸含量。对各种色谱条件进行了研究,最终确定色谱柱Hypersil ODS 4.0×125mm,流动相为0.5%KH2PO4-0.5mmol/L TBA(tetrabutylammonium salt,四丁基铵盐)水溶液,pH2.0,紫外检测波长220nm。试验证明该方法能有效地分离麦汁中的草酸和酒石酸,准确灵敏、回收率高、重复性好,并且操作简便,可应用于啤酒生产中草酸含量的检测。     

Agaritine content of 53 Agaricus species collected from nature

Fifty-three different species of the genus Agaricus were collected in the Czech Republic during the period 1998–2001 and identified by an experienced mycologist. The samples were analysed for agaritine (N ²-(γ-L-glutamyl)-4-hydroxymethylphenylhydrazine) content, a precursor to a suspected rodent carcinogen. There was a huge variation in agaritine content between species, but less variation between samples of a species. Whereas the cultivated mushroom Agaricus bisporus commonly contain 200–500 mg agaritine kg^?1 fresh weight, no less than 24 of the 53 species contained agaritine levels above 1000 mg kg^?1 fresh weight. The highest level was found in A. elvensis containing up to 10, 000 mg kg^?1 fresh weight. Twenty species contained intermediate levels (100–1000 mg kg^?1), and nine species were below 100 mg kg^?1. Some of the species producing low levels of agaritine might be candidates for future strain development of Agaricus mushrooms for cultivation. No correlation could be observed between agaritine content and size of the mushroom, week of the year when collected, year of collection, or site of collection. Besides occurring in the genus Agaricus, some species of the genera Leucoagaricus and Macrolepiota were also shown to contain agaritine.     

充氮储藏的菜籽油食用期品质变化

以不添加抗氧化剂的一级菜籽油为原料,酸价、过氧化值、p-茴香胺值为监测指标,在模拟家庭食用期储藏条件下,探讨了充氮储藏的菜籽油(2. 5 L/桶)在3个月食用期内的品质变化规律。结果表明:充氮储藏的菜籽油在3个月的食用期内酸价(KOH)未超过一级菜籽油的限量值0. 2 mg/g;充氮储藏的菜籽油比空白对照组的过氧化值达到5. 0 mmol/kg的时间延长了20 d;充氮储藏的菜籽油p-茴香胺值的变化较为平缓,在前30 d内变化不大。充氮储藏提高了菜籽油的氧化稳定性,该储藏方法可以成为菜籽油的一种新型绿色的储藏技术。     

Changes in unreacted starch content in corn during storage

In the dry grind process, corn is ground, mixed with process water and cooked; starch is enzymatically hydrolyzed to sugars, and subsequently fermented to ethanol by yeast. The conversion of starch into ethanol, however, is not complete as distillers dried grains with solubles (DDGS) often contain more than 5% starch. The amount of unreacted starch represents inefficiencies in the process and reducing this amount is important to improving profitability of the ethanol industry. Additionally, dry grind facilities have reported seasonal variation in ethanol yields. In order to minimize variation in ethanol yields and the amount of unreacted starch in DDGS, it is important to understand the effects that storage temperature and time have on the digestibility of the corn starch. While starch quality is largely controlled by genetics and growing conditions, postharvest practices (handling, storage, and processing conditions) also affect starch composition and structure. In this study, changes in unreacted starch content of corn during storage were monitored to provide an explanation for the seasonal variation in ethanol yields observed by dry grind facilities. Yellow dent corn was harvested in 2011 and 2012 and stored indoors, outdoors, and under refrigeration for 5–12 mo. Results with the 2011 harvest corn showed unreacted starch content ranging from 2.17 to 14.1% over a 48 wk period. Unreacted starch was more influenced by storage time, initially decreasing at a rate of 0.31% per wk during the first 10 wk and steadily increased at an average rate of 0.16% per wk for the duration of storage. Results with the 2012 harvest corn, however, showed a higher average unreacted starch content of 13.0% during 20 wk of storage and no appreciable change in unreacted starch content regardless of storage temperature.     

Understanding consumer resistance to the consumption of organic food. A study of ethical consumption,purchasing, and choice behaviour

Although the demand for organic food is growing globally, the mainstream consumption of organic food is far less. The present study attempts to understand the underlying reasons for consumer resistance toward consuming organic food using the theoretical framework of innovation resistance theory (IRT). The study further examines the association between different consumer barriers and purchase decisions (purchase intentions, ethical consumption intentions, and choice behaviour) at different levels of buying involvement and environmental concerns. The collected data, consisting of 452 consumers, were analyzed by structural equation modeling approach. The results showed that value barrier shared a negative association with purchase intentions and ethical consumption intentions. Ethical consumption and purchase intention were found to have a direct influence on choice behaviour. Additionally, the relationship between ethical consumption intention and choice behaviour is mediated by purchase intention. However, no significant differences have emerged based on the level of buying involvement and environment concerns. The findings of the study provide insight into public policymakers, marketers, suppliers, and consumer associations by enhancing their current understanding of buying behaviour of the growing organic food community.     

Effects of the methods of pre-treatment before freezing on the retention of chlorophylls in frozen leaf vegetables prepared for consumption

The investigation included kale, New Zealand spinach and spinach. The evaluation covered the raw material; the raw material after blanching; the raw material after cooking; and frozen products prepared for consumption after 0, 4, 8 and 12 months of refrigerated storage. Both the traditional method of freezing (blanching before freezing) and the modified method of freezing (cooked before freezing) were used in the experiment, as well as two storage temperatures, T = −20 °C and T = −30 °C. The content of chlorophylls in fresh kale was four times that in New Zealand spinach and 1.5 times that in spinach. With the exception of New Zealand spinach, blanching and cooking significantly reduced the content of chlorophylls. In kale products prepared for consumption, the content of chlorophylls decreased in each successive stage of the investigation. In products of New Zealand spinach and spinach, the losses were usually not significant. After 12 months of refrigerated storage, frozen kale products prepared for consumption retained 52–65% of total chlorophylls compared with the content in the raw material; products of New Zealand spinach and spinach retained 66–71%. In kale and New Zealand spinach, the content of chlorophyll a decreased more rapidly than that of chlorophyll b, while in spinach the converse was true. The kale products obtained using the modified method contained more chlorophylls, while in the two spinach species their content was lower. The lower storage temperature resulted in a higher retention of chlorophylls in vegetables.     

不同来源大豆中生育酚含量的HPLC测定与比较

采用HPLC法测定了东北大豆、黄淮大豆及美国转基因大豆中α、β、γ、δ-生育酚的含量。从所得数据的统计结果来看,东北大豆的α、β-生育酚含量显著高于进口的美国转基因大豆和黄淮大豆,而美国转基因大豆在γ-生育酚含量和生育酚总量方面高于东北大豆和黄淮大豆。东北大豆是生产高质量生育酚(维生素E)的优质资源。     

高效液相色谱法测定保健食品中三氯蔗糖的含量

目的建立一种保健食品中三氯蔗糖含量测定的高效液相色谱检测法。方法样品采用Rad pak C18色谱柱(4.6 mm×250 mm,5μm)进行分离,以1.0 m L/min乙腈:水(V:V=15:85)为流动相,最后用高效液相色谱法(HPLC)-示差折光仪为检测器进行测定,外标法定量分析。结果高效液相色谱法在0.482~2.892 mg/m L浓度范围,三氯蔗糖的浓度和峰面积的线性良好,相关系数为0.999(r0.99),该方法的检出限和定量限分别为19.58 mg/g和65.27 mg/g,在不同的添加水平下,该方法的回收率范围为95.0%~95.6%,相对标准偏差为0.3%(n=9)。结论高效液相色谱法灵敏度、准确度均较高,适用于保健食品中三氯蔗糖的含量测定。     

燕麦发芽过程中酚类物质的变化

对燕麦种子进行发芽实验,并分析酚类物质在发芽过程中的含量、组成及抗氧化活性变化。结果表明：燕麦发芽过程中,酚类物质的含量明显提高,且芽和根中总酚的相对含量高于籽粒;发芽前后不同部位多酚的组成不同,从而导致其抗氧化活性存在差异。抗氧化实验结果显示：原样、6d籽粒、6d芽和6d根的多酚提取物具有较强的还原力(EC50值分别为86.47、61.96、98.54μg/mL和51.98μg/mL)和清除DPPH自由基(IC50值分别为26.90、15.43、30.71μg/mL和21.30μg/mL)及NO2－( IC50值分别为0.653、0.441、1.353mg/mL和0.227mg/mL)的能力,且发芽可以作为一种提高燕麦利用价值的有效手段。     

高效液相色谱法测定黑米提取物中矢车菊色素的成分及含量

利用高效液相色谱法测定黑米提取物的主要成分及含量。采用岛津VP-ODSC18柱(4.6mm×150mm)色谱柱,以磷酸(4%水溶液)∶乙腈(v∶v=8.8∶1.2,pH=2.0)为流动相,流速为0.8mL/min,柱温30℃,检测波长520nm。实验结果表明:该黑米提取物主要成分是矢车菊素-3-葡萄糖苷,平均含量为41.8479%。     

不同红茶中主要氨基酸含量及其对小鼠自主活动的影响研究

通过高效液相色谱法（HPLC）测定不同红茶中γ-氨基丁酸（γ-aminobutyric acid,GABA）、L-茶氨酸和L-谷氨酸的含量,并通过小鼠自主活动测试仪比较不同主要氨基酸含量的红茶水提物对小鼠自主活动的影响。结果表明,不同红茶中GABA、L-茶氨酸和L-谷氨酸含量差别均较大,并且L-茶氨酸含量普遍高于GABA、L-谷氨酸含量。其中,GABA含量以高黎贡山为最高,汉水韵红茶次之,紫鹃红最低;L-茶氨酸和L-谷氨酸含量均以八仙红茶为最高,汉水韵红茶次之,印度大吉岭红茶最低。此外,动物实验结果显示,与主要氨基酸含量较低红茶组相比,主要氨基酸含量较高红茶组小鼠的自主活动次数显著减少（p<0.05）。以上结果提示,主要氨基酸含量较高的红茶对小鼠具有明显的镇静作用。      

生食金枪鱼行业标准解读

为全面推广金枪鱼产品,发展我国远洋渔业,农业部曾于2006年发布水产行业标准SC/T 3117-2006《生食金枪鱼》。随着生食金枪鱼加工业的不断发展,SC/T 3117-2006《生食金枪鱼》规定的部分指标已不符合产业实际,为有效规范生食金枪鱼产品的生产和保障产品质量,2016年农业部下达任务由中国水产科学研究院黄海水产研究所承担生食金枪鱼标准的修订工作。本研究在介绍新标准SC/T 3117-2006《生食金枪鱼》基本框架的基础上,阐述了中心温度、一氧化碳和挥发性盐基氮等主要技术指标的确立依据,还对比了标准修订前后的主要变化内容。本研究将为质量监管部门和生食金枪鱼生产企业正确理解和执行标准提供理论依据和技术参考。     

Starch,protein, glycoalkaloids,and <Emphasis Type="SmallCaps">l</Emphasis>-ascorbic acid content in tubers of genetically modified potato cv. Irga

Changes in contents of protein, starch, ash, l-ascorbic acid, and glycoalkaloids in tubers of 15 clones of cultivar Irga transformed with viral genome sequences in order to improve their resistance to a necrotic strain of potato virus Y (PVY^N) were investigated. The influence of modification type and year of cultivation on the contents of all chemical compounds examined for particular modified clones appeared to be irregular over the 3-year period of examination, and the clone of the best and stable content of chemical compounds was not found. Stable tendencies in the chemical compounds of tubers composed into groups and subgroups of clones representing the same modification type were not confirmed either. An essential stable decrease in glycoalkaloid content and an increase in starch content (compared with parental cultivar Irga) were found in almost all genetically modified clones. Glycoalkaloid content in green tubers of modified clones was usually (except three clones) higher than this for parental cultivar Irga. Correlation between glycoalkaloid content and tuber size for all, normal and green tubers of selected clones and parental cultivar Irga was examined as well.