糖型与淀粉型木薯后代块根品质与发酵特性

为了研究糖型与淀粉型木薯后代块根品质与发酵特性,测定了28个木薯品系块根的干物质、淀粉、总糖、还原糖、粗蛋白和灰分等主要品质性状。结果表明,淀粉型木薯后代块根的淀粉（14.52%）、总糖（27.48%）、干物质（41.24%）、粗蛋白（1.67%）和灰分（0.25%）含量,总体上比糖型木薯后代块根高;糖型木薯后代块根还原糖含量（2.01%）显著高于淀粉型木薯后代块根（0.61%）（P＜0.05）,而其淀粉含量仅6.62%。相关分析表明,还原糖与淀粉、总糖、干物质和粗蛋白等性状均呈显著负相关（P＜0.05）。通过杂交改良克服负相关,新品系SM03块根的乙醇转化率达到53.7 mL/100 g干质量,产酒精34.73 L/hm2。SM03和SC16只糖化、不经过糊化预处理,酵母发酵分别产酒精31.13 L/hm2、27.80 L/hm2,均是很有推广价值的能源木薯新品种。     

全自动蒸馏-流动分析仪联用测定木薯粉中氰化物

为更加高效地测定食品中的氰化物,该试验建立全自动智能化水蒸气蒸馏仪（automatic intelligent steam distillation,AISD）和氰化物连续流动分析仪联用法测定木薯粉中氰化物含量的方法。结果表明：在0～200μg/L的氰化物浓度范围内,该方法线性度良好,相关系数为0.999 5。当选择样品为5 g、蒸馏后定容体积为50 m L时,木薯粉样品中氰化物的方法检出限（信噪比S/N=3）为0.013 mg/kg,定量限（信噪比S/N=10）为0.043 mg/kg。该方法精密度（relative standard deviation,RSD）为2.5%～6.7%,加标回收率为93.72%～103.33%。与GB 5009.36—2016《食品安全国家标准食品中氰化物的测定》中的第一法进行对比,配对t检验的结果为t=2.233 27,p=0.075 85(p>0.05),说明在0.05水平下,该方法与GB 5009.36—2016没有显著性差异。该方法重复性好、准确度高、分析速度快、耗时短。因此,可以用于批量检测木薯粉中氰化物。     

不同菌种发酵木薯粉品质和糊化特性比较分析

以华南9号木薯（SC9）块根为原料,利用5个菌种进行发酵,比较分析发酵前后木薯粉常规营养品质、有机酸风味物质组成和结构特性等差异。结果表明,酿酒酵母（Saccharomyces cerevisiae）发酵显著提高（P<0.05）木薯粉的蛋白质含量,比对照组提高2.2倍,达0.83 g/100 g;而许旺酵母（Schwanniomyces occidentalis Kl?cker）发酵可显著降低氰化物含量（P<0.05）,降解率达91.82%;枯草芽孢杆菌（Bacillus subtilis）发酵后有机酸含量最高,达到10.987 mg/g,并显著提高了粗多糖得率（P<0.05）,达到1.59%。从加工特性看,枯草芽孢杆菌发酵后,糊化特性的峰值黏度、谷值黏度、最终黏度均显著提高（P<0.05）分别为5 397.5、3 439.0、4 770.0 mPa·s,衰减值显著降低（P<0.05）,为1 958.5 mPa·s。结构特性分析表明,发酵后木薯粉淀粉颗粒均匀,显著变小。综合对比,利用枯草芽孢杆菌发酵木薯粉,有利于提高木薯粉的脂肪、有机酸、粗多糖等营养品质并...     

木薯茎杆基质比例对3 种食用菌海藻糖含量的影响

以木薯茎杆栽培的食用菌为试材,对海藻糖的提取方法和高效液相色谱-蒸发光散射（high performanceliquid chromatography-evaporative light scattering detector,HPLC-ELSD）检测方法进行优化,分析不同比例木薯茎秆栽培3 种食用菌（黑木耳、平菇、榆黄蘑）海藻糖含量。结果表明,食用菌中的海藻糖在80 ℃水浴60 min条件下可有效提取,最高含量达到190.5 mg/g;利用优化后色谱条件分析标准品和样品中海藻糖,其分离效果均良好。并分析黑木耳、平菇和榆黄蘑中海藻糖含量,发现当栽培基质的木薯茎秆比例为31.2%时,3 种食用菌海藻糖含量较高,分别为61.5、250.3 mg/g和15.0 mg/g。结果表明,HPLC-ELSD可分析3 种食用菌中海藻糖含量,方法准确度高、重复性好、样品稳定性较好;3 种食用菌海藻糖含量与培养基质中木薯茎秆比例有关,合适的木薯茎秆比例可提高食用菌中海藻糖含量。     

影响木薯蚕蛹食用安全性的成分分析

采用原子荧光法和滴定法分析影响木薯蚕蛹食用安全性的成分。结果表明：木薯蚕蛹中总砷含量（1.99±0.84）mg/kg、铅含量（0.14±0.03）mg/kg、镉含量（0.54±0.14）μg/kg、汞含量未检出。木薯蚕蛹中氰化物的含量为（0.33±0.07）mg/kg干样,经过水煮、蒸、油炸、微波处理后,其氰化物的清除率分别达到100%、78.83%、26.78%和39.37%。木薯蚕蛹挥发性盐基氮（TVB-N）值达到（71.62±5.32）mg/100 g。说明木薯蚕蛹铅、镉、汞和氰化物的含量远低于相关规定的限值。     

湘葛一号茎叶中5 种异黄酮成分的高效液相色谱法定量分析

建立高效液相色谱法同时测定湘葛一号地上部分中5 种异黄酮成分含量的方法。采用AT·LICHROM C18
色谱柱（4.6 mm×250 mm,5 μm）,以甲醇-水为流动相进行梯度洗脱,流速1.0 mL/min,检测波长250 nm,
柱温30 ℃。葛根素、大豆苷、染料木苷、大豆苷元和染料木素分别在5.00～50.00（r=0.999 4）、1.00～10.00
（r=0.999 2）、3.64～36.40（r=0.999 9）、0.50～5.00 μg/mL（r=0.999 8）和0.10～1.00 μg/mL（r=0.999 4）范围
内线性良好,检测限分别为0.94、0.24、0.43、0.08 ng/L和0.05 ng/L,定量限分别为2.85、0.73、1.29、0.25 ng/L
和0.15 ng/L。精密度、稳定性和重复性良好,平均回收率分别为100.11%（相对标准偏差（RSD）为1.39%）、
99.54%（RSD为1.47%）、98.06%（RSD为0.32%）、101.52%（RSD为1.89%）和101.05%（RSD为0.32%）。该方
法快速、准确,操作简单,可用于湘葛一号地上部分5 种异黄酮成分含量的同时测定。     

橡胶籽粕黑曲霉固态发酵脱氰研究

利用黑曲霉固态发酵降解橡胶籽粕中的亚麻苦苷脱氰。在单因素试验的基础上,以发酵时间、发酵温度和麸皮添加量为自变量,以氰脱除率为响应值,进行橡胶籽粕黑曲霉固态发酵脱氰响应面优化试验。得到的最佳脱氰工艺条件为：发酵时间82 h,发酵温度30.5℃,麸皮添加量11 g（10 g橡胶籽粕）。在最佳条件下,氰的脱除率为94.30%,经发酵的橡胶籽粕氰含量由3.7 mg/kg降至0.211 mg/kg。     

细度对食用木薯粉理化品质和消化特性的影响

以食用木薯粉为主要研究对象,研究不同细度食用木薯粉理化品质、加工特性、消化和热分解特性。结果表明:不同细度食用木薯粉的淀粉含量和粗蛋白含量达显著差异,其中80目的蛋白质含量最高;而溶胀度、可溶性分别与细度呈负相关和正相关关系;从热分解特性看,不同细度食用木薯粉DSC曲线具有两个峰值温度,而80目食用木薯粉焓变最大,达到-882.88 kJ/kg,热稳定性差。进一步研究其消化特性发现,食用木薯粉细度越大,其快速消化淀粉(RDS)含量越高,但慢消化淀粉(SDS)含量则相反。相关分析表明,粗蛋白含量分别与RDS、SDS呈极显著负相关(-0.740 71)和正相关(0.866 28)。细度不仅显著影响木薯粉的稳定性,还决定木薯粉的消化性能。     

木薯酒发酵过程中的有机酸变化及对其品质的影响分析

以新鲜甜木薯为原料,跟踪监测木薯酒发酵过程中的理化指标,并采用高效液相色谱法分析木薯酒发酵期间的有机酸组成及动态变化情况,进一步分析酒发酵过程中的酸味强度。结果表明,发酵过程中,木薯酒中的还原糖含量先快速上升至最高点最后趋于平稳（54.67 mg/mL）;酒精度先上升后平稳（7.11%vol）;总酸含量先缓慢减少至2.21 mg/mL,再缓慢增加,后快速增加,与pH值变化趋势相反。酒石酸、乳酸、乙酸、柠檬酸、琥珀酸是木薯酒发酵中重要有机酸,分别占木薯酒总有机酸含量的2.66%～12.31%,41.50%～63.53%,18.21%～23.82%,1.22%～27.77%,3.17%～15.89%,其他有机酸是酒中的辅助酸味特征成分。乳酸和乙酸是木薯酒的主体酸,其味道强度值（TAV）占总TAV值的65.82%～95.84%,发酵84 h的木薯酒有最高的味道强度值,其可达到223.87。     

食用木薯块根冻结特性及代谢产物分析

为了解木薯块根冻结特性及其代谢产物,以食用木薯品种“华南9号”为研究对象,通过电导率法测定块根头、中和尾3个部位的冻结变化规律及相关影响因素,结合非靶向代谢组学进行差异代谢物分析。结果表明:木薯块根不同部位冰点范围为?0.6至?1.1 ℃,但发生冻结的时间不一致;不同部位的可溶性固形物含量与淀粉含量最高值均出现在头部,分别为7.00%和26.84%,但各部位间的含量差异不显著（P>0.05）,而含水量最高值出现在尾部,为64.07%;相关性结果分析发现,冰点与可溶性固形物、含水量呈负相关关系,与淀粉含量呈正相关关系。非靶向代谢组学分析发现,与对照相比冰温处理存在41个具有显著差异表达的代谢物,以苯丙氨酸代谢途径富集程度最高,共有9个显著差异代谢物。该途径中马尿酸-苯甲酸-水杨酸通路的马尿酸、苯甲酸表达上调,这可能与块根对低温应答响应有关。该研究结果可为今后木薯块根低温贮藏提供理论参考。     

Application of a picrate semi‐quantitative screening assay for the cyanogenic potential of cassava roots at a remote field site

The purpose of this research was to test the accuracy of the picrate screening assay (PSA) in the evaluation of the cyanogenic potential of cassava roots at a remote field site under conditions of unusual difficulty. To do this, a PSA was conducted in the field and compared to data collected previously on five of the same cassava varieties using the Cooke colorimetric enzymic assay. PSA data were collected for 10 different cassava varieties in the Tukanoan Indian village of Yapú in the Colombian Amazon region. The PSA results agree with Tukanoan classifications of cassava; that is, those classified as ‘sweet’ by the Tukanoans generally had low‐to‐moderate parenchymal cyanogenic potential (0–50 mg kg⁻¹ fwb of HCN), while those that they classify as ‘bitter’ had high parenchymal cyanogenic potential (≥100 mg kg⁻¹ fwb of HCN). The PSA results also agree with the data collected using the Cooke colorimetric enzymic assay. The data suggest that the PSA is an appropriate test of the cyanogenic potential of cassava roots in remote field sites. © 2000 Society of Chemical Industry     

The retail market for fresh cassava root tubers in the European Union (EU): the case of Copenhagen,Denmark — a chemical food safety issue?

BACKGROUND: A number of retail shops in Copenhagen sell fresh cassava roots. Cassava roots contain the toxic cyanogenic glucoside linamarin. A survey was made of the shop characteristics, origin of the roots, buyers, shop owner's knowledge of toxicity levels, and actual toxicity levels. RESULTS: Shops selling fresh cassava were shown mostly to be owned by persons originating in the Middle East or Afghanistan, buyers were found to predominantly be of African origin, and sellers' knowledge concerning the potential toxicity was found to be very restricted. Seventy‐six per cent of the roots purchased had a total cyanogenic potentials (CNp) above the 50 mg HCN equivalents kg^?1 dry weight (d.w.) proposed as acceptable by an EU working group. Two of 25 roots purchased had CNp higher than 340 mg HCN eq. kg^?1 d.w. CONCLUSION: The EU has previously made risk assessments concerning cassava and cyanogenic compounds. In the light of the conclusions drawn, the EU needs to make decisions about how to deal with the regulation and control of fresh cassava roots imported to the European food market. Also cassava root products and cassava leaves should be considered. Copyright © 2009 Society of Chemical Industry     

Cyanogenic potential of randomly sampled fresh and processed cassava on retail sale in Singapore

A random sample of fresh cassava roots and cassava products, purchased at various retail outlets in Singapore during 2016–2017, had total cyanogenic potential (CNp–expressed as mean ± standard deviation, mg kg⁻¹ HCN, fresh weight basis) as follows: fresh roots (n = 66) from three SE Asian countries, 59.0 ± 19.2; peeled chilled root pieces from Malaysia (20 × 1-kg packs), 38.5 ± 16.5; cassava flour from Indonesia (8 × 1-kg packs), 11.7 ± 8.2; dried Indonesian chips for home frying (5 × 250 g packs), 61.6 ± 16.5; one pack (120 g) of Malaysian ready-to-eat (RTE) chips, 17.1 ± 3.2. CNp in all flour and RTE chips was below 20 mg kg⁻¹. The majority of fresh roots (59.1%) and packs of dried chips (80%), and 15% of packs of peeled chilled root parenchyma, exceeded the Codex Alimentarius limit (50 mg kg⁻¹) for ‘sweet’ (boil-and-eat) cassava.     

Mycotoxins and cyanogenic glycosides in staple foods of three indigenous people of the Colombian Amazon

A study was conducted to determine the incidence and levels of mycotoxins in the main staple foods of three indigenous people of the Colombian Amazon. A total of 20 corn, 24 rice and 59 cassava samples were analysed by a multi-analyte liquid chromatography-tandem mass spectrometry method covering the major classes of mycotoxins. In addition, cassava samples were also analysed for cyanogenic glycosides. The indigenous Amazon communities tested are exposed to potentially carcinogenic mycotoxins (particularly aflatoxins), as well as other mycotoxins, mainly through the intake of locally grown corn. Citrinin content in this corn was unusually high and has not been reported elsewhere. Two cassava samples contained high levels of cyanogenic glycosides. It is strongly recommended not to grow corn in the Amazon but instead purchase it from vendors capable of guaranteeing mycotoxin levels below the maximum allowable concentration in Colombia.     

Rising African cassava production,diseases due to high cyanide intake and control measures

Cassava is the staple food of tropical Africa and its production, averaged over 24 countries, has increased more than threefold from 1980 to 2005, and the population has more than doubled over that time compared with a 1.5 times increase worldwide. Agriculturally, cassava performs very well but the roots and leaves contain cyanogenic glucosides that are dangerous to human health. These cyanogens sometimes produce acute intoxication leading to death, they exacerbate goitre and cretinism in iodine‐deficient regions, cause konzo and are implicated in the occurrence of tropical ataxic neuropathy and stunting of children. Konzo is an irreversible paralysis of the legs with many thousands of cases, mainly amongst children, in Mozambique, Tanzania, Democratic Republic of Congo, Cameroon, Central African Republic and probably other tropical African countries. Attempts to alleviate cassava cyanide toxicity have included the development of an information network and distribution in developing countries of picrate kits, which measure total cyanide in cassava and urinary thiocyanate. A simple wetting method that reduces total cyanide in cassava flour three‐ to sixfold has been successfully field tested and is being introduced in Mozambique. Transgenic technology shows promise in increasing the rate of loss of cyanide from roots during processing. World health and agricultural bodies should pay more attention to emerging health problems associated with toxicity of cyanogens in cassava. Copyright © 2008 Society of Chemical Industry     

ICP-MS法测定市售红薯粉条中铝和钛

采用电感耦合等离子体质谱仪(ICP-MS,Inductively Coupled Plasma Mass Spectrometry)测定红薯粉条中的铝和钛。样品经微波消解后,以钪(45Sc)为内标物,用ICP-MS同时测定铝和钛。红薯粉条中铝元素的检测浓度线性范围为0~80 ng/mL(R2=0.9993),加标回收率为82.2%~95.5%,相对标准偏差为0.7%~1.7%,检出限为0.01 mg/kg,定量限为0.03 mg/kg;钛元素的检测浓度线性范围为0~50 ng/mL(R2=1.0000),加标回收率为86.3%~93.2%,相对标准偏差为0.3%~1.3%,检出限为0.01 mg/kg,定量限为0.02 mg/kg。8 h稳定性实验中铝、钛的RSD分别为4.67%、9.12%;重复性实验中,铝、钛的RSD分别为2.04%、1.97%。该方法操作简单、灵敏度高、线性范围广、定量准确,适合测定红薯粉中的铝和钛,为科学地评价红薯粉中铝和钛含量提供数据参考。     

Retention of carotenoids in cassava roots submitted to different processing methods

Large genetic variation in carotenoid content has been reported after screening roots from thousands of cassava genotypes. Moreover, these pigments have to withstand different processing methods before cassava is consumed. True retention of β‐carotene from cassava roots that had been boiled, oven‐dried, sun‐dried, shadow‐dried, or used for gari preparation was measured. True retention was also measured after storing for 2 or 4 weeks some of the products of these processing methods. Oven‐drying, shadow drying and boiling retained the highest levels of β‐carotene (71.9, 59.2 and 55.7%, respectively) and gari the lowest (about 34.1%). Higher retention was observed when dried roots were kept as chips rather than as flour. Storage of flour packed in plastic bags under vacuum unexpectedly resulted in higher losses than storage of flour packed in plastic bags without the application of vacuum. Losses were higher during the first 2 weeks and tended to be considerably lower during the second 2 weeks of storage. Copyright © 2006 Society of Chemical Industry     

Cyanogenicity of cassava varieties and risk of exposure to cyanide from cassava food in Nigerian communities

BACKGROUND: High‐cyanogenic cassava varieties are cultivated in many tropical communities that are free of neurological syndromes attributed to consumption of cassava foods. This study was done in four geographical areas of Nigeria (northern, southwestern, southeastern and an area endemic for ataxic polyneuropathy) to determine if cyanogenicity of cassava is associated with geographical area, altitude or level of cyanogenic compounds in gari, a popular cassava food in West Africa. RESULTS: Mean levels of cassava cyanogens were 153, 127, 68 and 65 mg HCN equivalents (eq.) kg^?1 dry weight (DW) in the endemic, southeastern, southwestern and northern areas respectively (P < 0.0001), while mean levels of gari cyanogens were 9, 4, 7 and 13 mg HCN eq. kg^?1 DW in the respective areas (P < 0.0001). The mean altitude was 35 m in the endemic area, 55 m in the southeastern area, 220 m in the southwestern area and 273 m in the northern area (P < 0.0001). Altitude was associated with cyanogenicity of cassava in univariate and multivariate models (P < 0.0001). One hundred and twenty‐six (93%) farmers and 255 (77%) processors did not perceive cassava or its food products as toxic. CONCLUSION: The findings indicate that cyanogenicity of cassava is determined by environmental factors rather than by conscious selection of varieties by farmers. Farming high‐cyanogenic cassava is not associated with high levels of residual cyanogens in gari. Cassava is not perceived as toxic by farmers and processors. Copyright © 2008 Society of Chemical Industry     

面制品中过氧化苯甲酰和苯甲酸的测定及热稳性研究

建立一种同时测定面制品中过氧化苯甲酰(BPO)和苯甲酸(BA)的高效液相色谱法,采用液氮冷冻干燥,将面制品预处理后采用无水乙醇进行提取BPO及BA后,用Tech Mate C_(18)色谱柱(5μm,250 mm×4.6 mm),以乙腈-乙酸(pH2.8)水溶液等度洗脱,检测波长233 nm,该方法在0.05~200mg/L范围内具有良好的线性特征(R_(BPO)=0.99987,R_(BA)=0.99994)。通过基质加标,BPO回收率介于90.2%~96.5%之间,相对标准偏差介于1.5%~3.4%之间,BA回收率介于91.5%~101.3%之间,相对标准偏差介于1.1%~3.6%之间,LODBA值为0.5 mg/kg,LOD_(BPO)值为0.8 mg/kg,说明该方法可行。同时,模拟样品在煮沸情况下BPO和BA的变化情况,得出BPO热稳性较差,在一定条件下分解产生BA。     

木薯全粉对饼干储藏期品质和质构特性的影响

研究了木薯全粉对饼干储藏期品质和质构特性的影响,以不同比例木薯全粉替代低筋面粉制作饼干,对其理化和质构指标进行评价。结果表明:添加木薯全粉使得饼干的明亮度下降,色泽变黄。木薯全粉可降低储藏期饼干的水分含量和吸水率,提高脆性。其中,木薯全粉与低筋面粉比例为30/70时,饼干在储藏期内水分含量、咀嚼性和硬度最低,脆性最高。当木薯全粉与低筋面粉的比例大于40/60时,与对照组相比,饼干的硬度、弹性和咀嚼性升高,饼干的品质下降。