Reduction of fumonisin B₁ in corn grits by twin-screw extrusion

Abstract: This study was designed to investigate the fate of fumonisins in flaking corn grits during twin‐screw extrusion by measuring fumonisin B₁ (FB₁) and its analogs with a mass balance approach. Food grade corn grits and 2 batches of grits contaminated with FB₁ at 10 and 50 μg/g by Fusarium verticillioides M‐2552 were processed with or without glucose supplementation (10%, w/w) with a twin‐screw extruder. Extrusion reduced FB₁ in contaminated grits by 64% to 72% without glucose and 89% to 94% with added glucose. In addition, extrusion alone resulted in 26% to 73% reduction in the levels of fumonisin B₂ and fumonisin B₃, while levels of both mycotoxins were reduced by >89% in extruded corn grits containing 10% glucose. Mass balance analysis showed that 38% to 46% of the FB₁ species detected in corn extruded with glucose was N‐(deoxy‐D‐fructos‐1‐yl)‐FB₁, while 23% to 37% of FB₁ species detected in extruded corn grits with and without added glucose was bound to the matrix. It was also found that the hydrolyzed form of FB₁ was a minor species in extruded corn grits with or without added glucose, representing <15% of the total FB₁ species present. Less than 46% of FB₁ originally present in corn grits could be detected in the fumonisin analogues measured in this study. Research is needed to identify the reaction products resulting from extrusion processing of fumonisin‐contaminated corn products. Practical Application: Twin‐screw extrusion is widely used in food industry for its versatility. This technology may reduce the level of fumonisins in corn particularly with added glucose.     

Stability of mycotoxins during food processing

The mycotoxins that commonly occur in cereal grains and other products are not completely destroyed during food processing operations and can contaminate finished processed foods. The mycotoxins most commonly associated with cereal grains are aflatoxins, ochratoxin A, fumonisins, deoxynivalenol and zearalenone. The various food processes that may have effects on mycotoxins include sorting, trimming, cleaning, milling, brewing, cooking, baking, frying, roasting, canning, flaking, alkaline cooking, nixtamalization, and extrusion. Most of the food processes have variable effects on mycotoxins, with those that utilize the highest temperatures having greatest effects. In general the processes reduce mycotoxin concentrations significantly, but do not eliminate them completely. However, roasting and extrusion processing show promise for lowering mycotoxin concentrations, though very high temperatures are needed to bring about much of a reduction in mycotoxin concentrations. Extrusion processing at temperatures greater than 150 degrees C are needed to give good reduction of zearalenone, moderate reduction of alfatoxins, variable to low reduction of deoxynivalenol and good reduction of fumonisins. The greatest reductions of fumonisins occur at extrusion temperatures of 160 degrees C or higher and in the presence of glucose. Extrusion of fumonisin contaminated corn grits with 10% added glucose resulted in 75-85% reduction in Fumonisin B(1) levels. Some fumonisin degredation products are formed during extrusion, including small amounts of hydrolyzed Fumonisin B(1) and N-(Carboxymethyl) - Fumonisin B(1) and somewhat higher amounts of N-(1-deoxy-d-fructos-1-yl) Fumonisin B(1) in extruded grits containing added glucose. Feeding trial toxicity tests in rats with extruded fumonisin contaminated corn grits show some reduction in toxicity of grits extruded with glucose.     

Loss of Fuminosin B1 in Extruded and Baked Corn-Based Foods with Sugars

The objective of this work was to determine the effect of added sugars on fumonisin B₁ (FB₁) levels in baked corn muffins and extruded corn grits. Muffins containing added glucose had significantly lower FB₁ levels than muffins with sucrose, fructose, or no added sugar. Extrusion cooking of the grits resulted in significant (p< 0.05) reductions of FB₁ in all treatments relative to unextruded controls, but use of glucose resulted in greater reductions of FB₁ (45.3 to 71%) than did the use of fructose (29.5 to 53%) or sucrose (19.2 to 39%). When extrusion conditions were optimized, 92.1% loss of FB₁ was found when grits were extruded with glucose. Adding glucose to thermally processed food can result in a substantial reduction in FB₁ levels.     

Occurrence of fumonisins and moniliformin in corn and corn-based food products of U.S. origin

Food-grade corn and corn-based food products intended for human consumption were analyzed for the incidence and levels of fumonisin B1 (FB1), fumonisin B2 (FB2), moniliformin, and Fusarium molds. A total of 100 food-grade commercial corn samples were obtained from two corn processing companies at five different locations in the United States. Seventy-one percent of the samples contained FB1 with concentrations ranging from 43 to 1,642 microg/kg. None of the samples contained FB2. Fifty percent of the samples contained moniliformin with concentrations ranging from 26 to 774 microg/kg. All samples were infected by Fusarium molds, and the infection rates ranged from 8 to 88%. Thirty-four samples of corn-based food products were purchased from supermarkets in Arizona, California, Nebraska, and Ohio. Sixty-five percent of the samples contained FB1, ranging in concentrations from 28 to 2,679 microg/kg. FB2 was detected in 29% of the samples with concentrations ranging from 30 to 797 microg/kg. Sixty-eight percent of the samples contained moniliformin with concentrations ranging from 31 to 858 microg/kg. Sixty-two percent of the samples contained viable Fusarium mold propagules ranging from 9.5 x 10(1) to 5.5 x 10(5)/g. The simultaneous occurrence of FB1 and moniliformin was observed in 34% of corn samples and 53% of corn-based food products. This study has shown co-occurrence of fumonisins and moniliformin in food-grade corn and corn-based foods that indicates a risk of simultaneous exposure of consumers to both toxins.     

Investigations on the change of fumonisin content of maize during hydrothermal treatment of maize. Analysis by means of HPLC methods and ELISA

The study was subjected to the investigation of the effects of extrusion cooking, gelatinization, and cornflaking on the stability of fumonisins in artificially contaminated maize grits, spiked with fumonisin B₁ and B₂ at levels of 2 mg/kg and 0.6 mg/kg, respectively. All the processed samples were analyzed according to the AOAC-HPLC method, and some selected samples were analyzed additionally by a commercial enzyme-linked immunosorbent assay (ELISA) and after alkaline hydrolysis. All the samples showed significant decreases of the fumonisin levels. If analyzed according to AOAC-HPLC method, cooking extrusion and gelatinization reduced fumonisin levels to approximately 30-55%, cooking the grits for flaking to approximately 20-65%, and roasting the flakes to approximately 6-35% (depending on the selected technological parameters). With ELISA the fumonisin contents were 15-50% and after alkaline hydrolysis 19-380% higher than with the AOAC-HPLC method. However, the fumonisin amount added before the technological tests could not be recovered in any of the samples.     

Study of fumonisins B1 and B2 contamination of baby food

Fumonisins content were studied in the baby foods, grits and flour by HPLC. FB1 +FB2 were found in 95% of 129 samples of grits and flour in quantities from 30 to 4350 microg/kg (mean: 580 microg/kg). Fumonisins were found in baby food in 52% of snacks in the range from 10 to 720 microg/kg (mean: 35 microg/kg). Processed cereal-based and cereal and dairy-based food contained FB1+FB2 in 39% of cases in the amount from 10 to 9200 microg/kg (mean: 244 microg/kg). Fumonisins were not found in canned baby food on the cereal-based with meat, fish or fruit products.     

Fusaria and fumonisins in maize from Ghana and their co-occurrence with aflatoxins

Fifteen maize samples from four markets and processing sites in Accra, Ghana were analysed for fumonisins B1, B2, and B3. All samples contained fumonisins. Total fumonisin levels for 14 samples ranged from 70 to 4222 microg kg(-1). One sample of visibly mouldy kernels contained 52 670 microg kg(-1) total fumonisins. Mycological examination of the samples showed Aspergillus spp. as the most dominant fungi (76.4%) followed by Penicillium spp. (19.9%). Fusarium formed 2.6% with Fusarium verticillioides as the predominant Fusarium species. Thirty-two Fusarium strains representing five species isolated from the maize samples were tested for the production of fumonisins in maize substrates. From 95% (21 of 22) of the F. verticillioides strains tested, all three types of fumonisins were produced. Total fumonisin levels ranged from 127 to 11 052 microg g(-1). Additional studies on maize samples from 15 processing sites in Accra revealed a co-occurrence of both fumonisins and aflatoxins in 53% (8 of 15) of the samples.     

Stability of zearalenone during extrusion of corn grits

The effects of extrusion cooking on the stability of zearalenone (ZEN) in spiked (4.4 microg/g) food-grade corn grits were investigated using a twin screw extruder. A ground rice culture material containing a high level of ZEN was used to spike the corn grits. The extrusion variables were screw type (mixing and nonmixing), temperature (120, 140, and 160 degrees C), and moisture content (18, 22, and 26%). Both unextruded and extruded samples were analyzed for ZEN by high-performance liquid chromatography. Extrusion cooking of the corn grits resulted in significant reductions of ZEN in grits extruded with either mixing screws or nonmixing screws, but use of mixing screws was somewhat more effective (66 to 83%) overall than nonmixing screws (65 to 77%). Greater reduction of ZEN was observed at either 120 or 140 degrees C than at 160 degrees C. The moisture content of corn grits was not a significant factor affecting reduction of ZEN during extrusion with either mixing or nonmixing screws.     

Occurrence of aflatoxins and fumonisins in Incaparina from Guatemala.

The occurrence of aflatoxins and fumonisins in Incaparina was investigated. Incaparina is a mixture of corn and cottonseed flour with added vitamins, minerals and a preservative. It has been marketed as a high-protein food supplement, particularly for children on protein-deficient diets. According to estimates, 80% of Guatemalan children in their first year are given Incaparina to provide an adequate diet. Eight samples of Incaparina manufactured in Guatemala were collected. Five were from three different geographical locations in the USA and three were from Guatemala. Seven were examined for fungal contamination and analysed for aflatoxins and fumonisins. Aspergillus flavus was the predominant fungus in all samples purchased in the USA and in one sample purchased from Guatemala, whereas Fusarium verticillioides was present in only two samples (one from the USA and one from Guatemala). All samples contained aflatoxins, ranging from 3 to 214 ng g(-1) and <2 to 32ng g(-1) for aflatoxin B(1) and aflatoxin B(2), respectively; and one sample contained aflatoxin G(1) (7 ng g(-1)). Total aflatoxins present ranged from 3 to 244 ng g(1). All samples contained fumonisins, ranging from 0.2 to 1.7 microg g(-1), <0.1 to 0.6 microg g(-1), and <0.1 to 0.2 microg g(-1) for fumonisins B(1), fumonisin B(2), and fumonisin B(2), respectively. Total fumonisins present ranged from 0.2 to 2.2 microg g(-1). The identity of aflatoxin B(2) was confirmed using both the chemical derivatization method and liquid chromatographic (LC)/mass spectrometric (MS) analysis. Appropriate regulatory action was recommended for the import of Incaparina and has been in effect since 22 December 1998.     

Determination of fumonisins B1 and B2 in herbal tea and medicinal plants in Turkey by high-performance liquid chromatography

The purpose of this study was to measure the potential levels of fumonisin B1 (FB1) and fumonisin B2 (FB2) contamination in several herbal teas and medicinal plants that are consumed regularly in Turkey. FB1 and FB2 were detected using high-performance liquid chromatography with fluorescence detection after derivatization with o-phthaldialdehyde. A total of 115 commercially available herbal tea and medicinal plant samples were analyzed. The recoveries in black tea were 86.9+/-8.42% for FB1 and 102+/-6.80% for FB2 spiked with 1 microg/g of each analyte. Similarly, the mean recovery results in lime (linden) for FB1 and FB2 were 85.2+/-9.76% and 78.6+/-5.67%, respectively. The minimum detectable amounts for the o-phthaldialdehyde derivatives of FB1 and FB2 were 0.025 microg/g (1 ng injected) and 0.125 microg/g (5 ng), respectively. FB1 was detected in two samples (0.160 and 1.487 microg/g), and FB2 was detected in none of the samples.     

Reduction of Moniliformin in Corn by Heat Processing

The effects of autoclaving, baking, extrusion, frying, and roasting on the stability of moniliformin (MON) in spiked (5 μg/g of MON) corn‐based food products were investigated. Roasting corn meal at 218 °C for 15 min had the most significant effect (p ≤ 0.05) on the reduction of MON (44.6%). Autoclaving creamed corn at 121 °C for 65 min resulted in only 10% reduction of MON. Reductions of MON ranging from 5.4 to 28.9% were observed when corn chips were prepared from spiked masa. MON was reduced by 42.2% when corn muffins were baked and by 26.7% when corn grits were extruded. Overall, MON showed heat stability similar to or greater than other Fusarium mycotoxins such as deoxynivalenol and fumonisin B₁     

Occurrence of aflatoxins, ochratoxin A, and fumonisins in retail foods in Japan

We conducted a survey of aflatoxin B1, B2, G1, and G2, ochratoxin A, and fumonisin B1, B2, and B3 contamination in various foods on the retail market in Japan in 2004 and 2005. The mycotoxins were analyzed by high-performance liquid chromatography, liquid chromatography-mass spectrometry, or high-performance thin-layer chromatography. Aflatoxins were detected in 10 of 21 peanut butter samples; the highest concentration of aflatoxin B1 was 2.59 microg/kg. Aflatoxin contamination was not found in corn products, corn, peanuts, buckwheat flour, dried buckwheat noodles, rice, or sesame oil. Ochratoxin A was detected in oatmeal, wheat flour, rye, buckwheat flour, green coffee beans, roasted coffee beans, raisins, beer, and wine but not in rice or corn products. Ochratoxin A concentrations in contaminated samples were below 0.8 microg/kg. Fumonisins were detected in popcorn, frozen corn, corn flakes, and corn grits. The highest concentrations of fumonisins B1, B2, and B3 in these samples were 354.0, 94.0, and 64.0 microg/kg, respectively.     

利用燕麦麸脂肪模拟物制备的发酵香肠对大鼠脏器组织的影响

目的:本实验研究利用燕麦麸脂肪模拟物制备的发酵香肠(OBFS)与传统发酵香肠(TFS)对大鼠脏器组织的影响。方法:选取平均体重为(70±2)g的健康SD大鼠119只,随机分成7组,各组分别饲喂在基础饲料中添加0%的OBFS及TFS(对照组)、5% TFS、5% OBFS、10% TFS、10% OBFS、20% TFS、20% OBFS的饲料,在第9周时测定大鼠的脏体比、肝脏粗脂肪含量,并对肝脏病理切片进行观察。结果表明:与对照组相比,5%、10%、20% TFS组和5%、10%、20% OBFS组的心脏、肝脏、脾脏、肾脏、睾丸与体重的比值均无显著性差异(p>0.05);5%、10%、20% OBFS组的肝脏粗脂肪含量分别低于5%、10%、20% TFS组(p>0.05);病理切片结果显示,TFS添加量为5%、10%、20%和OBFS添加量为5%、10%时均对大鼠肝脏造成不同程度的损害,而OBFS添加量为20%时大鼠的肝脏形态正常。结论:发酵香肠不会造成大鼠心脏、肝脏、脾脏、肾脏和睾丸等脏器组织的损害,相比于TFS而言,OBFS具有预防脂肪肝形成的作用,且OBFS添加量为20%时,对大鼠肝脏基本无影响。     

Fumonisin B1 and hydrolyzed fumonisin B1 (AP1) in tortillas and nixtamalized corn (Zea mays L.) from two different geographic locations in Guatemala.

Fumonisin B1 (FB1) is a common contaminant of corn worldwide and is responsible for several diseases of animals. In the preparation of tortillas, corn is treated with lime (producing nixtamal) that when heated hydrolyzes at least a portion of the FB1 to the aminopentol backbone (AP1), another known toxin. This study analyzed the amounts of FB1 and AP1 in tortillas and nixtamal from two communities in the central highlands of Guatemala where corn is a major dietary staple (Santa Maria de Jesus, Sacatepequez, and Patzicia, Chimaltenango). The amounts of FB1 and AP1 in tortillas from Santa Maria de Jesus were, respectively, 0.85 +/- 2.0 and 26.1 +/- 38.5 microg/g dry weight (mean +/- SD), and from Patzicia were 2.2 +/- 3.6 and 5.7 +/- 9.4 microg/g dry weight. Less than 6% of the tortillas from both locations contained > or = 10 microg FB1/g dry weight; whereas, 66% of the samples from Santa Maria de Jesus and 29% from Patzicia contained > or = 10 microg AP1/g dry weight. The highest amount of AP1 (185 microg/g dry weight) was found in tortillas from Santa Maria de Jesus. The highest amounts of FB1 were 6.5 and 11.6 microg/g dry weight in tortillas from Santa Maria de Jesus and Patzicia, respectively. The mean concentration of FB1 in nixtamal was significantly higher in Santa Maria de Jesus compared to Patzicia. Surprisingly, AP1 was not detected in any of the nixtamal samples. The human impact of exposure to these amounts of fumonisins is not known. However, based on findings with other animals, where corn is a dietary staple, long-term consumption of FB1 and AP1 (especially at > or = 10 microg/g of the diet) may pose a risk to human health.     

Cadmium in caribou (Rangifer tarandus) kidneys: speciation, effects of preparation and toxicokinetics

Caribou kidney is a major source of cadmium (Cd) in the traditional diets of many aboriginal communities in the Arctic. In order to characterize the risk of Cd exposure, we studied the speciation of Cd in caribou kidneys and how it can be affected by food preparation. Cd in caribou kidneys was bound to metallothionein (MT) (40%), high molecular weight proteins (50-500 kDa) (30%) and existed as free ions (10%). There was no change in Cd concentrations after the samples were baked at 350°C for 30min but the MT level was significantly decreased. Food preparation also denatured the high molecular weight proteins, resulting in a significant increase of free Cd. The toxicokinetics of Cd in caribou kidney was studied using a rodent model. Four groups (n = 6) of adult Sprague-Dawley rats were fed with rat chow with the addition of one of the following: 10% veal kidney with 0 µg/g Cd, 10% veal kidney spiked with CdCl to make up to 66 µg/g Cd; 2 10% caribou kidney containing 20 µg/g Cd and 10% caribou kidney containing 66 µg/g Cd. After 14 days, Cd accumulation increased with dose but less than 1% of the dosed Cd accumulated in the liver and kidney of rats. The percentage of Cd accumulated in the liver was higher in the group fed with caribou kidney than that dosed with spiked veal kidney. Our results suggest that caribou kidney is a major source of Cd exposure among the Arctic populations but moderate consumption may be considered unavoidable.     

Distribution of fumonisins and aflatoxins in corn fractions during industrial cornflake processing

The aim of this study was to investigate the distribution of fumonisins (B(1) B(2,) and B(3)) and total aflatoxins (B(1), B(2), G(1), and G(2)) in various corn processed fractions. 92 batches of whole corn and derived dry-milled fractions (animal feed flour, flaking grits, corn flour and corn meal) and cooked and roasted cornflakes fractions were industrially obtained. Samples were analyzed for both groups of mycotoxins by enzyme-linked immunosorbent assay (ELISA). Dry milling of corn led to a heterogeneous distribution of the two groups of mycotoxins in the different parts of the grain, with increased levels in fractions processed from outer layers (animal feed flour and corn flour) and decreased levels in fractions processed from inner portions, such as corn meal and flaking grits. Levels of fumonisins in cornflakes were lower than 400 microg/kg, the maximum tolerable limit set by the EU. By contrast, three samples of final product were found to exceed the aflatoxin maximum tolerable limit of 4 microg/kg. Animal feed flour showed concentration factors of 317 and 288% for fumonisins and aflatoxins, respectively. Food traceability system was used by the industrial companies which processed corn into breakfast cereals. Nevertheless, even though the use of food traceability, which is defined as the ability to trace any food, feed, food-producing animal or substance that will be used for consumption through all stages of production, processing and distribution, only initial fumonisin contamination of whole corn and contamination of animal feed flour and corn flour were found to be correlated.     

天然非营养型甜味料发酵乳对四氧嘧啶诱导糖尿病模型大鼠糖代谢的影响

研究天然非营养型甜味料发酵乳对四氧嘧啶诱导糖尿病大鼠一般症状和血糖代谢的影响。添加天然非营养型甜味料、蔗糖及不添加甜味剂制备发酵乳并测定发酵乳感官和理化指标。采用四氧嘧啶腹腔注射诱导大鼠糖尿病模型,利用三种发酵乳灌胃干预4周,灌胃量为2 mL/100 g·bw·d,持续测量大鼠饮水、摄食量、体重和空腹血糖(GLU);测定糖化血红蛋白(HbA1c)、胰岛素(INS)、口服糖耐量(OGTT)。结果表明,使用天然非营养型甜味料与传统发酵乳在感官品质上无显著差异(p>0.05);灌胃4周后,各发酵乳大鼠血糖水平均恢复到20.20 mmol/L以下,胰岛素水平恢复到11.72 mIU/L以上,多饮多食和体重减轻等症状得到改善,其中利用甜味料制备的发酵乳效果更好,血糖值为18.80 mmol/L,胰岛素水平为13.85 mIU/L,口服糖耐量曲线下面积为42.30 h·mmol/L,糖化血红蛋白为10.53%,与阳性对照组(吡啶甲酸铬)无显著差异(p>0.05)。因而天然非营养型甜味料发酵乳具有一定的降糖活性。     

Preventive effect of sesame seed cake on hyperglycemia and obesity against high fructose-diet induced Type 2 diabetes in rats

The present study investigates the hypoglycemic and antiobesity effect of sesame seed cake (SSC) on rats fed with high fructose diet (HFD). SSC contained dietary fibre, lignans and phenolic compound. One month of HFD feeding induced significantly the obesity, hyperglycemia, hyperlipidaemia, insulin insensitivity and increased atherogenic index (AI). Treatment of SSC along with feed material decreased the weight gain, normalised the blood glucose (BG) level, reduced the serum cholesterol and improved the glucose tolerance significantly. In the oral glucose tolerance test (OGTT), rats fed with HFD supplemented with 2% and 4% SSC significantly reduced the plasma glucose after 120 min of glucose loading, indicating an improved glucose tolerance. In conclusion, the intake of SSC supplementation can be adopted as a therapeutic strategy for the prevention of obesity induced Type 2 hyperglycemia.     

Fumonisin production by Fusarium species isolated from cereals and feeds in Spain.

The ability of Fusarium species to produce fumonisins was studied with 145 isolates of the following species: F. moniliforme (119 isolates), F. subglutinans (12 isolates), F. proliferatum (9 isolates), F. avenaceum (1 isolate), F. oxysporum (1 isolate), and F. semitectum (3 isolates). All isolates were cultured on autoclaved corn kernels. The production of fumonisins was determined by a high-performance liquid chromatography-o-phthaldialdehyde-fluorescence method. Fumonisin production was restricted to isolates of F. moniliforme (94.1%) and F. proliferatum (100%), in the section Liseola, including all strains isolated from wheat, barley, peas, and soybean. One strain of F. proliferatum isolated from maize produced 30,949 microg/g of fumonisin B1 and 16,966 microg/g of fumonisin B2.     

Alkaline cooking (nixtamalisation) and the reduction in the in vivo toxicity of fumonisin-contaminated corn in a rat feeding bioassay

Nixtamalisation is a widely used food processing method in which whole kernel corn is cooked and steeped in alkaline water. It reduces the amount of fumonisin B1 (FB₁) that can be detected after cooking. However, the fate of FB₁ during nixtamalisation is not fully understood and potentially toxic reaction products, including matrix-associated “masked” FB₁ forms that are not detected by routine analytical methods might remain in nixtamalised corn. To assess how nixtamalisation of whole kernel corn affects fumonisin toxicity, male rats were fed diets containing low, mid or high levels of uncooked (LU, MU, HU) or alkaline cooked (LC, MC, HC) FB₁-contaminated corn for 3 weeks. The control diet contained uncontaminated corn only. Apoptotic kidney lesions of the type caused by FB₁ were not found in the LC or MC groups. Lesions in the group fed HC were minimal and less severe than those found in the rats fed LU, MU or HU. Furthermore, significantly increased sphinganine and sphingosine concentrations indicative of FB₁ exposure were found in the kidneys of the rats given LU, MU or HU. Concentrations were also elevated, but to a lesser extent, in rats fed HC, whereas sphinganine and sphingosine concentrations in rats given LC or MC did not differ from the control group. FB₁ concentrations in the LC (0.08?mg?kg^?1), MC (0.13?mg?kg^?1) and HC (0.37?mg?kg^?1) diets were markedly reduced compared with their LU (1.8?mg?kg^?1), MU (3.5?mg?kg^?1) and HU (4.2?mg?kg^?1) counterparts as determined by HPLC (n?= 1 analysis/diet). Taken together, the findings show that nixtamalisation is an effective cooking method for reducing the potential toxicity of FB₁ contaminated corn.