The effect of cooking on acrylamide and its precursors in potato, wheat and rye

The relationship between acrylamide and its precursors, namely free asparagine and reducing sugars, was studied in simple cakes made from potato flake, wholemeal wheat and wholemeal rye, cooked at 180 degrees C, from 5 to 60 min. Between 5 and 20 min, large losses of asparagine, water and total reducing sugars were accompanied by large increases in acrylamide, which maximized in all three products between 25 and 30 min, followed by a slow linear reduction. Acrylamide formation did not occur to any extent until the moisture contents of the cakes fell below 5%. A comparison of each type of cake with a commercial product, made from the same food material, showed that acrylamide levels in all three commercial products were well below the maximum levels in the cooked cakes.

Effects of sulphur nutrition during potato cultivation on the formation of acrylamide and aroma compounds during cooking

Lack of sulphur nutrition during potato cultivation has been shown to have profound effects on tuber composition, affecting in particular the concentrations of free asparagine, other amino acids and sugars. This is important because free asparagine and sugars react at high temperatures to form acrylamide, a suspect carcinogen. Free amino acids and sugars also form a variety of other compounds associated with colour and flavour. In this study the volatile aroma compounds formed in potato flour heated at 180 °C for 20 min were compared for three varieties of potato grown, with and without sulphur fertiliser. Approximately 50 compounds were quantified in the headspace extracts of the heated flour, of which over 40 were affected by sulphur fertilisation and/or variety. Many of the 41 compounds found at higher concentrations in the sulphur-deficient flour were Strecker aldehydes and compounds formed from their condensation, whereas only one compound, benzaldehyde, behaved in the same way as did acrylamide and was found at higher concentrations in the sulphur-sufficient flour. The reasons for these effects are discussed.

Sensory and instrumental analyses of volatiles generated during the extrusion cooking of oat flours

Three batches of oats were extruded under four combinations of process temperature (150 or 180 °C) and process moisture (14.5 and 18%). Two of the extrudates were evaluated by a sensory panel, and three were analyzed by GC-MS. Maillard reaction products, such as pyrazines, pyrroles, furans, and sulfur-containing compounds, were found in the most severely processed extrudates (high-temperature, low-moisture). These extrudates were also described by the assessors as having toasted cereal attributes. Lipid degradation products, such as alkanals, 2-alkenals, and 2,4-alkadienals, were found at much higher levels in the extrudates of the oat flour that had been debranned. It contained lower protein and fiber levels than the others and showed increased lipase activity. Extrudates from these samples also had significantly lower levels of Maillard reaction products that correlated, in the sensory analysis, with terms such as stale oil and oatmeal. Linoleic acid was added to a fourth oat flour to simulate the result of increased lipase activity, and GC-MS analysis showed both an increase in lipid degradation products and a decrease in Maillard reaction products.

Volume-based size distribution of accumulation and coarse particles (PM0.1–10) from cooking fume during oil heating

Particulate matter generated during the cooking process has been identified as one of the major problems of indoor air quality and indoor environmental health. Reliable assessment of exposure to cooking-generated particles requires accurate information of emission characteristics especially the size distribution. This study characterizes the volume/mass-based size distribution of the fume particles at the oil-heating stage for the typical Chinese-style cooking in a laboratory kitchen. A laser-diffraction size analyzer is applied to measure the volume frequency of fume particles ranged from 0.1 to 10 μm, which contribute to most mass proportion in PM2.5 and PM10. Measurements show that particle emissions have little dependence on the types of vegetable oil used but have a close relationship with the heating temperature. It is found that volume frequency of fume particles in the range of 1.0–4.0 μm accounts for nearly 100% of PM0.1–10 with the mode diameter 2.7 μm, median diameter 2.6 μm, Sauter mean diameter 3.0 μm, DeBroukere mean diameter 3.2 μm, and distribution span 0.48. Such information on emission characteristics obtained in this study can be possibly used to improve the assessment of indoor air quality due to PM0.1–10 in the kitchen and residential flat.

Waste cooking oil as an energy resource: review of Chinese policies

Converting waste cooking oil into biofuel represents a three-win solution, dealing simultaneously with food security, pollution, and energy security. In this paper, we encode the policy documents of waste cooking oil refining biofuel in China based on content analysis, and explore the related policies from the two dimensions as basic policy tools and enterprises supply chain. Research indicates the weak institution coordination of policy issuing entities. Also, the findings show that tools of regulatory control and goal planning are overused. Policies of government procurement, outsourcing and biofuel consumption are relatively scarce. Generally, government focuses more on formulating policies from the strategic, administrative and regulatory aspects, while less on market-oriented initiatives as funding input and financial support.

December 2007: Cooking with the Federal Government

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Cutaneous myxosarcoma in a Syrian hamster (Mesocricetus auratus)

The pathological findings in a 2-years-old Syrian hamster (Mesocricetus auratus) with a cutaneous myxosarcoma are described. Grossly, there was a large cutaneous mass in the right cervical region. Microscopical evaluation revealed a myxosarcoma characterized by pleomorphic, fusiform cells loosely arranged, randomly distributed, and presenting a moderate amount of basophilic amorphous stroma. There were hemorrhagic areas within the tumor. The basophilic amorphous stroma was positive to Alcian blue confirming the presence of a mucopolysaccharide matrix. Immunohistochemically, the neoplastic cells expressed vimentin, and were negative for cytokeratin or glial fibrillary acidic protein (GFAP).

Paracoccidioides brasiliensis isolated from armadillos is virulent to Syrian hamsters

Isolates of Paracoccidioides brasiliensis may vary in virulence according to time of in vitro subcultivation. The present study compared the morphology and pathogenicity to hamsters of two P. brasiliensis isolates: one obtained from human lesions and maintained in the laboratory for several years (Pb-18) and the other isolate recovered from hamsters inoculated with organ homogenates from armadillos (Pb-T). The microscopic morphology of Pb-18 and Pb-T showed yeast cells with similar diameter. However, Pb-T produced a significantly higher number of buds per mother cell than Pb-18. Besides, the mycelial form of Pb-T developed abundant sporulation during 8 weeks of culture which was absent in the Pb-18 isolate. Virulence studies demonstrated that mortality rates, antibody levels, fungal load and extent of lesions in the organs were significantly higher in animals infected with Pb-T. The results demonstrated that Pb-T recently isolated from an animal was more virulent than Pb-18. These differences between the two P. brasillensis isolates may be indicators of virulence attenuation in this fungal species.

Experimental paracoccidioidomycosis of the Syrian hamster: fungicidal activity and production of inflammatory cytokines by macrophages

Phagocytic cells play an important role in nonspecific resistance to fungal infection by mediating an inflammatory response and by a direct fungicidal action. In this study, the functional activity of peritoneal macrophages obtained from hamsters experimentally infected with strain Pb18 of Paracoccidioides brasiliensis was evaluated during 16 weeks of infection. The results showed that macrophages had a higher spreading ability associated with increased production of tumor necrosis factor alpha (TNF-alpha) and enhanced fungicidal activity during the early periods of infection. TNF-alpha levels remained elevated during all periods studied, while low levels of interleukin-1 beta (IL-1 beta) were produced during the infection. A necrotic area with dead fungi was observed at the inoculation site and the infection disseminated only to liver and lymph nodes in a few animals. These results suggest that during the early stages of infection with P. brasiliensis, macrophage activation by the high levels of TNF-alpha limited fungal dissemination. In contrast, in the later stages of infection, high levels of TNF-alpha were observed while the fungicidal activity of macrophages was lower and the animals presented loss of vitality resulting in their death. These observations suggest a complex role of TNF-alpha in experimental paracoccidioidomycosis of Syrian hamsters, involving not only resistance but also pathogenesis.

Natural killer cell activity in experimental paracoccidioidomycosis of the Syrian hamster

Com o objetivo de avaliar a atividade de células natural killer na paracoccidioidomicose experimental do hamster, 80 hamsters foram infectados por via intratesticular com Paracoccidioides brasiliensis e sacrificados após 24h, 48h, 96h, 1, 2, 4, 8 e 11 semanas de infecção. Como controle foram avaliados 40 hamsters normais, não infectados. Os animais foram submetidos ao estudo da atividade citotóxica de células NK pela técnica de single-cell assay e da resposta imune humoral pelas técnicas de imunodifusão dupla e Elisa. A produção do fator inibidor da migração de macrófagos em presença de Phytohemaglutinina e antígeno de P. brasiliensis e a histopatologia das lesões foram estudadas após 1,4, 8e 11 semanas de infecção. Os animais infectados, quando comparados aos controles, apresentaram níveis de atividade NK significativamente elevados durante as 4 primeiras semanas de infecção, havendo diminuição dessa atividade a partir da 8ª semana. Foi observada correlação inversa entre atividade NK e níveis de anticorpos específicos e, associação entre diminuição da atividade NK, depressão de resposta imune celular e aumento da extensão das lesões histopatológicas. Os resultados sugerem que após ativação inicial, as células NK são incapazes de controlar a disseminação do fungo pelos tecidos. A depressão da atividade NK na fase tardia da infecção parece estar relacionada com os distúrbios imunorregulatórios associados à paracoccidioidomicose.

Dialysable leukocyte extracts modify the course of experimental paracoccidioidomycosis in the Syrian hamster

The effect of dialysable leukocyte extracts (DLE) obtained from hamsters immunized with Paracoccidioides brasiliensis (immune DLE) and from non-immunized hamsters (non-immune DLE) was studied in hamsters inoculated with P. brasiliensis by the intratesticular route. Treatment with immune or non-immune DLE was started during the third week of infection and was repeated at 7, 11, 15 and 19 weeks. A group of untreated infected animals was used as control. Animals were submitted to the delayed hypersensitivity skin test to P. brasiliensis antigen (PbAg) in vivo and assayed in vitro by the macrophage migration inhibition test in the presence of Phytohemagglutinin (PHA) and PbAg and by immunodiffusion for specific antibody. The animals were sacrificed at 4, 8, 12, 16 and 20 weeks. The morphology and extension of the lesions were studied at the inoculation site, and in lymph nodes, lungs, liver, spleen and kidneys. In contrast to the controls, animals treated with both DLEs maintained a positive cell-mediated immune response throughout the experiment and developed less extensive infection with a significantly lower number of fungi in the lesions. The results suggest that immune and non-immune DLE preparations modified the evolution of experimental paracoccidioidomycosis with equal efficiency. This similarity may be explained by the immunoregulatory activities of both extracts.

OPTIMIZATION OF EXTRUSION COOKING PROCESS FOR CHICKPEA (CICER-ARIETINUM, L) DEFATTED FLOUR BY RESPONSE-SURFACE METHODOLOGY

Response surface methodology was employed to optimize the production of a snack food from chickpea. The independent variables, process temperature (123-137-degrees-C) and feed moisture (13-27% d.s.b.) were selected at five levels (rotatable five level composite design: - square-root 2, -1, 0, 1, + square-root 2) in the extrusion of defatted chickpea flour. Response variables were expansion ratio, shear strength of the extrudate and sensory preference assessed by an untrained panel. Expansion ratio increased steadily with decrease in feed moisture similar to cereal extrusion. Regions of maxima were observed for sensory preference and shear strength, and these two product attributes were linearly related. The most acceptable chickpea snack was rated higher than a commercial corn snack.

THE CASSAVA (MANIHOT-ESCULENTA, C) CV PIONEIRA .3. COOKING CHARACTERISTICS

The edible parts of cassava cultivar Pioneira roots after 12 and 24 months of cultivation were analysed for human consum. The yield was 63% when the roots were harvested at the right time (12 months), and lower (58%) for older roots, with 24 months. Total cyanide contents were 62,0 - 61,8 and 58,0 - 63,4 ppm, respectively. Cooking time was 13,5 min and 19,5 min, respectively, although the cooked mass quality was similar good. The edible part of the roots was processed in french fries or tholes, submited to two treatment: blanching for three minutes and boiling for ten minutes. Treated and in natura tholes were fried in vegetable oil at 190-degrees-C. The effect of freezing (-20-degrees-C for 60 days) on the cooking quality was also evaluated. The frozen storage reduced the total cyanid content in all treatment. The rate of cyanid decrease were 45%, 84% and 88% with frying, blanching and frying, and boiling and frying, respectively. Blanching followed by frying assured a safe cyanid level for human consum as well as a good acceptance in sensorial analysis. The influence of the age of the roots in cooking quality was a decrease in softness. Frozen storage softened the 24 month old roots and worsened the flavor of 12 month old root. For table purposes cassava roots should be processed in french fries and blanching, what would allow frozen storage of edible part.