Impact of different roasting conditions on sensory properties and health-related compounds of oat products.

Due to their high content of ß-glucan, the consumption of oat products can contribute to a healthy diet. Roasting may improve sensory properties but could also affect the nutritional value of oat products. Therefore, the aim of the present study was to analyse the impact of different roasting conditions (140-180 °C, approx. 20 min) on sensory quality, health-related compounds (e.g. acrylamide, ß-glucan) and viscosities of oat kernels and flakes. Roasting resulted in oat flakes with improved sensory properties. Acrylamide formation increased with higher roasting temperatures in kernels, thin and thick flakes. Contents of fat, protein, starch and ß-glucan were not affected by roasting, whereas dietary fibre fractions were marginally modulated. Viscosities were significantly reduced with increasing roasting temperatures. The results indicate that roasting up to 160 °C is a processing technique with potential to generate oat products with improved sensory quality and favourable nutritional composition.

Impact of different roasting conditions on chemical composition, sensory quality and physicochemical properties of waxy-barley products.

The consumption of ß-glucan-rich barley can contribute to a healthy diet. Sensory properties may be improved by roasting whereby the nutritional value should be preserved. The aim of the present study was to investigate the impact of different roasting conditions (160-200 °C, 20 minutes) on sensory quality, health-related compounds and viscosity in ß-glucan-rich barley kernels, thin and thick flakes. Sensory quality was improved by roasting. Acrylamide levels increased due to roasting to maximum values of 322 µg kg-1 (kernels), 586 µg kg-1 (thin flakes) and 804 µg kg-1 (thick flakes). No relevant impact of roasting on the contents of fat, protein, starch and ß-glucan was observed, whereas dietary fibre fractions were marginally modulated. Roasting significantly decreased viscosity 1.9-fold (kernels), 2.4-fold (thin flakes) and 2.7-fold (thick flakes), on average. In conclusion, improved sensory quality along with a favourable healthy composition of barley products may be achieved by roasting over a low to medium temperature range.

Pickering emulsifiers based on hydrophobically modified small granular starches Part II - Effects of modification on emulsifying capacity.

Small granular starches from rice, quinoa, and amaranth were modified with octenyl succinic anhydride (OSA) at 5 defined intervals (0-3.0%) and investigated with respect to emulsifying capacity and stability. Starch granule surfaces were characterized by Brunauer-Emmett-Teller and contact angle measurements. Emulsifying capacity was characterized by multiple light scattering (MLS) and particle size analysis. Stability towards environmental stress was characterized by centrifugation and MLS. Surface hydrophobicity and emulsifying capacity correlated with starch type and modification level. Quinoa stabilized emulsions had the smallest droplet size (e.g. 59.2 µm at 3.0% OSA) and superior stability, both before and after centrifugation, especially at the lowest modification levels. Rice and amaranth had larger droplets (99.8 and 84.1 µm at 3.0% OSA respectively). Amaranth, despite its small size showed poorer performance than quinoa, especially at lower modification levels. The higher emulsifying efficiency of quinoa starch granules attributed to the higher protein content.

Pickering emulsifiers based on hydrophobically modified small granular starches - Part I: Manufacturing and physico-chemical characterization.

Small granular starches from rice, quinoa and amaranth were hydrophobized by esterification with octenyl succinic anhydride (OSA) in an aqueous alkaline slurry to obtain series of modified starches at defined intervals (i.e. 0.6, 1.2, 1.8, 2.4, 3.0%). The physical and the physico-chemical properties of the starch particles were characterized by proximate analysis including protein level, amylose level and dry matter. The shape and size of the starch granules were characterized by scanning electron microscopy and light scattering. The gelatinization properties were characterized by differential scanning calorimetry. The degree of modification was determined by titration with NaOH. With regard to the emulsion formulation and in order to assess the emulsifying capacity of the small granular starches, the effect of starch type, degree of modification and starch concentration on the resulting emulsion droplet size were evaluated by light scattering and optical microscopy. Emulsifying properties were found to depend on the degree of substitution, size of the granules and the starch to oil ratio of the formulation. Quinoa starch granules, in general, had the best emulsifying capacity followed by amaranth and rice. However, in higher starch concentrations (>400mg/mL oil) and adequate levels of OSA (3.0%) amaranth performed best, having the smallest size of starches studied.

Acrylamide formation and antioxidant level in biscuits related to recipe and baking.

Heated plant foods may contain compounds with adverse health effects (e.g. acrylamide). On the other hand, health-promoting compounds (e.g. antioxidants) have also been identified in such foods. Therefore, a baking experiment with biscuits was carried out to study the potential impact of both acrylamide and antioxidants in that food. Two different wheat flour types - wholemeal (WMF) and white flour type 550 (T550; 0.55% mineral content) - as well as recipe (fat and leavening agent) and thermal input (temperature × time) were changed. Furthermore, the effect of an enzymatic asparagine hydrolysation was tested. Antioxidants were determined with two independent procedures ABTS - (2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate)) and FRAP-assay (ferric reducing ability of plasma). WMF samples resulted in an unchanged acrylamide level, but in a significantly higher antioxidant concentration when compared with T550 samples (149 and 141 µg kg(-1) acrylamide and 9.1 and 5.1 mmol TE kg(-1) FW ABTS for WMF and T550, respectively). A reduced fat content yielded in an increased volume. Raising agents had no effect on acrylamide levels, but antioxidants were higher in samples with sodium bicarbonate (SBC) than with ammonium bicarbonate (ABC). Thermal input (temperature × time; 150°C × 25 min to 240°C × 9 min) indicated an exponential acrylamide increase especially at higher temperatures (from 75 to 236 µg kg(-1)), whereas antioxidant increase was linear (from 7.0 to 7.7 mmol TE kg(-1) FW, ABTS). FRAP and ABTS values were correlated on a low level, whereas acrylamide content of biscuits was correlated with FRAP and lightness (R (2 )= 0.62 and 0.47, and 0.71 and 0.85 for WMF and T550, respectively). The enzyme asparaginase reduced acrylamide formation by about 50% for both raising agents (SBC and ABC, respectively), whereas antioxidant levels were not affected. An evaluation of recipe variants with low acrylamide and high antioxidants indicated the advantage of wholemeal biscuits.

Acrylamide in fried and roasted potato products: a review on progress in mitigation.

The workshop of the European Commission and the Confederation of the Food and Drink Industries of the European Union (CIAA) held in March 2006 in Brussels, Belgium, discussed the key knowledge and achievements in the mitigation of acrylamide. This paper presents the progress made by the potato sector and identifies areas for future research. Because of the important contribution of potato products to acrylamide intake, it is an area that has received much attention. The discovery of the method of formation and the role of reducing sugars meant that long-standing knowledge in respect of sugar and fry colour could be used to identify methods of mitigation. Improvement in parameters such as (1) potato variety, (2) potato storage temperature, (3) process control (thermal input, pre-processing), (4) final preparation, and (5) colour have all contributed to a significant overall reduction in the average acrylamide content in French fries and potato crisps (termed 'chips' in the USA). There is evidence that the limit of reduction that these measures can offer for crisps has now been approached, but clearly more can be done for French fries and roasted potato products. The use of asparaginase offers potentially significant reduction in certain prefabricated potato products. More research is required into new potato varieties and the agronomical factors that influence the levels of asparagine and sugars in potatoes.

Influence of dough ingredients on 3-chloropropane-1,2-diol (3-MCPD) formation in toast.

The influence of different dough ingredients such as fat, salt, sourdough, emulsifiers, and sugar on the formation of 3-chloropropane-1,2-diol (3-MCPD) during toast preparation under domestic conditions was investigated. In comparison with a fat-free recipe, addition of 1% peanut fat considerably increased 3-MCPD formation, but varying the fat (2-5%) or salt (1.6-2.4%) contents within technological acceptable limits did not show any significant differences. A baking agent, which is usually commercially applied by many toast bakers or industrial toast manufacturers, increased 3-MCPD formation in toasted bread slices. Considerable evidence was found that the baking agent's main component sucrose had the major part in increasing 3-MCPD levels. Emulsifiers containing monoacylglycerols moderately increased 3-MCPD levels, but the addition of lecithin did not have any significant influence. 3-MCPD levels showed a good correlation with the lightness (L* value) of the bread slices; their 3-MCPD content increased exponentially towards dark coloured toasts. The relation between 3-MCPD and 2-MCPD was an average of 3:1 in all samples. Dichloropropanols such as, for example, 1,3-dichloropropanol could not be detected.