Mycoprotein production by Fusarium venenatum in surface culture using a central composite design

Due to their nutritional, physical and chemical characteristics, mycoproteins, produced in the process of fungal growth, have been proposed to be used as a food additive for man. In this study a central composite design was applied to assessing the effect of seed size and initial concentrations of carbon and nitrogen sources on mycoprotein production by Fusarium venenatum [ATCC20334] from date sugar. Chemical composition [percent dried cell weight, nitrogen, moisture, and ash] and pH of the substrate were determined. Vogel culture medium was used for maintenance and inoculum preparation, and incubation was done at 30 °C for 72h. Dried cell weight was measured by the oven method. The experimental results were fitted to a full quadratic second order polynomial equation and the optimization of response was done with Minitab 14 software. Optimum conditions were determined and a confirmation test was conducted. The regression coefficient of the model presented for mycoprotein production [based on dried cell weight] was 98.0%. The optimum conditions for the mycoprotein production included a seed size of 15.39% v/v, and a carbon and nitrogen source of 20 and 4.35 g/L, respectively. The predicted value for the optimum production of dried biomass was 5.032 g/L. The reconfirmation test was conducted at the optimum conditions and the result obtained was 4.84 g/L of biomass production. The regression coefficient indicates accuracy and suitability of the model for the experimental data. By changing the inoculum conditions and the chemical composition of the culture medium, optimal growth of Fusarium venenatum and, consequently, maximum biomass production, can be achieved. Use of date syrup as an available and domestic Iranian substrate for modification of Vogel medium makes possible protein production at an industrial scale in surface culture

[Effect of potato cultivar on acrylamide formation in potato chips]

In April 2002, a research group at Stockholm University and the Swedish Food Administration announced that significant amounts of acrylamide might be formed during common heat processing of foods. Since acrylamide is classified as "probably carcinogenic to humans" by the International Agency for Research on Cancer [IARC], these findings were considered as alarming. The most important food sources of dietary acrylamide are fried potato products like chips and French fries, which are popular snacks in Iran. The aim of this study was to investigate the effects of reducing sugars and amino acids in three 'potato cultivars on acrylamide formation in potato chips produced on a laboratory scale. Potato chips samples were produced on lab-scale from three potato cultivars namely Sante, Agria and Omidbakhsh by frying at 180°C for 4.15 min. Reducing sugars [glucose and fructose] and asparagine concentration in raw potato samples were determined using HPLC. A suitable and valid method was set up for determination of acrylamide in the chips samples by gas chromatography/mass spectrometry, GC/MS. The reducing sugars and acrylamide contents were significantly different among potato chips samples produced from different cultivars [p<0.05]. The highest amount of reducing sugars was found in cultivar Sante [3513 mg/kg] followed by Agria [2111 mg/kg] and Omidbakhsh [1622 mg/kg], respectively. On the other hand, cultivar Omidbakhsh had the highest amount of asparagine [1871 mg/kg]. The highest amount of acrylamide [8825 mg/kg] was formed in the chips from cultivar Sante and the lowest amount was formed in the chips from cultivar Omidbakhsh [5112 micro g/kg]. A high content of asparagine in raw potatos was not necessarily an indication of high content of acrylamide in the produced chips. The two cultivars with higher content of reducing sugars, showed the higher potential for acry1amide formation in the chips. This indicates that the concentration of reducing sugars is a more important parameter than asparagine content in the formation of acrylamide in potato chips. The selection of proper potato cultivars with naturally lower contents of precursors of acrylamide specially reducing sugars is important factor to reduce the acrylamide formation during production of potato chips. With respect to the results obtained from this study, it is suggested that cultivar Omidbakhsh is the most suitable cultivar in Iran for the industrial production of potato chips with low levels of acrylamide