[Possibility of using microalgae Spirulina platensis powder in industrial production of Iranian traditional cookies]

There are a few studies about wheat flour fortification with powdered Spirulina platensis microalgae to produce industrial cookies. The objective of this study was to investigate the effects of Spirulina platensis microalgae used in production of traditional Iranian cookies on their nutritional value, color and texture. Samples of cookies were prepared using S. pirulina platensis at a level [% w/w] of 0.0, 0.5, 1.0 and 1.5%. The protein, iron and poluunsaturated fatty acid [PUFA] contents of the samples were measured by microkjeldahl, atomic absorption and GC mass chromatography, respectively; the peroxide value in the four samples was also determined. Sensory evaluation [hedonic scale 1-5] of the samples was made by 14 trained panelists. The iron, protein and gamma -linolenic acid contents of the fortified cookies were higher, and their peroxide value lower, than the respective control values. With regard to sensory evaluation, cookie samples containing 1.0% and 1.5% S. platensis scored highest following the control sample [p<0.05]. It is possible to produce cookies fortified with1.0-1.5% S. platensis with desirable nutritional and sensory characterstics

[Production of selenium-enriched yeast using a Plackett-Burman design]

Today dietary deficiency of selenium [Se], an important mineral in human nutrition, is common in many regions and communities. Se-enriched yeast, obtainable by growing Saccharomyces cerevisiae in Se-rich media, is considered as a source of organic Se suitable for alleviating its deficiency due to its high bioavailability, stability, digestability, and absorbability. Using a Plackett-Burman design, the effects of various culture medium conditions, including temperature [28 and 30°C], initial pH [4.5 and 5.8], shaking speed [130 and 160 rpm], fermentation duration [24 and 48 h], size of inoculum [30 and 60 g/l], Se concentration [15 and 25 micro g/ml] and time of Se addition [0 and 9 h], on the bioaccumulation of Se in the yeast were investigated.. The Se content in the yeast was determined by graphite-furnace atomic-absorption spectroscopy. The results showed that Se concentration, size of inoculums, temperature, time of Se addition and fermentation duration were, in ascending order, the most significant factors on the yield of total Se accumulation and organic Se formation in the yeast. Manipulating these conditions/variables could markedly affect the magnitudes of incorporation of Se and formation of organic Se in the yeast, the ranges being 107.9 to 287.6 mg/kg and 93.27 to 269.05 mg/kg, respectively. The most suitable culture medium conditions to attain the highest level of total and organic selenium Se biotransformation in yeast are a concentration of 25 micro g/ml sodium selenite, an inoculum size of 30 g/l, a temperature of 28°C, an initial pH of 5.8, a shaking speed of 130 rpm, an incubation time of 48 h, and adding the selenium source to the culture medium 9 hours after the start of fermentation

[Effect of incubation temperature and inoculation ratio of starter culture on propionic acid production in dairy beverage fermented with propionibacterium]

Increasing trends of overweight and obesity prevalence have prompted food producers to develop products that can enhance satiety signals. The role of short-chain fatty acids as satiety-inducing triggers seems to be of interest in this regard. The objective of this research was to investigate the impact of two process variables, namely, incubation temperature and inoculation ratio of starter bacteria, on propionic acid production in the fermented dairy beverages containing Propionibacterium immediately after fermentation and during cold storage. Fermented dairy beverage [FDB] samples were prepared using mixed cultures of Lactobacillus acidophilus and Propionibacterium freudenreichii ssp. shermanii at a ratio of 1:2, 1:4 and 1:8, repectively, at incubation temperatures of 30, 35 and 40°C, until the pH reached 4.0 +/- 0.1. Propionic, lactic and acetic acid contents of the samples were measured immediately after fermentation using HPLC. The FBD samples were refrigerated for 28 days and the concentrations of the acids in the samples with the highest propionic acid content were measured. Sensory evaluation of the samples produced was made by 11 trained panelists using the hedonic scale. The maximum propionic acid content [w/w%] was observed in a mixed culture of L. acidophilus and P. freudenreichii ssp. shermanii at a ratio of 1:4 and an incubation temperature of 30 °C. It increased from 0.75 at day 0 to 1.2 at day 28 during storage at 4°C. The incubation temperature had a statistically significant inverse effect [P<0.05] on the propionic acid production in the fermented dairy beverages

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

[Comparison of bench-scale production of xanthan by xanthomonas campestris in solid state and submerged fermentation]

Xanthan gum is an important natural biopolymer with numerous applications in various technologies, specially food industry. In this research, microbial production of xanthan by Xanthomonas campestris PTCC1473 from sugarcane molasses and date sugar in submerged fermentation [SmF] and also dried date waste [cake produced after pressing] in solid state fermentation [SSF] were compared. The Plackett-Burmann design [PBD] was used in this study. Chemical composition and characteristics [dried cell weight, nitrogen, moisture, ash and pH] of the substrates were determined. Yeast malt broth [YMB] and yeast malt agar [YMA] were used as maintenance and inoculum preparation media, and incubation was performed in a shaker incubator [at 28degreeC, 72 h and 200 rpm]. The fermentation medium was centrifuged at 5degreeC and 21055 multiplied by g for 50 minutes and the supernatant separated from the pellet for further xanthan extraction. After precipitation of xanthan by isopropanol, resuspension and further purification by centrifuge [at 2056 x g], the xanthan dry weight was determined. The effects of several variables, including the kind and concentration of carbon [date sugar and sugarcane molasses], nitrogen [ammonium nitrate and diammonium phosphate] and phosphorus [KH2PO4], temperature, shaking, and size and age of inoculum, on the yield were determined. The most effective variables were found to be the type of carbon and nitrogen sources in the medium. It can be concluded that both the yield [% w/w of xanthan/consumed sugar] and productivity [g/g.day xanthan/consumed sugar] are higher in SmF [22.4 and 7.46] than in SSF [13.3 and 4.43]. In addition, date extract results in a higher productivity than date waste and sugarcane molasses. The xanthan yield could be increased by changing the composition and physical conditions of the culture medium