The Use of Iron-Enriched Yeast for the Production of Flatbread

The most common cause of iron deficiency is an improperly balanced diet, in which the body’s need for iron cannot be met by absorption of this element from food. Targeted iron supplementation and food fortification may be the main treatments for iron deficiency in the population. However, many iron-rich supplements and foods have low bioavailability of this element. In our study, we used yeast enriched with iron ions to produce flatbread. The yeast cells accumulated iron ions from the medium supplemented with Fe(NO3)3·9H2O, additionally one of the cultures was treated with pulsed electric field in order to increase the accumulation. The potential bioavailability of iron from flatbread containing 385.8 ± 4.12 mg of iron in 100 g dry mass was 10.83 ± 0.94%. All the flatbreads had a moderate glycemic index. There were no significant differences in antioxidant activity against DPPH• between flatbread with iron-enriched and non-iron-enriched yeast. Sensory evaluation showed that this product is acceptable to consumers since no metallic aftertaste was detected. Iron enriched flatbread can potentially be an alternative to dietary supplements in iron deficiency states

Unconventional methods of extractions : green extraction

Extraction is a method of extracting a chemical from a solution or mixture of solid substances. Conventional methods of extraction, for example, Soxhlet method, require the use of hazardous solvents, are time-consuming and cause degradation of the extracted compounds. Green extraction is characterized by the speed, it gives a quantitative recovery of the extract and does not cause degradation of the components. It takes place at a lower energy consumption than conventional extraction. A number of novel alternatives to conventional extraction techniques have been proposed, including ultrasonic assisted extraction (UAE), supercritical fluid extraction (SFE), enzyme extraction or pulsed electric field. These techniques allow to reduce or eliminate the use of toxic solvents, improve process efficiency and extract quality. The temperature of the above-mentioned processes is low, which affects the behavior of temperature-sensitive substances. The widely used "green extraction" is SFE - extraction with supercritical fluid. The solvent is a supercritical fluid, most often carbon dioxide. Ultrasonic extraction is environmentally friendly, easy to use, versatile and relatively cheap compared to other innovative techniques. This technique can be used to extract, for example, polysaccharides, essential oils, proteins, peptides, dyes, pigments and bioactive substances. Extraction with the use of pulsed electric field is used to extract mainly polyphenols and other bioactive components. Extraction with enzymes (mainly pectinases, cellulases and hemicellulases) is widely used in the food industry, eg for clarifying beer and juices. The extraction yield depends on the solvent system, temperature, enzyme function, substrate availability and pH

Nutritional, Physiochemical, and Biological Value of Muffins Enriched with Edible Insects Flour

Edible insects are gaining attention as a novel food; however, studies with their use in food are still limited. This study aimed to determine the chemical composition, physical parameters, sensory acceptance, and biological properties of muffins enriched with different levels of cricket (Gryllodes sigillatus) and mealworm (Tenebrio molitor) flours. The approximate composition was analyzed, along with the physical and textural properties, color, and consumer acceptance. Moreover, the antioxidant properties, starch digestibility, and glycemic index were determined in vitro. As we expected, the protein content in muffins supplemented with insect flour increased, while the carbohydrates content decreased. Moreover, the total phenolic content and antioxidant capacity against ABTS·+ and DPPH· increased correspondingly as the percentage of insect flour in the muffins increased. The estimated glycemic index was lower for the fortified muffins than the control (p < 0.05). Additionally, enriched muffins were accepted by consumers, and their taste positively surprised respondents (p < 0.05). Therefore, the results obtained are satisfactory as regards the use of insects for the supplementation of traditional products, and further research into the addition of insects to other nutrient matrices is needed. Furthermore, examining the effect of insect addition on in vivo food biological activity is highly desirable

Accumulation of Vitamin C in Yeast under Pulsed Electric Field (PEF) Conditions

Enriching food with vitamin C is a process that challenges food engineers. To prevent the degradation of this vitamin, a microencapsulation can be used in Saccharomyces cerevisiae cells. Previous works have shown that applying a pulsed electric field can increase the efficiency of the accumulation of minerals in yeast. The aim of this study was to optimize PEF parameters in order to increase the accumulation of vitamin C in yeast cells, to evaluate the effect of electroporation on biomass and yeast viability, and to assess the effect of storage conditions on the vitamin C content and its antioxidant activity. The most effective accumulation of vitamin C in cells (approx. 1.3 mg/g dry mass) was achieved when a 20-h yeast culture was treated with PEF at a concentration of 5 mg/mL vitamin C in the medium. The optimal PEF parameters were: voltage of 1000 V, pulse width of 10 µs, treatment time of 20 min, and number of pulses, 1200. The process conditions did not affect significantly biomass production nor cell viability. Yeast cells with vitamin C were stored for 7, 14, and 28 days at 20 °C (after prior freeze-drying), 4 °C, and −22 °C. The lowest decrease in vitamin C content was observed for the freeze-dried yeast stored at 20 °C

Pulsed electric field (PEF) enhances iron uptake by the yeast Saccharomyces cerevisiae

The aim of the study was to investigate the influence of a pulsed electric field (PEF) on the level of iron ion accumulation in Saccharomyces cerevisiae cells and to select PEF conditions optimal for the highest uptake of this element. Iron ions were accumulated most efficiently when their source was iron (III) nitrate. When the following conditions of PEF treatment were used: voltage 1500 V, pulse width 10 µs, treatment time 20 min, and a number of pulses 1200, accumulation of iron ions in the cells from a 20 h-culture reached a maximum value of 48.01 mg/g dry mass. Application of the optimal PEF conditions thus increased iron accumulation in cells by 157% as compared to the sample enriched with iron without PEF. The second derivative of the FTIR spectra of iron-loaded and -unloaded yeast cells allowed us to determine the functional groups which may be involved in metal ion binding. The exposure of cells to PEF treatment only slightly influenced the biomass and cell viability. However, iron-enriched yeast (both with or without PEF) showed lower fermentative activity than a control sample. Thus obtained yeast biomass containing a high amount of incorporated iron may serve as an alternative to pharmacological supplementation in the state of iron deficiency

Determination of the content of Pb, Cd, Cu, Zn in dairy products from various regions of Poland

The toxicity of heavy metals and their capacity for accumulation in the human organism make it necessary to conduct monitoring of their concentration in food. The objective of the study was to determine the content of lead, cadmium, copper and zinc in milk and dairy products from various regions of Poland: the Lublin Region, Podlasie, Podkarpacie, and Silesia. The study showed the presence of the analysed heavy metals in most of the products. The content of lead was related to the level of industrialisation of a region. Higher levels of Pb were found in products from Silesia than in those from the other regions. The study revealed the presence of cadmium in 50% of the samples. Its content varied in range from 0.0067 to 0.0058 mg/kg. The levels of Cu and Zn concentration in the analysed products were within broad ranges, from 0.0015 to 4.94 mg/kg and from 0.01 to 56.44 mg/kg, respectively. In the case of all analysed elements an increase in their concentration was noted in cheese spreads and cottage cheeses. No relationship was found between the content of heavy metals in the analysed products, and the region of their origin

Effects of Ultrasound Technique on the Composition of Different Essential Oils

The objective of the experiment was to investigate the stability of the composition of selected essential oils in the model systems containing methanol and hexane solutions which were treated with ultrasound. Solutions of the oils, with a concentration of 90 mg/ml, were subjected to the effect of ultrasounds with a frequency of 20 kHz and an output power of 200 W for periods of 2 min and 10 min at 50% and 80% power. The experiment has shown no significant effect on the composition of the essential oils resulting from the applied parameters of the process in the tested model systems. The study indicates that the sonication parameters adopted in the experiment can be applied in the case of analogous systems containing essential oils in their composition

The effect of selected substances on the stability of standard solutions in voltammetric analysis of ascorbic acid in fruit juices

The objective of the study was to identify suitable additives stabilizing standard solutions of ascorbic acid (AA) that would not cause interference in the analytical process with the use of voltammetry in the determination of the AA content in food products. In addition, the effect of various conditions of storage of selected fruit juices and drinks on the concentration of vitamin C was studied. The study demonstrated that AA degradation was inhibited the most effectively by tartaric acid and its optimum concentration was set to 200 mg L-1. Analysis of selected fruit juices stored in various temperature conditions confirmed that an elevation of temperature and extension of the time of storage caused a decrease in the content of vitamin C in the analyzed samples, while closing the packages caused a limitation of the changes in concentration of this vitamin. On the basis of literature data and of the results obtained in the present study it can be concluded that fruit juices should be stored at a temperature lower than room temperature to retain their nutritive value

The Use of Ultrasound in Shaping the Properties of Ice Cream with Oleogel Based on Oil Extracted from Tomato Seeds

In this study, the possibility of using ultrasound technology as an alternative to traditional pasteurization and homogenization in ice cream production was presented. Three types of ice cream with different proportions of oleogel (5, 6, and 7%) prepared using tomato seed oil were studied. The fatty acid contents of the oil were analyzed. Using chemical analysis, dry matter, fat, protein, dietary fiber, ash, and pH of the ice cream samples were determined. The physical analysis included analysis of the ice cream samples using a differential scanning calorimeter (DSC) and determination of their first drop time, complete melting time, overrun, viscosity, hardness, and adhesiveness. The structure of the samples was evaluated using scanning electron microscopy. Fourier transform infrared spectroscopy spectra were measured using a dedicated QATR-S Single-Reflection ATR ACCESSORY with a diamond prism. With the increase in the proportion of oleogels, the fat and carbohydrate contents, the amount of freezable water, and the overrun of the samples were increased, whereas their viscosity and hardness were decreased. Oleogels were found to be a promising alternative to fat in ice cream rich in unsaturated fatty acids, and the ice cream samples prepared using ultrasound pasteurization showed lower overrun and viscosity and higher hardness