Scielo RSS <![CDATA[Food Science and Technology]]> vol. 37 num. SPE lang. es <![CDATA[SciELO Logo]]> <![CDATA[Microencapsulation by lyophilization of carotenoids produced by <em>Phaffia rhodozyma</em> with soy protein as the encapsulating agent]]> Abstract Carotenoids are pigments that can be applied to food but they are unstable towards certain food intrinsic conditions, as well as processing ones. Microencapsulation is an alternative to increasing their stability. This study aimed to produce carotenoids by Phaffia rhodozyma crops and promote their microencapsulation by lyophilization with soy protein as the wall material, in different proportions. High process yield of 96% and encapsulation efficiency of around 65% were observed at the ratios under study. Well-defined and separate micrometer-scale particles with different shapes and sizes were formed and the protection of the compounds of interest was confirmed by differential scanning calorimetry which showed that the endothermic event – typical of the free extract after encapsulation – did not occur. <![CDATA[Oxidative stability of soybean oil added to coffee husk extract (<em>Coffea arabica</em> L.) under accelerated storage conditions]]> Abstract Several plants have been studied as potential sources of natural antioxidants for use in the food industry, especially polyphenols. The aim of this study was to evaluate the effects of hydroalcoholic extract from coffee husk on the oxidative stability of soybean oil when stored in an oven. Samples were maintained at a temperature of 60 °C and their oxidative stability was evaluated once every 5 days for a period of 20 days through the Rancimat equipament and analysis of peroxide value, conjugated dienes and tocopherols retention. The oxidation rate in terms of mass gain was evaluated once every 24 hours for a period of 24 days. Although the antioxidant TBHQ showed a better efficiency in the inhibition of oxidation, coffee husk extract showed a synergistic effect when used with the synthetic, delaying the appearance of degradation products. In addition, the freeze-dried extract showed the ability to reduce the mass-gain rate when used alone as well as when used in combination with the synthetic antioxidant butyl hydroxyanisole (BHA), noting a synergistic effect on oxidative stability between the extract and the BHA. Therefore, coffee husk extract could be considered a source of natural antioxidants for synthetic antioxidants substitution. <![CDATA[Incidence of aflatoxin M<sub>1</sub> in fresh milk from small farms]]> Abstract The objective of this work was to determine aflatoxin M1 in fresh milk from fifty-two small farms in the city of Concórdia - SC, Brazil. Samples from the cooling tanks of each property were collected from November 2014 to January 2015. The QuEChERS method was used for the extraction of aflatoxin M1, and quantification was performed in UHPLC-FL. 40.4% of the analyzed samples (eg, 21 samples) showed contamination levels by aflatoxin M1 above the maximum limit allowed by the Brazilian regulation, which is 0.5 μg L-1. These results suggest the importance of implementing Good Practices in obtaining feed for dairy cows, since the contamination of milk by aflatoxin M1 occurs through the biotransformation of aflatoxin B1, after the ingestion of feed or silage contaminated by the animals, posing risk to the animals themselves, as well as to consumers of milk and dairy products. <![CDATA[Effect of <em>Spirulina</em> addition on the physicochemical and structural properties of extruded snacks]]> Abstract Nowadays the demand for practical food like snacks increases worldwide, however the nutritional value in most these formulations is reduced. Due to its chemical composition with high protein concentration, the microalga Spirulina has been used on the production of enriched foods. The present study aimed to evaluate the effects of Spirulina sp. LEB 18 addition on snacks formulations and extrusion conditions on the physicochemical and structural properties of snacks. Protein concentration and physical properties such as expansion index, bulk density, hardness, water absorption index, water solubility index and color were determined. The results showed that the addition of Spirulina sp. LEB 18, temperature in the last zone of the extruder and feed moisture influenced the product responses. The increase in feed moisture increased the hardness, bulk density and water absorption index of the snacks. Higher concentrations of microalga produced snacks with higher protein content, total color difference (ΔE) and compact structure. The addition of 2.6% Spirulina produced snacks with up to 11.3% protein and with adequate physical and structural properties for consumption. Thus, snacks containing Spirulina are an alternative to the demand for healthy food of practical consumption. <![CDATA[Effect of <em>Bacillus spp</em>. on <em>Aspergillus westerdijkiae</em> growth, sporulation and ochratoxin A production in green-coffee medium]]> Abstract Aspergillus westerdijkiae is one of the most important spoilage and toxigenic fungi contaminating coffee beans and may produce ochratoxin A (OTA), a mycotoxin that characterize a health risk to the coffee consumers. Biological control strategies can be used for prevention of fungal invasion and decrease mycotoxin exposure. The aims of this study were to evaluate the in vitro effect of three Bacillus sp. biocontrol candidates on A. westerdijkiae mycelial growth, spore counts and OTA production. A green-coffee based medium was inoculated with A. westerdijkiae and Bacillus spp. (B. safensis RF69, B. amyloliquefaciens RP103 and B. subtilis RP242) and after incubation, the fungal growth, sporulation and mycotoxin production was evaluated. Mycelial growth rate was reduced in a range between 76-95% and conidial production was also significantly decreased. All isolates were capable of reducing OTA production in a range between 62-96%. The results showed that the biocontrol candidates may be an effective control method for A. westerdijkiae and OTA in coffee. <![CDATA[Effect of temperature and nitrogen concentration on biomass composition of <em>Heterochlorella luteoviridis</em>]]> Abstract The interest in microalga as a food supplement has grown due their high contents of carotenoids, polyunsaturated fatty acids and proteins. This study evaluated the effect of different temperatures (22, 27 or 32 °C) and sodium nitrate concentrations (12, 24, 36, 48 or 60 mg L-1 of N-NO3) in culture medium on Heterochlorella luteoviridis biomass production and composition. The highest biomass concentration (3.35 g L-1) was observed at the highest N-NO3 concentration. The N-NO3 concentration positively affected protein, carbohydrate and carotenoids contents of biomass. On the other hand, cells cultured at the lowest N-NO3 concentration showed a slight increment in lipid content. The major carotenoid was lutein (30.7 ± 1.4% of total carotenoids), and the polyunsaturated fatty acids were 37 ± 2% of total fatty acids. Low temperature improved the biosynthesis of ω3 type fatty acids by lowering the ω6:ω3 ratio. Overall, our results indicate H. luteoviridis can yield high biomass concentration under autotrophic growth, resulting in a biomass rich in carotenoids, mainly lutein, and ω3 polyunsaturated fatty acids. <![CDATA[Results from portable and of low cost equipment developed for detection of milk adulterations]]> Abstract This work presents the results of a device, MilkTech, developed to detect milk tampering, based on electrical measurements. The device indicates possible frauds by water, sodium chloride, caustic soda, ethyl alcohol and sodium bicarbonate. The advantages in relation to traditional methods are portability, low cost and detection of mixed frauds. The experiments were conducted in dairy plants at Governador Valadares, in Brazil. The results were compared with cryoscopy and chloride tests. It is demonstrated there is high correlation between MilkTech and Cryoscopy. For instance, the detection limit of the equipment for water addition with the set of analyzed data was 0.78% with precision of 1.1%. Adulterations with sodium chloride, caustic soda, ethyl alcohol and sodium bicarbonate are detected qualitatively, even when added with water, and MilkTech indicates “SUSPECT” milk.