Josiane Roberto Domingues

Foam mat drying of Tommy Atkins mango: Effects of air temperature and concentrations of soy lecithin and carboxymethylcellulose on phenolic composition, mangiferin, and antioxidant capacity

In this study, foam mat drying was applied to Tommy Atkins mango. Using a multifactorial design, the effect of soy lecithin (L) and carboxymethylcellulose (CMC) used as foam stabilizers (0-1.50g/100g), as well as temperature (T) (53-87°C), on phenolic content and antioxidant capacity of mango were evaluated. Mango pulp contains antioxidant, such as mangiferin, that can be utilized in foods to enhance their functional properties. Our results indicated that L and T had negative effects (p<0.05) on the phenolic content and antioxidant capacity, whereas CMC had a positive effect (p<0.05). Increasing the total amount of phenolic compounds present in dried mango contributed to the higher antioxidant capacity after the drying process. This study concluded that a drying T of 80°C, and a concentration of 0.30g/100g of CMC and L are optimal for increased retention of phenolic compounds and antioxidant capacity.

Survival of Shiga toxin-producing Escherichia coli O157:H7 in Minas frescal cheese

Shiga toxin-producing Escherichia coli (STEC) O157:H7 strains (isolated by cattle’s faeces and a reference strain, EDL933), were inoculated into pasteurized milk (102 and 103 cells.mL–1) to prepare the Minas frescal cheese. As control was used uninfected milk. Physicochemical and microbiological analyses were performed to milk and elaborated cheese. The O157:H7 strains were quantified in the stages of cheese processing and during 0, 2, 4, 5, 7, 10 and 15 storage days at 8 °C onto Sorbitol MacConkey Agar supplemented with potassium tellurite and cefixime (CT-SMAC). O157:H7 was not present in the pasteurised milk prior to the artificial inoculation. At the end of the processing the cheese had 10 to 100 times more STEC O157:H7 than the initial inoculum. During the storage, the Minas frescal cheese exhibited the largest population increase on the 4th and 5th day when inoculated with 102 and 103 cells.mL–1, respectively. Additionally, viable cells were found up to the 10th and 15th day, according to the amount of initial inoculum. This number of cells is able to cause infection in humans, and therefore, Minas frescal cheese, even when stored under refrigeration, is a potential vehicle of disease caused by STEC O157:H7.

Biomass production by Arthrospira platensis under different culture conditions

In biotechnological processes, the culture media components are responsible for high costs and exert a strong influence on the cyanobacteria behavior. The objective of this study was to evaluate the Arthrospira platensis growth potential for biomass production under different cultivation conditions using an experimental design. Three factors that are important for cyanobacteria growth were evaluated: sodium bicarbonate (9 to 18 g/l), sodium nitrate (1.25 to 2.5 g/l), and irradiance (20 to 120 µmol photons/ m 2 .s -1 ). The results showed that the concentration of NaN D 3 in the A. platensis medium can be reduced, resulting in increased concentrations of biomass produced. There was a higher biomass production due to the increase in the concentration of NaHC D 3 and irradiance, mainly when these two factors varied tending towards the highest values studied. The results demonstrate the potential to produce Arthrospira platensis with lower costs and effluent generation without affecting cultivation performance.

Effect of calcium addition and pH on yield and texture of Minas cured cheese

Milk calcium concentration is a factor related to cheese texture, an important rheological property of cheese quality as perceived by consumers. This study aimed to evaluate the effect of different pH conditions (5.8 and 6.6) and calcium addition (0, 150, 300 ppm of CaCl2), on yield and nutrient retention of the clots obtained and on the texture of Minascured cheese. Clots were analyzed for wet and dry yield, percentage content and retention of protein, fat and calcium. The texture of the cheese was evaluated by instrumental and sensorial tests. No differences were observed on the wet and dry yields, or on the protein content, fat and calcium retention of clots produced in the different experimental conditions. The instrumental evaluation showed that calcium addition significantly influenced the texture of cheeses, regardless of the pH of milk clotting. The sensory panel did not find a difference in the hardness ofcheeses produced at the same pH of milk clotting in function of CaCl2 addition. There was no difference in the texture of Minascured cheese due to the calcium addition to milk for dairy product consumers, which brings a new perspective on manufacture for cheese markers.

Inclusion complexes of yellow bell pepper pigments with β‐cyclodextrin: preparation, characterisation and application as food natural colorant

BACKGROUND This work aimed to prepare inclusion complexes using yellow bell pepper pigments and β-cyclodextrin by two different procedures (method A, ultrasonic homogenisation; method B, kneading), to characterise them and evaluate their colour stability in an isotonic beverage model. The extract/β-cyclodextrin ratio was 1:2 for both inclusion methodologies evaluated. The formed extract-β-cyclodextrin complexes and a physical mixture of extract and β-cyclodextrin were evaluated by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). RESULTS Both methodologies resulted in good complex yield and inclusion efficiency. The colour indices L* (lightness), a* (green/red) and b* (blue/yellow) of isotonic drinks added with the complexes were measured during storage under irradiance (1400 lx) and in the absence of light at temperatures between 25 and 31 °C for 21 days. CONCLUSION The complex obtained by inclusion method B promoted better colour protection for the beverage compared with the use of the crude extract, showing that the molecular inclusion of yellow bell pepper carotenoids can provide good results for that purpose.