Selection and identification of xylose-fermenting yeast strains for ethanol production from lignocellulosic biomass

Ethanol production from lignocellulosic biomass is of economic interest due to the pressure to reduce fossil fuels consumption and land use for non-edible crops. Xylose is one of the main sugars obtained by hydrolysis of hemicellulose fraction of biomass, but industrial yeasts cannot ferment it. This work aimed to select, characterize and identify xylose-fermenting yeasts from Brazilian microorganisms collections with potential use in ethanol production. Xylose assimilation was tested by replica plating, and fermentation was tested with Durham tubes. Xylose-fermenting strains had their fermentative capacity quantified and compared to a reference strain (Scheffersomyces stipitis UFMG-IMH 43.2) and were identified by molecular techniques. Three strains isolated from plant exudates were able to ferment xylose and showed fermentative parameters similar to the reference strain. Two strains were identified as Candida parapsilosis and one was identified as Meyerozyma guilliermondii. The findings show the potential biotechnological use of these microorganisms.

Drum drying of unpeeled green banana pulp (Musa cavendishii) for bake stable fruit filling production.

There is a growing interest in food matrixes for the use of flour from unpeeled green banana in order to reduce waste in the production chain. Considering this, the present paper aims to studying the application of unpeeled green banana flour in the cold process performed to obtain bake stable fruit filling. The unpeeled green banana pulp (Musa Cavendishii) was dried using a single rotating drum, thus obtaining the flour. The dried flour was then analyzed for its chemical composition, amylose and resistant starch content, water absorption capacity and pasting properties. The drying reduced the amount of resistant starch and produced pregelatinized starch. The obtained flour showed physical and nutritional characteristics which enabled the development of the filling formula by using a central composite design combining levels -1 and +1, two axial points (± α), two central points, and chemical composition, water activity, Brix, and texture as response variables. The amount defined by central-composite design of unpeeled green banana flour, modified starches and other ingredients resulted in an elastic, viscous, bake stable fruit filling.

Diversity of Staphylococcus coagulase- positive and negative strains of coalho cheese and detection of enterotoxin encoding genes

Three hundred samples of coalho cheese, from 15 different brands, of which seven were handmade made and eight industrialized, were evaluated in relation to the contamination profile by Staphylococcus coagulase-positive and negative and the occurrence of staphylococcal enterotoxin encoding genes. Two hundred and eight isolates of Staphylococcus sp. were subjected to phenotypic identification and 95 were subjected to genotypic identification through femA gene research and detection of genes (sea, seb, sec, sed, see, seg, seh, sei and sej) encoding enterotoxins, using the polymerase chain reaction technique (PCR). A total of 14 species of Staphylococcus were identified, of which three were coagulase-positive and eleven negative, especially: S. aureus, S. xylosus, S. cohnni spp. cohnii, S. saprophyticus, S. epidermidis, S. hyicus, S. lentus, S. sciuri, S. cohnii spp. urealyticus, S. haemolyticus, S. chromogenes, S. lugdunensis, S. hominis e S. intermedius. In all the samples of handmade coalho cheese handmade there was a prevalence of S. aureus; while in the industrial samples S. xylosus (87.5%) and S. cohnii spp cohnii (50%) were predominant. The presence of the femA gene was detected in 95% (38/40) isolates of positive Staphylococcus coagulase and 16.4% (9/55) of coagulase-negative isolates. Among the enterotoxin encoding genes evaluated, there was prevalence of the seh gene (53.2%) in coagulase-positive strains and of the sec gene (46.8%) in coagulase-negative strains. The results suggest a re-evaluation of the Brazilian microbiological standards in relation to the genus Staphylococcus in foods.

MARKET AND SUSTAINABILITY OF FOOD PACKAGING: A REVIEW

Food packaging is an essential tool in the food industry for protecting products from environmental interference that may be detrimental to the product and to the consumers’ health. As a result, the global packaging market is growing and stimulates the development of new technologies to meet the industrial demand. However, with the growth of the production and use of materials from fossil sources, as well as the lack of adequate programs for post-consumer waste management, there has been a deliberate disposal of these materials into the environment, resulting in ecological impacts and health consequences. In this sense, renewable sources have gained prominence and biologically originated materials are one of the main alternatives for new applications in packaging.

BIOLOGICAL ACTIVITY OF ESSENTIAL OIL OF PITANGA (Eugenia uniflora L.) LEAVES

Natural extracts present antioxidant activity and can replace synthetic antioxidants. This study aimed to extract essential oil from Pitanga (Eugenia uniflora L.) leaves and evaluate its chemical composition, as well as antioxidant and antibacterial activities. The essential oil was obtained by hydrodistillation for 3 hours with a yield of 1.34 ± 0.18 %. The total antioxidant activity was evaluated by the DPPH and phosphomolybdenum methods. The oil presented an IC50 value of 100.96 µL mL‑1 and 1503.44 ± 29.48 mg α‑tocopherol mL-1 of oil. The major compounds identified by the GC-MS were germacrone (13.57%), spathulenol (7.49%), curzerene (5.31%) and α-cadinol (4.70%). The oil was also evaluated for its antimicrobial activity and was effective against Staphylococcus aureus. These results show that essential oil of pitanga leaves have good antioxidant and antimicrobial activity, being an alternative source of bioactive compounds.