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Given possible temperature variations in the cold chain during retail display of chilled food, this work evaluated the growth of Salmonella choleraesuis and Staphylococcus aureus inoculated in chicken breast fillet submitted to different temperature abuses. The bacterial growth was evaluated in Luria–Bertani broth and previously inoculated chicken breast fillet cooled for 12h and incubated at different temperatures (5, 20, and 25 °C) for 12 h and 5 ºC for 12 days. The maximum growth rate and maximum growth were determined. The microorganisms grew at all studied temperatures, with a significantly lower growth at 5 °C compared with 20 and 25 °C. S. choleraesuis showed higher growth than S. aureus in both culture medium and chicken breast, and major maximum growth in culture medium than chicken breast, at all studied temperatures. Salmonella sp. and S. aureus were not detected in the control treatment maintained at 5 °C, and the thermotolerant bacteria remained within the standards allowed by Brazilian legislation when stored for 12 days. However, temperature abuse resulted in the vulnerability and spoilage of chicken breast fillet quality. The effects of temperature abuse caused by negligence on the microbial growth (Ymax) and growth rate (µmax) in chicken breast fillet, under industrial conditions was demonstrated.

The aim of this work was to evaluate the production of carotenoids from red yeast Phaffia rhodozyma in a bioreactor using agro-industrial wastes. This study used a sequential strategy of e...

SUMMARY The aim of this study is to elaborate and evaluate structural characteristics of soybean gelato by varying the content of soybean protein concentrate (2.95 to 17.05%) and vegetable fat (7.95 to 22.05%) using experimental design. The replacement of milk by hydrosoluble extract and soybean protein concentrate presented itself as an alternative to gelato production with unique characteristics, especially in terms of protein, solubility, viscosity, melting point, overrun and acceptability. The addition of up to 5% (m/V) protein concentrate, 14% (by volume) soybean hydrosoluble extract, and 15% (by mass) vegetable fat to gelato formulations resulted in better structural characteristics, with viscosity ranging from 0.45–0.70 Pa∙s at 10 °C, a non-Newtonian behaviour and protein stability (total protein content 8.44% and solubility 41%). Soybean gelato structural analysis using X-ray diffraction revealed 15° and 35° diffraction angles at 2Θ, characterizing the crystalline part of the product. The thermal analyses showed four bands of mass loss in the temperature range of 40–600 °C, characterizing loss of moisture, decomposition of the soy protein and the fat/emulsifier of the formulations. Thus, the soybean gelato is an innovative product, lactose and milk protein-free with outstanding characteristics for the general public, mainly, for the populations with intolerance to such components.

This work has studied the semi-continuous carotenoids production by Sporidiobolus salmonicolor (CBS 2636) comparing the use of complex substrates and agroindustrial residues. The maximum total carotenoids concentration was 4376 μg L−1 in a 264 h period with complex substrates (80 g L−1 glycerol, 5 g L−1 malt extract, and 15 g L−1 peptone) and 7388 μg L−1 in a 288 h period with agroindustrial residues (80 g L−1 crude glycerol, 80 g L−1 corn maceration water, and 20 g L−1 rice parboiling water), showing an of approximate 54% increase, under the following conditions: 25 °C, pHinitial of 4.0, 180 rpm agitation rate, 1.5 vvm aeration rate, with 50% working volume cut. The maximum productivity on total carotenoids was 34.8 and 41.4 g L−1 h−1, the maximum productivity on cells was 0.058 and 0.104 g L−1 h−1, with specific maximum growth speeds of 0.05 and 0.08 h−1, obtaining the major carotenoid all-trans-β-carotene (83% and 81%), respectively.

This work aimed to produce ethyl esters from Chlorella vulgaris microalgae biomass, using an immobilized enzymatic catalyst associated with pressurized fluid (propane) by direct transesterification. In order to optimize the ethyl conversion, different temperatures (46.7–68.1 °C) and pressures (59.5–200.5 bar) were applied a central composite design rotational (CCDR) obtaining the high conversion (74.39%) at 50 °C and 180 bar. The molar ratio also was investigated showing conversions ~ 90% using a molar ratio of 1:24 (oil:ethanol). From the best transesterification conditions, 50 °C, 180 bar, 20% enzymatic concentration, and 1:24 oil:ethanol molar ratio were obtained with success 98.9% conversion in 7 h of reaction. The enzyme reuse maintained its activity for three successive cycles. Thus, this simple process was effective to convert microalgal biomass into ethyl ester by direct transesterification and demonstrate high yields.

This work studied the fed-batch production of carotenoids by Sporidiobolus salmonicolor (CBS 2636) using agro-industrial waste as substrates (glycerol, corn steep liquor, parboiled rice waste). The feed rate was varied after 24 h of bioproduction, using glycerol (85 % pure and crude), peptone and malt extract in the feed. The maximum concentration of total carotenoids found was 4,400 μg/L in 96 h of process at the conditions: 25 °C, initial pH 4.0, stirring rate 180 rpm, aeration rate of 1.5 vvm (air volume per volume of culture medium per minute), 80 g/L glycerol, 15 g/L peptone and 5 g/L malt extract, with a feed rate of 112.5 mL each 12 h. The use of crude glycerol yielded maximum carotenoids of 3,009 µg/L. The specific production of carotenoids (Y p/x ) was 859.1 μg/g, and maximum specific growth rate (μ max) was 0.05 h−1. The highest cell production in this study was 0.085 g/L h.

This work aimed at evaluating the carotenoids production by a newly isolated Sporidiobolus pararoseus using agroindustrial substrates (glycerol, corn steep liquor and parboiled rice water). Bio-production was carried out in an orbital shaker, using 10% (w/v) of inoculum (25 °C, 180 rpm for 35 h), incubated for 120 h in a dark room. Liquid N 2 and dimethylsulfoxide (DMSO) were used for cell rupture and carotenoids were extracted with a solution of acetone/methanol (7:3, v/v). Optimization of carotenoids bio-production was achieved by experimental design technique. Maximum concentration of 843 μg L −1 (β-carotene of 396 μg L −1 ) of carotenoids was obtained in a medium containing 40 g L −1 of glycerol, 40 g L −1 of corn steep liquor and 20 g L −1 of parboiled rice water, 25 °C, initial pH 4.0 and 180 rpm. The kinetic evaluation showed that the maximum concentration of total carotenoids was reached after 96 h of bio-production and that carotenoids production was associated with cell growth. The substrate consumption showed that at 96 h of bio-production consumption of 76% of total organic carbon (54% of glycerol) and 76% of nitrogen occurred.

The aim of this work was to perform the screening of microorganisms, previously isolated from samples of agro-industrial waste and belonging to the culture collection of our laboratory, able to produce polygalacturonases (PG). A total of 107 microorganisms, 92 newly isolated and 15 pre-identified, were selected as potential producers of enzymes with PG activity. From these microorganisms, 20 strains were able to synthesize PG with activities above 3 U mL(-1). After the kinetic study, the enzyme activity was increased up to 13 times and the microorganism identified as Aspergillus niger ATCC 9642 and the newly isolated W23, W43, and D2 (Penicillium sp.) after 24 h of fermentation led to PG activities of 30, 41, 43, and 45 U mL(-1), respectively. The RAPD analysis demonstrated that the selected strains differs genetically, indicating that no duplication of strains among them in the experiments for polygalacturonases production was verified.