Determination of the concentration of total phenolic compounds in aged cachaça using two-dimensional fluorescence and mid-infrared spectroscopy.

In this work, we investigate alternative quantification methods based on optical spectroscopy and variable selection approach, using as a case study the aging process of cachaça. The cachaça was aged in an Amburana barrel and the samples were analyzed with a traditional analytical method for total phenolic quantification (Folin-Ciocalteu), with 2-D fluorescence and infrared spectroscopy. We applied a methodology based on Ant Colony Optimization to optimize variable selection and model fitting to predict total phenolic content. Our results demonstrated that fluorescence spectroscopy was more sensitive than IR in the quantification of total phenolic compounds for both global and local models, presenting good results (R2 superior to 0.979), significantly reducing the number of original variable (1995) for only 4 pairs of Ex/Em. Variable selection combined with spectroscopy reveals potential because this technique eliminates the need for sample preparation and allows the construction of customized sensors for application in the food industry.

Alternative Process for Production of Sweet Potato Distilled Beverage

Abstract Shochu is the most widely consumed spirit in Japan. In its manufacture is used koji, a solid fungus culture traditional of the Asian countries, but that makes the production process slow. Shochu can be produced from a variety of starchy sources, including sweet potato. About 7% of the world's sweet potato production is wasted due to imperfections that make it unsuitable for consumption. However, this material can be used in ethanol production. Considering the high productivity of sweet potato in Brazil, an opportunity to add value to this raw material is perceived. An alternative process for the production of sweet potato distillate similar to shochu was proposed. Koji was replaced by a mixture of alpha-amylase and glucoamylase. Process time was reduced from 14 to only 1 day. Composition analyses were performed by HPLC and GC. The experimental yield of alcoholic fermentation using pectinase enzyme reached 67.31-73.65%, but methanol was above the limits of the legislation. Without the addition of pectinase, no methanol was formed. However, there was a decrease in yield (51.65-54.75%), due to the incomplete disintegration of sweet potatoes. The distillate produced and the commercial shochu presented the same absorption bands in FTIR analysis, identifying the similarity between them.

Raman spectroscopy for monitoring carotenoids in processed Bunchosia glandulifera pulps.

Raman spectroscopy is a rapid and non-destructive analytical technique that has found a growing interest in the characterization and quantification of microconstituents in foods. In this work, Raman spectroscopy was used to evaluate the carotenoids content of processed Bunchosia glandulifera, a native fruit from the Brazilian Atlantic Forest. The B. glandulifera pulps were dried in hot air at 65 and 85 °C, resulting in carotenoids degradation of about 75 and 80%, respectively. The degradation profile of carotenoids over time was analyzed by Raman spectroscopy, with and without the use of an internal standard (TiO2). The reproducibility of the analyses was evaluated by PCA of spectral data. PLS regression was applied for modelling the total carotenoids in B. glandulifera. Resulting models show the Raman data correlate with carotenoids content on samples resulting in a satisfactory coefficient of determination for all sets of samples.

Development of a quantitative approach using Raman spectroscopy for carotenoids determination in processed sweet potato.

The orange-fleshed sweet potato is a vegetable-rich in carotenoids. The thermic treatment for sweet potato processing can decrease the content of these constituents in the foods, lowering their bioactive properties. Raman spectroscopy has been growing as a fast tool to food analysis, especially for detection of low concentrations of carotenoids and to the monitoring of its degradation profile over time. Therefore, in this work were evaluated two methods of drying, hot air and microwaving with rotary drum, combined with quantitative Raman spectroscopy. The results showed carotenoids degradation around 50% for both types of drying processes studied. PCA plot proved the potential of reproducibility of analyses for microwave drying samples. For samples heated with hot air, the best linear correlation achieved was R2 = 0.90 and by microwave was R2 = 0.88. Also, partial least squares (PLS) regression models were constructed obtaining a satisfactory coefficient of determination.

Growth of microalgae Scenedesmus sp in ethanol vinasse

This study evaluated the feasibility of using vinasse as a nutrient source for microalgae cultivation. The Scenedesmus sp was grown in a medium supplemented with vinasse and process variables were optimized using a factorial design and a Central Composite Design (CCD). The factorial design results showed that it was possible to cultivate microalgae at concentrations of up to 40% of vinasse in the culture medium. The CCD results showed that the light intensity and vinasse concentration influenced the amount of biomass produced.

Fast microwave-assisted pyrolysis of microalgae using microwave absorbent and HZSM-5 catalyst.

Fast microwave-assisted pyrolysis (fMAP) in the presence of a microwave absorbent (SiC) and catalyst (HZSM-5) was tested on a Chlorella sp. strain and on a Nannochloropsis strain. The liquid products were characterized, and the effects of temperature and catalyst:biomass ratio were analyzed. For Chlorella sp., a temperature of 550 °C, with no catalyst were the optimal conditions, resulting in a maximum bio-oil yield of 57 wt.%. For Nannochloropsis, a temperature of 500 °C, with 0.5 of catalyst ratio were shown to be the optimal condition, resulting in a maximum bio-oil yield of 59 wt.%. These results show that the use of microwave absorbents in fMAP increased bio-oil yields and quality, and it is a promising technology to improve the commercial application and economic outlook of microwave pyrolysis technology. Additionally, the use of a different catalyst needs to be considered to improve the bio-oil characteristics.

Fast microwave assisted pyrolysis of biomass using microwave absorbent.

A novel concept of fast microwave assisted pyrolysis (fMAP) in the presence of microwave absorbents was presented and examined. Wood sawdust and corn stover were pyrolyzed by means of microwave heating and silicon carbide (SiC) as microwave absorbent. The bio-oil was characterized, and the effects of temperature, feedstock loading, particle sizes, and vacuum degree were analyzed. For wood sawdust, a temperature of 480°C, 50 grit SiC, with 2g/min of biomass feeding, were the optimal conditions, with a maximum bio-oil yield of 65 wt.%. For corn stover, temperatures ranging from 490°C to 560°C, biomass particle sizes from 0.9mm to 1.9mm, and vacuum degree lower than 100mmHg obtained a maximum bio-oil yield of 64 wt.%. This study shows that the use of microwave absorbents for fMAP is feasible and a promising technology to improve the practical values and commercial application outlook of microwave based pyrolysis.

Influence of NaNO3 concentration and incident light intensity on Nannochloropsis oculata lipid accumulation

This study aimed at evaluating the best conditions for lipid accumulation in the marine microalga Nannochloropsis oculata in an airlift photobioreactor. Experiments were carried out following a central composite design with the following variables: temperature (19 to 29°C), sodium nitrate concentration (NaNO3) in the culture medium (f/2) (25 to 125 mg.L-1) and incident light intensity (49 to 140 µE.m-2s-1). The maximum lipid production was 132.4 mg.L-1 under the following conditions: 27°C, NaNO3 concentration 105 mg.L-1 and 122 µE.m-2.s-1, which was 30% of dry weight of the biomass.

Tanneries: from waste to sustainability

The aim of this work was to look for an efficient and environmentally safe solution for the leather tanning industry through a problem of non-linear programming. The results were promising and showed a significant potential of wastewater reduction. Reuse of internal streams reduced around 70 percent wastewater. The solutions obtained could reduce significantly the amount of chemicals and consequently the amount of waste to be treated.