Production Of Undesirable Compounds Research Articles

Contaminated Perry in Patagonia Argentina: A Case Study.

Perry is a beverage obtained by fermentation of pear juice, popular in the North Hemisphere. In Argentina it is an emerging market, particularly in the Patagonian region. The aim of this work is to describe and to evaluate the spoilage yeasts associated to six perry samples showing signs of microbiological contamination from a local craft perry company in North Patagonian region. Eighteen yeasts were isolated from four of the six perry samples where Brettanomyces custersianus, Brettanomyces bruxellensis and Zygosaccharomyces parabailii were identified. The growth capacity of these isolates in the presence of antimicrobial agents (sulfite and potassium sorbate) was analyzed in solid media. Growth parameters in sterile perry must was evaluated and the production of undesirable compounds were evaluated, products were characterized in terms of their aromatic and physicochemical features. The yeasts Z. parabailii NPCC1791 was able to grow on plates containing sulfite concentrations of up to 4mM and produced high methanol concentrations in perry. Additionally, B. bruxellensis NPPC1792 was able to produce methanol as well as high concentrations of volatile phenols including 4-ethylphenol and 4-ethylguaiacol. These results demonstrate the potential of these species as perry contaminants. Given the lack of studies describing the contaminating yeasts in perry production, this work represents the first report about perry spoilage yeasts in Argentina, with this knowledge, control strategies can be developed to prevent microbiological contamination and minimize product loss.

Selection of yeasts from bee products for alcoholic beverage production.

The use of appropriate yeast strains allows to better control the fermentation during beverage production. Bee products, especially of stingless bees, are poorly explored as sources of fermenting microorganisms. In this work, yeasts were isolated from honey and pollen from Tetragonisca angustula (Jataí), Nannotrigona testaceicornis (Iraí), Frieseomelitta varia (Marmelada), and honey of Apis mellifera bees and screened according to morphology, growth, and alcohol production. Bee products showed to be potential sources of fermenting microorganisms. From 55 isolates, one was identified as Papiliotrema flavescens, two Rhodotorula mucilaginosa, five Saccharomyces cerevisiae, and nine Starmerella meliponinorum. The S. cerevisiae strains were able to produce ethanol and glycerol at pH 4.0-8.0 and temperature of 10-30 °C, with low or none production of undesirable compounds, such as acetic acid and methanol. These strains are suitable for the production of bioethanol and alcoholic beverages due to their high ethanol production, similar or superior to the commercial strain, and in a broad range of conditions like as 50% (m/v) glucose, 10% (v/v) ethanol, or 500 mg L-1 of sodium metabisulfite.

Evaluation of the lard oxidative stability added with rosemary extract and rosemary essential oil

The production of undesirable compounds from oxidative processes in oils and fats is a problem when it comes to extending shelf life or deep-fat frying foods. In this work the use of rosemary extract and rosemary essential oil in the lard submitted to thermoxidation was evaluated and compared with the synthetic antioxidant TBHQ.The extract obtained from solvent extraction and the rosemary essential oil were submitted to free radical analysis DPPH • and ABTS •+ , total phenolic compounds and total flavonoids. The lard was divided into four treatments: lard (control), lard + 100 mg kg -1 TBHQ (L + TBHQ), lard + 100 mg kg -1 rosemary extract (L + RE) and lard + 100 mg kg -1 rosemary essential oil (L + REO). The treatments were submitted to thermoxidation at 180°C, where samples were taken off at intervals of 0, 5, 10, 15 and 20 hours. The samples were analyzed for free fatty acid content, peroxide index and conjugated dienes. The extract showed better antioxidant potential when compared to the essential oil (15.20 and 18.51 mg mL -1 for EC 50 ; 917.87 and 321.71 μmol ET mL -1 , respectively). The analysis for total phenolics compounds and total flavonoids showed no statistical difference (99.55 and 80.88 mg EAG L -1 ; 29.79 and 31.42 μg ER mL -1 , respectively). During the analysis of the thermoxidated lard, the rosemary essential oil showed results as favorable as those obtained by the antioxidant TBHQ, showing that the antioxidants from natural source can be a good alternative to synthetics ones.

Optimized rapeseed oil enriched with healthy micronutrients: a relevant nutritional approach to prevent cardiovascular diseases. Results of the Optim'Oils randomized intervention trial

Rapeseeds are naturally rich in cardioprotective micronutrients but refining leads to substantial losses or the production of undesirable compounds. The Optim'Oils European project proposed innovative refining conditions to produce an optimized rapeseed oil enriched in micronutrients and low in trans linolenic acid. We aimed to investigate cardioprotective properties of this Optimized oil. In a randomized, double-blind, controlled, cross-over study, 59 healthy normolipidaemic men consumed either Optimized or Standard rapeseed oils (20g/d) and margarines (22g/d) for 3weeks. The Optimized oil reduced the trans FA concentration (p=0.009) and increased the contents of alpha-tocopherol (p=0.022) and coenzyme Q10 (p<0.001) in comparison with the Standard oil. Over the 3-week trial, Total-/HDL-cholesterol and LDL-/HDL-cholesterol were increased by 4% (p<0.05) with the Standard oil consumption whereas none of them rose with the Optimized rapeseed oil which increased the HDL-cholesterol and ApoA1 plasma content (+2%, NS and +3%, p<0.05 respectively). The effects observed on the plasma HDL-cholesterol levels (p=0.059), the Total-/HDL-cholesterol ratio (p=0.092), and on the ApoA1 concentrations (p=0.060) suggest an improvement of the cholesterol profile with the Optimized rapeseed oil. Finally, the Optimized oil reduced the plasma content of LDLox (-6%, NS), this effect being significantly different from the Standard oil (p=0.050). In conclusion, reasonable intake of an Optimized rapeseed oil resulting from innovative refining processes and enriched in cardioprotective micronutrients represent a relevant nutritional approach to prevent the risk of cardiovascular diseases by improving the cholesterol profile and reducing LDL oxidation.