Showing papers by "Mohammed Farid published in 2018"

SO2, high pressure processing and pulsed electric field treatments of red wine: Effect on sensory, Brettanomyces inactivation and other quality parameters during one year storage

Abstract: The use of sulphur dioxide (SO2), high pressure processing (HPP) and pulsed electric fields (PEF) for wine preservation was compared. The difference between HPP and PEF wines and untreated wine after one year's storage, in terms of sensory quality, B. bruxellensis inactivation, colour density, total phenolic content and volatile phenol concentration, was determined. SO2 and HPP led to >5 log inactivation of B. bruxellensis, however SO2 treated cells were able to recover after 10 months storage. PEF treatment provided insufficient inactivation (0.8 log reduction). HPP was the only treatment which prevented Brettanomyces growth and the formation of off-flavours and –odours after storage. SO2 and PEF treatments had no significant effect on wine quality, while the colour and phenolic quality of HPP treated wine deteriorated after six months. HPP and PEF also had no effect on the overall sensory quality of the wines. Overall, HPP was able to produce a microbiologically stable wine, with no effect on the taste of the wine. Industrial relevance Brettanomyces is a spoilage concern in the wine industry, conventionally controlled using SO2. Due to its adverse effects on some consumers, the use of emerging non-thermal technologies has started to garner great interest in the food and beverage industry. The results show that HPP is a non-thermal treatment with the potential to reduce the use of SO2 for the preservation of wine in the industry. However, to extend the quality of HPP treated wine beyond six months storage and retain wine colour and total phenolic content, small doses of SO2 may be required. Since, PEF is a continuous process, integration of this technology into current wine production practices would be less challenging than for HPP. This study also underscores the importance on conducting regular tests for B. bruxellensis contamination in the wine industry, because even when plate counts are negligible this yeast has the ability to recover when conditions become favourable again.

Approach for Polygodial Extraction from Pseudowintera colorata (Horopito) Leaves Using Deep Eutectic Solvents

Abstract: Polygodial is a bioactive compound that is present in an ancient native plant known as “horopito” (Pseudowintera colorata) in New Zealand, and it possesses antifungal, antibacterial, antifeedant, insecticidal, and antithelmintic properties. In this work, an approach for polygodial extraction using deep eutectic solvents (DESs) is presented. Two newly prepared DESs based on 1-dodecanol and polyethylene glycol were found to be comparable with ethanol in their polygodial extractability. However, they exposed a superior ability to protect polygodial from degradation and also a better solvent reusability for extraction of polygodial as compared to ethanol. The Box-Behnken design (BBD) in combination with response surface methodology (RSM) was used to design the experiment and optimization of polygodial extraction using the dodecanol-based DES. The optimal condition was acquired at 47.13 °C, for 1.03 h, and 5.01% w/v biomass, where 12.35 ± 0.05 mg of polygodial/g of dried horopito leaf was extracted.

Effect of Subcritical Water on the Extraction of Bioactive Compounds from Carrot Leaves

Abstract: Carrot leaves, which are generally considered as agricultural residue, are rich in bioactive compounds, such as polyphenols This study investigates the extraction of polyphenols and luteolin (flavonoid) from freeze-dried and ground carrot leaves (d < 100 μm) using subcritical water (SCW) Water at elevated temperatures and at high pressure (40 bar) could behave as low-polar solvent to enhance extraction of organic compounds SCW was investigated at different temperatures (110–230 °C), time (0–114 min), and solid-liquid ratio (15 and 35 g/L) Accordingly, it was revealed that total phenolic content (TPC) from carrot leaves using SCW has an increasing trend with temperature and resulted in 4283 ± 185 mg per g of dry weight in gallic acid equivalent at 210 °C/1135 min However, luteolin content using SCW extraction behaved differently, where increase of temperature adversely affected its content Hot water extraction studies revealed the presence of optimum luteolin content (0768 ± 0009-mg/g dry weight) at 120 °C for 10 min In conclusion, it was shown that carrot leaves are a promising feedstock to extract polyphenols that has high content of luteolin

Effect of thermal and high pressure processing on stability of betalain extracted from red beet stalks

Abstract: Red beet stalks are a potential source of betalain, but their pigments are not widely used because of their instability. In the present work, the applicability of high pressure processing (HPP) and high temperature short time (HTST) thermal treatment was investigated to improve betalain stability in extracts with low and high concentrations. The HPP was applied at 6000 bar for 10, 20 and 30 min and HTST treatment was applied at 75.7 °C for 80 s, 81.1 °C for 100 s and 85.7 °C for 120 s, HPP treatment did not show any improvement in the betalain stability. In turn, the degradation rate of the control and the HTST thermal treatment at 85.7 °C for 120 s of the sample with high initial betalain concentration were 1.2 and 0.4 mg of betanin/100 ml of extract per day respectively. Among the treatments studied, HTST was considered the most suitable to maintain betalain stability from red beet stalks.

Assessing the nearly zero-energy building gap in university campuses with a feature extraction methodology applied to a case study in Spain

Abstract: Public universities face the challenge of retrofitting the actual campus buildings into nearly zero-energy buildings (NZEB). In this study, a novel methodology for evaluating historical energy use and renewable energy production for all the buildings of a university, including hourly, daily and monthly data assessments is presented. This analysis is useful as a baseline for comparisons with future energy retrofits and enables determining the current gap between actual energy indicators at building and campus levels and the established limits for NZEB non-residential buildings in the European Union. The methodology is applied to a case study at the University of Lleida, a typical average-size university in Spain. Results show a wide variation in energy use among campus buildings, ranging between 50 and 470 kWh/m2 year. Constant or slightly increasing energy use and decreasing trends in renewable energy generation are observed. The daily electricity profiles have shown similar patterns among buildings and substantial potential energy savings during unoccupied periods. In the NZEB analysis, the average non-renewable primary energy use is about 4 times higher than the maximum estimated Spanish threshold range of 45–55 kWh/m2 year. Deep energy renovation strategies are, thus, needed for universities to meet EU NZEB targets.