Carotenoid Assessments and Antioxidant Activities from Flower Petals

The objectives of this study were to evaluate carotenoid pigment profile and the antioxidant activity from 14 commonly grown flowers in Thailand. The result found that orange marigold showed the highest total carotenoid content at as 2,209±75.58 µg/g, followed by deep yellow chrysanthemum at 551.27±47.72 µg/g (P<0.01). The next lower total carotenoid content group was found in yellow silk cotton, yellow trumpetbush, yellow marigold and yellow golden shower with total carotenoid content of 447.42±27.56, 429.46±28.34, 409.85±34.58 and 363.88±12.74 µg/g, respectively. The highest antioxidant activities against DPPH and ABTS radicles were found from orange marigold, which were 32.34±2.16 and 50.08±0.87%, respectively. Deep yellow chrysanthemum, yellow silk cotton, yellow trumpetbush, yellow marigold and yellow golden shower also showed significantly higher antioxidant activities than other flowers (P<0.01). Total carotenoid contents well correlated with antioxidant activities against DPPH and ABTS radicals (r = 0.6924 and r = 0.8270, respectively) at P<0.01. TLC result elucidated that orange marigold, yellow silk cotton and yellow golden shower were a good source of β-carotene, while deep yellow chrysanthemum and yellow marigold were a good source of lutein and/or zeaxanthin. The result indicated that flower petals would be useful as natural carotenoid source and provide antioxidants for food industry

Extraction and characterization of pectin from selected indigenous fruits for further commercial application in food industries

The aims of this study were to extract pectin from selected indigenous fruits, including breadfruit, papaya and santol as well as investigate the chemical and physical properties of extracted pectin to address the potential of these fruits as an alternative source of commercial pectin. Different parts of fruits were used to extract pectin under the acid condition method. Pectin yield ranged from 8.52±0.05 to 49.96±0.89% and breadfruit was the highest pectin source. The extracted pectin from breadfruit was categorized as high methoxyl pectin with the degree of esterification between 93.57±0.22 to 96.70±0.17%, which was almost 2-time higher than the commercial pectin (53.10±1.25%). The galacturonic acid contents found in the extracted pectin varied widely from 41.41±0.09 to 73.19±0.59%. The significantly highest galacturonic acid content was found in the pectin extracted from the peel of breadfruit, which strongly indicated that pectin extracted from the peel of breadfruit was good quality. The FT-IR spectra also confirmed that the pectin obtained in this study was overall similar to the commercial pectin. Therefore, the breadfruit peel was highly recommended as a potential alternative source of pectin

Screening and identification of lactic acid bacteria with antimicrobial activity against food-borne pathogen

วารสารวิชาการและวิจัย มทร.พระนคร, 10 (2) : 86-93This study focused on screening and identification of lactic acid bacteria with antimicrobial activity against Escherichia coli from milk samples. There were 250 isolates, showing different antimicrobial activities. Five isolates with predominant anti-E. coli efficiency were chosen for the study of bacteria identification, bacterial growth as well as the stability in pH change, heating and proteolytic treatment. The sequences of 16s rDNA indicated that selected isolates were Lactobacillus sp.. The antimicrobial efficiency, described in the term of Antimicrobial Index (AI) ranged from 0.63 to 0.84. However, the anti-E coli activity did not change when performing the test under proteinase-treated condition and high temperature-treated condition. Conversely, the pH adjustment of cell-free bacterial culture to 7.0 demolished their antimicrobial activity. This data implied that their antimicrobial activities were results of acidic condition, produced by lactic acid bacteria. From this study, the selected lactic acid bacteria showed their potential as a starter culture for fermented foods.Rajamangala University of Technology Phra Nakho

Development of Bio-Electrochemical Reactor for Groundwater Denitrification: Effect of Electric Current and Water Hardness

Nitrate-nitrogen (NO3-N) contaminating groundwater is an environmental issue in many areas, and is difficult to treat by simple processes. A bio-electrochemical reactor (BER) using copper wire and graphite plate was developed to purify the NO3-N-contaminated groundwater. The low (of 10 mA) and high (of 20 mA) electric currents were applied to the BERs, and various influent hardness levels from 20 to 80 mg/L as CaCO3 due to groundwater characteristics were supplied to clarify the total nitrogen removal efficiency and NO3-N removal mechanisms. In the BER-10, the bio-electrochemical reactions caused 85% of total nitrogen to be removed through heterotrophic and autohydrogenotrophic denitrification in the suspended sludge and biofilm. However, the chemical deposit occurring at the cathode from water hardness affected the decreasing denitrification performance; 12.6% of Mg and 8.8% of Ca elements were observed in the biofilm. The enhancement of electrochemical reactions in the BER-20 caused integrating electrochemical and bio-electrochemical reactions; the NO3-N was electrochemically reduced to NO2-N, and it was further biologically reduced to N2. A better total nitrogen removal of 95% was found; although, a larger deposit of Mg (22.8%) and Ca (10.8%) was observed. The relatively low dissolved H2 in the BER-20 confirmed that the deposit affected the decreasing gaseous H2 transfer and inhibition of autohydrogenotrophic denitrification in the suspended sludge. According to the microbial analysis, both heterotrophic and autohydrogenotrophic denitrification were obtained in the suspended sludge of both BERs; Nocadia (26.8%) was the most abundant genus in the BER-10, whereas Flavobacterium (27.1%) and Nocadia (25.0%) were the dominant genera in the BER-20

Application of Electrocoagulation in Street Food Wastewater

Street food is commonly known as ready-to-eat and go foods and beverages, which is very famous in Thailand and other Asian countries. The street food daily generates high organic content and oily wastewater from washing and rinsing plates. The discharge of street food wastewater to public drains leads to a clogged drain line and unpleasant smell. In this work, an electrocoagulation (EC) system with monopolar aluminum (Al) electrodes was developed to treat two well-known street foods; Hainanese chicken rice (HC) and noodles and dumplings (ND). The results revealed that excellent chemical oxygen demand (COD) and fat, oil, and grease (FOG) removals were achieved under a specific operating condition (i.e., an electric current of 20 mA/cm2 and electrolytic time of 10 min). The initial COD of HC wastewater decreased from 40.6 g/L to 1.9 g/L, approximately 95%, whereas the FOG decreased from 310 mg/L to 50 mg/L, approximately 84%. The lower initial COD and FOG concentrations of ND wastewater obtained approximately 98% for COD removal and 86% for FOG removal; the effluent contained 0.5 g/L of COD and 25 mg/L of FOG. In addition, a relatively low Al concentration of 0.02–0.08 mg/L was observed in the effluents. The appropriate design factors together with ease of use and fast pollutants removal were significant advantages of this study; the EC system has potential to apply to on-site street food treatment

Novel Strategy for the Development of Antibacterial TiO2 Thin Film onto Polymer Substrate at Room Temperature

This work demonstrates a novel method to deposit an antibacterial TiO2 thin film on a polymer substrate at room temperature. A combination of sol–gel and photon assistance was used in the experiment in order to avoid any thermal processes of thin film crystallization. The morphological photograph of samples indicated that the TiO2 thin film was perfectly coated on the PVC substrate without any cracks or pinholes. Chemical analysis by EDS and XPS reported that the thin film consisted of titanium (Ti), oxygen (O), and carbon (C). The Raman spectrum proved that the thin film was the anatase phase of TiO2 and, furthermore, that it was contaminated with carbon remaining from the photon assistance process. In addition, the optical band gap of the thin film was 3.35 eV, suggesting that the photocatalytic activity of TiO2 should occur under UV-A radiation. The bacteria viability assay was examined using E. coli and S. typhimurium as indicator strains under UV-A irradiation (365 nm) at different times. The data from OD and CFU count revealed that >97% of bacteria were killed after 60 min of irradiation, and the bacteria were completely killed at 120 min for E. coli and 180 min for S. typhimurium