Microwave-Assisted Extraction of Pectin from "Saba" Banana Peel Waste: Optimization, Characterization, and Rheology Study.

One way to valorize "Saba" banana peel waste is to extract high-value compounds, such as pectin, and use it for food applications. In this study, the parameters for the microwave-assisted extraction of pectin were screened and optimized using Response Surface Methodology. The pectin was purified and then subjected to characterization. Results showed that the optimum extraction conditions were 195°C, 8% solid-liquid ratio, and pH 3 hydrochloric acid (HCl), with predicted and actual yields of 12.8% and 14.2%, respectively. The subsequent purification method increased the purity of pectin by 300%. The pectin was found to be low-methoxy in nature and had an average particle size of 300 nm. The pectin application in whey protein isolate resulted in a shear-thinning fluid, with an improved viscosity compared to a control. When applied to a commercial orange juice, the in vitro digestion study showed that the fluid's viscosity was higher before and during the gastric and intestinal digestion at the low physiological shear rate.

Metal Concentrations in Sediments of the Alinsaog River, Santa Cruz, Zambales, Central Luzon, Philippines.

BACKGROUND: Efforts are needed to evaluate heavy metal concentrations in aquatic sediments which serve as repositories and as sources of contamination of other habitats. OBJECTIVES: The present study assessed temporal changes in the pH, particle size and concentration of metals in sediments of a mining-affected river in Zambales, Philippines. METHODS: Sediment samples were collected at different periods in four stations along the river using a modified Van Veen grab. The samples were subjected to quartering, air-drying, and sieved through a mesh of 40 mm prior to X-ray fluorescence spectroscopy analysis using Thermo Scientific Niton XL3t to determine metal concentrations. The sediment particle size was analyzed by the sieve method and soil pH by the electrode method. RESULTS: Measured metal concentrations in the sediment were as follows: iron (Fe)> calcium (Ca)> chromium (Cr)> nickel (Ni)> manganese (Mn) with averages of 174.6 mg/g, 7.89 mg/g, 6.54 mg/g, 4.82 mg/g, and 2.75 mg/g dry matter (DM), respectively. The mean pH of riverine sediments was generally neutral, except for Station 4. In terms of particle size, silt and clay fractions increased in the upstream station but decreased in the midstream and downstream stations across the sampling periods. The flooding brought by Typhoon Koppu resulted in lowered concentrations of Fe, Mn, Cr, and Ni and an upsurge in Ca and potassium levels. DISCUSSION: Most of the heavy metals (Fe, Ni, Cr, Mn) exceeded the probable effect level (PEL) for inorganics in sediments, suggesting that the adverse effects of these metals on the environment and aquatic organisms are expected to occur frequently. In comparison with Station 4, which was less affected by siltation, there was a sign of metal enrichment in the area. This indicates that soil erosion and runoff, which might have been triggered by vegetation loss, mineral extraction, and agricultural activities, had a significant impact on the quality of river sediments. CONCLUSIONS: The findings of the study point to the need for the formulation and implementation of appropriate regulatory measures for the protection and rehabilitation of the heavy metal-loaded river. COMPETING INTERESTS: The authors declare no competing financial interests.

Preliminary Water and Sediment Quality Assessment of the Meycauayan River Segment of the Marilao-Meycauayan-Obando River System in Bulacan, the Philippines.

BACKGROUND: The Meycauayan River is considered one of the most severely polluted rivers in the Philippines due to heavy metal and organic pollution that has caused environmental degradation. OBJECTIVES: The aim of the present study was to provide insight on the current status of the Meycauayan River and outline an appropriate strategy to solve problems of organic and heavy metal contamination. METHODS: The physical, chemical and biological characteristics of the water and sediments were analyzed and evaluated based on available local and international standards. Three sites (upstream, midstream and downstream) of the river were considered for the evaluation of water and sediment quality. RESULTS: Dissolved oxygen, measured in the morning, was very low at the upstream sampling station (1.87 ppm) and even lower at the downstream site (0.49 ppm). The temperature for the three sites ranged from 28.03°C (upstream) to 30.75°C (downstream). Visual inspection indicated that the color of the water was gray upstream and midstream, and black at the downstream station. Biochemical oxygen demand exceeded the recommended limits of the Department of Environment and Natural Resources (DENR) of 7.0 ppm with values of 13.22 ppm (upstream) and 12.02 ppm (downstream). Chemical oxygen demand exceeded the limit of 20 ppm at the downstream site at 84 ppm. Dissolved oxygen did not reach the recommended limit of 5.0 ppm of the DENR. There was a high coliform count at both the upstream (3.5 × 104 colony-forming unit (cfu)/ml) and downstream (2.5 × 104) sites, which exceeded the limit of the United States Environmental Protection Agency (USEPA) of 126 cfu/100 ml. Heavy metals such lead (Pb), zinc (Zn), copper (Cu), manganese (Mn) and chromium (Cr) exceeded the severe effect level of the National Oceanic and Atmospheric Administration (NOAA), which could be detrimental to humans and aquatic life. The results of one-way analysis of variance showed significant differences (p <0.001) in pH, temperature, dissolved oxygen, conductivity, total dissolved solids, chemical oxygen demand, nitrates and phosphates for water quality and Pb, Zn, Cu, Mn and Cr for sediment quality across the study sites. CONCLUSIONS: The results of the present study indicate that the downstream site was more polluted, possibly due to the accumulation of pollutants coming from the upstream site. The deterioration of the Meycauayan River is a result of rapid industrialization, urbanization and population growth. Examination of the water quality of the Meycauayan River indicates that it is very polluted and requires an immediate solution. The results of the present study should be used as a basis for crafting strategies to rehabilitate the Meycauayan River. COMPETING INTERESTS: The authors declare no competing financial interests. This study was funded by Pure Earth.

Impact of Abandoned Mining Facility Wastes on the Aquatic Ecosystem of the Mogpog River, Marinduque, Philippines.

BACKGROUND: Mine waste from abandoned mining sites can cause environmental degradation and ecological imbalance to receiving water bodies. Heavy metal pollution affects local communities and may pose health risks to the general public. An abandoned mining facility in Marinduque, Philippines, situated on the of Mogpog River, continuously deposits mine wastes, which may affect the river and the health of local communities. OBJECTIVES: The aim of the present study was to examine the presence and extent of heavy metal contamination from mine wastes in the aquatic ecosystem of the Mogpog River by determining the level of heavy metal concentration in the water, sediments and biota. METHODS: Four sampling sites were monitored for heavy metals (copper (Cu), arsenic (As), chromium (Cr) and sulfur (S)) pollution. Several analyses were conducted to determine the heavy metals present in the water, sediment and biota. Atomic absorption spectrophotometry was used for the analysis of Cu concentrations in water. X-ray fluorescence was used for the analysis of total heavy metals in the sediments and biota. RESULTS: An inverse relationship with water and sediment from upstream to downstream of the river were observed. This trend shows deposition of Cu in the sediments as factored by pH. Flora gathered from the riverbanks recorded concentrations of Cu in their leaves and fruits. CONCLUSIONS: It has been difficult for the Mogpog River to regain water quality after years of mine waste deposition. Acid mine drainage occurred upstream of the river which affects the speciation of heavy metals. The potential risk of heavy metal exposure to local communities was observed due to the communities' river utilization. PARTICIPANT CONSENT: Obtained. ETHICS APPROVAL: The Office of Vice Chancellor for Research and Extension of University of the Philippines Los Baños approved the study. COMPETING INTERESTS: The authors declare no competing financial interests.

Assessment of the Effect of Remediation Strategies on the Environmental Quality of Aquaculture Ponds in Marilao and Meycauayan, Bulacan, Philippines.

BACKGROUND: Water quality in the Marilao-Meycauayan-Obando river system (MMORS) of Bulacan, the Philippines, is of great concern due to the pollution load from local industries. The river system is currently used as a source of water for the aquaculture industry in Bulacan. OBJECTIVES: In order to address organic and heavy metal pollution, several remediation strategies were tested in aquaculture ponds along the river system. Strategies such as phytoremediation (vetiver grass pontoons), application of probiotics and zeolite (with filtration as pre-treatment) were utilized in ponds to decrease or remove toxic pollutants in water and sediments. METHODS: Two sites were chosen as the pilot remediation sites - ponds in Barangay Nagbalon, Marilao and Barangay Liputan, Meycauayan, Bulacan. Pond bottom preparation was done to improve the condition of the pond bottom sediments before stocking by adding zeolite. Physicochemical parameters of water such as dissolved oxygen (DO), temperature, pH, salinity, ammonia, phosphate, biochemical oxygen demand (BOD) and chemical oxygen demand (COD) were monitored throughout the culture period. Heavy metals in sediments and fish were monitored. Fish parameters such as average body weight and feed conversion ratio were determined. RESULTS: The DO levels were below recommended levels in the morning and reached a supersaturated level in the afternoon. Ammonia and COD levels were above recommended limits. A decreasing trend was observed for ammonia levels in treatment ponds. In terms of the growth of milkfish, the pond with probiotics showed the highest growth and better feed conversion ratio in Nagbalon and in the phytoremediation pond in Liputan. Percentage survival of milkfish was much higher at Liputan. Copper, chromium, lead and manganese were detected in pond sediments. After application of zeolite, there was a decrease in lead levels throughout the culture period. CONCLUSIONS: The different remediation studies were compared in terms of cost, effectivity and application and phytoremediation (vetiver grass pontoons) was determined to be the most cost-effective remediation strategy. COMPETING INTERESTS: The authors declare no competing financial interests.

Functional group analysis during ozonation of sunflower oil methyl esters by FT-IR and NMR.

Ozonation of neat sunflower oil (SFO) methyl esters was monitored by FT-IR and 1H and 13C NMR spectroscopy. During the early stage of ozonation, ozone absorption was essentially quantitative. This was accompanied by the formation of 1,2,4-trioxolane. IR and NMR spectra of ozonated samples showed that scission of ozonide to give aldehyde were minimal. 1H NMR analysis revealed that the amount of ozonide relative to aldehyde was more than 90% regardless of the extent of ozonation. Complete ozonation was attained after supplying around 0.20 g O3/ml methyl ester after which ozone absorption suddenly dropped to around 25%. At the latter part of ozonation, ozonide and aldehyde reacted with excess ozone to give carboxylic acid. Reaction products were identified according to Criegee mechanism.